Chapter 1: Assessing Terrestrial Ecosystems, Aquatic Ecosystems, and Watersheds

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Summary

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF
Summary Sketch

Chapter 1: Ecological Integrity of Ecosystems


What are the resource conditions at the bio-regional level?


Aquatic Ecosystems

  • Rivers, streams, lakes, ponds, and springs make up diverse aquatic ecosystems across a wide variety of landscapes.
  • Conditions included here are water quality, biodiversity, and hydrology, and they vary widely by location and history.

Terrestrial Ecosystems

  • Forests, chaparral, grasslands, desert scrub, and alpine communities occur.
  • Geographical differences are related to differences in precipitation.
  • Conditions selected include: California habitat types; connectivity of forest carnivore habitat; vegetation heterogeneity; habitat elements; and fire restoration.
  • Vegetation is now more uniform and is younger.
  • High severity fires have created large patches of un-forested lands and fragmented landscapes.

Riparian Ecosystems

  • Vegetation, soils, and hydrology are important in every riparian ecosystem. These vary by location in landscape and types of aquatic and terrestrial ecosystems.
  • There are varying amounts of erosion and shifts in native plant communities.

Do these conditions across different areas of the bio-region? How?


  • The southern Sierra Nevada contains some of the least developed portions of the range, including national parks.
  • Important species limited to this area are the Giant Sequoia groves, Pacific fisher, and long-lived bristlecone pine and other subalpine conifers.
  • The lower elevation northern sub-region is more developed, with logging, ranching, and mining activities. Water quality is an issue in some of these areas.

What are the issues and problem areas at the bio-regional scale?


Aquatic Ecosystems

  • Fragmentation and climate change are the main issues at the bio-regional scale.
  • A high number of native fish species are of concern.
  • Unnaturally high severity fires cause fragmentation.
  • Water development is extensive in the bio-region.
  • Exotic, invasive species are degrading habitat in some areas.

Terrestrial Ecosystems

  • Fire suppression continues to influence landscapes.
  • Vegetation is more uniform than it was in the past, but overall it is denser with smaller trees or more decadent shrubs.
  • Important habitat elements of large trees and snags are at lower levels than in the past, and tend to be scattered or limited across the landscape.
  • Connectivity for mid and late-seral stage species is disrupted by large, more uniformly severe wildfires, particularly in montane pine and mixed conifer forests.
  • The Pacific fisher is limited to the southern Sierra Nevada, compared to historic records where it was throughout the range.
  • While the California spotted owl is well distributed, we have observed gradual but steady declines over the past 20 years.
  • Invasive species including barred owl, scotch broom, and cheat grass disrupt native communities.

Riparian Ecosystems

  • The issues experienced in riparian areas are a combination of aquatic and terrestrial ecosystems.
  • Fragmentation occurs from uncharacteristically severe wildfire, water development and flow, and fire suppression.
  • Denser conifer forests suppress riparian hardwoods.

Are there any specific issues and problem areas at each of the forest levels?


  1. The unique Sierran species, Giant Sequoia, Pacific fisher, and bristlecone pine, require specific management.
  2. Managed fire in upper elevations has restored fire to large landscapes. The challenge is to maintain and expand these areas.



Bio-Region Introduction

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF
Sierra Nevada Bio-region
Chapter 1: Ecological Integrity of Ecosystems

Current Condition

Overview

As the Pacific Southwest Region embarks upon Forest Plan Revision, it is important to consider the broader context in which individual national forests occur. This is particularly important for ecosystems and ecological integrity. Many plants and animals know no boundaries. Fires cross where they will. Species migrate over time. Although the Sierra Nevada mountain range is a distinct geological entity, there is no demarcation in vegetation types and cover where the southern Cascades begin. Because of these interconnected species, ecosystems and landscapes, this bio-regional topic paper, that provides the broader context for Forest Plan revisions, encompasses the Modoc National Forest south to the Sequoia National Forest (Map of the assessment area). This was the same area selected and included in the 1996 Report to Congress, Status of the Sierra Nevada, Sierra Nevada Ecosystem Project (SNEP). The same area was also encompassed by the 2001 and 2004 Sierra Nevada Forest Plan Amendment (Framework).

Forest Specific Ecological Integrity

This chapter is organized in a hierarchical manner. There are some subsections and indicators that are covered and discussed for the entire bio-region. The primary means is to break the bio-region into meaningful subregions as described in the introduction. The subregion is where the bulk of analytical information is found, using much of the same data that is available at the forest scale (such as forest inventory and vegetation mapping data). Since each of the three forests with forest plan revision in progress, the Inyo, Sequoia, and Sierra National Forests, have slightly different schedules for completing their plan revisions, there may be different approaches utilized by each forest to tier to the bio-regional topics.

Introduction and Background

Ecological integrity of ecosystems is a broad term. In the simplest explanation, ecology encompasses living things (i.e. plants, animals and other critters), their environment (i.e. air, soil, water), and how they interact or relate to each other. Ecosystems are defined by the different living and non-living things that occur together in any area. General examples include aquatic ecosystems (lake, stream and river), terrestrial ecosystems (forest, woodland, shrubfields or chaparral, rock outcrops, grasslands, alpine scree), and riparian ecosystems (stream or lakeside plants and animals).

Aquatic ecosystem – water based
aquaticecosystesmduck.jpg

Riparian ecosystem – interface between water and land
riparianpic.jpg

Terrestrial ecosystem – land-based
terrestrialpic.jpg


Ecological integrity is a harder to define concept. It has been characterized in various ways. According to the planning rule (36 CFR 219.19) it is defined as:

“The quality or condition of an ecosystem when its dominant ecological characteristics (for example, composition, structure, function, connectivity, and species composition and diversity) occur within the natural range of variation and can withstand and recover from most perturbations imposed by natural environmental dynamics or human influence.”

One way to address ecological integrity is through measure of key ecological functions or services (i.e. providing clean water or forests resilient to fire) or indirectly through comparison with the “natural range of variability”. There are pros and cons and uncertainty in utilizing either of these approaches. For example, with aquatic ecosystems in the bio-region, they have been heavily modified by water developments such as dams and diversions. Given the dependence of much of the state (and country and more) on the agricultural industry this water supports, power and municipal water supply, it is unlikely that a comparison with the historic range of variability will be as useful as what are the key ecological services and how are they affected by climate change and management actions to improve fire resilience and aquatic system restoration? For terrestrial ecosystems, the natural range of variability may be more relevant but there may be a high level of uncertainty around key elements such as the historic distribution and habitat uses by the California spotted owl or the Pacific Fisher. For vegetation composition and structure and the historic role of fire as a process, the natural range of variability approach may be more useful. In this assessment, we are utilizing a combination of approaches: both the natural range of variability and ecosystem service.

Vegetation composition and structure at the community, landscape and bio-regional scale will be addressed by considering the natural range of variability. Currently, detailed literature reviews and assessments are in progress by the US Forest Service Region 5 Ecology Program lead by Dr. Hugh Safford. Most other components or indicators of ecological integrity are being addressed in terms of current function and condition, lacking a good means to assess the natural range of variability for them.

Some of the most proximate measures for monitoring ecological integrity are indices of biological diversity (Lindenmayer et al. 2000). Typically it is very difficult to assess population parameters for very many species simultaneously, however birds are one group of species for which it is possibly and cost-effective to monitor many species with minimally invasive field survey techniques. Birds are ideal organisms for monitoring ecological integrity and being part of adaptive management process (Rich et al. 2004) for the following reasons:
1) They segregate at the micro-habitat level and have habitat relationships that are well known.
2) Most species are diurnal and sing repeatedly, they are exceptionally cost effective to monitor, quantify, and show to partners; typically a dozen or more species can be detected by a single method on a single visit.
3) Highly standardized data gathering protocols have been established for birds, and they are used throughout the continent.
4) Numerous long-term databases on birds and habitat currently exist and are cooperatively stored, managed and easily accessible through the Avian Knowledge Network.
5) Birds are perhaps the best group of species to compare across multiple geographic scales (project-level, state, regional, and continental).
6) Coexisting suites of bird species can include both ‘indicator’ and ‘umbrella’ species that are known to represent habitat conditions, ecosystem functions and other difficult to monitor species.

PRBO Conservation Science has an ongoing monitoring program, associated data base, and interactive web-based tool for over 100 bird species in and around all nine forest of the Sierra Nevada bioregion (http://data.prbo.org/apps/snamin/) that can assist current planning efforts and assess management actions on ecosystem integrity in the future.


Connectivity and structure of vegetation are being assessed in terms of function for wildlife habitat and floristic diversity. Fire was and is a key ecological process that shaped functional terrestrial and riparian ecosystems in the bio-region (van Wagtendonk and Fites-Kaufman 2006). It affected biological composition, structure, nutrient cycling, hydrologic regulation, and energy flow. Therefore, it is being used as an indicator for these other ecosystem processes that are more difficult to directly measure.

Selection of indicators and measures was based on a conceptual model framework as recommended by Noon (2003). In this approach, the interactions of processes and components of an ecosystem are considered and used as a basis for selecting those components or processes that are most important in the functioning and resilience of that ecosystem. Predators are often key components. As mentioned previously, fire is typically a key process in the western United States. Separate conceptual frameworks were constructed for aquatic, riparian, and terrestrial ecosystems. They are works in progress and we are working on scientific, interagency, and public collaboration to improve them. In general, we are utilizing a dynamic systems approach.

Coarse and Fine Filter Approaches for Monitoring Biodiversity
One of the fundamental and ongoing debates in forest management is centered on the scales and intensity of monitoring wildlife species to assess responses to changes in the environment. In a recent publication in the Journal of Wildlife Management (Schultz et al. 2013) several experts in wildlife conservation planning express concern of the Forest Service’s historic reliance on what is termed “coarse filter” approaches to monitoring wildlife species. The authors state, “Research indicates that the coarse-filter approach is unlikely to provide a reliable basis for multi-species conservation planning, (Cushman 2008), only limited testing of the approaches validity has occurred (Noon et al. 2009), and the monitoring of a select group of species using a fine-filter approach is necessary to determine the efficacy of coarse-filter approaches (Committee of Scientists 1999, Flather et al. 2009). A recent review of the degree to which coarse-filter models can be used to infer animal occurrence concluded that ‘..the observed error rates were high enough to call into question any management decisions based on these models’ (Schlossberg and King 2009).” The authors go on to state that the basic assumption that habitat is a valid proxy for species health is at best a risky stretch and at worst a weak and incomplete picture of the health, functioning and diversity of a particular ecosystem.

Another monitoring approach, also largely driven by expediency, postulates that species surrogates (indicator species) are adequate proxies for suites of species associated with various vegetation types across a landscape. In recent research (Cushman et al. 2010) examined 72,495 bird observations of 55 species across 1046 plots across 30 sub-basins and found “few significant indicator species relationships at either scale” where there was a presumed association.

In PSW-GTR-237, Managing Sierra Nevada Forests (2012) authors Malcolm North and Patricia Manley suggest that “coarse filter” approaches such as the California Wildlife-Habitat Relations model “generally fail to account for the different spatial and temporal scales at which species may respond to forest conditions or assess habitat features other than large trees and canopy cover.”

The Sierra Nevada Framework Environmental Impact Statement (2001) habitat projections for old forest attributes are an example of the coarse filter approach. Old forest habitat--large trees greater than 50 inches in diameter and large snags--were projected to increase significantly over a 140-year time scale. Oaks modeled to 60 years showed similar results. Yet, species monitoring has demonstrated that the California spotted owl, one of the key sensitive species of management concern closely tied to these habitat values, is currently experiencing a declining population trend (Keane 2013). The information regarding declining spotted owl trend was the result of fine-filter monitoring via a long-term spotted owl research project. If managers (and conservation advocates) were to rely simply upon the optimistic habitat projections in the 2001 Framework Plan and EIS (which the conservation community actively supported) we would be flying blind in what looks like an increasing grave situation for the owl’s survival.

Fine-filter monitoring approaches are less likely to oversimplify how animals use habitat and are more likely to capture effects of fine scale habitat fragmentation, predator-prey relations, behavioral responses to changed conditions, the value of understory diversity and snags and downed wood, landscape scale relationships or connectivity and spatial and temporal patterns of detection and non-detection.

In the new Forest Service Draft Directives, FSH 1909.12, Chapter 30 Monitoring, Section 32.12 “Selecting Monitoring Indicators,” stresses the financial feasibility, practicality, measurability and relevance to key monitoring questions. Section 32.13 establish eight monitoring indicators for tracking ecological conditions and progress toward desired conditions, plan objectives and important trends. Included in the directives are indicators to assess ecological conditions and status of focal species that are tied to ecological conditions.

These are generally coarse filter metrics that will be further defined in the specific revision of forest plans, including the Inyo, Sierra and Sequoia National Forest early adopter forests in California. Chapter 20 of the new Directives address the need for specific fine-filter standards when more general ecosystem indicators are not specific enough to address at-risk species needs such as nest tree protection or culverts allowing proper fish passage.

The National Forest Management Act requires the Forest Service to provide for a diversity of plant and animal species and not simply a range of ecological conditions that may or may not support diversity. The new Forest Service Planning Rule and its Directives system must ensure diversity of plant and wildlife species is maintained. The Forest Service’s obligation cannot devolve into a suite of invalid assumptions, ruled by efficiency which ultimately fail to meet the intent of the NMFA and the public’s expectation that Forest Service land managers will examine closely and rigorously the effects of management and changing conditions on the land.


At this time, we are not attempting to integrate condition of different indicators into a single combined evaluation of ecological integrity. However, it is likely that in the next phase, several options for doing this will be included. An example of this approach that is being considered includes the BLM Rapid Ecological Assessments (especially the Mojave Basin in progress).

In order to achieve valid measures of ecological integrity, the assessment will provide data on the quality and composition of non-conifer composition elements that are essential habitat features. These are so-called fine filter elements, but the proper way to think about them is that--as part of an ecological process--biological diversity emerges from niche partitioning. If there is not enough habitat in the different niches, species cannot find the resources they need, and there will be declines, particularly among those that are habitat specialists because there are fewer of them.T his is not just an either/or, fine grain versus coarse grain issue: it is essential to understanding ecological integrity for a biological assessment of this type.

Also, it is proper to use species that are rare or are thought to be in decline as priority “components” or indicators for the fine filter approach. In fact the FS is obligated to do so, under ESA and NEPA requirements to prevent species from becoming threatened with extinction. For example, if owl, fisher and marten and some subset of rare plants are focus species, then the discussion will need to be broad enough to capture the elements/components/indicators/ that are associated with these species. These will include the prey species, and the status of their food sources as well. Ecology requires a look up and down the food chain (as was done in the PNW spotted owl research), in order to understand the real capability of any given habitat or vegetation community.

Returning to a coarse filter approach in our example, several or more of the individual indicators deemed most important for ecological function are each rated with index values associated with sustainable, transitioning, and degraded conditions and then the values are combined. The combination of values can be a simple addition or an average. In this particular BLM example, the individual indicators combined were: landscape condition model index, landscape connectivity index, invasive plants index, fire regime departure, and change in extent. A similar approach is being examined for this assessment. Here, it may be most useful to combine different measures of biodiversity condition to generate a single rating that would be useful in ecosystem service evaluations.

The index or scorecard approach can also be approached with weighting different individual indicators, depending upon their perceived importance (to services or regulations) or vulnerability to stressors. Tools, such as the Vensim dynamic feedback model (http:/www.vensim.com), allow “what if” evaluations of different weights for different indicators. This makes it possible to generate a range of condition ratings depending upon the valuation of different users. We are exploring this approach as one means of integration of ecological, social, and economic conditions and values. These models are displayed visually, have feedbacks between different elements or indicators, and the inputs can be qualitative or quantitative, simple or complex. It is an approach that is readily transparent and facilitates dialogue and testing of different assumptions and viewpoints. An example that is also shown in Chapter 3, to illustrate the feedbacks between drivers and stressors, and ecological, social, and economic conditions is shown below.
vensimpic.png
Comment: This graphic seems to illustrate that everything is related to everything else (which is what ecology tells us, essentially), but we cannot be sure of its meaning otherwise. In a biological assessment, social considerations are only relevant as anthropogenic change, or changes to ecosystems that result from human activities. Anthropogenic impacts then are the spectrum of changes that have acted upon the ecosystem since approx. 1850 (or, going back further in time, highlight the beneficial impacts of Native American land management practices, and then discuss the impact that the departure of their influence has had on fire regimes). All of these can be enumerated and will be overlapping and will be cumulative.

In this assessment, the emphasis is on a limited set of meaningful, measurable indicators that vary with major ecosystem type (aquatic, riparian, and terrestrial). Wherever possible, indicators that have been identified in previous or on-going scientific studies or reviews have been included. The intent is to consider all sources of information and at this time to gather additional information that we may not have known about or thought to consider. Geographic data was prioritized.

There is a huge need for the Social Ecological Integration to apply environmental concerns and knowledge in positive way that helps all existing forms of recreation and land use to continue and flourish. A new way of thinking is needed based on dispersing use to reduce environmental impacts. Finding ways to keep existing routes and areas open to the public while addressing reasonable environmental issues. To address increased use by encouraging building new routes and allowing additional access to disperse and reduce impacts. This new way of thinking would benefit the public and the environment, rather than the current trend of using environmental issues as a club to further restrict land uses and thereby concentrating land use and needlessly harming the environment. (Road and Trail Change In Use Evaluation-California State Parks PEIR 2012 & USDA Forest Service 1996-National Off-Highway Vehicle Activity Review)


Incorporating future conditions into ecological integrity

To evaluate whether the "dominant ecological conditions" of an ecosystem can "withstand and recover from most perturbations" (quotes refer to planning rule definition of ecological integrity) it will be necessary to evaluate whether future conditions are likely to be different from the current and past and incorporate this potential for change (even if it lies outside the range of natural variability) into management planning. Climate change is and will continue to be a pervasive influence the function of ecosystems, and the Forest Service. Many tools are available for assessing such changes, including the California LCC Environmental Change Network (http://data.prbo.org/apps/ecn/) where maps can be generated to evaluate the distribution of current vs. future habitats, and the locations of areas which are likely to contain highest densities of priority conservation species targets (Figure XX). Specifically, it may be appropriate to recognize that certain vegetation types are likely to shift distributions 'upslope' to higher elevations where current and past climate conditions may be more similar in the future. This re-shuffling of the geography of habitats will create both a new landscape spatially, and new organization of important processes that shape the ecosystem (fire patters, precipitation patterns, timing of seasonal changes, species distributions, etc.).

Figure XX. Maps of current vs. projected future habitat type distributions and zonation analysis of priority avian conservation species targets. Maps were taken from the California LCC Environmental Change Network (http://data.prbo.org/apps/ecn/).

current future veg.jpg

ecn zonation.jpg


Literature cited:
Lindenmayer, D. B., Margules, C. R. and Botkin, D. B. (2000), Indicators of Biodiversity for Ecologically Sustainable Forest Management. Conservation Biology, 14: 941–950.

Rich, T. D., C. J. Beardmore, H. Berlanga, ... (2004). Partners in Flight North American Landbird Conservation Plan. Cornell Lab of Ornithology. Ithaca, NY.


Ecological/Geographic Variation and Assessment Stratification


Ecosystems and uses are not uniform across the bio-region. They vary from north to south, from east to west, with soil productivity, aspect, topographic position and climate that vary with elevation. For example, the southern Sierra Nevada reaches higher elevations and is drier (Figure x. Map of precipitation). Going north, precipitation increases to the west, but areas to the east become more prevalent on Forest Service units. There are also changes with increasing elevation that correspond with colder temperatures and shorter growing seasons. These are reflected in shifts in dominant and characteristic, plant, animal and other living things as well as characteristic fire patterns (fire regimes).


Figure x. Ecoregions, large landscapes with similar vegetation, soils, geology, climate, and topography. From Baileys xxxx.
modocpic.png
cascadepic.png
M261G-Modoc Plateau Section
M261D-Southern Cascades Section

sierrafoothillspic.png
snpic.png
M261F-Sierra Nevada Foothills Section
M261E-Sierra Nevada Section

monopict.png
sagebrushpic.jpg
341D-Mono Section
322A-Mojave Desert Section
*Also add 341F- nyo Mountains Section to Bailey's (above).
Broad zones that roughly correspond to elevational changes in climate and ecosystem composition (dominant plants and animals) were developed based upon the literature (i.e. Franklin and Fites-Kaufman 1996, Terrestrial Vegetation of California (Barbour et al. 2007). These include: foothill, lower montane and mid-montane, upper montane, subalpine and alpine zones. On the lee slope of the Sierra Nevada, the elevations tend to be higher because it is drier and colder.

FoothillEcological ZoneandTransitiontoMixed Conifer
foothills.jpg



Mosaic of Chaparral, Gray pine and grassland
Ponderosa pine/black oak

WestsideMontaneEcological zone
montane.jpg



Giant Sequoia
Ponderosa pine-mixed conifer
Douglas-fir mixed conifer




Upper MontaneEcological Zone
uppermontanechappic.jpg



Chaparral
Red fir
Jeffrey pine
Subalpine/AlpineEcological Zone
subalpinepics.jpg



Subalpine
Alpine

Eastside Ecological Zones




Sagebrush
Pinyon-Juniper
Yellow Pine
*In table above, list Eastside Ecological Zones in a similar way to westside, vs. lumping all as one
The framework for characterizing this ecological and geographic variation includes nested categories (Table x. )
Bio-Regional Assessment Subarea
Ecological Section (Bailey)
Dominant Vegetation Types/Zones
Azonal Types (with geo-graphic variation)
Administrative Unit
North
Modoc Plateau (M261G)
sage, pinyon-juniper, yellow pine, upper montane
Riparian, including meadows, and aspen (riparian and other)
Modoc
Sierra Nevada Foothills (M261F)
Southern Cascades (M261D)
sage, foothill woodland, hardwood, yellow pine, mixed conifer, upper montane, plantation
Lassen NF
Sierra Nevada (M261E)
Plumas
Central
Tahoe
foothill woodland, hardwood, yellow pine, mixed conifer, upper montane, subalpine, plantation
Eldorado
Yellow pine, mixed conifer, upper montane, subalpine/alpine
Lake Tahoe Management Unit
Plantation
Plantation
foothill woodland, hardwood, yellow pine, mixed conifer, upper montane, subalpine/alpine, plantation
Stanislaus
Southern
Sierra
Sequoia
Great Basin ?
Sage, pinyon-juniper, yellow pine, upper montane, subalpine/alpine, plantation
Inyo
In addition, a new ecological category will be addressed, the "conifer plantation" type which cannot be ignored from a scientific and ecological basis. The conifer plantation has not been described in any of the existing ecological frameworks and must be included as agriculture, or removed from the database for "mixed conifer." This is an important metric to understand, particularly as it relates to cumulative impacts on private lands, fire behavior, biological diversity and rare species habitat, and other effects/impacts.

Ecological-Cultural Relationships and Patterns

Native Americans have lived throughout the bio-region for thousands of years (see Chapter x). The people of various tribes have and now are tied to different ecosystems across the bio-region that basic life needs of food, shelter, and culture. It is not surprising that patterns of tribal distribution are concordant with different ecosystems in the bio-region. The map of tribal territories in the SNEP assessment shows that many of the larger areas representing tribal territories correspond with ecological subregions identified in the previous section. Tribes such as the Miwok and Maidu, that were and are distributed in the northern and central Sierra Nevada along the western slopes, coincide with dominantly mixed hardwood and conifer systems, where acorns are prevalent. The Mono and Washoe tribe lands coincide with the eastside ecosystems and subregions described here.
Map of Tribal territories of the Sierra Nevada ca. A.D. 1800
Ch1_SNEP_Tribal_Map_1800_small.png

There was and to a lesser degree currently is an interaction between Native American land uses and management and ecosystem condition and function. Native Americans often used fire or other means to tend basketry or food materials (Figure x), to improve habitat conditions for game species such as deer, and maintain meadow ecosystems. The Native American influence in the Sierra Nevada has been well documented by all relevant research and is not limited to riparian areas (Anderson and Moratto 1996).

See: Anderson, M.K.; Moratto, M.J. 1996. Native American land use practices and ecological impacts. In: Sierra Nevada ecosystem project: final report to congress, vol. II, assessments and scientific basis for management options, Ch. 9. Davis, CA: University of California, Centers for Water and Wildlands Resources: 1-20.

In riparian areas, a high proportion of plants that are important for basket weaving occur. These plants, such as willow, dogwood, or big-leaf maple, sprout following top removal. The stems grow straighter, with fewer insect nests, when they have been burned or cut. Although fire naturally occurred in riparian areas at different intervals throughout the bio-region, it is well documented that Native Americans supplemented lightning ignitions with targeted burning. Other species that require regular burning to maintain their viability and quality as weaving materials include beargrass (Xerophyllum tenax), deer grass (Muhlenbergia rigens), redbud, Ceanothus species, giant chain fern (Woodwardia spp.), and white root (Carex barbarae). There are other examples as well. Management for biodiversity, particularly through the use of beneficial fire, will help to maintain viable populations of the diverse plants and animals that are necessary for NA traditionalists to continue their cultural practices.

Figure x. Photos compiled by Dr. Frank Kanawha Lake, researcher at the US Forest Service Pacific Southwest Research Station and member of the Karuk tribe of northwestern California. Lower photos are from his doctoral research on traditional ecological management of riparian willows using burning for basketry materials. Upper photos are of Native American basket weaver and baskets. [Comment: need to add photos from Sierran tribes].
nativeambaskets.jpg

franklakepic.jpg


burnedwillowpic.jpg

Other Information Sources


Sequoia-Kings Canyon National Parks Natural Resource Condition Assessment

The Sequoia-Kings Canyon National Parks have completed an assessment on natural resource conditions within the two parks. The final report is currently being published. The NPS has provides the DRAFT report, but due to it's large size, it has been split into five parts.
Part 1 (Cover - 53; 12MB)

Part 2 (pages 54-143; 12MB)

Part 3 (pages 144-193; 7MB)

Part 4 (pages 194-269; 8MB)

Part 5 (pages 270-309; 3MB)


Conceptual Models for Key Ecological Integrity Indicators/Measures


A conceptual model of how key components and processes of terrestrial ecosystems interact was utilized to frame which indicators were important to assess. This is an approach recommended by Noon (2003) to develop ecosystem monitoring indicators. In adaptive management, there is a continual iteration of assessment, monitoring, and planning. It makes sense to apply the same conceptual model to the assessment as the monitoring phase. The intent was to develop a framework that is concise, and not overly complex, which highlights the most important conditions and processes that influence ecosystem function and services. Numerous conceptual models could be derived, and this one is meant to be simple, doable and based upon the history of management issues and concerns in the bio-region.

Conceptual models were developed for each of the major ecosystem types: aquatic, terrestrial, and riparian.

Due to the scope and extent of the ecological integrity of aquatic, terrestrial and riparian ecosystems, these subtopics were placed in separate sub-chapters on the WIKI.

[snapshot: 4/9/2013 @0931]



Bio-Region Aquatic Ecosystems

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF

Table of Contents

Sierra Nevada Bio-region
Chapter 1: Ecological Integrity of Ecosystems - Aquatic Ecosystems

Current Condition

Introduction

Water is the overarching environment of aquatic ecosystems. The quantity and quality of water influences the habitat conditions for the fish, insects, and other living things that occupy aquatic habitats, figure below. “Connected” or continuous the water flow is integral to the functionality of flowing water aquatic ecosystems, such as streams or rivers . For example, are fish able to migrate up and down a river or creek as needed to fulfill their life history requirements? Are large woody debris and sediment delivered, sorted and routed through stream networks at appropriate rates? Are water temperatures throughout the stream networks conducive to habitat needs of aquatic organisms?

Conceptual diagram of aquatic ecosystem components and interactions.
[Comment:
The meaning of all the arrows is not clear. Need to add dams and diversions.
Grazing, roads, mining, recreation, vegetation management all contribute to invasive species establishment; this graphic suggests that there are no causes, when in fact, invasive species are symptoms, not first causes, of ecosystem transformation/change/conversion. Also, pesticides and other pollutants are missing from graphic].

aqconceptual.jpg



Key Ecological Integrity Indicators/Measures

Ecological indicators of aquatic ecosystems include both abiotic (non-living), and biotic (living) components of ecosystems associated with water. The abiotic factors include those related to water such as water quality, water quantity and seasonal flow patterns. There are many different living organisms that occur in aquatic ecosystems but there are several that are the focus here because of their widespread use as indicators of ecological integrity (benthic macrointertebrates—insects), noted value to humans, are carnivores and have broad connectivity needs for population stability (fish), or are vulnerable to numerous stressors (amphibians-frogs and salmanders). There are other indicators that are useful integrative indicators of overall aquatic ecosystem function, such as the proper functioning condition rating used by the USFS that incorporates water, riparian vegetation condition, and erosion history and potential in the terrestrial landscape.

Based upon the conceptual model and available existing information, the following list of indicators and measures were selected.

Element/Function
Indicator
Measure
Source
Biological Integrity
macroinvertebrate composition
indices in wadeable perennial streams
SWAMP - CA database

fish populations: native, desirable non-native, invasive/nuisance,
geographic distribution & status
PISCES database (USFS)

amphibian populations
geographic distribution & status
SNAMP –Cathy Brown, CDFG, NPS, Amphibian Population Task Force

fish/amphibian condition
health (parasites, genetic deformities diseases eg. Chytrid))
SNAMP –Cathy Brown, CDFG, NPS
Water Quality
(see also Chapt. 2)
stream characteristics
woody debris, fine substrate, pool depth
NRIS

nutrient levels



water temperature

NRIS

% of water bodies
rating
CA 305b list, state water board

Pathogens
E coli, giardia, etc.
?

Chemical pollutants
Pesticides/herbicides, diesel oil, mercury, etc.
?
Water Quantity
flow characteristics
hydrograph
USGS, DWD
Process- Connectivity
(see also Chapt. 2, and Drivers and Stressors Chapt.)
ability to migrate (gene flow), energy to flow and nutrient cycling to occur
presence/abundance of dams, % of network connected
DWR database
Process - Energy flow & nutrient cycling
litter inputs from riparian hardwoods
fire presence/absence
FACTS or NFPLAN database, fire severity monitoring

algae
index
literature
Integrated biotic and abiotic integrity
watershed condition
index
DUBCAP

Current Condition: Aquatic Ecosystems


Water quality

The National Forests in California have generally provided a high level of protection for the Sierra Nevada headwaters. For example, a recent statewide survey found that streams in forested watersheds were in better condition than streams in watersheds in any other land use (Ode 2007). Water quality of the Sacramento River and its tributaries, which drain primarily NFS lands, have generally good quality and support their beneficial uses (Domagalski and others 2000). Sediment and nutrient loads from forested watersheds in the Sierra Nevada, including large areas within national forests, were found to be substantially lower than loads from downstream agricultural areas and significantly lower than average pollutant loads nationwide (Kratzer and Shelton 1998). Ahearn and others (2005) compared water quality in the upper Consumnes River watershed, which is mostly national forest, to the more agricultural and heavily populated lower watershed, and found that “upland drainages tended to deliver dilute, clear waters to the lowlands, while lower elevation sub-watersheds produced more turbid waters with elevated levels of constituents” (p. 242). Nevertheless, resource-management and protection activities on NFS lands have the potential to result in nonpoint source pollution of the State’s waters, and continual efforts are needed to maintain and improve water quality.

In the Sierra, aquatic ecosystems are recognized as being one of the most degraded of all ecosystem types (Centers of Water and Wildland Resources 1996). Fifty percent of native amphibians were already at risk of extinction well over a decade ago (Jennings 1996). Current trends suggest there is an urgent need to proactively address the threats to aquatic ecosystems throughout the Sierra Nevada in order to preserve the critical ecosystems, species and resources they support (California Trout 2008, Derlet et al, 2010).

Water quality impairments

Over 20 water bodies on NFS lands in the Sierra Nevada are listed as impaired on the State’s 2010 303(d) list. However, only Eagle Lake, the Truckee River, and Lake Tahoe and its tributaries are listed for pollutants related to silviculture and livestock grazing, such as sediment, nutrients, and pathogens. Most of the other listings are for mercury and other metals resulting from historic mining, natural sources, or unknown sources.
Comment: Need to define the 303(d) list specifically, and list the 20 impaired water bodies in a table, and identify the pollutants and pathogens.

Other water quality issues related to road density and stream sedimentation in this overview:


Related to livestock grazing:

(document uploaded by author)

Related to ecological influence of introduced non-native species in streams:

Influence of Introduced Non-Native Species on Stream Ecosystems:


Trout introduced into historically fishless headwater streams (Yosemite) reduce the diversity and abundance of native endemic invertebrates, and alter food web function and form. Removal of trout above natural barriers may permit recovery of some invertebrates.

Herbst et al. 2009 (and unpublished monitoring in Kings Cyn NP)
(document uploaded by author)


The New Zealand Mud Snail (NZMS) alters the energy flow and food web of invaded streams, competes with native algae-grazers and although it takes over ecosystem processes for a time, may also go through boom-bust phases where recovery to a natural state can occur.

Moore et al. 2012
(document uploaded by author)

NZMS cannot survive in streams of low mineral content, where conductivity is below 50 uS, so most mid-to-high elevation streams of the Sierra are not likely to be vulnerable to invasion.

Herbst et al. 2008
(document uploaded by author)

Hydraulic mining and mercury contamination

Kattelmann (1996) considered hydraulic mining to be one of the two largest human-caused effects on streams in the Sierra Nevada (the other was water development infrastructure). Geologic sources of mercury in the Sierra Nevada are limited to relatively small areas of metamorphic rocks formed from ancient sea-floor volcanic rocks. However, historic gold mining introduced large quantities of mercury into streams of the Northern Sierra Nevada in the nineteenth century. Miners used mercury to amalgamate and recover gold during placer (alluvial), hard rock, and hydraulic mining. The greatest amounts of mercury were used at hydraulic mines.

Alpers and Hunerlach (2000) determined a relationship between intensity of historic hydraulic mining in the Northern Sierra Nevada and mercury contamination, expressed as the mass of mercury per mass of tissues in aquatic organisms. In order of increasing mercury concentration, the major rivers of the Northern Sierra Nevada were ranked:

  1. American
  2. Feather
  3. North and Middle Yuba
  4. South Yuba and Bear

These streams are all currently listed as impaired owing to excessive mercury concentrations.

The total amount of mercury lost to the environment from mining operations in the late nineteenth century in the Sierra Nevada may have been 3 to 8 million pounds or more (Alpers and Hunerlach, 2000). Most of this mercury probably remains in the river beds of the Sierra Nevada.

Sediment yields computed from reservoir sedimentation rates (Chapter 8) are relatively low, and are well within the range for forested lands in the western United States as reported by Patric and others (1984). The mean of 0.82 tons per acre per year is higher than the average of 0.165 reported by Patric and others (1984), but lower than the range of 2 to 5 tons per acre per year suggested as acceptable for agricultural lands (Wischmeier and Smith, 1978). Patric and others (1984) suggested that a sediment yield of 0.25 tons per acre per year would be a good estimate for undisturbed forest lands. Twelve of the 16 sedimentation rates reported in Chapter 8 for NFS lands in the Sierra Nevada are less than this estimate, although the reservoirs are located within areas of actively managed forests.

Estimates of potential road-related sediment yields in the absence of BMPs were computed by multiplying road miles by road erosion rates, summing erosion for all 3 processes (road surface, gully, and landslide), and dividing the totals by the number of NFS acres (government-owned acres only) on each National Forest (Table 11). “Low” estimated sediment yields range only from 0.01 to 0.02 tons per acre per year, with a mean of 0.01 tons per acre per year. “High” estimated deliveries range from 0.07 to 0.19 tons per acre per year, with a mean of 0.12 tons per acre per year. Total estimated road-related sediment delivery for the 10 Sierra Nevada National Forests ranged from 111,000 to 1.3 million tons per year.

Water Quantity


Water availability for human uses in California is dependent on the total volume of water falling as precipitation but also on the timing of hydrologic processes such as snowmelt and streamflow. Annual precipitation and streamflow are useful measures for evaluating water resources, but the temporal distribution of streamflow is also important given the highly seasonal nature of rainfall and snowfall. High peak flows do not add substantially to water storage, and present hazards to life and property, whereas summer baseflows, although the lowest flows of the year, are critically important for human welfare and aquatic habitats.

Factors Influencing Stream Temperature


According to PNW research, the primary contributor to daily fluctuations in water temperature is direct solar radiation (Johnson 2004; Thomas 2005). Daily fluctuations in stream temperature correspond with daily fluctuations in solar heating (Stoneman and Michael 1996, Webb and Zhang 1997), with the warmest summertime stream temperatures typically occurring in mid- to late afternoon and the coolest summertime stream temperatures occurring near daybreak (Poole et al 2001). For many years, air temperature was thought to be a major factor influencing the water temperature in streams. However, heat budget analysis, using data from streamside climate stations, showed that direct solar radiation, not air temperature, is the largest contributor to changes in daily temperature (Thomas 2005). Riparian shade has a marked influence on stream temperature, particularly in terms of moderating diel temperature variation (Broadmeadow et al. 2011). Hynes (1960) showed that water temperature was dependent on many parameters, including the altitude and aspect of the stream. Other contributing factors include flow regulation at dams and diversions, groundwater effluents, channel geometry (width to depth ratio), streambed composition and the length of time water spends flowing through interstitial spaces in the substrate (hyporheic zone). Bedrock reaches have wide daily summer stream temperature fluctuations, with high maxima and low minima. In contrast, stream reaches with gravel bottoms and belowground flows tend to have a much narrower range of daily fluctuations (Thomas 2005).

Stream Temperature Importance to Ecological Integrity


Water temperature influences virtually every biotic component of stream ecosystems, from the emergence of caddisflies to the bacteria that cycle nutrients (Hawkins et al. 1997; Thomas 2005), and is one of the parameters in stream ecology that determines the overall health of aquatic ecosystems (Coutant, 1999). Water temperature plays a key role in determining the distribution of many aquatic organisms (Magnuson et al. 1979; Vannote et al. 1980; Ebersole et al. 2001), and is one of the most important environmental factors affecting fish (Fry 1967, 1971; Hutchinson 1976). For example, temperature regimes influence migration, egg maturation, spawning, incubation success, growth, inter- and intraspecific competitive ability, and resistance to parasites, diseases, and pollutants (Armour 1991). Most aquatic organisms have a specific range of temperatures that they can tolerate (Coutant 1977). Temperature has been a particular focus for salmonid fishes, due to their requirement for relatively cold water (Elliott 1981). Research has linked salmonid distributions to several gauges of stream temperature, including elevation gradients associated with climate (Fausch et al. 1994; Flebbe 1994), groundwater temperature (Nakano et al. 1996), and surface water temperature (Eaton et al. 1995; Torgerson et al. 1999). The latter most directly affects fish (Dunham 2001). The distribution of fish within a small area may be related to small gradients in surface water temperatures (e.g., Nielsen et al. 1994; Peterson and Rabeni 1996; Ebersole et al. 2001), but distributions on a larger scale may be indicated by broad-scale climatic gradients (e.g., Fausch et al. 1994; Rieman et al. 1997; Dunham et al. 1999). Warm water temperatures can decrease dissolved oxygen in the water and can act as a barrier to migration (CDFG 2010). Several diseases that infect fish are kept in check by cold water (Thomas 2005).

Dams and Flow Regulation Affects to Water Temperature


Reservoir construction and associated flow regulation modify the thermal regime of rivers, often with significant ecological repercussions (Webb and Walling 1996). Temperature and erratic flow fluctuations in dam tailwaters have altered phenologies of macroinvertebrates and fish, drastically reducing aquatic biodiversity in comparison to unregulated stream segments (Stanford and Hauer 1992). Dams directly affect downstream temperature; the type of effect depends upon the specific mechanism of water release (e.g., top or bottom release) (Poole and Berman 2001). Releases from the hypolimnion of reservoirs may completely prevent species from living in a stretch of river where they are normally found or cause a reduction in their relative abundance (Victoria EPA 2004). However, dams can be operated to provide desirable stream temperature regimes directly downstream through selective withdrawal of water from varying reservoir depths (Stanford and Hauer 1992). Flow regulation dampens variation in both flow and temperature (Poole and Berman 2001). hyporheic flow to act as a temperature buffer, differential storage of heat and water over time must occur. Differential heat and water storage are driven by variation in stream temperature and flow. Therefore, potential for hyporheic exchange to act as a temperature buffer is reduced by flow regulation (Ward and Stanford 1995).

Water withdrawals and diversions (i.e., for irrigation, municipal water supply, or hydropower) cause a reduction in river discharge, which has been shown to affect water temperatures (Cassie 2006). Sinokrot & Gulliver (2000) showed that the reduction of river flow greatly influenced thermal regime, specifically resulting in the increased occurrence of high temperature events. They also demonstrated that increasing river discharge in a regulated system would reduce the number of days that the water temperature exceeded a threshold value.

Coldwater releases from reservoirs can have a profound impact on the downstream thermal regime (Troxler & Thackston 1977). The main thermal effects of impoundment and flow regulation include elevated mean annual water temperature, depressed summer maximum temperature, delay in the annual temperature cycle, and reduced diurnal temperature fluctuation (Webb & Walling 1996). Webb & Walling (1993) also showed that temperature below reservoirs is modified most strongly in winter compared with the normal thermal regime, and winter freezing can be eliminated entirely. Winter water temperature increase could potentially have a greater impact on aquatic ecosystems (e.g. incubation of salmonid eggs) than that caused by summer conditions (Cassie 2006). Water releases have been noted to influence the growth rate of fishes downstream of reservoirs (Robinson & Childs 2001). Steady reservoir discharge in summer, at relatively constant cooler temperature, results in attenuated diurnal variations in downstream temperatures compared to normal (unregulated) flow conditions (Lowney 2000).

Water temperature in Big Silver Creek, Eldorado NF, summer 2002.The elevation of the Big Silver Creek monitoring station is approximately 1,485 meters (4,872 feet) above sea level. Figure 1 illustrates a typical summer water temperature regime for an unregulated stream. The stream in this example exhibits diurnal water temperature fluctuations of 5-7°C, a gradual warming trend throughout June, and seasonal maximum temperatures in mid-to-late July.
Chap1_Aqua_WaterTemp.JPG



Water temperature in Big Silver Creek, July 8-14, 2002. This figure illustrates typical diurnal summer water temperature fluctuations of 5-7°C in Big Silver Creek, a stream with unregulated flow. Note that the daily maximum temperatures occur between 16:00 and 17:00, and the daily minimum temperatures occur between 08:00 and 09:00. RAWS data from a station immediately east of the temperature monitoring site indicate that there was cloud cover that passed over the Big Silver Creek drainage, corresponding with the lower maximum water temperature on June 11, 2002.
Chap1_Aquatics_WaterTemp2.jpg


Bald Mtn Loc California RAWS data from July 8-14, 2002.
Bald Mtn Loc California RAWS
http://www.raws.dri.edu/cgi-bin/rawMAIN.pl?caCBAL
Total Solar Radiation
(langleys)
Average Air Temperature
(°F)
Max. Air Temperature
(°F)
Min. Air Temperature
(°F)
Total
Precipitation
(°F)

736.3
75
90
57
0

737.4
85.3
98
73
0

732.9
89.8
101
80
0

468.5
84.6
97
77
0

681.6
84.6
97
74
0

716.7
83.9
96
72
0

708.2
79.8
93
69
0



Water temperature in Warner Creek and Grassy Swale, June - August, 20011. The elevations of the Warner Creek and Grassy Swale monitoring stations are approximately 1,521 meters (4,991 feet) and 1,888 meters (6,194 feet) above sea level, respectively. These two monitoring stations are separated by approximately 17.5 km (10.9 river miles). Figure 3-1 illustrates a typical relationship between water temperature regimes in connected streams with unregulated flows. The streams in this example exhibits diurnal water temperature fluctuations of 6-8°C, a gradual warming trend throughout June, and seasonal maximum temperatures in late July. These paired sites exhibit the typical inverse relationship between elevation and water temperature; in unregulated systems, water temperature generally increases at lower elevations. Exceptions may occur where there is substantial flow contribution from groundwater sources such as springs. Note that there was a “low amplitude” anomaly (low diurnal fluctuation) on June 28, 2011 that contrasts the preceding and following days in the series. RAWS data from stations immediately east and west of these temperature monitoring sites (Table 2) indicate that there was a precipitation event and associated cloud cover that passed over the Warner Creek drainage on June 28, 2011. The solar radiation data correspond very closely with the water temperature pattern from June 27-June 30. NOTE: These detailed temperature records, along with stage-level discharge are derived from the sentinel stream network (David Herbst, SNARL, herbst@lifesci.ucsb.edu; se powerpoint under the Macroinvertebrate monitoring section below).
Chap1_Aqua_WaterTemp4.jpg


RAWS data from Lassen Lodge and Chester, California for June 27-30, 2011.
Lassen Lodge California RAWS
http://www.raws.dri.edu/cgi-bin/rawMAIN.pl?caCLAS
Top of Form
DateBottom of Form
Total Solar Radiation
(langleys)
Average Air Temperature
(°F)
Max. Air Temperature
(°F)
Min. Air Temperature
(°F)
Total
Precipitation
(inches)
6/27/2011
667.4
69.7
85
58
0
6/28/2011
135.7
54.5
61
50
0.41
6/29/2011
235.7
51.4
60
47
0.15
6/30/2011
676.3
61.5
76
49
0
Bottom of Form
Chester California RAWS
http://www.raws.dri.edu/cgi-bin/rawMAIN.pl?caCCHS
Top of Form
DateBottom of Form
Total Solar Radiation
(langleys)
Average Air Temperature
(°F)
Max. Air Temperature
(°F)
Min. Air Temperature
(°F)
Total
Precipitation
(inches)
6/27/2011
742
63
81
44
0
6/28/2011
132.5
51.1
59
46
0.48
6/29/2011
596.2
54.2
65
43
0.01
6/30/2011
708.7
57.1
77
39
0


Water temperature in the Tuolumne River near Mather, CA, July 14-20, 2009. The elevation of the Tuolumne River near Mather, CA is approximately 741 meters (2,431 feet) above sea level. As illustrated in Figure 4, the flow in the Tuolumne River near Mather is regulated by discharge from Hetch Hetchy Dam, 19.2 km (11.9 river miles) upstream. The summer water temperature pattern in the Tuolumne River at Mather exhibits the attenuation in diurnal variability (approximately 4° C) that is typical of flow-regulated streams where water is steadily released from the hypolimnion of a reservoir. At the point of release below Hetch Hetchy Dam, the water temperature is presumed to be fairly constant as long as the water column in the reservoir remains stratified. In this example the diurnal temperature fluctuations primarily result from exposure to solar radiation between the point of release (Hetch Hetchy Dam) and the monitoring station near Mather, CA - 11.9 river miles downstream. Diurnal maximum temperatures were recorded at 16:00, and diurnal minimum temperatures at 07:00, similar to unregulated flow conditions.
Chap1_Aqua_WaterTemp6.jpg

Water temperature in the Tuolumne River in relationship to pulsed flows from Cherry Creek, July 14-20, 2009. The elevation of the Tuolumne River at Lumsden Campground is approximately 430 meters (1,411 feet) above sea level. As illustrated in Figure 4, Lumsden Campground is approximately 9.5 river miles (15.3 kilometers) downstream from the temperature monitoring site at Mather, CA. However, the water-temperature signature in the Tuolumne River at Lumsden Campground (Figure 5) exhibits the influence of daily pulsed releases from Cherry Reservoir. Stream discharge (flow) data from Cherry Creek below the Dion R. Holm Powerhouse (above the confluence with the Tuolumne River) exhibit the daily pulsed releases from Valley Dam (Cherry Reservoir). As a result of these releases of cold water from Cherry Reservoir, the water temperature in the Tuolumne River 9.5 river miles (15.3 kilometers) downstream exhibits an abrupt 5°C drop daily between 10:00 and 13:00, a period of time when temperatures in unregulated flow conditions are warming. The delayed temperature response in the Tuolumne River is an artifact of the 11.9 km (7.4 river miles) distance between the Cherry Creek gauging station and temperature probe at Lumsden Campground. Also note that the maximum daily water temperatures at Lumsden Campground are approximately 2-3°C colder than at the Mather monitoring site upstream (Figure 4-1), which is approximately 1,000 feet higher in elevation.
Chap1_Aqua_WaterTemp7.jpg


Water temperature in the S.F. American River below Slab Creek Reservoir, June-August, 2002. The elevation of the monitoring station in the S.F. American River below Slab Creek Reservoir is approximately 500 meters (1,640 feet) above sea level. Figure 6 illustrates a typical summer water temperature regime for a regulated stream near the point of release. The S.F. American River temperature monitoring site is approximately 375 meters downstream from Slab Creek Dam. The stream in this example exhibits attenuated diurnal water temperature fluctuations of approximately 1°C throughout the summer, a rapid warming trend in the last two weeks of June, and seasonal maximum temperatures in late June. Note the low seasonal maximum water temperature in this example (17.2°C), which appears to be incongruous with the relatively low elevation of the site on the S.F. American River.
Chap1_Aqua_WaterTemp8.jpg

Chap1_Aqua_WaterTemp9.jpg
Water temperature in the M.F. Cosumnes River and Cat Creek, June-August, 2011.
Chap1_Aqua_WaterTemp10.jpg



The elevations of the M.F. Cosumnes River at PiPi Campground and Cat Creek monitoring stations are approximately 1,175 meters (3,855 feet) and 1,667 meters (5,469 feet) above sea level, respectively. As illustrated in Figure 7, these two monitoring stations are separated by approximately 13.6 km (8.5 river miles). Figure 7-1 illustrates the combined influence of a melting snowpack and groundwater (springs/seeps) on water temperature regimes in connected streams with unregulated flows. The streams in this example exhibit diurnal water temperature fluctuations of 3-4°C in June, a gradual warming trend throughout June and July, and seasonal maximum temperatures in August. These paired sites also exhibit the typical inverse relationship between elevation and water temperature in late July and August. Water temperature generally increases at lower elevations in unregulated systems. However, there is substantial overlap in the temperature regimes of these two sites during late June and early July, followed by divergent temperature profiles from mid-July through August. This divergence is accompanied by greater attenuation of the diurnal temperature fluctuations in the M.F. Cosumnes River in comparison with Cat Creek. This attenuation is the result of flow contribution from groundwater sources such as springs. During the early summer (June), the groundwater influence is masked by flow contribution from the melting snowpack via Cat Creek and other tributaries. In early July, the predominant flow contributions to the M.F. Cosumnes River transition from surface to groundwater. As long as flow is snow-melt dominated, the stream temperature variation is more strongly correlated with solar radiation and air temperature. When the snowmelt recedes, groundwater dominates the stream discharge and the water temperatures become more decoupled from solar radiation and air temperature. NHD point data plotted in Figure 7-1 indicate seven mapped springs that contribute flow to the M.F. Cosumnes River upstream from PiPi Campground. Spring data are not comprehensive in NHD. Therefore, there may be additional (unmapped) springs contributing flow to the M.F. Cosumnes River.
NOTE: These detailed temperature records, along with stage-level discharge are derived from the sentinel stream network (David Herbst, SNARL, herbst@lifesci.ucsb.edu; se powerpoint under the Macroinvertebrate monitoring section below).


Aquatic Ecological Characteristics: Water Quantity


Water availability for human uses in California is dependent on the total volume of water falling as precipitation but also on the timing of hydrologic processes such as snowmelt and streamflow. Annual precipitation and streamflow are useful measures for evaluating water resources, but the temporal distribution of streamflow is also important given the highly seasonal nature of rainfall and snowfall. High peak flows do not add substantially to water storage, and present hazards to life and property, whereas summer baseflows, although the lowest flows of the year, are critically important for human welfare and aquatic habitats.

Annual precipitation and streamflow


Annual amounts of precipitation and streamflow are fundamental to assessing water resources on the Sierra Nevada National Forests. In this section, we present records of precipitation and streamflow provided by the National Weather Service, DWR, and USGS to help in evaluating conditions and trends. It is important to note that global climate change is expected to affect temperature, and hence the ratio of snow to rain, more than the total amount of precipitation (California Department of Water Resources, 2008).

As shown in Chapter 8, annual precipitation in the Sierra Nevada varies considerably. Maximum annual precipitation has been roughly 5 to 6 times higher than minimum annual precipitation over the past half century. No general trends in total precipitation are obvious, but warmer temperatures have increased the proportion of rain and decreased the proportion of snow in annual precipitation totals at mid-elevations (DWR, 2008).

The double-mass curves for stations on or near NFS lands (Chapter 8) all show subtle and alternating short-term trends in the past 50 years toward both slightly increased and decreased streamflow per inch of rainfall. The double-mass curve for the Merced River in Yosemite National Park is noticeably straighter than the curves for the stations on NFS lands. This may be an artifact of the different land management activities in the parks and forests, or other factors may be responsible.

Peak flows


Major floods during the historic period in the Sierra Nevada occurred in 1861-62, 1906, 1909, 1955, 1964, 1986, 1997, and 2005. Based on these dates, the frequency of large floods may be increasing. However, graphs of peak flows at USGS gaging stations in the Sierra Nevada do not suggest any systematic trends toward higher annual peak flows in the past 50 to 100 years (Chapter 8).

Ecological effects of rain-on-snow floods in headwater streams
: (document uploaded by author)

Rain-on-snow winter floods are one manifestation of climate change and studies of intact headwater stream habitats before and after the record winter flood of 1997 showed no changes in the invertebrate community. In contrast, most streams already disturbed by livestock grazing became dominated by opportunistic species and shifted to a more detritus-based food web structure. Intact headwater streams are habitat refuges.

Duration of baseflows


Baseflows are streamflows supplied by gradual discharge of groundwater and soil moisture to streams in periods between rainstorms or snowmelt periods. Baseflows are critical in California owing to the highly seasonal climate, in which almost all precipitation and snowmelt occurs between fall and late spring, and water demand for irrigation is highest during the summer. Summer baseflows are likely to be affected by changing climate owing to warmer temperatures that reduce snowpack and advance snowmelt.

Rough estimates of current baseflows were made by computing ratios of mean summer (July 1 to September 30) streamflows to mean annual streamflows for each year of record for 5 long-term USGS gaging stations on streams in the Sierra Nevada that are not regulated or diverted (Chapter 8). Although substantial regional variation is apparent, no clear trends in the proportion of streamflow occurring during the summer months are obvious.

Dams and reservoirs


Dams and reservoirs are one of the two most significant impacts to streams in the Sierra Nevada (Kattleman, 1996). All major rivers in the Sierra Nevada are impounded and regulated to some extent, with the exception of the Consumnes River. According to the Mountain Counties Regional Report in the 2009 update of the State Water Plan, a total of 76 reservoirs are located within the mountain counties (Plumas to Sequoia Counties). The reservoirs range in size from 0.0003 to 3.54 MAF, and total capacity of these reservoirs is 17.4 MAF.

Aquatic Ecological Characteristics: Fish


Approximately fifty kinds of fish are native to the Sierra Nevada; eleven of these taxa are found only in this range. The fish fauna and fisheries of the Sierra Nevada have changed dramatically since the massive influx of Euro-Americans began in 1850. Four broad patterns are evident:
  1. anadromous fishes, especially chinook salmon, have been excluded from most of the riverine habitat they once used on the west side of the range;
  2. most resident native fishes have declined in abundance, and the aquatic communities of which they are part have become fragmented, although a few species have had their ranges greatly expanded;
  3. thirty species of non-native fishes have been introduced into or have invaded most waters of the range, including extensive areas that were once fishless, mainly at high elevations; and
  4. Sierra Nevada fisheries have largely shifted from native fishes, especially salmon and other migratory fishes, to introduced fishes.

One reflection of these patterns is that of the fifty fishes native to the Sierra Nevada, ten (20%) are formally listed by the federal government as threatened or endangered species, 5 (10%) are in danger of extinction in the near future, ten (20%) are on a trajectory toward extinction if present trends continue, and fifteen (30%) are in long-term decline or have small isolated populations, but do not face extinction in the foreseeable future. The remaining 10 (20%) are of least concern (Moyle et al. 2011). Among the species that have largely disappeared from the range are Chinook salmon, steelhead, and five kinds of native trout. Fisheries for these species have been replaced, in part, by stream fisheries for nonnative trout, often of hatchery origin, and by reservoir fisheries. The introduction of trout into several thousand originally fishless lakes at high elevations has greatly expanded fishing opportunities but has also caused declines of native invertebrates and amphibians. Introduction of non-native fish species has also been the single biggest factor associated with fish declines in the Sierra Nevada. However, this factor is intimately tied to major habitat changes and other effects of dams and diversions, as well as habitat changes caused by a variety of streamside activities (Moyle et al. 1996). Fragmentation to fish and other aquatic habitat is addressed in Chapter 3, Drivers and Stressors.

Aquatic Ecological Characteristics: Amphibians


Despite over 300 million years of existence on Earth, more than 168 species are believed to have gone extinct in the last two decades and a further 43 percent of those remaining are in decline (AmphibiaWeb 2009). Habitat destruction, global climate change, introduced species, over-exploitation, UV-B radiation, chemical pollutants and emerging diseases appear to work synergistically creating a negative spiral for amphibians (AmphibiaWeb 2009).

This assessment focuses on high elevation Sierra Nevada stream, lake and meadow habitats, those most sensitive to effects of climate change and shifting seasonality of precipitation. Amphibian species included are primarily those with known restricted or recently contracted distributions and populations including: mountain yellow-legged frog (MYLF), Sierra Nevada mountain yellow-legged frog (SNMYLF), Cascades frog (RACA) and Yosemite toad (YOTO).

Amphibian characteristics by: types of characteristics and applicable species, landscape scale of the characteristics, how the characteristic is measured, and the source of the characteristic’s information.
Habitat Characteristics
Scale
Measures
Info Sources
Population Distribution - MYLF, SNMYLF, RACA, YOTO
Bioregional, Forest
Number of Populations, Acres Inhabited
R5 Monitoring, CDFW Basin-wide Surveys,
Population Abundance - MYLF, SNMYLF, RACA, YOTO
Bioregional, Forest
Estimated Numbers
R5 Monitoring, CDFW Basin-wide Surveys
Number & Ac Ft. Historically Fishless Lakes & Streams
Bioregional, Forest
Number pre-European Lakes/Streams (or drainage basins?), Acre Feet
CDFW Basin-wide Surveys
Number & Ac Ft. Currently Fishless Lakes & Streams
Bioregional, Forest
Number of Current Fishless Lakes/Streams (or drainage basins?), Acre Feet
CDFW Basin-wide Surveys
Distribution & Abundance of Bullfrogs
Bioregional, Forest
Number of HUC-6 Watersheds with known Bullfrog Presence
PSW & Academic Research, CDFW


How Amphibian Habitat Characteristics Were Selected & Why


The most basic criteria employed in selecting these characteristics is that they are 1) measureable, 2) data are available, and 3) tell us something important about amphibian populations and habitat. The premise underlying most of these measures is that small, isolated populations have less ability to survive and recover from random environmental events such as fire, disease, drought, etc.
  • Population Distribution of 4 Rare Species–Sodhi et al. (2008)evaluated a large body of world-wide amphibian decline literature (2,583 species) to reach the conclusion that species with limited (small) geographic range are most likely to experience severe decline as a result of greater habitat specificity in their life cycles. Therefore, broader distributions are preferred.
  • Population Abundance of 4 Rare Species– Chytrid research has demonstrated that large populations have better ability to persist following high level infections that kill many if not most individuals (Knapp et al. 2011). Large populations are better.
  • Number and Acre-Feet of Historically Fishless Lakes – Among the primary extinction drivers acting upon amphibians in the world today (chytrid, introduced fish, climate change, habitat loss), the broad-scale introduction of non-native and native trout into historically fishless lakes has significant negative effects on amphibians there (Pope and Long 2013). More was better.
  • Number and Acre-Feet of Currently Fishless Lakes – As above, and the more as a percentage of historic condition, the better.
  • Distribution and Abundance of Bullfrogs – A predator and competitor, this non-native invasive species has been moving into habitat and out-competing native amphibians as well as aquatic reptiles.

Current Condition of Amphibian Species and Habitat

  • Current Distribution relative to HistoricIn general, the distributions of these four high-elevation species are greatly contracted due to changing climate conditions, chytrid-induced die-offs, and habitat lost to introduced native and nonnative predators.
  • Population In general, the abundances of these four high-elevation species have significantly declined due to changing climate conditions, chytrid-induced die-offs, and habitat lost to introduced predators. Effects of UV-B radiation, and habitat loss due to human causes have also been implicated in the literature (Sodhi et al. 2008).
  • Habitat StatusMore potentially suitable habitat exists than is currently occupied by these species.

Amphibian Trends Under Current Management

  • Population–It is currently unclear whether current management in the form of roads, activities such as meadow trails, etc. are making a significant contribution to the over-arching major stressors described above. These major stressors are anticipated to continue to drive the populations toward an extinction vortex. It may be the best we can hope for as managers to is slow the process enough to allow science to find ways to conserve species and mitigate these stressors. Solid data back this declining trend and our level of certainty is high.
  • HabitatImproving as more introduced fish are no longer stocked into high mountain lakes or are actively removed. Improving management activities to restore hydrological function and restore water tables may also improve conditions, but it is too soon to tell whether these positive effects will be swamped by the global forces. The ability to discriminate trends from NFS management actions as opposed to global processes is low.

