Inyo National Forest
Chapter 1: Assessing Terrestrial Ecosystems, Aquatic Ecosystems, and Watersheds


11/18/2013: The Inyo National Forest's Draft Assessment Report is available for review through 12/16/2013. Click here to visit the forest's planning webpage for the Draft Assessment Report and the finalized topic papers.

6/12/2013: Inyo National Forest Extends Public Review Period For Forest Plan Revision Topic Papers through September 1, 2013. It was previously announced that the topic papers were available for public review and feedback through June 30, 2013.

5/31/2013: A snapshot of the topic papers was taken on 5/7/2013 and PDF versions with graphics are available on the Inyo NF Planning website http://www.fs.fed.us/nepa/fs-usda-pop.php/?project=40601. Note the current content in this chapter may differ from the snapshot PDF versions.

5/23/2013: If you would like to receive copies of the Draft Natural Range of Variability Analyses (Draft NRVs) referenced in Chapter 1, please email jetapia@fs.fed.us for a copy.

5/3/2013: The draft topic paper for the Inyo’s Chapter 1 has been loaded to the Living Assessment! Topic papers for this and other Inyo National Forest assessment chapters will be available for public review and feedback through September 1, 2013 (Note: If you’d like to review the annotated outline for Chapter 1 it is still available on our website at http://www.fs.fed.us/nepa/fs-usda-pop.php/?project=40601.)

Please contact Deb Schweizer, Public Affairs Specialist, at (760) 873-2427 or debraaschweizer@fs.fed.us for more information about forest plan revision for the Inyo National Forest.

This chapter addresses the terrestrial, aquatic, and riparian ecosystems on the Inyo National Forest (Inyo NF, or the Forest). It describes the overall character of the Forest, and provides the ecological context for the many different ecosystems found here. The current condition and trend of each ecosystem is discussed, utilizing the best available scientific information.

Terrestrial Ecosystems

Introduction

The Inyo NF is truly a land of superlatives: the oldest living trees on the planet, the highest peak in the contiguous United States, the youngest mountain range in North America, and one of the oldest lakes in North America. Three major biotic provinces – the Sierra Nevada, the Great Basin, and the Mojave Desert - converge in this unique area. Geologic formations and rock types include volcanic craters, basalt flows, layers of ash and pumice, carbonate formations, and granite peaks, walls, and spires. With elevations ranging from approximately 1,160 to 4,418 meters (3,800 to 14,495 ft), this sets the stage for a wide variety of ecosystems, supporting in turn unique wildlife and plant species and a high level of biodiversity.

Several hierarchical systems exist for describing ecosystems at varying scales. This assessment relies on the Forest Service National Hierarchical Framework, consisting of domains, divisions, provinces, sections, and subsections. The Inyo National Forest lies within 3 ecological provinces as delineated by Bailey (1994): M261 Sierran Forest – Alpine Meadow, M341 Intermountain Semi-Desert and Desert, and M322 American Semi-Desert and Desert.

These 3 provinces include 4 sections, and 12 subsections nested within the larger provinces (Miles and Goudey 1997) (see table below). Ecological subsections are areas with similar surficial geology, lithology, geomorphic processes, soil groups, subregional climate, and potential natural communities.

Table 1. Ecological hierarchy, including province, sections, and subsections.
Province
Section
Subsection
M261 – Sierran Forest – Alpine Meadows
M261E – Sierra Nevada Section
M261Er – Eastern Slopes


M261Eo – Glaciated Batholith


M261Eu – Kern Plateau
M341 – Intermtn Semi-Desert and Desert
M341D – Mono Section
M341De – Bodie Hills-Excelsior Mountains
M341Df – Mono Valley
M341Dh – Crowley Flowlands
M341Di – Benton – Upper Owens Valleys
M341Dj – White Mountains
M341Dl – Glass Mountain
M341F – Southeastern Great Basin Section
M341Fa – Silver Peak Mountains-Fish Lake Valley
M341Fb – Inyo Mountains
M322 - American Semi-Desert and Desert
M322A – Mojave Desert Section
M322Aa – Owens Valley

The eastern Sierra is known for its large expanses of undeveloped land. Other major land managers in the region include the Bureau of Land Management (BLM) and the Los Angeles Department of Water and Power (LADWP). There are no large tracts of land that are currently subject to development pressures. The communities within and adjacent to the Forest are relatively small and discrete, i.e. limited sprawl exists, so connectivity between the Forest and similar ecosystems on adjacent lands is relatively intact with regard to development. The Forest is also relatively intact with regard to interior land ownership, i.e. the “checkerboard” pattern that is common on some Sierra Nevada Forests is limited on the Inyo NF. The majority of the Forest boundaries are at the lower and upper elevational limits of the Forest.

The Inyo NF shares boundaries with Sequoia-Kings Canyon, Yosemite, and Death Valley National Parks, Devils Postpile National Monument, BLM, LADWP, and private entities, as well as other National Forests.

For the purposes of this topic paper, the ecosystems addressed in this assessment are derived from the Forest Terrestrial Ecological Unit Inventory (TEUI) Ecological Types, with several ecological types combined into one of 10 “assessment types”:
  1. Pinyon-Juniper
  2. Sagebrush Shrub
  3. Subalpine Conifer
  4. Jeffrey Pine
  5. Red Fir
  6. Mixed Conifer
  7. Mountain Mahogany
  8. Xeric Shrub and Blackbrush
  9. Alpine
  10. Special Types (aspen, dry forb, and alkali flats).

Each assessment type may include several different vegetation communities. For this reason, the assessment types do not necessarily portray each individual vegetation community as it occurs on the ground. For example, in looking at the red fir assessment type, one may find Jeffrey pine, mixed conifer, and pinyon-juniper areas that actually occur within the mapped red fir assessment type. Appendix A provides a list of which TEUI ecological types are included in each assessment type.

In addition to the ecological assessment types listed in Appendix A, there are special terrestrial plant communities on the Forest that can only be addressed at a finer scale than the assessment types. These ‘special types’ represent an important component of biodiversity, and include alkali flats, dry forb, and aspen. These are discussed individually in the Special Types section within this assessment.

Riparian vegetation is a critical component of biodiversity, and is discussed under the Riparian Ecosystems section. Riparian special types, such as fens, are also included in the Riparian Ecosystems section.

Process and Methods

Scale of Assessment
This assessment is conducted primarily at the Forest scale. Where ecosystems, including ecosystem processes, cross Forest boundaries onto adjacent lands, the condition and trend of the ecosystem on those lands will be considered as it relates to the condition and trend of that ecosystem on Forest lands, and vice versa.

This assessment addresses ecosystems at a coarse scale, utilizing the assessment types described above. In addition, certain unique ecosystems will be assessed at a more localized finer scale, due to their limited distribution across the landscape.

Where ecosystems and/or issues may be more appropriately reviewed at a bioregional scale they will be addressed as such, or the Bioregional Assessment will be referenced.

Indicators used to assess ecosystem integrity will be analyzed at the landscape scale, the community scale, and/or multiple scales, as needed to portray ecosystem condition. Data for the indicators will continue to be gathered and analyzed throughout the assessment and planning phases of Forest Plan Revision.

Information Sources
This assessment draws primarily from information in the Natural Range of Variability (NRV) analyses conducted by the Regional Ecology Program and the Science Synthesis (Long et. al. 2013), as well as the draft Bioregional Assessment topic papers.

This Forest assessment uses Miles & Goudey’s Ecological Subregions of California as the underlying basis for describing ecosystems.

The primary source of specific ecological information, e.g. amount and distribution of assessment types, and detailed information for the assessment types related to composition, structure and function of each type, is the Forest Terrestrial Ecological Unit Inventory (TEUI) (USDA INF 2012a), particularly the Potential Natural Vegetation (PNV) component of the TEUI. In most parts of the Forest, the PNV is not significantly different from the current vegetation, at least with regard to which vegetation series occupies a given area. Over 300 ecology plots were completed across the Forest to inform the TEUI, encompassing all assessment types. Data from these plots is used to derive values for the various indicators for each assessment type, and for the larger landscape across the Forest.

Forest Inventory and Analysis (FIA) data and Existing Vegetation data (E-veg) from the Forest Service Remote Sensing Lab are used in the Bioregional Assessment Chapter 1 topic paper; however, at the Forest scale, the TEUI provides a more accurate picture of the relative abundance and condition of the ecosystems found here. E-veg is an existing vegetation layer developed across all lands by the U.S. Forest Service in coordination with the California Department of Forestry and Fire Protection’s Fire and Resource Assessment Program (FRAP). There may be particular indicators of certain assessment types, e.g. structural components of mixed conifer forest that may be better represented by these regional datasets. These are used as appropriate on a case by case basis.

Indicators
Indicators have been chosen to describe ecosystem conditions in the assessment, to follow through the analysis process in the assessment and National Environmental Policy Act (NEPA) phase; and later on, for monitoring.

The selected indicators are measurable (at least qualitatively), and are focused on those elements we have some type of data for. Indicators may be used for one or more assessment types and/or for all types across the Forest, depending on available information, and potential concerns. The Current Conditions and Trend section below includes indicators for the entire Forest, and indicators that are specific to each assessment type.

Current Conditions and Trend

As outlined in the Introduction section, the Inyo National Forest is highly diverse in geology, elevation, floristic influences, climate, and hence, ecosystems. In the following table, each assessment type is displayed in terms of acres and proportion of forest to display the relative influence of different assessment types across the landscape.

Table 2. Coarse scale biodiversity
Assessment type
Acres
Proportion of Forest by assessment type
Pinyon-juniper
561,022
28%
Subalpine conifer forest
383,336
19%
Sagebrush
308,410
15%
Xeric shrub and blackbrush
213,722
11%
Jeffrey pine
135,086
7%
Alpine
129,805
6%
Red fir
118,039
6%
Mountain mahogany
81,655
4%
Mixed conifer
45,671
2%

Table 3. Fine scale biodiversity
Special type
Acres
Proportion of Forest by special type
Aspen
12,986
0.6%
Dry forb
11,579
0.6%
Alkali flat
9,376
0.5%

Table 4. Drivers and Stressors, forestwide scale
Attribute being measured
Indicator
Measure or Unit
Value
Fine scale biodiversity
Total proportion of Forest occupied by special types, including riparian
Percent
3%
Ecosystem function - invasives
Area occupied by invasive species
Acres - NRIS
34,668
Ecosystem function - fire
Proportion of landscape within FRCC classes (No values associated with this indicator. Percentage by class by veg type should be included).
Percent by class


As pointed out in the Introduction section, to address the ecological systems across the Forest the scale of the assessment types is necessarily coarse. For example, a given area mapped as the Jeffrey pine assessment type may actually be dominated by mixed conifer, lodgepole, and/or other vegetation communities on the ground, but overall, Jeffrey pine is the dominant vegetation within that assessment type. Finer scale information can be accessed for project-level analyses.

The Bioregional Assessment Chapter 1 topic paper also provides information on the vegetation patterns on the Inyo NF utilizing the E-veg layer and California Wildlife Habitat Relationships (CWHR) types. CWHR types are broad categories of habitat based upon dominant plant species, density, and average size of trees or shrubs. Maps are provided in the Bioregional Assessment Chapter 1 topic paper for the East-South Subregion, which includes the Inyo NF. The following information is displayed: terrestrial ecosystem types, percent lifeform, density, and average tree diameter.

Drivers and stressors, such as climate, fire, insects and disease, and air pollution, that play a role in ecosystem function on the Inyo NF are identified in Chapter 3, and are discussed further below where they vary between specific assessment types. The Bioregional Assessment Chapter 1 topic paper summarizes potential vegetation changes in the bioregion due to current or potential changes in climate. The common view overall is that changes will be greatest at the boundaries between different vegetation types, with a general upward migration of vegetation types or species and shrinking of higher elevation or upper montane and subalpine zones. There is uncertainty about what the changes in climate will be, how those changes will affect vegetation, and how fast vegetation changes will occur.

The remaining portion of this discussion of current conditions and trend will be organized by assessment type to better display the status of ecological integrity for each type. For additional detail on pinyon-juniper, sagebrush, subalpine conifer forest, red fir, mixed conifer, and Jeffrey pine, refer to the Natural Range of Variability (NRV) analyses for each of these types.

1) Pinyon-Juniper Assessment Type
Current Conditions
Pinyon-juniper, including the various subcategories within this type, is the most extensive assessment type on the Forest, covering over 500,000 acres. Pinyon-juniper woodlands are prevalent along the escarpment of the Sierra Nevada, as well as at mid-elevations in the White, Inyo, and Glass Mountains. The pinyon-juniper assessment type includes stands of pure pinyon pine, as well as pinyon intermixed with Utah juniper, canyon live oak, mountain mahogany, and other tree and shrub species (see Appendix A).

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of pinyon-juniper woodlands across the Forest.

Table 5. Indicators for pinyon-juniper assessment type. (In all tables that are indicators by vegetation assessment type - an additional row for ecosystem function - fire should also include habitat created (early seral, mid seral, late seral).
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ratio shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Densification
Overstory density
Tree density by size class
FIA
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
Number of species
TEUI
Ecosystem function - erosion
Proportion bare soil
Percent bare soil
TEUI
Ecosystem function – soil crusts
Cover of soil crusts
Percent cover
TEUI
Ecosystem composition – invasive species
Number of invasive species
Count
NRIS
Ecosystem function – invasive species
Extent of invasives
Acres occupied
NRIS
Ecosystem function – invasive species
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres, 10 year intervals
Forest fire history layer?

Some of the areas on the Forest currently classified as pinyon-juniper woodlands include sagebrush shrub communities that have experienced an increase in pinyon and/or juniper trees over the past several decades or longer. Tausch and others have classified the stages of increase in tree density into 3 phases where Phase I is still dominated by shrubs, trees and shrubs are co-dominant in Phase II, and in Phase III trees are dominant and typically the understory is very limited or non-existent (Tausch, Miller et al 2009, cited in Stone 2013). This “encroachment” is due to a combination of factors that may include grazing, fire suppression, and/or climate changes, among others, and the consequent effects on fine fuels, nutrient cycling (soil crusts), and community structure and composition. According to the NRV assessments regarding pinyon-juniper expansion into sagebrush shrubland (Slaton 2013; Stone 2013), the current distribution of pinyon-juniper is greater than during the NRV period, though part of this expansion may be continued adjustment to Holocene climate changes. Conversely, part of the expansion is likely due to changes in fire regime associated with removal of herbaceous fuels by historic livestock grazing, as well as with fire suppression.