Amphibian trend monitoring within the Sierra Nevada Bio-region.
Trend Assessed
Key Management Question
Lead Proponent
Research
Model
Strategy
Changes in Population Distribution - MYLF, SNMYLF, RACA, YOTO
Have any of these distributions decreased?
R5 Monitoring coordinator, Research
X


Changes in Population Abundance - MYLF, SNMYLF, RACA, YOTO
Have populations of any of these 4 species decreased?
R5 Monitoring coordinator, Research
X


Change in Number & Ac Ft. of Fishless Lakes & Streams – Historic to Present
Have we decreased the number and ac-ft of fishless lakes & streams?
CDFW & Forests

Map

Changes in Distribution and Abundance of Bullfrogs
Has the distribution or abundance of bullfrogs increased?
R5 Monitoring coordinator, Research
X




Macroinvertebrates and Algae Monitoring Methods


To assess the biological water quality of streams, rivers and lakes in the Sierra Nevada national forests, and reach statistically valid conclusions about the overall quality of biological water resources on these forests requires considerable sampling effort because of the sheer size (more than 4 million hectares or 10 million acres) and highly variable topography. This broad-scale assessment is possible by application of a design based on probabilistic sampling (Stevens and Olsen 2003, 2004, Olsen 2008a, b), which is basis for monitoring in the Sierra Nevada national forests. Examples of such probabilistic monitoring plans are provided by State of California’s Perennial Stream Assessment (PSA) program (Ode et al. 2011) and Clean Water Act 305(b) Report (SWAMP 2006) assessing the state of the States waters. EPA EMAP’s stream and lake monitoring program has also been applied across the entire contiguous United States (EPA 2006, 2009).

Since the State’s PSA and the Forest Service’s Management Indicator Species (MIS) monitoring programs both utilize a probabilistic sampling with common design features, it was possible to combine the data from both programs to form a more robust evaluation. Stream and river sites were chosen from the National Hydrography Database (NHD) for 2nd through 4th- Stahler order perennial streams. Since the length of lower order streams far exceeds that of higher order streams, a random sample will select far more small streams compared to large ones. To compensate for this unequal representation resulting from a random sample and make sure that larger, 4th-order streams were adequately sampled, an equal number of sites from each of the three stream orders were targeted for sampling (Olsen 2008a).

Prior to deciding to sample a site, a map reconnaissance was conducted to assure access and appropriateness of the site for sampling. If a site was judged inaccessible due to extreme distance (> 7 miles from the trailhead), treacherous or unsafe terrain, or inappropriate for sampling because of significant activities not representative of national forest management like major water diversions, extensive private land in close proximity or flow manipulations not under the jurisdiction of the Forest Service, it was removed and another randomly selected site was substituted for it. The sample size was not large enough to evaluate trends in condition over the period of collection from 2000-10. In cases where multiple samples had been taken at a site using different collection methods (e.g. reach-wide vs. targeted riffle) or over two consecutive years, the average of the scores was used to represent the site.

Site condition scores were calculated using two models. The first utilized a multivariate RIVPACS (RiverInVertebratePredictionAndClassificationSystem) model developed under several contracts with the USFS Regional Office (Hawkins et al. 2000, Ode and Schiff 2009, Ode et al. 2011). The second model, a multimetric Index of Biotic Integrity (IBI) model developed for hydropower related impacts for the western Sierra Nevada region (Rehn 2009), was also utilized. The metrics developed to determine hydropower effects are robust and sensitive to a variety of impacts, so they are appropriate for evaluating impacts from a variety of stressors associated with land management activities.

To calculate a final site condition score, the average of the RIVPACS Observed-to-Expected (O/E) and IBI score for each site was calculated. IBI scores, which may range from 0-100% were standardized to unity by dividing each score by the mean score (i.e. 74) for reference sites in the entire State-wide PSA data set. It is believed that the average of these two models provides a more reliable assessment of stream conditions than either one individually.

According to the probabilistic sampling design, each site sampled represents a specific and variable perennial stream length (from 7 to 322 kms for this data set). Therefore, it was necessary to weigh the contribution of each sample site to the entire assessment by summing the weights for all sites falling into each condition category. Since two probabilistic designs (i.e. PSA and MIS) were united, it was necessary to recalculate and assign new weights based upon the new combination of 74 sites. Once the weights had been recalculated, the sum of weights for all sites in each condition category was determined. The result was an estimate of the total length of perennial stream in each of four condition categories: sites with scores greater than 0.85 were considered to be in excellent condition, sites scoring between 0.70-0.85 were in good condition, sites scoring between 0.55-0.70 were poor, and sites scoring less than 0.55 were very poor. Sites scoring in the excellent-good categories were considered comparable to reference or undegraded conditions; sites scoring as poor to very poor (less than 0.70) were considered degraded.

The ecological interpretation is that the threshold for degradation is 0.70. This means that less than 70% of the biological community expected to occur there in the absence of degrading impacts were actually observed; the habitat is not of sufficient quality to support the 30 percent of taxa that are missing.

Macroinvertebrates and Algae Assessment Programs

Assessments of Algae and Macroinvertebrate communities for aquatic ecosystem health are conducted by both state and federal programs. The sentinel stream network for detecting climate change effects on headwater ecosystems was established in 2010-2011-2012, collecting data from 24 streams in 7 National Forests and 3 National Parks in the Sierra. This adds to the assessment capacity for Sierra Nevada stream integrity and can be viewed here in more detail in a powerpoint presentation.
(uploaded by author)

Forest Service Management Indicator Species (MIS) Program

Approximately 290 invertebrate taxa were identified in collections from the 21 MIS stream and river sites, four of which were revisited. More than 15,000 specimens were identified; non-biting chironomid midges were the most abundant taxon with about 27% of the total. Mean taxa richness per site, a sensitive indicator metric, was 40, but varied widely from 9 for Greenhorn Creek, Tahoe National

Photographs from selected aquatic MIS sites: A) Willow Creek, Plumas National Forest- Score of 0.26; B) Greenhorn Creek, Tahoe National Forest- Score of 0.47; C) North Fork Tuolumne River, Stanislaus National Forest- Score of 0.90; and D) Jawbone Creek, Stanislaus National Forest- Score of 0.98. Sites A and B were in the very poor or degraded category. Note the poor development of riparian vegetation and uniform channel type without pool development. Sites C and D were in the excellent category. Note the variety of channel types, substrate sizes and well developed riparian vegetation. Coarse woody debris, which provides cover and channel stability, is also prominent at Jawbone Creek.

Chap1_Aqua_AquaticMIS.jpg





























State Perennial Stream Assessment (PSA)
The State’s Perennial Stream Assessment monitoring provided data from 53 sites. Thirty-nine of these sites had multiple scores because samples were collected by alternative protocols (e.g. targeted riffle vs. reach-wide; Rehn et al. 2007, Ode et al. 2011), so that the results from both collection methods could be compared for the State’s program development. For sites with multiple samples, the average site condition score was used.
Combined Results of Macroinvertebrates and Algae Assessment ProgramsThe data from the 21 MIS sites collected from 2009-2010 and 53 PSA sites collected from 2000-2010 were combined to cre a ize of 74 randomly selected sites scattered across the 10 national forests in the Sierra Nevada bioprovince (Figure 2). Overall, 35 sites or 46 percent were in excellent condition, 19 percent were good, 20 were poor and 15 percent were very poor. This means that 65 percent of streams were in reference (excellent-good) or undegraded condition and 35 percent were degraded (poor-very poor). When the sums of weights associated with the sites were calculated, 5,692 km or 78 percent of the 7,300 km of stream length assessed were in excellent-good condition, and 1,608 km or 22 percent were in poor-very poor condition (Figure 3). The total length of 2nd through 4th- Stahler order perennial streams on the Sierra Nevada national forests is 11,185 km or 6,950 mi. Therefore, the 74 sites sampled represent 63.3 percent of the entire perennial stream length (7,300/11,185 km) (Figure 4). A majority of the sites (54 percent) fell in the excellent condition category. The scores for sites collected by the Forest Service’s MIS program were better than those collected by the State PSA program.
Chap1_Aqua_AquaticMIS01.jpgDistribution and condition of 74 probabilistic bioassessment sites, 21 from the Forest Service Management Indicator Species (MIS) program and 53 from the State’s Perennial Stream Assessment (PSA) program. Site conditions were determined by averaging RIVPACS O/E and hydropower IBI scores
. Chap1_Aqua_AquaticMIS02.jpg
Percentages of perennial stream miles scoring in different condition categories. Overall, about 78 percent of all perennial stream miles were in reference (i.e. excellent to good) condition and 22 percent were degraded (poor to very poor) condition.
Chap1_Aqua_AquaticMIS03.jpg

Percentage of stream miles in each bioassessment condition class. The total distance of 2nd through 4th- Stahler order perennial streams on the Sierra Nevada national forests is 11,185 km or 6,950 mi. The 74 PSA and MIS sites represent a sample of about 65 percent of the total perennial stream distance in the Sierra Nevada Bioprovince. Overall, 47.8 percent of the all perennial stream miles in the Sierra Nevada Province and 78 percent of all stream miles surveyed were in reference (excellent-good) condition. About 17.5 percent of all perennial stream miles or 22 percent of surveyed stream miles were degraded (poor-very poor condition). Unevaluated sites were those not sampled because of extreme distance, treacherous and unsafe terrain, or presence of significant activities not representative of national forest management like major water diversions, extensive private land in close proximity or flow manipulations not under the jurisdiction of the Forest Service.
Lake Aquatic Management
A total of 114 aquatic invertebrate taxa were identified from collections at the 10 lake sites collected during 2009-2010; six of which were collected both years. Mean taxa richness was 17 and varied from a low of only 3 at Gilmore Lake on the Tahoe National Forest to 53 at Clear Lake on the Modoc National Forest, both in 2010. Estimated mean density of macroinvertebrates was 445 per m2 (range from 7 at Miller Lake in 2010 to 2,133 at Clear Lake in 2009). At present there are no accepted methods for evaluating lake condition based upon benthic macroinvertebrates alone so further conclusions are not yet possible.

It is noteworthy that Clear Lake on the Modoc National Forest had the highest species richness (53 invertebrate taxa) because it is the headwaters for the Lost River. Clear Lake and the Lost River are occupied by a genetically distinct population of Sacramento perch that was introduced by CDFG during the 1960s (Moyle 2002). The Sacramento perch Archoplites interruptus is the only native member of the family Centrarchidae west of the Rocky Mountains and has been almost entirely displaced from its native range in the Central Valley by centrarchids introduced from the eastern United States. Moyle et al. (2011) consider this species to be in danger of extinction in the near future if present trends continue.

Algae Monitoring Results

Diatoms and soft-bodied algae were collected at all stream sites during 2009-10 according to the standard SWAMP protocol (Fetscher et al. 2009). A total of 600 diatom valves were counted for each sample. Currently there is no formally established lab taxonomic standard protocol or data format to store the data collected.

The current SWAMP protocol for sampling stream algae includes methods for both diatoms and soft-bodied algae. Both algal types were collected during 2009. However, only diatom samples were collected during 2010 because of unreconciled issues over replicability of the soft-bodied algae protocol, and concerns about safety in the field regarding the handling of gluteraldehyde, which is a highly toxic preservative. Thus far about 220 algae taxa have been collected. Some diatom taxa appear to be ubiquitous and have occurred at every site (i.e. Encyonema silesiacum , Synedra ulna and pennate diatoms). Algae are proving to be sensitive habitat gauges of water quality, especially water chemistry attributes such as nitrate concentrations, which are associated with eutrophication (Blinn and Herbst 2003, 2007).
Conclusions from Macroinvertebrates and Algae Assessment Programs
In summary this is a preliminary compilation for biodiversity and bioassessment of aquatic resources of the Sierra Nevada Province. Overall, the percentage of stream sites meeting the objectives of the Clean Water act (i.e. reference condition, meaning they were judged to be in good to excellent condition) was estimated to be about 78% according to the combined multivariate RIVPACS and hydropower IBI models.

The estimate of about 78 percent of perennial stream miles in reference condition is fairly consistent with previous such estimates. The California State Clean Water Act 305(b) report (SWAMP 2006) concluded that about 67% of perennial stream miles in California were in reference or non-impaired condition. Ode et al. (2011) estimated that across the entire State, which included forested, urban and agricultural land use, only about 50% of perennial streams were considered to be in reference or unimpaired condition. For the Sierra Ecoregion, Ode et al (2011) calculated that about 65 percent of the perennial stream miles were in reference condition, which is lower than the combined MIS-PSA data set for the Sierran national forests.
Macroinvertebrates and Algae Science Synthesis
The following sections come directly from one of the draft Science Syntheses posted on the PSW website, Chapter 6.1 Watershed and Stream Aquatic Ecosystem (2013). At this time, it was not possible to summarize or paraphrase this critical piece of work, since we just received them. However, given the importance of the topic and varying inferences on effects to management, it is critical that the information be included for purposes of dialogue.

Excerpted from PSW Science Synthesis, 6.1 Watershed and Stream Ecosystems (2013) by Carolyn Hunsaker and Jonathan Long with contribution from David Herbst

“Natural patterns of variation in stream communities in space and time
Carter and Fend (2001) found that differences in the richness of invertebrates in riffle and pools appear to depend on annual discharge regime, and are more pronounced during low discharge years and disappear when flow is higher. This study, which took place on the Merced River in the Yosemite Valley, suggests that differences in erosional and depositional features between riffles and pools diminish when flows increase, so communities become more similar. An implication of this is that it is possible that flow regulation may influence the natural variations in habitat-based diversity and that channelization (eliminating riffle-pool geomorphology) may also produce less diverse assemblages of aquatic life and more limited ecosystem processes (such as nutrient recycling, productivity, organic matter transport, conversion, and decomposition). Beche and Resh (2007) found that traits related to adaptations to the environment vary in response to gradients of flow between years, from dry (drought) to wet (above average) conditions. Traits that provide adaptation to drying (e.g., desiccation resistance, aerial respiration) were more common in drought years, whereas traits permitting survival during high flows (e.g., flat body shape, drift dispersal) were more common in wet years. Prolonged drought or wet conditions result in shifts in trait composition. Despite this, there is redundancy in traits among taxa, so taxa can be replaced without loss in represented trait diversity. This suggests that it may be more difficult to conserve species diversity than trait diversity in the face of changing climate regime.
Erman (2002) studied the invertebrates of spring and springbrook (outflows) communities over 20 years to describe the biota and physical/chemical properties of Sierra Nevada cold springs. Results showed the individualistic nature of springs even within the same stream basin. Spring invertebrate assemblages differed greatly from one spring to another, as did timing of insect emergence and abundance of species. Invertebrate species richness was greater in deeper, more permanent springs, which were distinguished by high concentrations of dissolved ions, especially calcium. Spring permanence was also determined by direct observations over time, measurement of discharge variability, correlation of discharge with ionic concentration, and water dating. This study shows the high conservation value of spring habitats and the high levels of diversity that can serve as a biodiversity refugium in cold-water environments.”

During 2007 and 2008, 38 stream reaches in the Sierra Nevada and Southern Cascade Ranges, CA, were sampled for aquatic macro-invertebrates. These sites were simultantously sampled for meadow vegetation condition, greenline vegetation condition, and physical stream measurements using a modified Stream Condition Inventory (MSCI) to measure stream temperature, width-depth ratios, and mean bank angle (see attached document on Using aquatic macro-invertebrates as bioindicators and the relationship to livestock grazing in the Sierra Nevada and Southern Cascades Ranges, CA. Rosgen stream type was also determined for each site. A RIVPACS (River In Vertebrate Prediction and Classification System) bio-indicator score was calculated for each reach based on the presence of aquatic macro-invertebrates and each of the 38 reaches was determined to be either at reference of impaired condition based on the RIVPACS bio-indicator score. The areas sampled were on active grazing allotments administered by the US Forest Service and these sites are part of the USFS Region 5 Long Term Monitoring Project.
Results of the study indicate:
  1. meadow condition and greenline condition was not different between reference and impaired reaches as indicated by the RIVPACS bio-indicator score.
  2. Results indicate that a very weak positive relationship (P < 0.20) may exist between the greenline vegetation score and RIVPACS bio-indicator score and more studies are needed to confirm this.
  3. Mean bank angle, and overall indicator of stream channel functioning, was different between reference and impaired reaches as indicated by the RIVPACS bio-indicator score.
  4. Rosgen stream type was related to mean bank angle, meadow condition, and channel width to depth ratio therefore Rosgen stream type is an important factor in assessing bank angle and condition metrics.
  5. Rosgen stream type should be accounted for when making assessments of stream condition using macro-invertebrates as biometrics, and reference systems for scoring, such as RIVPACS, should be stratified by Rosgen type when making stream assessments.

This is a brief write-up about this study.


Fire effects
Beche et al. (2005) found minimal effects from prescribed fire on stream invertebrates in a Sierra Nevada study. Prescribed fire altered BMI community composition only within the first weeks post-fire, but there were no lasting (1 year) impacts on BMIs. Densities and percentage of sensitive taxa were significantly reduced after an intense wildfire on Angora Creek in the Lake Tahoe Basin, but there were no consistent changes in taxonomic richness or diversity (Oliver et al. 2012). Canopy cover and bank stability declined dramatically following the wildfire and substrate also changed substantially, with fine sediment more abundant and cobble less abundant post-fire. There were large reductions in relative abundances of shredder and scraper taxa, whereas collector-gatherer abundances increased. Community composition shifted away from pre-fire configurations, and continued to diverge in the second year following the fire. Scores from a regionally derived index of biotic integrity (IBI) were variable, but overall they were much lower in post-fire samples and did not show recovery after 2 years. This study demonstrated substantial post-fire effects to aquatic ecosystems even in the absence of large flooding or scouring events, and it showed that these effects can be transmitted downstream into unburned reaches. These findings, when compared to those from Beche et al. (2005), suggest that fire effects are strongly related to fire intensity.”
Forest management practices
“Although stream invertebrates have been an MIS for the Forest Service, little published information exists regarding effects of mechanical forest management practices (road building and maintenance, tree thinning and commercial harvesting, tractor piling of slash and burning) on stream invertebrates in the Sierra. A few publications exist on prescribed fire effects on stream invertebrates (see previous discussion). The usefulness of stream invertebrates for monitoring aquatic ecosystem condition and associated information gaps were recognized in the Adaptive Management Plan, Appendix E, of the Sierra Nevada Framework (USDA 2001, 2004), and one new research experiment exists (see sidebar on KREW above). McGurk and Fong (1995) found there was reduced diversity and increased dominance (most common taxa increase in fraction represented) in stream invertebrate communities in the Sierra Nevada when equivalent roaded area exceeded 5 percent (equivalent roaded area is an expression of landscape disturbance from roads and combined developed areas and logging).”

Aquatic Ecological Characteristics: Special Aquatic Habitats
Special aquatic habitats are areas of high biological diversity occupied by rare aquatic and terrestrial animal and plant species. These habitats attract a variety of terrestrial animals because they provide a concentrated food and water source. Special aquatic and riparian habitats may be sporadically distributed and uncommon compared to other habitat types like streams, rivers, and lakes. Typically, special habitats have specialized biotic communities with a high number of endemic species (Hynes 1970, Erman and Erman 1995, Erman 1996). Special habitats may represent environmental extremes with respect to water temperature, permanence, and chemistry, but they may also be stable environments, exhibiting little seasonal or annual variation. For example, cold water springs usually have a very constant year round discharge, temperature, and water chemistry. Other examples of specialized habitat types include hot springs, alkaline and caldera lakes (for example Mono Lake), fens, bogs, vernal pools, marshes, seeps, and snowmelt pools. Although special aquatic and riparian habitats contribute significantly to landscape and biological diversity, the biotic communities associated with special habitats are poorly known. Because special habitats are often small and isolated, they are sensitive to local impacts such as water diversions, mining, roads, and recreation. Even when special habitats connect to permanent water bodies, their local conditions and communities remain distinctive.
Cold spring habitats contribute significantly to biodiversity in areas where they occur. Erman and Erman (1990, 1995) surveyed 21 cold springs and their associated caddisfly fauna. They concluded that the biodiversity of cold spring fauna was highest in permanent springs with the highest discharge and calcium ion concentrations and the lowest solar radiation. Fauna of cold springs often represent rare, relict, and endemic species. Since cold springs are usually habitats that have been isolated for hundreds or thousands of years, they have quite distinctive fauna. Erman and Erman (1995) found that the average similarity between caddisfly species from separate springs was only 23 percent. A majority of caddisfly species (40 of 77) collected in the study area were present only in cold springs and spring-influenced streams.
Shepard (1993) noted that desert and eastern Sierra springs contain rich but poorly understood biodiversity. They are typically separated by distances of at least 12 miles, and dispersal between spring habitats is virtually impossible. Desert spring communities provide habitat for relictual species populations that became isolated as the climate become drier about 10,000 years ago. Although the fish species associated with springs are distinctive, invertebrates make up the great majority of the fauna. These invertebrates are microhabitat specialists. A particular species reaches its highest abundance where the combination of water depth, temperature, and velocity; substrate; and shade are most favorable. The most common aquatic invertebrates are insects, crustaceans, oligochaete worms, and mollusks. Spring snails in the family Hydrobiidae are often the most common macroinvertebrates present and they may reach densities of several thousand per square meter.
Fens are another poorly studied, sporadically occurring aquatic habitat in the Sierra Nevada. Erman and Erman (1975) studied several fens in the Sagehen Creek Basin and described general patterns there that may represent conditions elsewhere in the Region. Fens characteristically have flowing, mineral-rich water with high concentrations of calcium and magnesium ions, a pH ranging from near neutral to alkaline (pH 7.0 to 8.4), and shallow peat layers (less than 6.5 feet deep) . During the summer, fens undergo fluctuations in dissolved oxygen (from 35 to 95 percent saturation), temperature (from 9.5 to 30o centigrade), and water level. A few dozen moss and sedge species comprise the vegetation. Available oxygen is restricted closely to the water surface and fluctuates daily. The biotic community is limited to a few species. Most macroinvertebrates are oligochaete worms, nematodes, and aquatic flies. Water mites are often present at low abundances, and peaclams are rarely encountered.
Bogs are often confused with fens, but bogs receive nutrients from precipitation only. They also have a lower pH induced by sphagnum mosses as the mosses exchange hydrogen ions for mineral cations in the water. Moyle (1996) classified bogs as among the rarest of habitats in the Sierra Nevada/Modoc Plateau. Small, isolated bogs occur at high altitudes in the subalpine and headwaters zones of lakes and rivers in the southern Sierra (Barbour and Major 1990).
Spring Habitat Surveys
Broad-based surveys of special habitats have been conducted to a very limited degree over the Sierra Nevada region. One exception is the survey for springsnails of the family Hydrobiidae undertaken under terms of the 1998 Memorandum of Understanding Concerning the Conservation of Springsnails in the Great Basin, which was signed by five federal agencies, including the Forest Service, the Smithsonian Institution and The Nature Conservancy. Thousands of springs in the Great Basin were surveyed using the same protocol (Sada and Pohlmann 2002), many of which were located in the eastern foothills and mountains of the Sierra Nevada (Figure 1). Out of 127 sites surveyed under the Great Basin Springsnail MOU, Pyrgulopisis spp. occurred in 43, 11 of which were on National Forest lands. Tryonia occurred in 2 springs and Fluminicola at just one; none of these sites were on National Forest lands.

A second major survey effort was conducted under contract with Terry Frest and Ed Johannes of Deixis Consultants (2006, 2007). Surveys were directed at the northern Sierra Nevada national forests (i.e. Lassen Plumas, Tahoe, Eldorado and Lake Tahoe Basin Management Unit). A total of 222 sites, 201 of which were on national forest lands, were surveyed (Figure 1). Fluminicola spp. occurred at 41 sites, 35 of which are on national forest lands. Tryonia occurred at four sites, all of which are on national forest lands. Juga spp. (Family Pleuroceridae) occurred in 25 springs, 22 of which were on national forest lands. Snails in the family Pleuroceridae are often associated with springs.
In both the Great Basin and northern Sierra Nevada surveys, snails occurred in only about 25 percent of the springs surveyed. In the Great Basin surveys, Pyrgulopsis occurred at 34 percent (43/127) of sites surveyed and was the most commonly observed hydrobiid snail. Fluminicola was found at only one site. In contrast, Fluminicola was the most commonly observed hydrobiid in the northern Sierra Nevada surveys, where it occurred at 19 percent (41/222) of all sites surveyed. Pyrgulopsis was absent from the northern Sierra Nevada sites.
It is apparent from the figure below that extensive spring habitats of the Sierra Nevada Province remain unsurveyed. Several undescribed snail species were discovered during these spring habitat surveys and spring habitats contain both animal and plant species that may be confined to a single spring complex.
Locations of springs habitat surveys in the Sierra Nevada national forests for springsnails (Family Hydrobiidae) and Juga (Family Pleuroceridae). Vast areas of the Sierra Nevada Province spring habitats have not been systematically surveyed in spite of their importance to wildlife and the concentration of endemic and rare fauna that occur in such habitats.
Chap1_Aqua_AquaticMIS04.jpg
Aquatic Ecological Characteristics: Habitat Fragmentation

Habitat fragmentation is the loss of unity and cohesion and the splitting of habitat into isolated parts. Habitat fragmentation can result from physical, chemical or thermal barriers to species movements. The results of habitat fragmentation include isolation, loss of life history expression, reduced population genetic diversity, and increased vulnerability to disturbance and climate change.


Characteristics
Measure
Source
Dams
Length and distribution of habitat upstream of impassable dams
California Passage Assessment Database (PAD); SNDamFacilities_201024.gdb;
Cali_Dams.shp; National Hydrographic Dataset (NHD)
Diversions
Length and distribution of habitat upstream of impassable diversions
California Passage Assessment Database (PAD); SNDamFacilities_201024.gdb;
Cali_Dams.shp; National Hydrographic Dataset (NHD)
Diversions
Number and location of unscreened water diversions
State Water Resources Control Board database (EWRIM).
Dams & Diversions
Length and distribution of stream habitat with altered hydrograph and/or water temperature regimes downstream
NRIS AqS - Continuous H2O water temperature monitoring data; FERC relicensing data – H2O temperature and discharge data; USGS Gauge station data; California Data Exchange Center (CDEC), National Hydrographic Dataset (NHD)
Barriers at road-stream crossings
Length and distribution of habitat upstream of impassable road-stream crossing barriers
California Passage Assessment Database (PAD); NRIS AqS – Passage Characterization; WCATT -
A table of key characteristics for assessing aquatic habitat fragmentation. Various characteristics of habitat fragment types and measurements are displayed.


Fragmentation by Water Development
Water development has and is an important part of the economy and social development in California. The Sierra Nevada provides a large proportion of the water for agriculture in the central Valley, and food from California is an important supply for the country as well as internationally. California also has a very large population of people and they depend upon water sources on national forest lands, including the Sierra Nevada. These uses have resulted in a highly developed and modified water system in the Sierra Nevada. This has affected aquatic species, in particular fish and especially those that are anadromous and spend some of their life in the ocean, such as steelhead or salmon. Other fish that migrate or interbreed more locally, such as golden trout, may also be affected. Examples of fragmentation in wadeable streams are shown in the figures below for the southern portion of the bioregion.

Chap1_Aqua_AquaticMIS05.jpg
Fragmentation by Fire
Where populations have been constrained by habitat loss, fragmentation, and the expansion of exotic species, the probability for local extinctions linked to any disturbance has probably increased” (Rieman et al. 2003). If changes in fire patterns lead to larger, more severe disturbances than characteristic of at least the more recent evolutionary past for these species, the risks are compounded (i.e., fragmentation interacting with larger disturbances) (Dunham et al. 2003). Where these conditions coincide, the mitigation of extreme fires and their effects might benefit native fishes (Brown et al., 2001). However, higher severity fires can also benefit native fishes. In a study in Montana, native bull and cutthroat trout tended to increase with higher fire severity, particularly where debris flows occurred. (Sestrich et al. 2011). Similarly, in ponderosa pine and Douglas-fir forests of Idaho at 5-10 years post-fire, levels of aquatic insects emerging from streams were two and a half times greater in high-severity fire areas compared to unburned mature/old forest, and bats were nearly 5 times more abundant in riparian areas with high-severity fire than in unburned mature/old forest. (Malison and Baxter 2010).

“Limited evidence suggests vulnerability of fish to fire is contingent upon the quality of affected habitats, the amount and distribution of habitat (habitat fragmentation), and habitat specificity of the species in question. Species with narrow habitat requirements in highly degraded and fragmented systems are likely to be most vulnerable to fire and fire-related disturbance.” (Dunham et al. 2003)
“Effective pre-fire management activities will address factors that may render fish populations more vulnerable to the effects of fire (e.g., habitat degradation, fragmentation, and nonnative species)” (Dunham et al. 2003).“Proactive alternatives (pre-fire management) are most likely to have beneficial effects for fish, especially where habitat fragmentation and degradation have been identified as problems” (Dunham et al. 2003).

Fires can have substantial effects on streams and riparian systems and may threaten the persistence of some populations of fish, particularly those that are small and isolated (Rieman et al. 2003). Many fish populations are already depressed, small or isolated, and lack the resilience, diversity, or demographic support to rebound from disturbance (Rieman et al. 2003). According to Moyle and Williams (1990) and Moyle et al. (1996), many fish populations in the Sierra Nevada are restricted to small and often isolated remnants of a much larger and more continuous historical range. Moyle et al. (1996) determined that only 18 (45%) of the 40 fishes native to the Sierra Nevada have stable or expanding populations. Furthermore, Moyle and Randall (1996) evaluated the biological health of 100 Sierra-Nevada watersheds and found that less than half (43%) were in good to excellent condition. Regardless of the quality of local habitats, populations that are small and isolated are vulnerable” (Rieman et al. 2003).

“The potential impact of postfire changes on small, isolated populations can be devastating” (Spina & Tormey 2000).Remnant population networks and many of the remaining strongholds for native species are often found on public lands that now are key to the conservation of these species (Lee et al., 1997)” (Rieman et al. 2003).“Small and isolated populations do face greater risks of extinction (Dunham et al., 1999; Rieman and Dunham, 2000; Dunham et al. 2003).”“The influence of fire on persistence of native salmonid populations is highly variable. In some cases, local extinctions have been observed in response to fire, particularly in areas where populations of fishes have been isolated in small headwater streams” (Dunham et al. 2003).

Aquatic Ecological Characteristics: Watershed Condition

There have been two different watershed condition ratings for the Sierra Nevada. One is by the US Forest Service, using the Watershed Condition Framework. The second is in the CALFire Forest and Range Assessment Program (FRAP) report. Both are discussed here.


Forest Service Watershed Condition Framework
A total of 774 6th-field subwatersheds were assessed on the 10 Sierra Nevada National Forests in 2010 with the USFS Watershed Condition Framework, figure below. The subwatersheds ranged in size from 8,058 to 236,289 acres (including NFS and non-NFS lands), with a mean of 23,025 acres. The condition of different characteristics were rated by forest and district managers. There were multiple individual characteristics incorporated into the overall condition rating including: water quality, water quantity, habitat fragmentation, riparian habitat, in-stream logs, invasive species, native species, and other factors (need to make sure all are included).


Chap1_Aqua_AquaticMIS06.jpg
The first figure is the integrated index. Of these subwatersheds, 490 (63%) were classified as “functioning properly,” 280 (36%) were classified as “functioning at risk,” and 4 (0.5%) were classified as “impaired function.”



watconditionfrag.jpg
watconditionflow.jpg
watconditionwaterqual.jpg


California Forest And Range Assessment Program Report


The CALFire Forest and Range Assessment Program (FRAP) report evaluated watersheds for their value in providing water, based on surface water runoff, surface water storage, groundwater basins, and forest meadows. The Pit, North Fork Feather, East Branch North Fork Feather, Middle Fork Feather, North Fork and South Fork American, San Joaquin, and King River basins were rated as the watersheds with the highest water supply assets, all with composite scores of 100 of 100 possible points.

The FRAP report also evaluated threats to water supply within watersheds, based on impervious surfaces, future development, and climate change (snowpack change). The Truckee River was the only watershed in the Sierra Nevada that scored 100 of a possible 100 points for threats. The second highest composite threat score for a Sierra Nevada NFS watershed was 89.9 for the EB NF Feather River. Lake Tahoe was ranked third, with a composite score of 84.1. Threats to water quality were assessed, and of water bodies on NFS lands within Region 5 in the Sierra Nevada, only Lake Tahoe was listed as one of the “top” threatened watersheds.

Aquatic Ecosystem Literature Cited


Blinn, D.W. and D.B. Herbst. 2003. Use of diatoms and soft algae as indicators of stream abiotic determinants in the Lahontan Basin, USA. Final Report to the California Regional Water Quality Control Board, Lahontan Region and the California State Water Resources Control Board. Contract #01-119-160-0.
Blinn, D.W. and D.B. Herbst. 2007. Preliminary Index of Biological Integrity (IBI) for periphyton in the eastern Sierra Nevada, California – Unpublished, Draft Report.

EPA. 2006. Wadeable Streams Assessment: A Collaborative Survey of the Nation’s Streams, Office of Research and Development, Office of Water Washington, DC 20460; EPA 841-B-06-002. Available at http://www.epa.gov/owow/streamsurvey/
EPA. 2009. National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes. EPA 841-R-09-001. U.S. Environmental Protection Agency, Office of Water and Office of Research and Development, Washington, D.C.
EPA. 2011. 2012 National Lakes Assessment. Field Operations Manual. EPA 841-B-11-003. U.S. Environmental Protection Agency, Washington, DC. Available at http://www.cpcb.ku.edu/research/assets/2012_lakes/NLA%202012%20Field%20Operations%20Manual%202012.03.22.pdf
Fetscher, A.E., L. Busse, and P. R. Ode. 2009. Standard Operating Procedures for Collecting Stream Algae Samples and Associated Physical Habitat and Chemical Data for Ambient Bioassessments in California. California State Water Resources Control Board Surface Water Ambient Monitoring Program (SWAMP) Bioassessment SOP 002.
Hawkins, C.P., R.H. Norris, J.N. Hogue and J.W. Feminella. 2000. Development and evaluation of predictive models for measuring the biological integrity of streams. Ecological Applications 10:1456-1477.
Karr, J. R. 1991. Biological integrity: A long-neglected aspect of water resource management. Ecol. Appl. 1:66–84.
Karr, J. R., K. D. Fausch, P. L. Angermeier, P. R. Yant, and I. J. Schlosser. 1986. Assessing biological integrity in running waters: a method and its rationale. Ill. Nat. Hist. Surv. Spec. Publ. 5, Urbana, Ill. 28pp.
Moyle, P.B., 2002. Inland Fishes of California, Revised and Expanded. University of California Press, Berkeley. 502 pp.
Moyle, P.B., J.V.E. Katz, and R.M. Quiñones. 2011. Rapid decline of California’s native inland fishes: A status assessment. Biological Conservation 144:2414–2423.
Moyle, P. B., R. M. Yoshiyama, and R. A. Knapp. 1996. Status of fish and fisheries. Pages 953-973 In Sierra Nevada Ecosystem Project: Final report to Congress , Vol. II, assessments, commissioned reports, and background information. Davis: University of California, Centers for Water and Wildland Resources.
Ode. P.R., A.C. Rehn and J.T. May. 2005. A quantitative tool for assessing the integrity of southern coastal California streams. Environmental Management 35:493-504.

Ode, P.R., T.M. Kincaid, T. Fleming and A.C. Rehn. 2011. Ecological Condition Assessments of California’s Perennial Wadeable Streams: Highlights from the Surface Water Ambient Monitoring Program’s Perennial Streams Assessment (PSA) (2000-2007). A collaboration between the State Water Resources Control Board’s Non-Point Source Pollution Control Program (NPS Program), Surface Water Ambient Monitoring Program (SWAMP), California Department of Fish and Game Aquatic Bioassessment Laboratory, and the U.S. Environmental Protection Agency. Available at http://www.swrcb.ca.gov/water_issues/programs/swamp/docs/reports/psa_smmry_rpt.pdf .
Olsen, A.R. 2008a. USFS Region 5, Sierra Nevada National Forests, Stream Survey Design 2008. Environmental Protection Agency - National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR
Olsen, A.R. 2008b. USFS Region 5, Sierra Nevada National Forests, Lake Survey Design 2008. Environmental Protection Agency - National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR
Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, and R.M. Hughes. 1989. Rapid bioassessment protocols for use in streams and rivers: Benthic macroinvertebrates and fish. U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Washington, D.C. EPA 440-4-89-001.
Poff, N.L., Allan J.D., Bain M.B., Karr J.R., Prestegaard K.L., Richter B.D., Sparks R.E. & Stromberg J.C. 1997. The natural flow regime: a paradigm for river conservation and restoration. Bioscience, 47, 769–784.
Poff, N.L., M.M. Brinson and J.W. Day, Jr. 2002. Aquatic Ecosystems & Global Climate Change. Potential Impacts on Inland Freshwater and Coastal Wetland Ecosystems in the United States. Special Publication prepared for the Pew Center on Global Climate Change, Available at
http://www.w.pewtrusts.com/uploadedFiles/wwwpewtrustsorg/Reports/Protecting_ocean_life/env_climate_aquaticecosystems.pdf
Rehn, A.C. 2009. Benthic macroinvertebrates as indicators of biological condition below hydropower dams on west slope Sierra Nevada streams, California, USA. River Research and Applications 25:208-228.
Resh, V.H. 1979. Sampling variability and life history features: Basic consideration in the design of aquatic insect studies. Journal of the Fisheries Research Board of Canada 36:290-311.
Resh, V.H. and J.K. Jackson. 1993. Rapid assessment approaches to biomonitoring using benthic macroinvertebrates. Pages 195-233 in D.M. Rosenberg and V.H. Resh (editors). Freshwater biomonitoring and benthic macroinvertebrates. Chapman and Hall, New York.
Stevens, D. L., Jr., and A. R. Olsen. 2003. Variance estimation for spatially balanced samples of environmental resources. Environmetrics 14:593-610.
Stevens, D. L., Jr., and A. R. Olsen. 2004. Spatially-balanced sampling of natural resources in the presence of frame imperfections. Journal of American Statistical Association:99:262-278.

SWAMP (Surface Water Ambient Monitoring Program). 2006. Water Quality Assessment of the Condition of California Coastal Waters and Wadeable Streams. The Clean Water Act 305(b) Report to the Environmental Protection Agency. Available at http://www.swrcb.ca.gov/water_issues/programs/swamp/docs/factsheets/305breport2006.pdf


Aquatic Ecological Characteristics - Water Quantity

Baldwin, C. K., F. H Wagner and U. Lall. 2003. Water resources. Pages 79-112, in Wagner, F. H. (editor). Rocky Mountain/Great Basin Regional Climate-Change Assessment. Report of the U.S. Global Change Research Program. Utah State University, Logan, UT, USA. 240 pp.
Barnett, T. P., D. W. Pierce, H. G. Hidalgo, C. Bonfils, B. D. Santer, T. Das, G. Bala, A. W. Wood, T. Nozawa, A. A. Mirin, D. R. Cayan, and M. D. Dettinger. 2008. Human-induced changes in the hydrology of the western United States. Science 319:1080-1083.
Christy, J.R. and J. J. Hnilo. 2010. Changes in snowfall in the southern Sierra Nevada of California since 1916. Energy and the Environment 21: 223-234.
DeGraff, J., D. Wagner, A. Gallegos, M. DeRose, C. Shannon, and T. Ellsworth, 2011. The remarkable occurrence of large rainfall-induced debris flows at two different locations on July 12, 2008, Southern Sierra Nevada, CA, USA. Landslides 8:343-353.
Hamlet, A. F., P. W. Mote, M. P. Clark, and D. P. Lettenmaier. 2007. Twentieth-century trends in runoff, evapotranspiration, and soil moisture in the western United States. Journal of Climate 20:1468-1486.
Huggel, C., J.J. Clague, and O. Korup. 2012. Is climate change responsible for changing landslide activity in high mountains? Earth Surface Processes and Landforms 37: 77-91.
Kaushal, S. S., G. E. Likens, N. A. Jaworski, M. L. Pace, A. M. Sides, D. Seekell, K. T. Belt, D. H. Secor, and R. L. Wingate. 2010. Rising stream and river temperatures in the United States. Frontiers in Ecology and the Environment 8:461-466.
Kim, J. 2005. A projection of the effects of the climate change induced by increased CO2 on extreme hydrologic events in the western US. Climatic Change 68:153-168.
Maurer, E. P., I. T. Stewart, C. Bonfils, P. B. Duffy, and D. Cayan. 2007. Detection, attribution, and sensitivity of trends toward earlier streamflow in the Sierra Nevada. Journal of Geophysical Research-Atmospheres 112.
McCabe, G. J., M. P. Clark, and L. E. Hay. 2007. Rain-on-snow events in the western United States. Bulletin of the American Meteorological Society 88:319-+.
Miller, N. L., K. E. Bashford and E. Strem. 2003. Potential impacts of climate change on California hydrology. Journal of the American Water Resources Association 39: 771- 784.
Moser, S., G. Franco, S. Pittiglio, W. Chou, D. Cayan. 2009. The future is now: An update on climate change science impacts and response options for California. California Climate Change Center Report CEC-500-2008-071, May 2009. California Energy Commission, Sacramento, CA.
Mote, P. W., A. F. Hamlet, M. P. Clark, and D. P. Lettenmaier. 2005. Declining mountain snowpack in western north America. Bulletin of the American Meteorological Society 86:39-+.
Null, S. E., J. H. Viers, and J. F. Mount. 2010. Hydrologic Response and Watershed Sensitivity to Climate Warming in California's Sierra Nevada. Plos One 5.
Pagano, T. and D. Garen. 2005. A recent increase in western US streamflow variability and persistence. Journal of Hydrometeorology 6:173-179.
Reba, M. L., D. Marks, A. Winstral, T. E. Link, and M. Kumar. 2011. Sensitivity of the snowcover energetics in a mountain basin to variations in climate. Hydrological Processes 25:3312-3321.
Regonda, S. K., B. Rajagopalan, M. Clark, and J. Pitlick. 2005. Seasonal cycle shifts in hydroclimatology over the western United States. Journal of Climate 18:372-384.
Stewart, I.T., D. R. Cayan, and M. D. Dettinger. 2005. Changes toward earlier streamflow timing across western North America. Journal of Climate 18: 1136-1155.
Young, C. A., M. I. Escobar-Arias, M. Fernandes, B. Joyce, M. Kiparsky, J. F. Mount, V. K. Mehta, D. Purkey, J. H. Viers, and D. Yates. 2009. Modeling the Hydrology of Climate Change in California's Sierra Nevada for Subwatershed Scale Adaptation1. Journal of the American Water Resources Association 45:1409-1423.

Amphibian Characteristics Literature Cited

AmphibiaWeb. Information on amphibian biology and conservation. [web application]. 2009. Berkeley, California: AmphibiaWeb. Available: http://amphibiaweb.org/. (Accessed: Feb 15, 2013).
Knapp, R.A.; Briggs, C.J.; Smith, T.C.; Maurer, J.R. 2011. Nowhere to hide: impact of a temperature-sensitive amphibian pathogen along an elevation gradient in the temperate zone. Ecosphere. 2:1–26.
Pope, K. and J. Long. 2013. Lakes: recent research and restoration strategies. Pages xxx-xxxin: Long, Jonathan; Skinner, Carl; North, Malcolm; Winter, Pat; Zielinski, Bill; Hunsaker, Carolyn; Collins, Brandon; Keane, John; Lake, Frank; Wright, Jessica; Moghaddas, Emily; Jardine, Angela; Hubbert, Ken; Pope, Karen; Bytnerowicz, Andrzej; Fenn, Mark; Busse, Matt; Charnley, Susan; Patterson, Trista; Quinn-Davidson, Lenya; Safford, Hugh; chapter authors and Synthesis team members. Bottoms, Rick; Hayes, Jane; team coordination and review. Meyer, Marc; Herbst, David; Matthews, Kathleen; additional contributors. USDA Forest Service Pacific Southwest Research Station. 2013. Science Synthesis to support Forest Plan Revision in the Sierra Nevada and Southern Cascades. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 504 p.
Sodhi N.S., Bickford D., Diesmos A.C., Lee T.M., Koh L.P., et al. 2008 Measuring the Meltdown: Drivers of Global Amphibian Extinction and Decline. PLoS ONE 3(2): e1636. doi:10.1371/journal.pone.0001636

Water Temperature Characteristics Literature Cited

Armour, C.L. 1991. Guidance for evaluating and recommending temperature regimes to protect fish. Instream Flow Information Paper 27. Biological Report 90(22). U.S. Fish and Wildlife Service, National Ecology Research Center, Fort Collins, CO.
Broadmeadow, S. B., J. G. Jones, T. E. L. Langford, P. J. Shaw, and T. R. Nisbet. 2011. The influence of riparian shade on lowland stream water temperatures in southern England and their viability for brown trout. River Res. Applic., 27: 226–237.
California Department of Fish and Game. 2010. Effects of water temperature on anadromous salmonids in the San Joaquin River Basin, DFG Exhibit 4, prepared for the informational proceeding to develop flow criteria for the delta ecosystem necessary to protect public trust resources before the State Water Resources Control Board. Retrieved February 7, 2013 from http://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=17962
Caissie, D. 2006. The thermal regime of rivers—A review: Freshwater Biology, v. 51, p. 1389-1406.
Coutant ,C.C. 1977. Compilation of temperature preference data. Journal of the Fisheries Research Board of Canada, 34, 739–745.
Coutant, C.C. 1999. Perspective on Temperature in the Pacific Northwest’s Fresh Water. Environmental Sciences Division, Publication No. 4849, Oak Ridge National Laboratory, ORNL/TM-1999/44. Oak Ridge National Laboratory, Oak Ridge, Tennessee, 109 p.
Dunham, J.B., M. M. Peacock, B.E. Rieman, R.E. Schroeter, and G.L. Vinyard. 1999. Local and geographic variability in the distribution of stream-living Lahontan cutthroat trout. Transactions of the American Fisheries Society 128:875-889.
Dunhan, J., B. Rieman, and G. Chandler. 2001. Development of field-based models of suitable thermal regimes for interior Columbia Basin salmonids. Boise, ID: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. Final Report RMRS-00-IA-11222014-521. 79 p.
Eaton, J.G., J. H. McCormick, B. E. Goodno, D. G. O'Brien, H. G. Stefany, M. Hondzo & R. M. Scheller. 1995. A field information-based system for estimating fish temperature tolerances. Fisheries 20(4):10-18.
Ebersole, J.L., W.J. Liss, and C.A. Frissell. 2001. Relationship between stream temperature, thermal refugia, and rainbow trout Oncorhynchus mykiss abundance in arid-land streams of the northwestern United States. Ecology of Freshwater Fish 10:1-10.
Elliott, J.M. 1981. Some aspects of thermal stress on freshwater teleosts. Pages 209-245 in A. D. Pickering, editor. Stress and Fish. Academic Press, London.
Fausch, K.D., S. Nakano and K. Ishigaki. 1994. Distribution of two congeneric charrs in streams of Hokkaido Island, Japan: considering multiple factors across scales. Oecologia 100:1-12.
Flebbe, P.A. 1994. A regional view of the margin: salmonid abundance and distribution in the southern Appalachian mountains of North Carolina and Virginia. Transactions of the American Fisheries Society 123:657-667.
Fry, F. E. J. 1967. Responses of poikilotherms to temperature. Pages 375-709 in A. H. Rose, ed. Thermobiology. Academic Press, San Diego, Calif. 653 pp.
Fry, F. E. J. 1971. The effect of environmental factors on the physiology of fish. Pages l-98 in W. S. Hoar and D. J. Randall, eds. Fish physiology. Vol. VI. Environmental relations and behavior. Academic Press, San Diego, Calif. 559 pp.
Hawkins C.P., J.N. Nogue, L.M. Decker and J.W. Feminella. 1997. Channel morphology, water temperature, and assemblage structure of stream insects. Journal of the North American Benthological Society, 16, 728–749.
Hutchinson, V. H. 1976. Factors influencing thermal tolerances of individual organisms. Pages 10-16 in Proceedings of the Second Sauana River Ecology Laboratory Conference, April 1975, Augusta, Georgia. Available from NTIS, CONF.- 750425.
Hynes, H.B.N. 1960. The Biology of Polluted Waters. Liverpool University Press, Liverpool, 202 p.
Johnson, S.L. 2004. Factors influencing stream temperatures in small streams: substrate effects and a shading experiment. Canadian Journal of Fish and Aquatic Sciences. 61: 913–923.
Lowney, C.L. 2000. Stream temperature variation in regulated rivers: evidence for a spatial pattern in daily minimum and maximum magnitudes. Water Resources Research, 36, 2947–2955.
Magnuson, J.J., L.B. Crowder, and P.A. Medvick. 1979. Temperature as an ecological resource. American Zoologist 19:331-343.
Nakano, S., F. Kitano, and K. Maekawa. 1996. Potential fragmentation and loss of thermal habitats for charrs in the Japanese archipelago due to climatic warming. Freshwater Biology 36:711-722.
Nielsen, J.L., T.E. Lisle, and V. Ozaki. 1994. Thermally stratified pools and their use by steelhead in northern California streams. Transactions of the American Fisheries Society 123:613-626.
Peterson, J.T., and C.F. Rabeni. 1996. Natural thermal refugia for temperate warmwater stream fishes. North American Journal of Fisheries Management 16: 738-746.
Poole, G.C. and C.H. Berman. 2001. An ecological perspective on instream temperature: natural heat dynamics and mechanisms of human-caused thermal degradation. Environ. Manag. 27: 787–802.
Poole, G., J. Risley, and M. Hicks. 2001. Spatial and Temporal Patterns of Stream Temperature (Revised). Issue Paper 3 Prepared as Part of EPA Region 10 Temperature Water Quality Criteria Guidance Development Project. EPA-910-D-01-003.
Rieman, B.E., D.C. Lee, and R.F. Thurow. 1997. Distribution, status, and likely future trends of bull trout within the Columbia River and Klamath Basins. North American Journal of Fisheries Management 17:1111-1125.
Sinokrot, B.A. and J.S. Gulliver. 2000. In-stream flow impact on river water temperatures. Journal of Hydraulic Research, 38, 339–349.
Stanford, J. A., and F. R. Hauer. 1992. Mitigating the impacts of stream and lake regulation in the Flathead River catchment, Montana, USA: An ecosystem perspective. Aquatic Conservation: Marine and Freshwater Ecosystems 2:35– 63.
Stoneman, C.L. and L.J. Michael. 1996. A simple method to classify stream thermal stability with single oberservations of daily maximum water and air temperature. North Am J Fish Manage 16:728-737.
Thomas, L. 2005. Keeping it cool: unraveling the influences on stream temperature. Pacific Northwest Research Station Science Findings, Issue 73.
Troxler, R.W. and E.L. Thackston. 1977. Predicting the rate of warming of rivers below hydro-electric installations. Journal of the Water Pollution Control Federation, August, 1902–1912.
Vannote R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell and C.E. Cushing. 1980. The river continuum concept. Canadian Journal of Fisheries and Aquatic Sciences, 37, 130–137.
Ward, J. V., and J. A. Stanford. 1995. Ecological connectivity in alluvial river ecosystems and its disruption by flow regulation. Regulated Rivers: Research and Management 11:105–119.
Webb, B.W. and D.E. Walling. 1993. Temporal variability in the impact of river regulation on thermal regime and some biological implications. Freshwater Biology, 29, 167–182.
Webb, B.W. and D.E. Walling. 1996. Long-term variability in the thermal impact of river impoundment and regulation. Applied Geography, 16, 211–227.
Webb, B.W. and Y. Zhang. 1997. Spatial and seasonal variability in the components of the river heat budget. Hydrol Proc 11:79-101.

Macroinvertebrate and Algae Characteristics Literature Cited

Blinn, D.W. and D.B. Herbst. 2003. Use of diatoms and soft algae as indicators of stream abiotic determinants in the Lahontan Basin, USA. Final Report to the California Regional Water Quality Control Board, Lahontan Region and the California State Water Resources Control Board. Contract #01-119-160-0.
Blinn, D.W. and D.B. Herbst. 2007. Preliminary Index of Biological Integrity (IBI) for periphyton in the eastern Sierra Nevada, California – Unpublished, Draft Report.
EPA. 2006. Wadeable Streams Assessment: A Collaborative Survey of the Nation’s Streams, Office of Research and Development, Office of Water Washington, DC 20460; EPA 841-B-06-002. Available at __http://www.epa.gov/owow/streamsurvey/__

EPA. 2009. National Lakes Assessment: A Collaborative Survey of the Nation’s Lakes. EPA 841-R-09-001. U.S. Environmental Protection Agency, Office of Water and Office of Research and Development, Washington, D.C.

EPA. 2011. 2012 National Lakes Assessment. Field Operations Manual. EPA 841-B-11-003. U.S. Environmental Protection Agency, Washington, DC. Available at http://www.cpcb.ku.edu/research/assets/2012_lakes/NLA%202012%20Field%20Operations%20Manual%202012.03.22.pdf

Fetscher, A.E., L. Busse, and P. R. Ode. 2009. Standard Operating Procedures for Collecting Stream Algae Samples and Associated Physical Habitat and Chemical Data for Ambient Bioassessments in California. California State Water Resources Control Board Surface Water Ambient Monitoring Program (SWAMP) Bioassessment SOP 002.

Hawkins, C.P., R.H. Norris, J.N. Hogue and J.W. Feminella. 2000. Development and evaluation of predictive models for measuring the biological integrity of streams. Ecological Applications 10:1456-1477.

Karr, J. R. 1991. Biological integrity: A long-neglected aspect of water resource management. Ecol. Appl. 1:66–84.

Karr, J. R., K. D. Fausch, P. L. Angermeier, P. R. Yant, and I. J. Schlosser. 1986. Assessing biological integrity in running waters: a method and its rationale. Ill. Nat. Hist. Surv. Spec. Publ. 5, Urbana, Ill. 28pp.

Moyle, P.B., 2002. Inland Fishes of California, Revised and Expanded. University of California Press, Berkeley. 502 pp.

Moyle, P.B., J.V.E. Katz, and R.M. Quiñones. 2011. Rapid decline of California’s native inland fishes: A status assessment. Biological Conservation 144:2414–2423.

Ode, P.R., T.M. Kincaid, T. Fleming and A.C. Rehn. 2011. Ecological Condition Assessments of California’s Perennial Wadeable Streams: Highlights from the Surface Water Ambient Monitoring Program’s Perennial Streams Assessment (PSA) (2000-2007). A collaboration between the State Water

Resources Control Board’s Non-Point Source Pollution Control Program (NPS Program), Surface Water Ambient Monitoring Program (SWAMP), California Department of Fish and Game Aquatic Bioassessment Laboratory, and the U.S. Environmental Protection Agency. Available at http://www.swrcb.ca.gov/water_issues/programs/swamp/docs/reports/psa_smmry_rpt.pdf.

Ode. P.R., A.C. Rehn and J.T. May. 2005. A quantitative tool for assessing the integrity of southern coastal California streams. Environmental Management 35:493-504.

Ode, P.R. and K. Schiff. 2009. Recommendations for the development and maintenance of a reference condition management program (RCMP) to support biological assessment of California’s wadeable streams. Report to the State Water Resources Control Board’s Surface Water Ambient Monitoring

Program (SWAMP), Sacramento, CA. Available at http://www.waterboards.ca.gov/water_issues/programs/swamp/docs/qamp/wadestreams_rcmpfinal.pdf

Olsen, A.R. 2008a. USFS Region 5, Sierra Nevada National Forests, Stream Survey Design 2008. Environmental Protection Agency - National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR

Olsen, A.R. 2008b. USFS Region 5, Sierra Nevada National Forests, Lake Survey Design 2008. Environmental Protection Agency - National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, OR

Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, and R.M. Hughes. 1989. Rapid bioassessment protocols for use in streams and rivers: Benthic macroinvertebrates and fish. U.S. Environmental Protection Agency, Office of Water Regulations and Standards, Washington, D.C. EPA 440-4-89-001.

Poff, N.L., Allan J.D., Bain M.B., Karr J.R., Prestegaard K.L., Richter B.D., Sparks R.E. & Stromberg J.C. 1997. The natural flow regime: a paradigm for river conservation and restoration. Bioscience, 47, 769–784.

Poff, N.L., M.M. Brinson and J.W. Day, Jr. 2002. Aquatic Ecosystems & Global Climate Change. Potential Impacts on Inland Freshwater and Coastal Wetland Ecosystems in the United States. Special Publication prepared for the Pew Center on Global Climate Change, Available at
__http://www.w.pewtrusts.com/uploadedFiles/wwwpewtrustsorg/Reports/Protecting_ocean_life/env_climate_aquaticecosystems.pdf__

Rehn, A.C. 2009. Benthic macroinvertebrates as indicators of biological condition below hydropower dams on west slope Sierra Nevada streams, California, USA. River Research and Applications 25:208-228.

Resh, V.H. 1979. Sampling variability and life history features: Basic consideration in the design of aquatic insect studies. Journal of the Fisheries Research Board of Canada 36:290-311.

Resh, V.H. and J.K. Jackson. 1993. Rapid assessment approaches to biomonitoring using benthic macroinvertebrates. Pages 195-233 in D.M. Rosenberg and V.H. Resh (editors). Freshwater biomonitoring and benthic macroinvertebrates. Chapman and Hall, New York.

Stevens, D. L., Jr., and A. R. Olsen. 2003. Variance estimation for spatially balanced samples of environmental resources. Environmetrics 14:593-610.

Stevens, D. L., Jr., and A. R. Olsen. 2004. Spatially-balanced sampling of natural resources in the presence of frame imperfections. Journal of American Statistical Association:99:262-278.

SWAMP (Surface Water Ambient Monitoring Program). 2006. Water Quality Assessment of the Condition of California Coastal Waters and Wadeable Streams. The Clean Water Act 305(b) Report to the Environmental Protection Agency. Available at http://www.swrcb.ca.gov/water_issues/programs/swamp/docs/factsheets/305breport2006.pdf

Special Aquatic Habitat Literature Cited

Barbour, Michael G. and Jack Major (eds.). 1990. Terrestrial Vegetation of California. California Native Plant Society (CNPS) Special Publication No. 9. Sacramento, CA 95814.

Erman, D.C. and N.A. Erman. 1975. Macroinvertebrate composition and production in some Sierra Nevada Minerotrophic peatlands. Ecology 56:591-603.

Erman, N.A. 1996. Status of aquatic invertebrates. Pages 987-1008 In Sierra Nevada Ecosystem Project: Final Report to Congress, Assessments and scientific basis for management options. Vol II, chp 35. University of California, Centers for Water and Wildland Resources, Davis, CA 95616-8750.

Erman, N.A. and D.C. Erman. 1990. Biogeography of caddisfly (Trichoptera) assemblages in cold springs of the Sierra Nevada (California, USA). Contribution 200. University of California, California Water Resources Center, Davis, CA 95616. 28 pages.

Erman, N.A. and D.C. Erman. 1995. Spring permanence, Trichoptera species richness, and the role of drought. Biodiversity of Aquatic Insects and Other Invertebrates. Journal of the Kansas Entomological Society 68(2):50-64 supplement.

Frest, T.J. and E.J. Johannes. 2006. Progress Report Freshwater Mollusk Survey of northern Sierra Nevada National Forests, 2006. USDA Forest Service, PSW Regional Office, Vallejo, CA. 10 pp.

Frest, T.J. and E.J. Johannes. 2007. Progress Report on 2006 Freshwater Mollusk Fieldwork in Sierra Nevada National Forests, California. USDA Forest Service, PSW Regional Office, Vallejo, CA. 20 pp.

Hynes, H.B.N. 1970. The Ecology of Running Waters. Liverpool University Press, Liverpool, England. 555 pages.

Moyle, P.B. 1996. Status of aquatic habitat types. Pages 945-952 In Sierra Nevada Ecosystem Project, Final Report to Congress, Vol. II, Assessments and scientific basis for management options. University of California, Centers for Water and Wildland Resources, Davis. CA. 95616.

Sada, D.W. and K.F. Pohlmann. 2002. Spring Inventory and Monitoring Protocols. Conference Proceedings. Spring-fed Wetlands: Important Scientific and Cultural Resources of the Intermountain Region. Available at __http://www.wetlands.dri.edu__ .

Shepard, W.D. 1993. Desert springs- both rare and endangered. Aquatic Conservation: Marine and Freshwater Ecosystems 3:351-359.


Habitat Fragmentation Literature Cited

Brown, K. D., A. A. Echelle, D. L. Propst, J. E. Brooks, andW. L. Fisher. 2001. Catastrophic wildfire and number of populations as factors influencing risk of extinction for gila trout. Western North American Naturalist 61:139–148.

Dunham, J. B., A. E. Rosenberger, C. H. Luce, and B. E. Rieman. 2007. Influences of wildfire and channel reorganization on spatial and temporal variation in stream temperature and the distribution of fish and amphibians. Ecosystems 10:335–346.

Malison, R.L., and C.V. Baxter. 2010. The fire pulse: wildfire stimulates flux of aquatic prey to terrestrial habitats driving increases in riparian consumers. Canadian Journal of Fisheries and Aquatic Sciences 67: 570-579.

Moyle, P.B., Williams, J.E., 1990. Biodiversity loss in the temperate zone: decline of the native fish fauna of California. Conserv. Biol. 4(3), 275-284.

Moyle, P.B., Yoshiyama, R.M., Knapp, R.A., 1996. Status of fish and fisheries. Sierra Nevada Ecosystem Project: Final Report to Congress. Volume II. Centers for Water and Wildland Resources, University of California, Davis, pp. 953-973.

Moyle, P.B. and P.J. Randall. 1996. Biotic Integrity of Watersheds. Sierra Nevada Ecosystem Project: Final Report to Congress. Volume II. Centers for Water and Wildland Resources, University of California, Davis, pp. 975-983.

Rieman, B. E., D. Lee, G. Chandler, and D. Myers. 1997. Does wildfire threaten extinction for salmonids: responses of redband trout and bull trout following recent large fires on the Boise National Forest. Pages 47–57 in J. Greenlee, editor. Proceedings of the symposium on fire effects on threatened and endangered species and habitats. International Association of Wildland Fire, Fairfield, Washington.

Rieman, B.E., Dunham, J.B., 2000. Metapopulation and salmonids: a synthesis of life history patterns and empirical observations. Ecol. Freshw. Fish 9, 51-64.

Rieman, B. E., D. Lee, D. Burns, R. Gresswell, M. K. Young, R. Stowell, J. Rinne, and P. Howell. 2003. Status of native fishes in the western United States and issues for fire and fuels management. Forest Ecology and Management 178:197–211.


Sestrich, C.M., T.E. McMahon, and M.K. Young. 2011. Influence of fire on native and nonnative salmonid populations and habitat in a western Montana basin. Transactions of the American Fisheries Society 140: 136-146.

Spina, A.P., and Tormey, D.R., 2000. Postfire sediment deposition in geographically restricted steelhead habitat. N. Amer J. Fish. Manage. 20:562–569.

TACCIMO Climate Change Tool Literature http://goo.gl/Lg3Bn

TACCIMO – Fish Information
Jager, H. I., van Winkle, W., & Holcomb, B. D. 1999. Would hydrologic climate changes in Sierra Nevada streams influence trout persistence? Transactions of the American Fisheries Society, 128, 222-240.
Katz, J., Moyle, P. B., Quinones, R. M., Israel, J. & Purdy, S. 2012. Impending extinction of salmon, steelhead, and trout (Salmonidae) in California. Environmental Biology of Fishes, DOI 10.1007/s10641-012-9974-8
Kiernan, J. D. & Moyle, P. B. 2012. Flows, droughts, and aliens: factors affecting the fish assemblage in a Sierra Nevada, California, stream. Ecological Applications, 22 (4),1146 – 1161.
Marchetti, M. P. & Moyle, P. B. 2001. Effects of flow regime on fish assemblages in a regulated California stream. Ecological Applications, 11 (2), 530-539.
Meyers, E. M., Dobrowski, B., Tague, C. L. 2010. Climate Change Impacts on Flood Frequency, Intensity, and Timing May Affect Trout Species in Sagehen Creek, California. Transactions of the American Fisheries Society, 139 (6), 1657-1664.
Moyle, P. B., Kiernan, J. D., Crain, P. K. & Quicones, R. M. 2012. Projected effects of future climates on freshwater fishes of California. California Energy Commission. Publication number: CEC-500-2012-028.
Null, S. E., Viers, J. H., Deas, M. L., Tanaka, S. K. & Mount, J. F. 2012. Stream temperature sensitivity to climate warming in California’s Sierra Nevada: impacts to coldwater habitat. Climatic Change, DOI 10.1007/s10584-012-0459-8
Rahel, F. J., Bierwagen, B., & Taniguchi, Y. 2008. Managing aquatic species of conservation concern in the face of climate change and invasive species. Conservation Biology, 22(3), 551-561.

TACCIMO – Amphibians Information
Blaustein, A. R., Walls, S. C., Bancroft, B. A., Lawler, J. J., Searle, C. L., & Gervasi, S. S. 2010. Direct and indirect effects of climate change on amphibian populations. Diversity, 2(2), 281-313. doi:10.3390/d2020281
Davidson, C., Shaffer, H. B. & Jennings, M. R. 2001. Declines of the California red-legged frog: Climate, UV-B, habitat, and pesticides hypotheses. Ecological Applications, 11(2), 464 – 479.
Davidson, C., Shaffer, H. B. & Jennings, M. R. 2002. Spatial tests of the pesticide drift, habitat destruction, UV-B, and climate-change hypotheses for California amphibian declines. Conservation Biology, 16(6), 1588 – 1601.
Lacan, I., Matthews, K. & Feldman, K. 2008 Interaction of an introduced predator with future effects of climate change in the recruitment dynamics of the imperiled Sierra Nevada yellow-legged frog (Rana sierra). Herpetological Conservation and Biology, 3 (2), 211 – 223.
Wake, D. B. & Vredenburg. 2008. Are we in the midst of the sixth mass extinction? A view from the world of amphibians. Proceedings of the National Academy of Science, 105 (Suppl 1), 11466-11473.

TACCIMO – Invertebrate Information
Herbst, D. B. & Cooper, S. D. 2010. Before and after the deluge: rain-on-snow flooding effects on aquatic invertebrate communities of small streams in the Sierra Nevada, California. Journal of the North American Benthological Society, 29(4), 1354 – 1366. DOI: 10.1899/09-185.1

Additional References added from SFL's Conservation Strategy

Derlet, R. W., Goldman, C. and Conner, M. J. 2010. Reducing the impact of summer cattle grazing on water quality in the Sierra NevadaMountains of California: a proposal. Journal of Water and Health 8(2):326-333.
Furniss, M., Roelofs, J. T. D. and Yee, C. S. 1991. Road Construction and Maintenance. In: Influences of Forest and Rangeland Management. Meehan, W. R. ed. Bethesda, Maryland: American Fisheries Society Special Publication 19. pp. 297-324.
Frissell, C.A., Scurlock, M. and Kattelman, R. 2012. SNEP Plus 15 Years: Ecological & Conservation Science for Freshwater ResourceProtection & FederalLand Management in the Sierra Nevada. Summary report for a scientific workshop held at Davis, California, 12-13 December 2011. Pacific Rivers Council Science Publication 12-001. 39 pp.
Gucinski, H., Furniss, M. J., Ziemer, R. R. and Brookes, M. H. 2001. Forest Roads: A Synthesis of Scientific Information. Gen. Tech. Rep. PNWGTR-509. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, OR.
Scurlock, M. and Frissell, C. 2012. Conservation of Freshwater Ecosystems on Sierra Nevada National Forests: Policy Analysis and Recommendations for the Future. Pacific Rivers Council. June, 2012.
Siegel, R. B. and DeSante, D. F. 1999. Draft avian conservation plan for the Sierra Nevada Bioregion: conservation priorities and strategies for safeguarding Sierra bird populations. Institute for Bird Populations report to California Partners in Flight. Version 1.0.
Thompson, L.C., Escobar, M.I., Mosser, C.M., Purkey, D.R., Yates, D., Moyle, P.B. 2011. Water management adaptations to prevent loss of spring-run Chinook salmon in California under climate change. J. Water Resour. Plann. Manage., 10.1061/(ASCE)WR.1943-5452.0000194.
USDA Forest Service and USDI Fish and Wildlife Service 1995. PACFISH - Implementation of Interim Strategies for Managing Anadromous Fish-Producing Watersheds in Eastern Oregon and Washington, Idaho, and portions of California. February 24, 1995.
USDA Forest Service Watershed Condition Advisory Team 2011. Watershed Condition Framework: A Framework for Assessing and Tracking Changes to Watershed Condition, FS-977. http://www.fs.fed.us/publications/watershed/Watershed_Condition_Framework.pdf
United States Environmental Protection Agency (USEPA) 2008. Comments on Western Oregon Plan Revisions. January 9, 2008.
Williamson, C. E., Dodds, W., Kratz, T. K., and Palmer, M. A. 2008. Lakes and streams as sentinels of environmental change in terrestrial and atmospheric processes. Front. Ecol. Environ. 6:247–254.
Williamson, C. E., Saros, J. E., and Schindler, D. W. 2009. Sentinels of change. Science 323:887–889.

[snapshot: 4/9/2013 @0934]



Bio-Region Terrestrial Ecosystems

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF

Table of Contents

Sierra Nevada Bio-region
Chapter 1: Ecological Integrity of Ecosystems - Terrestrial Ecosystems

Current Condition

Introduction

A rich diversity of ecosystems are found in the Sierra Nevada bio-region because of the diverse climate and topography, as well as juxtaposition of several regional floras (Minich 2007). To the north, it is influenced by the Great Basin, Cascade Range and Klamath Mountains. To the west, the Great Valley of California, and to the east the Great Basin and Mojave Desert intergrade with the bio-regional analysis area. To the south are the mountain ranges of southern California. Within the Sierra Nevada, there is great diversity of elevations and precipitation patterns, as well as geology. About 50% of California’s 7,000 plant species occur in the Sierra Nevada (Shevock 1996). Four hundred of these species occur only in the Sierra Nevada, they are endemic. Similarly, 60% of the state’s animals (including mammals, birds, reptiles, and amphibians) occur in the bio-region (Graber 1996).

Characterizing ecosystems is like painting a landscape. Each different artist may paint the landscape differently, using different color schemes and levels of detail, but it is still the same landscape. Similarly, the terrestrial ecosystems of the bio-region can be looked at with a “broad brush” or with fine detail. In this assessment, for the most part, the broad brush approach or “coarse-filter” approach is appropriate, since the area is so large and ecosystems so diverse. In some instances, certain ecosystems warrant more detailed attention because of their rarity and significance to ecosystem function or human values. These include, but should not be limited to, aspen communities and giant sequoia forests.

Using a coarse-filter approach, the vegetation types or habitat types, are a useful way to describe the current condition and trends, and integrity of ecosystems. This means that instead of trying to catalog and assess the condition of all of the individual species and locations, the forests or chaparral they live in is assessed. Another important coarse filter approach is to examine key changes that affect vegetation or habitat types. In the Sierra Nevada, fire is potent force that can change vegetation or habitat types. There are some elements of habitat that are critical to numerous species and occur throughout different vegetation types.

However, in PSW-GTR-237, Managing Sierra Nevada Forests (2012) authors Malcolm North and Patricia Manley suggest that “coarse filter” approaches such as the California Wildlife-Habitat Relations model “generally fail to account for the different spatial and temporal scales at which species may respond to forest conditions or assess habitat features other than large trees and canopy cover.”

The issue of simplification of forest ecosystems is at the heart of the issue of loss of biodiversity: they are two sides of the same coin. It can be summed up this way, quoting from the 1996 Sierra Nevada Ecosystem Project: "The primary impact of 150 years of forestry on middle-elevation conifer forests has been to simplify structure (including large trees, snags, woody debris of large diameter, canopies of multiple heights and closures, and complex spatial mosaics of vegetation), and presumably function, of these forests" (SNEP 1996, Summary, p. 6).

Legacy structures and species disappear as forests become more homogenized or simplified. These include snags, or standing dead trees, down wood, and old-growth trees with complex features like cavities, chambers, and mistletoe brooms. Many of these structures are unique and may take many decades to develop; other biological features associated with old forest include mycorrhizal symbionts and old-growth associated fungi, lichens, and terrestrial orchids. Together with the many important elements of the early forest types, and diverse geomorphic and other abiotic features, unique niches are formed that give rise to the rich biological diversity that characterizes the Sierra Nevada region.

Other features that comprise the forest diversity landscape that are not captured in a broad brush, or coarse filter approach, are rock outcrops, small meadows, seeps and springs; unique hardwood stands, and certain types of chaparral.

Salvage logging is particularly detrimental to forest biodiversity, erasing not only the post-fire structure but also skipping the "forgotten stage of forest succession" (Swanson et al 2010). Forest types that are allowed to naturally regenerate after fire without interference (eg salvage logging/planting/herbicides) are now among the rarest type of forest ecosystem in western forests (see for example, comments in attached PDF, J. Franklin, Biscuit Fire DEIS, 2004) The degree to which natural forest stands are converted to homogenous conifer tree plantations is a significant metric contributing to simplification, or biodiversity loss, and uncharacteristic fire behavior. See Franklin and Agee 2003: "In many areas throughout western North America, uncharacteristic stand-replacement wildfires have been followed by reforestation programs that recreate the dense young forests, providing the potential for yet another stand-replacement fires." Also see attached PDF file:

References for issues on salvage logging and simplification
  • Lindenmayer, D.B., P. Burton, and J. Franklin. 2008. Salvage Logging and its Ecological Consequences. Island Press.
  • Mitchell, R.J.; Franklin, J.F.; Palik, B.; et al. 2003. Natural disturbance-based silviculture for restoration and maintenance of biological diversity. In: Final report to the National Commission on Science for Sustainable Forestry.
  • Sierra Nevada Ecosystem Project: Final Report to Congress. Davis: University of California, Centers for Water and Wildland Resources, 1996.

It is theoretically possible to miss most of the factors contributing to loss of biological diversity at the landscape scale through the use of inadequate habitat modeling devices such as the CWHR or similar conifer-centric habitat models. For a comprehensive literature review of the broad brush/fine grain issues, see the list of references below.

References for Wildlife Monitoring: Coarse Grain versus Fine Grain Issues
  • Biber, E. 2011. The problem of environmental monitoring. University of Colorado Law Review, 83:1, 2011.
  • Committee of Scientists on the internet at http://www.fs.fed.us/news/news_archived/science/
  • Cushman, S.A., K.S. McKelvey, C.H. Flather, and K. McGarigal. 2008. Do forest community types provide a sufficient basis to evaluate biological diversity? Frontiers in Ecology and the Environment 6:13-17.
  • Cushman, S.A., K.S. McKelvey, B.R. Noon, and K. McGarigal. 2010. Use of abundance of one species as a surrogate for abundance of others. Conservation Biology 24:830-840.
  • Schultz, C.A., T.D. Sisk, B.R. Noon, and M.A. Nie. 2012.Wildlife conservation planning under the United States Forest Service's 2012 planning rule. The Journal of Wildlife Management. doi: 10.1002/jwmg.513
  • Flather, C.H., K.R. Wilson, and S.A. Shriner. 2009. Geographic approaches to biodiversity conservation: implication of scale and error to landscape planning. Pages 85-12 in J.J. Millspaugh and F.R. Thompson, III, editors. Models for Planning Wildlife Conservation in Large Landscapes. Academic Press, New York.
  • Keane, J. J. 2013. 2013. California spotted owl: scientific considerations for forest planning. Pages 302-325 in Science Synthesis to support Forest Plan Revision in the Sierra Nevada and Southern Cascades. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 504 p.
  • Noon, B.R., K.S. McKelvey, and B.G. Dickson. 2009. Multispecies conservation planning on U.S. federal lands. Pages 51-84 in J.J. Millspaugh and F.R. Thompson, III, editors. Models for Planning Wildlife Conservation in Large Landscapes. Academic Press, New York.
  • North, M. and P. Manley. 2012. Managing forests for wildlife communities. Pages 73-80 in North, Malcolm, ed. 2012. Managing Sierra Nevada Forests. Gen. Tech. Rep. PSW-GTR-237. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 184 p.
  • Schlossberg, S. and D.I. King. 2009. Modeling animal habitats based on cover types: a critical review. Environmental Management 43:609-618.

Recently, Swanson et al (2010) have initiated the correct forestry science conversation needed to accurately describe the status of forests that have been managed under an intensive agriculture model for a century. Armed with this knowledge, in this assessment we will now include plantation data as a discrete field rather than a proxy for early natural forest stands.

There are also some individual species, usually those that are wider ranging and carnivores that provide good representatives to assess whether species can move readily across the landscape. The Pacific Fisher and California spotted owl are two such species.

Other habitat types support distinct species communities and the ecological integrity of these habitats can be effectively assessed using groups of species, such as birds. Partners in Flight and other conservation groups have developed habitat-specific focal species monitoring and management plans (Chase and Geupel 2005, Wiens et al. 2008) that describe the species best suited for monitoring and assessing the integrity of a large variety of habitats. Lists and descriptions of these focal species can be viewed here: http://www.prbo.org/calpif/data.html, and include plans focused on coniferous forest, riparian and other habitats, as well as a conservation plan for the entire Sierra Nevada (Siegel and DeSante 1999).

This assessment is purposely a compilation of readily available, existing information. There are several primary sources of information on vegetation and habitat types in California. First, is the existing vegetation layer (EVEG) that is developed across all lands by the US Forest Service in coordination with FRAP. Second, the national FIA plots that are laid out on a systematic grid are available. These were the two primary sources of information for this assessment. Fire as a process, is described in more detail in the Drivers and Stressors Chapter, but information from that section is utilized here. Information on connectivity associated with the California spotted owl and forest carnivores are available in databases that the state of California and the US Forest Service maintain, as well as with scientific projects including those of the Center for Biological Diversity, university and agency researchers and others described in the sections on these indicators of connectivity below. For a wider group of birds, occurrence data are widely available from throughout the Sierra Nevada National Forests through an ongoing monitoring program on forest chaparral, and riparian habitats, plus an associated data base and interactive web-based tool (the Sierra Nevada Avian Monitoring Information Network, http://data.prbo.org/apps/snamin/) that can assist current planning efforts and assess management actions on ecosystem integrity now and into the future.

Conditions related to function/services

Ecological integrity can be characterized in countless ways. In the chapter introduction, the complementary concepts of using natural range of variability and indicators related to ecosystem services were described. The natural range of variability assessment is in progress and will be incorporated in the next phase when trends are incorporated. The measures for ecological integrity that are described here include both those that will be incorporated into the natural range of variability assessment, as well as those that are not feasible to be addressed in this way (i.e. owl populations). In order to make the assessment meaningful and “doable” the focus was on those conditions that are the focus of ecosystem services and with available interpretations.

Key Ecological Integrity Characteristics/Measures


A conceptual model of how key components and processes of terrestrial ecosystems interact was utilized to frame which indicators were important to assess. This is an approach recommended by Noon (2003) to develop ecosystem monitoring indicators. In adaptive management, there is a continual iteration of assessment, monitoring, and planning. It makes sense to apply the same conceptual model to the assessment as the monitoring phase. The intent was to develop a framework that is concise, and not overly complex, which highlights the most important conditions and processes that influence ecosystem function and services. Numerous conceptual models could be derived, and this one is meant to be simple, doable and based upon the history of management issues and concerns in the bio-region.

Selection of indicators and measures was based on a conceptual model framework (see figure below for terrestrial ecosystem) as recommended by Noon (2003).The interactions of processes and components of ecosystems across the landscape were considered and the processes that strongly influence ecosystem functioning, sustainability and resilience were selected. For example, fire is a key ecological process that shaped terrestrial and riparian ecosystems in the bio-region (van Wagtendonk and Fites-Kaufman 2006).

Characterizing ecosystems is like painting a landscape; each artist may paint the landscape differently. Similarly, the ecosystems of the bio-region can be looked at with a “broad brush” or with fine detail. In this assessment, the broad brush approach or “coarse-filter” approach is applied across a broad landscape. Rare ecosystems with great significance such as aspen or giant sequoia forests will be considered. North and Manley (2012) suggest that “coarse filter” approaches “fail to account for the different spatial and temporal scales at which species may respond to forest conditions “. Many of the over 900 potential species of concern are endemic and have limited distributions (Chapter 5, WIKI). Since this is a regional and landscape level assessment we will not use a fine filter for most species. However, the conceptual aspect of focal species that may be in common across the bioregion is important (Schultz et al. 2013) to ensure that the assessment assembles existing information on species that may be important for impact analysis in the forest plans.

Ch1_Terrestrial_Eco_Influences_Dynamics.jpg
Conceptual Model Framework indicating key pathways among the ecological elements considered, and drivers and stressors.


Figure: Conceptual Model Framework indicating key pathways among the ecological elements considered, and drivers and stressors.

Biodiversity, living organisms, plants, mammals, birds, insects, fungi, even bacteria, and the unique communities they occur in, are integral components of ecosystems. Their integrity is central to overall ecosystem integrity, which also includes the non-living parts (e.g. air, rocks, water) and the processes that link them together such as carbon cycling. It is a monumental task to assess all aspects of biodiversity. The planning rule addresses two levels of biodiversity: coarse-filter and fine-filter. The draft planning directives provide further direction on coarse-filter and fine-filter elements to address. We have included coarse-filter, fine-filter, and intermediate filter-levels for this assessment. For some characteristics, such as connectivity of old forest, we have integrated both coarse-filter and fine-filter aspects. For example, connectivity of old forest is measured using habitat and distribution for spotted owls and forest carnivores (fisher and pine marten) that serves as both a coarse-filter, landscape measure as well as fine-filter since spotted owls and forest carnivores serve as examples of potential “focal species” as top food-chain (carnivore) species that are often sensitive to environmental changes from large fires, or land-use.

The table below illustrates using the conceptual framework; a combination of available coarse, intermediate and fine filters, existing information; the following set of measures were selected to focus the assessment. Larger scale conditions and processes such as habitat patterns, connectivity for limited habitat types (old forest and early seral, especially recently burned) and wide-ranging species, respond to ecosystem processes.


Ecological element
Measure
Source
Fine Filter
Species Presence? important for TES
Species distribution, condition, and threats
Species of concern assessment (Chapter 5 WIKI)
Focal Species
Conceptual model
Scientific literature (i.e. Shultz et al. 2013)
Avian focal species abundance and composition
California partners in flight habitat conservation plan focal species group abundance
http://www.prbo.org/calpif/data.html

http://data.prbo.org/apps/snamin/ by
Coarse Filter
all species (coarse-filter biodiversity); amount and distribution of habitat types
% of landscape by California Wildlife Habitat Relationship Types
US Forest Service Remote Sensing Lab existing vegetation maps, and FRAP maps
Distribution of limited habitat types
aspen, oak/hardwood, burned forest, giant sequoia, bristlecone pine, sagebrush, meadows, montane chaparral
RSL/FRAP/fire severity maps
Connectivity of old-forest species (coarse filter) habitat and geneflow potential
old forest amount, patch size, distribution, distribution of sage grouse, goshawk, spotted owl, fisher and pine marten.
Spencer et al. 2012; Franklin and Fites-Kaufman 1996; Natural Resource Information System, California Fish and Wildlife Dept. and US Fish and Wildlife
Connectivity of early seral and non-forest patches.
early forest amount, distribution and type;
USFS Remote Sensing Lab existing vegetation and Fire Severity Monitoring Program Data.
Fire as an ecological process: (1) regulate carbon and (2) fire resiliency, (3) creates or enhance habitat for fire dependent species, and (4) enhanced flora and fauna diversity.
Proportion of landscape burned at different fire severity levels (composite burn index); Fire return interval departure; Fire resilience
R5 Fire Severity Monitoring Program; Safford and xxxx, Chapter 1 and 3 WIKI, literature
Process: vegetation growth (succession) carbon cycling, nutrient cycling, productivity
Changes in above ground biomass, and live and dead vegetative carbon. Net decomposition.
FIA plots, changes over time in biomass and litter and woody cover.
Intermediate Filter
plant diversity; animal; fungi; invertebrate; other lifeform diversity :
amount and distribution of microhabitats, within patch diversity/heterogeneity
GTR-237; FIA plots – within plot variability of canopy cover, tree density, shrub cover, gaps
Dead wood habitat : Snags, coarse woody debris
tons/acre, density by size and decay class
FIA plots
Tree composition: relative density of functional groups (hardwoods, pines, shade tolerant)
tree density by species and layer
FIA plots
Process: old forest dynamics. large tree recruitment and mortality
Density of medium and large diameter trees; % mortality by diameter by species? By year
FIA (existing analysis), GTR-237 by subregion, ecological zone, vegetation type

Selected key ecological integrity indicators/measures are focused on:
  • broad scale, or “coarse-filter” patterns in vegetation composition and structure,
  • connectivity and habitat for wide-ranging carnivores (fisher, marten, California spotted owl and goshawk), *any shrub equivalent? suggest we use sage grouse for sagebrush
  • habitat elements that are important to many biota (i.e. snags and large trees) and may be limited in areas, *others may include cavity trees; willow cover in meadows
  • habitat conditions that have been altered by management in the last 100 years (e.g. suppression of fire as a process), such as within-patch heterogeneity or variation in vegetation structure and composition
  • habitat diversity important for specific groups of plants and animals.
  • California Partners in Flight habitat conservation plan focal species abundance
  • Biodiversity as reflected in multi-species (avian, invertebrates, mammalian, herps, or other) indices such as: richness, Shannon-Wiener/Simpson/other diversity metrics, and other measures including genetic markers
  • Ecological Groups, Guilds or Assemblages that provide an intermediate level between very broad coarse-filter measures and individual species as components of ecological integrity. Specifically, these allow an intermediate measure of ecological integrity centering on biodiversity. It is particularly useful in relevant assessment of species of concern as well as common or ecologically significant species such as "ecosystem engineers".


Current Condition


Ecological Integrity – Natural Range Of Variability Of Vegetation, Fire, Insects/Pathogens

A primary assumption of the new planning rule is that “natural range of variability” is a key means for gauging ecological integrity. This is based upon extensive scientific writing on the subject. The main ideas is that efforts to achieve ecosystem sustainability and persistence are likely to be more successful if they maintain ecosystems within the bounds of natural variation (NRV) rather than targeting fixed conditions from some point in the past, such as historic conditions (Wiens et al. 2012). Safford et al. (2013) compiled comprehensive, scientific literature reviews on NRV, with only key points summarized here.

The foothill ecological zone occurs at the lowest elevations, comprised of chaparral, blue oak savannahs, live oak woodlands and forests, narrow riparian stringers along rivers and streams, seeps, and scattered gray pine or occasional patches of knobcone pine (Barbour and Schroer 2007). Overall, the vegetation and fire patterns in this zone are outside of the range of variability (Estes 2013, Merriam 2013, and Sawyer 2013). The foothill zone is amongst the most altered, and fragmented by land-use (urbanization and agricultural conversion) and mostly below the western boundaries of national forests (Sierra Conservancy 2011). Vegetation is mostly out of NRV with persistent nonnative species, urbanization, water development, changed fire regime, and agricultural uses as the primary causes.

Ponderosa pine, black oak, mixed conifer, riparian forests and to a lesser extent chaparral and meadows comprise the vegetation mosaic in the westside montane zone (Fites-Kaufman et al. 2007), and occupy the greatest extent in the bioregion (7.5 million acres including eastside types and upper montane Jeffrey pine). Composition, structure, and fire regimes have changed considerably since presettlement times and are largely outside of NRV (Safford 2013, Merriam 2013). Pines and oaks have decreased substantially and shade tolerant species (cedar and fir) have increased. Forest density is higher, canopy cover of trees more uniformly higher, small and medium tree density is higher and large tree density is lower. Within stand variation (heterogeneity) in tree sizes and density is decreased. Climate has been wetter, with fewer droughts in the late 19th and 20th centuries than earlier periods (Safford 2013). This means that pre-settlement forest conditions may not reflect what will be resilient forests in the near future with projected drying, and warming climate. Fires are less frequent but there is some evidence that they are larger, or certainly more severe in large uniform areas, than presettlement. Changes in fire have contributed to contractions of interspersed chaparral patches (Estes 2013a), and black oak patches and trees (Merriam 2013). Overall resilience of the forests to drought and fire has changed considerably (Safford 2013). Increases in chaparral and hardwood vegetation will most likely occur at lower reaches of the zone. Some evidence exists that this has already occurred in steep, river canyons in the southern Sierra Nevada (Kern and King River canyons), in the central area (Merced, Tuolumne and Stanislaus River canyons), and is now progressing north into the Feather River Canyon. The forest zone gets pushed up, compared to where it could grow (Sugihara, personal communication 2013). Giant Sequoia (National Parks, Tahoe, Stanislaus, Sierra and Sequoia National Forests) is particularly vulnerable to climate change, with wetter areas it depends upon expected to shrink (York et al. 2013 and Giant Sequoia National Monument Plan).

Red fir forests, Jeffrey pine woodlands, lodgepole pine forests, meadows, alder patches, herbaceous patches and chaparral create a diverse mosaic in the upper montane ecological zone (Fites-Kaufman et al. 2007). Red fir forests are both within and without NRV (Meyer 2013a) and are amongst the most vulnerable to climate change (NPS 2013, TACCIMO 2013). Structure has shifted with homogenization at stand and landscape scales, increases in small and medium trees, and decreases in large trees. Fire return intervals have lengthened but total area burned has increased since 1984. Recent increases in mortality associated with moisture stress, insects and pathogens suggest that they may move outside NRV soon. Up to an 80% loss of red fir is projected with snowpack declines, which is already declining and expected to decline more with climate change. Aspen and meadows are occur in wetter areas and are particularly rich in plant and animal diversity (Estes 2013b). Some aspects of aspen are within NRV and many outside of NRV. Plant composition and diversity appear to be largely within NRV but extent has contracted and fragmented. Grazing, water development and fire suppression have had various effects on composition, structure, and distribution. Regeneration and structural diversity have declined. Meadows and riparian communities are both within and outside of NRV. Very little scientific information on NRV for meadows exists (Gross and Coppoletta 2013). Early extensive grazing prior to 1930 was intense and concentrated in meadows, along with other land-uses resulted in a large number of incised stream channels, reducing small flood events and wetland species. Species composition has also shifted outside of NRV where nonnative invasive species have been introduced (e.g. dandelion). Fire suppression has contributed to conifer invasion on meadow edges, but there is uncertainty how much of the invasions are related to periodic, long-term fluctuations in climate. Current livestock grazing levels are considerably lower, with overall biomass of most meadows within NRV. Meadows are vulnerable to climate change (Hopkinson et al. 2013). As with meadows and aspen, there is limited scientific information on NRV of chaparral in upper montane landscapes (Estes 2013a and Meyer 2013). Changes in fire regime from suppression and land-use have decreased shrub patches but composition is thought to be within the NRV.

Subalpine forests are largely within NRV (Meyer 2013). There have been some shifts in structure toward higher density stands and a decrease in large diameter pines due to climate warming and and logging in the 19th century. Fire return intervals have lengthened but total area burned has increased in some types since 1984. Overall fire regimes are within NRV at this time but with climatic change are projected to increase in frequency, area burned and severity. Increased mortality of western white pine from white pine blister rust has occurred but otherwise mountain pine better outbreaks have likely not changed. There has been an upward migration of some species into alpine zones, and growth, such as bristlecone pine, beyond the natural range of variability, likely due to increased temperature. Subalpine forests are considered vulnerable to climate change (Eschtruth et al. 2013; TACCIMO 2013) and are projected to decrease by up to 85% or more by the end of the century.

Eastside yellow pine and mixed conifer forests are in similar condition to westside montane pine and mixed conifer forests (Safford 2013). Structure and fire regimes outside of NRV, with denser trees, more uniform forests, and larger, higher intensity fires. The 2012 Barry Point fire that burned 93,000 acres in Modoc County and into Oregon (http://www.inciweb.org/incident/3105/) is an example. While frequent fires were once common place in the dry, flatter, lightening prone landscapes common east of the Sierra Nevada and southern Cascades, rarely were they so uniformly intense. Plant composition has changed, but most species are still present. There has been a large departure in vegetation from invasive plants, especially cheatgrass which has become established across large swaths.

Pinyon-Juniper woodlands and sagebrush are prevalent across the eastern portion of the bioregion, dominating where it is driest (Slayton 2013a, b). There are aspects of these types that are in NRV and others that are far outside of NR. Research on some aspects is extensive (pinyon-juniper invasion and cheatgrass) but there are many uncertainties in other aspects. Current patch structure and composition are within NRV but landscape patterns are not. Early seral habitat is lower, non-native cheatgrass has displaced native plants and entire patches of sagebrush, and pinyon-juniper has increased. Fire regimes are partially outside of NRV, with less frequent fires in some areas, and more frequent fires where cheatgrass has invaded. Desert species are encroaching from the south, and with climate change fire activity will increase. Pinyon-juniper has always migrated with climate change, but fire suppression and grazing have enhanced the process, expanding the distribution recently. Stands on sites with shallow soils remain stable, but on other sites climate change will increase fire, and increase cheatgrass invasion.

Vegetation Dynamics And Carbon Cycling Processes

Just like people, families and communities, forests, shrublands, and grasslands grow over time, and change in size, numbers and mixtures. In ecological terms, this is “vegetation dynamics” or succession. An important aspect of vegetation dynamics is how carbon balances or flows through ecosystems, or carbon cycling. Extracting oil to use in cars and industry, with some that is emitted back to the atmosphere and affects global weather is one example. With natural ecosystems, plants and fires play important roles. Plants use carbon dioxide from the air in photosynthesis to build sugar, and grow. When they die and break down (decompose) or burn, they release carbon dioxide back to the air. Equally important or more important in dry, fire prone ecosystems than uptake or “sequestration” of carbon by growing plants, is the resiliency of forests to intense fires which release vast amounts of carbon rapidly into the air. In this section, we consider the changes or dynamics of vegetation growth and density, and implications for carbon cycling, key aspects of resiliency, sustainability and ecological integrity of ecosystems, based primarily upon the 2013 science synthesis (North Chapter 2, Collins and Skinner Chapter 4.1, Moghaddas Chapter 5), topical papers for the bioregional assessment (Chapter 1, 3, 4, 8, WIKI), and other key recent research papers.

A large portion of the bioregion, the montane pine and mixed conifer forests, are relatively productive in terms of vegetation growth but because they are dry, decomposition or breakdown is slow. This means that dead plant material continues to accumulate over time in the absence of fire (Stephens et al. 2012). Re-measurement of permanent Forest Inventory Plots (FIA) show consistent increase in tree biomass (measure of growth) alone that exceeds removal from decomposition, fire, or thinning by a significant margin (Chapter 3, WIKI; USFS Westcore Tables 2012; Fried personal communication). This results in increasing fuels for fire and likelihood of high intensity crown fires (Stephens et al. 2012) and likelihood of widespread insect outbreak (Sierra Conservancy 2012a) beyond NRV levels (Chapter 3, WIKI).

Fire played an important role as an ecosystem process in “regulating” forest structure and density (Collins and Skinner 2013: Science Synthesis Chapter 4.1). Previously, attention was focused on sequestration of carbon from younger, fast growing trees but newer studies found that old forests and large trees continue to sequester carbon and store more carbon than younger stands (North 2013: Science Synthesis Chapter 2). The concept of carbon carrying capacity (Keith et al. 2009) emphasizes carbon stability and is particularly relevant in dry, fire prone forests, such as in the bioregion. Historical forests may have been less dense, but stored more carbon in the higher numbers of large trees (North 2013: Chapter 2 Science Synthesis).

Offsets to reduced future wildfire carbon emissions from treatments (mechanical, prescribed and managed fire) has been debated in the relative tradeoffs (North 2013). These are based largely on uncertainties with smoke emissions (Bytnerowicz et al. 2013: Science Synthesis Chapter 8) and carbon cycling estimates. Recent research from long-term plots in areas treated with prescribed fire and thinning to reduce fuels in the bioregion have demonstrated that there is a significant offset in potential emissions from high intensity wildfires that last at least 8 years (Vaillant et al. 2013). This corroborates findings from more localized areas (Hurteau and North 2010) and other areas (Boerner et al. 2008, Hurteau et al. 2011). But with less intensive treatment the recovery is faster (Vaillant et al. 2013).

The rate of vegetation change and carbon dynamics is a vital consideration with restoration. One restoration treatment entry is ever sufficient. The rate of vegetation response can yield positive and negative ecological integrity outcomes. Vaillant et al. (2013) found that understory shrub cover recovered within 5 to 8 years of both burning and thinning in monitoring plots in the bioregion—important habitat components for many birds, small mammals and their food and “housing” requirements (leaves, fruits, branches, and insects). In turn, these smaller animals are important prey for predators, often of concern, including owls and goshawks. But tree seedlings also rapidly recover and the cycle of increased forest density goes on. Thinning may not sufficiently reduce surface or ground fuels to change fire intensity (Vaillant et al. 2013) to desired levels, and may need follow up prescribed fire.

Vegetation Conditions – Coarse Filter

Vegetation structure and composition at the broad scale are represented here by the California Wildlife Habitat Relationships (CWHR) types. These are broad categories of habitat based upon dominant plant species, density (usually canopy cover), and average size of trees or shrubs. In the case of trees, it is the average diameter of trees. This is a classification that has been widely used by California state agencies and federal agencies such as the Forest Service. For individual wildlife or plant species of interest, these types may not always characterize the habitat as specifically as current science identifies (North 2012-GTR 237), it is the best available vegetation information that encompasses the entire area. It does provide a reasonable “coarse”, big picture view of vegetation condition.


For the purposes of this assessment, some of the categories of vegetation were combined to make it useful. For example, Jeffrey pine and ponderosa pine cover types were combined into a single yellow pine cover type. Another example is collapsing of seedling and sapling tree size classes into one young size class. The ways these categories were combined is detailed in the appendix.

These methods do not incorporate the use of a necessary new habitat category, the agriculture/plantation category. This category is necessary to accurately distinguish between natural forest development in the region, and agricultural tree cropping systems. It is no longer acceptable to merge most plantation acres with conifer age classes, particularly where these resulted from standard methods of salvage logging, planting, and herbicide use. See Mitchell et al 2003, Franklin and Agee, Lindenmayer et al 2008, and Swanson et al 2010, as referenced above.

Plantation acres will not contribute either early successional or late successional attributes to the bioregion within the foreseeable future on private industrial timberlands and FS lands where prior management emphasized homogenous conifer plantings over natural succession and native plant diversity. It’s important to note what percentage of the landscape is in that condition in this assessment.

Depictions of broad vegetation patterns, including lifeforms (forest, shrub, grassland etc), density (canopy cover), and average size (tree diameter) were summarized from the Existing Vegetation map layers developed by the US Forest Service Remote sensing lab. These maps are developed using a combination of remote sensing data (from LANDSAT satellite images) and field plot data (xxxxx). They cover all lands and are available on xxxxx website. They are periodically updated, approximately every five years, with new satellite images and maps of large fires. Their primary purpose is for broad-scale analysis, and not detailed site-specific views of vegetation.

The data from the maps were separated by the ecological subregions and in some cases ecological zones that were described previously. Additional information on vegetation condition is currently being summarized from detailed ground plots, the national forest inventory and analysis plots, but is not available at this time. Using the plot data, additional indicators will be summarized that were identified such as within stand variability in vegetation structure and successional patterns.

There are both common patterns and obvious contrasts in the vegetation patterns amongst the different subregions across the assessment area. The vegetation type maps highlight some of the major changes that occur from west to east and north to south.

Southern Sierra Subregions, West and East
In the southern Sierra Nevada, the higher elevation of the mountain crest results in noticeable changes with elevation from a large area of oak woodlands and chaparral on the western slopes, up into mixed conifer, where the remarkable giant sequoia grows, to red fir and then a relatively large band of high elevation subalpine and alpine vegetation. Moving down the east slopes, there are more rapid transitions from one vegetation type to another and a large area of Great Basin and Mojave desert influenced pinyon-juniper, sage scrub and desert vegetation. Notable at the higher elevations in the mountains on the eastern edge of the Inyo National forest, are the Bristle cone pine forests. The southernmost portion of the bio-region, is transitional to the more open, xeric and desert like vegetation of Southern California mountain ranges.

Southern Sierra Nevada
The largest expanse of western slope hardwoods occurs within national forest boundaries in the Southern Sierra Nevada within the Sierra and Sequoia National Forests. This is significant because the oak woodlands are amongst the most fragmented and developed vegetation types in California. Canopy cover is greater on the west slopes of the Sierra Nevada than in the higher elevations, although in general extensive areas of dense forest are less prevalent in the south than in the north, where higher average precipitation is common.
On the west slopes, most of the forests are mid-sized, with average diameters of 12 to 24” dbh. Areas with larger average diameters, >24” are distributed throughout. The giant sequoia groves contribute to these patch types, with almost half of the mixed conifer classified as late seral (USDA 2012: p. 65). In the groves, diameters of trees exceed those in any other forest in the Sierra Nevada.

ADDTEXT HERE

Existing vegetation patterns in the Southern Sierra Nevada, west of the mountain crest. Based upon remote-sensing (LANDSAT) derived maps produced by the US Forest Service Remote Sensing Lab. CWHR is the California Wildlife Habitat Relationships classification commonly used in the state on all lands.

View WHR Type, Description, Group, Species, and Lifeform Classes PDF in a new window


South - Southern Sierra Nevada
EcoType_South.jpg
aChap1_Bio_Lifeform_South.jpg
cwhrdensitysosn.jpg
cwhrsizesosn.jpg
aChap1_Bio_SizeDensity_South.jpg


Eastside – Southern Sierra Nevada
EcoType_East-South.jpg
aChap1_Bio_Lifeform_EastSouth.jpg
cwhrdensityeastsouthsn.jpg
cwhrsizeeastsouth.jpg
aChap1_Bio_SizeDensity_EastSouth.jpg

Central Sierra Nevada
EcoType_Central.jpg
aChap1_Bio_Lifeform_Central.jpg
cwhrdensitycentral.jpg
cwhrsizecentral.jpg
aChap1_Bio_SizeDensity_Central.jpg

Northern Sierra Nevada and Southern Cascades – Westside
EcoType_North.jpg
aChap1_Bio_Lifeform_North.jpg
CWHR_Density_North.jpg
CWHR_Size_North.jpg
aChap1_Bio_SizeDensity_North.jpg

Northeast Sierra Nevada, Southern Cascades and the Modoc Plateau
Ch1_Terrestrial_CWHR_Type_EN_sm.jpg
Ch1_Terrestrial_CWHR_Lifeform_EN_sm.jpg
Ch1_Terrestrial_CWHR_Density_EN_sm.jpg
Ch1_Terrestrial_CWHR_Size_EN_sm.jpg
Ch1_Terrestrial_CWHR_SizeDen_EN_sm.jpg

Ecological Integrity – Biological Diversity


This section focuses on the fine-filter level of biodiversity, individual species or groups of species in limited habitats. Information is limited and draws from the topical papers on Species of Conservation Concern (Chapter 5, WIKI) and Ecological Integrity (Chapter 1-Terrestrial Ecosystems, WIKI). Focal species, individual habitat elements (i.e. snags, large trees, within forest heterogeneity and understory plant patches), and limited habitats (i.e. aspen, recently burned forests) are discussed.

Over 1000 species were considered (1077) (Chapter 5 WIKI) but is an overestimate of what occurs on the national forests since data came from county or map quadrangle levels. Careful review and evaluation at the forest scales, to determine what occurs within national forest boundaries is currently underway. At this time, preliminary information (overestimate) includes over 100 threatened and endangered species, including: 30 fish, 19 amphibians, 98 invertebrates, 41 birds, 6 reptiles, 33 mammals, and 505 plants. The final list of species of concern will be decided upon by the regional forester, once the revised potential list is completed.

The concepts of management indicator species, keystone species or other terms used to identify a few number of species to represent impacts of management or environmental stressors (e.g. climate change) with changes to the habitats they represent is controversial. In the new planning rule, the concept of focal species is proposed with the intent to pick a reasonable number of species to evaluate and monitor over time. Noon et al. (2009) and Schultz et al. (2013) suggest criteria and processes for selecting focal species: base on a conceptual model of ecological processes and functions; include species that are indicators to key stressors, play a role as engineers of ecological processes, play an important role in food web dynamics, and are threatened/at risk/rare species; using a formal process. We provide some examples that meet the criteria proposed, some also addressing coarse-filter connectivity issues. Here, emphasis is on land-based species (terrestrial), water-based (aquatic) species are covered in the previous water section.

Spotted owls, fisher, pine marten, sage grouse, aspen, and large trees meet several of these criteria and also help assess landscape connectivity for key habitats: old forest and eastside sagebrush. All are at risk, rare or threatened, sensitive to stressors (i.e. high severity, large fires), and important in food web dynamics. Additional species, or fine-filter elements meeting multiple criteria include: large, especially old trees (habitat engineers, limited or rare, at risk); woodrats (important prey, nests are home to hundreds of insects and many reptiles); and woodpeckers (engineers of cavities used by many species -flying squirrels and cavity nesting birds); large snags (critical habitat for many species, often limited or very patchy due to past management); and amphibians (sensitive to climate change, air quality stressors, changes to riparian and aquatic ecosystems). Other engineers playing critical roles in ecosystem processes include carpenter ants (initial decomposition of large woody debris, and food source for many), fungi (mychorrizal relationships with trees and other plants), and bees (pollination and sensitive to stressors). In addition to focal species, for some taxa, community composition, or all of the co-occurring species in an area, are also useful. For example birds in various habitats (Chapter 1 WIKI) from Partners in Flight (http://www.prbo.org/calpif/). For plants, selections might include: cheatgrass (invasive grass that is a major stressor, changing fire regimes, soil fungi composition and levels, and constricting habitat of native and some key endangered species—i.e. sage grouse); aspen (at risk from fire suppression and other stressors, associated with rich and diverse floristic assemblages, critical habitat for numerous bird species); or forest understory plants requiring sunlight in small patches, particularly those with life histories enhanced by fire (fire stimulated flowering such as bearded penstemon or many lilies- Fites-Kaufman et al. 2006) that are stressed by fire deficits. A synopsis of current condition, trends and implications for restoration for large trees, snags, special habitats, and overall within-forest habitats are below. Some aspects were referred to previously in the NRV discussion.

Snags and large trees are highly variable in the landscape. Overall, large tree density and extent vastly is lower compared to historic conditions, particularly for foothill and montane pine and mixed conifer forests. Recent, large high severity fires have further reduced large trees, often old trees (>200 years old) that will take a very long time to replace. Recent concentrations of these fires on the Plumas and Lassen National Forests (Chips, Antelope, Moonlight fires) have resulted in large areas that had few large trees to begin with and now have only scattered remaining large trees. Large tree mortality and vigor have been reported, particularly in the southern Sierra Nevada, attributed to combined causes of increased forest density (vulnerability to moisture stress), ozone, and climate change (Van Mantgem and Stephenson 2007).

Snag densities and sizes are highly variable. In unburned forests, large snags tend to be low density, and smaller snags can be higher density, but in burned forests, there may be extensive areas of snags of all sizes in concentrations atypical of NRV (areas of large extent) (Safford 2013). The latter pattern is most prevalent in montane pine and mixed conifer forests but more uncommon and uncertain as to the status relative to NRV in upper montane forests (Meyer 2013).

Information on the occurrence and extent of specific habitats (contrasting with coarse-filter) is limited and the ecological condition is more uncertain than for common forest types. They are important to consider because they often serve as “hotspots” for uncommon, rare, or diverse assemblages of species. Similarly, understory herbs and grasses, often occur in patches at a fine-scale that is not mapped, such as forested openings, limestone rock outcrops, or fens. These elements of biodiversity will be covered in more detail at the individual forest scale, where it is possible to distinguish and describe them adequately. Here we display examples of the rich array that occur across the bioregion and distributions that cross land ownerships and administrative forest boundaries. Aspen and meadows are particularly vulnerable to climate change and in the dry Mediterranean and Great Basin climates of the bioregion, are important for many species of plants and animals. These were discussed in the NRV section as was montane chaparral, sagebrush, and oak/hardwood communities. Aspen depicted in this map is an overrepresentation because in its current, highly fragmented condition, it does not show up unless the locations are magnified (as we have done). Other special habitats, including Bristecone pine and giant sequoia illustrate the very limited distribution of these unique and well-loved plant communities. Recently burned patches can attract and support many species, in particular birds such as Olive-sided Flycatcher, Fox Sparrow, Yellow and MacGillivray’s Warblers, and Dusky Flycatcher , and black-backed woodpeckers (http://www.prbo.org/cms/docs/edu/NSierraShrub.pdf). They can provide both shrub rich environments as well as complex, early seral habitats (combination of post-fire shrubs, herbs, and legacy snags and logs). The pattern of recently burned areas is vastly different in montane forests than evidence from NRV indicates (Safford 2013). The patches are larger across continuous areas but vastly decreased as smaller patches, particularly within-stand scale (North 2012).

This uniformity, along with absence of low to moderate intensity fire, has resulted in a vast reduction in fine-scale forest heterogeneity or complexity. Small, sunny openings, favored by some plants are relatively rare. Areas cleared of dense, deep leaf and needle litter are uncommon, impeding germination of some types of plants. Shrubs and herbs that need sun and often fire to flower or develop vigorous foliage are scraggly or decadent. As a result, understory animals, such as rodents (mice, squirrels, woodrats) and songbirds, that depend on the plants in these small openings or sunnier, burned spots are decreased. The trend for homogenization and lack of fire to invigorate understory plants will continue. On the other hand, as discussed in the fire and NRV section, the trend is for larger patches of uniform, early aged, or early seral vegetation to develop after fire. This can be good for plants and animals associated with these habitats. But the patches are often very large, compared to historic patterns, and widely distributed in the bioregion, limiting movement of species between them, or connectivity.

Ch1_Terrestrial_Early_Seral_Veg.jpg
Ch1_Terrestrial_PctEarlySeral.jpg

Fine-Scale Vegetation Structure

Several measures were selected that are important to ecological integrity, have been affected by stressors or land-use, and for most have readily available information (as directed in the planning rule). These include within-forest heterogeneity (North xxxx), floristic fine-scale habitat (within patch), snags and large trees. These fall into an “intermediate” filter level of ecological integrity. Some additional limited habitat types of concern were also included. They are more general than individual species, but more refined than coarse-filter, broad habitat types or connectivity patterns. Detailed information on these characteristics are found in the topical paper on Ecological Integrity (Chapter 1, WIKI), and the Science Synthesis (Chapter 2; Forests: North 2013), North et al. (2009), and North (2012).


Vegetation Fine-Filter (Structure and Composition within Patches and Stands)


I. Within Stand Variation of Forest Structure of structural heterogeneity

Link to new page with graphs for Within Stand Variation of Basal Area for all Forests

II. Large Trees By Administrative Unit and Forest Type

Comparing Southern Sierra Forests


Inyo National Forest

Sequoia National Forest

Sierra National Forest

# of Plots
≥21
≥24
≥30
≥40
≥50
# of Plots
≥21
≥24
≥30
≥40
≥50
# of Plots
≥21
≥24
≥30
≥40
≥50
Conifer
240





247





312





Median

11.1
6.9
3.0
0.6
0.0

17.2
13.0
6.5
1.3
0.1

11.9
8.3
3.8
1.0
0.2
Mean

12.5
8.2
3.9
1.1
0.1

18.3
13.7
7.1
1.7
0.2

14.9
10.3
5.2
1.6
0.5
CV

55%
56%
72%
105%
162%

59%
56%
69%
106%
59%

96%
102%
122%
193%
221%
Conifer Hardwood
2





25





39





Median

6.0
6.0
2.0
0.7
0.0

16.0
6.0
1.0
0.0
0.0

8.0
4.0
1.0
0.0
0.0
Mean

6.0
6.0
2.0
0.7
0.0

18.0
9.5
4.1
1.0
0.0

8.2
5.6
2.9
0.9
0.2
CV

47%
47%
47%
141%
0%

90%
102%
129%
203%
500%

87%
106%
136%
217%
624%
Oak Woodland
3





56





70





Median

16.0
8.0
0.0
0.0
0.0

1.0
0.4
0.0
0.0
0.0

2.7
0.7
0.0
0.0
0.0
Mean

16.0
8.0
0.0
0.0
0.0

2.6
1.3
0.2
0.0
0.0

5.8
2.8
1.2
0.4
0.1
CV

100%
100%
0%
0%
0%

124%
113%
131%
88%
0%

168%
160%
201%
120%
211%
Riparian Wetland
13





5





9





Median

0.8
0.8
0.3
0.0
0.0

0.0
0.0
0.0
0.0
0.0

0.0
0.0
0.0
0.0
0.0
Mean

0.9
0.9
0.4
0.0
0.0

0.0
0.0
0.0
0.0
0.0

1.2
0.6
0.1
0.0
0.0
CV

153%
153%
153%
0%
0%

0%
0%
0%
0%
0%

182%
240%
300%
0%
0%

Link to new page with Large Trees for all Forests


III. Shade Tolerance by Ownership and Forest Type

Comparing Southern Sierra Forests

Inyo National Forest
Sequoia National Forest
Sierra National Forest

# of Plots
< 12
≥ 12
# of Plots
< 12
≥ 12
# of Plots
< 12
≥ 12
Conifer
240


247


312


Mean

7%
7%

26%
17%

26%
16%
CV

196%
198%

86%
107%

182%
240%
Conifer Hardwood
2


25


39


Mean

5%
0%

56%
35%

58%
28%
CV

141%
0%

75%
100%

64%
122%
Oak Woodland
3


56


70


Mean

9%
0%

32%
10%

51%
20%
CV

173%
0%

91%
107%

79%
156%
Riparian Wetland
13


5


9


Mean

0%
0%

46%
0%

67%
6%
CV

105%
0%

7%
0%

64%
300%

Link to new page of Shade Tolerance for all Forests

IV. Snags by Ownership and Forest Type

Comparing Southern Sierra Forests

Inyo National Forest
Sequoia National Forest
Sierra National Forest

# of Plots
≥ 15
# of Plots
≥ 15
# of Plots
≥ 15
Conifer
240

247

312

Mean

2.7

3.0

3.7
Median

1.1

1.3

1.3
St. Dev

5.5

5.6

6.1
CV

112%

101%

206%
Conifer Hardwood
2

25

39

Mean

0.7

2.7

2.6
Median

0.7

0.0

0.0
St. Dev

0.9

5.2

6.1
CV

141%

191%

233%
Oak Woodland
3

56

70

Mean

1.3

1.3

1.0
Median

0.0

0.0

0.0
St. Dev

2.3

4.3

3.2
CV

173%

64%

353%
Riparian Wetland
13

5

9

Mean

1.0

0.3

0
Median

0.2

0.3

0
St. Dev

4.2

0.4

0
CV

153%

71%

0

Link to new page for Snags for all Forests

INSERT Forest Inventory and Analysis (FIA) data on: forest heterogeneity; forest density; large trees; snags, logs; and dominant tree composition

V. Understory Floristic Diversity

The emphasis of this section is to address background on floristic diversity, including the ecology of plants, moss and other bryophytes, and lichens. Floristic diversity is very rich in California, including in the Sierra Nevada. In Chapter 5, Species at Risk, specific species are addressed that include threatened and endangered, management indicator species - Planning Rule dismisses use of MIS - will these still be included in Ch. 5?, or species of concern. As readily apparent in that chapter as well as the background below, there are hundreds of species of plants that are considered at risk. Given this enormous number, it is important to also assess a more “coarse-filter” view of floristic diversity; where we have measurable information. For a coarse-filter approach, we are using a “habitat guild” or “life history group” approach- most useful for addressing the large number of rare species that need to be discussed in Ch. 5 The indicator for rare communities/special habitat types, along with FIA and/or TEUI plot data, may be more useful for this Ch. 1 discussion of diversity?. This was utilized in the 2001 Sierra Nevada Forest Plan Amendment EIS (USFS 2001: Vol. 3, Chapter 3, Part 4, Section 4.6). The other primary source of information used in the background is from the scientific assessment by Dr. Shevock in the Sierra Nevada Ecosystem Study Project (1996).

Background Excerpt from Status of Rare and Endemic Plants from the SNEP Report
This excerpt paints a picture of California’s plant diversity; provides background for impact of invasives on California’s botanical treasures; shares unique, special places in California and glimpse of the value of plants for enjoyment of California’s people and future generations.

The Sierra Nevada represents nearly 20% of the California land base yet contains over 50% of the state’s flora. Approximately 405 vascular plant taxa are endemic to the Sierra Nevada. Of this total, 218 taxa are considered rare by conservation organizations and/or state and federal agencies. In addition, 168 other rare taxa have at least one occurrence in the Sierra Nevada. Five monotypic genera are endemic to the Sierra Nevada (Bolandra, Carpenteria, Orochaenactis, Phalacoseris, and Sequoiadendron). Information on rarity and endemism for lichens and bryophytes for the Sierra Nevada is very speculative and fragmentary due to limited fieldwork and the small number of available collections. Two mosses are endemic to the Sierra Nevada. Parameters obtained for each rare and/or endemic taxon include habitat type and distributions by county, river basin, and topographic quadrangle. Distribution information for many taxa remains incomplete based on limited field studies and vouchered specimens, especially in the more unroaded and rugged areas of the Sierra Nevada. Rare and endemic species are not evenly distributed throughout the Sierra Nevada. The Kern, Kings, Merced, San Joaquin, Tuolumne, and Feather River Basins contain the largest concentrations of rare and endemic taxa in the Sierra Nevada. For the eastern slope of the Sierra Nevada, the Owens River Basin is rich in species composition as well as rare and endemic taxa. Of the three geographical subunits, the northern, central, and southern Sierra, the southern Sierra is extremely rich in endemics, rare species, and total floristic composition. Adverse impacts to some Sierran rare plants are occurring along the western fringe of the range adjacent to the Central Valley, where conversion of lands to agriculture and urbanization may greatly restrict or alter essential habitat for some Sierran endemics and/or rare species.

For more than 100 years, the flora of the Sierra Nevada has fascinated botanists even beyond the borders of the United States. Visions of Yosemite, giant sequoias, and extensive mixed conifer forests have added to an awareness of this magnificent mountain range. The Sierra Nevada, part of the California Floristic Province, is characterized by high rates of plant endemism (Stebbins and Major 1965; Raven and Axelrod 1978; Messick 1995). For most of this century, plant collecting and floristic research remained the pursuits of professional botanists with ties to major scientific and educational centers (Shevock and Taylor 1987). Floristic studies have as one of their primary goals documentation of all the taxa (species, subspecies, varieties) for a particular geographic region and determination of their distribution and abundance within that study area (Palmer et al. 1995). Rare, endemic, and disjunct taxa have a special place in such studies because they contribute to the diversity and uniqueness of a flora. Remarkably, the Sierra Nevada lacks a comprehensive floristic treatment. Portions of the range are covered by a great variety of floristic studies, ranging from detailed floras to florulas and checklists. Floristic studies generally fall into four categories: county floras (Clifton 1994; Oswald 1994; True 1973; Twisselmann 1967), floristic tudies by watershed (Henry 1994; Lavin 1983; Palmer et al. 1983; Savage 1973; Shevock 1978; Smith 1973, 1983; Taylor 1981), studies based on park or preserve boundaries (Gillett et al. 1961; Knight et al. 1970; Potter 1983; Pusateri 1963; Rice 1969; Showers 1982), and studies by specific topographical features and habitats (Forbes et al. 1988; Howell 1951; Hunter and Johnson 1983; Sharsmith 1940; Smiley 1921; Tatum 1979; Williams et al. 1992 Much acreage remains in the Sierra Nevada that is not botanically surveyed or systematically vouchered, especially in unroaded or relatively rugged areas.

With the passage of the federal Endangered Species Act of 1973 (ESA, as mended) came a distinct shift in plant collecting and subsequent conservation efforts toward a focus on those taxa believed to be candidates for threatened or endangered status. These distribution data were increasingly obtained by plant enthusiasts, botanical consultants, and various state and federal agency botanists rather than traditional academic botanists with ties to major educational institutions (Ertter 1995; Shevock and Taylor 1987). Initially, the information available to determine which taxa were in fact rare and/ or endemic was fragmentary, with most information restricted to a handful of herbarium specimens (Powell 1974). With efforts directed at rediscovery of old herbarium records, along with systematic and focused fieldwork to document new occurrences, understanding of the distribution of rare and endemic species has greatly improved (Smith et al. 1980; Smith and York 1984; Smith and Berg 1988; Skinner and Pavlik 1994). Floristic inventories are becoming ever more important as a method of documenting the plant diversity of a specific landbase. However, many of the currently available floras and checklists lack citations of representative vouchered specimens to validate each of their entries. Without references to vouchered plant material deposited in major erbaria, these floras and checklists have reduced value because material on which the catalogue of names is based is not available for future study and taxonomic review (Palmer et al. 1995; Ferren et al. 1995). Of course, many floras are based on a review of herbarium records, but again, representative specimens are rarely cited in the publication of floristic studies. Wilken (1995) provides a convincing case for continued floristic studies in California that emphasize comparative analyses based on biogeographical patterns of diversity at both regional and local levels. It may come as a surprise to many not familiar with the California flora that vascular plants are still being discovered and described as new to science for the Golden State. The majority of these newly published species are both endemic and rare.

The period 1968–86 yielded over 220 newly described vascular plant taxa for California; sixty-five of these occur in the Sierra Nevada (Shevock and Taylor 1987). With publication of The Jepson Manual (Hickman 1993), ongoing floristic analysis by Shevock and Taylor (in preparation) will document that since 1986 this trend of discovery and publication of new vascular plant taxa continues. The southern Sierra Nevada in particular, along with other areas of carbonate and serpentinite geology, remains an area of the state worthy of continued floristic study and research (Norris 1987; Shevock 1988). During the past few years several new species have been discovered in the Sierra Nevada. Because many of these new taxa are rare and/or endemic to a single river basin, they are incorporated in this assessment with the specific epithet “sp. nov.,” “ssp. nov.,” or “var. nov.” until the names have been effectively published according to the International Code of Botanical Nomenclature. This assessment was developed to determine the distribution of both endemic and rare plant taxa in the Sierra Nevada, primarily at the river basin level. For the core study area, the Sierra Nevada was divided into twenty-four river basins (figure 24.1) ranging in size from the Feather at 971,611 ha (2,399,878 acres) to the Calaveras at 94,018 ha (231,285 acres). River basin boundaries are useful because they are easy to determine both in the field and on maps, in contrast to political boundaries such as counties, forests, and parks, which have the potential to change through time. Furthermore, river basins provide a biogeographical context in which to evaluate floristic components such as rare and/or endemic species. Size, elevation range, geology and soils, vegetation types, and geographical location of each river basin are factors used to speculate why river basins vary widely in total number of taxa, including rare and endemic species. As a general overview, the northern Sierra is predominantly volcanic in origin, and the central and southern Sierra are both mainly granitic, with several areas of metamorphic and metasedimentary parent materials.