Certain landforms in this type are less affected by human and/or climate-induced changes; specifically, pinyon-juniper types on more xeric, convex sites, e.g. steep rocky slopes and ridges vs. more gently sloping valleys and other more mesic sites with deep soils. These xeric sites are termed “persistent woodlands” in the pinyon-juniper NRV discussion, and are generally within NRV with regard to fire regime. The “wooded shrublands” of the pinyon-woodland NRV discussion include those areas, typically on more mesic gently sloping settings, where pinyon-juniper has advanced into sagebrush shrublands. Per the more detailed discussion in the NRV analysis, pinyon-juniper has moved up- and downslope and onto more mesic productive sites previously occupied by sagebrush steppe throughout the Holocene in response to changes in climate. It is unclear how much of the current ongoing change in this system is due to climate and how much is due to anthropogenic alteration of disturbance regimes, particularly through livestock grazing and trampling, and fire suppression. See Chapter 3, and the sagebrush and pinyon-juniper NRV discussions for more detail regarding the interaction between grazing, fire, and climate in pinyon-juniper and sagebrush ecosystems.

The BLM has begun treatment of pinyon juniper woodlands to reduce tree density in selected areas. A few thousand acres have been treated to date, over the past 10 years.

Non-native invasive plant species (NNIS) are a significant threat to pinyon-juniper woodlands on the Forest, as well as on adjacent lands throughout the range of this ecosystem. The degree of infestation varies between different settings and geographic areas. Approximately 9,000 acres (less than 2%) within the pinyon-juniper assessment type are occupied to some degree by non-native plant species. There are 13 different non-native species known to currently occur within this type. Acreages reported in this assessment are rough estimates based on existing information regarding species locations. Most areas on the Forest have not been mapped. In addition, the density of invasive plant species across the areas where they occur vary widely, from a few sparsely scattered individuals to areas where a significant portion of the vegetation cover is made up of invasive species.

Cheatgrass (Bromus tectorum) is by far the most abundant invasive species in the pinyon-juniper assessment type; indeed, it is the most common invasive plant species across the Forest as a whole. Red brome (Bromus madritensis var. rubens) is also not uncommon within the pinyon-juniper type. Halogeton (Halogeton glomeratus) is found along roadsides and in disturbed places. Invasive species can displace native species within pinyon-juniper woodlands, impacting biodiversity, soil stability, and wildlife habitat. Changes in the abundance and distribution of non-native annual grasses can also lead to significant changes in fire regime, potentially resulting in eventual type conversions from woodland to non-native annual grassland.

Several moderate to large wildfires have occurred within the pinyon-juniper assessment type on the Forest in the relatively recent past, including the Forks (2009, 2,811 acres), Clover (2008, 15,789 acres), Sawmill (2006, 7,437 acres), and Birch (2002, 2,549 acres) fires. These areas have seen an increase in cheatgrass density and distribution following the fire events.

A wide variety of past and current management activities and/or natural processes have affected the current condition of pinyon-juniper ecosystems on the Forest. These include but are not necessarily limited to livestock grazing, fire suppression, wildland fire, fuels treatment, mining, various special uses, and recreation uses including campgrounds, off-highway vehicle (OHV) activity, hunting, etc.

Impacts from these activities include, but are not limited to, direct removal of vegetation, changes in vertical and/or horizontal structure within the existing vegetation, soil compaction, erosion, fragmentation, and reduced biodiversity due to competition from invasives.

Pinyon-juniper is the target element for the Whippoorwill Flat Research Natural Area (RNA). The pinyon-juniper assessment type also occurs within the White Mountain RNA. RNAs are managed to maintain biological diversity and provide ecological baseline data, education and research, so they typically are less affected by human uses. Only non-manipulative research is allowed in an RNA. None of the RNAs on the Forest have known invasive plant species at this time; however, unrecorded occurrences may exist. See Chapter 15- Designated Areas, for more information on RNAs, including information specific to Whippoorwill Flat and other RNAs on the Forest.

Approximately one third (183,611 acres) of the pinyon-juniper assessment type is located within wilderness, where management activities are more limited; however, grazing, fire suppresssion and other drivers and stressors (invasives, climate, air pollution, etc.) of this ecosystem do continue to affect conditions within wilderness.

Trends
Climate, invasive species, fire suppression and grazing are likely the most significant influences on the trend of pinyon-juniper ecosystems on the Forest, as well as throughout the western United States. Fluctuations in the extent and condition of this ecosystem, particularly with regard to tree density and associated herbaceous and/or shrub understory, are occurring at present, and are likely to continue. Changing climate and/or more direct anthropogenic influences (fire suppression, grazing, introduction of invasives, creation of environments more favorable to invasives) each play a significant role in this dynamic landscape.

Even with the implementation of projects to slow or halt the expansion of this assessment type into sagebrush shrublands, management is unlikely to be able to keep pace with the continued expansion of the pinyon-juniper type, particularly the expansion that is related to a warming climate.

Invasive species, non-native annual grasses in particular, are likely to continue to increase in extent and abundance without significant efforts targeted at treatment and prevention. Even with significant effort, this trend will likely continue.

Climate change and other large scale stressors such as air pollution are discussed in greater detail in Chapter 3, and will not be addressed at length in this section.

2) Sagebrush Shrub Assessment Type
Current Conditions
Sagebrush shrub is another very prominent assessment type on the Forest, occupying approximately 300,000 acres. This acreage does not include those areas currently occupied by pinyon-juniper that could potentially be a sagebrush shrub type (see pinyon-juniper discussion above). The sagebrush shrub type, for the purposes of this assessment and in keeping with the NRV analysis for sagebrush, includes all subspecies of big sagebrush (Artemisia tridentata), as well as the other woody sagebrush species found on the Forest, and shrub communities where sagebrush is dominant but other species co-occur, e.g. low sagebrush, sagebrush-bitterbrush, black sagebrush, silver sagebrush, etc. (see Appendix A). Sagebrush shrub communities occur from the floor of the Owens Valley on LADWP lands, in disjointed bands all the way up to and including subalpine areas in the Sierra Nevada, and the ‍‍‍‍White‍‍‍‍, Inyo, and Glass Mountains.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of sagebrush shrublands across the Forest.

Table 6. Indicators for sagebrush shrub assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ratio shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Pinyon encroachment
Overstory density
Tree density by size class
FIA
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
Number of species
TEUI
Ecosystem function - erosion
Proportion bare soil
Percent
TEUI
Ecosystem function – soil crusts
Cover of soil crusts
Percent cover
TEUI
Ecosystem function – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres
Forest fire history
Stressors – grazing
Amendment 6 condition classes
Condition class (Excellent, Good, Fair, Poor)
Forest range monitoring

Past and current management activities and/or natural processes that have affected the current condition of sagebrush ecosystems on the Forest are similar to those for the pinyon-juniper assessment type on the Forest, though mowing shrubs for fuels reduction is more common in the sagebrush type. Similar activities occur on adjacent sagebrush lands managed by the BLM and LADWP. OHV recreation tends to be more common on sagebrush and xeric shrub lands immediately adjacent to established communities, where route proliferation has occurred over the past 10 to 20 years. Bouldering has become increasingly popular over the past couple of decades, bringing more recreationists to the area during the “shoulder seasons”, resulting in an increase in dispersed camping in the sagebrush, xeric shrub, and pinyon-juniper types on the Forest.

As discussed above for the pinyon-juniper assessment type, some of the area on the Forest currently occupied by pinyon-juniper woodlands includes sagebrush shrub communities that have experienced an increase in pinyon and/or juniper trees over the past several decades or longer due to natural and anthropogenic causes. Jeffrey pine is also encroaching into sagebrush shrub areas on the Forest. Hence, some of the same factors that are primary influences on the current condition and extent of the pinyon-juniper assessment type are likewise primary influences on the current condition and extent of the sagebrush shrub type. Due to differences in site characteristics, grazing history, and fire history, this pertains primarily to vegetation series where one or more subspecies of big sagebrush (Artemisia tridentata) is the dominant or co-dominant shrub species. Reigel et al 2006) report that in the fuel-limited low sagebush (A. arbuscula) and black sagebrush (A. nova) communities, fire return intervals were commonly greater than 150 years. The NRV analysis for sagebrush also notes that low sagebrush and black sagebrush have a lower fire return interval than big sagebrush, these communities being smaller in stature than big sagebrush, as well as less productive and more widely spaced (Young and Evans 1981, Miller and Rose 1999, Baker 2006, all cited in Slaton 2013). Rothrock (A. rothrockii) and silver sagebrush (A. cana ssp. bolanderi) are often considered as woody invasives in meadow systems on the Forest, and are generally present in systems where meadow hydrology has been altered.

The Inyo NF has treated approximately 600 acres to improve the condition of sagebrush ecosystems on the Forest by removing or Jeffrey pine while they are still in very low densities, specifically in the upper Owens River area. Another 200 acres are proposed for treatment in the near future. Habitat conditions for sage grouse are a primary consideration in these projects.

Recent wildfires that have burned at least partially within the sagebrush assessment type include the Mono (2010, 1,204 acres), Oak (2007, 27,073 acres), Sage (2007, 6,462 acres), Fuller (2002, 6,432 acres) and McLaughlin (2001, 2,714 acres) fires. As in the pinyon-juniper fires, cheatgrass has increased in many of these areas following fire.

More than 11,000 acres of the sagebrush assessment type on the Inyo NF currently have a record of at least one non-native plant species. There are sixteen non-native species known to occur in this type on the Forest. Cheatgrass, referred to in the pinyon-juniper discussion, is a significant stressor to sagebrush shrublands on the Forest and on adjacent lands; indeed, throughout the West, sagebrush ecosystems are the most at risk of degradation from and even complete loss to cheatgrass invasion. The degree of infestation varies between different settings and geographic areas, as well as between different sagebrush series within the sagebrush shrub assessment type. The greatest threat from cheatgrass is the potential for type conversion from sagebrush shrub to invasive annual grassland as a result of increasingly frequent fires. This is most pronounced in the big sagebrush communities. Fortunately, to date there have been no complete type conversions to cheatgrass on the Inyo NF, as has occurred in parts of Nevada and Utah. Past heavy livestock grazing has impacted mycorrhizal soil crusts in sagebrush ecosystems in the West (Belnap et al 2001 cited in Slaton 2013), helping to create an environment more conducive to the estalishment and spread of invasive plant species.

Fifty-eight vegetation condition transects have been conducted on livestock allotments over the past decade in the sagebrush assessment type on the Forest. These were in sagebrush, bitterbrush, and mixed types. Of the 58 transects, 35 were rated as being in excellent vegetation condition, 13 were rated good, 10 were fair and -0- were poor. Since these transects are focused on range monitoring, they are not necessarily representative of the sagebrush assessment type on the Forest as a whole.

Road density may have an impact in some areas within the sagebrush type. The removal of vegetation cover, soil compaction, and the introduction and spread of invasive species are some of the effects of roads on the sagebrush ecosystem, of particular concern where road density is high.

Sagebrush is not a target element in any of the RNAs on the Forest. The sagebrush assessment type does lie within the boundaries of the White Mountain, McAfee Meadow, and Indiana Summit RNAs. Based on the finer scale mapping of the ecological surveys conducted specifically for the RNA program (Keeler-Wolf 1990), there are also small areas of the sagebrush shrub vegetation type within the Whippoorwill Flat and Sentinel Meadow RNAs. See Chapter 15 – Designated Areas for more information about RNAs.

Approximately 30% (89,894 acres) of the sagebrush assessment type on the Inyo NF is located within designated wilderness.

Trends
Similar to the pinyon-juniper assessment type, climate, invasive species, fire and grazing are likely the most significant influences on the trend of sagebrush ecosystems on the Forest, as well as throughout the Western United States. Under the current Forest Plan, the Inyo NF will continue to manage for sage grouse habitat, but projects will likely not keep pace with the expansion of woodlands into the sagebrush type.

The current Forest Plan, particularly the Sierra Nevada Framework (2004) encourages pro-active management of invasive species; however, budgets have been inadequate to successfully address the issue. This is likely to continue into the future. It is highly likely that non-native invasive annual grasses will continue to spread through the sagebrush ecosystems on the Forest, particularly following fires and with a warming climate. Finch (2012, cited in Slaton 2013) predicts that drought, megafires, pests, and non-native invasions will increase over the next century in arid shrublands in the bioregion, and that cheatgrass in particular is expected to continue to move northward and upward in elevation.

Development of wind, solar, and geothermal energy can be expected to increase in the coming years, potentially resulting in additional impacts to sagebrush ecosystems on the Forest. Expansion of existing geothermal production is currently proposed with potential impacts to the sagebrush shrub and Jeffrey pine assessment types.

3) Subalpine Conifer Forest Assessment Type
Current Conditions
The subalpine conifer forest assessment type includes several distinct vegetation series, including whitebark pine, limber pine, foxtail pine, Great Basin bristlecone pine, lodgepole pine, western white pine, and mountain hemlock, as well as various combinations of these (see Appendix A). As such, it occupies a significant portion of the Forest, encompassing almost 400,000 acres in the Sierra Nevada, White, Inyo, and Glass Mountains. These forests are characterized by prolonged winter snowpack, a short growing season, and cool summer and cold winter temperatures. Subalpine conifer forests occur as forests with relatively high canopy cover, as well as woodlands, with more open stands and relatively low canopy cover.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of subalpine conifer forests across the Inyo National Forest.

Table 7. Indicators for subalpine conifer assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Heterogeneity
Variation in canopy cover, tree diameters, tree density
Variance among plots
FIA
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ration shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Structural complexity
Overstory density
Tree density by size class
FIA
Connectivity, fragmentation
Patch size
Acres – average and range
FIA
Special components
Snags & down woody debris
#/acre, tons/acre by size and decay class
FIA
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem composition – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres, 10 year intervals
Forest fire history?

With the possible exception of lodgepole pine, subalpine forests, due at least in part to their relative inaccessibility, have been less influenced historically by human activities than lower elevation types such as sagebrush, pinyon-juniper, and Jeffrey pine; however, effects are evident from natural processes and human activities, including fire management, climate influences, timber management, and recreation uses, among others.

Insect outbreaks - mountain pine beetle in particular – have affected areas of the subalpine conifer forest periodically throughout time, well before the period of European settlement in the Sierra Nevada. These outbreaks typically increase during times of drought, or in conjunction with other events or conditions that stress the trees in these systems. Mortality associated with mountain pine beetle within this type is currently increasing on the Forest. Whitebark and lodgepole pine are both affected by this current infestation. June Mountain, Rock Creek, Hilton Creek, and other locations scattered through the subalpine conifer type along the Sierran escarpment are experiencing dieoff; however, recruitment has been observed within the dying stands. The beetles tend to attack the larger more mature trees, resulting in a shift to younger smaller diameter stands. Aerial and ground surveys by the Forest Health Monitoring and Forest Health Protection programs of the Forest Service have identified unprecedented tree mortality levels in the southern Sierra Nevada, with some sites experience a loss of up to 95% of all trees >5 inches diameter at breast height (dbh) (Meyer et al 2012a). See Chapter 3 for additional information on insect-related mortality on the Forest.