The diversity of habitat types that occur in the Sierra Nevada also explains the great richness of endemic and rare species within this mountain range. The broad plant communities used by Munz and Keck 1959, along with those used in Skinner and Pavlik 1994, provide the basis for recording habitat preferences for rare and/or endemic taxa in this study. Several additional habitat types not based on vegetation were recorded, because many rare taxa seem to be more dependent on them than on the surrounding vegetation type. For example, seventy taxa, or nearly 12% of rare and/or endemic taxa, can be found on rock outcrops. Many endemics and/or rare taxa are located exclusively on a particular rock type, such as carbonate, serpentine, basalt, or granite. Other taxa have distributions that correspond more closely with elevation zones or that span several habitat types. Distribution patterns for rare and/or endemic species differ considerably from river basin to river basin, and the distribution of these elements between habitat types is also varied. There are five dominant habitat types: Jeffrey and ponderosa pine forest types contain 211 taxa, the largest concentration of rare and endemic elements in the Sierra; the second largest, the foothill woodland, contain 139 taxa; subalpine forests contain 124 taxa; meadows have 116 taxa; chaparral, 90 taxa. Of the five habitat types that contain the most rare and endemic taxa, the foothill woodland and chaparral are receiving the greatest increase in impacts and/or fragmentation by urbanization along the western slope of the Sierra Nevada. In chaparral vegetation types, the frequency of fire has been altered to protect other resource values, such as timber and homes. An example of this change in the Sierra Nevada is occurring at the residential development areas of Cameron Park, Pine Hill, and Salmon Falls in El Dorado County. Several rare taxa are restricted or locally endemic to gabbro soils in this area and are impacted by a direct loss of habitat by development. Those taxa that are dependent on fire as part of their life history and ecology may be negatively impacted by long-term changes in the management of chaparral vegetation. The changes may include a shift from fall to spring burning, mechanical treatments, or alteration of the fire frequency.

Habitat or Functional Floristic Guilds

The term “guild” in used in ecology to mean a group of species that use similar resources in a similar way (Root 1967), occur in similar habitat, and respond to processes such as fire or floods in the similarly. Species may be grouped by their edaphic (soil), moisture, or canopy closure requirements, associated vegetation types, or how they obtain “food” (e.g. photosynthesis or saprophytic). For example, a group of plants adapted to riparian forests could be said to comprise a riparian guild. Or a group may be based on plants that occur in sunny openings in forests, or unburned, litter rich, shady forest patches. The groups or guilds for this assessment are in progress but will be generalized as to what can be assessed with existing information at the bio-regional scale. This is likely to include: vegetation type, canopy cover, time since fire (at different severities), and within-stand vegetation heterogeneity. If possible, edaphically defined guilds may also be addressed, but it depends on the resolution and quality of available data. Guilds can vary in space (where they occur) or time (temporal), such as after a fire or flood.

The guilds used in the 2001 Sierra Nevada EIS included the following groups table below. We will be reducing the list by combining groups and perhaps adding others. For many of these we do not have spatial data.

Spatially Defined Guilds.
Meadows and Seeps
Vernally Wet
Riparian Woodland
Riparian Forest
Bogs and Fens
Non-forested Lakes and Streamsides
Rock Outcrops
Ultramafic (serpentine)
Cliff
Edaphic specialists
Temporally Defined Guilds
Interior (Old Growth) Forest
Openings (Small Gaps) in Forests
Post-fire Openings
General Openings

Edaphic habitats

Edaphic habitats are those where the ecology of a site is driven principally by soil conditions. These include areas underlain by ultramafic rock (“serpentine”), calcareous rock (limestone and marble), and areas of thin or nonexistent soil, such as rock outcrops and cliffs. Soils developed on ultramafic rocks are characterized by very low levels of most important plant macronutrients, including calcium, potassium, and nitrogen, and high levels of potentially toxic heavy metals such as chromium, nickel and cobalt. These habitats often develop open forest or shrublands characterized by stunted, slow-growing vegetation. The challenging conditions on serpentine soils result in the occurrence of many rare and endemic plant species. Soils developed on calcareous rocks are enriched in calcium, and can provide excellent growing soils under high precipitation regimes but are often rocky and thin in semiarid landscapes like much of the assessment area. Calcareous soils also support some rare and endemic plant species, mostly in the southern assessment area. Rock outcrops and cliffs may occur on any bedrock type. They present challenging conditions for growth simply due to the general absence of soil. These habitats are common throughout the assessment area.

All of these edaphic habitats are generally unproductive and tend to support vegetation dominated by scattered herbaceous plants and shrubs, or open forests where conditions allow. The lack of dense vegetation and slow succession on these habitats also results in less frequent fire and there is evidence that the occurrence of some rare and endemic species is more closely tied to escape from frequent fire than escape from biological competition.

In the northern assessment area, many areas of ultramafic soil are found in and around populated areas at lower elevations and urban and suburban expansion is impacting increasing areas of habitat. Because of slow growth, cutting of trees on ultramafic soils has much longer-lasting ecosystem effects than on more productive soils.

Examples of edaphic habitats from the eastside on the Inyo National Forest include the following types: • Carbonate (C) – includes those species restricted to carbonate substrates; Alkali Flat (AF) – includes species found in highly alkaline soils.

Meadows and seeps

Meadows occur where herbaceous plant species dominate the site. Meadows can be divided into two broad hydrologic types: groundwater fed meadows and dry meadows. Groundwater-fed meadows occur where there is a shallow water table, and finely textured soils accumulate (Ratliffe 1985). Dry meadows occur where the water table is deep but there is sufficient soil moisture at some point in the year, usually spring or early summer, to allow herbaceous species to establish and become dominant. Woody species may occur on these meadow types but they are not the dominant vegetative cover. Both groundwater-fed and dry Meadows occur in a number of different settings and are fed by a variety of water sources (Weixelman et al. 2011). Meadows occur in depressions where water collects (depressional meadows), adjacent to flowing streams (riparian meadows), adjacent to lakes or reservoirs (lacustrine fringe), near springs and seeps (discharge slope), or meadows may occur in valley bottoms with no flowing stream and only subsurface water feeding the meadow (subsurface meadows).

Plant species that dominate groundwater-fed meadows are typically hydric species adapted to a shallow water table (Fites-Kaufmann et al. 2005). These include sedges (Carex spp.), rushes (Juncus spp.), and grasses and forbs adapted to shallow water tables. Dry meadows contain herbaceous species adapted to drier soils and are typically less productive. Plant species that occur in meadows and seeps can be classified into groups that respond similarly to management (Weixelman and Gross, unpublished). These are termed plant functional groups. For example, plants that tolerate disturbance, e.g. trampling or grazing, are termed ruderal species (Winward 2000). These are species that are adapted to disturbance and tend to increase with disturbance in a meadow. Examples include dandelion (Taraxacum officinale), western aster (Aster occidentalis), and western yarrow (Achillea millefolium). Some species do not tend to increase with disturbance but instead decrease with disturbance. These are called late successional plant species or competitors. Examples include Nebraska sedge (Carex nebrascensis), and beaked sedge (Carex utriculata). Of importance to managers is knowing the proportions of these plant groupings, or plant guilds, in a meadow. For example, these plant groupings can be used to assess the ecological integrity, or ecological health, of the meadow in terms of species composition and the level of disturbance that is occurring. These species groupings, as used in this example, can be used in both groundwater-fed meadows and dry meadows to assess the condition of the meadow. Other metrics such as species richness and diversity are generally controlled by both the type of meadow and the level of disturbance on a site (Safford et al. 2001).

Other indicators of ecological integrity in a meadow include the amount of stream incision that may have occurred (Simon and Rinaldi 2006). Stream incision, or downcutting of the stream channel affects the timing and duration of flooding the meadow receives, as well as the level of the groundwater in many meadow systems, which in turn affects the ability of the meadow to support hydric vegetation and desired habitat for a multitude of meadow fauna (Loheide et al. 2009). An additional indicator of meadow ecological integrity is the amount of encroachment by upland plant species including coniferous species. Encroachment by these types of species can indicate drying of the meadow due either to management actions and/or climatic influences. Ecological assessment of meadows often takes into account factors related to both hydrology and vegetation of a meadow area (Stillwater Sciences 2012, Gross et al., unpublished).

References
  • Fites-Kaufman, J, P. Rundel, N. Stephenson, D. A. Weixelman. 2007. Montane and Subalpine Vegetation of the Sierra Nevada and Cascade Ranges. Pp 456-501. In: M.G. Barbour,T. Keeler-Wolk, and A.A. Schoenherr, eds. Terrestrial Vegetation of California, 3rd ed. Ed: University of California Press, Berkeley, CA, 712pp.
  • Gross, S.E., Weixelman, D.A., and H. Safford. Using an ecological framework to track meadow health and function in the Lake Tahoe Basin. Unpublished manuscript, to be submitted, Spring, 2013.
  • Loheide, S.P., Deitchman, R.S., Cooper, D.J., Wolf, E.C., Hammersmark, C.T., and Lundquist, J.D. (2009) A framework for understanding the hydroecology of impacted wet meadows in the Sierra Nevada and Cascade Ranges, California, USA.
  • Ratliff, R. D. 1985. Meadows in the Sierra Nevada of California: state of knowledge. Gen. Tech. Rep. PSW-84. Pacific Southwest Forest and Range Experiment Station, USDA Forest Service, Albany, California.
  • Safford, H.D., M. Rejma´nek, and E. Hadac. 2001. Species pools and the ‘‘hump-back’’ model of plant species diversity: an empirical analysis at a relevant spatial scale. OIKOS 95: pp. 282–290.
  • Simon, A., Rinaldi M., 2006. Disturbance, stream incision, and channel evolution: The roles of excess transport capacity and boundary materials in controlling channel response. Geomorphology 79 (2006) 361-383.
  • Stillwater Sciences. 2012. A guide for restoring functionality to mountain meadows of the Sierra Nevada. Prepared by Stillwater Sciences, Berkeley, California for American Rivers, Nevada City, California.
  • Weixelman, D. A., B. Hill, D.J. Cooper, E.L. Berlow, J. H. Viers, S.E. Purdy, A.G. Merrill, and S.E. Gross. 2011. A Field Key to Meadow Hydrogeomorphic Types for the Sierra Nevada and Southern Cascade Ranges in California. Gen. Tech. Rep. R5-TP-034. Vallejo, CA. U.S. Department of Agriculture, Forest Service, Pacific Southwest Region, 34 pp.
  • Weixelman, D.A, and Gross, S.E. 2013. Plant functional groups in relation to disturbance and hydrology in mountain meadows, Sierra Nevada and Southern Cascade Ranges, CA. Unpublished manuscript, to be submitted Spring, 2013.
  • Winward, A.H. 2000. Monitoring the Vegetation Resources in Riparian Areas. USDA Forest Service, Rocky Mountain Research Station. RMRS-GTR-47.
  • Yarnell, S.M., J.H Viers, and J.F.Mount. 2010. Ecology and management of the spring snowmelt recession. Bioscience: Vol. 60 No. 2. Pp 114-127.


Riparian Forest and Woodland Guild


Importance of Guild

Riparian forests represent a keystone community type, playing a more significant ecological role than their proportional area in the landscape would suggest (Gregory et al. 1991; Malanson 1993). Currently, the amount of land in the assessment area classified as riparian forest habitat type is only 58 km2, with an additional 119 km2 of riparian scrub (Kattelmann & Embury 1996). Yet riparian ecosystems in the Sierra Nevada, as elsewhere, provide many important ecological services, including: streambank stabilization, sediment retention, water quality improvement, hydraulic process moderation, and wildlife species habitat provisioning (Patten 1998). Key hydrologic functions provided by riparian vegetation include: improving water quality by trapping and filtering sediment, nutrients, and pollutants; reducing flood damage and enhancing ground-water recharge by slowing water velocity and increasing river surface area; and maintaining an elevated water table by preventing channelization (Patten 1998). Today, Sierra Nevada runoff provides almost 65% of water for agricultural and other human uses in California (Timmer 2003). Riparian communities contain more plant and animal species than any other California community type (Schoenherr 1992) and about one fifth of terrestrial vertebrate species in the Sierra Nevada depend on riparian habitat (Kattelmann & Embury 1996). Riparian zones also play an important role as ecological corridors (Naiman & Decamps 1997) and recreational sites.

Guild Description

Species of the riparian forest and woodland guild generally share the following ecological traits: broad-leaved; winter-deciduous; fast-growing; short-lived; requiring high soil-moisture; tolerant of flooding and low oxygen root environments; and able to produce sprouts, suckers, and new root systems (Kattelman & Embury 1996). Riparian tree species can generally be divided into two main categories: pioneer species and secondary successional species (Vaghti & Greco 2007). Pioneers, which include species of Salix, Platanus, Populus, and Alnus, often release their water/wind born seeds in late spring, when flooding creates moist, available substrate (Vaghti & Greco 2007). They rely on flooding to create habitat and low summer flows to promote seedling survival (Vaghti & Greco 2007). They are fast growing and produce debris like leaf litter that aids in soil development. Later seral species, like those of Acer, Fraxinus, and Quercus then grow up through the accumulated litter in areas where less frequent flooding occurs (Vaghti & Greco 2007).

In general, as slope increases, as substrate coarsens, and/or as flooding frequency increases, riparian communities tend to simplify (Harris 1989; Harris 1999). Depth to water table is a key determinant of vegetation patterns within riparian areas (Loheide & Gorelick 2007; Elmore et al. 2003), with obligate wetland plants (e.g. Salix gooddingii) giving way to facultative wetland plants (e.g. Populus fremontii) and facultative riparian conifers (e.g. some Pinus spp. and Caocedrus decurrens), and finally to upland species (e.g. Abies concolor ) and some oak (Quercus spp) in the outer floodplain locations as depth to groundwater increases (Stromberg et al. 1996; Harris 1989). Particular dominant vegetation is often associated with specific substrates or locations within the channel profile (e.g. Willows (Salix spp.) are often associated with sand and cobble substrates and alders (Alnus spp.) are often found immediately adjacent to channels; Harris 1989).

Disturbance is particularly important to riparian ecosystems as many riparian plants are disturbance adapted (Kobziar & McBride 2006; Naiman & Decamps 1997; Naiman et al. 1998; Potter 2005; Vaghti & Greco 2007). Plant distribution and composition depends on both fluvial disturbance (e.g. debris flow, floods, scouring) and nonfluvial disturbance from adjacent upland ecosystems (e.g. fire, wind, disease, avalanche, herbivory, pests, etc.; Gregory et al. 1991; Naiman et al. 1998). Riparian conditions (e.g. flooding, depth to water-table) are often the dominant force driving riparian stand composition in the Sierra Nevada, with fire playing a significant, though less prominent role (Russell & McBride 2001; Stromberg & Patten 1996). Under natural flow regimes in the Sierra Nevada, variation in flood frequencies, levels, and durations creates a diversity of age and structural conditions within riparian communities. These processes often result in high levels of patchiness through both space and time, with average riparian plant associations existing in patches smaller than 0.1 hectares or 0.25 acres (Kattelmann & Embury 1996; Kobziar & McBride 2006; Potter 2005).

Current Condition & Management Considerations

Despite evidence than many riparian zones (particularly bordering steeper, narrower, or more incised streams) historically exhibited fire return intervals (FRI) similar to those of surrounding upland areas, management plans in the assessment area often exclude any sort of disturbance-based management in riparian zones (Van de Water & North 2010). Mechanical thinning, as well as prescribed burning and managed wildfire, are frequently prohibited in the riparian corridor due to concern for both water quality and sensitive riparian ecosystems (Kobziar & McBride 2006). This policy may have both positive and negative impacts on the riparian guilds, including reduced fire-related erosion and stream warming, but also greater fuel accumulation, fire risk, and evapotranspirative water demand. All measures of fire risk in riparian zones (e.g. fuel loads, stand density, predicted post-fire tree mortality, etc.) are currently significantly higher than in reconstructed historic conditions (Van de Water & North 2011). One study showed that prescribed fire had no lasting negative effects in riparian areas of a northern Sierra Nevada stream (Beche et al. 2005), and scientists are beginning to recommend considering vegetation/fuel treatment in riparian areas as part of landscape restoration strategies (Van der Water & North 2011), taking into account characteristics of riparian systems that influence the natural fire regime (e.g width, presence of pine species, latitude, longitude; etc.).

In addition to fire suppression, water development has significantly impacted the riparian guild in the assessment area. Generally, water development in California has reduced overall flow, reduced seasonality of flow, and shifted flow peak timing of waterways, reducing spring flood pulses and augmenting summer flow (Vaghti & Greco 2007). Water diversion in some areas has been estimated to mimic the effects of the most severe droughts of the previous 2,000 years (Benson et al. 2002). The reduced seasonality of flow, resulting in a lack of episodic disturbance and increased summer water levels, has led to decreased recruitment of pioneer species like Populus through the western United States (Vaghti & Greco 2007). Decreased recruitment is compounded by decreased growth and survival, due to lower overall water flow averages (Stromberg & Patten 1990). Management to mimic natural flow regimes should be emphasized.

Riparian zones are among those areas within the assessment area most heavily affected by non-native species invasions (Schwartz et al. 1996). Salt cedars (Tamarix chinesis, T. ramosissima, T. parviflora) have notably invaded the southern and eastern portions of the Sierra Nevada, and are better adapted to survive water stress and drought conditions than genera like Populus and Salix (Smith et al. 1991; Shafroth et al. 2000; Alstad et al. 2008). Salt Cedar invasion may also increase flammability of riparian systems, interacting with the increase in fire risk through fire suppression to create highly volatile conditions (Alstad et al. 2008). Ailanthus (tree of heaven), introduced in to the US in 1784 from Asia, has impacted mainly the foothill regions of the Sierra Nevada, below elevations of 1,000 meters (3,280 ft) (Schwartz et al. 1996). Russian olive, introduced during the Euro-colonial period, is known to decrease site suitability for cottonwood species, thus further impacting riparian zone composition (Schwartz et al. 1996). Other non-native species that readily colonize riparian ecosystems of the Sierra Nevada include giant reed (Arundo donax), perennial pepperweed (Lepidium latifolium), Himalayan blackberry (Rubus discolor), and purple loosestrife (Lythrum salicaria) (D’ Antonio et al. 2004). Interrelated to the effects of invasive species, are the impacts of grazing, which have been particularly strong in the riparian zones. In addition to affecting overall vegetation density, grazing also directly affects riparian plant species in idiosyncratic ways. Some willow species, such as Lemmon’s willow (Salix lemmoni) and Shining willow (S. lucida ssp. lasiandra) are heavily browsed, while other, less palatable species like Sierra willow (S. orestera) are rarely browsed (Potter 2005). Thus, both grazing and species invasions have likely impacted relative species dominances and community composition within the riparian guild.

Trends

As of the mid 1990s, about one quarter of wildlife species that depend on riparian habitat were considered at risk of extinction (Graber 1996; Kattelmann & Embury 1996), and half of the 32 amphibian species and almost half of the 40 fish species/subspecies found in the Sierra Nevada were endgangered, threatened, or of special concern (Jennings & Hayes 1994; Moyle et al. 1996). Additionally, 85% of Sierra Nevada watersheds are characterized by poor to fair aquatic biotic communities (Moyle & Randall 1996). Today, riparian zones are at greater risk of fragmentation, non-native species invasion, and high severity fire, than historically. An analysis of aerial photographs of about 1/5 of the Sierra Nevada Watersheds showed that 121 of 130 watersheds have clear gaps in the riparian corridor – largely from road/railroad crossings, timber harvest, private lot clearing, livestock grazing, and dam/diversion dewatering (Kondolf et al. 1996). Riparian zones are also among those areas of the Sierra Nevada most impacted by non-native invasive species (Schwartz et al 1996), and altered riparian systems may be especially vulnerable (Parks et al. 2005). Van de Water and North (2011) found that current riparian forests are likely more fire prone than reconstructed historic riparian forests, including greater duff and total fuel loads, predicted surface and crown flame lengths, probability of torching, and predicted post-fire tree mortality.

Anticipated impacts of climate change to riparian ecosystems in the Sierra Nevada include more frequent and severe flash flooding events, earlier peak flows, greater streambed incision, increased evapotranspiration rates, contraction of riparian communities, increased invasions by non-native species, increased stream temperatures, and lower groundwater recharge (Southern Sierra Partnership 2010). Projected future conditions will thus likely exacerbate the current trends of increased fragmentation, invasion, and fire risk, as well as decreased average and minimum streamflows. Finally, as the human population of California continues to grow, so too will demand for water, leading to greater diversion and de-watering within the Sierra Nevada riparian systems (Elmore et al. 2003). The synergistic impacts of declining water table depth, due to human demand[, and increased climate variability, due to climate change, are likely to facilitate further invasion by non-native species (Elmore et al. 2003).

References

  • Alstad, K. P., S. C. Hart, J. L. Horton, and T. E. Kolb. 2008. Application of tree-ring isotopic analyses to reconstruct historical water use of riparian trees. Ecological Applications 18:421-437.
  • Bêche, L. A., S. L. Stephens, and V. H. Resh. 2005. Effects of prescribed fire on a Sierra Nevada (California, USA) stream and its riparian zone. Forest Ecology and Management 218:37-59.
  • Benson, L., M. Kashgarian, R. Rye, S. Lund, F. Paillet, J. Smoot, C. Kester, S. Mensing, D. Meko, and S. Lindstrom. 2002. Holocene multidecadal and multicentennial droughts affecting Northern California and Nevada. Quaternary Science Reviews 21: 659-682.
  • D’Antonio, C.; Berlow, E.L.; Haubensak, K.L. 2004. Invasive exotic plant species in Sierra Nevada ecosystems. In: Murphy, D.D.; Stine, P.A., eds. Proceedings of the Sierra Nevada Science Symposium; 2002 October 7-10, Kings Beach, CA. General Technical Report PSW-GTR-193. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 175-184.
  • Elmore, A.J., J.F. Mustard, and S.J. Manning. 2003. Regional patterns of plant community response to changes in water: Owens Valley, California. Ecological Applications 13: 443 – 460.
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Post-fire Openings

High severity fire can create openings in forests characterized by varying densities of dead trees (snags). Openings vary greatly in size, depending on fire conditions, weather, topography and forest type. Shrub and herbaceous species diversity is often high in these sites, as in any forest gap, but comparatively few species in the Sierra Nevada are true “fire followers” (fire followers require fire heat, ash, or smoke to germinate). Most species responding positively to fire-created gaps are opportunistic species benefitting from increased availability of sunlight, mineral soil, and resources due to removal of the tree canopy and competitors. Examples of true fire followers in the assessment area include conifer species with serotinous cones, such as Pinus attenuata and the cypress species, and shrub species from the genera Ceanothus and Arctostaphylos. Some of the few herbaceous fire followers include species from the genera Emmenanthe, Dicentra, and Nama. Fire suppression reduced the frequency of this habitat across the assessment area, but successional trends toward denser forests dominated by fire intolerant trees led to greater size of postfire openings when they occurred. Over the last 25 years, increases in fire occurrence and severity have resulted in an increasing trend in the number and size of postfire openings.

Other habitats that support uncommon or rare understory plant species, particularly on the eastside or at high elevations in the alpine and subalpine ecological zones include the following.

  • Open (O) – includes those species found in very open, sparsely vegetated and in some cases barren communities, e.g., pumice flats, sandy meadow margins, talus, rock fields, etc.
  • Alkali Flat (AF) – includes species found in highly alkaline soils.
  • Shrub (S) – includes species found in Great Basin and montane shrub communities, e.g., sagebrush scrub, montane chaparral, bitterbrush, etc.
  • Desert shrub (DS) – includes the lower elevation desert shrub types, e.g., Mojave mixed desert scrub, saltbush, spiny menodora, shadscale, etc.
  • Pinyon woodland (PW) – includes species found in pinyon or pinyon-juniper woodlands.
  • Alpine (ALP) – includes those species found in alpine habitats, e.g., alpine fell-field communities.

Ch1_Terrestrial_SpecialHabitats.jpg
Ch1_Terrestrial_Aspen.jpg

Aspen depicted in this map is an overrepresentation because in its current, highly fragmented condition, it does not show up unless the locations are magnified, like we have done here. Other special habitats, including Bristlecone pine and giant sequoia illustrate the very limited distribution of these unique and well-loved plant communities. Recently burned patches can attract and support many species, in particular birds. The pattern of recently burned areas is vastly different in montane forests than the evidence from NRV indicates (Safford 2013). The patches are larger across continuous areas but vastly decreased as smaller patches, particularly within-stand scale (North 2012).

This uniformity, along with absence of low to moderate intensity fire, has resulted in a vast reduction in fine-scale forest complexity. Small, sunny openings, favored by some plants, are relatively rare. Areas cleared of dense, deep leaf and needle litter are uncommon, impeding germination of some types of plants. Shrubs and herbs that need sun or fire to flower or develop vigorous foliage are scraggly or decadent. As a result, understory animals, such as rodents and songbirds, that depend on these plants are decreased. The trend for homogenization and lack of fire to invigorate understory plants will continue. On the other hand, the trend is for larger patches of uniform, early aged, or early seral vegetation to develop after fire. This can be good for the plants and animals in these habitats. The patches are often very large; however, compared to historic patterns, and are widely distributed, limiting movement of species between them, or “connectivity”.

Ch1_Terrestrial_Early_Seral_Veg.jpg


Groups of Bird Species Associated with Specific Habitats

Many other habitat types warrant regular monitoring and assessment to ensure that important ecological functions and processes are continuing to be resilient to stresses and perturbations both natural and anthropogenic. Again, avian monitoring data are uniquely efficient and appropriate measures for addressing the conditions of habitat types such as:

shrub and chaparral

(http://data.prbo.org/apps/snamin/uploads/Managing%20Shrub%20Habitat%20for%20Birds%20in%20the%20Sierra%20Nevada.pdf);

aspen forest

(http://data.prbo.org/apps/snamin/uploads/images/aspen/Managing%20Aspen%20Habitat%20for%20Birds%20in%20the%20Sierra%20Nevada.pdf);

mixed conifer-hardwood

(http://data.prbo.org/apps/snamin/uploads/Managing%20Mixed%20Conifer%20Hardwood%20Habitat%20for%20Birds%20in%20the%20Sierra%20Nevada.pdf);

burned forest

(http://data.prbo.org/apps/snamin/uploads/images/fire/Managing%20Post%20Fire%20Habitat%20for%20Birds%20in%20the%20Sierra%20Nevada.pdf);

meadows

(http://data.prbo.org/apps/snamin/uploads/images/meadows/Managing%20Meadow%20Habitat%20for%20Birds%20in%20the%20Sierra%20Nevada.pdf).

Location data for more than 100 avian species on USFS lands are available via the Sierra Nevada Avian Monitoring Information Network (http://data.prbo.org/apps/snamin/) which include ongoing avian monitoring efforts and are updated yearly with new occurrence data. Species of special conservation concern were assessed through a collaborative effort by California Department of Fish and Game (CDFG) and PRBO Conservation Science (http://data.prbo.org/apps/bssc/) to inform biologists, land managers, and decision makers of the need to protect at-risk birds and of the best methods to do so.


Complex Early Seral Habitat

The Sierra Nevada ecoregion is widely regarded as having one of the most diverse temperate coniferous forest ecosystems in the world and its conservation status is considered critically endangered due to extensive forest fragmentation and other land-use stressors (Ricketts et al. 1999). An extraordinary assortment of vegetation types and diverse forest successional (seral) stages from young to old-growth forests adds to the region’s importance. While much of the conservation attention in the Sierra Nevada has focused on iconic conifers like giant sequoia (Sequoiadendron giganteum) and old-growth forests generally, complex early seral forests (CESFs) created by stand-replacing fire, or lower intensity disturbances such as fires, insects, and windthrow, are underappreciated for their unique biodiversity (Swanson et al. 2010), and, as such, CESFs are not even included as a habitat type in any current vegetation mapping used by the Forest Service (e.g., California Wildlife Habitat Relations). Complex early seral forests occupy sites with forest potential that occur in time and space between a stand-replacement disturbance and re-establishment of a closed-forest canopy. Today's young forests, if resulting from purposeful regeneration harvest or from fire salvage harvest, lack some of the features and characteristics of unmanaged forests.

CESFs are rich in post-disturbance legacies (e.g., large live and dead trees, downed logs), and post-fire vegetation (e.g., native fire-following shrubs, flowers, natural conifer regeneration), that provide important habitat for countless species and differ from those created by logging (e.g., salvage or pre-fire thinning) that are deficient in biological legacies and many other key ecological attributes (Table 1; see also Table 1 in Swanson et al. 2010, Table 1 in Donato et al. 2012). Thus, to distinguish early seral forests from logged early seral, the term “complex” is used in association with early seral produced by natural disturbances. However, as the characteristics that might define 'complex' are not universally defined, purposeful management actions may be able to retain and/or create functionally equivalent environments.

Ch1_Terrestrial_Early_Seral_Veg.jpg

In the Sierra Nevada, CESFs provide habitat for dependent species like Black-backed Woodpeckers and are most often generated by mixed-severity fires, which include patches of varying sizes burned at high severity. There are no inventories of CESFs in the Sierra Nevada. Importantly, there does not currently exist an inventory of CESFs nor have historic and baseline CESF levels been determined in order to assess representation of CESFs in the planning areas.


Photo: Burned forest, Tioga Pass, northern Sierra www-rcf.usc.edu

Table 1. Differences between early seral systems produced by natural disturbance processes vs. logging. For natural disturbances, assume that a disturbance originates from within a late-successional forest as legacies are carried over to disturbed sites during succession. For logged sites, assume site preparation includes conifer plantings but no herbicides. While the illustration below displays woody material, likely collected on a landing, rapid recolonization of plants soon occurs.
Attribute
Regeneration Harvest or Postfire Logged
image 3.jpg
Moonlight immediately postfire logging 2009
Natural Disturbance
image 4.jpg
Star fire 2008 unmanaged (subsequent to one or more growing seasons)
Large trees [snags and some live trees]/downed logs
lower than undistrurbed, but the degee is dependent on harvest design
abundant and widely distributed
Post-fire shrubs and natural conifer regeneration
dense conifer plantings followed by sparse vegetation as conifer crowns close (usually within 15-20 years depending on site productivity)
varied and rich flora
Species composition
highly variable, dependent on planting design and vegetation managment strategies used, deer initially abundant then excluded as conifer crowns close
varied and rich flora, rich invertebrates and birds, abundant deer
Structural complexity
reduced by the removal of dead wood, degree dependent on salvage design
highly complex; many biological legacies
Soils and below-ground processes
variable levels of compaction, dependent on several factors, reduced mycorrhizae, largely dependent on the length of time between tree death and recolonization
complex and functional below ground mats
Genetic diversity
low due to emphasis on commercial species and nursery genomes
complex and varied
Ecosystem processes (predation, pollination)
moderate initially then sparse as conifer crowns close; limited food web dynamics
rich pollinators and complex food web dynamics
Susceptibility to invasives
moderate to high depending on site preparation, soil disturbances, livestock, road densities (see McGinnis et al. 2010)
low due to resistance by diverse and abundant native species and low soil disturbances
Disturbance frequency
dependent on future wildfire effects (unknown timeframe) and/or management decisions (approximately 100 years to several centuries are possible)
varied and complex
Landscape heterogeneity
dependent on design used during reforestation
high; shifting mosaics and disturbance dynamics
Ecological integrity
ldependent on scale and management actions
high
Resilience/resistance to climate change
inherently dependent on the genetic variability of the seedlots used in reforestation; opportunities are significant to attempt to adjust for locally anticipated climate envelopes
varied and complex genomes allow for resilience and resistance to climate change

Fire and CESFs

CESFs in mixed conifer forests are found along the west slopes of the Sierra Nevada at mid elevations (760-1400 m, northern) ascending to higher elevations south (915-3050 m; Chang 1996) and along upper elevations on the east slopes of the range. In drier low-elevation forests, fires are reoccurring and are often low severity, but can have significant mixed-severity effects; mid to upper elevations and mesic forests are characterized by mixed-severity fires that include patches of high severity, and have variable return intervals. (Leiberg 1902, USDA 1910-1912, Show and Kotok 1924, Show and Kotok 1925, Stephenson et al. 1991, Beaty and Taylor 2001, Bekker and Taylor 2001, Nagel and Taylor 2005, Bekker and Taylor 2010, Collins and Stephens 2010, Miller et al. 2012, North 2013).

image 12.jpgimage 13.jpg
Star Fire of 2001, Northern Sierra unmanaged with forbs on left (2008) and natural conifer
re-establishment on right (2012)

Fire is nature’s architect in the Sierra Nevada and it varies widely depending on topography, vegetation, fuels, and climatic factors. Fire regimes most likely to generate CESFs include variable interval and intensity fires in upper montane red fir (Abies magnifica); very-long-interval, stand-replacement fires in mixed-conifer and white fir (Abies concolor) forests; and variable (both short and long interval) stand-replacement fires in Douglas-fir and lodgepole pine forests (Leiberg 1902, USDA 1910-1912, Show and Kotok 1924, Show and Kotok 1925, Stephenson et al. 1991, Chang 1996, Beaty and Taylor 2001, Bekker and Taylor 2001, Nagel and Taylor 2005, Bekker and Taylor 2010, Collins and Stephens 2010,
Miller et al. 2012). Fire, therefore, is an important pathway to CESFs, whether partially, as in low to moderate fire intensities that create fine-scaled heterogeneity (e.g., canopy gaps where succession is reset) at the stand level, or mixed intensity that creates coarse-grained heterogeneity at the landscape level.
image 14.jpgimage 15.jpgimage 16.jpg

Storrie fire of 2000, S. Cascades, unmanaged with snags and forbs on left (2007); Postfire logged portions of Freds fire in the Eldorado National Forest showing lack of nitrogen-fixing
shrubs (center) and presence of Klamath weed (Hypericum perfoliatum) and many readily ignitable, invasive grasses (right) (2011).

Although views on fire are gradually shifting, the Forest Service has attempted to mimic the lower severities of mixed-severity fires mechanically or via prescribed fire in mid- to upper-elevation mixed conifer forests. Management aimed at stopping large fires that historically and currently produce landscape heterogeneity continues through fire suppression as well as widespread mechanical fuel treatments designed to lower the susceptibility of forest ecosystems to high-severity burns. Although there are desired social and cultural benefits in reducing risks to crown-fire damage in iconic forests such as giant sequoia and in the wildland-urban interface, this has come with consequences to CESFs as sequoia, for example, depend in part on mixed- to high-severity fires. In addition, traditional views on high-severity fire as a destructive force that is increasing in frequency and extent have been challenged due to concerns about the importance of post-burned landscapes and data limitations of current fire studies (Brown et al. 1999, Baker and Ehle 2001, Veblen 2003, Baker 2006, Odion and Hanson 2006, Baker et al. 2007, Sherriff and Veblen 2007, Klenner et al. 2008, Odion and Hanson 2008, Baker 2012, Williams and Baker 2012a, Williams and Baker 2012b). Moreover, as described recently in Donato et al. 2012, the "slow, sparse or suppressed tree establishment" associated with CESFs post-fire "may actually accelerate the development of certain forms of spatial complexity that are typically associated only with late-successional forests."

image figure 3.jpg





(Figure 3 in Donato et al. 2012): "Three alternate successional pathways for forest development, showing the relative levels of structural complexity exhibited in each seral stage. In the conventional successional model, both early- and mid-seral conditions are dominated by a relatively even-aged tree cohort, and structural complexity does not arise until the latest stage of development. In the case of analogous precocity, early-successional stands exhibit structural complexity in some ways similar to that in old stands, but canopy closure results in reduced complexity during mid-succession. In the case of homologous precocity, the lack of a tree canopy-closure phase results in a continuity of complexity throughout forest development."






Climate Change And CESF Habitat

Forest fragmentation and climate change have been identified as key issues for forest planning in the Sierra Nevada. Indeed, the climate of the Sierra Nevada is changing and it is unequivocally caused by greenhouse gas emissions from burning of fossil fuels, deforestation and forest degradation, and other factors operating at global and regional scales. In the past century the Sierra Nevada have experienced climate changes (California Energy Commission 2006). Since the 1980s at least, the region has experienced an increase in monthly minimum temperatures of 3° C with effects differing across elevations (Jardine and Long 2013). Annual number of days with below-freezing temperatures in higher elevations is decreasing with more rain and less snowfall mainly in northern latitudes of the ecoregion, while the number of extreme heat days at lower elevations is increasing (Safford et al. 2012, Harpold et al. 2012). Snowmelt occurs 5 to 30 days earlier than decades ago, and peak stream flows have been occurring 5 to 15 days sooner. Some have projected that the onset of fire season could be extended as a result in low- to mid-elevation conifer forests (Safford et al. 2012). Regional climate models project further decreases in mountain snowpack, earlier snowmelt and peak stream flows, and greater drought severity (Overpeck et al. 2012). Such climatic changes are likely to affect the lower elevation ponderosa pine, which is projected to extend upward, and red fir or subalpine projected to lose much of its climate envelope in the coming century. It is unclear how such changes will affect CESFs; however, if fire increases in severity or frequency (Miller et al. 2009 and Miller and Safford 2012—note that these studies excluded severe fire early in their time period of analysis by not using pre-burn vegetation mapping and by omitting some fires), this could provide more opportunities for development of CESFs. This assumes, however, that there is not a proportional increase in post-fire logging, and that fire suppression activities either cannot keep up with the pace of climate-related fire events or prove ineffective due to the increasing influence of climate as a top-down driver of fire behavior. On the other hand, a number of climate models predict decreasing fire activity in these forests—even as temperatures increase—due to increasing precipitation, including summer precipitation and changes in vegetation (McKenzie et al. 2004, Krawchuk et al. 2009).

In addition to climate change, land-use stressors can magnify effects to forest communities and their resistance and resilience to change. For instance, Thorne et al. (2008) documented significant regional changes due to climate and land-use practices resulting in greater levels of disturbance (compared to historical), and substantial (42%) changes in cover types with largest gains in montane hardwood, Douglas-fir, and annual grasslands and biggest losses in low-elevation hardwoods (particularly blue oak, Quercus douglasii), woodland, chaparral, and upper elevation conifers like red fir. Millar (1996) also identified three paramount influences on Sierra Nevada ecosystems: (1) climate change and shifting hydrological patterns; (2) dense forests; and (3) rapidly expanding human populations.

Current Management of CESF Habitat

Post-disturbance management of CESFs has most often included post-disturbance (salvage) logging followed by intense site preparation, including burning of slash piles with associated soil disturbances, reseeding with grasses (often introducing invasive species inadvertently), use of straw-bales and other erosion prevention methods, use of herbicides to reduce shrub competition with conifers, planting with conifer nursery stock, and livestock grazing (Swanson et al. 2010, Long et al. 2013; Table 1). These activities remove or severely degrade CESFs or, at a minimum, can delay or limit the duration of CESFs (Paine et al. 1998, Swanson et al. 2010), contributing to “landscape traps,” whereby entire landscapes are shifted into, and then maintained (trapped) in, a highly altered state as the result of cumulative impacts (Lindenmayer et al. 2011). Thus, given the importance of the Sierra Nevada in general, and the values inherent to CESFs, these forests require proper stewardship, particularly to meet the intent of the new planning rule regarding its emphasis on ecological integrity and to limit cumulative effects of multiple, and often chronic, land-use disturbances in these developing forests.

The new forest planning rule directs the Forest Service to include ecological integrity in forest plan revisions, and, from an ecosystem perspective, managers wanting to implement an ecosystem integrity approach will need to determine historical and current representation of the full range of natural seral stages across the planning area to comply with the forest planning rules emphasis on diversity. Under-representation of any of these stages (from early to mid to late) would reflect shortcomings in ecological integrity approaches, and landscape-scale indices are needed to monitor extent of seral stages and their distributions in forest planning using a combination of baseline (reconstruction) and forecasting approaches (see below). Notably, recent studies (e.g., Fontaine et al. 2009, Burnett et al. 2010, Siegel et al. 2010, Burnett et al. 2011, Siegel et al. 2011, Burnett et al. 2012,
Donato et al. 2012,Siegel et al. 2012a, 2012b) have shown that avian use of post-burn sites is highest if the pre-burn site maintains biological legacies (large trees, snags, down logs) that “lifeboat” important ecosystem functions across seral stages. Thus, from a management standpoint, intense pre- or post-disturbance logging of seral stages can create a long-term successional debt that eliminates legacies essential for maintaining ecological integrity across forest seral stages (DellaSala et al. 2011).

Determining the appropriate representation and distribution of CESFs in a planning area will require “back-casting” designed to reconstruct an historical baseline by combining age-structure reconstructions (e.g., from either FIA plot data or General Land Surveys from the 1800s, see techniques in Baker 2012 and Williams and Baker 2011, Williams and Baker 2012) with fire scar data (although this requires rigorous sampling designs to address variability in tree scaring from fire, and cannot address historic high-severity fire occurrence) to allow reconstruction of historical fire severity. Historical baselines can then be compared to current and future projected conditions under a changing climate in order to determine appropriate levels of CESFs and other seral stages in a planning area. This information is lacking for the Sierra Nevada.

Black-Backed Woodpeckers Exemplify CESFs
image 5.jpg

I believe it would be difficult to find a forest-bird species more restricted to a single vegetation cover type… than the Black-backed Woodpecker is to early post-fire conditions…
Richard Hutto (1995:1050)

No other vertebrate species exemplifies CESF like the Black-backed Woodpecker, a “keystone species” and important primary excavator of nesting holes for itself and other cavity-nesting birds and mammals (Tarbill 2010). It also is one of the most highly selective bird species not only with respect to using burned or otherwise naturally disturbed CESFs, but also targeting specific nesting and foraging snags within a stand – their optimal habitat is dense conifer forest with high basal area of medium and large trees (e.g., mature and old-growth) that has been severely burned, or which has experienced high mortality from beetles, and has been protected from post-disturbance logging (Hutto 2006, 2008; Hanson and North 2008, Tarbill 2010, Siegel et al. 2012). Black-backed Woodpeckers can only effectively use a snag forest for a few years (typically 7 or 8) after it is created, and densities typically decline steeply after about 4 or 5 years following fire (Siegel et al. 2011). Thus, they depend upon the future occurrence of high-intensity natural disturbance to constantly replenish their habitat and are highly sensitive to post-fire logging, which tends to eliminate, or severely degrade, suitable habitat (Hanson and North 2008, Hutto 2008, Siegel et al. 2012 [Fig. 10—near total avoidance of clearcut salvage logged areas in a radiotelemetry study]). Unfortunately, due to lack of habitat protection and fire suppression, Black-backed Woodpeckers have become increasingly rare. For example, these birds in the Sierra Nevada were once described as “numerous” historically but are now considered “rare,” and their optimal habitat there has shrunk to a fraction of historical conditions (Hanson 2012, 2013). Several recent analyses of Black-backed Woodpecker populations in the Sierra Nevada estimate <600 nesting pairs occurring in burned forests, and several hundred pairs or at most several thousand in green forests (Bond et al. 2012; Appendix C Table 7 page 116). The best available science indicates that the overall population in the Sierra Nevada is likely to be below the extinction-risk thresholds of approximately 4,000 individuals (~ equivalent to 2,000 pairs) (Hanson 2013; Traill et al. 2007, 2010). Other research indicates that 7,000 adult individuals are necessary in a population to ensure 99% probability of population persistence over the course of 40 generations—and that the risk of extinction increases dramatically at such threshold population levels if the population is being subjected to “strong deterministic (anthropogenic) factors and habitat destruction” (Reed et al. 2003). Importantly, the remaining pairs have little or no protection on most of the area that they inhabit, and are under mounting pressure from logging practices that prevent high-quality woodpecker habitat from being created on the landscape, or remove it once created.

Historical and current post-fire logging is the greatest threat facing this woodpecker and, more broadly, the burned forest system its presence represents. Moreover, widespread fire suppression, forest restoration thinning, and fire/beetle-prevention thinning projects decrease the potential for new habitat to be created by natural disturbances because those activities are aimed at eliminating mixed- and high-severity fires. The reduction in tree density substantially degrades habitat quality when those thinned stands eventually do burn in a subsequent wildland fire (Hutto 2008). Finally, fire and beetle prevention projects that lower the density of larger trees (which most do) also degrade the older unburned forests used by the Black-backed Woodpecker when burned forest is temporarily unavailable (Siegel et al. 2011).

Post-fire occupancy by Black-backed Woodpeckers also is correlated to fire severity and forest density/maturity, with the woodpeckers strongly selecting areas with the highest densities of medium and large snags (Hanson and North 2008, Tarbill 2010, Siegel et al. 2012).

Given the tight association between these woodpeckers and CESFs, it is reasonable to assume that this species is an indicator (or focal species) of CESFs in the Sierra Nevada. Conifer forest types that are potentially used by Black-backed Woodpeckers in the Sierra Nevada region include mid- and upper-montane conifer forests (Figure 2, panel a). Post-fire habitat since 1984 within these conifer forest types on public lands is scarce (Figure 2, panel b) as it is often logged (private lands were not included since they are usually immediately logged post-fire). Similarly, moderate to high-severity fire habitat, equating to ~ >50% mortality (RdNBR >574—see Hanson et al. 2010) on public lands in the most recent fires for which there are fire severity data (2001-2010, panel c, and the most recent 5 years with fire severity data – panel d) is also rare.

Figure 2. (a) (b) (c) (d)
image 6.jpgimage 7.jpgimage 9.jpgimage 9.jpg

Notably, the new planning rule provides guidance to forest managers to use focal species as a means for maintaining species diversity and wildlife population viability. In particular, the planning rule refers managers to focal species approaches that were recommended by the Committee of Scientists (1999) to provide insights into the integrity of the larger ecosystem to which a particular species belongs. CESFs are a neglected and rare seral stage that provides habitat for dependent species like Black-backed Woodpeckers on the decline because burned habitat is most often logged. Given this woodpecker already is an indicator species of burned forests in the Sierra Nevada, and given its rarity and the threats to its persistence (Hanson et al. 2012, 2013), forest managers should designate this woodpecker as a Species of Conservation Concern and step up monitoring and protection of its CESF in the Sierra Nevada.

CESFs and California Spotted Owls
image 10.jpg

The California Spotted Owl is designated as a management indicator species for all national forests in the Sierra Nevada. Available evidence and knowledge of spotted owl ecology across all three subspecies (Mexican, California, Northern; Bond et al. 2002, Jenness et al. 2004, Clark 2007, Roberts 2008, Bond et al. 2009, Roberts et al. 2011, Lee et al. 2012) show that owls tolerate some degree of moderate to high-severity fire within territories. For example, mixed-severity fire (with an average of 32% high severity) does not reduce California spotted owl occupancy (Lee et al. 2012), and the owl is known to occur and reproduce in territories burned at all fire severities in this region and preferentially selected high-severity fire areas for foraging (Bond et al. 2009). Post-fire logging, however, may precipitate territory extinction (Clark 2007). Consequently, managing CESFs for high levels of ecological integrity would provide important habitat for California Spotted Owls, a species that the Forest Service currently assumes is threatened by high-severity fire.

Photo of California spotted owl on snag in the
McNally Fire area, California

Managing CESFs to Achieve Ecological Integrity

The forest planning rule directs the Forest Service to take an all lands approach to forest management, given that factors influencing a planning area occur at large spatial scales and the emergence of climate change requires coordinated actions across jurisdictions. For instance, Region 5 has been emphasizing management and restoration to achieve ecosystem resilience to climate, and this approach can be integrated with the planning rule’s emphasis on ecological integrity. Because CESFs currently represent a neglected seral stage, managers should account for the following regarding CESFs:
image 17.jpg1 - “Rehabilitation” is not necessary in complex early seral forests. Fire acts as a natural restorative agent for these forests by resetting the successional clock and providing habitat for disturbance-dependent species like Black-backed Woodpeckers. Just because they lack live trees initially and are populated by dead trees, does not mean CESFs require site rehabilitation or are “unhealthy” forests. (See, e.g., Hutto 1995, Shatford et al. 2007, Haire and McGarigal 2008, Hanson and North 2008, Hutto 2008, Donato et al. 2009, Saab et al. 2009, Burnett et al. 2010, Haire and McGarigal 2010, Swanson et al. 2010, Burnett et al. 2011, Collins et al. 2011 [pages 15-23; tables 5 and 6], Donato et al. 2012, Seavy et al. 2012, Buchalski et al. 2013).
2 – Postfire restoration activities may be necessary in early seral forests previously degraded by logging, grazing, and other human stressors. Areas of high ecological integrity (e.g., unmanaged CESFs) can serve as a baseline or reference condition from which to restore degraded areas (e.g., burned plantations), and this should be followed with effectiveness monitoring in an adaptive management sense. Moreover, forest managers can extend the early seral stage in areas that have previously been converted to plantations through creation of canopy gaps (e.g., through snag creation and felling trees to create downed log habitat) and variable-spaced thinning of small trees, providing a mixture of habitat for some closed canopy species and early seral dependents. As trees mature, snags can be created and felled to help meet coarse woody debris requirements for wildlife and increase structural complexity so that subsequent natural fire disturbance can produce a more natural post-disturbance landscape in the future.
3 – Land-use stressors can compromise the integrity of CESFs. Pre-fire “restoration” harvests outside the wildlands-urban interface, as well as post-fire logging, reseeding, conifer planting, erosion prevention, road building, and use of herbicides or insecticides, can severely impact CESFs. (See, e.g., Hutto 1995, 1998, Paine et al. 1998, Hanson and North 2008, Saab et al. 2009, Swanson et al. 2010, Lindenmayer et al. 2011, Burnett et al. 2011, Seavy et al. 2012, Siegel et al. 2012). Livestock grazing can also affect the ecological integrity of CESFs. Further, because prevention of high-severity fire (via mechanical means or fire suppression) is the status quo approach in the Sierra Nevada (Sierra Framework 2004), the importance of high-severity fire patches must be recognized and accounted for in order to conserve the wildlife and habitat associated with CESFs.

Burned forest, Lake Tahoe area
4 –Historical, current, and projected future distributions and spatio-temporal extent of CESFs is lacking. Because data is partly lacking regarding the historical and current status of CESFs, it is necessary to collect more data so that meaningful assessments can be made regarding CESFs. Back-casting and forecasting techniques can be used to make assessments and determine appropriate representation goals in order to maintain ecological integrity and habitat diversity implicit in the new forest planning rule. (See, e.g., Williams and Baker 2011). It is also important to differentiate between the trends and status associated with CESFs – for example, even if there exists a trend towards increasing high-severity fire, the status of CESFs may nonetheless have a different trajectory for a number of reasons, such as a) the burned area may not be complex in the first place (due to its pre-fire status), or b) the burned area’s complexity may be negated by salvage logging or by reforestation efforts. Moreover, the status of CESFs is important separate from trend because even if trend shows an increase in CESF, there may still be a severe deficit of CESF compared to past levels.
5 – Rare species associated with CESFs, especially the Black-backed Woodpecker, should be designated as “Species of Conservation Concern.” By continuing and expanding upon current monitoring efforts, and in partnership with the US Fish & Wildlife Service and species experts, the population viability and habitat needs of rare and important CESF species can be maintained.
6 – Old forest structures as well as dense, old forests should be maintained in order to protect CESF habitat. Large old forest structures take decades to centuries to develop and forest management has otherwise created a successional debt from intensive high-grade logging. Moreover, data indicate that some rare CESF species, such as the Black-backed Woodpecker, rely not merely upon higher-severity fire areas but upon dense, mature/old forests that have recently experienced such fire (Hutto 1995, 2006, 2008, Hanson and North 2008, Tarbill 2010, Siegel et al. 2012). Maintenance of dense, old forests is therefore important in order to provide high-quality habitat when such areas experience mixed-severity fire, or snag pulses from beetles or competition among conifers (Bond et al. 2012).

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Connectivity of Selected Ecosystem Types


The ability for species to move throughout a landscape or bio-region, is important for overall population viability and integrity. One key reason is that when local populations become isolated, they become genetically isolated. Then they tend to lose the genetic variability that allows them to respond successfully to changes, such as climate change or new diseases or major changes in habitat. This is suspected for the fisher, since the population in the southern Sierra Nevada is isolated from those to the north and west. Another species that is wide-ranging that is often used to represent the integrity of sagebrush ecosystems is the sage grouse (http://static.sagegrouseinitiative.com/sites/default/files/grsg_rangewide_breeding_density4.pdf). The connectivity of sagegrouse habitat, sagebrush ecosystems, is being widely affected by cheatgrass invasion and subsequent changes in fire regimes and further sage brush changes.

Old forest associated species were identified as an important indicators of ecological integrity because of the long history of reductions in old forest structure following settlement and more recently (Franklin and Fites-Kaufman 1996; USDA 2001 vol. 2, part 3.2 p. 148). Further, species of concern in the Sierra Nevada that preferentially utilize old forests tend to be associated with larger areas with at least some old forest elements throughout (Zielinski 2013, PSW Draft Science Assessment; Keanne 2013, PSW Draft Science Assessment).


Connectivity - Open Space

Connectedness of un-urbanized land (open space), species habitat, and ecological processes are important to biodiversity and ecological integrity (Lindenmayer and Fisher 2006). Connectivity is particularly important to consider at the bio-regional scale (Chapter 1, WIKI). Movement across all lands and different forest administrative units is difficult to consider one small area at a time.

Density and distribution of open space provides a broad picture of areas serving as habitat and movement corridors for individual species. Land where the focus is on resource management and conservation including county, state, and federal governments, land trusts, and conservation easements on private land are more likely to provide “open space” and connectivity for species and habitats, particularly species at risk. Urban areas do not.

In the map below, we assessed “open space” by creating a picture of the density of urbanized areas and private land where management was uncertain into the future. On this map, these areas are depicted as broad zones w with different concentrations, or percent of area, of open spaces and other lands. Broad categories of <5%, 5 to 25%, 25 to 50%, 50 to 75%, and more than 75% private land were mapped. The assessment area is subdivided into six different geographic areas that depict differences in climate and dominant vegetation. On the western half, to the west of the mountain crest, are four geographic areas. The northern geographic area includes the southern Cascade Mountains and areas to the west, encompassing the western one-third of the Lassen National Forest and Plumas National Forests, and Lassen National Park. The central geographic area includes the western half of the Tahoe National Forest and the entire Eldorado National Forest and adjacent private lands. The Stanislaus National Forest, Yosemite National Park and foothill areas to the east make up the central south geographic area. The south geographic area is comprised of the Sierra and Sequoia National Forests, Sequoia & Kings Canyon National Park, and private foothill lands to the west. To the east of the crest, there are two geographic areas. South of Lake Tahoe is the southeastern geographic area, encompassing the Inyo National Forest, the westernmost portion of the Toiyabe National Forest, and intervening Bureau of Land Management lands, and private lands. The entire Modoc plateau including the Modoc National Forest, and extensive Bureau of Land Management and private lands, the eastern two-thirds of the Lassen National Forest, and the eastern half of the Plumas and Tahoe National Forests comprise the northeastern geographic area.

Ch1_Terrestrial_OpenSpace.jpg

The foothills are the most urbanized and have the least potential for open space, most with >75% private land. Beyond the foothills, open space is more continuous in the southern and central portions, with <5% private land, than the northern portions of the bio-region. To the west of Lake Tahoe and north, there are alternating large areas with >75% private with other areas of <25% private land. Large areas on the Eldorado and Tahoe National forests have extensive “checkerboard” lands, with 50% private land, a legacy from railroad land grants. Not all private land is urbanized, and many areas provide for habitat and movement of at least some species.

Some of the foothill private lands are used for ranching, above the foothills for forest management. These private lands can provide benefits of “working” landscapes with connectivity for a wide variety of species, if not all. Recent reintroduction of fisher onto the private timber lands of Sierra Pacific Industry is an example where focused attention on biodiversity and commercial timber objectives can provide for connectivity. Previously, fisher was absent from its former range in the northern Sierra Nevada and southern Cascades, but in the reintroduction area they are expanding and successfully breeding. Time will tell the final outcome.

Intermixed, private land and the roads that go with and between them have impacted species, such as deer, that move seasonally across the same large areas every year. Roads provide important services to society; however, their presence can also negatively influence the movement of species, hydrology, geomorphology, and ecosystem processes on National Forest System lands. There are numerous articles in the peer reviewed literature describing the impacts of roads on the landscape (Chapter 11, WIKI). A significant number of deer are killed along roads, (Romin et al. 1996) and others limited in movement or foraging habitat by fences, houses, or pets. Areas that have a lower proportion of open space have greater and sometimes severe connectivity issues for migrating species like deer.

The ability for species to move throughout a landscape is important for overall population viability and integrity. When local populations become isolated, they also become genetically isolated. They then tend to lose the genetic variability that lets them respond successfully to changes such as a new disease, a change in habitat, or climate change. Connectivity depends on habitat needs and life history of each individual species. It is not practical to look at connectivity for all species, and so for this assessment, we focused on three aspects of connectivity related to habitat types or groups of species of concern: sagebrush (sage grouse), old forest (California spotted owl, and fisher), early seral vegetation (songbirds and some woodpeckers). In particular, the role of fire patterns in affecting connectivity of these habitats and the species associated with them.


Connectivity of Sagebrush Ecosystems


Sage grouse lives in sagebrush habitat, with riparian areas in proximity. Locations in California are restricted to several in the southeast, on the Inyo National Forest and adjacent BLM lands, and in the far northeast, on the Modoc Plateau. Expansion of the non-native, invasive cheatgrass is reducing and fragmenting habitat. Although fire is a natural component of the sagebrush ecosystem, more recently, it can also result in more rapid invasion of cheatgrass.


Ch1_Terrestrial_SageGrouse.jpg

Section in progress—for a map of sage grouse locations and report by BLM please see attached link
http://static.sagegrouseinitiative.com/sites/default/files/grsg_rangewide_breeding_density4.pdf


Early Forest Connectivity

Some species that rely on complex early-seral forest habitat, such as the black-backed woodpecker, may not be able to detect new habitat beyond a certain distance (see, e.g., Hoyt and Hannon 2002). Consequently, like the temporal aspect of post-disturbance habitat, the spatial extent and connectivity of post-disturbance habitat on the landscape is likewise critical to wildlife.

The pattern of recently burned areas is vastly different in montane forests than the evidence from NRV indicates (Safford 2013). The patches are larger across continuous areas but vastly decreased as smaller patches, particularly within-stand scale (North 2012).

This uniformity, along with absence of low to moderate intensity fire, has resulted in a vast reduction in fine-scale forest complexity. Small, sunny openings, favored by some plants, are relatively rare. Areas cleared of dense, deep leaf and needle litter are uncommon, impeding germination of some types of plants. Shrubs and herbs that need sun or fire to flower or develop vigorous foliage are scraggly or decadent. As a result, understory animals, such as rodents and songbirds, that depend on these plants are decreased. The trend for homogenization and lack of fire to invigorate understory plants will continue. On the other hand, the trend is for larger patches of uniform, early aged, or early seral vegetation to develop after fire. This can be good for the plants and animals in these habitats. The patches are often very large; however, compared to historic patterns, and are widely distributed, limiting movement of species between them, or “connectivity”.

Ch1_Terrestrial_PctEarlySeral.jpg


Old Forest Connectivity


We are using three approaches to look at connectivity of old forests or habitat that contains old forest element. First is the distribution of old forest characteristics itself. Second is the distribution of species and suitable habitat for wide-ranging, top trophic level species that are tied closely to at least some elements of old forest. The species we have chosen are the California spotted owl, fisher, and pine marten. Habitat suitablility models and characterizations for these species continue to be a focus of on-going research (http://www.fs.fed.us/psw/publications/reports/psw_sciencesynthesis2013/index.shtml). Some of the key habitat elements identified in ground-based research plots, including large trees and snags, have not been available in remote sensing based maps used to map landscape patterns of habitat suitability (i.e. California Wildlife Habitat Relations Types). This makes it difficult to assess connectivity of the habitat alone without considering the species that uses it. There is new remote sensing data from LIDAR that shows more promise but is only available in limited areas and has not been fully tested in this research application yet.

How does the following discussion of CASPO and fisher differ from what will be in Ch. 5? What habitat info is most pertinent to the Ch. 1 terrestrial ecosystems discussion, and how is it being used here? Focus on connectivity?? Should Ch. 1 be primarily the coarse scale discussion, with fine scale items/spp primarily addressed in Ch. 5, i.e. those elements/spp that are not adequately managed using the coarse filter info?


California Spotted Owl


The Science Synthesis completed by Dr. John Keane of the US Forest Service, Pacific Southwest Research Station, provides a comprehensive review of scientific literature on ecological condition of the California Spotted Owl (Keane 2013). This section is a brief summary of that scientific synthesis. In addition, there is a map of owl locations from the US Forest Service monitoring database. This section should be considered skeletal at this time, pending more time to incorporate the Science Synthesis, the final copy of which was available this week.

The California Spotted Owl is forest carnivore that occurs throughout the Sierra Nevada, on the west slopes in the southern Sierra Nevada and in the central and northern subregions on the western slopes and in some areas transitional to the eastside, drier landscapes north of the Eldorado National Forest. Mixed conifer, white fir, Douglas-fir, yellow pine are the most common CWHR habitat types the owl is found in. But it is also found in red fir at higher elevations, and hardwood, riparian woodlands at lower elevations, particularly in the Southern Sierra Nevada. Research on habitat relations has been conducted primarily at three different scales (Keane 2013).
Insert picture of California Spotted Owl

At the finest scale, nest or roost trees and patches, the owl preferentially selects large, an often the largest, and oldest trees, in a patch (Keane 2013). High canopy closure (local canopy density, as opposed to canopy cover, which is an average density across a stand: sensu North and others 2009, 2012) is associated with the nest or roost trees in these patches or clumps. Owls have poor temperature or thermoregulation, and are thought to prefer the canopy cover to maintain body temperature.

At the intermediate scale, the “core habitat” where the owls are most frequently located using radio-telemetry studies, owls are also associated with patches of high canopy closure and cover (Keane 2013). Average stand diameter tends to be at the high end (>24” dbh) but many stands with medium diameter (12-24” dbh) are also common, since in much of the Sierra Nevada large trees are found scattered or in clumps in these stands as well (Franklin and Fites-Kaufman 1996). Average stand diameter is often not a good reflection of the presence or abundance of large trees used by owls, but is what remote sensing vegetation data that is available characterizes (USDA 2001: p 129-137). On-going research with LIDAR imagry (laser) that can be used to detect presence and spatial patterns of large trees will greatly improve the ability to characterize owl habitat structure at the core area scale. At this time, it is unknown the density or distribution of large trees owls are associated with beyond those utilized by nest and roost trees.

At the homerange, encompassing one to several thousand acres, the size varying with habitat type and prey density, the owls are associated with more varied habitat mosaics (Keane 2013). This is likely because at this scale habitat use is for foraging and the small mammals they prey on use a variety of habitats and habitat elements. For example, wood rats are often found in small patches of shrubs. Deer mice are found in a variety of habitats and use large down wood at least some of the time. Flying squirrels use trees spaced closely (for flying distance) as well as large trees or snags for denning.
A spatial analysis of what habitat is present within nested circles around nest locations is being conducted using the existing vegetation maps shown previously with CWHR types. This is in progress. It can be difficult to interpret what this information represents for spotted owl occurrence and reproduction, since there is some research in this area but generalities are difficult at this time given the variability of habitat conditions they use at these scales, and the lack of mapping of key habitat elements such as large trees.

The California spotted owl is well distributed, depicted by occurrence monitoring by the US Forest Service. Two important cautions when viewing this map need to be considered. First, in order to see the owl locations in a map of this scale, the size of the dot is larger than an actual homerange of an owl, so they look much denser than they are on the ground. Second, in this type of course-filter monitoring, the locations represent individual sitings; there may be multiple sitings in different years of the same individual, figure below.

Although the owl is well distributed, there are some areas of concern that were identified by Verner et al. (1992) that are still of concern today. The bulk of these are in the northern Sierra Nevada where mixed ownership and heavy timber harvest occurred in the 1970’s and 1980’s took place. Today, on privately owned timber lands throughout the west slope of the Sierra Nevada, widespread clearcutting is occurring at a scale approaching 2 million acres. These are short rotation tree cropping systems managed with agricultural chemicals. Additional areas of concern have arisen more recently where numerous, very large fires have resulted in large expanses of non-forested or young forest areas (i.e. portions of the Stanislaus National Forest).

Gradual, but steady population declines over the past 20 years have been observed (Keane 2013). Population trends have been developed using metapopulation analysis of four demography study areas distributed throughout the Sierra Nevada. The next one is planned for late summer. It is unknown whether the declining trend will persist or not. It is unknown what historic distributions or populations were.

There have been few studies on the effect of fires and vegetation management on California Spotted Owl survival and reproduction (Keane 2013). At this time, the effect seems to depend upon the severity and extent of the fire. Low severity fires have been found to have little effect but extensive high severity fires have a great effect (Keane 2013). Most fires are a mosaic of different severities (mixed severity) and in these situations, less is known. Bond et al. 2009, in a radiotelemetry study, found that California spotted owls preferentially selected high-severity fire areas (which had not been salvage logged) for foraging. In addition, Lee et al. 2012 found that mixed-severity wildland fire, averaging 32% high-severity fire effects, did not decrease California spotted owl territory occupancy, but post-fire salvage logging appeared to adversely affect occupancy. Effects on nesting habitat are more straightforward to track than effects on foraging and prey base. Fire effects can include rejuvenation of understory vegetation and increase heterogeneity. Similarly, mechanical treatment can have varying effects depending upon the intensity, extent and changes to different habitat elements.

Distribution of California spotted owl occurances from the US Forest Service monitoring database. [Comment: Need range of dates that these occurence observations encompass]. Two important cautions when viewing this map need to be considered. First, in order to see the owl locations in a map of this scale, the size of the dot is larger than an actual homerange of an owl, so they look much denser than they are on the ground. Second, in this type of course-filter monitoring, the locations represent individual sitings; there may be multiple sitings in different years of the same individual


Ch1_Terrestrial_SPO_sm.jpg
Ch1_Terrestrial_SPO_NRF_sm.jpg
Add explanation of figure above

Trends in Owl Habitat in Relation to Fire

Owls and their associated habitat have developed over time in forested ecosystems characterized by recurrent fire, the foothill, montane, and upper montane forests and woodlands of the Sierra Nevada, southern California, and the southern Cascades. As fire patterns have changed dramatically since European settlement and suppression, vegetation has become denser, more uniform, and fire effects have trended toward larger areas of high severity (van Wagtendonk and Fites-Kaufman 2006). Fires and their effects can affect owl habitat and owls in both negative and positive ways (Bond et al. 2002 and 2009; Lee et al. 2012; Roberts and North 2012; Keane 2013). In addition, salvage logging that occurs post-fire can impact owls (Clark 2007) -- thus, when characterizing fires in regard to owls, it is essential to take into account whether the area was salvage logged (e.g., Moonlight Fire).

Given the uncertainty with what levels of fire severity or what proportion of habitat in different levels of fire severity are important to owl survival and reproduction, we conducted exploratory analysis on a range of values of fire severity and proportion of owl habitat affected. Using the US Forest Service Region 5 Fire Severity Monitoring data (Miller and Safford 2008, Miller et al. 2009) we mapped owl protected activity centers that has the following combinations of fire severity, defined by proportion of tree basal area affected, and area burned. Fires from 1984 through 2010 were included. Although the PAC layer is dated 2001, owls have a high fidelity for nest trees and it is a reasonable assumption that the 2001 PACs are representative of at least many of the owl sites that would have been present in 1984. It could also be an underestimate of owls that were affected between 1984 and 2001, since surveys were less common before then.

Source Information
of Protected Activity Centers
Fire Severity Level
(% Tree Basal Area
affected)
% of Protected Activity
Area Burned at Severity level
2001
>50
>50
Current
>50
>50
2001
>75
>50
Current
>75
>50

Both 2001 and current PAC layers were used because of two reasons. There have been changing land management direction on whether PACs are redrawn or removed. In the 2001 Forest Plan revisions, the direction was “Maintain PACs regardless of California spotted owl occupancy status, unless habitat is rendered unsuitable by a catastrophic stand-replacing event and surveys conducted to protocol confirm non-occupancy”. In the 2004 Supplemental Decision, the direction was modified to “PACs are maintained regardless of California spotted owl occupancy status. However, after a stand-replacement event, evaluate habitat conditions within a 1.5 mile radius around the activity center to identify opportunities for re-mapping the PAC. If there is insufficient suitable habitat for designating a PAC within the 1.5-mile radius, the PAC must be removed from the network.” This makes it difficult to track cumulative effects of fire over time on owl PACs.

These maps show differences between the 2001 and current base as well as some bioregional patterns. Each red dot depicts a PAC that met the criteria for the basal area severity criteria (either 50% or 75%).

Current PACs, 75% Basal Area Severity
2001 PACs, 75% Basal Area Severity
Ch1_Terrestrial_SPO_Current75_sm.jpg
Ch1_Terrestrial_SPO_2001_75_sm.jpg


Current PACs, 50% Basal Area Severity
2001 PACs, 50% Basal Area Severity
Ch1_Terrestrial_SPO_Current50_sm.jpg
Ch1_Terrestrial_SPO_2001_50_sm.jpg

First it is clearly evident that using the 2001 owl habitat base, there are more owl locations affected by fire. We have not sorted out yet, how many owl sites were subsequently removed due to loss of habitat from fire or lack of occupancy from owls with later surveys. The change in direction makes this a complicated question to sort out easily.

Second, there several spatial patterns evident. One is that there have been owl sites affected by high severity fire across more than 50% of the PAC across the entire range of its distribution in the bioregion. Second, there have been the most PAC’s affected in the north and south, particularly the north. The eastern portion of the Sequoia and Plumas have been most affected, in particular the Plumas. This has two potential implications. First, that the drier forests are more susceptible. Second, that single large fires can have big effects to multiple owls in a given area. Two examples are the McNalley fire on the Sequoia National Forest and the other is the Moonlight fire on the Plumas National Forest. The results from the Chips fire that occurred last summer on the Plumas are not tallied yet, but preliminary field observations are that multiple owl sites have also been affected by high severity fire (Keane, personal communication 2/2013). Given the continued trends in fire (area of high severity fire) in the primary owl habitat of mixed conifer, will likely make the number of PACs affected by high severity fire increase over time, and perhaps accelerate. When assessing the impacts of fire on PACs, it is also important to examine the salvage logging that occurred post-fire. For example, salvage logging associated with the Moonlight Fire occurred adjacent to PACs.

Another implication of the trends observed are that the owls that are on the eastern edges of its distribution are particularly at risk and have been impacted. This may be significant in that there may be genetic variation in those owls that is important, particularly in light of climate change and trends toward drier more open forests. This possible genetic variation was noted by Dr. Jared Verner, retired owl scientist, on numerous occasions.

Ch1_Terrestrial_SPO_NRF_AC_sm.jpg

References

  • Miller, J. D., & Safford, H. D. (2008). Sierra Nevada Fire Severity Monitoring 1984-2004. USDA Forest Service, Pacific Southwest Region.)
  • Miller, J. D., Safford, H. D., Crimmins, M., & Thode, A. E. (2009). Quantitative evidence for increasing forest fire severity in the Sierra Nevada and southern Cascade Mountains, California and Nevada, USA. Ecosystems, 12(1), 16-32.
  • Bond, M. L., Lee, D. E., Siegel, R. B., & Ward Jr, J. P. (2009). Habitat use and selection by California spotted owls in a postfire landscape. The Journal of Wildlife Management, 73(7), 1116-1124.
  • Bond, M. L., Gutierrez, R. J., Franklin, A. B., LaHaye, W. S., May, C. A., & Seamans, M. E. (2002). Short-term effects of wildfires on spotted owl survival, site fidelity, mate fidelity, and reproductive success. Wildlife Society Bulletin, 1022-1028.
  • Roberts, S.
  • Lee, D.E., M.L. Bond, and R.B. Siegel. 2012. Dynamics of breeding-season site occupancy of the California spotted owl in burned forests. The Condor 114: 792-802.


Goshawk


Goshawk is another potential focal species that occurs across broad areas, like the spotted owl, fisher, and pine marten, but occurs across a different array of habitats. It occurs in more open habitats on the western slopes and in eastside pine forests, and stands of aspen that the owls do not. Similarly, to the California spotted owl, the continuity of its distribution has also been impacted recently by several large wildfires, particularly in the northern Sierra Nevada and southern Cascades on the Plumas and Lassen national forests and vicinities. The map below, illustrates the location of known goshawk sites compared to ecological fire resilience.

Ch1_Terrestrial_Goshawk_FireRes_sm.jpg


Fisher

The Science Synthesis completed by Dr. Bill Zielinski of the US Forest Service, Pacific Southwest Research Station, provides a comprehensive review of scientific literature on ecological condition of the Fisher (Martes pennanti) (Zielinski 2013). At this time, we are in the process of incorporating additional information from this synthesis. There is also a large body of work underway by the Conservation Biology Institute, under the direction of Dr. Wayne Spencer, on modeling habitat relations at den sites, connectivity of habitat and risks to fire. This information will be incorporated in the trend section in the next few months.

Background

Fishers are carnivores and a large member of the weasel family (Mustelidae) that inhabit conifer, mixed-conifer, and hardwood tree habitats interspersed with forest openings (Zielinski 2013). Fishers require large, old trees, snags, or down logs with small cavities for denning and resting. Denning and resting sites are in localized areas of high canopy cover, but may be surrounded by or interspersed with areas of lower canopy cover. They prey on small mammals in the forest understory or in adjacent openings and typically includes squirrels, mice, voles and deer carrion (Grenfell and Fasenfest 1979; Zielinski 2013). Fishers are long-lived, have low reproductive rates, large home ranges (for carnivores of their size) and exist in low densities throughout their range (Powell 1993; Zielinski 2013).

Chap1_Terr_05.jpg

Average fisher home range sizes in the Southern Sierra Nevada of California.
MEAN MALEHome Range (acres)
MEAN FEMALEHome Range (acres)
Source
SequoiaSequoiaSequoia NF MeanSierraSierra
9,855a7,409d8,63215,3855,421
1,644a1,304d1,4743,5342,945
Zielinski et al. (1997)Zielinski et al. (2004b)Arithmetic MeanThompson et al. (2009)bMazzoni (2002)c
Sierra NF Mean
10,403
3,240
Arithmetic Mean
a Mean of two home range estimating techniques: 95% minimum convex polygon, and adaptive kernel. b Fixed kernel estimates based on 8 male and 17 female territories. Male territories include breeding season movements and may therefore overestimate actual territory size.c 95% Minimum convex polygon estimate d 100% MCP

Fisher Movements

Fishers may be active day or night, but peaks occur at sunrise and sunset (Powell 1993; Zielinski 2013). Assuming two activity periods per day, Powell (1993) estimated fishers may move up to 3.1 miles/day.

In 2003, Weir summarized information about fisher dispersal movements and concluded that they were capable of long distance movements, and that neither major rivers nor other topographic features appear to pose impenetrable barriers (Zielinski 2013). Recent anecdotal evidence shows that rivers may serve as filters, however (Purcell, pers. comm.; in Zielinski 2013). Other considerations such as availability of suitable habitat and prey, avoidance of mortality factors like predators, and the presence of conspecifics (which seems to serve as an attractant), may interact to influence dispersal (Weir 2003; Zielinski 2013). In southern Oregon, juvenile female fishers dispersed from 0 to 10.6 miles, with a mean of 3.7 miles, while males in the same area ranged from 4.4 to 34.2 miles, with a mean of 18.0 miles (Aubry and Raley 2006; Zielinski 2013).

The West Coast Distinct Population Segment (DPS), mapped as an area from northern British Columbia south to the southern end of the Sierra Nevada mountains, is currently a Candidate for listing under the Endangered Species Act (Zielinski 2013). Within this area, there are native populations in British Columbia, far southern Oregon, and California. Reintroduced fisher populations now occur in the Olympic Peninsula of Washington, the Crater Lake National Park vicinity in the southern Oregon Cascades and on Sierra Pacific Industries land in the northern Sierra Nevada, adjacent to the Lassen and Plumas National Forests.

Current Condition and Trends

Fisher distribution in California consists of two native populations, a northern California/southern Oregon population that is distributed over 10 million acres, and a smaller southern Sierra Nevada population occurring over approximately. 2.6 million acres, figure below (Zielinski 2013). These two populations are separated by approximately 240 miles. A recent genetic analysis established that this range contraction, isolation and population decline occurred during the end of the Pleistocene or Holocene epochs and may have been reinforced by mega-droughts in the 9th and 13th centuries AD, pre-dating the European settlement of California (Tucker et al. 2012; Zielinski 2013).

Fisher observation data from the USFS database. Note that dot sizes are much larger than the actual locations, in order to depict them at this scale of map.

Ch1_Terrestrial_Fisher_Obs_sm.jpg



The estimates of fisher population numbers in California are fewer than 500 animals in the southern Sierra Nevada, and from 1,000-4,000 in northern California (CDFG 2010). In the southern Sierra Nevada, preliminary estimates of the USFS long-term monitoring effort suggest that the population has remained stable since 2002-03 (Zielinski 2013). However, it is important to distinguish that the word “stable” here is relative: the population has not significantly declined from baseline monitoring numbers that already indicate the population is threatened with extinction.

Naïve occupancy rates, or the proportion of primary sample units detecting fisher across the entire fisher monitoring area (USDA Forest Service 2006, Truex et al. 2009).
Year
Fisher Detection Proportion
2002
0.268
2003
0.234
2004
0.241
2005
0.252
2006
0.277
2007
0.267
2008
0.238

Spatially explicit, empirical models were employed to create maps of the distribution of fisher populations and habitat in the Sierra Nevada and Cascade mountain ranges (Spencer and Rustigian-Romsos 2012). The general result of the modeling indicates that potential habitat tends to be more fragmented in the northern portion of the interior mountains as compared to southern Sierra Nevada (Ibid).

Uncharacteristically severe wildfire, fire and fuels vegetation management that excessively reduces late seral forest acreages and/or fails to retain adequate representations of late seral habitat elements, rodenticide, disease, and roadkill seem to pose the greatest threat to fisher persistence in the southern Sierra Nevada (Zielinski 2013). Other potential threats identified (predation, climate change, poaching/incidental capture, recreation, and urban development) are considered secondary as our understanding of their possible implications or significance would be more speculative (CDFG 2010).

Current Distribution Relative to Historic

In 1937, Grinnell et al. characterized the range of fishers in California as the northern Coast Range, Klamath Mountains, southern Cascades, and the entire western slope of the Sierra Nevada. Recent genetic analyses, however, shed further light on this. It now appears that a significant but non-quantifiable fisher range contraction, isolation and population decline occurred between the northern California and southern Sierra Nevada populations during the end of the Pleistocene or Holocene epochs which may have been reinforced by mega-droughts in the 9th and 13th centuries AD (Knaus et al. 2011, Tucker et al. 2012; Zielinski 2013). This range contraction pre-dates the European settlement of California. Current sub-population genetic structuring in the southern Sierra Nevada indicates a smaller secondary contraction may have occurred that might be attributable, at least in part, to historic logging practices and other human influences (Tucker et al. 2012; Zielinski 2013).

Historic Logging Practices impact on Fisher Populations

The 250 mile gap in the California fisher populations can be traced to the historic harvesting that originated in the Lake Tahoe Basin and extended westward to the Sierra Nevada of eastern California. All timber resources were manufactured to support the Tahoe Basin mining industry including homes and city buildings. As timber resources were logged out in the Tahoe Basin and the south shore of the Lake going last in the late 1880's, the harvesting pressure moved to areas just west of the Basin in California and then north and south along the Sierra Nevada. By the late 1890's large areas of eastern California had been logged and by 1900, it was reported that the original forests had been cut back from Lake Tahoe some 10 to 15 miles. It was described as "denudation of nearly the entire original forest" (History of Tahoe National Forest: 1840-1940).

Current fisher distribution in California consists of two native populations, a northern California/southern Oregon population that is distributed over approximately 10 million acres, and a smaller southern Sierra Nevada population occurring over approximately 2.6 million acres. These two populations are separated by approximately 250 miles (Zielinski-Science Synthesis 2013).

Population Status

Based on habitat and population monitoring, the size of the southern Sierra Nevada population is estimated at between 125 and 250 adults (Spencer et al. 2011). Monitoring has demonstrated that this population has not declined since 2002 (Zielinski et al., 2012). Populations may have saturated most available habitat on the Sequoia and Sierra National Forests.

There are an estimated 1,000-4,000 adult fishers in the existing northern California population (CDFG 2010). No comprehensive northern California regional monitoring is being conducted.

Based upon a personal communication with Aaron Facka (February 14, 2013), a total of 40 fishers (24 females and 16 males) from the northern California population were translocated onto private timberlands in the northern Sierra Nevada (Butte and Tehama Counties) between 2009 and 2011. As of February 2013, 11 of the original 40 animals are known to have died. A minimum of 34 kits have been born, and the population has approximately 78 percent average annual survival. This survival rate is similar to rates at other study sites in California. Depending upon the estimator and method used, this population is now estimated to have a minimum of at least 40 fishers.

Habitat Status

Generally, habitat is restricted to the western slope of the Sierra Nevada in an elevation band of between 3,500 and 7,000 feet. The status and reproduction of the northern Sierra Nevada reintroduced population would seem to be a preliminary indication that suitable habitat is available, but unoccupied. This zone supports a large number of illegal marijuana plantations and some of the areas at high risk and hazard for wildfire.

Due to the departure from historic fire return intervals in the southern Sierra Nevada followed by large wildfires, there may be less habitat now than prior to European settlement. An opposing theory suggests that the lack of fire has created dense younger forests that provide thermal conditions more favorable to fishers in this hot, dry environment. The only reliable empirical data we have is habitat occupancy and modeling based on demonstrated habitat use. Changes in these metrics should be carefully noted.

Low fisher habitat quality and distribution on the Stanislaus National Forest (Spencer et al. 2008) poses a potential barrier to northward expansion of the southern Sierra Nevada population. Other factors that may also be influencing this lack of expansion are mortality rates from predation and roadkill with secondary effects of anti-coagulant rodenticide poisoning.

Trends Under Current Management

Population and Habitat

In Naney et al. 2012, habitat loss to uncharacteristically severe wildfire was the single most important threat for the southern Sierra Nevada population. It is important to keep in mind, however, that no published studies yet exist that examine how fisher respond to actual fires. The studies that do exist are modeling studies that examine the relative risks to Pacific fishers of mechanical thinning versus wildland fire and base their assessments on the assumption of 90% to 100% tree mortality from fire, while actual mortality rates are far lower. (Odion and Hanson 2006, Odion and Hanson 2008, Collins et al. 2009, Collins and Stephens 2010.)

The second tier included mortality from forest roads, fire suppression activities, vegetation management in the form of fuels reduction and timber production activities (including over- and under-story reduction, decreases in structural elements and vegetative diversity), fragmentation, climate change and forest insect/disease outbreaks. The current trajectory of increasing fire risk and hazard, as well as larger more intense fires will affect fisher habitat via fragmentation (decreasing connectivity), and reduction in overall quality and quantity. This may reasonably be expected to decrease population size (via lower reproduction, recruitment and increased mortality) as well as decrease habitat quality, quantity and connectivity with largely the same effects as above plus decreased fitness and survivorship.

In contrast, the northern Sierra Nevada greatest threats were habitat losses due to reductions in overstory and structural elements, habitat fragmentation and uncharacteristically severe wildfire (Naney et al. 2012). Secondarily, the same panel of experts specified mortality from highways and forest roads, human-related lethal events and activities, urbanization, recreation, reduction of understory and vegetative diversity, climate change and forest insect/disease outbreaks as lesser threats for northern Sierra Nevada. Trajectories are projected to be largely similar to those in the southern Sierra Nevada, but perhaps manifesting at a slower pace due to the larger population size and area of occupancy.

Since the West Coast-Wide fisher assessment (Lofroth et al. 2010, Naney et al. 2012), a new highly-pervasive threat has become evident. California accounts for 70 percent of illegal marijuana production nationwide (Gabriel 2013). Anticoagulant rodenticides applied to remove rodents in illegal marijuana plantations bioaccumulate in the tissues of carnivores, and often interact synergistically with other chemicals such as organo-phosphates. This has resulted in both primary and secondary poisoning effects to fishers, creating potential sink habitats (Gabriel 2013). Examples of secondary effects include reductions in fitness and increased susceptibility to mortality factors such as disease and predation.

Level of Certainty

There has been little disagreement among forest carnivore experts as to the level, immediacy and potential effects of the threats noted above.

Trends in Fisher and Fire Resilience

The restricted distribution of the fisher make it vulnerable to the effects of



Sierra Marten


Current Distribution relative to Historic

Historically, the marten was reported to occur throughout the upper montane regions of the Cascades and Sierra Nevada, but survey results indicate that populations in the southern Cascades and northern Sierra Nevada region are now reduced in distribution and fragmented (Zielinski et al. 2005; Zielinski 2013).

Population and Habitat Status

Available habitat for martens in the southern Cascades and northern Sierra Nevada is isolated and has been reduced in area since the early 1900s (Kirk and Zielinski 2009; Zielinski 2013). Remaining marten populations are associated with sites with the largest amount of reproductive habitat (dense, old forest), the greatest number of nearby habitat patches, and nearby reserved land (land protected from timber harvest (Zielinski 2013).

Evidence from surveys in the central and southern Sierra Nevada (Kucera et al. 1995, Zielinski et al. 2005) suggests that the marten population is well distributed.

Trends Under Current Management

Population

Timber harvest is regarded as one of the primary causes of reduction in marten populations in the western United States (Buskirk and Ruggiero 1994). If the bulk of anticipated thinning is planned considering marten needs for large trees, coarse woody debris and dense overstory (>69%; Ellis 1998) canopy and it occurs from below, population decreases from this threat can be minimized. Unless overly dense forest conditions are treated, habitat will continue to be lost to wildfire. Loss of habitat from any cause results in lowered marten population density.

Habitat

Forest thinning for any reason poses the greatest direct threat to marten habitat, with thinning from below having the least impact (Zielinski 2013). Habitat loss due to wildfire is also a great threat. Since the marten elevational distribution of ~4,500 to 10,500 ft. with much in the red fir zone is higher than that of fishers, there may be less thinning to reduce fuels and fire hazard.

Level of Certainty

It is difficult to assess trade-offs between the threat of habitat loss due to vegetation management vs. wildfire with any certainty. Both are likely to result in downward pressures on marten populations and habitat in the most immediate future, while resulting in gains over the long term.


Landscape Mosaics of Old Forests


There are few sources of geographic information on the spatial distribution of old forests, and in particular the locations and densities of key old forest elements of large trees, large snags, and large logs. This is largely due to the fact that only recently have remote sensing data, such as LIDAR, has been available to map large trees. But it is still cost prohibitive for large areas. Consequently, the large, landscape mosaic maps of old forests developed for SNEP using expert knowledge in 1996 is displayed below. There were some updates for fires up to 2000. The second source of information was from on-going modeling of quality and suitable habitat for fisher and marten by the Conservation Biology Institute. This work is in progress, but the authors have graciously given us permission to display here.

Old forest ("LSOG") map from Sierra Nevada Ecosystem Project (Franklin and Fites-Kaufman, 1996. These are "series normalized" ranks, ranging from 0 (none) to 5 (high concentration). The criteria for what is old forest in the series normalized varies with the dominant forest type. For example, in montane westside forests, trees >40" dbh are considered. In subalpine forests, trees >18" or sometimes smaller, with sparse canopy would be considered high quality. This map does not incorporate fires since 1996, any tree mortality or harvests. This map only represents forests on public lands (all ownerships), not private.


Ch1_Terrestrial_LSOG_sm.jpg

Trends in fire across the bioregion have implications for connectivity of wide ranging species of concern, like the spotted owl. There has been a disproportionately high concentration of owl nest sites impacted by high severity fire in the north, primarily from several large fires that burned under very hot, dry and often windy conditions in steep terrain (e.g. Moonlight and Chips fires). Some birds, early seral or snag favoring, respond favorably to these fires (see previous focal species discussion; Chapter 1, WIKI). However, many distributed, smaller large severity patches would provide better connectivity across the bioregion, than several large, high severity patches in limited areas. A few, high severity fires, do not contribute as much to bioregional connectivity for early seral species and are detrimental to connectivity for late-seral, forest species.


A substantial proportion of key landscape areas of aquatic conservation concern, critical habitat for yellow-legged frogs and old forest mosaics (Franklin and Fites-Kaufman 1996) also have low fire resiliency. These are areas where concentrations of uncommon, ecologically important species and habitats are in otherwise good ecological condition.

Ch1_Terrestrial_Aquatic_FireRes_sm.jpg

Ch1_Terrestrial_LSOG_FireRes_sm.jpg

Ongoing efforts by the Conservation Biology Institute can be found at their website at
http://d2k78bk4kdhbpr.cloudfront.net/media/reports/files/Report_Decision-support_maps_for_Sierra_Nevada_carnivores_8_21_12.pdf


Potential Trends with Climate Change


Note: this section is in progress with many additions underway to reflect on-going current efforts, such as by the interagency California Conservation group, the national park service, researchers and others.

An interagency effort is underway to characterize and evaluate potential trends in vegetation and biodiversity in California. As part of this, projects of changes in vegetation have been developed with potential climate change (http://californialcc.org/, http://californialcc.org/projects/vulnerability-assessments, http://ecoadapt.org/programs/adaptation-consultations/calcc, http://goo.gl/Lg3Bn). There is uncertainty about what the changes in climate will be and how those changes will affect vegetation, other living things directly and indirectly through changes in habitat, environmental tolerances and fire. There is general agreement that changes are and will occur but not on how much or where. The common view overall is that at the boundaries between different vegetation types, such as the lower elevation of ponderosa pine and mixed conifer or red fir or subalpine, that there will be the most changes. In general, it is predicted that there will be an upward migration of vegetation types or species and shrinking of higher elevation or upper montane (i.e. red fir) and subalpine zones. It is unknown how fast these trends will occur.

Maps of current vs. projected future habitat type distributions and zonation analysis of priority avian conservation species targets. Maps were taken from the California LCC Environmental Change Network (http://data.prbo.org/apps/ecn/).
Chap1_Terr_08.jpg

Potential Trends with Fire



Potential Trends with Human Demographic and Land Use Trends


Under construction will likely be covered as an integrated discussion in the actual assessment document - rather than these topical papers that are broken out by different areas.

Moving Beyond Vegetation Sensing to Ensure Protection and Sustainability of Biodiversity--The Fine Filter Approach


One of the fundamental and ongoing debates in forest management is centered on the scales and intensity of monitoring wildlife species to assess responses to changes in the environment. In a recent publication in the Journal of Wildlife Management(Schultz et al. 2013) (add Link), several experts in wildlife conservation planning express concern of the Forest Service’s historic reliance on what is termed “coarse filter” approaches to monitoring wildlife species. The authors state, “Research indicates that the coarse-filter approach is unlikely to provide a reliable basis for multi-species conservation planning, (Cushman 2008), only limited testing of the approaches validity has occurred (Noon et al. 2009), and the monitoring of a select group of species using a fine-filter approach is necessary to determine the efficacy of coarse-filter approaches (Committee of Scientists 1999, Flather et al. 2009). A recent review of the degree to which coarse-filter models can be used to infer animal occurrence concluded that ‘..the observed error rates were high enough to call into question any management decisions based on these models’ (Schlossberg and King 2009).” The authors go on to state that the basic assumption that habitat is a valid proxy for species health is at best a risky stretch and at worst a weak and incomplete picture of the health, functioning and diversity of a particular ecosystem.

Another monitoring approach, also largely driven by expediency, postulates that species surrogates (indicator species) are adequate proxies for suites of species associated with various vegetation types across a landscape. In recent research (Cushman et al. 2010) examined 72,495 bird observations of 55 species across 1046 plots across 30 sub-basins and found “few significant indicator species relationships at either scale” where there was a presumed association.

In PSW-GTR-237, Managing Sierra Nevada Forests (2012) authors Malcolm North and Patricia Manley suggest that “coarse filter” approaches such as the California Wildlife-Habitat Relations model “generally fail to account for the different spatial and temporal scales at which species may respond to forest conditions or assess habitat features other than large trees and canopy cover.”

The Sierra Nevada Framework Environmental Impact Statement (2001) habitat projections for old forest attributes are an example of the coarse filter approach. Old forest habitat--large trees greater than 50 inches in diameter and large snags--were projected to increase significantly over a 140-year time scale. Oaks modeled to 60 years showed similar results. Yet, species monitoring has demonstrated that the California spotted owl, one of the key sensitive species of management concern closely tied to these habitat values, is currently experiencing a declining population trend (Keane 2013). The information regarding declining spotted owl trend was the result of fine-filter monitoring via a long-term spotted owl research project. If managers (and conservation advocates) were to rely simply upon the optimistic habitat projections in the 2001 Framework Plan and EIS (which the conservation community actively supported) we would be flying blind in what looks like an increasing grave situation for the owl’s survival.

Fine-filter monitoring approaches are less likely to oversimplify how animals use habitat and are more likely to capture effects of fine scale habitat fragmentation, predator-prey relations, behavioral responses to changed conditions, the value of understory diversity and snags and downed wood, landscape scale relationships or connectivity and spatial and temporal patterns of detection and non-detection.

In the new Forest Service Draft Directives, FSH 1909.12, Chapter 30 Monitoring, Section 32.12 “Selecting Monitoring Indicators,” stresses the financial feasibility, practicality, measurability and relevance to key monitoring questions. Section 32.13 establish eight monitoring indicators for tracking ecological conditions and progress toward desired conditions, plan objectives and important trends. Included in the directives are indicators to assess ecological conditions and status of focal species that are tied to ecological conditions.

These are generally coarse filter metrics that will be further defined in the specific revision of forest plans, including the Inyo, Sierra and Sequoia National Forest early adopter forests in California. Chapter 20 of the new Directives address the need for specific fine-filter standards when more general ecosystem indicators are not specific enough to address at-risk species needs such as nest tree protection or culverts allowing proper fish passage.

The National Forest Management Act requires the Forest Service to provide for a diversity of plant and animal species and not simply a range of ecological conditions that may or may not support diversity. The new Forest Service Planning Rule and its Directives system must ensure diversity of plant and wildlife species is maintained. The Forest Service’s obligation cannot devolve into a suite of invalid assumptions, ruled by efficiency which ultimately fail to meet the intent of the NMFA and the public’s expectation that Forest Service land managers will examine closely and rigorously the effects of management and changing conditions on the land.


Ecological Integrity - Restoration Pace and Scale

What we leave on the land, not what we take away is the essence of ecological restoration. Ecological restoration embraces a revised perspective on how lands are managed in two key ways. One is restoring ecosystems where they have been degraded from past management and are not providing for plants and animals that depend upon them. Second is ensuring the resilience, or sustainability, into the future with trends in climate, drought, and fire. Only with resilience, can forest and water ecosystems provide habitat for plants and animals, the plants and animals themselves, and ecosystem services such as water, recreation, fire resilience, and carbon regulation—all part of ecological integrity.

Many of the landscapes, distribution of plants and animals, and fire patterns have been drastically altered by human management in the last century. Some of the forests, meadows, and streamside areas have been degraded. Putting out fires was a good strategy for saving individual trees, but made forests overcrowded and susceptible to large, high intensity fires and vulnerable to and drought, insects). Large trees, and especially fire and drought resistant pines were selectively harvested, reducing habitat (food and shelter) for some specialist animals, plants, and fungi.

Intensive grazing in the late 1800’s and early 1900’s degraded meadows and resulted in streams that sunk far below natural levels (incised), removing natural flooding that sustained water-loving (wetland) plants and animals. Roads and trails were built through meadows and streams with little thought of erosion sensitive design. Extensive water development, including diversions and dams, supported a nationally important agricultural industry and growing cities and communities in the state but at the expense of natural flooding cycles that sustained stream and riverside and water plant and animal communities.

Invasive plants and animals rode the wave of these uses, taking advantage of the fur of livestock or areas cleared with logging or grazing to gain entry. Once there, they often expanded and invaded other areas, often dominating and displacing native plants and animals. Humans aided in the introduction and spread of numerous, non-native plants and animals that compete and often entirely displace native plants and animals, such as star-thistle, cheat grass, brown cowbird, or barred owls, that change fire patterns, disrupt nesting or breeding and imperil more of these species.

Management of forests, meadows, rivers, and lakes in recent decades has been more careful and scientifically based, but has not kept pace with changes in climate, fire, and sustaining needs of people. Weather is getting hotter and drier, increasing the intensity and length of fire season. Forests continue to get more overcrowded and demands for recreation opportunities in the bioregion grow. A steadily growing presence of people in towns, and scattered homes have broken up the continuity of plant and animal habitat, impeding movement of wide-ranging ones like deer, fisher, or mountain lions. Other plants and animals, with more constricted living areas (distributions) have had habitat removed all together. The rich diversity of plants and animals, that draw many people to live and visit the area have an increasing number that are considered threatened or vulnerable to future changes in weather, fire, or development.

Over time, particularly over the last 50 years, public land management agencies, such as the US Forest Service, and state agencies responsible for managing the forests, grasslands, wetland, and water ecosystems have tried to keep up with the changing ecosystem conditions and human needs. As science increases our knowledge, using a scientific basis is always a goal. Understanding the complexities of natural ecosystems and how to balance human uses will likely always remain beyond our reach to entirely capture the entirety of them and science is always changing, building upon past knowledge and refining or sometimes entirely changing ideas. In the meanwhile, ecosystems and human needs go on and the important task of sustaining the legacy for future generations and providing for current needs of both natural ecosystems and humans is a central goal. In the past several decades, as fires have become more uniformly intense , and climate has become hotter and drier (Chapter 3, WIKI), there is a need to increase the speed (pace) and breadth (scale) of management that restores forest (North, Collins and Skinner, Keane, Zielinski 2013-Science Synthesis), shrub, grass, and water ecosystems (Long et al., Hunsaker et al. 2013-Science Synthesis) so that they can withstand (resilient) these changes and still provide for native plants and animals, and all of the other services ecosystems provide such as water (State ? meadow restoration program), recreation, and rural community sustenance.

Specific strategies for increasing the pace and scale of ecosystem restoration have been identified recently by a number of scientific efforts. A number of them are summarized below, with emphasis on those that are important across large areas of the bioregion, improve or maintain,major aspects of ecological integrity, are economically and socially sustainable, and are most within reach with current resources.

Past and current management strategies for land-based (terrestrial) and water-based (aquatic) ecosystems have focused on averages or “normal” conditions. An example of this is from flood zones. Typically, zoning is focused on the average “100” year flood line. But when the “200” year flood comes, houses get flooded or levies get ruptured. Similarly, fire and forest-management have “high” fire or drought conditions, or the 90th percentile weather. With longer, hotter fire seasons already here (Westerling 2006), and increasing early and more erratic flooding and alternatively very dry years (Null and Viers 2012), this “normal” average approach is ineffective and will be more ineffective in the future. This tendency to manage for the “normal” condition, rather than the less likely but high impact events is human nature (Taleb 2007) and called the “Black Swan” syndrome. We don’t expect a black swan, and when we see one, are usually taken aback. Planning for the present and near future in the bioregion needs to consider that “normal” is changing for water, fire and drought. This can be done in several ways.

Water is of vital importance to Californians and numerous meadow and aquatic ecosystems, and these ecosystems have been identified as amongst the most vulnerable to climate change (Null and Viers 2012; Chapter 1, WIKI; Hunsaker et al. 2012; Sierra Conservancy 2012b; NPS 2013). Restoration of meadow condition has been identified by the State of California as a priority for maintaining and improving future water storage with drying climates. This will also benefit numerous species at risk from shrinking meadow habitats with warming climates (TACCIMO 2013). I second important recommendation was that In a white paper prepared by the UC Davis for the California Energy Commission, is that scientific models used to regulate water storage and releases from dams and diversions be changed from one based on “water year type” where climates are considered stationary to one where changes are assumed. Critically dry water years are expected to be 8% and 32% more likely in the northern and southern portions of the bioregion in the latter half of the century and meadow restoration and consideration in water development plans (FERC relicensing 4E conditions) that include requirements for aquatic ecosystem conservation.

For forest resiliency to fire and drought, several broad restoration strategies will be important in achieving sustainability of plant and animal habitat, as well as stability of carbon cycling, reducing poor air quality from large, high intensity wildfires, and ensuring the capacity to maintain forest resilience to future climate changes. First, much more extensive areas of the landscapes, especially forested need to be restored to more resilient conditions (Chapter 1, 3 WIKI; Collins and Skinner 2012, Science Synthesis).

Currently a small fraction of the landscape is treated, typically less than 5% and has not been effective in restoring forests so that when intense fires burn through during the hottest and driest, or windiest weather, that habitat and ecological integrity is maintained. While there is repeated documentation of strategically placed fuel treatment zones reducing fire intensity and spread, and improving effectiveness of firefighters, increasingly this only affects a small portion of the landscape. In addition to these strategically placed areas of intensive management, reduction of forest density and increasing forest patchiness or “heterogeneity” across 2/3 or more of the landscape in the lower and middle elevations (montane, ponderosa pine and mixed conifer) will be needed to effectively change fire intensity and tree kill to levels that provide for ecological integrity (carbon stability, connectivity, habitat, and fire process). Current, widely used fire prediction models do not account for the more extreme (vs average) explosive, fires that are becoming increasingly common (Brown et al. 2004, Westerling et al. 2006, Westerling and Bryant 2008, Westerling and Bryant 2008)). They still provide useful planning tools but target weather needs to be changed from 90th to 97th percentile (dry to very dry) conditions, and other tools or strategies to evaluate more explosive fires need to be addressed, even if qualitatively. One tool is currently in development by Westerling and others as part of a USDA research grant, that links the probability of very large, very severe fires with changing climate and proportion of the landscape in fire resilient states (condition classes – Barrett et al. 2010) (Westerling, personal communication).

Although the landscape nature of fires and wildlife habitat connectivity have long been recognized in national forest and other land management plans in the bioregion, they often have great detail on individual species sites, or forest stand characteristics over the short-term in guiding management. Lack of focus on the “big picture” over the landscape, distribution of species and resilience in time greatly limits reaching goals of sustainability of ecological integrity. One approach currently in progress, are landscape “adaptive management” projects, eg. Last Chance and Dinkey Creek (USFS 2010, 2011). Some have proposed distributing these across more large landscapes (Aplet and Gallo 2013). The scope of the changes needed to address changes in large fire intensity and resilience to drought will require even more extensive adaptive management, with rapid, real-time, focused monitoring and adjusting. Trends in larger, more frequent fires with early spring snowmelt are already occurring (Westerling, personal communication, in progress) and may have great impacts before large, formal adaptive management experiments are completed.

Ch1_Terrestrial_SnowMelt_sm.jpg

There are several strategies for improving the pace of restoring and maintaining forest resiliency. One is to emphasize partnerships to help offset costs for restoration treatments that reduce potential air pollution emissions and benefit carbon storage stability. Fire resilient forests provide more resilient carbon storage (North 2012, Science Synthesis; Vaillant et al. 2013) in dry, fire prone forests. Placer County has developed and is testing and innovative way to utilize partnerships amongst counties, the US Forest Service and private contractors, to use mechanical thinning and biomass removal to restore forest density and composition, while reducing potential air pollution during intense wildfires and offset costs (Springsteen et al. 2011). Stewardship contracts are one vehicle that that US Forest Service is increasing use of to enhance capacity for such innovative projects. Rapid expansion of these would allow for their more widespread application. Stewardship contracts are also a vehicle for increasing the opportunity for tribal involvement in restoring forest resiliency and ecological integrity through traditional ecological practices (TEK).

Traditional ecological practices include a wide variety of active management from reduction of forest and vegetation density through varied mechanical or hand treatments or fire to restore ecosystem conditions that provide and enhance materials and areas important to tribal cultures (Lake 2012, Science Synthesis; USFS 2013 Forest Restoration Strategic Plan). Another way to incorporate TEK and enhance capacity and increased pace of restoration is to incorporate tribal fire crews into roving, “strike teams”, specializing in fire restoration.

Economic and organizational efficiency is restoration is paramount. The need is vast but money and people are increasingly limited to achieve restoration needs that are more imminent. Strike teams of fire management crews that specialize in prescribed fires or burning for ecological integrity on managed wildlfires is a critical way to achieve two key aspects of restoring ecological integrity. Fires serve to restore large areas with relatively cheap tools, that are often less economically viable or more controversial for mechanical treatment, and restores fire as a process where fire deficits are widespread. These strike teams can also specialize in collaborative work with local fire managers, air quality and air pollution control boards that are part of successful, large projects to restore fire, and reduce future emissions and fire intensity (Vaillant et al. 2013). This approach has been successfully applied on the Sequoia National Forest and could be expanded. “Burn bosses” qualified to lead these teams are in short supply and sharing them amongst forests and with shared firefighting duties has been a limiting factor. Special burn strike teams would address this limitation.

Similarly, there are limitations on capacities needed to plan and implement more extensive thinning and biomass treatments to improve forest resiliency to high intensity fire and drought and restore ecological sustainability. Retirements and declining budgets have greatly reduced the number of experienced, high expertise persons that design and implement mechanical thinning and biomass treatments. This is particularly critical with increased requirements for ecologically sensitive treatments and effective utilization of new and evolving equipment. Similar to “strike teams” of fire restoration crews, mechanical forest restoration teams are also needed to increase the pace and scale of ecosystem restoration.

Another limitation is the infrastructure for biomass and thinning treatments. Originally, there was a large distributed infrastructure of mills developed to process large quantities of large and medium logs that were harvested from private lands for commercial timber harvest. As priorities changed and shifted to ecosystem management, a large number of the mills closed, particularly in the southern portion of the bioregion. While some were retooled to handle the smaller diameter trees that came from forest health thinning projects, some were not. Plants that take biomass removed from even smaller trees and shrubs, “ladder fuels” that carry fire from the ground up into the tops of trees, are even more limited in number and extent. This makes it uneconomical to apply these restoration tools, important for fire and drought resiliency, and many forests are left untreated as a result. Collaborative projects with counties, Department of Energy and private industry are one way that Placer County is working to remedy the situation. More collaborative efforts like this are urgently needed. While energy from biomass is more expensive at this time, increasing utility rate collections for these energy sources by 11 cents a kilowatt (Western Governors Association 2006) as proposed by the Placer County group (Springsteen et al. 2011) would address the problem as well as improve within-state energy resources.

In summary, as stated in the national US Forest Service Restoration Strategic Plan “Increasing the pace and scale of restoration of the Nation’s forests is critically needed to address a variety of threats—including fire, climate change, bark beetle infestation, and others—for the health of our forest ecosystems, watersheds, and forest-dependent communities.“

Ch1_Terrestrial_ClimateVeg_sm.jpg


Appendix – CWHR Classification Groupings


Combined cover type

Combined size class

Appendix - Wildlife Species Groups and Proposed Habitat/Ecosystem Types


Proposed Habitat/Ecosystem Types
Species
TACCIMO
CA Wildlife Strategy
USFS

Foothill Chaparral
Fox Sparrow










Oak Woodland
Blue Oak
x




Black Oak





Mule Deer





Pallid Bat




Burned Forest






Black-backed Woodpecker
x



Early Seral Forest
Mountain quail





Deer (subspecies?)




Plantation -- Conifer Agriculture
White breasted nuthatch










Mid-Seral Forest
Mountain quail










Forest with Snags
Hairy Woodpecker
















Late-Seral Open Forest

















Late-Seral Varied Canopy Forest (Closed, Patchy and Open)
Giant Sequoia groves
x




Northern Goshawk
x




California Spotted Owl
x




Flying Squirrel
x




Sierra Nevada Red Fox
x




Pacific Fisher
x




Marten
x









High Elevation Woodlands and other communities (e.g. grasslands, rock scree, cliff)
Bristle Cone Pine





Foxtail Pine





Limber Pine





Whitebark Pine





Western White Pine





Sierra Nevada Bighorn Sheep





Gray-headed Pika




Sagebrush
Greater Sage Grouse





Swainson’s hawk




Other Eastside ?













References



Additional references to consider on terrestrial ecosystems (plant communities)/climate change (reviewed in TACCIMO:http://goo.gl/Lg3Bn)):

Plant Communities - general
  • Aber, J. D., Goodale, C. L., Ollinger, S. V., Smith, M., Magill, A. H., Martin, M. E.,…Stoddard, J. L. (2001). Forest processes and global environmental change: Predicting the effects of individual and multiple stressors. BioScience, 51(9), 735-751.
  • Alpert, H. & Loik, M. E. (2013). Pinus jeffreyi establishment along a forest-shrub ecotone in eastern California, USA. Journal of Arid Environments, 90, 12 – 21.
  • Barbour, E. & Kueppers, L. M. (2011). Conservation and management of ecological systems in a changing California. Climatic Change, DOI 10.1007/s10584-011-0246-y, 1-
  • Klausmeyer, K. R., Shaw, M. R., MacKenzie, J. B. & Cameron, D. R. (2011). Landscape-scale indicators of biodiversity’s vulnerability to climate change. Ecosphere, 2(8), 1 - 18. doi:10.1890/ES11-00044.1
  • Kueppers, L. M., Snyder, M. A., Sloan, L. C., Zavaleta, E. S., & Fulfrost,B. (2005). Modeled regional climate change and California oak ranges. Proceedings of the National Academy of Sciences, 102(45), 16281-16286.
  • Lenihan, J. M., Drapek, R., Bachelet, D., & Neilson, R. P. (2003). Climate change effects on vegetation distribution, carbon, and fire in California. Ecological Applications, 13(6), 1667-1681.
  • Lenihan, J. M., Bachelet, D., Drapek, R., & Neilson, R. P. (2006). The response of vegetation distribution, ecosystem productivity, and fire in California to future climate scenarios simulated by the MC1 dynamic vegetation model. California Energy Commission, PIER Energy-Related Environmental Research Program, CEC-500-2005-191-SF, 25pp.
  • Lloret, F., Penuelas, J., Prieto, P., Llorens, L., & Estiarte, M. (2009). Plant community changes induced by experimental climate change: Seedling and adult species composition. Perspectives in Plant Ecology, Evolution and Systematics, 11, 53-63.
  • Loarie, S. R., Carter, B. E., Hayhoe, K., McMahon, S., Moe, R., Knight, C. A., & Ackerly, D. D. (2008). Climate Change and the Future of California's Endemic Flora. PLoS ONE 3(6), e2502. doi:10.1371/journal.pone.0002502
  • Lutz, J. A., Van Wagtendonk, J. W., & Franklin, J. F. (2010). Climatic water deficit, tree species ranges, and climate change in Yosemite National Park. Journal of Biogeography, 37(5), 936-950.
  • Moser, S., Franco, G., Pittiglio, W., Chou, W., & Cayan, D. (2009) The future is now: An update on climate change science impacts and response options for California. California Energy Commission Public Interest Energy Research Program, CEC-500-
  • Rehfeldt, G. E., Crookston, N. L., Saenz-Romero, C. & Campbell, E. M. (2012).North American vegetation model for land-use planning in a changing climate: a solution to large classification problems. Ecological Applications, 22 (1), 119 – 141.
  • Rice, K. J. & Emery, N. C. (2003). Managing microevolution: restoration in the face of global change. Frontiers in Ecology and the Environment, 1 (9), 469 – 478.

High elevation
  • Bunn, A. G., Waggoner, L. A. & Graumlich, L. J. (2005). Topographic mediation of growth in high elevation foxtail pine (Pinus balfouriana Grev. et Balf.) forests in the Sierra Nevada, USA. Global Ecology and Biogeography, 14, 103 – 114.
  • Diaz, H. F. & Eischeid, J. K. (2007). Disappearing "alpine tundra" Koppen climatic type in the western United States. Geophysical Research Letters, 34 (L18707), 1-4.
  • Eckert, A. J. & Eckert, M. L. (2007). Environmental and ecological effects on size class distributions of foxtail pine (Pinus balfouriana, Pinaceae) in the Klamath Mountains, California. Madrono, 54(2), 117 – 125.
  • Graham, E. A., Rundel, P. W., Kaiser, W., Lam, Y., Stealey, M. & Yuen, E.M. (2012). Fine-scale patterns of soil and plant surface temperatures in an alpine fellfield habitat, White Mountains, California. Arctic, Antarctic, and Alpine Research, 44(3), 288 – 295.
  • Hurteau, M., Zald, H. & North, M. (2007). Species-specific response to climate reconstruction in upper-elevation mixed-conifer forests of the western Sierra Nevada, California. Canadian Journal of Forest Research, 37, 1681 – 1691.
  • Hurteau, M., & North, M. (2009). Response of Arnica dealbata to climate change, nitrogen deposition, and fire. Plant Ecology, 202, 191-194.
  • Jovan, S. Lichen bioindication of biodiversity, air quality, and climate: baseline results from monitoring in Washington, Oregon, and California. (2008). General Technical Report PNW-GTR-737. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 115 p.
  • Karl, T. R., Melillo, J. M., & Peterson, T. C. (2009). Global climate change impacts in the United States. New York, NY, USA: Cambridge University Press.
  • Kelly, A. E. & Goulden, M. L. (2008). Rapid shifts in plant distribution with recent climate change. Proceedings of the National Academy of Sciences, 105 (33), 11823-11826.
  • Lloyd, A. H. & Graumlich, L. J. (1997). Holocene dynamics of treeline forests in the Sierra Nevada. Ecology, 78(4), 1199-1210.
  • Lloyd, A. H. (1997). Response of tree-line populations of foxtail pine (Pinus balfouriana) to climate variation over the last 1000 years. Canadian Journal of Forest Research, 27, 936 – 942.
  • Millar, C. I., King, J. C., Westfall, R. D., Alden, H. A. & Delany, D. L. (2006). Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin, Mono County, Sierra Nevada, CA, USA. Quaternary Research, 66, 273 –
  • Millar, C. I., Westfall, R. D., Delany, D. L., King, J. C. & Graumlich, L. J. (2004). Response of subalpine conifers in the Sierra Nevada, California, U. S. A., to 20th-century warming and decadal climate variability. Arctic, Antarctic, and Alpine Research, 36(2), 181 –
  • Salzer, M. W., Hughes, M. K., Bunn, A. G. & Kipfmueller, K. F. (2009). Recent unprecendented tree-ring growth in bristlecone pine at the highest elevations and possible causes. Proceedings of the National Academy of Sciences, 106(48), 20348 – 20353.
  • Taylor, A. H. (1995). Forest expansion and climate change in the mountain hemlock (Tsuga mertensiana) zone, Lassen Volcanic Park, California, U.S.A. Arctic and Alpine Research, 27 (3), 207-216.

Arid Lands
  • Breshears, D. D., Myers, O. B., Meyer, C. W., Barnes, F. J., Zou, C. B…. & Pockman, W. T. (2009). Tree die-off in response to global change type drought: mortality insights from a decade of plant water-potential measurements. Frontiers in Ecology and the Environment, 7, 1 – 5. doi:10.1890/080016
  • Karl, T. R., Melillo, J. M., & Peterson, T. C. (2009). Global climate change impacts in the United States. New York, NY, USA: Cambridge University Press.
  • Lawler, J. J., Tear, T. H., Pyke, C., Shaw, M. R., Gonzalez, P., Kareiva,P., Hansen, L., Hannah, L., Klausmeyer, K., Aldous, A., Bienz, C., & Pearsall, S. (2010). Resource management in a changing and uncertain climate. Frontiers in Ecology and the Environment, 8(1), 35-43.
  • Lawson, D. M., Regan, H. M., Zedlers, P. H., & Franklin, J. (2010). Cumulative effects of land use, altered fire regime and climate change on persistence of Ceanothus verrucosus, a rare, fire-dependent plant species. Global Change Biology, 16, 2518-2529. doi: 10.1111/j.1365-2486.2009.02143.x
  • Van de Ven, C. M., Weiss, S. B. & Ernst, W. G. (2007). Plant species distributions under present conditions and forecasted for warmer climates in an arid mountain range. Earth Interactions, 11 (Paper No. 9), 1 – 33.

Temperate Forests
  • Barbour, E. & Kueppers, L. M. (2011). Conservation and management of ecological systems in a changing California. Climatic Change, DOI 10.1007/s10584-011-0246-y, 1-
  • Conlisk, E., Lawson, D., Syphard, A. D., Franklin, J., Flint L, … Regan, H. M. (2012) The roles of dispersal, fecundity, and Predation in the population persistence of an oak (Quercus engelmannii) under global change. PLoS ONE, 7(5),1 – 11. e36391. doi:10.1371/journal.pone.0036391.
  • Damschen, E. I., Harrison, S., Ackerly, D. D., Fernandez-Going, B. M. & Anacker, B. L. (2012). Endemic plant communities on special soils: early victims or hardy survivors of climate change? Journal of Ecology, doi: 10.1111/j.1365-2745.2012.01986.x
  • Gauthier, M. –M. & Jacobs, D. F. (2011). Walnut (Juglans spp.) ecophysiology in response to environmental stresses and potential acclimation to climate change. Annals of Forest Science, 68(8), 1277-1290. doi: 10.1007/s13595-011-0135-6
  • Jimerson, T. M. & Carothers, S. K. (2002). Northwest California oak woodlands: environment, species composition, and ecological status. In R. B. Standiford, D. McCreary & K. L. Purcell, (technical coordinators ). Proceedings of the fifth symposium on oak woodlands: oaks in California’s changing landscape. 2001 October 22-25; San Diego, CA. General Technical Report PSW-GTR-184. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station; 846 p.
  • Lutz, J. A., van Wagtendonk, J. W., & Franklin, J. F. (2009). Twentieth-century decline of large-diameter trees in Yosemite National Park, California, USA. Forest Ecology and Management, 257, 2296-2307.
  • McLaughlin, B. C. & Zavaleta, E. S. (2012). Predicting species responses to climate change: demography and climate microrefugia in California valley oak (Quercus lobata). Global Change Biology, 18, 2301 – 2312. doi: 10.1111/j.1365-2486.2011.02630.x
  • Rogers, P. C., Shepperd, W. D. & Bartos, D. L. (2007). Aspen in the Sierra Nevada: Regional conservation of a continental species. Natural Areas Journal, 27 (2), 183 –
  • Royce, E. B. & Barbour, M. G. (2001). Mediterranean climate effects. II. Conifer growth phenology across a Sierra Nevada ecotone. American Journal of Botany, 88(5), 919 –
  • Sork, V. L., Davis, F. W., Westfall, R., Flint, A., Ikegami, M., Wang, H., & Grivet, D. (2010). Gene movement and genetic association with regional climate gradients in California valley oak (Quercus lobata Nйe) in the face of climate change. Molecular Ecology, 19, 3806–3823. doi: 10.1111/j.1365-294X.2010.04726.x
  • Spero, J. G. (2002). Development and fire trends in oak woodlands of the northwestern Sierra Nevada foothills. In R. B. Standiford, D. McCreary & K. L. Purcell (technical coordinators): Proceedings of the fifth symposium on oak woodlands: oaks in California’s changing landscape. 2001 October 22-25; San Diego, CA. General Technical Report PSW-GTR-184. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station; 846 p.
  • York, R. A., Fuchs, D., Battles, J. J., & Stephens, S. L. (2010). Radial growth responses to gap creation in large, old Sequoiadendron giganteum. Applied Vegetation Science, 13(4), 498-509.