The Inyo NF is beginning implementation of a restoration project in the subalpine conifer forest in and near the June Mountain Ski Area. Treatment objectives include improving forest health by making stands more resilient to insect and disease attack through thinning, burning, and removal of infested trees.

Of the forest types included within the subalpine conifer assessment type, lodgepole pine has been most affected by past and current activities, particularly timber management and fire suppression. Prior to the mid 1990s, clearcutting and overstory removal were common to release fir or younger lodgepole within the lodgepole pine areas considered suitable productive forest land (see Ch. 8 Timber discussion). Under the Forest’s Old Growth Strategy, implemented in the core area during the early 1990s, 10% of the timber management area was identified as old growth, and not treated during the planning cycle.

As described in Chapter 8 – Timber, the core area of timber management activity on the Inyo NF is the forested belt spreading east from the Mammoth Lakes-June Lake areas of Mono County through the Glass Mountain area. Lodgepole pine in this core area has historically been used to supplement the wood volume coming from the Jeffrey pine forests. Today, lodgepole pine removed from the Forest is coming from treatments within the Jeffrey pine forest (Johnson 2013). Much of the lodgepole pine forest on the Inyo NF has not been logged, with the possible exception of isolated small scale activities that may have occurred earlier in the 20th century in other parts of the Forest. Lodgepole pine is a highly valued species for local fuelwood cutters; as such, most lodgepole stands within wood gathering areas have a paucity of large woody debris. In addition, illegal snag cutting occurs in this type. The core area for timber management has higher road densities than any other area on the Inyo NF, due in part to timber management activities, and in part to subsequent OHV use.

Based on the NRV analysis, due to relatively long mean fire return intervals most Sierra Nevada subalpine forests have missed only one or two fire cycles, suggesting that the ecological effects of fire suppression in these forests are relatively minor or negligible compared to the fire-frequent mixed-conifer and yellow pine forests (Long et al 2013, Miller and Safford 2012, vanWagtendonk et al 2002, all cited in Meyer 2013a). Lodgepole pine, with more mixed fire regime and more abundant surface and canopy fuels has likely been more affected than other subalpine types. This, combined with the timber management history, as resulted in higher tree densities, smaller average tree diameters, and reduced forest heterogeneity in the lodgepole pine forests on the Inyo NF.

With regard to historic livestock grazing, late 19th century sheep grazing in particular has been reported to have impacted subalpine conifer forests in the Sierra, especially in relatively mesic forests (Meyer 2013a). Most subalpine conifer forests in the Eastern Sierra are generally at the lower end of the scale with regard to understory productivity, limiting their forage value. However, meadows within the subalpine conifer forests on the Inyo NF are another story, and are addressed in the Riparian Ecosystems section.

So far, non-native invasive plant species are a minor factor affecting the ecological integrity of subalpine conifer systems on the Forest; nevertheless, five non-native species have been reported from the subalpine conifer forest assessment type on the Forest, totaling approximately 600 acres. Cheatgrass, as in all of the assessment types, is the most common non-native species by far in the subalpine conifer forest type. It typically occurs in low densities, and is mostly restricted to disturbed areas.

The more accessible areas of the subalpine conifer type are popular areas for recreation. Many of the campgrounds and resorts on the Inyo NF are located in or adjacent to the subalpine conifer forest assessment type. The two alpine ski resorts on the Forest are located partially within the subalpine conifer forest type.

Lodgepole pine, whitebark pine, mountain hemlock, and other subalpine conifer forest types have been and are continuing to be affected by volcanism. Pockets of mortality due to concentrations of carbon dioxide in the soil currently exist on the Forest, such as the lodgepole pine mortality in the vicinity of Horseshoe Lake.

In very general terms, the impacts of the activities above include changes in vegetation structure and composition and soil productivity, thereby affecting many other components and processes in these ecosystems.

One or more elements of the subalpine conifer assessment type are target elements within established RNAs:
  • Whippoorwill Flat: limber pine
  • White Mountain: bristlecone pine
  • Last Chance Meadow: foxtail pine
  • Sentinel Meadow: lodgepole pine, limber pine
  • Harvey Monroe Hall: Sierran mixed subalpine forest

The subalpine conifer forest assessment type also occurs within McAfee Meadow RNA, though it is not designated as a target element there. RNAs are discussed in more detail in Chapter 15 – Designated Areas.

Among the subalpine conifer forest types, the Great Basin bristlecone pine is especially noteworthy. Known for being the oldest living trees on the planet, the bristlecone pines are afforded extra protection on the Inyo NF within the congressionally designated Ancient Bristlecone Pine Forest, a Special Interest Area managed to protect the bristlecone pines for public enjoyment and scientific study. The Great Basin bristlecone pine is especially valuable for climate-related research. Minor levels of insect and/or disease-related mortality can be seen within the bristlecone pine forest on the Inyo NF. So far, this appears to be limited in scope, suggesting it is within the NRV for these forests.

More information on the Ancient Bristlecone Pine Forest Special Interest Area can be found in Chapter 15.

A large majority (84%) of the subalpine conifer forest assessment type is currently within designated wilderness.

Trend
Climate envelope models consistently project that subalpine conifer forests in the Sierra Nevada bioregion are highly vulnerable to climate change and are at risk of substantial future loss (average 85%) by the end of the century. . The projected loss of subalpine forest in the southern Sierra Nevada is nearly twice that for the entire state of California (Southern Sierra Partnership 2010 cited in Meyer 2013a).

Whitebark pine has recently been listed as a Candidate species by the U.S. Fish and Wildlife Service, indicating concern for the long term viability of this keystone species. This is due primarily to the widespread mortality occurring across much of its range due to white pine blister rust (WPBR) and other causes, as well as projected trends. WPBR is a non-native pathogen causing substantial mortality of whitebark pine in other parts of its range. The Inyo NF, like the rest of the southern Sierra, has shown no signs of WPBR affecting whitebark pine (Meyer et al 2012). Mountain pine beetle, a native insect, is the agent currently affecting whitebark pine on the Inyo NF. Mortality currently occurring on the Inyo NF may continue to spread in the coming years.

4) Jeffrey Pine Assessment Type
Current Conditions
Jeffrey pine forest is found scattered along the escarpment of the Sierra, as well as on the Kern Plateau, but is most common in the Glass Mountains and Upper Owens River area, i.e. the core timber management area as described in Chapter 8 - Timber. The understory in this type varies from a sparse, duff-laden forest floor, to relatively low cover of perennial grasses and forbs, to sagebrush and bitterbrush scrub and/or montane chaparral. Understory cover is higher in forest openings. The Jeffrey pine forest assessment type includes “pure” Jeffrey pine forest, as well as Jeffrey pine in combination with pinyon or other pines, and fir in small amounts. Jeffrey pine forests with significant amounts of fir are included in the mixed conifer type.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of Jeffrey pine forests on the Inyo National Forest.

Table 8. Indicators for Jeffrey pine assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Heterogeneity
Variation in canopy cover, tree diameters, tree density
Variance among plots
FIA
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ration shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Structural complexity
Overstory density
Tree density by size class
FIA
Connectivity, fragmentation
Patch size
Acres – average and range
FIA
Special components
Snags & down woody debris
#/acre, tons/acre by size and decay class
FIA
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem composition – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres, 10 year intervals
Fire history?

Fire suppression and timber management activities have had significant effects on the Jeffrey pine ecosystem on the Forest. Similar to the lodgepole pine forests addressed in the subalpine conifer assessment type, timber management activities in the Jeffrey pine forest have been concentrated in the “core area” from the Mammoth/June area east to the Glass Mountains. Exceptions to this are the logging activity in the mid-20th century east of Crowley Lake, and possible small scale activities that may have occurred earlier in the 20th century in other parts of the Forest (Johnson 2013). Although the focus of past and present timber management activities, much of the acreage within the core area is excluded from timber activities due to wildlife habitat, steep slopes, recreation facilities, etc. As such, approximately 18% of the area classified as productive forest land on the Inyo NF is actually considered suitable for active timber management (see Ch. 8 - Timber discussion).

Within the suitable acres, overstory removal was the focus of past timber management activities in the Jeffrey pine forest. Overstory removals and clearcuts of old growth have not occurred since 1998 (Higley 2013). As mentioned in the subalpine conifer forest discussion, implementation of the Old Growth Strategy began in the 1990s. Current activities include commercial and pre-commercial thinning, with the goal of restoring forest health and building resiliency within the Jeffrey pine forest. Past management has contributed to creating high road densities in the core area, which have increased in more recent years with increasing OHV use in this area.

The 2013 Science Synthesis Report completed to support Forest Plan Revision in the Sierra Nevada Forests provides information on the pre-European settlement conditions of yellow pine forests on the west slopes of the Sierra Nevada mountains. Specifically, west side yellow pine forests were relatively open, patchy stands composed of primarily large, fire-resistant trees, with a high degree of spatial complexity that included patches of shrubs and relatively dense even-aged stands (Collins and Skinner 2013). The authors go on to point out that some eastside pine forests as found on the Inyo NF may have greater variability in fire frequency and fire effects, and that effective fire suppression generally occurred later than in low elevation forests of the west side of the Sierra Nevada. Unpublished data collected by Inyo NF personnel at Indiana Summit Research Natural Area (ISRNA) confirms this pattern of open forests dominated by large trees, with a high degree of heterogeneity across the landscape (Ch. 8 – Timber).

By 1950, trees and stumps at ISRNA and elsewhere in the Mammoth Lakes – June Lake core timber management area show almost no fire scarring, as the efforts to suppress all wildland fires became highly successful. In addition, timber management practices from the early 20th century through the early 1990s emphasized removal of most of the older, larger pine and fir trees for their commercial value, as described above.

The effects of this combination of timber harvest and fire suppression was similar to that reported in the Science Synthesis (vanWagdentonk and Fites-Kaufman 2006, Scholl and Taylor 2010, Collins et al 2011, all cited in Collins and Skinner 2013), i.e. a shift in forest structure towards increased tree densities, smaller average tree diameters, elevated surface fuel loads, and homogenization across the landscape. Smaller isolated patches of Jeffrey pine on the Inyo NF may have escaped these influences, at least to some degree.
Recent fires that burned partially within the Jeffrey pine assessment type include the Crater fire (2001, 5,570 acres, approximately 1/3 of this in Jeffrey pine), and the Dexter fire (2003, 2,515 acres).

Some minor localized impacts from insects and disease exist in the Jeffrey pine type on the Forest, consisting of pockets of pine beetle mortality as well as Anosus root diseaes. These outbreaks are treated somewhat aggressively when detected.

As pointed out in the discussion of lodgepole pine forests (subalpine conifer assessment type), the highest road densities on the Forest occur in the core area for timber management, which includes a majority of the Jeffrey pine assessment type.

The Jeffrey pine type is a very popular ecosystem for both summer and winter recreation. Camping, fishing, OHV use, and mountain biking are some of the summertime activities, switching to snowmobiling and cross country skiing in the winter months. Other land uses and/or natural processes that have affected the structure, composition, and/or function of the Jeffrey pine forest include mineral prospecting and development, various special uses, livestock grazing, and geothermal energy development, resulting in changes in vegetation composition and structure, as well as soil productivity.

Invasive annual grasses are patchy in this type, and are currently confined primarily to disturbed openings such as sheep bed grounds and timber landings, and open geothermally heated areas, where cheatgrass occurs in fairly high densities. There are currently 8 non-native plant species reported in the Jeffrey pine assessment type on the Forest, occupying over 3,000 acres in varying densities. Aside from cheatgrass, tansy mustard (Descurainia sophia) is the most common of the non-riparian non-native species.

Jeffrey pine is the target element of the Indiana Summit RNA. The RNA is within a large tract of Jeffrey pine forest stretching from the eastern flank of the Sierra Nevada across the divide between the Mono Basin and the Owens River drainage (Keeler-Wolf 1990). The RNA, contrary to the surrounding Jeffrey pine forest, has not been logged in the past; however, fire suppression has affected forest structure and composition to some degree (see discussion above). The Jeffrey pine assessment type also occurs within the Sentinel Meadow RNA. See Chapter 15 for more information about RNAs.

Only about 5% of the Jeffrey pine assessment type is within designated wilderness.

Trend
As with all ecosystems on the Forest, a warming climate could have a significant effect on the Jeffrey pine ecosystem. Invasive species, especially cheatgrass, will likely have an increasing impact on the ecological integrity of Jeffrey pine forests on the Inyo NF.

Fire management will continue to be an important issue into the future. The presence of communities within and adjacent to the Jeffrey pine forest requires some degree of fire suppression; however, complete and constant suppression without concurrent fuels treatment will likely lead to increasingly large and/or severe fires that are outside the NRV for this type, particularly given the projections for a warming climate.

The desire to further develop geothermal resources in this assessment type is likely to continue, and perhaps increase in the coming years. As stated in the sagebrush discussion, expansion of existing geothermal production is currently proposed in this type.

Increasing population may result in an increased demand for recreation on the Inyo NF, affecting the condition of the Jeffrey pine assessment type through increased OHV activity, and additional demands for camping, snowmobiling, and other recreation activities. However, Forest efforts to curtail illegal OHV activity and restore routes that are not part of the designated road and trail system should lead to an overall reduction in road density in this type.

5) Red Fir Assessment Type
Current Conditions
The majority of the red fir assessment type on the Forest is located on the Kern Plateau, in Reds Meadow, and in the Mammoth to June area. There are also scattered occurrences of this type along the Sierran escarpment, mostly near the lower elevations of the subalpine conifer forest. The red fir forests typically have relatively high canopy cover with a very sparse cover of perennial forbs and shrubs in the understory (Potter 1994), but some open areas also exist, with montane chaparral species such as chinquapin (Chrysolepis sempervirens) distributed in patches in the openings. Lodgepole, Jeffrey, and western white pine, as well as mountain hemlock can be found to varying degree in this type.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of red fir forests across the Inyo National Forest.

Table 9. Indicators for red fir assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Heterogeneity
Variation in canopy cover, tree diameters, tree density
Variance among plots
FIA
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ration shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Structural complexity
Overstory density
Tree density by size class
FIA
Connectivity, fragmentation
Patch size
Acres – average and range
FIA
Special components
Snags & down woody debris
#/acre, tons/acre by size and decay class
FIA
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem composition – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres, 10 year intervals
Fire history data

Logging in the red fir assessment type has been limited on the Inyo NF. There were some strip clearcuts of large trees (approximately 20 acre units) in the early 1980s in the vicinity of the Scenic Loop. These were replanted with red fir unsuccessfully more than once; lodgepole pine was then planted with some degree of success. There were also timber sales in the Sawmill and Dry Creek areas at that time that selectively removed red fir. Salvage of red fir occurred in the late 1980s following the Mammoth burn (Higley 2013). Aside from these sales, there may have been some logging around the eastern fringe of the red fir assessment type in the area northeast of Mammoth prior to the 1970s (Johnson 2013). Ecology plots report old stumps in this area. As in the Jeffrey pine forest, scattered small operations may have occurred earlier in the 20th century, but information is limited. The current Forest Plan calls for no timber harvest in red fir this planning cycle.

The 2013 Science Synthesis reports a mixed-severity fire regime for red fir forests (Parker 1984, Skinner 2003, Sugihara et al 2006; cited in North 2013), but notes that this is variable, with lower elevations on drier sites having lower historical fire return invervals with frequent pulses of regeneration compared to higher more mesic sites (Taylor 2004, Scholl and Taylor 2006; cited in North 2013). Relatively isolated stands, e.g. pockets surrounded by expanses of granite, may also have had longer return intervals. Studies reviewed in North suggest stands have missed one or more burn events, and consequently are likely to have increased fuel loading, higher stem densities, less light in the understory, and reduced shrub cover (Stephens 2001, Taylor 2000, Selter et al 1986, North et al 2002; cited in North 2013). The NRV analysis for red fir in the bioregion also reports a shift in tree size class distribution to smaller diameters, greater homogenization of forest structure at both stand and landscape scales, and a decrease in the density of large diameter red fir trees (Meyer 2013b). Red fir stands on the Inyo NF likely follow this pattern where there have not been recent fires or wind events.

Moderate to large fires in recent decades in the red fir assessment type include the Rainbow and McNally fires. The Rainbow fire of 1992 burned approximately 8,800 acres in the red fir assessment type, in the Reds Meadow area. At the south end of the Forest on the Kern Plateau, the McNally fire of 2002 burned approximately 150,000 acres, which included a significant portion of the red fir assessment type in this area. Lodgepole pine, a common component in the red fir type, will often become established as an early seral type following stand replacing events in red fir on the Forest, providing shading for eventual regeneration of red fir (Higley 2013).

It would be impossible to talk about the current conditions of the red fir assessment type on the Forest without a brief synopsis of “the blowdown” – the significant wind event that occurred across the Inyo NF and neighboring National Parks and Forests in November of 2011. While trees were toppled across the entire length of the Inyo NF, the most severe effects were focused in the Middle Fork San Joaquin River drainage, in the red fir assessment type. Approximately 220 acres in the Reds Meadow area on Inyo NF lands outside of wilderness were reported as having severe tree damage, primarily affecting mature red fir and lodgepole pine. Substantial additional affected acres remain unsurveyed in Devil’s Postpile National Monument and within wilderness on Inyo NF in the Reds Meadow Valley. Approximately 37% of the down trees in the surveyed area had a diameter greater than 20 inches. Preliminary estimates indicated an average of 54 wind-fallen trees per acre in patches with severe wind damage (USDA Forest Service 2012b). The Forest is in the process of treating a portion of this area, to reduce fuel loads and restore recreation opportunities and facilities.

Non-native invasive plant species in the red fir type are mostly confined to high use areas such as campgrounds and along roads. The red fir assessment type is mostly shady, and therefore not particularly susceptible to invasion except via disturbance. Approximately 685 acres are currently reported to have some degree of invasion by non-native plant species. Though seven species are reported, cheatgrass is the only one with significant acreage.

Recreation is also popular within the red fir forest, and includes campgrounds, OHV activity, dispersed camping, resorts, etc. Both of the downhill ski areas on the Forest are located at least partly within the red fir assessment type.

Red fir is not a target element in any of the RNAs on the Forest, nor does it occur within any of the existing RNAs on the Forest.

A large proportion (80%) of the red fir assessment type is within designated wilderness.

Trend
Anticipated trends in the red fir forest assessment type are similar to those for Jeffrey and lodgepole pine, i.e. a continued trend towards higher fuel loading, and changes in forest structure and composition associated with fire suppression coupled with a changing climate.

6) Mixed Conifer Assessment Type
Current Conditions
Absent from the White, Inyo, and Glass Mountains (though small patches of mixed conifer forest may occur), the mixed conifer assessment type is found along the escarpment of the Sierra, typically at the lower edge of the subalpine conifer forest and/or red fir assessment types, and the upper edge of the pinyon-juniper assessment type. It occupies roughly the same elevation band as the mountain mahogany assessment type along the Sierra escarpment, but is restricted to the cooler, moister environments, often in deep drainages or on steep slopes. On the Inyo NF, it is most prevalent on the Kern Plateau. The mixed conifer assessment type includes various combinations of white fir, red fir, and/or one or more pine species, typically with a very sparse understory.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of mixed conifer forests across the Inyo National Forest.

Table 10. Indicators for mixed conifer assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Heterogeneity
Variation in canopy cover, tree diameters, tree density
Variance among plots
FIA
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ration shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Structural complexity
Overstory density
Tree density by size class
FIA
Connectivity, fragmentation
Patch size
Acres – average and range
FIA
Special components
Snags & down woody debris
#/acre, tons/acre by size and decay class
FIA
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem composition – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres, 10 year intervals
Fire history

Stands of mixed conifer forest occur not only within the mixed conifer assessment type, but within the red fir, Jeffrey pine, and subalpine conifer assessment types as well. As stated in the Introduction, the scope of this analysis does not allow for fine scale mapping that identifies vegetation at the stand scale. Mixed conifer stands within the core area for timber were heavily harvested with overstory removals in the 1980s in the Sawmill, Dry Creek, and Deadman areas (Higley 2013). Similar activity occurred east of Highway 395, though to a lesser degree due to its occurrence on steeper slopes in that area. The majority of the mixed conifer assessment type (which does not necessarily include all mixed conifer stands) in the core timber management area was included in the Owens River Headwaters Wilderness, designated in 2009. Historical logging may have occurred elsewhere in the mixed conifer assessment type on the Forest, particularly to remove large pines within these stands.

Fire suppression has likely been the main activity that has had the most significant impact on the structure and composition of the mixed conifer ecosystems on the Forest. The Science Synthesis (Collins and Skinner 2013) and the NRV analysis for yellow pine and mixed conifer forests (Safford 2013) characterizes mixed conifer as having a fire regime of frequent low to moderate severity events, which served to maintain forests with large trees, open stands, and a highly heterogeneous forest landscape, with montane shrubs (Arctostaphylos, Ceanothus) in openings. According to both of these sources, current conditions in the Sierra Nevada ecoregion include higher tree densities, smaller average tree size, and increased fuel loading. Conditions in the mixed conifer forests on the Inyo NF are likely similar to those described for the ecoregion as a whole.

The Summit fire on the Kern Plateau (2003, 4,761 acres) burned primarily within the mixed conifer assessment type.

Cheatgrass is the only non-riparian invasive plant species recorded in the mixed conifer assessment type. There are approximately 300 acres currently occupied by non-native plant species in this type. The typically high canopy cover and duff layer provide some resistance to invasion, except where disturbed.

With the exception of Monache Meadow on the Kern Plateau, approximately ¾ of the mixed conifer assessment type is within wilderness, though as explained previously, there are stands of mixed conifer forest on the Inyo NF that are outside of the mixed conifer assessment type as it is currently mapped for the purpose of this assessment. Other than fire suppression, management activities in the past few decades in the mixed conifer forest assessment type in wilderness have been limited primarily to non-motorized recreation. Outside of wilderness, recreation residences, resorts, and campgrounds are sometimes located within this assessment type, due to its location in mid to high elevation canyon bottoms.

Mixed conifer is not a target element in any of the RNAs on the Forest, nor does it occur within any of the RNAs on the Forest.

Trend
The factors affecting trend and the anticipated effects on the mixed conifer assessment type are similar to those discussed for Jeffrey pine and red fir assessment types, and the lodgepole pine component of the subalpine conifer forest assessment type.

7) Mountain Mahogany Assessment Type
Current Conditions
The mountain mahogany assessment type is found throughout the Forest, in the Sierra, Inyo, White, and Glass Mountains. It often occurs on steep cliffs, rocky slopes and outcrops, or on broad ridge tops near the upper limit of big sagebrush, and below subalpine conifer forests. Mountain mahogany has massive, deep roots that enable it to occupy habitats where other shrub species are unable to obtain water or hold the surface with stability (USDA Forest Service 2006). The mountain mahogany assessment type includes not only mountain mahogany (Cercocarpus ledifolius), but littleleaf mountain mahogany (Cercocarpus intricatus) found on carbonate substrates, in addition to mountain mahogany in combination with sagebrush, pinyon, and other trees and shrubs. This assessment type also includes some montane chaparral (Appendix A).

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of mountain mahogany across the Forest.

Table 11. Indicators for mountain mahogany assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Physiognomy
Proportion tree vs. shrub vs. herb
Ratio tree: shrub
Ration shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem function - erosion
Proportion bare soil
Percent bare soil
TEUI
Ecosystem composition – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRSI
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres, 10 year intervals
Fire history

The typically sparse fuels make fire uncommon in this type on the Inyo NF. Riegel et al (2006) report that mountain mahogany can survive for long periods, as these areas are not frequently disturbed by fire due to low fuel levels. In one location in northeastern California, mountain mahogany plants were found to be more than 400 years old. If a fire does occur, this type is often replaced by more diverse montane chaparral, with mountain mahogany perhaps not becoming dominant for as much as 100 years or more (USDA 2006). Riegel et al classified mountain mahogany as being a weak sprouter, and highly susceptible to fire, with re-establishment largely dependent on seedling establishment.

Small portions of the Fuller (2002) and Tom fires (1998) burned within the mountain mahogany assessment type.

Due to the steep rocky nature of the mountain mahogany ecosystems, human use in these areas has been and continues to be relatively limited. Mineral development, roads, and dispersed recreation are the primary factors affecting the condition of this ecosystem on the Forest. Livestock grazing has been minimal due to the difficult terrain and sparse forage.

With regard to non-native invasive species, cheatgrass is again the main stressor in the mountain mahogany assessment type, as it is in all others. Seven non-native plant species occupy over 1,600 acres in this type; almost all of this is cheatgrass. Tansy mustard is the second most common non-native plant species in this ecosystem.

Mountain mahogany is not a target element in any of the RNAs on the Forest, nor is this assessment type within any of the RNAs. Based on the finer scale mapping of the ecological surveys conducted specifically for the RNA program (Keeler-Wolf 1990), there are small areas of mountain mahogany within the Whippoorwill Flat, White Mountain and Sentinel Meadow RNAs.

Fifty-eight percent (47,131 acres) of the mountain mahogany assessment type is within designated wilderness.

An interesting side note: in late summer, mountain mahogany shrubs are covered with fuzzy-tailed fruits, creating a dazzling display when backlit by the sun, enhancing the recreation experience for many, particularly in the heavily used canyons of the Eastern Sierra, e.g. Rock Creek, Bishop Creek, and others.

Trend
Cheatgrass is likely to spread and increase in density following fires in the mountain mahogany assessment type, as in many of the other types discussed above.

As with all assessment types, changes in climate could cause changes in the distribution and abundance of this ecosystem, as well as changes in the structure, composition, and processes affecting the ecosystem.

8) Xeric Shrub and Blackbrush Assessment Type
Current Conditions
At the opposite end of the elevation scale from the alpine areas, are the xeric shrub and blackbrush types. This assessment type occupies the very lowest elevations of the Forest, in the foothills of the Sierra, Whites, and Inyos, bordering the large valleys adjacent to the Forest (e.g., Owens, Chalfant, Hammil, Fish Lake, and Saline Valleys). This assessment type is also abundant on neighboring BLM and LADWP lands. The xeric shrub type includes several vegetation communities, including many different combinations of a diverse array of desert shrubs, adapted to low moisture/high temperature environments.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of xeric shrub and blackbrush ecosystems across the Inyo National Forest.

Table 12. Indicators for xeric shrub and blackbrush assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Physiognomy
Proportion shrub vs. herb
Ratio shrub: herb
TEUI
Successional stage
Proportion early/mid/late seral
Percent
TEUI
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem function - erosion
Proportion bare soil
Percent
TEUI
Ecosystem function – soil crusts
Cover of soil crusts
Percent cover
TEUI
Ecosystem function – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI
Ecosystem function - fire
Proportion in different FRCC classes
Percent

Ecosystem function – fire
Average fire size
Acres
Fire history
Stressors – grazing
Amendment 6 condition classes
Condition class (Excellent, Good, Fair, Poor)
Forest range monitoring

Past and current management activities and/or natural processes that have affected the current condition of xeric shrub and blackbrush ecosystems on the Forest include livestock grazing, fire suppression, wildland fire, mining, water spreading, various special uses such as apiaries and weather stations, and recreation uses, particularly OHV activity. This assessment type is less popular for overnight use such as campgrounds, but is close to the population centers in the Owens Valley, resulting in its popularity for evening and weekend daytime activities, such as walking and OHV play. Bouldering has become increasingly popular over the past couple of decades, bringing more recreationists to the area during the “shoulder seasons”. Beyond the Forest boundaries, potential solar development is an emerging issue in these ecosystems.

The fire regime in this assessment type is described by Brooks and Minnich (2006) as relatively moderate to large-sized, patchy to complete, moderate severity, surface to crown fires, with a long fire return interval. The invasion of non-native annual grasses is shortening this return interval. The Oak fire in 2007 (27,063 acres) burned largely within the xeric shrub and blackbrush assessment type.

The Oak fire was followed one year later by an intense rain event, which generated debris and hyper-concentrated flows, subsequently burying approximately 3 square kilometers of the burned area under sediment scoured from channels. Investigations suggest recurrence intervals for similar events are on the order of several hundreds of years (Wagner et. al. 2012). This area is beginning to show signs of recovery; however, non-native species are abundant, and the stream channel is significantly downcut, limiting the potential for successful regeneration of native vegetation. The Forest is pursuing options to implement active restoration treatments.

Six vegetation condition transects were completed in the xeric shrub assessment type for the purpose of range monitoring. All six transects rated excellent.

Non-native invasive annual grasses are a significant issue in the xeric shrub ecosystems, especially on lands immediately adjacent to population centers. In addition to cheatgrass, red brome (Bromus madritensis ssp. rubens) is common in this type as well, and Mediterranean grass (Schismus arabicus) is also present. Red brome and Mediterranean grass are more common invasives in the Mojave bioregion, while cheatgrass is more common in the Great Basin. There are a total of 14 terrestrial non-native plant species reported in this assessment type, occupying over 6,400 acres on the Forest. In addition to these 14 species, saltcedar, normally confined to riparian areas, has become established in some areas within this assessment type where water spreading activities have occurred.