Additional Terrestrial References

  • Alexander, J. D., N. E. Seavy, and P. E. Hosten. (2007). Using Conservation Plans and Bird Monitoring to Evaluate Ecological Effects of Management: An Example with Fuels Reduction Activities in Southwest Oregon. Forest Ecology and Management 238: 375–383.
  • Aubrey, K.B. and C.M. Raley. 2006. Ecological characteristics of fishers (Martes pennanti) in the Southern Oregon Cascade Range. USDA Forest Service, Pacific Northwest Research Station, Olympia Forestry Sciences Laboratory, Olympia, WA.
  • Aubry, K.B., C.M Raley, S.W. Buskirk, W.J. Zielinski, M.W. Schwartz, R.T. Golightly, K.L. Purcell, R.D. Weir and J.S. Yaeger. Submitted. Meta-analysis of habitat selection at resting sites by fishers in the Pacific Coastal states and provinces. Journal of Wildlife Management.
  • Aubry K.B., Zielinski W.J., Raphael M.G., Proulx G., and Buskirk, S.W., eds. 2012. Biology and Conservation of Martens, Sables and Fishers: A New Synthesis. Cornell Univ. Press, Ithaca, NY. 580pp.
  • Buskirk, A.S. Harestad, M.G. Raphael, and R.A. Powell, editors. 1994. Martens, sables and fishers: biology and conservation. Cornell University Press, Ithaca, NY. 484 pp.
  • California Department of Fish and Game. 2010. A status review of the fisher (Martes pennanti) in California. Report to the Fish and Game Commission. Sacramento, CA. 104 pp. + appendices.
  • Buskirk, S.W., and L.R. Ruggiero. 1994. American marten. Pages 7-37 in American marten, fisher, lynx, and wolverine in the western United States (L.F. Ruggiero, K.B. Aubry, S.W. Buskirk, L.J. Lyon, and W.J. Zielinski, editors). United States Department of Agriculture Forest Service General Technical Report. RM-254.
  • Chase, M. K. & Geupel, G. R. (2005). The Use of Avian Focal Species for Conservation Planning in California. In: Ralph, C. John; Rich, Terrell D., editors 2005. Bird Conservation Implementation and Integration in the Americas: Proceedings of the Third International Partners in Flight Conference. 2002 March 20-24; Asilomar, California, Volume 1 Gen. Tech. Rep. PSW-GTR-191. Albany, CA: U.S. Dept. of Agriculture, Forest Service, Pacific Southwest Research Station: p. 130-142
  • Ellis, L.M. 1998. Habitat-use patterns of the American marten in the southern Cascade mountains of California, 1992-1994. Master’s thesis. Department of Wildlife, Humboldt State University, Arcata, CA.
  • Gabriel, M.W. 2013. Integral Ecology Research Center. Grow site impacts and new mortalities from anticoagulant rodenticides. Presentation at the Western Section of The Wildlife Society. Sacramento, CA. Jan. 30 – Feb. 1, 2013.
  • Grenfell, W.E. and M. Fasenfest. 1979. Winter food habits of fishers, Martes pennanti, in northwestern California. Calif. Fish and Game 65:186-189.
  • Grinnell, J., J.S. Dixon, and J.M. Linsdale. 1937. Fur-bearing mammals of California. Vol. 1. University of California Press, Berkeley, CA. 375 pp.
  • Hargis, C. D., Bissonette, John. A. and Turner, D. L. 1999. The influence of forest fragmentation and landscape pattern on American martens. Journal of Applied Ecology, 36: 157–172. doi: 10.1046/j.1365-2664.1999.00377.x
  • Kirk, T.A., and W.J. Zielinski. 2009. Developing and testing a landscape habitat suitability model for the American marten (Martes americana) in the Cascades mountains of California. Landscape Ecology 24:759-773.
  • Knaus, B.J., R. Cronn, A. Liston, K. Pilgrim, and M.K. Schwartz. 2011. Mitochondrial genome sequences illuminate maternal lineages of conservation concern in rare carnivore. BMC Ecology 2011 11:10.
  • Lofroth, E. C., C. M. Raley, J. M. Higley, R. L. Truex, J. S. Yaeger, J. C. Lewis, P. J. Happe, L. L. Finley, R. H. Naney, L. J. Hale, A. L. Krause, S. A. Livingston, A. M. Myers, and R. N. Brown. 2010. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California–Volume I: Conservation Assessment. USDI Bureau of Land Management, Denver, Colorado, USA. 163pp.
  • Lofroth, E. C., J. M. Higley, R. H. Naney, C. M. Raley, J. S. Yaeger, S. A. Livingston, and R. L. Truex. 2011. Conservation of Fishers (Martes pennanti) in South-Central British Columbia, Western Washington, Western Oregon, and California–Volume II: Key Findings From Fisher Habitat Studies in British Columbia, Montana, Idaho, Oregon, and California. USDI Bureau of Land Management, Denver, Colorado, USA. 117pp.
  • Mazzoni, A. 2002. Habitat use by fishers (Martes pennanti) in the southern Sierra Nevada, California. M.S. Thesis. California State University, Fresno, CA.
  • Naney, R. H., L. L Finley, E. C. Lofroth, P. J. Happe, A. L. Krause, C. M. Raley, R. L. Truex, L. J. Hale, J. M. Higley, A. D. Kosic, J. C. Lewis, S. A. Livingston, D. C. Macfarlane, A. M. Myers, and J. S. Yaeger. 2012. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California–Volume III: Threat Assessment. USDI Bureau of Land Management, Denver, Colorado, USA. 55pp.
  • North, M., P. Stine, K. O’Hara, W. Zielinski, and S. Stephens. 2009. An ecosystem management strategy for Sierran mixed conifer forests. General technical report PSW-GTR-220. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 49 pages.
  • Powell RA. 1993. The fisher: life history, ecology and behavior. 2nd ed. Minneapolis: University of Minnesota Press.
  • Spencer, W.D., H.L. Rustigian, R.M. Scheller, A. Syphard, J. Strittholt, and B. Ward. 2008. Baseline evaluation of fisher habitat and population status, and effects of fires and fuels management on fishers in the southern Sierra Nevada. Unpublished report for USDA Forest Service, Pacific Southwest Region. Conservation Biology Institute. Corvallis, OR. 133 pp + appendices.
  • Spencer, W.D., H. Rustigian-Romsos, J. Strittholt, R. Scheller, W. Zielinski, and R. Truex. 2011. Using occupancy and population models to assess habitat conservation opportunities for an isolated carnivore population. Biological Conservation 144: 788-803.
  • Spencer, W. and H. Rustigian-Romsos. 2012. Decision-support maps and recommendations for conserving rare carnivores in the interior mountains of California. Unpublished report for Sierra Forest Legacy. 37pp.
  • Stephens, J. L., K. Kreitinger, C. J. Ralph, and M. T. Green, eds. (2011). Informing Ecosystem Management: Science and Process for Landbird Conservation in the Western United States. Biological Technical Publication FWS/BTP-R1014-2011. Portland, Oregon: U.S. Department of Interior, Fish and Wildlife Service. http://library.fws.gov/BTP/information-ecosystem-management-2011.pdf.
  • Thompson, C., K. Purcell, J. Garner and R. Green. 2009. Kings River Fisher Project. Two-year preliminary progress report presented to the Western Section of The Wildlife Society meeting, January 21-23, 2009. Sacramento, California.
  • Truex, R.L. W.J. Zielinski, J.S. Bolis, and J.M. Tucker. 2009. Fisher population monitoring in the southern Sierra Nevada, 2002 – 2008. Paper presented at the 5th International Martes Symposium, Seattle, WA. September 8–12, 2009.
  • Tucker, J.M., M.K. Schwartz, K.L. Pilgrim, and F.W. Allendorf. 2012. Historical and contemporary DNA indicate fisher decline and isolation occurred prior to the European settlement of California. PLoS ONE 7(12): e52803. doi: 10.1371/journal.pone.0052803
  • USDA Forest Service. 2006. Sierra Nevada forest plan accomplishment monitoring report for 2005. USDA Forest Service, Pacific Southwest Region R5-MR-000. 12pp.
  • Weir, R.D. 2003. Status of the fisher in British Columbia. British Columbia Ministry of Sustainable Resource Management, Conservation Data Center, and the Ministry of Water, Land, and Air Protection, Biodiversity Branch. Victoria, British Columbia, Canada.
  • Wiens, J. A., Hayward, G. D., Hoilthause, R. S., Wisdom, M. J. (2008). Using Surrogate Species and Groups for Conservation Planning and Management. Bioscience, 58(3), 241-252.
  • Zielinski, W.J. 2013. The forest carnivores: fisher and marten. Pages xxx-xxx in: Long, Jonathan; Skinner, Carl; North, Malcolm; Winter, Pat; Zielinski, Bill; Hunsaker, Carolyn; Collins, Brandon; Keane, John; Lake, Frank; Wright, Jessica; Moghaddas, Emily; Jardine, Angela; Hubbert, Ken; Pope, Karen; Bytnerowicz, Andrzej; Fenn, Mark; Busse, Matt; Charnley, Susan; Patterson, Trista; Quinn-Davidson, Lenya; Safford, Hugh; chapter authors and Synthesis team members. Bottoms, Rick; Hayes, Jane; team coordination and review. Meyer, Marc; Herbst, David; Matthews, Kathleen; additional contributors. USDA Forest Service Pacific Southwest Research Station. 2013. Science Synthesis to support Forest Plan Revision in the Sierra Nevada and Southern Cascades. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 504 p.
  • Zielinski, W.J, R.L. Truex, J.R. Dunk and T. Gaman. 2006. Using forest inventory data to assess fisher resting habitat suitability in California. Ecological Applications 16:1010-1025.
  • Zielinski, W.J., R.L. Truex, C.V. Ogan, and K.Busse.1997. Detection surveys for fishers and American martens in California, 1989-1994: Summary and interpretations. Pages 372-392. In G. Proulx, H.N. Bryant, and P.M. Woodard, editors. Martes: taxonomy, ecology, techniques and management. Provincial Museum of Alberta, Alberta, Canada.
  • Zielinski, W.J., R.L. Truex, R. Schlexer, L.A. Campbell, and C. Carroll. 2005. Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California. J. Biogeog. 32:1385-1407.
  • Zielinski, W.J, R.L. Truex, F.V. Schlexer, L.A. Campbell, and C. Carroll. 2005. Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California, U.S.A. Journal of Biogeography 32:1385-1407.
  • Zielinski, W.J., R.L. Truex, G.A. Schmidt, F.V. Schlexer, K.N. Schmidt, and R.H. Barrett. 2004a. Resting habitat selection by fishers in California. J. Wildl. Mngt. 68(3):475-492.
  • Zielinski, W.J., R.L. Truex, G.A. Schmidt, F.V. Schlexer, K.N. Schmidt, and R.H. Barrett. 2004b. Home range characteristics of fishers in California. J. Mammalogy, 85(4):649–657.
  • Zielinski, W.J., J.A. Baldwin, R.L. Truex, J.M. Tucker, and P.A. Flebbe. 2013. Estimating trend in occupancy for the southern Sierra fisher Martes pennanti population. Journal of Fish and Wildlife Management 4(1):xx-xx; e1944-687x. doi: 10:3996/012012-JFWM-002. 17p.


Additional references to consider on terrestrial ecosystems (animal communities)/climate change (reviewed in TACCIMO:**http://goo.gl/Lg3Bn)**):

  • A’Bear, A. D., Boddy, L. & Jones, T. H. (2012). Impacts of elevated temperature on the growth and functioning of decomposer fungi are influenced by grazing collembola. Global Change Biology, 18, 1823 – 1832.
  • Aber, J. D., Goodale, C. L., Ollinger, S. V., Smith, M., Magill, A. H., Martin, M. E.,…Stoddard, J. L. (2001). Forest processes and global environmental change: Predicting the effects of individual and multiple stressors. BioScience, 51(9), 735-751.
  • Alpert, H. & Loik, M. E. (2013). Pinus jeffreyi establishment along a forest-shrub ecotone in eastern California, USA. Journal of Arid Environments, 90, 12 – 21.
  • Barbour, E. & Kueppers, L. M. (2011). Conservation and management of ecological systems in a changing California. Climatic Change, DOI 10.1007/s10584-011-0246-y, 1-
  • Blois, J. L., McGuire, J. L. & Hadly, E. A. (2010). Small mammal diversity loss in response to late-Pleistocene climatic change. Nature, 465, 771 – 775.
  • Bruzgul, J. & Root, T. L. (2010) Temperature and long-term breeding trends in California birds: Utilizing and undervalued historical database. California Energy Commission, PIER Energy-Related Environmental Research Program, CEC-500-2010-002.
  • Breshears, D. D., Myers, O. B., Meyer, C. W., Barnes, F. J., Zou, C. B…. & Pockman, W. T. (2009). Tree die-off in response to global change type drought: mortality insights from a decade of plant water-potential measurements. Frontiers in Ecology and the Environment, 7, 1 – 5. doi:10.1890/080016
  • Bunn, A. G., Waggoner, L. A. & Graumlich, L. J. (2005). Topographic mediation of growth in high elevation foxtail pine (Pinus balfouriana Grev. et Balf.) forests in the Sierra Nevada, USA. Global Ecology and Biogeography, 14, 103 – 114.
  • Conlisk, E., Lawson, D., Syphard, A. D., Franklin, J., Flint L, … Regan, H. M. (2012) The roles of dispersal, fecundity, and Predation in the population persistence of an oak (Quercus engelmannii) under global change. PLoS ONE, 7(5),1 – 11. e36391. doi:10.1371/journal.pone.0036391.
  • Dahlhoff, E. P., Fearnley, S. L., Bruce, D. A., Gibbs, A. G., Stoneking, R., … & Rank, N. E. (2008). Effects of temperature on physiology and reproductive success of a montane leaf beetle: Implications for persistence of native populations enduring climate change. Physiological and Biochemical Zoology, 81(6), 718 – 732.
  • Damschen, E. I., Harrison, S., Ackerly, D. D., Fernandez-Going, B. M. & Anacker, B. L. (2012). Endemic plant communities on special soils: early victims or hardy survivors of climate change? Journal of Ecology, doi: 10.1111/j.1365-2745.2012.01986.x
  • Diaz, H. F. & Eischeid, J. K. (2007). Disappearing "alpine tundra" Koppen climatic type in the western United States. Geophysical Research Letters, 34 (L18707), 1-4.
  • Eastman, L. M., Morelli, T. L., Rowe, K.C., Conroy, C. J. & Moritz, C. (2012). Size increase in high elevation ground squirrels over the last century. Global Change Biology, 18, 1499 – 1508.
  • Eckert, A. J. & Eckert, M. L. (2007). Environmental and ecological effects on size class distributions of foxtail pine (Pinus balfouriana, Pinaceae) in the Klamath Mountains, California. Madrono, 54(2), 117 – 125.
  • Forister, M. L., McCall, A. C., Sanders, N. J., Fordyce, J. A., Thorne, J. H., O'Brien, J., Waetjen, D. P., & Shapiro, A.M. (2010). Compounded effects of climate change and habitat alteration shift patterns of butterfly diversity. Proceedings of the National Academy of Science, 107 (5), 2088-2092.
  • Gardali, T., Howell, C. A., Seavy, N. E. Shuford, W. D. & Stralberg, D. (2011). Projected effects of climate change in California: Ecoregional summaries emphasizing consequences for wildlife, Version 1.0. Petaluma, CA: PRBO Conservation Science. 68pp. http://data.prbo.org/apps/bssc/climatechange
  • Gauthier, M. –M. & Jacobs, D. F. (2011). Walnut (Juglans spp.) ecophysiology in response to environmental stresses and potential acclimation to climate change. Annals of Forest Science, 68(8), 1277-1290. doi: 10.1007/s13595-011-0135-6
  • Goodman, R. E., Lebuhn, G., Seavy, N.E., Gardali, T., & Bluso-Demers, J. D.(2012). Avian body size changes and climate change: warming or increasing variability? Global Change Biology, 18, 63-73.
  • Graham, E. A., Rundel, P. W., Kaiser, W., Lam, Y., Stealey, M. & Yuen, E.M. (2012). Fine-scale patterns of soil and plant surface temperatures in an alpine fellfield habitat, White Mountains, California. Arctic, Antarctic, and Alpine Research, 44(3), 288 – 295.
  • Hurteau, M., Zald, H. & North, M. (2007). Species-specific response to climate reconstruction in upper-elevation mixed-conifer forests of the western Sierra Nevada, California. Canadian Journal of Forest Research, 37, 1681 – 1691.
  • Hurteau, M., & North, M. (2009). Response of Arnica dealbata to climate change, nitrogen deposition, and fire. Plant Ecology, 202, 191-194.
  • Jimerson, T. M. & Carothers, S. K. (2002). Northwest California oak woodlands: environment, species composition, and ecological status. In R. B. Standiford, D. McCreary & K. L. Purcell, (technical coordinators ). Proceedings of the fifth symposium on oak woodlands: oaks in California’s changing landscape. 2001 October 22-25; San Diego, CA. General Technical Report PSW-GTR-184. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station; 846 p.
  • Jovan, S. Lichen bioindication of biodiversity, air quality, and climate: baseline results from monitoring in Washington, Oregon, and California. (2008). General Technical Report PNW-GTR-737. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 115 p.
  • Karl, T. R., Melillo, J. M., & Peterson, T. C. (2009). Global climate change impacts in the United States. New York, NY, USA: Cambridge University Press.
  • Kelly, A. E. & Goulden, M. L. (2008). Rapid shifts in plant distribution with recent climate change. Proceedings of the National Academy of Sciences, 105 (33), 11823-11826.
  • Klausmeyer, K. R., Shaw, M. R., MacKenzie, J. B. & Cameron, D. R. (2011). Landscape-scale indicators of biodiversity’s vulnerability to climate change. Ecosphere, 2(8), 1 - 18. doi:10.1890/ES11-00044.1
  • Kueppers, L. M., Snyder, M. A., Sloan, L. C., Zavaleta, E. S., & Fulfrost,B. (2005). Modeled regional climate change and California oak ranges. Proceedings of the National Academy of Sciences, 102(45), 16281-16286.
  • Lawler, J. J., Tear, T. H., Pyke, C., Shaw, M. R., Gonzalez, P., Kareiva,P., Hansen, L., Hannah, L., Klausmeyer, K., Aldous, A., Bienz, C., & Pearsall, S. (2010). Resource management in a changing and uncertain climate. Frontiers in Ecology and the Environment, 8(1), 35-43.
  • Lawson, D. M., Regan, H. M., Zedlers, P. H., & Franklin, J. (2010). Cumulative effects of land use, altered fire regime and climate change on persistence of Ceanothus verrucosus, a rare, fire-dependent plant species. Global Change Biology, 16, 2518-2529. doi: 10.1111/j.1365-2486.2009.02143.x
  • Lenihan, J. M., Drapek, R., Bachelet, D., & Neilson, R. P. (2003). Climate change effects on vegetation distribution, carbon, and fire in California. Ecological Applications, 13(6), 1667-1681.
  • Lenihan, J. M., Bachelet, D., Drapek, R., & Neilson, R. P. (2006). The response of vegetation distribution, ecosystem productivity, and fire in California to future climate scenarios simulated by the MC1 dynamic vegetation model. California Energy Commission, PIER Energy-Related Environmental Research Program, CEC-500-2005-191-SF, 25pp.
  • Lloret, F., Penuelas, J., Prieto, P., Llorens, L., & Estiarte, M. (2009). Plant community changes induced by experimental climate change: Seedling and adult species composition. Perspectives in Plant Ecology, Evolution and Systematics, 11, 53-63.
  • Loarie, S. R., Carter, B. E., Hayhoe, K., McMahon, S., Moe, R., Knight, C. A., & Ackerly, D. D. (2008). Climate Change and the Future of California's Endemic Flora. PLoS ONE 3(6), e2502. doi:10.1371/journal.pone.0002502
  • Lutz, J. A., Van Wagtendonk, J. W., & Franklin, J. F. (2010). Climatic water deficit, tree species ranges, and climate change in Yosemite National Park. Journal of Biogeography, 37(5), 936-950.
  • Lloyd, A. H. (1997). Response of tree-line populations of foxtail pine (Pinus balfouriana) to climate variation over the last 1000 years. Canadian Journal of Forest Research, 27, 936 – 942
  • Lloyd, A. H. & Graumlich, L. J. (1997). Holocene dynamics of treeline forests in the Sierra Nevada. Ecology, 78(4), 1199-1210.
  • Lutz, J. A., van Wagtendonk, J. W., & Franklin, J. F. (2009). Twentieth-century decline of large-diameter trees in Yosemite National Park, California, USA. Forest Ecology and Management, 257, 2296-2307.
  • McLaughlin, B. C. & Zavaleta, E. S. (2012). Predicting species responses to climate change: demography and climate microrefugia in California valley oak (Quercus lobata). Global Change Biology, 18, 2301 – 2312. doi: 10.1111/j.1365-2486.2011.02630.x
  • Macmynowski, D. P., Root, T. L., Ballard, G. & Geupel, G. R. (2007). Changes in spring arrival of Nearctic-Neotropical migrants attributed to multiscalar climate. Global Change Biology, 13, 2239 – 2251. doi: 10.1111/j.1365-2486.2007.01448.x
  • Millar, C. I., King, J. C., Westfall, R. D., Alden, H. A. & Delany, D. L. (2006). Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin, Mono County, Sierra Nevada, CA, USA. Quaternary Research, 66, 273 –
  • Millar, C. I., Westfall, R. D., Delany, D. L., King, J. C. & Graumlich, L. J. (2004). Response of subalpine conifers in the Sierra Nevada, California, U. S. A., to 20th-century warming and decadal climate variability. Arctic, Antarctic, and Alpine Research, 36(2), 181 –
  • Monzon, J., Moyer-Homer, L., & Palamar, M. B. (2011). Climate change and species range dynamics in protected areas. BioScience, 61(10), 752-761.
  • Moritz, C., Patton, J. L., Conroy, C. J., Parra, J. L., White, G. C., & Beissinger, S. R. (2008). Impact of a century of climate change on small-mammal communities in Yosemite National Park, USA. Science, 322, 261-264.
  • Moser, S., Franco, G., Pittiglio, W., Chou, W., & Cayan, D. (2009) The future is now: An update on climate change science impacts and response options for California. California Energy Commission Public Interest Energy Research Program, CEC-500-
  • Parra, J. L. & Monahan, W. B. (2008). Variability in 20th century climate change reconstructions and its consequences for predicting geographic responses of California mammals. Global Change Biology, 14, 1-17.
  • Preston, K. L., Rotenberry, J. T., Redak, R.A., & Allen, M. F. (2008). Habitat shifts of endangered species under altered climate conditions: importance of biotic interactions. Global Change Biology, 14, 2501-2525.
  • Rehfeldt, G. E., Crookston, N. L., Saenz-Romero, C. & Campbell, E. M. (2012).North American vegetation model for land-use planning in a changing climate: a solution to large classification problems. Ecological Applications, 22 (1), 119 – 141.
  • Rice, K. J. & Emery, N. C. (2003). Managing microevolution: restoration in the face of global change. Frontiers in Ecology and the Environment, 1 (9), 469 – 478.
  • Rogers, P. C., Shepperd, W. D. & Bartos, D. L. (2007). Aspen in the Sierra Nevada: Regional conservation of a continental species. Natural Areas Journal, 27 (2), 183 –
  • Royce, E. B. & Barbour, M. G. (2001). Mediterranean climate effects. II. Conifer growth phenology across a Sierra Nevada ecotone. American Journal of Botany, 88(5), 919 –
  • Rubidge, E. M., Monahan, W. B., Parra, J. L., Cameron, S. E., & Brashares, J. S. (2011). The role of climate, habitat, and species co-occurrence as drivers of change in small mammal distributions over the past century. Global Change Biology, 17, 696-708. doi: 10.1111/j.1365-2486.2010.02297.x
  • Rubidge, E. M., Patton, J. L., Lim, M., Burton, A. C., Brashares, J. S. & Moritz, C. (2012).Climate-induced range contraction drives genetic erosion in an alpine mammal. Nature, 2, 285 – 288.
  • Salzer, M. W., Hughes, M. K., Bunn, A. G. & Kipfmueller, K. F. (2009). Recent unprecendented tree-ring growth in bristlecone pine at the highest elevations and possible causes. Proceedings of the National Academy of Sciences, 106(48), 20348 – 20353.
  • Sork, V. L., Davis, F. W., Westfall, R., Flint, A., Ikegami, M., Wang, H., & Grivet, D. (2010). Gene movement and genetic association with regional climate gradients in California valley oak (Quercus lobata Nйe) in the face of climate change. Molecular Ecology, 19, 3806–3823. doi: 10.1111/j.1365-294X.2010.04726.x
  • Spero, J. G. (2002). Development and fire trends in oak woodlands of the northwestern Sierra Nevada foothills. In R. B. Standiford, D. McCreary & K. L. Purcell (technical coordinators): Proceedings of the fifth symposium on oak woodlands: oaks in California’s changing landscape. 2001 October 22-25; San Diego, CA. General Technical Report PSW-GTR-184. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station; 846 p.
  • Stralberg, D., Jongsomjit, D., Howell, C. A., Snyder, M. A., Alexander, J. D.,.... & Root, T. L. (2009). Re-shuffling of species with climate disruption: A no-analog future for California birds? PLoS ONE, 4 (9), 1 - 8. doi:10.1371/journal.pone.0006825
  • Taylor, A. H. (1995). Forest expansion and climate change in the mountain hemlock (Tsuga mertensiana) zone, Lassen Volcanic Park, California, U.S.A. Arctic and Alpine Research, 27 (3), 207-216.
  • Tingley, M. W., Monahan, W. B., Beissinger, S. R. & Moritz, C. (2009). Birds track their Grinnellian niche through a century of climate change. Proceedings of the National Academy of Sciences, 106 (2), 19637 – 19643.
  • Tingley, M. W., Koo, M. S., Moritz, C., Rush, A. C. & Beissinger, S. R. (2012). The push and pull of climate change causes heterogeneous shifts in avian elevational ranges. Global Change Biology, doi: 10.1111/j.1365-2486.2012.02784.x
  • Van de Ven, C. M., Weiss, S. B. & Ernst, W. G. (2007). Plant species distributions under present conditions and forecasted for warmer climates in an arid mountain range. Earth Interactions, 11 (Paper No. 9), 1 – 33.
  • Yang, D. -S., Conroy, C. J., & Moritz, C. (2011). Contrasting responses of Peromyscus mice of Yosemite National Park to recent climate change. Global Change Biology, 17,
  • York, R. A., Fuchs, D., Battles, J. J., & Stephens, S. L. (2010). Radial growth responses to gap creation in large, old Sequoiadendron giganteum. Applied Vegetation Science, 13(4), 498-509.


Additional references to consider on terrestrial ecosystems (animal communities)/climate change (reviewed in TACCIMO:http://goo.gl/Lg3Bn)):

Animal Communities - general
  • Barbour, E. & Kueppers, L. M. (2011). Conservation and management of ecological systems in a changing California. Climatic Change, DOI 10.1007/s10584-011-0246-y, 1-
  • Gardali, T., Howell, C. A., Seavy, N. E. Shuford, W. D. & Stralberg, D. (2011). Projected effects of climate change in California: Ecoregional summaries emphasizing consequences for wildlife, Version 1.0. Petaluma, CA: PRBO Conservation Science. 68pp. http://data.prbo.org/apps/bssc/climatechange
  • Preston, K. L., Rotenberry, J. T., Redak, R.A., & Allen, M. F. (2008). Habitat shifts of endangered species under altered climate conditions: importance of biotic interactions. Global Change Biology, 14, 2501-2525

Birds
  • Bruzgul, J. & Root, T. L. (2010) Temperature and long-term breeding trends in California birds: Utilizing and undervalued historical database. California Energy Commission, PIER Energy-Related Environmental Research Program, CEC-500-2010-002.
  • Goodman, R. E., Lebuhn, G., Seavy, N.E., Gardali, T., & Bluso-Demers, J. D.(2012). Avian body size changes and climate change: warming or increasing variability? Global Change Biology, 18, 63-73.
  • Macmynowski, D. P., Root, T. L., Ballard, G. & Geupel, G. R. (2007). Changes in spring arrival of Nearctic-Neotropical migrants attributed to multiscalar climate. Global Change Biology, 13, 2239 – 2251. doi: 10.1111/j.1365-2486.2007.01448.x
  • Monzon, J., Moyer-Homer, L., & Palamar, M. B. (2011). Climate change and species range dynamics in protected areas. BioScience, 61(10), 752-761.
  • Preston, K. L., Rotenberry, J. T., Redak, R.A., & Allen, M. F. (2008). Habitat shifts of endangered species under altered climate conditions: importance of biotic interactions. Global Change Biology, 14, 2501-2525.
  • Stralberg, D., Jongsomjit, D., Howell, C. A., Snyder, M. A., Alexander, J. D.,.... & Root, T. L. (2009). Re-shuffling of species with climate disruption: A no-analog future for California birds? PLoS ONE, 4 (9), 1 - 8. doi:10.1371/journal.pone.0006825
  • Tingley, M. W., Monahan, W. B., Beissinger, S. R. & Moritz, C. (2009). Birds track their Grinnellian niche through a century of climate change. Proceedings of the National Academy of Sciences, 106 (2), 19637 – 19643.
  • Tingley, M. W., Koo, M. S., Moritz, C., Rush, A. C. & Beissinger, S. R. (2012). The push and pull of climate change causes heterogeneous shifts in avian elevational ranges. Global Change Biology, doi: 10.1111/j.1365-2486.2012.02784.x

Invertebrates
  • A’Bear, A. D., Boddy, L. & Jones, T. H. (2012). Impacts of elevated temperature on the growth and functioning of decomposer fungi are influenced by grazing collembola. Global Change Biology, 18, 1823 – 1832.
  • Dahlhoff, E. P., Fearnley, S. L., Bruce, D. A., Gibbs, A. G., Stoneking, R., … & Rank, N. E. (2008). Effects of temperature on physiology and reproductive success of a montane leaf beetle: Implications for persistence of native populations enduring climate change. Physiological and Biochemical Zoology, 81(6), 718 – 732.
  • Forister, M. L., McCall, A. C., Sanders, N. J., Fordyce, J. A., Thorne, J. H., O'Brien, J., Waetjen, D. P., & Shapiro, A.M. (2010). Compounded effects of climate change and habitat alteration shift patterns of butterfly diversity. Proceedings of the National Academy of Science, 107 (5), 2088-2092.

Mammals
  • Blois, J. L., McGuire, J. L. & Hadly, E. A. (2010). Small mammal diversity loss in response to late-Pleistocene climatic change. Nature, 465, 771 – 775.
  • Eastman, L. M., Morelli, T. L., Rowe, K.C., Conroy, C. J. & Moritz, C. (2012). Size increase in high elevation ground squirrels over the last century. Global Change Biology, 18, 1499 – 1508.
  • Moritz, C., Patton, J. L., Conroy, C. J., Parra, J. L., White, G. C., & Beissinger, S. R. (2008). Impact of a century of climate change on small-mammal communities in Yosemite National Park, USA. Science, 322, 261-264.
  • Parra, J. L. & Monahan, W. B. (2008). Variability in 20th century climate change reconstructions and its consequences for predicting geographic responses of California mammals. Global Change Biology, 14, 1-17.
  • Rubidge, E. M., Monahan, W. B., Parra, J. L., Cameron, S. E., & Brashares, J. S. (2011). The role of climate, habitat, and species co-occurrence as drivers of change in small mammal distributions over the past century. Global Change Biology, 17, 696-708. doi: 10.1111/j.1365-2486.2010.02297.x
  • Rubidge, E. M., Patton, J. L., Lim, M., Burton, A. C., Brashares, J. S. & Moritz, C. (2012).Climate-induced range contraction drives genetic erosion in an alpine mammal. Nature, 2, 285 – 288.
  • Yang, D. -S., Conroy, C. J., & Moritz, C. (2011). Contrasting responses of Peromyscus mice of Yosemite National Park to recent climate change. Global Change Biology, 17,

Additional Fisher References
  • Aubry, K.B., S.M. Wisely, C.M. Raley, and S.W. Buskirk. 2004. Zoogeography, spacing patterns, and dispersal in fishers: insights gained from combining field and genetic data. p. 201-220 In D. J. Harrison and A. K. Fuller, eds. Proceedings of the 3rd International Martes Symposium: Martens and fishers (Martes) in human-altered environments: an international perspective. Springer, US. 279p.
  • Aubry K.B., Zielinski W.J., Raphael M.G., Proulx G., and Buskirk, S.W., eds. 2012. Biology and Conservation of Martens, Sables and Fishers: A New Synthesis. Cornell Univ. Press, Ithaca, NY. 580pp.
  • Aubrey, K.B. and C.M. Raley. 2006. Ecological characteristics of fishers (Martes pennanti) in the Southern Oregon Cascade Range. USDA Forest Service, Pacific Northwest Research Station, Olympia Forestry Sciences Laboratory, Olympia, WA.
  • Aubry K.B., Zielinski W.J., Raphael M.G., Proulx G., and Buskirk, S.W., eds. 2012. Biology and Conservation of Martens, Sables and Fishers: A New Synthesis. Cornell Univ. Press, Ithaca, NY. 580pp.
  • Buskirk, A.S. Harestad, M.G. Raphael, and R.A. Powell, editors. 1994. Martens, sables and fishers: biology and conservation. Cornell University Press, Ithaca, NY. 484 pp.
  • California Department of Fish and Game. 2010. A status review of the fisher (Martes pennanti) in California. Report to the Fish and Game Commission. Sacramento, CA. 104 pp. + appendices.
  • Grenfell, W.E. and M. Fasenfest. 1979. Winter food habits of fishers, Martes pennanti, in northwestern California. Calif. Fish and Game 65:186-189.
  • Lofroth, E. C., C. M. Raley, J. M. Higley, R. L. Truex, J. S. Yaeger, J. C. Lewis, P. J. Happe, L. L. Finley, R. H. Naney, L. J. Hale, A. L. Krause, S. A. Livingston, A. M. Myers, and R. N. Brown. 2010. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California–Volume I: Conservation Assessment. USDI Bureau of Land Management, Denver, Colorado, USA. 163pp.
  • Lofroth, E. C., J. M. Higley, R. H. Naney, C. M. Raley, J. S. Yaeger, S. A. Livingston, and R. L. Truex. 2011. Conservation of Fishers (Martes pennanti) in South-Central British Columbia, Western Washington, Western Oregon, and California–Volume II: Key Findings From Fisher Habitat Studies in British Columbia, Montana, Idaho, Oregon, and California. USDI Bureau of Land Management, Denver, Colorado, USA. 117pp.
  • Mazzoni, A. 2002. Habitat use by fishers (Martes pennanti) in the southern Sierra Nevada, California. M.S. Thesis. California State University, Fresno, CA.
  • Naney, R. H., L. L Finley, E. C. Lofroth, P. J. Happe, A. L. Krause, C. M. Raley, R. L. Truex, L. J. Hale, J. M. Higley, A. D. Kosic, J. C. Lewis, S. A. Livingston, D. C. Macfarlane, A. M. Myers, and J. S. Yaeger. 2012. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California–Volume III: Threat Assessment. USDI Bureau of Land Management, Denver, Colorado, USA. 55pp.
  • North, M., P. Stine, K. O’Hara, W. Zielinski, and S. Stephens. 2009. An ecosystem management strategy for Sierran mixed conifer forests. General technical report PSW-GTR-220. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 49 pages.
  • Naney, R. H., L. L Finley, E. C. Lofroth, P. J. Happe, A. L. Krause, C. M. Raley, R. L. Truex, L. J. Hale, J. M. Higley, A. D. Kosic, J. C. Lewis, S. A. Livingston, D. C. Macfarlane, A. M. Myers, and J. S. Yaeger. 2012. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California–Volume III: Threat Assessment. USDI Bureau of Land Management, Denver, Colorado, USA. 55pp.
  • North, M., P. Stine, K. O’Hara, W. Zielinski, and S. Stephens. 2009. An ecosystem management strategy for Sierran mixed conifer forests. General technical report PSW-GTR-220. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 49 pages.
  • Powell RA. 1993. The fisher: life history, ecology and behavior. 2nd ed. Minneapolis: University of Minnesota Press.
  • Spencer, W.D., H.L. Rustigian, R.M. Scheller, A. Syphard, J. Strittholt, and B. Ward. 2008. Baseline evaluation of fisher habitat and population status, and effects of fires and fuels management on fishers in the southern Sierra Nevada. Unpublished report for USDA Forest Service, Pacific Southwest Region. Conservation Biology Institute. Corvallis, OR. 133 pp + appendices.
  • Spencer, W.D., H. Rustigian-Romsos, J. Strittholt, R. Scheller, W. Zielinski, and R. Truex. 2011. Using occupancy and population models to assess habitat conservation opportunities for an isolated carnivore population. Biological Conservation 144: 788-803.
  • Spencer, W. and H. Rustigian-Romsos. 2012. Decision-support maps and recommendations for conserving rare carnivores in the interior mountains of California. Unpublished report for Sierra Forest Legacy. 37pp.
  • Thompson, C., K. Purcell, J. Garner and R. Green. 2009. Kings River Fisher Project. Two-year preliminary progress report presented to the Western Section of The Wildlife Society meeting, January 21-23, 2009. Sacramento, California.
  • Truex, R.L. W.J. Zielinski, J.S. Bolis, and J.M. Tucker. 2009. Fisher population monitoring in the southern Sierra Nevada, 2002 – 2008. Paper presented at the 5th International Martes Symposium, Seattle, WA. September 8–12, 2009.
  • Tucker, J.M., M.K. Schwartz, K.L. Pilgrim, and F.W. Allendorf. 2012. Historical and contemporary DNA indicate fisher decline and isolation occurred prior to the European settlement of California. PLoS ONE 7(12): e52803. doi: 10.1371/journal.pone.0052803
  • USDA Forest Service. 2006. Sierra Nevada forest plan accomplishment monitoring report for 2005. USDA Forest Service, Pacific Southwest Region R5-MR-000. 12pp.
  • Weir, R.D. 2003. Status of the fisher in British Columbia. British Columbia Ministry of Sustainable Resource Management, Conservation Data Center, and the Ministry of Water, Land, and Air Protection, Biodiversity Branch. Victoria, British Columbia, Canada.
  • Zielinski, W.J., R.L. Truex, C.V. Ogan, and K.Busse.1997. Detection surveys for fishers and American martens in California, 1989-1994: Summary and interpretations. Pages 372-392. In G. Proulx, H.N. Bryant, and P.M. Woodard, editors. Martes: taxonomy, ecology, techniques and management. Provincial Museum of Alberta, Alberta, Canada.
  • Zielinski, W.J., R.L. Truex, G.A. Schmidt, F.V. Schlexer, K.N. Schmidt, and R.H. Barrett. 2004a. Resting habitat selection by fishers in California. J. Wildl. Mngt. 68(3):475-492.
  • Zielinski, W.J., R.L. Truex, G.A. Schmidt, F.V. Schlexer, K.N. Schmidt, and R.H. Barrett. 2004b. Home range characteristics of fishers in California. J. Mammalogy, 85(4):649–657.
  • Zielinski, W.J., R.L. Truex, R. Schlexer, L.A. Campbell, and C. Carroll. 2005. Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California. J. Biogeog. 32:1385-1407.
  • Zielinski, W.J, R.L. Truex, J.R. Dunk and T. Gaman. 2006. Using forest inventory data to assess fisher resting habitat suitability in California. Ecological Applications 16:1010-1025.

[snapshot: 4/9/2013 @0936]




Bond et al. 2009, in a radiotelemetry study, found that California spotted owls preferentially selected high-severity fire areas (which had not been salvage logged) for foraging. In addition, Lee et al. 2012 found that mixed-severity wildland fire, averaging 32% high-severity fire effects, did not decrease California spotted owl territory occupancy, but post-fire salvage logging appeared to adversely affect occupancy.



Bio-Region Riparian Ecosystems

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF
Sierra Nevada Bio-region
Chapter 1: Ecological Integrity of Ecosystems - Riparian Ecosystems
Riparian Meadow and Riparian Non-Meadow Ecological Integrity

Current Condition

Introduction

Ch1_Riparian_Introduction_1-small.png

Riparian meadow and riparian non-meadow ecosystems border or straddle water bodies including streams, rivers, ponds, lakes, and seeps or springs. As a result, these areas support plants and animals adapted to wet environments. These riparian zones link terrestrial and aquatic systems. They play important roles in the landscape both for habitat and water and nutrient cycling. Transfers of nutrients, sediment, and coarse organic matter (leaves to logs, and contaminants between aquatic and riparian zones affect both systems. Riparian areas filter sediments and nutrients, and store water in alluvial soils that may prolong or sustain stream flow later in the summer (Yarnell et al. 2010).

Two distinct riparian ecosystems can be differentiated; 1) riparian meadow systems; and 2) riparian non-meadow systems (Fites-Kaufmann et al. 2007). They have different species composition, structure, and in some ways function. Riparian meadow systems are dominated by herbaceous vegetation, grasses, grasslike species, such as sedges or rushes, and often mosses and ferns (Weixelman et al. 2011). Riparian meadow settings generally have finer textured soils and better water holding capacity (WHC) (Potter 2005). Riparian non meadow areas include both woody species of shrubs and trees, as well as herbaceous grasses, grasslike species, mosses, and ferns. These riparian non-meadow settings generally have shallower soils, occur on steeper slopes, have higher coarse fragments (rocks) in the soils, and lower WHC (Potter 2005).

Most animal species in the region use both riparian meadow and riparian non meadow areas, at least seasonally, and some require these areas for breeding or their sole habitat. The emphasis of this section is on the vegetation, soils, and to a lesser degree hydrology in riparian ecosystems.

Riparian meadow and non-meadow plant communities are formed by the interacting effects of flood frequency and intensity, soil saturation and depth of water table, proximity to the channel, height above water level, sediment deposition, and ice scouring. In turn, these factors are controlled by flow levels, sediment availability, channel structure and substrate, channel erosion, and channel meandering which produces backwaters, old channels and different flow gradients and areas of deposition. Local factors determining the dominant species on a site include duration of soil saturation, soil depth, soil texture, flood frequency, season and duration, water table depth, degree of ice scouring, soil oxygen availability, browsing, grazing, and fire (Knight 1994, Weixelman et al. 2011). Changes in plant community composition are driven by successional processes in response to disturbance and simultaneously by changes in flooding regime and water table, all of which can change the site type and the potential plant communities that can form. Changes in stream gradient, sinuosity, channel width-to-depth ratios, topography and floodplain landform, and soil type (Knight 1994:43) driven by stream narrowing/widening, meandering/ channelization, and scouring/deposition produce various riparian landforms and resulting vegetation communities (Friedman et al. 1997). Vegetation composition is altered below dams due to changes in magnitude, duration, and frequency of flow levels below these structures.

Three photos showing riparian stream ecosystems for three different stream gradients: (a) low gradient, < 2%; (b) middle gradient, 2-4%; and (c) high gradient, > 4%
Ch1_Riparian_Fig01a.pngCh1_Riparian_Fig01b.pngCh1_Riparian_Fig01c.png

.Understanding these complex dynamics between hydrology, vegetation, soils, and wildlife is an ongoing effort. A conceptual model depicting the structure and functioning of riparian and meadow ecosystems is useful to summarize what we understand at this time, figure below. Shown in the model in Figure 2 are key ecosystem attributes which affect the structure and functioning of riparian meadow and non-meadow ecosystems. Major ecosystem attributes which affect riparian structure and function are soil, terrestrial invertebrates, terrestrial vertebrates including livestock, climate, upland watershed characteristics, and streamflow regime. General patterns of influence for each of these major ecosystem attributes on riparian systems is shown in Figure 2 as well as interrelationships between major ecosystem attributes affecting the riparian ecosystem.

General conceptual model depicting the structure and functioning of riparian meadow and non-meadow ecosystems. Symbols represent the following: rectangles = biotic components; ellipses = state factors or major drivers of ecosystem change or variability. Arrows indicate functional relationships among components. The model is constrained by climatic conditions, topography, parent material, and potential biota (adapted from Chapin et al. 1996)
Ch1_Riparian_Fig02.png



Current Condition


Riparian non-meadow ecosystems


Riparian non meadow areas include those areas where woody plant species are dominant over herbaceous species in the riparian zone. Condition of riparian non-meadow areas, like other riparian areas, is determined by functional and structural characteristics. Condition of these non-meadow riparian areas is often summarized by comparing existing tree densities, stand age class distribution, and understory composition with historical or “natural” conditions. Potter (2005) described major non-meadow vegetation types and characteristic soils for the Southern Sierra Nevada. Potter classified a number riparian non-meadow plant communities including those dominated by aspen (Populus tremuloides), willow (Salix spp.) lodgepole pine (Pinus contorta), Ponderosa pine (Pinus ponderosa), and alder (Alnus incana) with considerable variation within types. In addition to variation within individual types, riparian non-meadow ecosystem types are arranged across the landscape in patchy, spatially complex patterns. This results primarily from the interactions of elevation, hydrogeomorphic surface, and fluvial disturbance, and leads to stands that are relatively small (Potter 2005). There is little data available on the ecological condition of non-meadow riparian areas in the Sierra Nevada and the Southern Cascade ranges. The data that does exist is primarily concerned with structural characteristics such as overstory stem densities, fuel loading, and stream flow characteristics.

Because riparian non meadow areas are dominated by trees and/or shrubs, structural characteristics are an important aspect of their function. Structural characteristics that are important in riparian systems include the proportion of conifer to hardwood cover, canopy layering, canopy cover, and bare ground.

Dams and diversions, climate change, fire, concentrated recreation use, vegetation management, and grazing can all affect the structure, composition, and function of riparian areas. Little information exists on how most of these activities have affected riparian ecosystem Kattelmann and Embury 1996). Most information is available on modifications from water development and the effects of fire suppression. Stream flow characteristics have been locally modified by dams which alter the timing, duration, and frequency of flood events.
Fire plays an important role in shaping many Sierran riparian non meadow tree and shrub riparian ecoystems van Wagtendonk and Fites-Kaufman 2006) but longer fire return intervals and reductions in area burned have altered these communities (Van de Water and North 2011). Productive, mesic riparian forests can accumulate high stem densities and fuel loads, making them susceptible to high-severity fire. Fuels treatments applied to upland forests, however, are often excluded from riparian areas due to concerns about degrading streamside and aquatic habitat and water quality.

Van de Water and North (2011) found that under current conditions, riparian forests were significantly more fire prone than upland forests, with greater stand density (635 vs. 401 stems/ha), probability of torching (0.45 vs. 0.22), predicted mortality (31% vs. 16% BA), and lower quadratic mean diameter (46 vs. 55 cm), canopy base height (6.7 vs. 9.4 m), and frequency of fire tolerant species (13% vs. 36% BA). Under current conditions the modeled severity was much greater in riparian forests, suggesting forest habitat and ecosystem function may be more severely impacted by wildfire than in upland forests (Van de Water and North 2011). However, this study used 97th percentile fuel moisture and weather conditions (i.e., the most extreme fire weather) to model potential fire behavior and even under those circumstances found only 31% predicted mortality, which is associated with low/moderate severity fire.

Condition of riparian non meadow areas has been affected in certain areas by dams. Dams and water diversions can heavily modify the volume of water flowing downstream, change the timing, frequency, and duration of high and low flows, and alter the natural rates at which rivers rise and fall during runoff events. Although much has been written about the ecological consequences of hydrologic alteration, Bunn and Arthington (2002) summarize their review of this literature by highlighting four primary ecological impacts associated with flow alteration: (1) because river flow shapes physical habitats such as riffles, pools, and bars in rivers and floodplains, and thereby determines biotic composition, flow alteration can lead to severely modified channel and floodplain habitats; (2) aquatic species have evolved life history strategies, such as their timing of reproduction, in direct response to natural flow regimes, which can be de-synchronized through flow alteration; (3) many species are highly dependent upon lateral and longitudinal hydraulic connectivity, which can be broken through flow alteration; and (4) the invasion of exotic and introduced species in river systems can be facilitated by flow alteration.

Summary of riparian existing conditions in relation to the riparian natural range of variability (NRV)
  • Most available accounts indicate a major decrease in area of riparian vegetation in the assessment area since European colonization. As of 1988 less than 2%, of the Sacramento River’s Riparian forest is estimated to remain (Spotts 1988) and riparian vegetation currently makes up less than 1% of the Sierra Nevada bioregion area (Kattelmann & Embury 1996).
  • Late 19th century timber harvest had disproportionate impacts on riparian forests both because rivers and drainages were frequently used to transport harvested logs and because gold-mining activities were focused within streams and required wood (Kattelmann & Embury 1996).
  • Many historic riparian sites are now under water, as wide valleys with large swaths of riparian habitat offered ideal reservoir locations (Kattelmann & Embury 1996).
  • In areas where water flow has been completely or nearly eliminated due to water development riparian vegetation has nearly disappeared (Kattelmann & Embury 1996; Stine et al. 1984).
  • Riparian zones are at greater risk of fragmentation, and non-native species invasion, than historically.
  • 93% of studied watersheds in the assessment area have clear gaps in the riparian corridor – largely from road/railroad crossings, timber harvest, private lot clearing, livestock grazing, and dam/diversion dewatering (Kondolf et al. 1996).
  • Riparian zones are among those areas of the Sierra Nevada most impacted by non-native invasive species (Schwartz et al 1996), and altered riparian systems may be especially vulnerable (Parks et al. 2005).
  • Current riparian forests are more fire prone than reconstructed historic riparian forests, including great basal area, stand density and snag volume, duff and total fuel loads, predicted surface and crown flame lengths, probability of torching, and predicted post-fire tree mortality (Van de Water & North 2011).
  • Fire plays an important role in shaping riparian communities (Russell & McBride 2001), but fuel management has been prohibited in riparian corridors due to concern for water quality and sensitive riparian ecosystems (Kobziar & McBride 2006). Fire return interval (FRI) was found to be shorter for riparian zones which bordered narrower, more incised streams, where FRI and fire severity may mirror upland characteristics (Van de Water & North 2010). Larger, extended, less steep riparian zones, other the other hand, may act as natural fire breaks (Kobziar & McBride, 2006; Van de Water & North 2010).
  • Major changes in flow regimes, a key shaping force of riparian communities, have led to significant differences between current and historic conditions in riparian zones.
  • Currently, droughts in the Sierra Nevada usually last less than a decade. The drought record suggests that that multidecadal and even multicentennial droughts (low flow regimes) would be expected under the natural range of variation (Benson et al. 2002).
  • In many regions of the assessment area, natural flow regimes have been so compromised by water development (e.g. diversion, exportation, inter-basin transfers), that discussion of current ‘natural’ flow regimes is limited in applicability (Elmore et al. 2003). For example, water diversion from the Truckee River led to a decrease in depth of Pyramid Lake in the 1960s greater than the estimated effects one of the most severe droughts of the previous 2,000 years (Benson et al. 2002).
  • More generally, water development throughout the assessment region has reduced flow seasonality and shifted flow peak timing, reducing spring flood pulses and augmenting summer flow (Vaghti & Greco 2007). The resulting lack of episodic disturbance and increased summer water levels have led to shifts in riparian species recruitment and survival (Vaghti & Greco 2007).
  • Over the last century, climate change has caused discernible shifts in factors causing debris flows in the montane areas of Western United States, including: more winter precipitation falling as rain instead of snow, leading to increased spring flow (Barnett et al. 2008); increased frequency of catastrophic floods due to rain-on-snow events (Herbst & Cooper 2010); and increased melting of alpine glacier cover (31-78% in the Sierra Nevada; Basagic & Fountain 2011).
  • Riparian communities contain more plant and animal species than any other California community type (Schoenherr 1992) and about one fifth of terrestrial vertebrate species in the Sierra Nevada depend on riparian habitat (Kattelmann & Embury 1996). About one quarter of wildlife species that depend on riparian habitat are considered at risk of extinction today (Graber 1996; Kattelmann & Embury 1996).
  • Surveys the lower Truckee River in 1981 revealed that only 1 of the 21 obligate riparian bird species had not shown strong declines in population since 1868 (Rood et al. 2003). As of the mid 1990s, half of the 32 amphibian species and almost half of the 40 fish species/subspecies found in the Sierra Nevada were endgangered, threatened, or of special concern (Moyle et al. 1996). Additionally, 85% of Sierra Nevada watersheds are characterized by poor to fair aquatic biotic communities (Moyle & Randall 1996).

Common terrestrial measures of riparian meadow function based on vegetation and physical attributes.
Indicator
Measure
Source
Meadow vegetation condition
Abundance of different plant functional groups; diversity index
USFS Region 5 Range Monitoring Program, USDA NRCS (1975), National Research Council (NRC) 1994
Non-native species
Abundance
USFS Region 5 Range Monitoring Program
Streambank vegetation condition
Abundance of different plant functional groups
USFS Region 5 Range Monitoring Program
Soil characteristics
Amount of bare soil in meadows
Fryjoff-Hung & Viers, 2012. Sierra Nevada Multi-Source Meadow Polygons Compilation, USFS Region 5 Range Monitoring Program
Connectivity of stream to floodplain
Stream incision
Fryjoff-Hung & Viers, 2012. Sierra Nevada Multi-Source Meadow Polygons Compilation, Stillwater Sciences. 2012
Conifer encroachment in meadows
Abundance of conifer cover in meadow
Fryjoff-Hung & Viers, 2012. Sierra Nevada Multi-Source Meadow Polygons Compilation

Riparian meadow ecosystems

Riparian meadow areas are those riparian areas where herbaceous plant species are dominant over woody species. Riparian meadow areas occur on a variety of landforms and receive water from various sources including precipitation, surface water inputs, or groundwater inputs (Weixelman et al. 2011). Riparian meadow areas occur on fourteen distinct hydrologic and landform (hydro-geomorphic) combinations in the Sierra Nevada and Southern Cascade ranges in CA (Weixelman et al. 2011). Riparian meadow sites occur along streamsides in valleys with varying gradients , along borders of lakes or depressions, and on hillslopes associated with flowing water. These sites are dominated primarily by sedges including Nebraska sedge (Carex nebrascensis), and beaked sedge (Carex utriculata), grasses including tufted hairgrass (Deschampsia cespitosa), and redtop (Agrostis stolonifera), rushes including Baltic rush (Juncus arcticus), forbs including western aster (Aster occidentalis), and yarrow (Achillea millefolium). Lodgepole pine (Pinus contorta), willow (Salix spp.), alder (Alnus spp.), or current (Ribes spp.) may be present but are not dominant. This section will focus on low and middle gradient riparian meadow systems (0 to 4% slope)(Weixelman et al. 2011). These areas are among the most intensely used by recreationists and livestock grazing.

The ecological integrity of riparian meadow systems can be summarized by important indicators listed in Table 1. The measures listed in Table 1 are terrestrial variables that are commonly measured in riparian and meadow ecosystems to provide information on ecological integrity. An important key indicator is the presence and extent of non-native plants which indicate the extent of meadow degradation, or health/integrity. The other side of this indicator is the diversity index for the presence of a suite of typical Sierra meadow plant species. Meadow and streambank condition provides information on the ability of vegetation to stabilize streambanks (Winward 2000), slow floodwater and catch sediment (Stillwater Sciences 2008), cycle nutrients for plant growth, and provide for infiltration and water storage (Weixelman and Zamudio 2001). The amount of incision provides information on the connectivity of riparian and meadow areas to the stream, overbank flooding and recharge along channel boundaries (Weixelman et al. 2011), water storage in the adjacent riparian (Yarnell et al. 2010), and accumulation of organic material in the soil. Information on encroachment of conifers relates to water table depths, fire regime, disturbance, and climate change influences. Finally, data on the amount of bare soil provides information on soil stability (Weixelman and Zamudio 2001).

Meadow condition


Weixelman and Zamudio (2001) devised an integrated measure of meadow ecological condition based on soil and vegetation composition and structure. Based on this study, meadow condition can be shown graphically as in Figure 3. Four condition classes are shown in this graphic; early seral, mid seral, late seral, and potential natural vegetation (PNV). The four condition classes represent ecological health from low (early seral) to high (potential natural vegetation). At the early seral stage there is a high amount of disturbance resulting in an abundance of early successional plant species (Mosley et al. 1986), shallow rooting depths, and generally high amounts of bare soil (Weixelman and Zamudio 2001). Rooting depth is defined as the maximum depth of at least 1 root per square cm in the soil. This is the rooting density that is typical of later successional meadow plant communities (Weixelman and Zamudio 2001). At late seral and PNV, late seral species are dominant, rooting depths are deep, and there is very little bare soil. Late seral and PNV condition classes represent a desirable condition because there are ample amounts of late successional plant species for community resilience, greater plant diversity than lower condition sites (Weixelman and Gross, unpublished to be submitted spring 2013), and deep rooting depths to maintain soil stability and streambank protection.

Monitoring plots have been established for key area meadows under the Region 5 Range Long Term Monitoring Project. These plots are used to monitor rangeland condition and trend and the plots are re-read on a 5 year cycle. The plot locations are non-randomly selected and are located in areas within the meadow most likely to show change and transition. Specifically, the plots are located in mesic sites (moist meadow type) that are likely in a lower ecological condition as opposed to being placed in the hydric or wetter types that are more likely to be at good ecological condition. Therefore the plots are established to best determine changes such as fluctuations in species composition, over time. Since the monitoring sites were selected to best represent trend, they do not necessarily reflect the overall condition of an area. Condition in the wetter area may not be the same as in a drier area of the meadow. Key areas were selected within the meadows so that when the range types on these sites are at desired condition, or trending towards desired condition at a satisfactory rate, surround types will likely be trending the same.

Graphical representation of riparian meadow condition. Four condition classes are identified: early seral, mid seral, late seral, and potential natural vegetation, PNV (National Research Council, 1994).

Chap1_Rip_06.jpg

Riparian meadow condition for the Sierra Nevada and Southern Cascades in CA


Meadow Key Sites

Using the four condition classes above, the condition of 505 meadow sites in the Sierra Nevada and Southern Cascades is graphically shown in Figure 4 based on results from the R5 long term monitoring of key sites. A wetland index on the vertical scale (Gross et al. 2013) indicates the type of meadow, whether wet, mesic, or dry. This index represents the proportion of plants that are wetland indicators, the larger the number, the higher the proportion of wetland indicators. The horizontal axis represents a functional index (from Gross et al. 2013) from zero to 100. The functional index is determined by the proportion of plant functional groups (Weixelman and Gross, to be submitted in spring, 2013) on a meadow site. Desired condition is represented by the late seral and potential natural vegetation condition classes (Weixelman 2013). The graph indicates that most of the meadows sampled were in the mesic or wet meadow type. The data represent the latest reading for each of the sites.


Graph of condition for 505 meadow sites in the Sierra Nevada and Southern Cascade ranges in California (from USFS R5 Long Term Monitoring Report, Weixelman 2013). Graph design adapted from Gross et al. (to be submitted, spring 2013). Sites shown are the long term monitoring plots established by the Forest Service range crews. Plots were established at key monitoring sites from 1999 to 2004. These plots are revisited every 5 years and continue to be visited. Condition increases from 0 to 100. Condition classes (0-25, 26-50, 51-75, 76-100) taken from National Research Council, 1994).
Chap1_Rip_07.jpg

Random Meadow Sites


During 2001 and 2002, meadows were randomly chosen and sampled as part of the Sierra Nevada Framework Monitoring Program. During that time, 119 meadows were sampled to represent the condition of meadows across the Sierra Nevada and Southern Cascades. Figure 5 shows the condition of those meadows that were sampled. Unlike the sampling protocol above used for range monitoring, the sampling protocol used in the Framework monitoring consisted of transects placed across the entire meadow, thus giving an “average” condition for the entire meadow complex. As in the graph above, meadow condition is shown using a functional matrix adapted from Gross et al. (2013). A wetland index is shown on the vertical axis (see above) and a functional index is shown on the horizontal axis. The condition of these 119 sites show that wetter meadows were generally in higher condition than were dry meadows. In addition, as above, more wet and moist meadows were sampled than were dry meadows. The proportion of sites meeting or exceeding desired conditions is similar to the results for the range key site monitoring shown below.

Graph of condition for 119 meadow sites in the Sierra Nevada and Southern Cascade ranges in California (from USFS R5 Framework Monitoring, 2001 - 2002). Graph design adapted from Gross et al. (to be submitted, spring 2013). Sites shown are randomly sampled sites established in 2001 and 2002. Four condition classes are shown, early seral, mid seral, late seral, and potential natural vegetation (PNV). Condition classes taken from National Research Council, 1994). Desired conditions are late seral and PNV.

Chapter3_Water_11.jpg
Ecological Integrity and Natural Range of Variability for Meadows
At this point, the range of natural variability (NRV) for meadow areas has not been determined for the Sierra Nevada and Southern Cascades and has been estimated based on areas that have been ungrazed (including exclosures) for 20 to 30+ years (Weixelman and Zamudio XXXX) and analyses of meadow ecological integrity have been based on these results. To further refine estimates of the NRV for meadows, a study will be undertaken starting in summer, 2013, and extend through 2014. This study will involve sampling approximately 120 meadows in the National Park system in the Sierra Nevada and Southern Cascade ranges. This sampling will allow the Forest Service to estimate the NRV condition for meadows and provide information on distribution of meadows successional stages that can be expected across the landscape under conditions approximating the NRV. This assessment of meadow NRV will use the scoring system outlined in Gross et al. (unpublished, to be submitted spring 2013) and the plant ratings for indicating ecological integrity outlined in Weixelman and Gross (unpublished, to be submitted spring 2013) to assess the ecological integrity of the sampled meadows in the National Park System. This will provide a direct comparison to meadows and land disturbing impacts on Forest Service lands with meadow NRV.

Streambank vegetation condition in meadows
The kind, amount, and location of vegetation are crucial to the function of most riparian systems. Greenline (streambank) monitoring measures the vegetation along the edge of streams. This method samples plant community type composition on both sides of the stream in a selected section of a stream (within one riparian vegetation complex) and compares the composition with objectives for the area as well as past measurements. Objectives may be based on a “standard” required for proper functioning of that particular stream type. Winward (2000) suggests the standard and rates each community type’s ability to buffer the forces of moving water. Greenline data can be used to develop a rating of both ecological status (i.e. the kind and amount of existing vegetation on that particular section of stream in relation to the amount and kind of vegetation that might potentially occur on that stream section) and average physical strength for buffering the effects of moving water (streambank stability rating). Greenline data as the same location through time can be used to evaluate long-term trend.


Ecological integrity of streambanks gives an indication of the stability of the streambank system in a meadow and susceptibility to streambank failure. Streambank failure can result in stream widening, incision, or both. The greenline method of Winward (2000) was used to assess the ecological integrity (condition) of streambank vegetation in meadows for grazed allotments in Region 5. A total 155 permanent monitoring sites for streambank vegetation have been established in Region 5 and these sites are monitored every five years. These monitoring sites were established from 1999 to 2004 using the greenline method. Successional stages are used to summarize the greenline method (Winward 2000). The early successional stages are considered lower ecological condition, while the late successional stages and PNC (Potential Natural Community) are considered high ecological condition. The greenline is a measure of the percent of late successional plant communities on the streambank (greenline) along a lineal stretch of 364 ft. of streambank. The figure below summarizes the results and represent the latest readings taken during the period 2004 to 20111. Desired conditions for these sites are late seral or PNC (Potential Natural Community). The data represent the latest reading for each of the sites.

A summary of results for streambank vegetation data in low and middle gradient riparian meadow types for eight National Forests (from Weixelman 2013).

Chap1_Rip_08.jpg


Incision depths for stream channels in meadows in the Sierra Nevada and Southern Cascade ranges

Stream incision occurs when a streambed downcuts (degrades) in elevation (Simon and Rinaldi 2006). Incision is a common response of alluvial channels that have been disturbed such that they contain excess amounts of flow energy or stream power relative to the sediment load (Simon and Rinaldi 2006). One way in which changes in streambed elevation relative to floodplain elevation can lead to cascading effects on adjacent ecosystems is by impacting soil water availability. An incising streambed leads to a lower stream surface elevation, which then leads to a reduction in the water table elevation. A lower water table results in reduced water availability in the root zone and, typically, a transition to plant communities more adapted to dry conditions. Many examples of this phenomenon exist in the wet meadows of the Sierra Nevada and southern Cascade ranges in California, USA (Loheide et al. 2009).

The causes of the channel incision include changes to the streamflow regime, overgrazing, mining activities, road/railroad construction and channelization/drainage activities. Increased peak stream discharge has mostly been a consequence of changes in land use following Euro-American settlement in the mid-1800s (Loheide et al. 2009) but may also be related to changes in climate (Germanowski and Miller 2004). Overgrazing by sheep and cattle was very common throughout the Sierra Nevada prior to 1930 (SNEP 1996) and led to direct mechanical action of hooves on the stream bed and banks as well as compaction of soil in the uplands, reduced infiltration rates, and increased surface runoff (Trimble and Mendel 1995). In addition to the effects of grazing, timber harvesting played a role in increasing the magnitude of the hydrologic response through increased surface runoff and decreased surface roughness. The other direct cause of channel incision – stream channelization – was also common across the region. Some channelization projects were intentionally constructed to drain wet meadows to allow for railways, roads, homes, and agriculture; other projects related to railway/road construction or crossings inadvertently led to channel degradation and wet meadow drainage (SNEP 1996).

When the stream bed incises, the stream stage and water table in the interconnected aquifer also decline, causing the near-surface soil water regime to become drier in the meadow. However this process does not occur uniformly across the valley. The slope of the water table increases as a consequence of incision and continued groundwater inputs to the valley from the hillslope. This results in more xeric (very dry) vegetation near the channel where the water table depth is greater as compared with near the hillslope where more mesic (moderate amount of moisture) vegetation is present.

During summer, 20010 and 2011, surveys were conducted to measure channel incision on 101 meadows on six National Forests in the Sierra Nevada and Southern Cascade ranges (Fryjoff-Hung & Viers, 2012). The results of the surveys are shown in Figure 6. The results are given as the amount (cm) of stream incision. Results were not available for the amount of incision using bank height ratio, i.e. the height of the bank relative to the depth of the stream. Bank height ratio is informative as it scales to the stream channel size. However, the results presented here are informative in giving a general summary of the depth of incision for wadeable streams in the Sierra Nevada and the potential loss of wet meadow. These results indicate that approximately 46 out of 101 (or 46%) of riparian meadows on six National Forests were not incised significantly, while 54% were significantly incised based on depth of incision.

Incision depth for 101 low and middle gradient riparian sites for six National Forests, Sierra Nevada and Southern Cascade ranges, CA (Fryjoff-Hung & Viers, 2012)
Chap1_Rip_02.jpg

Conifer cover in meadows

Conifer encroachment into montane meadows in the Pacific northwest and California Sierra Nevada has been reported by many authors (Vale 1981, Rochefort et al. 1994, and Taylor 1995, Griffiths et al. 2005). Since meadows are more diverse than adjacent forests, replacement of
meadow vegetation by conifer forest reduces local and landscape biodiversity (Haogo and Halpern 2007). In the central Sierra Nevada, including areas within and just south of the CABY region, encroachment occurs most commonly with lodgepole pine and to a lesser amount, red fir.
Western hemlock encroachment in meadows also occurs within the zone of this species (Taylor 1995). Conifer encroachment into mountain meadows has been attributed to several (nonexclusive) causes, including climate effects (Helms 1987 and Woodward et al. 1995, Millar et al. 2004), direct effects from grazing (Andersen & Baker, 2005; Franklin et al., 1971), cessation of grazing (Dunwiddie 1977, (Vale 1981, Miller and Halpern 1998), and fire suppression (Arno and Gruell 1986, Hadley 1999). It is possible that all of these factors allow for increased conifer cover in existing meadows. Millar and others (2004) recently published a study including 10 meadows experiencing conifer (lodgepole) invasion in the Central Sierra Nevada. Tree establishment dates were correlated to long-term fluctuations in weather patterns associated with climate change (Pacific Decadal Oscillations or PDO). Over 87% of the cored meadow trees were established within a single 30 year period (1945 to 1974), which coincided with negative PDO, associated with consistently drier weather and low soil moisture in the 20th Century. Thus, Millar et al. (2004), argue that conifer invasion in these meadows occurred during a single mid-20th Century pulse that was triggered by climatic conditions.

During summer, 20010 and 2011, surveys were conducted to measure the amount of conifer cover in 101 meadows on six National Forests in the Sierra Nevada and Southern Cascade ranges (Fryjoff-Hung & Viers, 2012). The results of the surveys are shown in Figure 7. The results are given as the percent cover of conifer trees in the meadow. Results indicate that approximately 27/101 or 27% of riparian low and middle gradient systems have little or no conifer cover (< 1%), while 40% have a conifer cover greater than 10%. While 12% of the sampled meadows had a conifer cover greater than 20%.


Amount of conifer cover on 100 meadows on 6 National Forests, Sierra Nevada and Southern Cascade ranges, CA.
Chap1_Rip_03.jpg



Photo of low gradient riparian area and meadow on the Plumas National Forest. Conifer encroachment is occurring on this meadow and restoration by cutting of conifers has been conducted (note tree stumps) (photo by D. Weixelman).
Chap1_Rip_04.jpg

Amount of bare ground in meadows

Bare ground--soil that is not covered by vegetation, litter or duff, downed woody material, or rocks--is highly susceptible to erosion. It may contribute both to overland sediment flow and to the erosion of streambanks. In both cases, it can affect water quality as well as the loss of valuable soil and acreage. Soil not covered by desirable vegetation is a prime area for invasion of noxious weeds or other undesirable plant species. Bare ground increases the possibility of compaction or bank shearing by hoofed animals, vehicles, or people. This reduces the water-holding capacity of the soil.

One of the difficulties in assessing this aspect of riparian health is that many riparian areas will naturally have bare soil and dry meadows naturally have more bare soil than wetter meadows. After high flow events, bare soil in the form of trapped sediment could indicate riparian vegetation on the site is performing its sediment-trapping function. On the other hand, such a situation could also reflect an unstable situation further upstream.
It is important to try to determine what caused the bare ground. If it is related to or caused by human activities or has been increased by management practices, it is more likely to indicate a deteriorating situation somewhere along the stream. Some human activities which can lead to increased bare ground are livestock mismanagement, poor road construction, or excessive ATV use.

The Forest Service considers bare ground in excess of 10% cover as an indication of significant degradation in wet and moist meadows on key range monitoring sites. In some cases, gopher activity can produce high amounts of bare ground in some meadows. Figure 9 summarizes the percent bare ground on 110 meadows on six National Forests in the Sierra Nevada and Southern Cascade ranges. Results indicate that approximately 81% of meadow sites in this survey have less than equal to 10% bare ground, while 19% have greater than 10% bare ground. A value of greater than 10% bare ground generally indicates that significant degradation has occurred in a meadow. The data represent the latest reading for each of the sites.


Amount of bare ground for 101 meadows on 6 National Forests, Sierra Nevada and Southern Cascade ranges, CA.

Chap1_Rip_05.jpg


Trend

In order to provide information on trends for condition of riparian meadows areas and to provide information on the relationship of managed grazing and the ecological integrity of meadows sytems, the Forest Service Pacific Southwest Region 5 has entered into a Challenge Cost Share Agreement with the University of California, Davis Rangeland Watershed Laboratory. This project was initiated to evaluate rangeland (meadow and upland) ecological integrity and trends in ecological integrity across grazing allotments in U.S. Forest Service (USFS) Region 5. As described above, the Forest Service Pacific Southwest Region 5 initiated a long-term, region-wide monitoring program to make field measurements of rangeland plant and soil indicators of ecological condition (Rangeland Long-Term Condition and Trend Monitoring Program). Over 800 monitoring sites have been established throughout the Region since 1999, with sites sampled/re-sampled every 5 years.

Dr. Kenneth Tate’s laboratory is currently collaborating with Region 5 to conduct statistical analysis of these data to determine ecological condition and trend condition, and correlate management to trends in condition.
Objectives of the study include the following:

Objective one: Statistically analyze, interpret and publish results on: 1) rangeland condition and trend for the over 400 sites enrolled in the Rangeland Long-Term Condition and Trend Monitoring Program -Term Meadow Monitoring Project which have 10 years of data; and 2) correlation of grazing management and standards and guidelines with rangeland condition and trend.

Objective two: Transfer the information developed from these analyses to USFS staff, grazing managers, and stakeholders to enhance range NEPA accomplishment, inform up-coming Forest Plan revisions, and to help identify restoration opportunities.

It is expected that when this information is available it will be included in the Forest Plan revision process. This study will provide a more meaningful assessment of trend and response to grazing management as well as to weather and other factors (i.e., elevation, initial meadow condition).

Riparian Fauna


Though less than 1% of the area of the Sierra Nevada is comprised of riparian habitat (Kattlemann and Embury 1996), approximately onefifth of the 400 species of terrestrial vertebrates that inhabit the Sierra Nevada are strongly dependent on riparian areas (Graber 1996).

Birds

Riparian areas are among the most important habitats for birds in the Sierra Nevada (Siegel and DeSante 1999, Burnett and Humple 2003, Burnett et al. 2005).

Meadows and birds

In the Sierra Nevada, riparian aspen and meadows support several rare and declining bird species and are utilized at some point during the year by almost every bird species that breeds in or migrates through the region (Siegel and DeSante 1999 ). Management and restoration of aspen and meadow habitats should consider the importance of the habitat to birds and other wildlife. A disproportionate number of the special status wildlife species in the Sierra Nevada are tied to meadows, including four bird species – Greater Sandhill Crane, Great Gray Owl, Willow Flycatcher, and Yellow Warbler. Using meadow and aspen associated meadow-dependent bird species (focal species) as indicators of aspen and meadow ecological function can be a powerful adaptive management tool for informing management and restoration decisions in Sierra Nevada (see //Managing Meadows for Birds in the Sierra Nevada//: http://www.prbo.org/calpif/plans.html). Through such a focal species approach, it is possible to identify conservation priorities, help guide meadow and aspen restoration design and management prescriptions, and establish and evaluate management and conservation targets (Burnett et al. 2005, Chase and Geupel 2005, Campos and Burnett 2012).

Aspen and birds

The health of aspen habitat across the West has deteriorated over a century of mismanagement. Estimates suggest its extent in western North America has been reduced by as much as 96%, primarily because of fire suppression and overgrazing. Aspen habitat, especially when associated with riparian vegetation, is the single most species-rich avian habitat in the Sierra Nevada. Several bird species of management interest are associated with aspen including Northern Goshawk, Red-breasted Sapsucker, Warbling Vireo, and Mountain Bluebird. With its disproportionate importance to birds and other wildlife, limited extent on the landscape, and significant loss and degradation, aspen restoration should be among the highest priorities of land managers in the Sierra Nevada. Strategies for enhancing aspen bird habitat include: (1) promoting aspen regeneration and expansion, (2) managing for multiple age and cover classes, (3) restoring riparian aspen communities, (4) managing for dense and diverse understory, (5) limiting grazing and over-browsing (see //Managing Aspen Habitat for Birds in the Sierra Nevada//: http:www.prbo.org/calpif/plans.html).

Bird species richness and abundance in aspen habitat in the Sierra Nevada are positively correlated with lower percent conifer cover and increased herbaceous cover (Richardson and Heath 2004). Aspen stand restoration through the removal of competing conifers works to promote the regeneration of aspen stands (Jones et al. 2005) and provide habitat for many aspen-associated bird species (Campos and Burnett 2012).

Willow Flycatcher

Once common throughout the western United States, the willow flycatcher (Empidonax traillii) has been extirpated from much of its range. In central California, this Neotropical migrant is limited to breeding in montane meadows. Surveys indicating a declining population trend led to the listing of the willow flycatcher as a California state endangered species, which prompted the initiation of a distribution and demographic study in 1997 (Mathewson et al. 2011). This research includes over 30 study sites (meadows) grouped into 3 regions: south (south of Lake Tahoe), central (north Lake Tahoe, Truckee meadows and vicinity), and north (Warner Valley south of Lassen Volcanic National Park). Primary objectives were to (1) determine the distribution of breeding willow flycatchers; (2) quantify reproductive success, recruitment, dispersal and survival of willow flycatchers in selected meadows; (3) examine factors influencing demographic patterns through associated graduate research projects; and (4) use the results to make management and restoration recommendations (Mathewson et al. 2011).

The willow flycatcher population in the central Sierra Nevada declined during the course of this 14-year monitoring study (Mathewson 2011). The study reported an apparent contraction of their range from south to north, in that populations in the South Tahoe region all but disappeared during the course of our 14-year study, likely resulting from initial small population size, stochastic weather events, and low reproduction that influenced dispersal dynamics. The population of flycatchers in the Truckee regions exhibited annual fluctuations around stability, but with an overall declining trend. The persistence of flycatchers in the Truckee region likely was facilitated by the proximity of large (>100 ha) meadows with suitable breeding habitat interspersed with smaller meadows.

Relative to populations of willow flycatchers in lower elevation and non-mountainous regions, flycatchers in the South Lake and Truckee regions are constrained by the amount of time available to nest within a season. The nestling period and early fledgling period, and thus the month of July and early August, is a critical period determining reproductive success for an individual flycatcher. Riparian shrub density at the territory scale and extent of meadow inundation by water were the most influential habitat components.

Mathewson et al. (2011) recommended a meadow restoration initiative through-out several meadows of the Sierra Nevada within the current range of the flycatcher and at adjacent sites that supported flycatchers in the recent past. Habitat restoration would likely enhance nest success and it is one action that we can take on the nesting grounds that has some potential to increase juvenile recruitment and adult survival. Second, the study recommends moving grazing out of meadows with breeding flycatchers until the end of August. Current management practices allow for grazing starting in mid-July but this is a sensitive period for flycatchers in determining nesting survival, re-nesting possibilities, and post-fledgling survival. Brown-headed cowbird control would be beneficial in the short-term at some of the meadows that support currently breeding flycatchers but that for long-term sustainability meadow restoration will buffer the negative effects of parasitism. Last, these populations required continued monitoring to determine the effectiveness of meadow restoration efforts.

Great Gray Owl

In, 2010, it was documented that Yosemite's great gray owl (Strix nebulosa Yosemitensis) as genetically distinct from the great gray owl in western North America (Strix nebulosa nebulosa) (Hull et al. 2010). In addition to genetic differences, behavioral differences appear to exist in the Yosemite subspecies. These include differences in migration patterns, prey preference, and nest site selection. Each of these genetic and behavioral characteristics indicates the Sierra Nevada population of great gray owls has been isolated from other populations for an extensive period of time.

Yosemite, today, is the southernmost range and last sanctuary of almost all of California's great gray owls, listed as California State Endangered Species. Researchers estimate there are only about 200 to 300 individuals in California, and about 65% of the state's population resides in Yosemite. Great gray owls nest in the middle elevations of the park where forests and meadows meet. They can be active at any time of the day or night, preferring to hunt in open meadows and clearings within the forest. In the winter, they move downslope to snow-free areas where they can more easily access their rodent prey.

Wintering habitat of the Great Gray Owl was recently studied by Jepson et al. (2011). Little information is available on the winter ecology of the small, geographically isolated, genetically-unique population of great gray owls (Strix nebulosa) in the central Sierra Nevada, California. This population is comprised of facultative, elevational winter migrants and access to winter habitat is an important component of their ecology. Winter observations and remotely sensed habitat variables were used in a study by Jepson et al. (2011) to inform a predictive model of the environmental requirements and geographic distribution of this owl population. Using the modeled distribution map, the assessed the distribution of 20% probability of occurrence classes relative to owl habitat associations, ownership, current development, and projected future development patterns. Findings indicated that high probability class (81–100%) areas and the broader joint medium/medium-high/high probability class (41–100%) areas are uncommon on the landscape (0.2% and 5.0% of study area, respectively). High probability areas were characterized by Sierran Yellow Pine forest surrounding relatively small, flat areas of grassland, wet meadow, and riparian habitats, within the mid-elevation range. Approximately 32% of the high probability areas and 48% of the medium/medium-high/high probability areas occur on private lands. Of the areas on private lands, 32% of the high probability and 42% of the medium/medium-high/high probability areas occur on currently developed lands. Projected future development on private lands indicated that an additional 12% of the high and 18% of medium/medium-high/high suitability areas are slated for development by the year 2040. The study concluded by saying that future conservation planning efforts for the great gray owl in the Sierra Nevada will need to address management issues on both public and private lands (Jepson et al. 2011).

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[snapshot: 4/9/2013 @0939]



Sierra NF

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF
Sierra National Forest
Chapter 1: Assessing Terrestrial Ecosystems, Aquatic Ecosystems, and Watersheds

Figures

Figure 1.1 Ecological sections of California showing context for Sierra National Forest
Figure 1.2 Ecological Subsections from Miles and Goudey (1997) overlain with the Sierra National Forest and the county boundaries
Figure 1.3 West facing foothill woodland dominated by blue oak and interior live oak above Big Creek, Fresno County, CA on April 5, 2009. (Sacate Ridge Research Natural Area, High Sierra Ranger District)
Figure 1.4 Montane mixed conifer forest near Nelder Grove; this stand is in a population of the Forest Service Sensitive lady’s slipper orchid (Cypripedium californicum)
Figure 1.5 Illustration of different habitats with subalpine habitat around portal lake in the foreground, alpine habitat on the ridge in the background. Photo by J. Clines
Figure 1.6 Subalpine meadow near Alstot Lake, Madera County. John Muir Wilderness. Photo J. Clines
Figure 1.7 Departure of the average Fire Return Interval (FRI) as compared with an average historical condition for Sierra National Forest, in percent
Figure 1.8 Wilderness areas within Sierra National Forest
Figure 1.9 Sierra National Forest wildlife habitats defined by the California Wildlife Habitat Relationship (CWHR) system
Figure 1.10 Vegetation canopy cover density in Sierra National Forest based on the California Wildlife Habitat Relationship (CWHR) habitat types
Figure 1.11 Vegetation size distribution in Sierra National Forest based on the California Wildlife Habitat Relationships (CWHR) habitat types

Tables

Table 1.1 Summary of ecological sections in the SNF. Displays subsections along with the designations of Miles and Goudey (1997) and identifies the characteristics of the vegetation of these broad zones, with special attention to features unique to the SNF
Table 1.2 Federally listed threatened, endangered, proposed and candidate wildlife species and Forest Service Sensitive species that are known to occur, or have the potential to occur within the Sierra National Forest
Table 1.3 Current Sierra National Forest wildlife habitats as defined by the California Wildlife Habitat Relationships (CWHR)
Table 1.4 Channel sensitivity and stability data

Landscape Setting


Overview

The Sierra National Forest encompasses 1.3 million acres (precisely 1,275,152 acres) of land and waters, with about 42 percent (528,000 acres) designated as Wilderness. The Forest is located along the west slope of the central-southern Sierra Nevada. Elevations range from 900 feet at Pine Flat Reservoir to nearly 14,000 feet at the summit of Mount Humphreys (13,986 feet) along the Sierra Crest. Climate generally consists of warm, dry summers and cool, moist winters at the lower elevations, with harsher winters as elevation increases. Mean annual precipitation is 20 to 60 inches with most falling as snow above about 5,000 feet elevation.
The enormous elevation span of over 12,000 feet, combined with the variability in aspect and slope created by three deep river canyons, a variety of geology and soils, and precipitation primarily as rain at low elevations and snow at high elevations, combine to create an extremely high diversity of ecosystems across the Forest. Indeed, the Sierra National Forest is inhabited by over 1400 taxa (species, subspecies, varieties), of vascular plants, about 300 species of bryophytes (mosses, hornworts, and liverworts), several hundred species each of lichens and fungi; and approximately 346 species of fish and wildlife: 31 fish species, 13 amphibian species, 198 bird species, 82 mammal species and 22 reptile species.

The Sierra National Forest’s geomorphic foundation primarily consists of an uplifted, westward-titled Sierra Nevada block that has been deeply incised by large rivers, such as the Merced, San Joaquin and Kings Rivers, as well as their tributaries. Bedrock is primarily granite, along with limited metamorphic and volcanic presence, as well as glacial deposition in the lower river valleys. Terrain is dominated by steep slopes and rocky canyons intermixed with low slopes and flat areas. Some areas of the Forest contain unusual rock types like limestone/marble and gabbro that create unique soil chemistry that support unique plant communities and often harbor rare plant species. For example, there is a relatively large vein of limestone in the Kaiser Wilderness in Fresno County, where unique plant species such as the rare moonwort ferns (Botrychium ascendens, B. crenulatum) are found at meadow edges. The metamorphic rock type (phyllite) found in the Merced River drainage contains the entire world distribution for two plant species: Congdon’s woolly sunflower (Eriophyllum congdonii)and the Merced clarkia (Clarkia lingulata).

Influences of Past Management

The Sierra National Forest has been largely affected by fire suppression for almost a century. As a result, live and dead fuels have increased to abnormally high levels of abundance, greater than the natural range of variability. However, it is important to keep in mind that forest areas that have missed the largest number of fire return intervals in California are burning predominantly at low/moderate-severity levels, and are not experiencing higher fire severity than areas that have missed fewer fire return intervals (Odion and Hanson, 2006, 2008, van Wagtendonk et al. 2012).

Historical logging, livestock grazing and residential development also have influenced current ecological conditions and management across the landscape. For example, prior to the mid-1900s, and to a less extent from the mid-1900s to the early-1990s, logging in Sierra National Forest, primarily within the lower and mid-slope areas (3,000 to 7,000 ft.), typically consisted of removing many of the largest overstory trees. This was particularly significant in what is now the Bass Lake Ranger District, as a result of extensive railroad logging between the late 1880s through the 1930s. These actions resulted in substantial reductions of sugar, ponderosa and Jeffery pine forests.

Late 19th century and early 20th century descriptions of the pre-European settlement mixed conifer and pine stands in the Sierra Nevada indicate that forest structures were dominated by uneven-aged tree distribution (Dunning, 1923; Show and Kotok, 1924). Dunning and Reineke (1933) remark, “In relatively few sections of this large region are the stands uniform in age…. Stands are usually made up of small even-aged groups, the ages of the groups differing by periods of 10 to 20 years.” The results of this past work in the early 1900s has shown that the historical forest, prior to the era of fire suppression, was composed of multiple age/size classes distributed in patches of varying sizes and shapes across the landscape (North et al. 2012). Research also shows that the historical forest was more open and comprised of widely spaced, large diameter trees (Sudworth, 1900; Stephens, 2001; Stephens and Elliott-Fisk, 1998; Stephenson and Calcarone, 1999). A majority of these trees were pine species with fewer shade tolerant, fire sensitive species, such as white fir and incense cedar found in stands subject to frequent fire (Minnich et al. 1995; Barbour et al. 2002). Reconstruction of historical forests in the Sierra Nevada showed that trees greater than 24 inches diameter at breast height (dbh) dominated Sierra Nevada forests (Taylor 2003). Reconstruction of ponderosa pine forests in the intermountain west (Arno and Scott 1995) also confirmed that large trees dominated those forests. Leiberg (1902), however, in addition to reporting that some areas were open and park-like (and dominated by ponderosa pine, Jeffrey pine, and sugar pine), also reported that other areas were dominated by white fir, incense-cedar, and Douglas-fir, especially on north-facing slopes and on lower slopes of subwatersheds; such areas were predominantly described as dense, often with “heavy underbrush” from past mixed-severity fire. (Leiberg 1902). Similarly, USDA Timber Survey Field Notes from 1910-1912 show that historic ponderosa pine and mixed-conifer forests of the central/southern Sierra Nevada [western slope] varied widely in stand density and composition; open and park-like pine-dominated stands comprised a significant portion of the lower montane and foothill zones, but dense stands dominated by fir and cedar, and by small/medium-sized trees, dominated much of the middle montane zone (it should be noted that the old-growth forests chosen for study by Scholl and Taylor 2010 and Collins et al. 2011 comprised only a very small portion of the 1910-1912 Stanislaus data set). (USDA 1910-1912).

The research on historic stand structure and composition supports the idea that selective logging and fire suppression have reduced the number of large trees, increased the density of smaller trees, and shifted composition toward shade tolerant fir and cedar. These past cumulative factors, combined with fire suppression since the 1920s, have reduced landscape-level ecosystem heterogeneity, as well as created abnormally high levels of fuel loads. This is particularly evident in current conditions with extensive areas dominated by shade-tolerant conifers, especially white fir and incense cedar. The extensive fire suppression, as well as limitations for mechanical forest restoration work during recent decades, also has reduced some meadow, oak and shrub habitat as a result of high coniferous tree density and tree encroachment. Overall, this loss of vegetation heterogeneity has detrimentally affected wildlife habitat diversity, as well as reducing ecosystem resilience affected by stressors, such as climate change. In particular, in regard to heterogeneity, there is likely a deficit of complex early seral forest on the landscape due to fire suppression, past and recent salvage logging, past and recent post-fire reforestation efforts, and past and recent mechanical treatments designed to prevent high-severity fires. Such early seral forest is created primarily by mixed-severity fire but even when such fire occurs, complex early seral forest will only exist when a) the pre-fire area contained elements necessary to create complex early-seral forest (e.g., dense mature forest versus plantations), and b) the post-fire area is not i) salvage logged or ii) reforested via human intervention. (See Chapter 1, Bioregion, "Complex Early Seral Forest").

During the last two decades, Sierra National Forest has made progress in improving and sustaining ecological heterogeneity within the natural range of variability. Some major actions include integrating more wildfire back into fire adapted ecosystems, retaining and developing large live and dead tree structures, and conducting tree thinning to develop and maintain forest heterogeneity, including forest canopy gaps and reducing tree encroachment into meadows and shrub patches (North et al. 2009, North ed. 2012). Although current management in the Sierra National Forest has made important strides toward integrating and sustaining ecological heterogeneity, additional restoration actions, adaptive management and research are needed to fully meet these ecosystem restoration goals.
Ecological Burning in the Sierra Nevada: Actions to Achieve Restoration

Terrestrial Ecosystems


Vegetation

The 12,000 foot elevation range of the forest is reflected in the high diversity of the vegetation. Broad vegetation zones can be seen going from west to east: foothill woodland and foothill chaparral in the low elevations at the western edge of the Forest (and extending up the river canyons) to ponderosa pine and mixed conifer forest at mid-elevations, to red fir/lodgepole pine forests even higher, to subalpine forests and treeless alpine vegetation at the highest elevations. Massive areas of rock outcrops (mostly granitic) occur throughout all of these vegetation types, as well as shrublands (chaparral) dominated by various species of oak, manzanita, and Ceanothus, and meadows, fens and riparian vegetation where moist conditions prevail. Herbaceous plant species contribute the most to species richness, either as understory species or as dominant members of plant communities such as meadows or grasslands. This existing condition description will use the Ecological Subregions of California, Section and Subsection Descriptions as a broad context for understanding the pattern of distribution of vegetation types in the Sierra National Forest (Miles and Goudey, 1997). Map 1 shows the Sections within California: the Sierra NF falls into Sections M261F and M261E. The Subsections will be shown and described next.

Figure 1.1—Ecological sections of California showing context for Sierra National Forest
Ch1_Sierra_Fig01.1.png
Figure 1.1—Ecological sections of California showing context for Sierra National Forest


The species diversity and number of different plant communities in the Sierra National Forest are both remarkably high, reflecting the variety of growing conditions resulting from differences in elevation, geology, moisture, temperature, soils, sunlight, slope, aspect, and disturbance regimes such as fire, avalanches, floods, and human activities. The native vegetation is also relatively intact compared to other parts of California (e.g. the central Valley, Southern California), with few to no non-native species at higher elevations.

Non-native plants make up a smaller proportion of all species in each major vegetation zone as elevation increases. An example from adjacent Yosemite National Park is given by Botti (2001), who wrote that 23 percent of plant species were non-native in the lower elevation chaparral/oak woodland zone of the Park, 13 percent of species in the mixed conifer zone were non-native, 5 percent of species in the upper montane zone were non-native, and only 0.5 percent were non-native in the subalpine zone. The alpine zone had no non-native species documented. This pattern appears true for neighboring lands in the Sierra National Forest as well. Extensive surveys of the high elevation wilderness over the past few decades have revealed very few non-native plants in the subalpine zone and no non-native species in the alpine zone.

As mentioned above, over 1400 vascular plant taxa have been documented to occur within the Sierra National Forest. Approximately 25 % of these are not native, and about 100 are so aggressive and damaging to ecosystems that they are classified as noxious weeds or invasive non-native plants (see Chapter 3). About 50 are so rare or face enough threats that they are maintained on the Regional Forester’s Sensitive Plant list, and one, the Mariposa pussypaws (Calyptridium pulchellum) is listed by the US Fish and Wildlife Service as Threatened. The Region 5 Sensitive Plant List is being revised in 2013, resulting in over 50 species being maintained as Forest Service Sensitive and about three species being removed from the list as they were found to be more common than previously thought. Chapter 5 provides details on these species at risk.

Figure 1.2—Ecological Subsections from Miles and Goudey (1997) overlain with the Sierra National Forest and the county boundaries
Ch1_Sierra_Fig01.2s.png
Figure 1.2—Ecological Subsections from Miles and Goudey (1997) overlain with the Sierra National Forest and the county boundaries


Table 1.1—Summary of ecological sections in the SNF. Displays subsections along with the designations of Miles and Goudey (1997) and identifies the characteristics of the vegetation of these broad zones, with special attention to features unique to the SNF

Ecological Section Number and Name (see Map 1)
Subsection Number
Subsection Name (See Map 2)
Unique features within the Sierra NF in this series
M261F – Sierra Nevada Foothills
M261Fc
Lower Granitic Foothills
Contains much of the blue-oak woodland in the Forest, about half of the rare tree anemone populations.
M261E – Sierra Nevada
M261Eg
Upper Foothills Metamorphic Belt
Metamorphic Paleozoic marine sedimentary rocks predominate. No ultramafic on the Forest in this region, though it is abundant adjacent. Chaparral dominated by chamise occurs in this part of the Forest. Knobcone pine occurs only within this belt. Many rare and endemic plants found here, including the Forest endemic Merced clarkia (State listed Threatened).
M261E – Sierra Nevada
M261Ep
Lower Batholith
Contains the remainder of the unique foothill chaparral that is lacking chamise and about half the rare tree anemone populations. Mixed conifer forest prevails at higher elevations. Contains Nelder Grove, one of the Forest’s 2 giant sequoia groves. The southern limit of Douglas fir in the Sierra Nevada occurs near Shaver Lake.
M261E – Sierra Nevada
M261Eq
Upper Batholith
Mixed conifer, upper montane coniferous forest, and subalpine forest, some in designated wilderness. Contains McKinley Grove of giant sequoias; the southernmost limit of douglas fir in the Sierra Nevada. This zone is rich in peatlands (fens) and meadows. The effects of past unregulated timber management, fire exclusion, and overstocking of livestock are particularly evident in this zone.
M261E – Sierra Nevada
M261Eo
Glaciated Batholith
Subalpine and Alpine zone, mostly in wilderness.

Foothill Zone

The foothill zone of the Sierra National Forest captures a small proportion of the western foothill belt which is mostly in private ownership throughout the Sierra Nevada. Because of this, the small amount of this biologically diverse vegetation type that is in public ownership is disproportionately important for long-term conservation (i.e. not subject to habitat loss from commercial and residential development).

This vegetation zone falls within Sierra Nevada Ecological Section M261F – Sierra Nevada Foothills – Subsection M261Fc (Lower Granitic Foothills) in the USDA Forest Service National Hierarchical Framework of Ecological Units and the lower part of Section M261Eg Sierra Nevada – Subsection M261Eg (Upper Foothills Metamorphic Belt) (Miles and Goudey, 1997) – See Table 1 above. Varying from gently rolling hills to nearly vertical, cliff-like slopes, this zone is characterized by a Mediterranean climate with long, hot summers, and cool, wet winters where most precipitation falls as rain (20-40 inches). Within the Sierra National Forest, as is typical for the Sierra foothills, the understory biomass is predominantly comprised of non-native plants while paradoxically native species diversity is higher than non-native species. This is primarily due to the presence of non-native annual grasses imported when Europeans arrived hundreds of years ago such as brome (Bromus spp.), wild barley (Hordeum sp.), wild oats (Avena spp.), and annual fescues (Festuca myuros) that form a continuous understory “blanket” while still allowing many natives to persist.

Tree-dominated plant communities are blue oak (Quercus douglasii) woodland or savannah, with foothill pine (Pinus sabiniana), California buckeye (Aesculus californicus), and interior live oak (Quercus wislizenii) present to varying degrees. Figure 1 shows open, southwest-facing slope with blue oak woodland on the north-facing slopes. Other tree-dominated types in the foothills are foothill pine and valley oak forests.


Figure 1.3—West facing foothill woodland dominated by blue oak and interior live oak above Big Creek, Fresno County, CA on April 5, 2009. (Sacate Ridge Research Natural Area, High Sierra Ranger District)
Ch1_Sierra_Fig01.3s.png
Figure 1.3—West facing foothill woodland dominated by blue oak and interior live oak above Big Creek, Fresno County, CA on April 5, 2009. (Sacate Ridge Research Natural Area, High Sierra Ranger District)


The Lower Granitic Foothills, Subsection M261Fc, is the primary Ecological Subsection of 261F within the Forest. This area of hot and sub humid climate and primarily granitic rocks is found on the Forest, north of the Kings River and encompasses part of the San Joaquin River watershed (Figure 1.1). The mixed chaparral found in this area and in the Lower Batholith (Subsection M261Ep) is unique to the Sierra National Forest: it is a diverse mixture of shrubs notably missing chamise (Adenostoma fasciculatum) which is an extremely common if not dominant shrub in chaparral elsewhere in California. Chamise exhibits an inexplicable gap from around the town of Oakhurst in Madera County south to Tulare County. It is not found in the San Joaquin or Kings River watersheds at all, but resumes its presence in the chaparral of the foothills in the Kaweah River Canyon; and is dominant in Mariposa County to the north in the Merced River Canyon.

The distinctive chaparral of eastern Fresno County is dominated by Mariposa manzanita (Arctostaphylos viscida ssp. mariposa), buckbrush (Ceanothus cuneatus), chaparral whitethorn (C. leucodermis), interior live oak (Quercus wislizenii), birchleaf mountain mahogany (Cercocarpus betuloides), western redbud (Cercis occidentalis), flannelbush (Fremontodendron californicum), and yerba santa (Eriodictyon californicum) with many other species adding to a highly diverse and special type of chaparral found only here. The relictual endemic shrub tree anemone (Carpenteria californica) has its natural range in the Sierra NF in this chaparral type, within about a 225 square mile area.

Montane Zone

The lower and mid-elevation conifer vegetation types fall within M261Eg (Upper Foothills Metamorphic Belt) to the north of the Forest, from roughly Jerseydale and the Chowchilla Mountains northward. The mixed conifer forest in this region of the forest is comprised of the typical species making up Sierran mixed conifer forest: ponderosa pine (Pinus ponderosa), sugar pine (P. lambertiana), incense cedar (Calocedrus decurrens), and white fir (Abies concolor), but there is a higher proportion of Douglas fir (Pseudotsuga menziesii) than is found to the south. Another unique tree of this part of the Forest is knobcone pine (Pinus attenuata); a fire-adapted, closed-cone pine that may form solid stands on the ridge tops leading to the Merced River.

Coniferous forest, varying from almost pure ponderosa pine forest at lower elevations to classic Sierran mixed conifer higher up, to red fir (Abies magnifica) forest with jeffrey pine (Pinus jeffreyi) in the rockier sites even higher fall within Subsection 261Ep (Lower Batholith) throughout much of the rest of the Forest. The Forest Service sensitive plant Rawson’s flaming trumpet (Collomia rawsoniana), which is found only in the SNF, is restricted to stream sides and meadow edges in Madera County within the Lower Batholith.

In wetter sites such as around meadows or where the water table remains high in the summer, pure stands of lodgepole pine (Pinus contorta ssp. murrayana) prevail (e.g. in the vicinity of Clover Meadow in Madera County).

Montane chaparral may cover extensive acreage in this zone, sometimes naturally on thin, rocky soils or in response to natural disturbances such as fire or avalanches; or in many cases shrub-dominated areas prevail in areas that have been logged or otherwise disturbed by Forest management activities.
Granitic outcrops are abundant in this zone as well, with many Forest endemics and other rare plants such as the Shuteye Peak fawn lily (Erythronium pluriflorum), Kellogg’s lewisia (Lewisia kelloggii ssp. kelloggii), and the orange lupine (Lupinus citrinus var. citrinus) growing exclusively on rock outcrops.

Figure 1.4—Montane mixed conifer forest near Nelder Grove; this stand is in a population of the Forest Service Sensitive lady’s slipper orchid (Cypripedium californicum)
Ch1_Sierra_Fig01.4s.png
Figure 1.4—Montane mixed conifer forest near Nelder Grove; this stand is in a population of the Forest Service Sensitive lady’s slipper orchid (Cypripedium californicum)


Subalpine and Alpine Zones
The subalpine zone falls within Ecological Subsection M261Eq, Upper Batholith. Coniferous forest types within this zone are upper coniferous forest dominated by red fir and lodge pole pine, with an increasing component of western white pine (Pinus monticola) and some stands of mountain hemlock (Tsuga mertensiana). Whitebark pine is found in harsh, windswept areas of the alpine zone, and singleleaf pinyon (Pinus monophylla) is present in sparse amounts in the high elevations of the SNF, though it is primarily an east slope species.

The subalpine meadows of the SNF are also rich in peatlands (fens) and many are inhabited by Sphagnum moss, which was formerly thought to be rare in the High Sierra. Meadows of the subalpine zone in areas with non-granitic geology are prime habitat for rare moonworts, Botrychium spp., and more of these unusual ferns are being found in the central Sierra each year. The alpine zone is generally referred to as “above timberline” but may have stunted or krummholz or stunted trees, especially of whitebark pine.

Figure 1.5—Illustration of different habitats with subalpine habitat around portal lake in the foreground, alpine habitat on the ridge in the background. Photo by J. Clines.
Ch1_Sierra_Fig01.5.png

Figure 1.6—Subalpine meadow near Alstot Lake, Madera County. John Muir Wilderness. Photo J. Clines.Ch1_Sierra_Fig01.6.png

Riparian ecosystems

Riparian vegetation is found along streams and in meadows, springs, and seeps. Riparian vegetation along streams varies considerably within the Forest, ranging from clearly defined bands of riparian forest dominated by white alder (Alnus rhombifolia), willow (Salix spp)., and Oregon ash (Fraxinus latifolia) to simply a strip of herbaceous riparian plants with upland forest trees growing next to the stream throughout much of the conifer forest belt. Meadows are defined as openings in forests which generally have high water tables and are dominated by herbaceous vegetation that is adapted to wet conditions. Meadows are typically heterogeneous, containing patches of different plant assemblages in response to variations in moisture, drainage, elevation, etc. Overall, meadows can be classified as dry, moist, or wet; and montane, subalpine, or alpine (Ratliff, 1985). Some meadows contain areas of peat soils called fens. Fens are areas of perennial saturation where peat soils form because accumulation of organic matter exceeds decomposition (Cooper and Wolf, 2006). Fens are of significance because of their contribution to hydrologic function in meadows and because they provide habitat for several rare plant species.

Fens

Fens, also called peatlands, are perennially saturated areas, usually within meadows, dominated by mosses and herbaceous wetland vegetation. Fens are important because of their function in meadow water storage, and their role in maintaining water quality and hydrologic integrity in meadows. In addition, several sensitive plant species are found primarily in fen habitats. Fens are defined by having at least 40 cm of organic soil within the top 80 cm that has formed in place and where peat-forming vegetation (generally certain species of sedges and mosses) occurs and is entirely rooted within the peat body (Cooper and Wolf, 2006). In the Sierra Nevada, the type of peatland is termed a fen rather than a bog, because the primary source of water is groundwater, although precipitation contributes water as well (Cooper and Wolf, 2006). Inventories of Sierra Nevada fens began in 2003, and are ongoing. The extent to which livestock grazing and trampling affect fens has been investigated in a preliminary study by Cooper et al. (2006), and will continue to be studied in an attempt to determine the amount of such use fen ecosystems can sustain.

The Sierra National Forest provides a diverse range of aquatic and riparian habitat types, ranging from low elevation ponds in chaparral woodland to glacial tarns near granitic alpine ridgelines. The large elevation range from 900 to nearly 14,000 feet results in a huge diversity of habitats and microclimates for a wide variety of aquatic/riparian species. The SNF also provides a variety of riparian habitats associated with streams (both perennial and seasonal), meadows, springs and lakes. Riparian areas are high in biodiversity due to the water, relative humidity, cooler temperatures and complex cover provided. They also serve as important corridors for species dispersal. There are an estimated 15,750 acres of meadow on the Forest and 465,000 acres of Riparian Conservation Areas (RCA) (USDA-FS 2001 and 2004), associated with streams, meadows, springs and lakes.

Riparian areas in the drier southern Sierra Nevada Mountains provide important habitat diversity and habitat for plants/animals. Riparian areas/habitats encompass everything from rivers and creeks, to meadows and springs. The Sierra National Forest has some very large rivers (such as the San Joaquin and Kings) and numerous small and mid-size creeks as well. Meadows range from extremely large to tiny meadows around springs. Large diverse meadow complexes are found in the wetter areas of the Forest and also the drier portions, because of persistent snowpack and extensive shallow groundwater systems.

The riparian areas of the Sierra National Forest can be divided into four broad categories dominated by: forest/woodland; scrub-shrub vegetation; forb (herbaceous) vegetation or meadow; and graminoid (grasses and grass-like) vegetation or meadow. Riparian forest woodlands can be dominated by a variety of coniferous trees, such as pines, firs and incense cedar), and to a less extent deciduous trees, such as black oaks, white alder, Oregon ash, and cottonwood. Having tall shading cover and a large source of organic matter dead-fall (leaves/needles) provides excellent habitat for a diversity of plants and animals. Scrub-Scrub riparian areas are usually dominated by a diversity of shrub habitats. These types of riparian areas provide a rich dense humid habitat for plants, amphibians, and small birds. Forb/herbaceous riparian areas can be found along small creeks and within dry or wet meadows. These areas are usually dominated with wild onion, lupine, bistort, senecio, or corn lilies. Graminoid dominated riparian areas can also be found along small creeks and within wet meadows. These habitats usually have close to 100 percent cover of sedges, grasses, and rushes (graminoid).

Wildlife


Species Overview

The Sierra National Forest is inhabited by approximately 302 species of terrestrial wildlife: 198 bird species, 82 mammal species and 22 reptile species. Four of those species are classified as federal threatened, endangered, proposed or candidate species under the Endangered Species Act (ESA) (Table 1.2). One of those species, the Valley elderberry longhorn bettle is currently in the process of being delisted by the U.S. Fish and Wildlife Service. An additional 11 species are classified as Forest Service sensitive species known to occur, or have the potential to occur, within Sierra National Forest (Table 1.2). Federally designated critical habitat for terrestrial wildlife species is not present on Sierra National Forest. Additional information pertaining to the federally listed, proposed and candidate species, as well as Species of Conservation Concern (SCC), is provided in the Chapter 5: At-Risk Species of the Bioregional Assessment.

Table 1.2—Federally listed threatened, endangered, proposed and candidate wildlife species and Forest Service Sensitive species that are known to occur, or have the potential to occur within the Sierra National Forest
Common Name
Scientific Name
Status
Sierra Nevada bighorn sheep
Ovis canadensis californiana
Endangered
California condor
Gymnogyps californianus
Endangered
Valley elderberry longhorn beetle
Desmocerus californicus dimporphus
Threatened
Pacific fisher
Martes pennanti pacifica
Candidate, FS Sensitive
Bald eagle
Haliaeetus leucocephalus
FS Sensitive
California spotted owl
Strix occidentalis occidentalis
FS Sensitive
American marten
Martes americana
FS Sensitive
Wolverine
Gulo gulo luteus
FS Sensitive
Sierra Nevada red fox
Vulpes vulpes necator
FS Sensitive
Northern goshawk
Accipter gentiles
FS Sensitive
Great gray owl
Strix nebulosa
FS Sensitive
Willow flycatcher
Empidonax traillii
FS Sensitive
Western red bat
Lasiurus blossevillii
FS Sensitive
Pallid bat
Antrozous pallidus
FS Sensitive
Townsend’s big-eared bat
Corynorhinus townsendii
FS Sensitive

The forests of the montane zone are inhabited by some of the most vulnerable at-risk species of Sierra National Forest, principally the California condor and Pacific fisher. California condors, federally listed as endangered, have only recently been reported flying over the furthest southern portion of the Forest, and none have been reported nesting or perching there. Pacific fisher, a candidate for federal listing, as well as the California spotted owl, which is a Forest Service Sensitive Species and a Species of Conservation Concern, are montane forest species with some of the greatest levels of management concern due to their use of large live and dead tree structures for denning, resting, nesting and perching, as well as their need for areas of high forest canopy cover within portions of their home ranges.

The alpine and subalpine zone of the Sierra National Forest is inhabited by one federally listed species, the Sierra Nevada bighorn sheep. This species, however is rarely sighted in the Forest and primarily limited to the highest elevations at the Sierra Nevada crest, in the John Muir Wilderness Area. The core population of this species is found on the east-side of the Sierra Nevada, within Inyo National Forest and the Sequoia Kings Canyon National Park. Two other species, the wolverine and the Sierra Nevada red fox also historically were found in Sierra National Forest and both are Forest Sensitive Species and Species of Conservation Concern. Both of these species were recently petitioned for federal listing, and they are currently under further review by the U.S. Fish and Wildlife Service. Additional details of these and other at-risk species are provided in Chapter 5 of the Bioregional Assessment.

Habitat Overview

Environment and Past Management

The 1.3 million acres of Sierra National Forest contain a high level of wildlife habitat diversity due to the high diversity of elevations, topography and moisture conditions. Specifically, the Forest has an elevation span of over 12,000 feet extending from the highest elevations of alpine habitats at nearly 14,000 ft. elevation to the lowest elevations with oak woodland and chaparral habitats at about 2,000 ft. elevation. Precipitation primarily occurs during the winter season, and it predominately occurs as rain in low elevations and snow at high elevations.

In addition to the diverse environmental conditions present in the Forest, past management has helped cumulatively create the current conditions of wildlife habitats that we have today. One of the most significant past management influences has been fire suppression beginning during the early 1900s. As a result, live and dead fuels have increased to abnormally high levels of abundance, greater than the natural range of variability. These abnormal conditions are represented by Figure 1.7, which shows the difference between the current average Fire Return Interval (FRI) as compared with the reference condition, which is primarily based on the historic conditions. The higher percentages shown in Figure 1.7 represents the higher divergence from those average reference conditions. It is important to keep in mind, however, that missed fire returns does not equate with higher-severity fire -- forest areas that have missed the largest number of fire return intervals in California are burning predominantly at low/moderate-severity levels, and are not experiencing higher fire severity than areas that have missed fewer fire return intervals (Odion and Hanson, 2006, 2008, van Wagtendonk et al. 2012).

Other management, besides fire suppression, also has affected the current conditions of wildlife habitats. Clear cutting through the 1990s created plantations of trees that are often uniform and lack structural attributes such as large down wood and snags. Further, logging prior to 1992 removed significant numbers of large conifers and often focused on the removal of pines. This homogenized stands and removed important seed sources for pine regeneration. Designated areas, such as wilderness, represent different styles of management. Wilderness Areas make up approximately 42 percent (528,000 acres) of the Forest (Figure 1.8), and these areas typically have not been influenced by active management other than by various degrees of fire suppression. In contrast, areas outside Wilderness Areas, which are generally below the 9,000-10,000 foot elevation, have experienced a wide variety of management as a result of historical logging, livestock grazing and residential development.

Prior to the mid-1900s, and to a less extent from the mid-1900s to the early-1990s, logging in Sierra National Forest, primarily within the lower and mid-slope areas (3,000 to 7,000 ft.), typically consisted of removing many of the largest overstory trees. This was particularly significant in what is now the Bass Lake Ranger District, as a result of extensive railroad logging between the late 1880s through the 1930s.

Residential and other structures are present in limited areas that are in and around the Forest, but primarily within mid-elevation areas between about 3,000 and 7,000 ft. elevation. These developments occur on leased Forest Service land, such as in the Huntington Lake community, as well as on nearby private lands, such as the Sugar Pine and Shaver Lake communities. The locations of these structures have influenced current ecological conditions to some degree as a result of past management designed to reduce and prevent forest fires.

These past cumulative factors, combined with nearly a century of fire suppression, have contributed to reducing overall landscape-level ecosystem heterogeneity and to some extent wildlife habitat diversity. This is particularly evident with abnormally high levels of fuel loads, such as extensive areas dominated by shade-tolerant conifers, especially white fir and incense cedar. The past fire suppression, as well as limitations for mechanical and fire restoration work during recent decades, has reduced meadow, shrub, and black oak habitat, due to high tree density and tree encroachment. Overall, this loss of vegetation heterogeneity can detrimentally affect wildlife habitat diversity, as well as reducing ecosystem resilience to stressors, such as climate change and abnormally high levels of tree disease and pest infestations.

Figure 1.7—Departure of the average Fire Return Interval (FRI) as compared with an average historical condition for Sierra National Forest, in percent
Ch1_Sierra_Fig01.8.png
Figure 1.7—Departure of the average Fire Return Interval (FRI) as compared with an average historical condition for Sierra National Forest, in percent.

Figure 1.8. Wilderness Areas in Sierra National Forest.
WildernessMap3.jpg
Figure 1.8. Wilderness areas in Sierra National Forest.


Habitat Characteristics

Broad-scale Characteristics
Wildlife habitats are identified by using a variety of methods, and an important classification system for California is the California Wildlife Habitat Relationships (CWHR) system - Ver. 8.2 (CDFG 2008). This comprehensive system is used throughout California’s National Forests, and it is the system we use here to provide an overview, or broad-scale filter, of habitats within the Sierra National Forest.

The Sierra National Forest contains 30 terrestrial vegetation types, as well as two aquatic habitat types (riverine and lacustrine), as defined by CWHR (Figure 1.9, Table 1.3). Canopy cover density and size classes of those cover types also are shown in Figures 1.10 and 1.11, respectively. A large percentage of those vegetation types are montane forests, such as mixed-conifer, ponderosa pine, hardwood-conifer, white fir, and at the higher elevations, red fir and lodgepole pine. Subalpine and alpine habitats also cover large areas of the Forest in the Wilderness Areas, such as subalpine conifer, lodgepole pine, tundra (grassland) and rock. Meadow and riparian habitats cover relatively fewer acres, however they also tend to have greater species numbers and diversity per unit area, as compared with most other types of habitats.

Table 1.3—Current Sierra National Forest vegetation types as defined by the California Wildlife Habitat Relationships (CWHR).

Habitat Type (CWHR)
Acres
Alpine Dwarf-Shrub
42,503
Annual Grassland
19,473
Aspen
569
Barren
141,884
Blue Oak Woodland
29,893
Blue Oak-Foothill Pine
6,018
Chamise-Redshank Chaparral
4,906
Closed-Cone Pine-Cypress
379
Cropland
146
Deciduous Orchard
4
Jeffrey Pine
28,585
Juniper
155
Lacustrine
22,489
Lodgepole Pine
32,168
Low Sage
423
Mixed Chaparral
50,657
Montane Chaparral
83,724
Montane Hardwood
148,049
Montane Hardwood-Conifer
77,455
Montane Riparian
3,823
Perennial Grassland
392
Ponderosa Pine
73,574
Red fir
141,303
Riverine
810
Sagebrush
619
Sierran Mixed Conifer
269,921
Subalpine Conifer
179,348
Urban
26
Valley Foothill Riparian
251
Valley Oak Woodland
32,067
Wet Meadow
19,355
White fir
2,556

Figure 1.9—Sierra National Forest vegetation types defined by the California Wildlife Habitat Relationship (CWHR) system
Ch1_Sierra_Fig01.9.png

Figure 1.10—Canopy cover density in Sierra National Forest, based on the California Wildlife Habitat Relationship (CWHR) habitat types.
Ch1_Sierra_Fig01.10.png

Figure 1.11—Vegetation size in Sierra National Forest, based on the California Wildlife Habitat Relationships (CWHR) habitat types.
Ch1_Sierra_Fig01.11.png

Habitats are further classified by combining the three CWHR criteria: vegetation type, size and canopy cover to create primary habitat types, such as those shown in Table 1.4 and Figure 1.12. According to the most recent mapping, the largest habitat coverage in Sierra National Forest are the: mid seral coniferous forests (19.9 percent); hardwood and mixed hardwood /conifer forests (15.1 percent); late seral, closed canopy coniferous forests (11.5 percent); and shrublands (9.7 percent).

Table 1.4. Habitat types of Sierra National Forest using 2010 mapping based on 2007 satellite imagery.





2010 Acreage b
Habitat Type
CWHR Habitat Classes a




Acres
%
Lacustrine (Lakes) and Riverine (Streams, Rivers)
Lacustrine (LAC) and riverine (RIV)
23,115
1.7%
West-slope Shrublands (Chaparral types)
Montane chaparral (MCP), mixed chaparral (MCH), chamise-redshank chaparral (CRC)
134,932
9.7%
Sagebrush
Sagebrush (SGB)
620
0.0%
Oak-associated Hardwoods and Hardwood/Conifers
Montane hardwood (MHW), montane hardwood-conifer (MHC)
209,852
15.1%
Wet Meadow
Wet meadow (WTM), freshwater emergent wetland (FEW)
19,356
1.4%
Coniferous Forest,
Early Seral
Ponderosa pine (PPN), Sierran mixed conifer (SMC), white fir (WFR), red fir (RFR), tree sizes 0-11 inches dbh, all canopy closures
47,153
3.4%
Coniferous Forest,
Mid Seral
Ponderosa pine (PPN), Sierran mixed conifer (SMC), white fir (WFR), red fir (RFR), tree size 11 – 24 inches dbh, all canopy closures
275,854
19.9%
Coniferous Forest,
Late Seral, Open Canopy
Ponderosa pine (PPN), Sierran mixed conifer (SMC), white fir (WFR), red fir (RFR), tree size >24 inches dbh, canopy closure 10-39 percent
2,709
0.2%
Coniferous Forest, Late Seral, Closed Canopy
Ponderosa pine (PPN), Sierran mixed conifer (SMC), white fir (WFR), red fir (RFR), tree size > 24 inches dbh, canopy closure > 40 percent
159,865
11.5%
Other land cover
Rock, snow, urban and other vegetation not included in the above cover types, such as grassland and tundra.
514,813
37%
Total

1,388,269
100.0%
a Dbh – Diameter at breast height.
b The 2010 vegetation mapping was created using 2007 LANDSAT satellite imagery to map Ecological Groupings based on CALVEG at a scale of 1:24,000.


Figure 1.12. CWHR habitats in Sierra National Forest.
CWHR_Mar 25.JPG

Aquatic Ecosystems


Species

Fish

The Sierra National Forest is within the Sacramento-San Joaquin zoogeographic province as described by Moyle (2002). Nine of the fish species currently occurring in the Forest are native, with most Forest waters barren of fish prior to man's transplanting activities starting in the late 19th Century. Moyle (1996, 2002) identifies much of the west slope of the Sierra Nevada range above 5,000 feet as being historically fishless due to glaciation during the Pleistocene and steep topography. However, it is noted that trout may have occurred up to 7,200 feet in the Middle Fork of the Kings River (Moyle et al 1996). The fish communities represented on the SNF include the “rainbow trout” and “pikeminnow-hardhead-sucker” assemblages for the zoogeographic province described by Moyle (2002). Elevations on the Forest above approximately 2,500 feet are within the rainbow trout (O. mykiss) assemblage. Habitats are characterized as having more riffle than pools, with water temperatures seldom exceeding 70 degrees Fahrenheit (21° Celsius). Elevations less than 2,500 feet are generally part of the pikeminnow-hardhead-sucker assemblage described by Moyle (2002) as occurring within Sierra Nevada foothill streams. Water temperatures within this transitional area may exceed 70° Fahrenheit (21° Celsius) during the summer, especially during “dry and critically dry” water years. Trout species may persist within these areas, but water temperatures limit the populations and introduced centrarchids (sunfish family) are better adapted to these habitat conditions.

The Sierra National Forest was occupied by eleven native fish species prior to 1850: Kern brook lamprey (Lamptera hubbs); Chinook salmon (Oncorhynchus tshawytscha); rainbow trout (resident rainbow and steelhead)(O. mykiss); Sacramento hitch (Lavinia exilicauda exilicauda); San Joaquin roach (L. symmetricus Ssp.); hardhead (Mylopharodon conocephalus); Sacramento pikeminnow (Ptychocheilus grandis); Sacramento sucker (Catostomus occidentalis occidentalis); prickly sculpin (Cottus asper); and riffle sculpin (C. gulosus).

Three fish species have been identified by the Forest Service as At-Risk species. At-risk species are those currently listed as threatened or endangered, or proposed for listing or candidates for listing under the Endangered Species Act (ESA). These are: Lahontan (O. clarkii henshawii) and Paiute (O. c. seleniris) cutthroat trout. Neither fish is native to the Sierra National Forest, but the species are listed as endangered under the Endangered Species Act and covered under Recovery Plans.

Occupied habitat for the two cutthroat species are within Critical Aquatic Refuges (CARs) (USDA – Forest Service 2001; 2004). CARs are subwatersheds with known locations of threatened, endangered, or sensitive species; highly vulnerable populations of native plant or animal species; or localized populations of rare native aquatic- or riparian-dependent plant or animal species. The primary role of CARs is to preserve, enhance, restore or connect habitats for these species at the local level and to ensure the viability of aquatic or riparian dependent species.

Historically the Forest provided spawning and rearing habitat for anadromous Chinook salmon and steelhead trout. Native fish distribution was limited following the glaciation that occurred during the Pleistocene and the steep topography of the streams tributary to the major rivers. It is estimated that native fish occurred within approximately 100 miles of streams within the Forest (Map 1) (Yoshiyama and Moyle 1996, USDI – NMFS 2010). Of the 11 species native to the Forest, five are considered stable or expanding; one noted as stable; one noted as declining; two noted as species of special concern; and two are extirpated from the Forest (Moyle et. al 1996). Hardhead minnow is listed as a sensitive species by the Forest Service, and Kern Brook lamprey may be designated as sensitive in the near future. Dams downstream of the Forest have extirpated Chinook salmon and steelhead from the Forest.

Salmon accumulate most of their body mass during their years at sea. Their return to freshwater systems represents a source of marine derived protein to predators, and nutrients to aquatic and riparian systems. Marine derived nutrients such as nitrogen and phosphorus are found at higher levels in streams and riparian zones associated with salmon, compared to those streams where salmon did not occur (Naiman et. al 2002; Schindler et. al 2003; Bilby et. al 2003). The loss of Chinook salmon eliminated marine derived nutrients for those portions of the Forest where spawning runs historically occurred.

Forest waters less than 2500 feet in elevation are considered “transitional” or “warmwater” fisheries and are more likely to be occupied by fish from the bass/sunfish and catfish families, although stocked Chinook salmon may be caught on Pine Flat Reservoir, along with occasional brown or rainbow trout at other sites below 2500 feet. Angler experience and success may be affected by the time of year since stream and lake levels may be influenced by spring runoff of snowmelt; low summer/fall flows; drought; or drawdown of hydroelectric/flood control reservoirs in the fall.

Reservoir fisheries exist where dams established as part of hydroelectric power development or flood control has created lakes. Kokanee salmon (O. nerka) are popular at several large reservoirs above this elevation. However, both Bass and Shaver Lakes develop temperature thermoclines over the course of the summer, which provides temperatures suitable for species from the bass/sunfish (centrarchid) and catfish families.

There were approximately 100 miles of streams on the Forest occupied by fish through the 1850s. There are now currently more than 1500 miles of stream occupied by fish species, 11 large reservoirs (greater 150 acres), and 21,550 acres of lakes distributed across the Sierra National Forest, with 31 species of fish now present.

Streams and lakes above approximately 2500 feet elevation are generally considered “coldwater” (water temperatures less than 70°F) fisheries, where anglers may catch rainbow (Oncorhynchus mykiss), golden (O. aquabonita), brown (Salmo trutta), or eastern brook trout (Salvelinus fontinalis). The distribution of fish across the Forest has been greatly expanded (Map 1), and most of the waters on the Forest are currently occupied by non-native fishes as described by Moyle and others (1996).

Amphibians

Jennings (1996) noted that 12 of the 14 frogs and toads native to the Sierra Nevada were in need of some type of protection. Three native amphibians with habitat within or adjacent to the Forest have been identified as At-Risk Species by the Forest Service: California red-legged frog (Rana aurora draytonii), mountain yellow-legged frog (R. sierrae), and Yosemite toad (Anaxyrus (=Bufo) canorus).

California red-legged, which occupied habitats adjacent to the Forest, is listed under the ESA (1996) and possibly extirpated from the Forest. Two native amphibians on the Forest (Yosemite toad and mountain-yellow-legged frog) are currently candidates for listing under the Endangered Species Act, while three others are designated as sensitive by the Forest Service (foothill yellow-legged frog (R. boylii), limestone salamander (Hydromantes brunus), and relictual slender salamander (Batrachoseps relictus (regius)). Jennings (1996) notes the declines of some amphibian species within the introduction of a suite of exotic species (especially fishes) partially as the result of increased distribution of fish across the Forest.

Introduction of non-native fish has provided a predator in aquatic system that has disrupted the connectivity of habitat for amphibian species in particular. Mountain yellow-legged frog (see amphibian declines) populations have become increasingly isolated in part by introduced salmonids. While aquatic habitat remains connected at higher elevations across the Forest, the presence of predatory fish within that habitat limits the ability of mountain yellow-legged frog to disperse.

Non-native bullfrog (R. catesbeiana) has become widely dispersed across the Forest at elevations less than 5500 feet. Bullfrogs are larger than native frogs and may be both a competitor for habitat and a predator. Much of the potential habitat for California red-legged frog and foothill yellow-legged frog is not occupied by bullfrog, however its range is expanding into the lower elevational distribution of mountain yellow-legged frog.