In addition to the ecological concerns, the loss of diversity in the xeric shrub system due to annual grass invasion can significantly affect the recreation experience during the springtime. The wildflower displays that bring thousands of people to the deserts in the spring consist of a multitude of annual as well as perennial wildflower species. The annual wildflowers in particular can decline in the face of competition with the non-native annual grasses.

Neither xeric shrub nor blackbrush are target elements in any of the RNAs on the Forest, nor are there portions of this type within any RNA boundaries on the Forest.

Approximately one fifth (40,269 acres) of the xeric shrub and blackbrush assessment type on the Inyo NF is within designated wilderness.

Trend
As in the pinyon-juniper and sagebrush ecosystems, invasive annual grasses have the potential to change the fire regime in this type, and possibly lead to a type conversion from a diverse shrubland to a monoculture of non-native annual grass. These annual grasses are likely to continue to increase in the coming years, with a warming climate being a contributing factor.

Interest in wind and solar energy development in xeric shrub ecosystems is increasing, and is likely to continue, potentially resulting in a demand for energy production from this ecosystem on the Inyo NF. Proposals already exist for solar development on LADWP lands nearby. See Chapter 10 for more information on renewable energy potential on the Inyo NF and adjacent lands.

Potential increases in OHV activity associated in part with an increasing human population may result in introducing new and spreading existing invasive species in these xeric shrub areas.

9) Alpine Assessment Type
Current Conditions
The iconic alpine areas of the Eastern Sierra fall within this assessment type, located at the highest elevations of the Sierra Nevada and White Mountains. Almost all (95%) of the alpine type is within designated wilderness, where human impacts are relatively minor, with the exception of larger scale influences such as climate and air pollution. These larger scale processes, which potentially affect not only the alpine, but all other ecosystems as well, are addressed in Chapter 3.

The following table of indicators displays factors relevant to the current condition of the function, structure, and composition of alpine ecosystems across the Inyo National Forest.

Table 13. Indicators for alpine assessment type.
Attribute being measured
Indicator
Measure or Unit
Source
Heterogeneity
Proportion in associations, complexes, inclusions
Percent
TEUI
Fragmentation
Road density
Miles/acre
Forest road data
Fine scale biodiversity
Species richness
  1. species
TEUI
Ecosystem composition – invasives
Number of invasive species
Count
NRIS
Ecosystem function – invasives
Extent of invasives
Acres occupied
NRIS
Ecosystem function - invasives
Cover of invasive annual grasses
Percent cover of cheatgrass and red brome where they occur, i.e. “0” plots not counted
TEUI

As stated above, management activities are relatively limited in the alpine zone. Dispersed recreation, such as hiking, backpacking, rock climbing, and pack stock trips, are popular activities here. These activities affect a relatively small proportion of the land, and, with the exception of rock climbing, are concentrated in and around lakes, meadows, and streams.

The sparse fuels and weather conditions in the alpine assessment type are not conducive to fire ignition or spread. Fires are so infrequent that they probably did not play a role in the evolutionary development of the plants that occur in the alpine zone (van Wagtendonk and Fites-Kaufman 2006).

With regard to non-native invasive species, the alpine is the least invaded of any of the assessment types, with only 7 acres reported at this time. Cheatgrass is currently the only terrestrial non-native plant species in this assessment type. Cheatgrass is the most likely terrestrial invasive plant species to persist and potentially expand in alpine environments, since it is already persisting above 2,700 meters, (9,000 ft) elevation along the Shepherd Pass trail.

A majority of the alpine assessment type on the Forest crosses the Forest boundary uninterrupted into National Parks or other National Forest Wilderness, where the uses and goals are similar in nature.

Alpine meadows are a target element in the Harvey Monroe Hall RNA, and alpine fell fields are a target element in the McAfee Meadow RNA. These are the only RNAs that contain alpine communities. See Chapter 15 for more information about RNAs.

Trend
Additional acres of the alpine assessment type have been designated as Wilderness in recent years, providing additional protection to this assessment type on the Forest with regard to those uses and management practices prohibited in Wilderness, such as motorized vehicles and equipment. Due to the high elevation, the risk of significant increases in invasive plant species in the alpine assessment type are less than in other types; however, changes in climate could reduce that resistance.

10) Special Types
Current Conditions
Several unique terrestrial plant communities occur on the Inyo NF that do not occur in large enough areas to be included in the TEUI mapping effort. These communities represent an important component of the biodiversity on the Forest. Unique ecosystems on the Inyo NF include: aspen (12,460 acres from TEUI special types; 24,245 acres from aspen GIS layer used in this assessment), dry forb (13,960 acres), and alkali flats (9,370 acres). These communities are described in more detail below. Riparian communities are addressed in the Riparian Ecosystems section.

Aspen is the most common ecosystem included in the special type category. Aspen supports a high level of biodiversity, with many wildlife species utilizing aspen stands during some stage of their life cycle. In addition, aspen are popular with recreationists for many uses, including hunting, camping, fishing, fall color viewing, or simply providing a shady oasis effect in an otherwise arid landscape.

The Inyo NF conducted aspen inventories and condition assessments from 2008 to 2010. The information used here comes from the aspen GIS layer created for that effort. The aspen layer was derived from a combination of the TEUI PNV map and Regional E-veg data. Areas identified with aspen as a primary type or with aspen in the understory in either of these datasets were included in the aspen layer. Since the aspen layer combines two vegetation layers and includes some areas currently dominated by conifers, it delineates additional aspen (24,245 acres) over and above that delineated in the TEUI layer alone for aspen dominated areas (12,460 acres). Field surveys focused on those areas that appeared to potentially be at risk due to conifer encroachment or other factors.

Approximately 10% of the stands identified in the aspen layer have been surveyed (139 stands). Individual aspen stands were classified as being at low, moderate, high, or highest risk of losing the stand. Risk categories were based on the Regional protocol.

Results of the Inyo NF aspen surveys are shown in the following table.

Table 14. Risk of loss for surveyed aspen stands
Risk Category
Acres
Percent
Highest
64
3
High
269
11
Moderate
645
27
Low
1137
48
None
242
10

One percent of surveyed stands were classified “n/a”, likely due to a lack of aspen (i.e., stand misclassified in GIS aspen layer).

Conifer encroachment, poor regeneration due to competition from overstory trees, and disease are the three primary issues currently affecting the ecological integrity of aspen stands on the Forest. Of the 24 stands rated highest and high risk of loss, 10 had poor or suppressed regeneration, and 16 had conifer species overtopping aspen. Disease was recorded as an issue in 9 of the 24 stands. Of the 62 stands rated with a moderate risk of stand loss, 15 had poor regeneration or suppressed regeneration, and 34 had conifer species overtopping aspen. Nineteen stands had disease affecting over 20% of stems in the stand. Drought may be a factor in the frequency of disease in aspen stands on the Forest.

Only two of the 139 stands surveyed identified intense browsing pressure, defined as current terminal leader growth completely removed on >20% of stems. One of these was in a packstock pasture, and one was “unknown”. Fifty-six stands had light to moderate browsing pressure, with deer as the primary browser identified.

The NRV analysis for subalpine conifers states the historic frequency and extent of lodgepole pine encroachment into aspen stands of the Sierra Nevada is poorly understood (Meyer 2013a). The quaking aspen riparian plant associations in the Sierra Nevada may follow a successional sequence that leads to the dominance by lodgepole pine or red fir (Potter 1998, cited in Meyer 2013a). This sequence is especially apparent in aspen stands experiencing longterm fire exclusion and elevated livestock grazing pressure, which can potentially impact aspen regeneration. Estes (2013) finds that fire has been the most consistent influence on the extent and health of aspen. She also notes that aspen east of the Sierra crest can be found outside of riparian areas, unlike on the west side of the Sierra.

Sudden aspen decline, or SAD, is affecting many aspen stands across the West. It is characterized by sudden extensive stand mortality, little to no regeneration, and root death (Morelli et al 200X). To date, there is no clear evidence of SAD on the Inyo NF.

Cheatgrass is the most common invasive plant species found in aspen stands on the Forest. Other invasives that are of highest concern and known to occur within aspen stands include perennial pepperweed, spotted knapweed, lenspod whitetop, and bull thistle. There are over 500 acres of non-native plant species recorded within aspen stands on the Forest.

Aspen is the only special type that is specifically noted within RNAs on the Forest. While it is not a target element in any of the RNAs, it does occur in the White Mountain RNA. Mono pumice flats, part of the dry forb type discussed below, may occur within the Indiana Summit and/or Sentinel Meadow RNAs, though they are not specifically mapped there.

Dry forb is another special type found on the Forest. The dry forb type consists primarily of the pumice flats in the Mammoth to Mono Lake area, and the sandy colluvial aprons on the meadow margins on the Kern Plateau. Cover is typically very sparse in these areas, and generally dominated by herbaceous species. The pumice flats and the colluvial aprons both provide habitat for rare endemic plant species found only in these habitats in these locations, e.g. Mono milkvetch (Astragalus monoensis) and Mono Lake lupine (Lupinus duranii) are both endemic to the pumice flats of Mono County, found only on the Inyo National Forest and neighboring lands, and the Ramshaw Meadows abronia (Abronia alpina) found only on the sandy colluvial aprons in two meadows on the Kern Plateau. The California Natural Diversity Database tracks Mono pumice flats as a rare community.

Vegetation cover in the dry forb type is generally too low to carry fire, so these areas have not likely been significantly affected by fire suppression over the years, except perhaps on the very edges where adjacent forests or shrublands occur. Livestock use, particularly trampling by cattle or sheep, has been common in this type. The soils, being very porous, are somewhat resistant to compaction, but plants are susceptible to uprooting due to the unconsolidated structure of the soils. The dry forb type is characterized by a very high diurnal variation in temperature, with high surface temperatures in the daytime contrasting with nighttime lows. No significant insect and disease issues have been noted in these communities.

The inhospitable environment of the dry forb type seems to discourage even invasive plants from establishing or persisting. No non-native species are reported from this type on the Kern Plateau, and the only report from the pumice flats is an occurrence of Russian thistle along the highway where it passes through this type. Currently, vehicle use off of designated routes has the most impact on this type. Due to the open nature of the terrain, and the loose soils, plants are easily uprooted by even a single vehicle pass. The Forest regularly rakes out vehicle tracks, and has begun the process of rehabilitating numerous unauthorized routes from these sensitive areas.

Alkali flats are found primarily in the Mono Basin, Long Valley, and Adobe Valley areas of the Forest. They typically have relatively fine, moist soils, with a high pH. Cover is sparse, and generally consists of salt-loving herbaceous species such as saltgrass (Distichlis spicata) and triglochin (Triglochin spp.) and sometimes rabbitbrush (Ericameria nauseosa, E. albida). In grazed areas, compaction of the moist heavy soils can be an issue, potentially affecting productivity of these ecosystems and/or leading to increased shrub cover. Fire suppression in adjacent types may have resulted in less frequent fire moving through the alkali flats, also contributing to an increase in shrub cover in these areas. Like the dry forb community, the alkali flats are susceptible to unauthorized off-road vehicle use due to the open gentle terrain. With their moist soils, the alkali flats are currently impacted by numerous invasive plant species, including saltcedar (Tamarix ramosissima), bouncing bet (Saponaria officinalis), and lenspod whitetop (Cardaria spp.). Livestock and recreational vehicles may serve as vectors for introducing weed species into these habitats, along with equipment used for various projects, e.g. minerals, range improvements, etc.

Trend
Aspen stands on the Forest may see an increase in conifer encroachment with continued fire suppression and limited resources for restoration treatments. As noted in the current conditions, some stands are already showing signs of decline. Changes in climate could have significant impacts on aspen stands on the Forest. Warming, combined with changes in available moisture for plants, could result in a reduction, alteration, or loss of this valuable ecosystem. As noted for most of the ecosystems discussed in this assessment, invasive species may increase in the coming years, exploiting the weakened state of native plants struggling to keep pace with habitat changes.

It is unclear how changes in climate could affect the dry forb type. Species that currently exist with minimal competition within this narrow range of conditions may not be able to persist as those conditions shift, potentially enabling other species to occupy these areas and outcompete the existing species. Given their dependence on subsurface moisture, the alkali flats may be especially vulnerable to changes in climate that affect water availability. The use of off highway vehicles for recreation has increased several-fold over the past decade. An increasing human population could result in further increases in this use, potentially impacting the open dry forb and alkali flat communities; however, Forest efforts to reduce illegal travel and rehabilitate existing roads should improve road density overall in these open areas.

References

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Meyer, Marc D. 2013a. Natural range of variability assessment for subalpine conifer forest. In draft. USDA Forest Service, Pacific Southwest Region, Vallejo, CA.
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Meyer, Marc D., B. Bulaon, M. MacKenzie, and H.D. Safford. 2012. Whitebark pine (Pinus albicaulis) mortality monitoring in the Inyo National Forest. USDA Forest Service Pacific Southwest Region and USDA Forest Service Forest Health Protection Whitebark Pine Restoration Program. 26 pp.
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North, Malcolm, B. Oakley, J. Chen, H. Erickson, A. Gray, A. Izzo, D. Johnson, S. Ma, J. Marra, M. Meyer, K. Purcell, T. Rambo, B. Roath, D. Rizzo, T. Schowalter. 2002. Vegetation and ecological characteristics of mixed conifer and red-fir forests at the Teakettle Experimental Forest. USDA Forest Service Gen. Tech. Rep. PSW-GTR-186.
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Potter, Donald A. 1998. Forested communities of the upper montane in the central and southern Sierra Nevada. Gen. Tech. Rep. PSW-GTR-169. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 319 pp.
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Aquatic Ecosystems

Introduction

The extensive landscape that makes up the Inyo National Forest (Inyo NF or Forest) provides for a diversity of aquatic ecosystems with unique characteristics. Aquatic ecosystems on the eastern side of the Sierra Nevada Mountains are discreet entities, usually separated by long distances of dry ecosystems, even riparian areas adjacent to streams and rivers are usually narrow stringers of lush vegetation. Although natural aquatic features dominate the Forest, man’s activities have also had an influence on the types of aquatic ecosystems found throughout the Forest.

Process and Methods

Scale of Assessment
The scale of this assessment extends to all water features within the boundaries of the Inyo NF. Where ecosystems, including ecosystem processes, cross Forest boundaries onto adjacent lands, the condition and trend of the ecosystem on those lands will be considered as it relates to the condition and trend of that ecosystem on Forest lands, and vice versa.

Information Sources
Information sources include the 2004 Sierra Nevada Forest Plan Amendment, the 1997 Sierra Nevada Ecosystem Project, local knowledge of the area, California State Department of Fish and Wildlife for species occurrence. Gaps include current population data for known species, as well as population locations and current condition of habitat in many of the land designations, such as the CARs, Wilderness, and Wild and Scenic Rivers.

Indicators
Indicators for aquatic ecosystem conditions include both abiotic and biotic components of ecosystems associated with water. The abiotic indicators include water quality (including temperature), water quantity and seasonal flow patterns. There are many different living organisms that could be used, but to focus the examination, macro-invertebrates, amphibians and presence of exotic invasive species will be used as biotic indicators. Not all indicators are applicable to all aquatic ecosystems.

Conditions and Trends of the Major Aquatic Ecosystem Types

In general, the Forest is characterized as a dry ecotone with few water sources, with limited aquatic habitat connectivity that has created areas of isolated populations and evolutionally divergent populations of similar species (e.g., all springsnail populations and salamander populations are genetically unique from one another). The eastern side of the Sierra Nevada ecosystem lies in the rain shadow of these great mountains, creating a dry and precipitation-dependent and driven system. As described in the Bioregional Assessment Chapter 1 topic paper for aquatic systems, the annual amounts of precipitation and streamflow are dependent on the total volume of water falling as precipitation as well as the timing of hydrologic processes such as snowmelt and streamflow. Depending on annual precipitation, water flows in some perennial streams can vary one year from high, sustained summer flows to being completely dry in the following year. The nature of these systems may address why fish were not native to the high elevations of the eastern Sierra Nevada Mountains. Instead, native species adapted to highly variable water levels throughout the landscape. Currently, artificial barriers within stream systems have become crucial in the preservation of rare and endemic species in order to protect native species from invading non-native species.

Aquatic ecosystems are characterized as lentic and lotic. Lentic ecosystems include ponds, tarns, lakes, springs and man-made lakes, or reservoirs. Lotic ecosystems include flowing water bodies, such as rivers, creeks, and streams.

Lentic Ecosystems
Lentic systems are those water features with static water, as opposed to flowing water systems. These include ponds, tarns, lakes, springs and man-made lakes, or reservoirs. Below are short descriptions of these water features on the Inyo National Forest and the special features they provide to species that depend on them.

Lakes
Current Conditions: Lakes on the eastern side of the Sierra Nevada Mountains can range in size from one acre to hundreds of acres. No lakes occur in the White Mountains, Inyo Mountains or Glass Mountains. Approximately 479 lakes occur on the Inyo National Forest, totaling about 46,000 acres. Larger lakes exhibit the characteristics of large water bodies, which include seasonal turn-over and “zones” within the lake that exhibit different characteristics, such as shoreline ecosystems and deep-water zones. These lakes typically freeze in the late winter with a thick layer of ice that insulates the water at the lower levels of the lake. The ice layer usually thaws by late spring or early summer, allowing for open water to remain through the summer months.

Historically the lakes of the high Sierra Nevada Mountains were fishless and supported native fauna such as amphibians, aquatic insects, abundant zooplankton and phytoplankton. The mountain yellow-legged frog was an abundant resident of these lakes, with a life cycle that accommodated the seasons of ice in the high country (Knapp 2007). These frogs are almost wholly aquatic and require water for their entire life. The aquatic larvae, or tadpoles, require several years at the tadpole stage before they metamorphose into young adults, and require water in the lake at all times during their larval stage. During the winter the frogs and tadpoles reside under the ice. The introduction of trout into these lakes changed the ecological relationship of the native fauna by largely eliminating frogs from these habitats (Knapp 2007; introduced trout prey upon tadpoles and juvenile frogs). Currently, many of the high elevation lakes support introduced trout species of brook, brown, rainbow and golden trout.

Lakes have few impacts from Forest authorized projects. The main impacts to these ecosystems include activities from Forest recreationists, including roads in areas outside of Wilderness. Impacts include lakeshore trampling of vegetation and soil, causing compaction that increases sedimentation and reduces infiltration of water to the soil, increasing run-off to the lakes. Human waste and trash may make their way into the water bodies. Fishing is described below.

The introduction of trout into lakes throughout the Sierra Nevada mountain range has had the effect of eliminating the mountain yellow-legged frog from over 95% of their historic range. Not only does the presence of fish reduce or eliminate frogs from their natal lake, but the presence of fish inhibits the dispersal of frogs from areas that they occupy into new areas. This limiting factor reduces the potential for gene-flow across populations and limits the ability of frogs to colonize new areas. The California Department of Fish and Wildlife has produced several High Mountain Lake Biodiversity Plans which describe the current distribution of the mountain yellow-legged frog and describes management to bring this species to almost 10% of its historic habitat. These plans identify the removal of fish from several lakes, usually those that are not popular fishing destinations, and also identify actions to improve fisheries in adjacent watersheds to compensate for the loss of a productive fishery.

The introduction of trout into these lakes has also altered the life-cycle and reduced the population numbers of macro-invertebrates and zooplankton within the lake. This reduction and/or elimination also affects the intensity of insect hatches, which has been shown to affect bird migration patterns. Birds such as the rosy-finch have depended on insect hatches from lakes in the Sierra Nevada Mountains during the time when they need to feed their young, thereby influencing the success of fledging their young. (Epanchin et al. 2010).

High mountain lakes provide the primary resource for fishing for Forest recreationists to enjoy. (See Chapter 8 for description of angling opportunities on the Forest.) The high quality water provides an excellent medium for growing and producing fish, especially trout, which thrive in cold, clear and clean waters. Fisheries resources are the responsibility of the California Department of Fish and Wildlife, the agency that determines where to stock fish, how much to stock, and how to manage the fisheries resources. They base these management decisions on public input from Creel samples, recreation surveys and incorporate budget and funding sources. The Forest supports these activities as a cooperative partner.

Trends: Fishing opportunities and recreation uses are expected to continue and impacts from those activities will continue to occur. The California Department of Wildlife is expected to continue the fish stocking program in many of the lakes, which will continue to affect the ecological trophic level with the continued depression of mountain yellow-legged frog populations. Restoration efforts to increase mountain yellow-legged frog habitat to 10% of its former range will continue to be implemented by the California Department of Fish and Wildlife. However, currently mountain yellow-legged frog occupied lakes are at a high risk of succumbing to the fungal pathogen Batrachochytrium dendrobatidis or Bd, and populations of frogs, regardless of the quality of habitat being provided, is expected to continue to decline.

Predictive models for effects of climate change are discussed in Chapter 3 – Drivers and Stressors. Observed changes as they relate to mountain lakes include shifts in the timing of snow-melt and length of time that the winter ice cover occurs on lakes. Water quantity in lakes may not change over the next 20 years, but timing and volume of flow from the outlet may be altered and/or reduced.

Reservoirs
Current Conditions: Scattered throughout the lower elevations of the eastern Sierra Nevada foothills are 26 lakes and meadows which have been enhanced by dams to increase the water holding capacity. Others have been dammed to store water for creating electricity, such as the Southern California Edison hydroelectric projects in the Bishop Creek drainage. Other man-made lakes, such as Convict and Rock Creek Lake, were created for holding water until summer time when water was needed for irrigation in the valley (see Chapter 8, Water Uses). These reservoirs and enhanced lakes provide habitat for introduced species of trout, and sometimes perch and provide a variety of water based recreational opportunities.

Reservoirs have created a new type of habitat on the landscape, creating larger water bodies than what existed prior to damming. The flooding of lakeshore meadow-type habitat has eliminated valuable habitat that was utilized by mountain yellow-legged frogs. Currently, reservoirs such as Sabrina, South, Rock Creek, Gem and Silver lakes are devoid of lakeside vegetation and are instead encircled by a vegetation-lacking “bath-tub ring” as water levels fluctuate. The presence of reservoirs and their use as highly desired fishing locations also provides a vehicle for the introduction of several invasive species, such as the New Zealand mud snail, zebra and quagga mussels, and California salamanders, which was brought into the area as bait. The Lahontan tui-chub is another non-native species introduced to the Forest. It has reproduced with the native Owens tui chub, threatening the existence of this fish as a unique species.

Trends: Reservoirs will continue to exist under current management and jurisdiction to fulfill their water storage and hydroelectric needs. No change in management is expected to occur within the next 20 years for these aquatic ecosystem types. As for aquatic invasive species, the threat of colonization by non-native invasive species increases each year as exposure from visitors continues. Visitors to the area may bring infected fishing gear, boats and other equipment into the reservoirs.

Finally, because most reservoirs are shallower than natural lakes, they are more susceptible to increased temperatures from solar exposure, nutrient input, which predisposes them to increased risk of invasive colonization, algae blooms and reduced oxygen levels which can affect ecological species diversity.

Ponds and Other Small Water Bodies
Current Conditions: Ponds and other small water bodies, such as tarns and pools, occur throughout the higher elevations within the Sierra Nevada Mountains. For the purpose of this discussion, water bodies less than two acres were identified as ponds, of which there are 1,372 on the Inyo NF, with a total of 662 acres. Due to the shallow nature of these waterbodies, they are characteristically warmer during the summer months than lakes or streams. These features provide breeding habitat for the Yosemite toad and Pacific chorus frogs, which prefer meadow edges without deep water or adjacent steep terrain (Davidson 2005). Ponds are sometimes ephemeral, drying up before the end of the summer season. In an apparent adaption to the ephemeral nature of these water sources, Yosemite toad and tree frog larvae (tadpoles) metamorphose quickly into young adults allowing them to mobilize and search for other water sources, if needed.

The current condition of ponds throughout the Forest is poorly documented, mainly because most ponds occur within the Wilderness where few authorized activities occur. Impacts to these features have been observed from recreation use and impacts from people and livestock or packstock grazing. The Trail and Commercial Pack Stock Management in the Ansel Adams and John Muir Wildernesses decision took into consideration the protection and condition improvement of meadows with associated ponds. Implementation of this management plan is aimed at improving conditions of these aquatic features.

Trends: The main factor of the persistence of these ponds is the local and annual climate as related to precipitation. The eastern side of the Sierra Nevada receives less rainfall and snow fall than the west side, and during dry years, or several “dry” years, small ponds, tarns and streams in the upper elevations will dry. The anticipated effects of climate change predict that there will be less water during the coming years, and higher temperatures, putting these small features at risk of drying for longer periods of time. Increased temperatures may affect small water bodies significantly, increasing growth of algae which can have detrimental effects to species in ponds. This may have long-term effects on local populations of Yosemite toad and other species that use the ponds, such as the small fairy shrimp. How long these species can persist without water in critical breeding ponds is unknown.

Springs and Seeps
Current Conditions: Springs are scattered throughout the Inyo NF, throughout different habitats. From existing in dry, barren slopes to the center of a wet meadow, springs provide unique habitats as varied as the species that occupy them. Existing information indicates that there are approximately 508 springs on the Forest. From Sada et al 2002, “Springs are relatively small aquatic and riparian systems that are maintained by groundwater flowing onto the land surface through natural processes. They are distinct from other aquatic systems because their water temperature is relatively constant (at least near their source), they depend on subterranean flow through aquifers, they provide the only water over vast areas and are therefore ‘biodiversity hotspots’, and many support obligatory, spring-dwelling species…” Springs on the Inyo NF can either flow and sink into the surrounding sand, or flow and join other water sources to provide fresh, cool water to stream systems. The tiny springsnail occupy only the portion of the spring where it first emits from the ground and then only a few meters from the mouth of the spring (Hershler et al 1998). Salamanders tend to occupy “seeps”, a type of spring that does not form a channel or pool. Seeps tend to keep an area moist, but not wet, a condition suitable for salamanders. Many mosses and other plants occupy spring sites, thriving on the cool and humid conditions. Currently, the Owens tui chub is exclusively restricted to springs and spring channels because of their separation from mainstem systems that have been planted with non-native predatory fish.

The persistence of springsnails in these systems indicates that these springs have persisted even through some of the longer dry periods of the region in the last 10,000 years (Hershler et al 1998). Although lake levels in Tioga Lake, Mono Lake and even Owens Lake show evidence of extreme drought conditions in the past (Stine 1994), springs must have continued to flow in order to maintain the stable habitat that springsnails depend.

There are no recent inventories of springs or seeps on the Forest that relate to current condition of the resource. Stressors on these systems include spring development, recreation use, concentrated livestock grazing use, diversions and unauthorized OHV use. Groundwater pumping can affect springs even miles away from the pumping source, causing springs to cease flowing. Spring condition was an issue that was addressed in the Crowley Allotments Grazing Management Project (2007) which identified and set up protections for many springs within the projects area. Many of those projects, including fencing or removing cattle from over-used springs, have been implemented. Expected results are the improvement of spring resources throughout the Crowley Basin.

Trends: Under effective grazing management, springs are expected to show an upward trend across the Forest. Many springs have been fenced from livestock use, and this is expected to improve function and condition of these springs. This upward trend in these managed springs will improve water quality, although water quantity will show seasonal fluctuations, depending on water sources. Temperatures at the spring source will most likely remain stable as they are influenced by sub-terrain temperatures. It is also expected that even with predicted decrease in water throughout the area due to climate change, springs will persist, but may be the only water sources available for animals. Springs could receive additional impacts from species such as mule deer, burros, wild horses, and other animals as other stream sources dry, especially in the White and Inyo mountains. Careful management of these features is necessary to ensure their continued quality and persistence.

Lotic Ecosystems
Lotic systems incorporate those water sources that flow, including rivers, streams, creeks, regardless of the habitat they flow through. The ecological condition of streams is a management priority when considering activities that may impact stream resources. Primary impacts to streams include above normal sedimentation loads, changes in flow volume and timing, changes in chemical composition and temperature. Management activities can be altered to reduce impacts to streams.

Larger Riverine Systems
Current Conditions: Large rivers like those on the west side of the Sierra Nevada Mountains are predominately absent from the eastern Sierra Nevada Mountains, but several large streams fit the function of valley bottom rivers that receive water from multiple smaller scale watersheds. These include the upper Owens River through Long Valley, the South Fork Kern River, and the San Joaquin River through Reds Meadow. These systems usually provide a consistent, abundant flow of water throughout the year, and support more complex faunal ecosystems. For Example, the Owens River supported a guild of five different slow-water fish species (ie,Owens tui chub, Long Valley and Owens speckled dace, Owens pupfish, and Owens sucker; see the Flat Gradient Stream section below). On the eastern side of the Sierra Nevada, these rivers, such as the Owens River, terminate into basins, without connecting to the ocean. The South Fork Kern River flows to the west side of the Sierra Nevada Mountains in the southern part of the range, and the San Joaquin River flows to the Central Valley in California.