Aquatic invertebrates

Erman (1996) notes that “Aquatic invertebrates are a major source of food for birds, mammals, amphibians, reptiles, fish, and other invertebrates in both aquatic and terrestrial habitats. Changes in a food source of such importance as aquatic invertebrates can have repercussions in many parts of the food web. The life cycles of aquatic invertebrates are intricately connected to land as well as water, and the majority of aquatic invertebrates spend part of their life cycle in terrestrial habitats. Aquatic invertebrates are affected by human caused activities on land as well as activities in the water”.

Knapp (1996) indicates that introduction of non-native fish has effected both zooplankton and benthic macroinvertebrate communities. The zooplankton communities in lakes have shifted from large bodied species to those species with smaller bodies (Bradford et. al 1994). A similar pattern exists for benthic macroinvertebrates in lakes, with many species with free-swimming larvae being absent or reduced in lakes occupied with introduced fish (Bradford 1994). There is limited information on benthic aquatic community on the Forest. Review of 40 benthic macroinvertebrate datasets during the Forest Watershed Condition Assessment indicated 29 samples represented Functioning Properly; 9 indicated Functioning at Risk; and two indicated Impaired aquatic systems.

As previously identified, there are approximately 155 miles of stream on the Forest subject to minimum instream flows downstream of hydroelectric dams. In review of data collected as part of the relicensing of hydroelectric projects (including data from the Forest), Rehn (2009) indicated that benthic macroinvertebrates were most affected by altered hydrologic regime. While the relationships between flow parameters and biotic integrity scores were based on limited data points, it was indicated that lower scores were associated with artificially reduced flows below dams.

Knapp (1996) suggests multiple trophic level consequences of fish introductions, several community-wide effects of trout introductions for aquatic ecosystems in the Sierra Nevada. The effects from introduced trout on native aquatic biota extend beyond interaction at two trophic levels (e.g., trout preying on amphibians, trout preying on zooplankton). Changes in one trophic level due to trout introductions may result in cascading effects to the food web. This was suggested by Jennings and others (1992) through declines in garter snake (Thamnophis elegans), that utilize frog tadpoles as prey. Knapp (1996) also notes that “because introduced trout are likely to be one of the causal factors leading to the decline of at least one Sierran amphibian (Bradford 1989; Bradford et al. 1993), trout may also indirectly cause the decline of T. elegans.” Further, the loss of tadpoles would impact trophic levels, since tadpoles feed on algae resulting in a reduction in algal biomass and altering lake nutrient cycling.

Habitat


The Sierra National Forest provides a diverse range of habitats for amphibians, fish and other aquatic biota. Aquatic habitat types range from low elevation streams in chaparral and oak woodland to glacial tarns near granitic alpine ridgelines. Elevations on the Forest range from about 1,000 to nearly 14,000 feet in elevation, and this topography creates distinct seasonal variation in precipitation.

Approximately 1,300,000 acres drain to the San Joaquin River system via the Merced, Chowchilla, Fresno and Kings Rivers, along with the mainstem San Joaquin River. Aquatic habitat includes an estimated 2,000 miles of perennial streams and rivers, along with 21,550 acres of lakes and ponds. The Sierra National Forest aquatic systems provide habitat for 31 species of fish, with approximately 1,580 miles of stream occupied by fish (USDA-FS 1992). Perennial waters also provide potential habitat for a variety of amphibian and reptile species, as well as benthic macroinvertebrates. Additionally, there are 8,200 miles of intermittent or seasonal streams, some of which also provide habitat for fish, benthic macroinvertebrates and amphibians.

There are more than 1500 miles of stream occupied by fish species, 11 large reservoirs (greater 150 acres), and 7500 acres of lakes distributed across the Sierra National Forest providing a variety of angling opportunities for some 30 species of fish. The Forest provides reservoir fisheries; high mountain lake fisheries; as well as both warm and coldwater fisheries. Streams and lakes above approximately 2500 feet elevation are generally considered “coldwater” (water temperatures less than 70°F) fisheries, where anglers may catch rainbow (Oncorhynchus mykiss), golden (O. aquabonita), brown (Salmo trutta), or eastern brook trout (Salvelinus fontinalis). Reservoir fisheries exist where dams established as part of hydroelectric power development or flood control has created lakes. Kokanee salmon (O. nerka) are popular at several large reservoirs above this elevation. However, both Bass and Shaver Lakes develop temperature thermoclines over the course of the summer, which provides temperatures suitable for species from the bass/sunfish (centrarchid) families. Forest waters less than 2500 feet in elevation are considered “transitional” or “warmwater” fisheries and are more likely to be occupied by fish from the bass/sunfish and catfish families, although stocked Chinook salmon may be caught on Pine Flat Reservoir, along with occasional brown or rainbow trout at other sites below 2500 feet. Angler experience and success may be affected by the time of year since stream and lake levels may be influenced by spring runoff of snowmelt; low summer/fall flows; drought; or drawdown of hydroelectric reservoirs in the fall.

Aquatic species viability may be limited by the ability of species to access partners for breeding. Sierran systems were naturally limited by post-glaciation, which resulted in limited occupancy by fishes. However, aquatic/riparian species capable of moving through the terrestrial environment (such as herpetofauna or insects with terrestrial life stages) were able to utilize habitat across the Forest.

Most of the waters on the Forest are currently occupied by non-native fishes as described by Moyle and others (1996), thus the distribution of fish across the Forest has been greatly expanded. Additionally, two stream segments located within or adjacent to the Forest are listed as impaired by the State Water Resources Control Board (SWRCB 2008). Finally, sediment accumulation in pools and riffles has reduced the quality of aquatic habitat on some stream segments within the Forest.

Dams/Diversions and Habitat Connectivity

As described under the Sierra Nevada Ecosystem Project (SNEP 1996), connectivity of aquatic habitat on the Sierra National Forest has been altered by dams, diversions, and road crossings. Some native fish species have declined or been extirpated from the Forest. Introduction of non-native fish have greatly expanded the distribution of fish across the Forest. Distribution of native frogs and toads has declined. Alteration of fire regime and climate change has also contributed to alteration of Aquatic/Riparian Habitat.

There are 50 dams and diversions on the Forest, which have been built for flood control, generation of hydroelectric power, and water rights. Dam and diversions may contribute to aquatic habitat alteration through flooding, removal of water, alteration of flow regime, blocking fish movement or migration, and contribute to species isolation (Moyle et. al 1996). Water temperatures downstream of dams are affected by volume of flow and temperature of the upstream reservoir. Dams and diversions affect flow over approximately 220 miles of streams on the Forest. Several streams receive enhanced flows as a result of flow diversion however a majority are subject to less flow than if the diversion was not present. There are approximately 155 stream miles on the Forest subject to flow regulation under licenses from the Federal Energy Regulatory Commission (FERC). Streams under FERC licenses have conditions for providing minimum instream flows (MIF).

Culverts on road crossings can also disrupt habitat connectivity by restricting upstream movement by species. Culverts may represent a total barrier to fish upstream movements, or force amphibians and reptiles to attempt road crossings that my subject them to mortality. Fish passage success is dependent on the swimming capability of the fish, lifestage of concern, stream discharge, and the relationship of fish movement with stream discharge. It is estimated there are more than 14,700 crossings on the Sierra National Forest, with more than 1,500 of these crossings on perennial streams. The percentage of the culverts that provide for upstream passage is not known. However, in a limited analysis of perennial crossings on the Forest during 2011, 88 of 121 crossings evaluated would not provide upstream passage for adult rainbow trout.

Sediment/Water Quality

Segments of Forest streams have been surveyed for stream channel characteristics and stability between 1989 and 2008. Channels and riparian areas were evaluated using various methodologies, including Rosgen channel typing and Pfankuch channel stability ratings.

Rosgen Channel Typing

Channel reach types (Rosgen 1996) were determined based on channel attributes such as width/depth ratio; gradient; sinuosity; and substrate, along with sediment and transport characteristics. Approximately 465 miles of perennial stream channel have been evaluated across the Forest. Stream reaches with low sensitivity are bedrock/boulder (Rosgen channel types A1-2, B1-3, C1-2, F1-2 and G1-2) and represent approximately 60 percent of the streams evaluated. These channel types are considered inherently stable and are not significantly influenced by land management activities. However, sediment build-up can occur in these channels if upstream stream channels degrade. Effects to aquatic habitat would be likely on those Rosgen channel types considered as sensitive, degraded or unstable (sensitivity of moderate and high in Table 1.6).

Pfankuch channel stability ratings

The Pfankuch channel stability rating (USDA-FS 1975) developed to evaluate the stream channel condition and stability from within the floodplain and stream channel. This method utilizes observation of attributes from the upper banks, lower banks and channel bottom. Channels are categorized into three ratings of poor, fair or good. Table 1.5 indicates the Modified Pfankuch streambank stability condition. Channel types were evaluated in terms of sensitivity to disturbance as presented by Rosgen (1996), which varies by channel gradient and size of substrate. The Modifications proposed by Rosgen evaluate each channel type separately in terms of vegetative bank cover, stream bank cutting, channel bottom deposition, channel bottom scour and deposition and percent stable material. Under Rosgen’s (1996) modified approach, channels are evaluated considering sensitivity to disturbance, recognizing channel characteristics rather than evaluating all channels against a common metric.

While approximately 90 percent of the naturally unstable channel types had at least Fair channel stability, 54 percent of the moderately sensitive channels were indicated to have Poor channel stability under the Modified Pfankuch approach. Table 1.5 displays the channel stability conditions for sensitive, degraded or naturally unstable within the analysis units.

Table 1.5—Channel sensitivity and stability data
Rosgen Sensitivity (mi)
Modified Pfankuch Ratings Moderate sensitivity reaches (mi)
Modified Pfankuch Ratings High sensitivity reaches (mi)
Low
Moderate
High
Good
Fair
Poor
Good
Fair
Poor
274.5
71.4
117.4
13.0
19.5
38.8
75.6
29.4
12.4

The Sierra Nevada Ecosystem Project (SNEP) (1996) identified both excessive sediment yield and water quality impacts as stressors of aquatic systems. Erosion and sedimentation are probably the most common water quality issues related to forest management. Unfortunately, very few records of annual sediment loads are available for streams on or near NFS lands in the Sierra Nevada. Roads are a documented source of disturbance in managed watersheds (Trombulak and Frissell 2000; Switalski et. al 2004). Roads and cattle grazing represent sediment source mentioned in SNEP (1996).

Sediment

Sediment studies have identified roads producing more sediment than other forest management practices (Robichaud et al 2010). Roads can also affect meadows and wetlands directly by encroachment and indirectly by altering surface and subsurface flow paths. Alteration of the hydrologic flow paths can indirectly affect meadow and wetland function, with the effects extending far beyond the area road itself. The effects can include erosion and/or lowering of the water table.

The potential for water to run down roads or trails is termed ‘diversion potential’. When this occurs, stream flow diversions can be a major cause of road-related erosion (Furniss et al 1997). When roads concentrate surface flow and deliver it to streams via surface flow paths, they are termed ‘hydrologically connected’ and they functionally increase the drainage density (Wemple and others 1996). In a study of forest road segments on the Eldorado NF, Coe (2006) found that 25 percent of the road segments surveyed were hydrologically connected. A local study in the Kings River Experimental Watershed (KREW) area found that 13 percent of the road length in the study area was hydrologically connected (Korte and MacDonald 2005). Robichaud and others (2010) note that studies in the western U.S. have found between 23 and 75 percent hydrologic connectivity of roads. The Forest works at the project scale to identify and reduce instances of roads being connected.

The majority of the Forest includes cattle grazing under permits. Numerous effects on aquatic habitat and species have been attributed to prolonged use of riparian areas by cattle. Literature suggests potential effects from cattle grazing such as altering channel function, which reduces natural processes, habitat diversity and habitat complexity for aquatic or riparian animals (Clary and Webster 1989; EPA 1991; Meehan et. al. 1991; Belsky et. al. 1999). Animal wastes could directly impair water quality through bacterial contamination and increasing nutrient levels (EPA 1991; Derlet et al. 2006; 2008; 2010), although Campbell and Allen-Diaz (1997) and Allen-Diaz and others (2010) reported no significant differences in nitrate, orthophosphate, dissolved oxygen, temperature, or pH in a study evaluating grazing effects to water quality. While these factors could result in negative effects to aquatic/riparian habitat, quantifying effects related to continued cattle grazing and recovery from past effects has proved difficult to evaluate due to absence of reference sites that have never been grazed by livestock (Kattelmann 1996).

Many of the effects described in literature are noted as resulting from “heavy” or “overgrazing”. Cattle grazing permits are administered under U.S. Forest Service, which include compliance with standards and guidelines from the Sierra National Forest Land and Resources Management Plan (USDA – Forest Service 1992; 2001; 2004). Grazing permits are subject to NEPA analysis where identified negative effects can be mitigated. It is expected that cattle grazing continues to result in exposed streambanks and erosion on a local basis.

Water quality

Water quality across the Forest is managed under the Central Valley Basin Plan for the San Joaquin and Sacramento River Basins (Central Valley Regional Water Quality Control Board 2007), and the Tulare Lake Basin (CVRWQCB 2004). These plans designate the beneficial uses to be protected, water quality objectives, and an implementation program for achieving objectives. Beneficial uses identified in the plans include: Municipal and Domestic Supply; Hydropower Generation; Water Contact Recreation; Non-contact Water Recreation; Rare, Threatened, or Endangered Species; Warm Freshwater Habitat; Cold Freshwater Habitat; Migration of Aquatic Organisms; Spawning, Reproduction, and/or Early Development; Freshwater Replenishment; and Wildlife.

Summer water temperature monitoring has been implemented by the Forest, and as part of the relicensing for hydroelectric projects. Data from approximately 200 sites suggests that the transitional zone between cold and warm-water habitat may be influenced by minimum instream flows and that smaller streams above 3000 feet elevation currently meet Moyle’s (2002) description of the rainbow trout zone (<21° Celsius). Water temperatures in larger streams may be influenced by limited riparian shading, especially in streams flowing through bedrock canyons.

Several drainages are listed as having impaired water quality by the Central Valley Regional Water Quality Control Board (CVRWQCB). A water body or segment of a water body (e.g., a fresh stream, river or lake) that does not meet (or is not expected to meet) water quality standards may be considered a “Water Quality Limited Segment” (WQLS). WQLS are added biennially by the CVRWQCB to the Clean Water Act Section 303(d) list of impaired waters.

A segment of Willow Creek was added to the 303(d) list in 2006 for failing to meet the water temperature objective. The listed segment is 6.2 miles long and is located downstream of the confluence of the North and South Forks of Willow Creek. The source of impairment is restricted (regulated) flow and excess fine sediment causing an increase in stream temperature. The Total Maximum Daily Loads (TMDLs) is scheduled to be completed by 2019.

The Fresno River (downstream of the SNF) was added to the 2008 303(d) list for failing to meet the dissolved oxygen (DO) objective. The listed segment is 30 miles long and is located between the confluence of Lewis Fork and Nelder Creeks and the Hensley Reservoir. The source of the impairment is unknown. Dissolved oxygen levels in the Fresno River could be influenced by the water quality (particularly sediment, turbidity, nutrients and temperature) of contributing waters from Miami, Lewis Fork, and Nelder Creeks. The TMDL is scheduled to be completed by 2021.

Watershed Condition Assessment

The Forest completed a Watershed Condition Assessment (WCA)(USDA –Forest Service 2010). The WCA represents a systematic, flexible means of classifying watersheds based on a core set of national watershed condition indicators. It included professional judgment exercised by Forest interdisciplinary teams, GIS data and national databases to the extent they were available and written rule sets and criteria for indicators that describe proper function, functioning-at-risk, and impaired conditions. The WCA evaluated 65 12th field Hydrologic Unit Code (HUC) watersheds that are located within or partially within the Forest. Watersheds were evaluated as being in Good (Properly Functioning); Fair (Functional at Risk); or Poor (Impaired Function) considering both aquatic (physical and biological conditions) and terrestrial (physical and biological) data.

Watershed condition refers to the state of the physical and biological characteristics, along with the processes within a watershed that affect the hydrologic and soil functions supporting aquatic ecosystems. Watershed condition reflects a range of variability from natural pristine (properly functioning) to degraded (severely altered state or impaired). Watersheds in properly functioning condition have terrestrial, riparian, and aquatic ecosystems that capture, store, and release water, sediment, wood, and nutrients within their range of natural variability for these processes. Properly functioning watershed conditions create and sustain functional terrestrial, riparian, aquatic, and wetland habitats that are capable of supporting diverse populations of native aquatic- and riparian-dependent species.

In general, the greater the departure from the natural pristine state, the more impaired the watershed condition is likely to be. Properly functioning watersheds provide for high biotic integrity; are resilient and recover rapidly from natural and human disturbances; exhibit a high degree of connectivity; provide important ecosystem services such as high quality water, recharge of streams and aquifers; and maintain long-term soil productivity. The results of the WCA for the Forest indicate that 25 watersheds would be classified as being in Good (43% of Forest drainage), 33 watersheds would be classified as being in Fair (52% of Forest drainage), and 7 watersheds would be classified as being in Poor Condition (5% of Forest drainage). The Upper Big Creek and Willow Creek watersheds were identified as Forest priorities for restoration treatments. Habitat fragmentation, flow alteration, exotic species, road density, and road proximity to water were the most common stressors affecting watersheds in less than Good condition.

Drivers and Stressors


Disturbances have occurred for millennia, and plant species and communities have evolved and adapted to them over time. Disturbances perform important functions within the Sierran ecosystem, such as insect outbreaks that modify species composition and structure by thinning individual and groups of trees and creating openings. This and other types of disturbance also create spatial diversity across the landscape which can provide opportunities for shrubs, forbs, and other low vegetation to maintain species diversity through time. Because of these types of interactions and disturbances cannot be viewed as necessarily destructive or damaging. They are major processes that develop resources for use by other components of the ecosystem and established system structure. However, major drivers and stressors of ecosystems can also be abnormal outside the desired or reference range of ecosystem variability, thus potentially resulting in severe disruptions to ecosystems. The following is an overview of some key drivers and stressors for terrestrial and aquatic ecosystems including those created by humans. Chapter 3 of the assessment provides additional details of the most wide-spread and influential drivers and stressors, such as fire and climate change.

Fire

Fire is a major influence on type, composition and juxtaposition of ecosystems in the Sierra National Forest. Within the Southern Sierra Province, fire occurred at a variety of intervals. "More important than average fire return intervals, the distribution of fire-return intervals can vary substantially among locations in the landscape" (van Wagtendonk and Fites-Kaufman 2006, p. 279). The following graph illustrates the variety of fire return intervals detected in small sample areas and compares mesic and dry sites.

FRI variation.jpg

Along with variation in fire return intervals, the severity within and between fires was variable and related to regional drought and weather conditions (van Wagtendonk and Fites-Kaufman 2006). Low severity fire is often emphasized in discussion about fire regime pine and mixed conifer forest, however, mixed-severity fire, including high-severity fire, is also a natural condition in ponderosa-pine/Jeffrey pine and mixed-conifer forest. Given the fact that fire is a natural part of the ecosystem, one of the most significant changes during the past century has been fire suppression management. At the same time, the length of fire season is extending as a consequence of climate change, thus exacerbating the situation. As a result, live and dead fuels in some parts of the landscape have increased to levels that are greater than the natural range of variability. These conditions are represented by Figure W-1, which depicts the divergence of the current Fire Return Intervals (FRI), as compared with average reference conditions. The following bullets are key concerns pertaining to fire as well as fire suppression.
  • Fire is a key landscape driver in how it contributes to ecological integrity and sustainability, as well as the amount, juxtaposition and quality of wildlife habitats. One such concern is the long-term declining trend of early seral vegetation (e.g., forage habitat) due to fire suppression and lack of any other disturbance that would result in tree mortality. Specific examples of declining habitat for deer and other species include past and current loss of meadow and shrub habitat as a result of tree encroachment. Studies conducted by Longhurst and others (1976) “…concluded that decreased acreage of controlled burns and wildfires in California has contributed to the decline of deer numbers.” In addition, complex early seral forest is important for a whole host of avian species including black-backed woodpeckers as well as shrub dependent birds.
  • Aquatic/riparian affects from fire occurrence and intensity is related to recurrence. Fire suppression activities have resulted in an altered recurrence cycle. That has resulted in an increase in forest density and the abundance of shade-tolerant species. These changes have affected habitat for some aquatic/ riparian species. The USDI-USFWS (2002) identified that “Fire suppression, and changes in fire frequency and hydrology, has probably contributed to the decline of Yosemite toads through habitat loss caused by conifer encroachment on meadows. Under natural conditions, conifers are excluded from meadows by fire and soils too saturated for their survival. But as conifers begin to encroach on a meadow, if they are not occasionally set back by fire, they transpire water out of the meadow, reducing the saturation of the soils, and facilitating further conifer encroachment.
  • A large, high severity fire could disrupt flow regime and alter stream channel dynamics. Soil water storage; base flow; streamflow regime; peak flow; water quality (sediment, temperature, pH, ash slurry); and chemical characteristics can be affected by wildfire (Neary et al. 2005). In an effort to reduce fire intensity and protect communities, more treatments to reduce stand density would be expected in the future. Both wildfire and fuels treatments may result in changes to habitat and potentially direct effects to aquatic/riparian species.

Climate Change

Climate change is a key landscape stressor affecting long-term ecological conditions. It is expected that air temperatures and precipitation patterns may change across the Forest over time. The Forest includes elevational zones characterized as having warm/hot summers (varies by elevation) and cool winters. Most precipitation above 5500 feet falls in the form of snow from fall through spring. Change is expected to be reflected through an increase in daily maximum, minimums, and mean air temperatures, along with altered rainfall patterns. Meyer and Safford (2010) examined fire trends presented in Miller et al. (2009), and incorporated long-term weather stations within or adjacent to the Sierra National Forest to illustrate that mean annual temperature at Huntington Lake has increased by 1.8º F, with a mean minimum (nighttime) increase of 4º F since 1915. Utilizing information projected by Meyer and Safford (ibid), mean annual temperature increases by 0.3 º F; mean annual minimum temperature increases by 0.4 º F; and mean annual maximum temperature increases by 0.19 º F over the 10-year period at Huntington Lake (7000 feet). The following are some key points pertaining to climate change ecosystem stressors.
  • Climate change may facilitate expansion of non-native invasive species. Invasive species have altered terrestrial and aquatic/riparian systems and biodiversity across the Forest.
  • Climate change has been suggested as a contributing agent in the decline of amphibians. Reaser and Blaustein (in Lannoo 2005) summarize that site specific review of amphibian declines indicate possible global changes, and that regional warming, increasing ultraviolet radiation, and diseases are a potential result of global change. California anticipates warmer temperatures, accompanied by altered patterns of precipitation and runoff related to climate change (DWR 2007). Annual runoff in the San Joaquin River basin has declined by 19% over the past 100 years, and projected precipitation alterations could reduce the snowpack by 25% by the year 2050.
  • Thompson (2005) summarizes that direct solar radiation has the greatest influence on water temperature, thus managing to maintain or improve shade is important to reduce heat flux. Precipitation changes would be expected to reflect a great deal of variability. Information from Meyer and Safford (ibid) project an increase in annual precipitation of 2.1 inches at Huntington Lake over the 10-year period, but the projections at Grant Grove in Kings Canyon National Park project no change. Spring runoff is occurring earlier in the year and fraction of runoff occurring in the spring is decreasing. With less snowfall expected to result from elevated air temperatures associated with climate change, it is likely that less water would be available during the late summer and that the water would be warmer than current conditions. An increasing elevation of snow level would reduce the amount of shallow pools during the spring, which provide breeding habitat for Yosemite toad. A similar effect to shallow lakes would reduce the suitability of habitat for mountain yellow-legged frog, which could result in localized extirpations in a species with a high degree of site fidelity.
  • Lind (2008) notes that amphibian and reptile populations respond to changes and variability in air or water temperature, precipitation, and the hydro-period of their environments. Over the short-term (annually), these factors can influence reproductive success rates and survival to metamorphosis. Over the long term, the frequency and duration of extreme temperature and precipitation events can influence the persistence of populations and structure of meta-populations on the landscape. The net effect of less water and higher temperatures would be a reduction in the quantity and quality of aquatic/riparian habitat. Herpetofauna would likely be concentrated at sites where water is available, increasing their susceptibility to predators at these sites. The changing conditions of habitat would provide conditions more favorable for invasion by species currently occurring at lower elevational sites, and possibly an increase in non-native species. It is probable that the range of bullfrog would continue to expand across the Forest.

Invasive Species

The influx of non-native species of animals and plants since the first Europeans arrived in California has changed the ecosystems of the Sierra Nevada and this continues to be a major and increasingly important stressor in the Sierra National Forest.

Land Use and Management


The following are some land use and management activities that can have some degree of stress on the ecosystems.
  • Recent research (Gabriel et al. 2012) has shown that rodenticide poisons, such as those distributed through illegal marijuana growing operations, can have detrimental impacts on species such as mice, rats and squirrels, which in-turn can also detrimentally influence the wellbeing of hunted and non-hunted wildlife populations, as well as potentially negative affects to humans which consume those species.
  • Vegetation and ecosystem management actions can affect the quality and juxtaposition of habitats used by fish, wildlife and rare plant populations, particularly in how conditions diverge from the natural range of variability.
  • Hunting regulations and hunter harvests affect wildlife populations, as well as prey species used by some of those populations.
  • Existing conditions of aquatic/riparian habitat have been influenced by a variety of drivers and stressors, most relating to human disturbance since 1850. Among the findings within the Sierra Nevada Ecosystem Project (SNEP 1996) was that the aquatic/riparian systems were the most altered and impaired habitats of the Sierra Nevada. This finding was based on effects to stream flow (through dams and diversions altering stream-flow patterns and water temperatures); effects to riparian areas damaged by placer mining and grazing; excessive sediment yield into streams; water-quality impacts; introduced aquatic species; amphibian species declines; loss of anadromous fishes (Chinook salmon and steelhead); aquatic invertebrates local degradation of habitat; and due to food chain relationships, impacts to invertebrates have significant cascading effects on other animals.
  • Snowmobiles – which are permitted to travel off designated routes -- put increased stress on wildlife, including ungulates and subnivean species. Snowmobile emissions also contribute to acid pulse during spring runoff which impacts aquatic species. [See, e.g. Ingersoll, G.P., 1998. Effects of Snowmobile Use on Snowpack Chemistry in Yellowstone National Park. J. Ruzycki and J. Lutch, “Impacts of Two-Stroke Engines on Aquatic Resources” 1999 (available at http://beringiasouth.org/impacts-of-two-stroke-engines-on-aquatic-resources.) Jarvinen, J.A., and W. D. Schmid. Snowmobile Use and Winter Mortality of Small Mammals. Pp. 131-141 in M. Chubb (ed.), Proc. of the Snowmobile and Off-Road Vehicle Research Symposium. Michigan State Univ. Tech. Rep. 8, 1971. Severinghaus, C.W. and Tullar, B.F. 1978. Wintering Deer versus OSVs. New York State Department of Environmental Conservation]
  • Snowmobiles may be significant contributors to aquatic and terrestrial pollution in off-road areas. High-speed snowmobile free-play can damage high alpine slopes and meadows. Acid pulse during spring runoff, created by motorized use such as snowmobiles, can harm aquatic species. [Ingersoll, G.P., 1998. Effects of Snowmobile Use on Snowpack Chemistry in Yellowstone National Park. J. Ruzycki and J. Lutch, “Impacts of Two-Stroke Engines on Aquatic Resources” 1999 (available at http://beringiasouth.org/impacts-of-two-stroke-engines-on-aquatic-resources) E. Gage and D.J. Cooper, “Winter Recreation Impacts to Wetlands: A Technical Review”, Mar 2009 (Submitted to Arapaho-Roosevelt National Forests). Shaver, C., Morse, D., and O’Leary, D., 1998. Air Quality In the National Parks. U.S. Department of the Interior, National Park Service, Air Quality Division. Report prepared by Energy and Resource Consultants, Inc., NPS Contract No. CX-0001-4-0054]

Trends

Terrestrial
Species
Trend information pertaining to the At-risk Species is provided in Chapter 5 of the Bioregional Assessment.

Habitat

Introduction

The Sierra National Forest future habitat trends assessed here assume a 10-20 year period with management similar to current conditions. Habitat trends are inherently driven by ecosystem dynamics, such as natural succession, including plant establishment, growth and decay, as well as ecosystem processes and stressors, such as fire and climate change. Key elements of these factors and processes are described in the Science Synthesis, the Bioregional Assessment, and in this and other chapters of this assessment. Habitat trends also are directly and indirectly influenced by past, present and future management actions.

The current management framework for Sierra National Forest consists of the 1992 Land and Resource Management Plan (LRMP) Record of Decision (ROD) (USDA-FS 1992), as well as amendments. The 2001 Sierra Nevada Forest Plan Amendment (SNFPA) ROD (USDA-FS 2001) included Standards and Guidelines (S&Gs) focusing on fuels treatments, particularly areas within the Wildland Urban Interface/Intermix zones (WUI). In 2004, a Supplemental EIS (USDA-2004a) was written to the SNFPA along with implementing a new ROD (USDA-FS 2004) which replaced the 2001 decision in its entirety.

Beginning in 2004, and with greater refinement over recent years, the Sierra National Forest has emphasized ecosystem management focusing on ecological restoration through initiating or accelerating the recovery of ecosystem health, integrity and sustainability. Ecological restoration is the process of assisting the recovery of resilience and adaptive capacity of ecosystems that have been degraded, damaged, or destroyed. Restoration focuses on establishing the composition, structure, pattern, function and ecological processes necessary to make terrestrial and aquatic ecosystems sustainable, resilient, and healthy under current and future conditions (Forest Service Manual (FSM) 2010). An important aspect of this ecological restoration is restoring forests to a healthy, diverse, fire resilient condition that more closely resembles a range of desired reference conditions. This is partly accomplished by reducing forest stand densities and fuel loads using thinning and underburning, as well as expanding the use of prescribed fire to more often use mixed-severity prescribed fire (as opposed to only using low-severity prescribed fire) and managed wildland fire.

Considerations for Estimating Future Trends

The CWHR habitats previously shown in Table 1.4 provide a broad perspective of key habitats used by a variety of species over a large portion of the Sierra National Forest landscape. These same habitats also are considered for the following trend assessment.

This assessment of future trends also considers past trends that occurred during the same or similar management framework as the projected trends. For this assessment, the best information available to represent these conditions is the vegetation mapping in 2001 and 2010. Habitat changes represented by these two years do not represent a complete template for predicting future trends, yet they do provide an indication of what may occur in the future.

There are two concerns for comparing the habitat mapping in 2001 and 2010: 1) changes in mapping resolution and preciseness, and 2) changes in management. The first concern is clearly evident because the mapping resolution for the 2010 vegetation maps (i.e., 2.5 acres) is approximately twice the resolution of the 2001 mapping. This variation prevents a precise comparison among years however it does provide enough information for general descriptive comparative assessments. These are only draft comparative statements at this time, as further investigations are underway. Of particular note, the comparison between the 2001 and 2010 mapping is not appropriate for fine scale comparisons, yet it has some value when estimating broad-scale trends, such as used here for comparing changes in conifer forests, hardwood forests, as other broad-scale habitat types. Forest Service comparative resolutions and preciseness will continue to improve through time with new imaging and mapping technologies that are supported by funding and expertise.

The second concern for assessing past habitat trends, as well as estimating future trends, is the influence of changed management through time. The current, and projected, management framework was initially implemented in 2004 (USDA-FS 2004), which only partially covers the 2001 to 2010 trend assessment. However, thinning management, primarily focused on smaller tree thinning, occurred throughout the 2001 – 2010 period and even began about five years earlier, in approximately 1995, when management shifted from even-age timber harvesting to individual tree thinning. Thinning management, predominantly smaller tree thinning, became more defined under the 2001 SNFPA and more refined under the 2004 SNFPA. Therefore, the prevalent management throughout the 2001 to 2010 comparative period consisted of individual tree thinning, primarily of smaller trees.

The current management framework, which was adopted in 2004, includes many standards and guidelines, such as retaining live trees greater than 30 inches dbh and snags greater than 15 inches dbh, except for hazard tree considerations. These and other numerous S&Gs can be found in the 2004 SNFPA ROD (2004 SNFPA ROD). In addition to these S&Gs, Sierra National Forest also has been actively implementing design criteria for most projects based on new science and other information. These proactively adapted management criteria include many recommendations from the PSW General Technical Report (GTR) 220: An Ecosystem Management Strategy for the Sierran Mixed-Conifer Forests (North et al. 2009), GTR 237: Managing Sierra Nevada Forests (North et al. 2012), as well as other science and other information, such as conservation measures for the Pacific fisher and other species. Many of these new practices have been adaptively integrated into nearly all forest management projects (e.g., ecosystem restoration projects) by Sierra National Forest since at least 2009. Those practices, along with continued adaptive improvements, are expected to continue in the future, as well as other new management adaptations from new science, technologies and collaboration. Therefore, we cannot know all details of how new adapted management practices will influence future habitat projections, nor can we fully understand the full array of ecosystem changes, particularly as a result of ecosystem stressors such as climate change. However, we do know enough about these past and projected changes to provide broad estimates of change, along with clarifications and caveats.

Past Trends

Broad-scale habitats in the Sierra National Forest have remained relatively stable between 2001 and 2010 (Table 1.6). The management framework during this period also reflects this habitat stability, which has focused on forest sustainability, thinning smaller trees and retaining and growing larger trees. There are, however, some increasing and decreasing trends that are of concern, as noted in Table 1.5. Although the 2001 and 2010 mapping resolution issues do not allow precise details of those trends, considerations of known and projected management and ecosystem drivers and stressors provide further insight into the pace and scale of those trends.

Future Trends

Broad-scale habitats generally are expected to remain relatively stable over the next 20 years (Table 1.6) assuming current management and also considering the relatively slow progression of natural succession. This scenario assumes that the pace and scale of forest treatments, fire suppression, and wildfires would remain similar to the current levels. However, these broad-scale habitat classifications are not intended to assess the finer details of ecosystem health. Nor do they accurately reflect the potential risks of large scale habitat change as a result of ecological stressors, such as climate change and large scale, high intensity fire that is abnormally higher than the natural range of variability. Therefore, some of these key considerations are included in Table 1.5 to provide insight as to their potential effects on future conditions. Supporting details of these ecosystem features, processes, drivers and stressors are provided in a number of the documents associated with this assessment, including the Scientific Synthesis, Bioregional Assessment, and assessments of the natural range of variability, which is currently being drafted.

Table 1.6. Estimated past and future broad-scale habitat trends in Sierra National Forest.
Habitat Type
Current Percent of Sierra National Forest
Estimated Past Trends 2001-2010 a
Estimated Future Trends 2012-2032 b
Lakes and Riverine
1.7
No major change.
No major change expected.
Wet Meadow
1.4
Decreasing trend, potentially due to tree encroachment and climate changes resulting in less water availability.
Decreasing trend expected if: 1) pace and scale of meadow restoration does not increase, such as by reducing tree encroachment, removing roads and trails from meadows that cause a change in hydrology, eliminating grazing impacts that result in drying of meadow systems and cause a change in hydrology; and 2) continued climate changes resulting in less water availability.
Sagebrush
<0.1
No major change.
No major change expected.
Shrublands (Chaparral)
9.7
No major change.
Major change not expected, although large scale, high intensity fire in a warming climate can lead to shifts from forests to shrublands.
Oak-associated Hardwoods and Hardwood/
Conifers
15.1
Declining trend, potentially as the result of succession moving some stands into coniferous forest, possibly due to fire suppression.
Major change not expected however, large scale, high intensity fire in a warming climate can lead to shifts from conifer forests to hardwood dominated forests.
Coniferous Forest,
Early Seral
3.4
Decreasing trend most likely due to fire suppression, salvage logging, and natural succession shifting forests into mid-seral condition.
A continued gradual decreasing trend at the fine scale is projected due to lack of fire. In addition, when openings are created through mechanical thinning or other disturbance, the tree-centric management focus of replanting and limiting or eliminating shrubs and other understory species in the openings limits the development of early seral conditions and speeds up the rate of succession from grass/forbs/shrubs and to conifers. Projected increases in large scale fire that is more severe would favor the development of early seral conditions. However, commonly implemented salvage logging practices would substantially degrade early seral conditions by the simplification of the affected area. Known and projected climate changes may gradually result in lower tree density and patchy tree die-off due drought conditions, thereby creating space for early seral conditions.
Coniferous Forest,
Complex Early Seral
Unknown
Decreasing due to fire suppression, salvage logging, reforestation (by humans), and mechanical thinning.
Continued gradual decreasing trend is estimated due to overall forest management measures. Increased mixed-severity fire could increase this habitat type but only if a) the fires burn areas with the pre-fire conditions necessary to create complex early-seral forest, and b) the areas that burn are not salvage logged and are allowed to regenerate naturally (i.e., no human reforestation).
Also, even aged cutting does not create complex early seral forest.
Coniferous Forest,
Mid Seral
19.9
No substantial change.
Projected gradual decreasing trend as the large amount of mid-seral stands progressively grow into late-seral stands, although somewhat moderated by smaller amounts of early-seral forests progressing into mid-seral forests. Major loses are projected if large scale, high intensity fires occur in these forests due to high fuel loads in many of these forests.
Coniferous Forest, Late Seral, Closed Canopy
11.5
No substantial change.
Projected gradual increasing trend as the large amounts of mid-seral stands progress into late-seral forests. The continued management framework would retain nearly all trees >30 inches dbh, thus increasing the number of stems per acre. Determining if such increases are greater than desired reference conditions requires an analysis of existing conditions, mortality, and growth. Losses to this seral stage also could occur as a result of large scale, high intensity fire, particularly in those areas with fuel loads abnormally higher than the natural range of variability. However, it is important to keep in mind that forest areas that have missed the largest number of fire return intervals in California are burning predominantly at low/moderate-severity levels, and are not experiencing higher fire severity than areas that have missed fewer fire return intervals (Odion and Hanson, 2006, 2008, van Wagtendonk et al. 2012).
Coniferous Forest,
Late Seral, Open Canopy
0.2
Increasing trend, albeit less than 2,000 acres. Trend may be due to small scale wildfire, patchy insect and disease infestations, and smaller-scale timber treatments.
This small amount of habitat is predicted to remain stable although possibly increasing as a result of closed canopy forests shifting into open canopy forests as a result of potentially increased levels of mortality of larger trees due to increased tree stress in a warming climate, including potential increases in disease and pest infestation. The assumed management framework over the next 20 years would not result in a significant increase in forests with less than 40 percent canopy cover due to management limits in place that tend to minimize those conditions.
Other Land Cover
37


Total
100


a This draft 2001 and 2010 comparative assessment is awaiting further analysis.
b dbh – diameter at breast height.

Aquatic

Species
This section will be provided at a later time.
Habitat
This section will be provided at a later time.

References Cited


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[snapshot taken 7/1/2013 @0910]
[snapshot taken 7/2/2013 @0810]



Sequoia NF

Chapter 1 Composite Links
Summary | Bio-Region Introduction | Bio-Region Aquatic Ecosystems | Bio-Region Terrestrial Ecosystems | Bio-Region Riparian Ecosystems | Sierra NF | Sequoia NF | Inyo NF
Sequoia National Forest
Chapter 1: Assessing Terrestrial Ecosystems, Aquatic Ecosystems, and Watersheds

Landscape Setting


Overview

The Sequoia National Forest encompasses a broad range of habitats and elevations, ranging from blue oak woodland at 1,000 feet to alpine fell fields at over 12,000 feet. Five major biotic provinces converge on the Sequoia National Forest. Floristically, the High Sierra Nevada, Central Valley, Southern California Mountains, Great Basin Desert, and Mojave Desert all overlap here. The 1.2 million acres of the Sequoia National Forest provides a diverse range of habitats that support viable populations of a diversity of plants, wildlife and fish and wildlife, including those found only in the southern Sierra or on the Forest. The Sequoia National Forest contains the Giant Sequoia National Monument, home to the majestic Giant Sequoias. Wilderness Areas constitute approximately 28 percent (314,000 acres) of the Sequoia National Forest (Figure 1.1). The multitude of landscapes across the Forest is a result of the differences in elevation, topography, temperature, and precipitation.

The Forest can be roughly divided into three distinct ecological environments: the Greenhorn Mountains; The Kern Plateau; and the Breckenridge, Piute, and Scodie Mountains. The Greenhorn Mountains are the wettest and all of the Giant Sequoia groves are present here. To the east of the Greenhorn Mountains the Kern Plateau rises to over 9,000 feet. The Breckenridge, Piute, Scodie Mountains are islands in the midst of lowlands and are influenced by the nearby Mohave Desert (see CH1 Ecosystems - Sequoia - Brekenridge.pnginset photo). These southern mountains are drier than the Kern Plateau or the Greenhorns. In the Greenhorns, precipitation falls mainly from October through April as rain in the lower elevations and snow at the higher elevations. Winter temperatures below freezing and summer temperatures above 100 degrees indicate the normal seasonal spread.

Breckenridge, Piute, and Scodie mountains in the southern part of the Forest.




An uplifted, westward-titled Sierra Nevada block that has been deeply incised by large rivers (Wakabayashi and. Sawyer 2001), such as the Kings, Kaweah, Tule and Kern Rivers, provides a geomorphic foundation for the Forest. Volcanism also shaped the landscape; volcanic fields in the Kern and Kings Rivers were present in the Little Kern River, Domelands, and Hume Lake (Farmer et al. 2002). Great variability in aspect and slope were created by these rivers and their tributaries over millennia. Bedrock is primarily granite, along with metamorphic and volcanic presence. Terrain is dominated by steep slopes and rocky canyons intermixed with meadows, fens and riparian areas. Some areas of the Forest contain unusual rock types like limestone/marble and gabbro that create unique soil chemistry that support unique plant communities and often harbor rare plant species.

Influences of Past Management

Historic logging, livestock grazing and residential development influenced current ecological conditions and management across the landscape (McKelvey and Johnston 1992). The timber industry officially started in the southern Sierra in the mid 1800’s with sawmills located in the foothills at lower elevations near the mines they were supplying (see review in McKelvey and Johnston 1992). By the late 1800’s and early 1900’s, owners moved their sawmills to places like Hume Lake, where large diameter trees including large diameter sugar pine and giant sequoias were cut to make shakes and grape stakes (McKelvey and Johnston 1992). Flumes, roads, and other features changed the landscape. The ecology of terrestrial and aquatic systems began an additional enormous change as thousands of sheep were pastured in meadows changing soil to dust; which either blew away or washed into streams. This soil was noted as covering up swamps and meadows in 1894 (see review in McKelvey and Johnston 1992). Travelers could find no food for their horses due to the lack of herbaceous vegetation.

The Sequoia National Forest has been largely affected by fire suppression for almost a century. As a result, live and dead fuels have increased in some forest types (e.g. Westerling et al. 2006). These conditions, along with predicted warming or increased lightening during the dry season may create forests highly susceptible to an increase in frequency of large-scale, high severity fire (Long et al. 2012). CH1 Ecosystems - Sequoia - Greenhorn.pngThese past activities, combined with fire suppression since the 1920s, reduced landscape-level ecosystem heterogeneity
(see review in Collins and Skinner 2013).
This is particularly evident in current conditions with extensive areas dominated by shade-tolerant conifers, especially white fir and incense cedar. Tree encroachment has altered meadows, riparian areas, aspen clones, and other sensitive areas (see review in Long et al. 2013). Overall, this loss of heterogeneity unless remedied may detrimentally affected wildlife and plant habitat diversity, as well as reducing ecosystem resilience in the face of climate change (Thompson et al. 2009).

However, six empirical studies have been conducted in California’s forests to assess the longstanding forest management assumption that the most fire-suppressed forests (i.e., the forests that have missed the largest number of fire return intervals) burn “almost exclusively high-severity”, as the 2004 Sierra Nevada Forest Plan Amendment Final EIS (Vol. 1, p. 124) presumed. These studies found that the most long-unburned (most fire-suppressed) forests burned mostly at low/moderate-severity, and did not have higher proportions of high-severity fire than less fire-suppressed forests. Forests that were not fire suppressed (those that had not missed fire cycles, i.e., Condition Class 1, or “Fire Return Interval Departure” class 1) generally had levels of high-severity fire similar to, or higher than, those in the most fire-suppressed forests.
1)

fig 5.jpg
Figure 5 from Odion and Hanson (2006) (Ecosystems), based upon the three largest fires 1999-2005, which comprised most of the total acres of wildland fire in the Sierra Nevada during that time period (using fire severity data from Burned Area Emergency Rehabilitation (BAER) aerial overflight mapping), showing that the most long-unburned, fire-suppressed forests (Condition “Class 3+”, corresponding to areas that had missed more than 5 fire return intervals, and generally had not previously burned for about a century or more) experienced predominantly low/moderate-severity fire.
2)
fig 2.jpg

Figure 1 from Odion and Hanson (2008) (Ecosystems) (using fire severity data from satellite imagery for the same three fires analyzed in Odion and Hanson 2006), showing that the most long-unburned, fire-suppressed forests (no fire for a century or more) burned mostly at low/moderate-severity, and had levels of high-severity fire similar to less fire-suppressed forests (in one case, even less than Condition Class 1).

3) Van Wagtendonk et al. (2012) (Fire Ecology), analyzing 28 fires from 1973-2011 in Yosemite National Park, found the following:
“The propor­tion burned in each fire severity class was not significantly associated with fire return interval departure class…[L]ow severity made up the greatest proportion within all three de­parture classes, while high severity was the least in each departure class (Figure 4).”
The most long-unburned, fire-suppressed forests—those that had missed 4 or more fire return intervals (in most cases, areas that had not burned since at least 1930)—had only about 10% high-severity fire (Fig. 4 of van Wagtendonk e al. 2012).

4) Odion et al. (2004) (Conservation Biology), conducted in a 98,814-hectare area burned in 1987 in the California Klamath region, found that the most fire-suppressed forests in this area (areas that had not burned since at least 1920) burned at significantly lower severity levels, likely due to a reduction in combustible native shrubs as forests mature and canopy cover increases: “The hypothesis that fire severity is greater where previous fire has been long absent was refuted by our study…The amount of high-severity fire in long-unburned closed forests was the lowest of any proportion of the landscape and differed from that in the landscape as a whole (Z = -2.62, n = 66, p = 0.004).”

5) Odion et al. (2010) (Journal of Ecology), empirically tested the hypothesis articulated in Odion et al. (2004)—i.e., that the reduction in fire severity with increasing time-since-fire was due to a reduction in combustible native shrubs as forests mature and canopy cover increases—and found the data to be consistent with this hypothesis.

6) Miller et al. (2012a) (Ecological Applications), analyzing all fires over 400 hectares 1987-2008 in the California Klamath region, found low proportions of high-severity fire (generally 5-13%) in long-unburned forests, and the proportion of high-severity fire effects in long-unburned forests was either the same as, or lower than, the high-severity fire proportion in more recently burned forests (see Table 3 of Miller et al. 2012a).

These studies demonstrate that it cannot be assumed that the most fire suppressed forests will burn primarily at high-severity.

Greenhorn Mountains contain the Giant Sequoia Groves, and a diverse array of habitats for plants and wildlife.

In addition to the diverse environmental conditions present in the Forest, past management has helped cumulatively create the conditions of wildlife habitats that are currently present. For many habitat types within the Forest, fire or the exclusion of fire has had a significant effect on distribution, species composition, and stand structure. As a result, live and dead fuels have increased, along with the development of denser conifer forests and chaparral ecosystems to abnormally high levels of abundance, greater than the natural range of variability. However, it is important to understand that dense forest habitat, especially dense mature forest habitat, was historically abundant (see, e.g., Lydersen et al. 2013, Table 1), and is critical habitat (i.e, what the literature shows they preferentially select) for rare species like the California spotted owl, Pacific fisher, and black-backed woodpecker. The fire return interval is an indicator of how close the Forest is to the historic fire regime. The fire return interval for a given vegetation type can be used in conjunction with fire history maps to determine which areas in the Forest have missed natural fires. This information, known as the fire return interval departure (FRID) is presented in Figure 1.2. Numerous recent smaller fires and the McNally Fire are indicated by the blue areas around the Kern River Canyon indicating that the fire return interval is within normal range. Similarly in parts of the Breckenridge, Piute and Scodie Mountains the fire return interval is within normal range (Figure 1.2). Sections along the Greenhorn Mountain around 5-7,000 feet have not burned as frequently as expected under a natural fire regime.

During the last decade, Sequoia National Forest has made progress in improving and sustaining ecological heterogeneity within the natural range of variability. Some major actions include integrating more wildfire back into fire adapted ecosystems, retaining and developing large live and dead tree structures, and conducting tree thinning to develop and maintain forest heterogeneity, including opening forest canopy gaps to promote oaks, and shade intolerant pines (North et al. 2009, North 2012). Mechanical thinning, however, does not mimic natural wildfire and can eliminate or reduce the value of mature forest habitat by eliminating or reducing structural complexity (which many rare wildlife species preferentially select for). Structural complexity is key for species like the California spotted owl, Pacific fisher, and black-backed woodpecker (see, e.g., Zielinski et al. 2006, Purcell et al. 2009, Verner 1992, Bond et al. 2009). Although current management in the Sequoia National Forest is making important strides toward integrating and sustaining ecological restoration of mixed conifers, oaks and meadows, additional restoration actions, adaptive management and public involvement are needed to fully meet these ecosystem restoration goals.CH1 Ecosystems - Sequoia - Kern.png





Kern River Plateau has lush meadows, and currently plenty of water from snow-melt in its streams and meadows.





CH1 Ecosystems - Sequoia - Wilderness.png
Figure 1.1. Wilderness areas (names in legend) depicted within the Sequoia National Forest Administrative boundary (indicated by thick black line). The light purple (magenta) line depicts the boundaries of the Sequoia National Monument. The inset shows the location of the Forest in California.




















fire.jpg
Figure 1.2 Departure of the average Fire Return Interval Departure (FRID) as compared with an average historical condition for the Sequoia National Forest. The higher percentages represent the greater divergence from average reference conditions.



Terrestrial Ecosystems

Vegetation


The Sequoia National Forest encompasses a broad range of habitats and elevations, ranging from blue oak woodland at 1,000 feet to alpine fell fields at over 12,000 feet. Six major biotic provinces converge on the Sequoia National Forest and Monument. Floristically, the High Sierra Nevada, Central Valley, Sierra Nevada Foothill, Southern California Mountains, Great Basin Desert, and Mojave Desert all overlap here (Miles and Goudey 1997). The southern Sierra Nevada is a giant floristic melting pot between the Central Valley and the Mojave Desert and also between the High Sierra and the southern California Mountains (Figure 1.3). This confluence of diverse floras creates a high density of rare endemic plants and many unique plant communities.

The Sequoia National Forest can be roughly divided into three distinct environments: the Greenhorn Mountains (the southern extension of the Great Western Divide); The Kern Plateau; and the Breckenridge, Piute, and Scodie Mountains. The Greenhorn Mountains are the wettest and most productive area of the Forest. These mountains found in the Western portions of the Sequoia National Forest. Here we find all of the Giant Sequoia groves along with mixed coniferous forest (the “great green wall”) and deciduous Black Oak woodland. Because the greenhorns drop back down to 3,000 feet into the Kern River Gorge, the plant communities of the eastern slope mirror that of the western slope, including the easternmost (and most unique) Giant Sequoia groves. To the east of the Greenhorn Mountains and the Kern River Gorge, the Kern Plateau rises to over 9,000 feet. The Kern Plateau is drier and colder, because of its proximity to the Mojave and Great Basin deserts of eastern California. The Kern Plateau supports extensive stands of white and red fir forest along with the endemic southern Foxtail pine, a close relative of Bristlecone pine. The Breckenridge, Piute and Scodie Mountains are areas of dis-continuous conifer habitat totally surrounded by lowland annual grass and shrub habitat. This biologic isolation is has created unique plant communities and habitat such as Piute Cypress woodlands (see photo inset), a local endemic tree.


piute.jpg

Piute Cypress requires fire for reproduction. This is illustrated in this photograph from the Piute Mountains of an even age stand resulting from fire 80 years ago.









Foothill Zone

The foothill ecological zone occurs at the lowest elevations and is comprised of chaparral, blue oak savannahs, live oak woodlands and forests, narrow riparian stringers along rivers and streams, seeps, and scattered pine (Barbour et al. 2007). Overall, the vegetation and fire patterns in this zone are outside of the range of variability (Estes 2013, Merriam 2013, and Sawyer 2013). The foothill zone of the Forest captures a small proportion of the western foothill belt which is mostly in private ownership throughout the Sierra Nevada (Britting et al. 2012). Nineteenth century livestock g razing is considered to be the primary factor in changes in the blue oak foothill woodlands (Vankat and Major 1978). Vegetation is mostly out of the natural range of variability as a result of persistent non-native species, urbanization, water development, changed fire regime, and agricultural uses. Because of these factors, the small amount of this biologically diverse vegetation type that is in public ownership is disproportionately important for long-term conservation. This vegetation zone falls within Sierra Nevada Ecological Section Sierra Nevada Foothills in the USDA Forest Service National Hierarchical Framework of Ecological Units (Figure 1.3, Miles and Goudey 1997).

Tree-dominated plant communities are blue oak (Quercus douglasii) woodland or savannah, with foothill pine (Pinus sabiniana), California buckeye (Aesculus californicus), and interior live oak (Quercus wislizenii) present to varying degrees. Other tree-dominated types in the foothills are foothill pine and valley oak forests. Within the Sequoia National Forest, as is typical for the Southern Sierra Nevada, the understory biomass is dominated by non-native grasses while paradoxically native herbaceous and shrub species diversity is high. Non-native annual grasses include brome (Bromus spp.), wild barley (Hordeum sp.), wild oats (Arena spp.), and annual fescues (Festuca myuros) (Parsons and Stohlgren 1989).

Trends
Although a valued system, oak woodlands are located in areas highly valued for other uses, resulting in conflicts. Blue oak woodlands in the western Sierra Nevada display considerable fragmentation. Oak woodlands largely exist on private lands (>90%), where conflicts with agriculture (Jimerson and Carothers 2002), grazing, water use and development exist. Increased urbanization in the Southern Sierra will lead to increased pressures on oak woodlands unless ecological land use complementation is employed (Colding 2007). Overall exposure of blue oak to climate change is expected moderate to high by late century (Kueppers et al. 2005). Warmer temperatures, decreased precipitation and wildfire would all be important in a northward range shift (Kueppers et al. 2005). The effects of climate change projected to 2070 forecast increases of blue oak (Quercus douglasii)/foothill pine (Pinus sabiniana) in the Sierra Nevada ecoregion (23 to 97%) (Gardali et al. 2011). Some oaks may benefit from climate change in the short term, given that mature trees are generally drought and fire resistant. Although not currently exposed, oaks are sensitive to both insects and disease (Jimerson and Carothers 2002, Rizzo and Garbeletto 2003), which may become significant in the future. Seedlings and saplings, however, are sensitive to soil moisture and precipitation, affecting the long-term vulnerability of the oak woodland system. Predation of saplings by cattle and deer (Adams and McDougald 1995,Hall et al. 1992) reduced oak recruitment and increases vulnerability in the long-term. Modern oak understories are dominated by nonnative European annuals (Roche et al. 2012). Due to the rapid onset of climate change, plants and animals associated with oak woodlands must move to higher elevations or northward or be extirpated (Loarie et al. 2009). Stressors include fire, grazing, pollution, and climate change. These stressors could potentially alter these communities (NPS 2013). While disturbances like fire are natural, frequency and intensity of fires outside their historic range of variation may cause a change in vegetation type (NPS 2013).


Figure 1.3. Ecological Sections within California ; the Forest is influenced by High Sierra Nevada (beige), Sierra Nevada Foothill (brown), Central Valley (cream), Southern California Mountains (Orange), and the Mohave desert (pink).
CH1 Ecosystems - Sequoia - EcoSections.png

Montane Zone

Ponderosa pine, black oak, mixed conifer, riparian forests, chaparral and meadows comprise the vegetation mosaic in the west-side montane zone (Fites-Kaufman et al. 2007). The lower and mid-elevation mixed conifer forest on the western slopes of the Sierra occurs from 1000 to 1,500 m at its lower margin to 3,000 to 3,500 m at its upper limit. Black oak is important throughout the lower elevations of the lower montane forests (Fites Kaufman et al. 2007). In the Greenhorns and Kern Plateau, Jeffrey pine (Pinus jeffreyi), incense cedar (Calocedrus decurrens), and white fir (Abies concolor) are common. Sugar pine (P. lambertiana) used to be a dominant conifer but is rare or absent (Fites Kaufman et al. 2007). The upper montane zone comprised of a mosaic of conifer forest, meadows, and montane chaparral. On the western slopes red fir (Abies magnifica), Jeffrey pine (Pinus jeffreyi), and lodgepole pine (Pinus contorta subspecies murrayana) are the dominant forest species (Fites – Kaufman et al. 2007).


Special Habitats


There are some habitats that are less common, yet support a high level or specialized type of biodiversity. Information is often limited on these habitats but they are important to include. While not an exhaustive list, some of the special habitats noted on the forest include: old forest, complex early seral forest, rock outcrops, and Giant Sequoia groves. There are other riparian or wetland associated habitats, including fens and aspen, which are discussed later. The Giant Sequoia groves occur throughout the Greenhorn Mountains and across the Sequoia National Park to the Hume Lake District and into the Sierra National Forest. The Sequoia National Monument contains the giant sequoias and their watersheds on the forest. Further discussion is not included here because they were addressed in the recent Giant Sequoia National Monument Plan.

Rock outcrops support a variety of uncommon and often rare plants. These include limestone, metamorphic, gabbro, and granite rock outcrops. Plants associated with these habitats are described in Chapter 5. These areas are impacted by invasive plant species, habitat fragmentation, uncharacteristically frequent fire, surface mining, post-fire disturbance (e.g., intensive grazing), illegal marijuana cultivation, and climate change.


Aspen is a broad-leaved tree that occurs in diverse habitats on the Sequoia National Forest, from wet areas to subalpine rock talus. It occurs most commonly around meadows and streams in the upper montane red fir and lodgepole pine forests. Although it currently encompasses less than 1% of the assessment area, it supports very diverse understory plant and bird communities. Several bird species of management interest are associated with aspen including Northern Goshawk, Red-breasted Sapsucker, Warbling Vireo, and Mountain Bluebird. Aspen distribution is greatly reduced compared to pre-European settlement, and many stands are in poor condition due to conifer encroachment and poor regeneration. Estimates suggest its extent in western North America has been reduced by as much as 96%, primarily because of fire suppression and historic overgrazing. Fire is also important in aspen stands because it kills young conifers that shade out light-loving aspen. Mule deer uses aspen stands to feed and cover for fawning. Grazing by domestic livestock, sheep and cattle, increased dramatically in the mid-1800’s and had a dramatic effect on aspen and meadows in general. Aspen sprouts, or regeneration, are favored browse. Reduction in aspen regeneration was noted in the early 1900’s (Sampson 1919). Fencing can result in higher aspen sprouts. In the intermountain west, decreased aspen growth has already been attributed to higher temperatures and extended drought. Annual fluctuations in available soil moisture resulting from El Niño influences on snow pack depth may have a significant influence on establishment of plants.


After moderate to intense fire early seral habitat is formed. If, across the landscape patchiness of habitat were maintained all species dependent on old growth and early seral habitat could be maintained across the landscape. However, fire suppression has suppressed these landscape level processes of habitat creation and succession. If in the past fire, drought, and wind combined to create openings in the canopy, patches of early seral habitat would have been created across the landscape. Without fuels management and a return of controlled fire to the landscape the patchy nature




Trends:
Composition, structure, and fire regimes have changed considerably since pre-settlement times (Van de Water and Safford 2011), and are largely outside the natural range of variability in the Greenhorn Mountains. Pines and oaks have decreased substantially and shade tolerant species, such as cedar and fir, have increased. White pines across the Sierra Nevada are currently threatened by a combination of factors including outbreaks of native and exotic insects and diseases, altered fire regimes, air pollution, and climate change (NPS 2013). Forest density is higher, canopy cover of trees more uniformly higher, small and medium tree density is higher and large tree density is lower. Within stand variation in tree size and density has decreased. Drought has triggered tree mortality in mixed conifers (Guarin and Taylor 2005); and large tree mortality has doubled in the last 2-3 decades across the West (van Mantegem et al. 2009). This pattern is associated with increases in temperature and droughts, rather than fire history, stand density or insects (Briting et al. 2012). Also, the raw data in van Mantgem et al. (2009) (obtained directly from the authors) do not indicate a reduction in large trees (e.g., those 60-90, or >90 cm dbh) in Yellow Pine/Mixed Conifer over time in Sierra Nevada forests, and the largest size class category presented in van Mantgem et al. (2009) was >40 cm dbh (i.e., over 16 inches dbh). The van Mantgem et al. (2009) data are consistent with old stands self-thinning their understories in the long absence of significant fire. Based on growth rates of Giant Sequoias over a 2089 year record, the last one hundred years has had below average frequency of drought (Hughes and Brown 1991).The Giant Sequoias are particularly vulnerable to climate change, because wetter areas they depend on are expected to shrink.

Subalpine and Alpine Zones

Coniferous forest types within this zone are upper coniferous forest dominated by red fir and lodge pole pine, with an increasing component of western white pine (Pinus monticola) and some stands of mountain hemlock (Tsuga mertens