The macro-invertebrate stream condition sampling completed by the State of California and Region 5 Forest Service, showed that stream conditions varied based on the location of the sample. Within the Inyo National Forest, two sites rated as very poor, one site as poor, one site as good and two sites as excellent (Bioregional Assessment, Chapter 1 topic paper). Sites rated as poor and very poor were located near popular recreation sites. Some water quality sampling has been conducted across the Forest, as described in Chapter 2. Aside from water quality, streams are also rated on their channel function. For the most part, stream systems on the Forest function at desired conditions except in areas where streams are incised below the water table and are not able to access their flood plains. Drivers to the system depend on local annual variation of climate as related to precipitation, either rain or snow. Stressors on the system include dams and controlled flows, ineffectively managed grazing systems, recreation uses, diversions, and loss of connectivity between systems. However, in the case of the Kern River, barriers are needed to exclude non-native brown and rainbow trout from encroaching and competing with California golden trout. Barriers affect local geomorphology and hydrology, which may have a factor in causing instability in meadow systems below the barrier by intercepting much needed meadow-building sediment. Lack of these nutrients downstream and the effect of limiting flooding can impede the vigor of streambank vegetation.

Trends: Recreation activities contribute the greatest impact on these systems, as most campgrounds and popular recreation areas occur near these systems. These impacts are not expected to diminish in the near future, and may increase with use. Improved grazing management will continue and is predicted to move aquatic resources in an upward trend for these systems, except in areas like Monache Meadow where stream equilibrium has not been enough achieved and vegetation has not yet been re-established. With observed changes in seasonal flow, peak flow run-off may occur earlier, which may affect life cycles of resident fish, but not enough to change species composition in the next 20 years.

Flat Gradient, Meadow-Associated Streams
Current Conditions: Meadow streams are a unique feature on the landscape that draws the attention of many. Meadows are typically formed by the deposition of sediment, sand and soils by the stream, which carries these materials from the upper watershed. As the stream hits the flatter, wider geomorphologic feature, the water slows down and deposits the finer materials. The accumulation of these sediments provides the base for the formation of the meadow, by providing a nutrient-rich base for plants to grow and flourish. The accumulation of rich soils in the valley bottoms provides many resources to animals and humans alike. The constant dynamic nature of the river or stream through the meadow maintains a diversity of plant species. The usually deep and narrow channels that flow through the meadows provide high quality habitat for fish and other native amphibian species. Stream channels in healthy functioning meadow systems will access floodplains on a regular basis, dropping more sediment on these flat plains and re-charging the system with new organic matter for growing plants, much like adding compost to the garden in the spring. Streams that have become incised are not able to access the floodplains or to dissipate the energy that is caused by increased volume of the stream.

There are approximately 194 miles of streams that flow through meadows on the Forest. Meadows across the Inyo National Forest share similar geomorphologic characteristics, but are also vary in soil depth, plant species, presence or absence of willows, channel substrate, gradient, slope, aspect, elevation, and whether they are flowing through broad valleys or through narrow mountain stringers.

The slow-moving streams through the high mountain meadows were usually refuge for the mountain yellow-legged frog. Near-by ox-bow ponds or lakes provided breeding habitat for frogs and rearing habitat for tadpoles. The portions of these streams that flowed through Long Valley (surrounding Crowley Lake) and Owens Valley provided habitat for the native Owens tui chub, Long Valley and Owens speckled dace, Owens pupfish and Owens sucker. Stream sections in the valley also provided habitat for the Anodonta californiensis, a freshwater mussel that depends on non-salmonid fish for the early stage of its life cycle. These stream types now provide excellent habitat for the introduced rainbow, brook and brown trout throughout the Forest. An exception to this is the meadows segments of the South Fork Kern River, which is the native home-range of the California golden trout. The South Fork Kern River provided habitat for the Margaritifera falcata, which is a species of freshwater mussel that depends only on salmonid fish species for a portion of its lifecycle.

Meadow reaches of streams can also be highly impacted by activities within the riparian zone, the primary activity on the Inyo NF within meadows is livestock grazing and recreation uses. Impacts associated with ineffectively managed livestock grazing have been well documented in these types of meadow systems (Platts, WS, 1991). Impacts include loss of streamside vegetation, conversion of vegetation types, increased width and reduced depth of stream channels, increased temperatures, increased fines, reduced macro-invertebrate food supply, decreased shade and loss of complexity within the stream channel. Understanding meadow systems and the grazing habits of livestock makes it possible to manage grazing to allow for meadows to meet its potential to provide in-stream aquatic habitat features important for fish and other aquatic dwelling species (USDA 2011).

Management of meadow-associated streams is a priority on the Inyo NF. Recent assessments using the Proper Functioning Condition Protocol, which looks at stream channel function of streams reaches through meadows, showed that 17 out of 104 (15%) reaches assessed were not functioning at desired conditions, or in an upward trend from previous assessments. Decisions resulting from the Environmental Assessments for the Crowley, White Mountain, Mono area grazing allotments set grazing standards aimed at improving conditions of streams that had identified issues, such as lowered species composition, degraded banks, active incisions with lowered water tables, etc. Follow-up monitoring has not yet been initiated on these allotments to assess condition of the streams within the meadows. The recent Travel Management Plan addressed unauthorized use through meadow systems on the Forest with the intent of restoring the function of these meadows. There is no complete, comprehensive condition assessment for all stream-meadow systems across the Forest. Activities that produce excess sediment include grazing, angler and recreation user-trails, presence and use of roads, prescribed fire, timber and vegetation management activities.

Table 15. Proper Functioning Condition ratings across the Forest for meadow streams.
Proper Functioning Condition Ratings
Desert Group
White Mountain Group
Crowley Lake Group
Kern Plateau Group
Mono Lake Area Group
Total
PFC
6
4
24
33
0
67
FAR – upward
0
2
2
17
0
21
FAR – trend not apparent
0
1
4
4
0
9
FAR - downward
0
1
8
3
0
12
Non-functional
0
0
3
2
0
5

Trends: As more focus is given to these stream system types as related to improved grazing management, reduction of illegal off-road use, reduction of miles of roads, management of wilderness recreation use in meadow areas, it is anticipated that these systems will improve in functionality, vegetation vigor, sediment reduction and species diversity. Such changes are expected to result in an improvement of macro-invertebrate monitoring scores and water quality. Earlier spring run-off dates as affected by climate models may affect fish life cycles, but in the next 20 years systems are not expected to change enough to affect fish species structure within the stream. However, as Forests become more popular for recreation and resource uses, impacts may be expected to increase.

Higher Gradient Non-Meadow-Associated Streams
Current Conditions: Streams that flow through either forested or steep, usually rocky, areas exhibit different characteristics and fulfill different habitat niches for different species. Water flow is faster, the substrate is larger and provides the structure of the channel. Large woody debris, such as logs and root wads are typically important structural and biotic components of this stream reach type (ref.wood debris). High gradient streams vary in size and is usually related to their location within the watershed. Larger stream system examples are those that flow out of the eastern slopes of the Sierra Nevada Mountains into the Owens Valley, including Pine Creek, Bishop Creek, Big Pine Creek, Rock Creek, etc. Approximately 7% of perennial streams on the Inyo National Forest, as discussed in Chapter 2 – Water Resources and Chapter 8 - Water Uses, have controlled flows due to dams or diversions along the stream path, associated with reservoirs. Some examples of streams that have modified flow regimes due to dams or diversions include South and North forks of Bishop Creek, Rock Creek, Rush Creek, Convict Creek and Mill Creek. Altered flow regimes of streams along with physical barriers such as dams can have detrimental effects on upstream migrating fish and other aquatic species that have evolved in these systems prior to dams, an example being the salmon. However, within the Forest, except for the California golden trout in the South Fork Kern River, there are no native fish or amphibians that inhabit these higher gradient stream systems or use them as migration/dispersal corridors. Aquatic macro-invertebrate species depend on a consistent water source, and community structure, species richness, and specific species can be affected by the altered flows, temperatures and sediment budgets of dammed streams.

Higher gradient stream reaches are subject to impacts that contribute sediment into the system, which is usually deposited in the lower, flatter (depositional) reaches of the stream. See Chapter 2 – Soil Resources for information about sediment sources on the Forest.
Many of the stream systems on the Forest were fishless prior to stocking of non-native trout, except for the South Fork Kern River and Golden Trout Creek and their tributaries which are the native range of the California golden trout. Native species that are found in these systems include a variety of stream-dwelling macro-invertebrates, or the aquatic life-cycle stage of many aquatic insects, such as caddis flies, may flies, stone flies, etc. The guilds of macro-invertebrates are used as an indicator of stream health.

Currently, these stream system types provide good habitat for introduced trout such as rainbow and brown trout, which thrive in the cool waters and prey on the abundant macro-invertebrates. Fish that are native to the Owens River and truibutaries, such as tui chub, dace and pupfish, prefer slow moving or even ponded water environs as opposed to fast-flowing higher gradient systems. Although the Owens sucker can tolerate some current, it would not typically be found in steeper gradient systems.

Documented impacts to these stream systems include unauthorized “recreation” dams that are observed near and through campgrounds. Pools are created behind these small but effective dams, trapping sediment, causing bank erosion, affecting local movements of fish, etc.(Inyo NF files). Other stream segments are affected by upstream dams that regulate flow, which affects flow patterns and creates cooler temperatures, which makes conditions desirable for non-native trout but alters native macro-invertebrate communities. Grazing, road density, recreation use, forest vegetation management activities, ski-areas and other sources contribute excess sediment to these systems.

Trends: Recreation activities, vegetation management projects, dams and diversions projects contribute the greatest impact on these systems. These impacts are not expected to diminish in the near future, and may increase with use. With observed changes in seasonal flow, peak flow run-off may occur earlier, which may affect life cycles of resident fish, but not enough to change species composition in the next 20 years.

Special Management Areas for Aquatic Ecosystems
Critical Aquatic Refuges
Critical Aquatic Refuges (CARS) were designated in the 2004 Sierra Nevada Forest Plan Amendment to identify and maintain aquatic features on the landscape that are critical for the maintenance of rare aquatic species habitats.

O’Harrel CAR is identified for the recovery of the threatened Lahontan cutthroat trout. This is a small stream that flows from the Glass Mountains towards Crowley Lake, but terminates prior to the confluence of any other water body. This condition has made it desirable to manage for a fish species that may face competition from other fish species. Populations of this fish were stable over the longer trend, however in recent years visual surveys revealed no fish. However, in 2012, an electroshocking exercise produced a total of 4 fish throughout the typically occupied stream reach.

Habitat for the Mountain yellow-legged frog has been identified in the Dry Creek/Crooked Creek Meadow CAR, the Baker Creek CAR, the Gable Lakes CAR and Harvey Monroe Hall RNA CAR. Except for Gable Lakes, all of the populations within the three other CARs have succumbed to the effects of a lethal fungal infection, leaving these three areas devoid of frogs (see Chapter 5 – At Risk Species for more information about Mountain yellow-legged frog).

The Golden Trout/Volcano Creeks CAR provides habitat for the California golden trout and encompasses the entire watershed of this stream system. California golden trout are numerous in these CARs (CDFG 2008 and 2009).

Several CARs are identified as providing habitat for several species of endemic salamanders, including the Mount Lyell salamander (MLS), Inyo Mountain slender salamander (IMSS), and Batracheoseps sp (since described as Kern Plateau Slender Salamander, Batracheoseps robustus))(OSS). These include the Elderberry Canyon CAR (MLS), Olancha CAR (MLS and OSS), Haiwee Canyon CAR (OSS), Lead Canyon CAR (IMSS) and Barrel Springs CAR (IMSS). Although no comprehensive surveys have been conducted, there are reports that the habitat appears to be intact in several of these areas and salamanders have been observed (personal communication, Ceal Klingler).

The Wong’s springsnail has identified habitat within the Elderberry Canyon and Barrel Springs CARs. Restoration efforts to remove off-road traffic were completed in the Barrel Springs area in the early 2000’s.

Little Hot Creek CAR provides habitat for the Endangered Owens tui chub. Work is ongoing in this watershed to reduce the amount of sediment entering the stream and pond from adjacent native surface roads.

Cottonwood Creek CAR is a refuge site for the Threatened Paiute cutthroat trout. Grazing has been suspended in this area by vacating the allotment, allowing for a more rapid recovery of the stream banks. Several efforts to increase spawning gravel within the system have been undertaken with some positive results observed. In 2009, the CAR became part of the designated White Mountain Wilderness area.

Yosemite toad habitat is identified within the Crater Meadow CAR, Upper Convict/McGee CAR and the Harvey Monroe Hall CAR. Impacts associated with commercial packstock use in Yosemite toad habitat in the Upper Convict/McGee and Crater Meadow CARs was analyzed and addressed in the 2005 Trail and Commercial Pack Stock Management in the Ansel Adams and John Muir Wildernesses Project. Implementation of the 205 decision has since been enjoined.

The Glass Creek/Deadman Creek CAR is a complex of numerous high quality, special aquatic habitats, and according to the 2004 Sierra Nevada Plan Amendment, mountain yellow-legged frog was found there in 1993 surveys. No frogs have been identified in the area since, but a population of Yosemite toad occurs in the Glass Creek meadows. Since allocated as a CAR in the 2004 Fraemwork, this area has been designated as Wilderness and the stream is designated as a Wild and Scenic River.

Riparian Conservation Areas
Riparian Conservation Areas (RCAs) are special management corridors established in the 2004 Sierra Nevada Forest Plan Amendment that are managed to maintain or restore the structure and function of aquatic, riparian and meadow ecosystems. The intent of management direction for RCAs is to (1) preserve, enhance and restore habitat for riparian and aquatic-dependent species; (2) ensure that water quality is maintained or restored; (3) enhance habitat conservation for species associated within the transition zone between upslope and riparian areas; and (4) provide greater connectivity within the watershed. RCAs are delineated and managed consistent with riparian conservation objectives. The specific management direction is described in the Sierra Nevada Forest Plan Amendment FEIS, Record of Decision, Appendix A. The Framework established a 300 foot buffer on either side of the stream on perennial stream systems and 150 feet on both sides of an ephemeral channel. Other widths are identified for other special aquatic features.

Wild and Scenic Rivers
Several Wild and Scenic Rivers have been designated throughout the Forest. These include the South Fork Kern River, Cottonwood Creek, and Owens River Headwaters (Deadman and Glass Creeks, and part of the Owens River). See Chapter 15 – Designated Areas, for more information about the Forest’s Wild and Scenic Rivers. Cottonwood Creek was designated in part for its unique feature of the Threatened Paiute cutthroat trout, a refuge population that is maintained in the event of a catastrophic event that could eliminate all fish in their native habitat. The South Fork of the Kern River provides habitat to California’s State Fish, the California golden trout, and the Owens River Headwaters is a free-flowing stream that provides habitat for Yosemite toad in the upper watershed of Glass Creek.

References

California Department of Fish and Game. 2008. Golden Trout Wilderness 2008 Summary Report, Golden Trout Creek, Siberian Creek, Stokes Stringer and Mulkey Creek.
California Department of Fish and Game. 2009. South Fork Kern River 2009 Summary Report. Heritage and Wild Trout Program.
Davidson, C and GM Fellers. 2005. Bufo canorus in Amphibian Declines, The Conservation Status of United States Species. Edited by Lannoo. University of California Press. Pp 400-401.
Epanchin, P.N. RA Knapp, SP Lawler. 2010. Nonnative trout impact an alpine-nesting bird by altering aquatic-insect subsidies. Ecology 91(8) pp. 2406-2415.
Hershler, R and DW Sada. 1998. Biogeography of Great Basin Aquatic Snails of the GenusPyrgulopsis. Smithsonian Contributions to the Earth Sciences, Number 33.
Knapp, RA, DM Boiano, VT Bredenburg. 2007. Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa). Biological Conservation 135, pp. 11-20.
Platts, William S. 1991. Livestock Grazing, Chapter 11. In Influences of Forest and Rangeland Management on Salmonid Fishes and Their Habitats. Edited by William Meehan. American Fisheries Society Special Publication 19, Bethesda, MD, 1991.
Sada, DW and KF Pohlmann. 2002. Spring Inventory and Monitoring Protocols. Conference Proceedings: Spring-fed Wetlands: Important Scientific and Cultural Resources of the Intermountain Region.
Stine, Scott. 1994. Extreme and persistent drought in California and Patagonia during mediaeval time. Nature Volume 369. pp 546-549.
USDA, 2011. Conservation Benefits of Rangeland Practices. Assessment, Recommendations, and Knowledge Gaps. Edited by David D. Briske USDA, NRCS.


Riparian Ecosystems

Introduction

Riparian ecosystems are a critically important component of biodiversity, supporting a higher level of species diversity than most terrestrial ecosystems. They serve in part as a link between aquatic and terrestrial ecosystems, and play numerous important roles within the broader landscape, such as providing for wildlife habitat (including habitat corridors), nutrient cycling, and proper watershed function. They are also attractive for many uses such as grazing, camping, fishing, hydropower production, etc. In the context of the overall landscape, they occupy a very small percentage of the Forest, particularly with regard to their importance. Kattelmann and Embury (1996, cited in Sawyer 2013), in the draft NRV analysis for riparian ecosystems, note that riparian vegetation currently makes up less than 1% of the Sierra Nevada bioregion. More detailed information regarding the importance of riparian ecosystems, and their function, composition, and structure in the bioregion can be found in the Science Synthesis (Long 2013; Hunsaker & Long 2013), the draft Natural Range of Variability (NRV) Assessments for the bioregion (Stewart 2013; Gross & Coppoletta 2013), and the draft Bioregional Assessment Chapter 1 topic paper.

The riparian ecosystems on the Inyo NF are typically at the upper end of the watershed, and serve as corridors for movement of wildlife species and people, as well as invasive riparian and aquatic species between the upper and lower elevations in the Eastern Sierra, and between lands managed by the Inyo NF and other entities such as the Bureau of Land Management (BLM) and the Los Angeles Department of Water and Power (LADWP). Riparian areas occur in every Ecological Subsection and assessment type described in the Terrestrial Ecosystems section, at all elevations.

Riparian ecosystems are differentiated into riparian meadow and riparian non-meadow systems in the draft Bioregional Assessment Chapter 1 topic paper. In that topic paper, riparian meadows are defined as those areas where herbaceous vegetation is dominant, with sedges, rushes, and grasses being common. Willows, alders, cottonwoods and other woody vegetation are dominant in riparian non-meadow systems, though there is often also an herbaceous component.

The Inyo NF riparian ecosystems are also be differentiated into meadow and non-meadow riparian ecosystems, utilizing the series identified in the Forest Terrestrial Ecological Unit Inventory (TEUI). The Forest TEUI provides the most accurate forestwide mapping of riparian ecosystems; however, due to the large scale of the TEUI mapping effort, many of the smaller riparian areas are not included here. There are project level data sets, e.g. John Muir/Ansel Adams Pack Stock 2005 Environmental Impact Statement meadow layer, Kern Plateau Land Type Phase Ecological Inventory, that provide more detailed mapping at a finer scale, but they are each limited to specific areas on the Forest. There is no forestwide data set for riparian areas that captures all of these ecosystems spatially. The following table lists the TEUI series included in the meadow and non-meadow riparian types.

Table 16. TEUI series included within meadow and non-meadow riparian ecosystems.
Meadow Riparian
Non-meadow Riparian
ARCAB1 Silver sagebrush
BEOC Water birch
ARRO1 Rothrock sagebrush
POBAT Black cottonwood
Dry Meadow
POFR Fremont cottonwood
Moist Meadow
QUKE Black oak
Wet Meadow
Salix non-meadow2
Seep

Salix meadow2 Willow meadow

1While ARCAB and ARRO are shrub types, and are included in the sagebrush shrub assessment type in the Terrestrial Ecosystems discussion for the purpose of comparison with the sagebrush NRV analysis, there is typically significant meadow herbaceous understory in these types; therefore, they are also included here as meadow riparian. In many cases they are considered invasive in meadows.
2Those polygons with Salix as the series were further split into meadow and non-meadow types, utilizing imagery, topography, and attributes of the polygon. Slope, herbaceous vegetation, and assocations, complexes and inclusions were reviewed to assign a Salix polygon to the meadow or non-meadow type.

Additional unique riparian ecosystems not captured by the TEUI, but available in other data sets and discussed below include fens and other groundwater dependent ecosystems, such as springs. Fens are ecosystems with hydric soils with an aquic soil moisture regime, and an accumulation of peat in the histic epipedon (Weixelman and Cooper 2009). Groundwater dependent ecosystems (GDEs) are defined as ecosystems that are supported by groundwater (USDA 2012a). Springs and seeps are the primary type of GDE other than fens that have been inventoried on the Inyo NF.

Process and Methods

Scale of Assessment
This assessment is conducted primarily at the Forest scale. Where ecosystems, including ecosystem processes, cross Forest boundaries onto adjacent lands, the condition and trend of the ecosystem on those lands will be considered as it relates to the condition and trend of that ecosystem on Forest lands, and vice versa.

This assessment addresses riparian ecosystems at a coarse scale, utilizing the meadow, non-meadow, and unique riparian types described above.

Indicators used to assess ecosystem integrity will be assessed at the landscape scale, the community scale, and/or multiple scales, as needed to portray ecosystem condition.

Information Sources
This assessment draws from information in the draft Bioregional Assessment Chapter 1 topic paper as well as the Natural Range of Variability (NRV) analyses (Gross and Coppoletta 2013; Sawyer 2013) and the Science Synthesis (Long et. al. 2013).

The primary source of information regarding the amount and distribution of riparian ecosystems is the Forest TEUI (USDA INF 2012b), particularly the Potential Natural Vegetation (PNV) component of the TEUI. See the Terrestrial Ecosystems section for a discussion of the TEUI vs. the Regional datasets used in the draft Bioregional Assessment.

Information pertaining to the condition of riparian ecosystems on the Forest is derived from the Forest and Regional range programs, as well as from fen and GDE inventories conducted on the Forest.

Indicators
Indicators are identified in the Current Conditions sections for meadow and non-meadow riparian systems. The indicators are intended to be measurable, and focused on those attributes for which data is available.

Current Conditions

Meadow Riparian
Information on the current condition of meadow riparian ecosystems on the Inyo NF comes primarily from range condition data, e.g. Forest Plan Amendment 6 vegetation data conducted for the Forest range program, and long term monitoring plots established for key area meadows under the Region 5 Range Long Term Monitoring Project. Fen data is based on inventories conducted in conjunction with the Ansel Adams/John Muir Wilderness Pack Station EIS and Kern Plateau grazing analysis, along with general Forest fen inventories. Groundwater Dependent Ecosystems data also provides information on a small subset of meadow riparian systems on the Forest.

The following table of indicators displays factors relevant to the current condition of meadow riparian ecosystems across the Inyo National Forest. Refer to the draft Bioregional Assessment Chapter 1 topic paper and to the Forest’s Chapter 8 – Range topic paper for more detailed information on the location and significance of the various methods for assessing meadow and streambank condition and their relevance to ecological integrity of these riparian systems.

Table 17. Indicators for meadow riparian ecosystems
Attribute being measured
Indicator
Unit
Value
Biodiversity
Proportion of landscape occupied by meadow riparian
Percent
<1%
Ecological status of vegetation condition
Proportion of Region 5 Range plots by seral stage
Percent
31% PNV1
49% Late Seral
20% Mid Seral
0% Early Seral
Ecological status of vegetation condition
Amendment 6 meadow vegetation condition ratings
% of ratings in each condition category
35% Excellent
35% Good
23% Fair
7% Poor
Streambank condition
PFC ratings
% of ratings in each condition category
56% PFC
19% FAR – upward
8% FAR – trend not apparent
11% FAR – downward
5% Non-functional
Fine scale biodiversity
Fen PFC ratings
% of ratings in each condition category
39% PFC
20% FAR – upward
39% FAR – trend not apparent
2% FAR – downward
0% Non-functional
Conifer or upland shrub encroachment
Abundance of conifer or upland shrubs in meadows
% cover
See Fryjoff – Hung below
Ecosystem function – erosion
Proportion bare ground
% bare ground
See Fryjoff-Hung below
Ecosystem function – invasives
Number of invasive species
Count
NRIS
1PNV = Potential Natural Vegetation

Data for the riparian ecosystems on the Forest is limited, as it is across the bioregion. The indicators above focus on range condition data and invasive species data. It is important to note that the vegetation and streambank condition data was gathered for the purpose of monitoring range condition on grazing allotments. Forest Amendment 6 transects were located in range key areas. A key area is defined as a sample area selected to be representative of forage utilization on a unit or allotment. The Regional range long term monitoring plots were located in areas most likely to show change and transition, and are not necessarily reflective of the overall condition of an area. As such, these condition ratings are likely not representative of meadow systems on the Forest as a whole.

Seventy-seven Regional long term monitoring plots were conducted on the Forest. The data presented is based on the most recent reading of each plot, some of which are more than 5 years old.

The Amendment 6 vegetation condition ratings are summarized from sixty-nine vegetation condition transects completed across the Forest. One hundred fourteen Proper Functioning Condition (PFC) assessments were completed. Part of the PFC rating is based on the condition of streambank vegetation.

Fryjoff-Hung (2013) conducted surveys from 2010 - 2012 across six National Forests in the Sierra Nevada and Southern Cascades (see Bioregional Assessment Chapter 1 topic paper) to better understand and quantify the potential increase in water-storage capacity achievable through restoration of eroded meadows on National Forest System lands throughout the Sierra Nevada. Unlike the Forest and Regional range data, the meadows were a random sample of meadows across the bioregion, and the entire meadow was sampled. They recorded information on vegetation cover, bare ground, and tree and shrub encroachment, among other attributes. Ten of the sites were located on the Inyo NF, in the Glass Mountains and Sierra Nevada, from Rodeo Grounds Meadow in the north to Dutch Meadow on the Kern Plateau. The categories used to rate vegetation cover, bare ground, and conifer or upland shrub encroachment are shown in the following table.

Table 18. Categories used to rate vegetation cover, bare ground, and conifer or upland shrub encroachment
Parameter
Condition Category

Natural
Slightly impacted
Moderately impacted
Heavily impacted
Vegetation Cover
Graminoids 75-100% of area covered by vegetation
50-75% graminoid cover
Forbs dominate. 25-50% graminoid cover.
Forbs dominate. <25% graminoid cover.
Bare Ground
Bare ground covers less than 5% of meadow area.
Bare ground covers 5-10% of meadow area
Bare ground covers 10-15% of meadow area
Bare ground covers > 15% of meadow area
Conifer or Upland Shrub Encroachment
No upland shrub or conifer encroachment.
Few encroaching upland species; <10% of total meadow area
Encroaching upland species cover 10-20% of total meadow area
Encroaching upland species cover >20% of total meadow area

Summarized results for the ten meadows on the Inyo NF studied by Fryjoff-Hung are presented below.

Table 19. Results for the ten meadows on the Inyo NF studied by Fryjoff-Hung
Condition Category
Vegetation Cover (# plots)
Bare Ground (# plots)
Encroachment (# plots)
Natural
1
2
2
Slightly impacted
8
7
1
Moderately impacted
0
1
6
Heavily impacted
1
0
1

Of the 8 plots where encroachment was recorded, 4 were sagebrush and 4 were conifers. As noted in the draft Bioregional Assessment Chapter 1 topic paper, conifer encroachment can be attributed to one or more of several causes, including climate effects, fire suppression, and grazing. The NRV analysis for subalpine conifer notes that “the historic frequency and extent of lodgepole pine encroachment into meadows and aspen stands of the Sierra Nevada are poorly understood” (Meyer 2013). Millar (2004) correlated conifer “invasion” in 10 central Sierra Nevada meadows (7 of these on the Inyo NF) with long-term fluctuations in weather patterns, specifically, a 30 year period with consistently drier weather and low soil moisture in the mid-20th century.

The potential causes of sagebrush encroachment into montane meadows are addressed in the Science Synthesis (Long 2013) and the draft NRV analysis for Meadows (Gross and Coppoletta 2013). The relationships between historic and recent livestock grazing, changes in climate, stream incision, and other factors affecting sagebrush invasion are complex, and may vary between Sierran and Great Basin systems. As evidenced by the meadows surveyed by Fryjoff-Hung, as well as the range data collected on the Forest, sagebrush encroachment is currently an issue in meadows on the Inyo NF, and can have a significant effect on vegetation productivity in these areas. See the Ch. 8 - Range discussion for more information on grazing use in meadows on the Inyo NF.

Debenedetti and Parsons (1979), Millar (1996), and Dull (1999) (all as cited in Gross and Coppoletta 2013) suggest that fires were less common in meadows compared to the surrounding forests and where they did occur they were localized within the meadow. Dull (1999, as cited in Gross and Coppoletta 2013) found a charcoal horizon in Monache Meadow which likely represents a major forest fire event(s) in the upland areas surrounding the meadow, but there is little evidence that the fire(s) burned the meadow surface. Gross and Coppoletta also report that interior meadow fires were more commonly of low severity, while the meadow-forest ecotone would have been of higher severity. Across the bioregion, current fire return intervals for the meadow-forest boundary are likely longer than during the NRV period (Gross and Coppoletta 2013). This may be the case in some meadows on the Inyo NF, though specific examples for the Forest are not available.

With the increase in OHV use and technology in recent years, roads have proliferated within meadow (and other) ecosystems. In wet meadows and moist meadows, early season use has resulted in the proliferation of routes as drivers steer clear to avoid “mud bogs”, creating new routes in the process. In response to this, and as a part of ongoing restoration work, the Forest has made significant efforts during this past planning cycle to stabilize or reroute roads and trails out of meadow ecosystems.

The primary invasive plant species of concern that occur in meadow ecosystems on the Forest include bull thistle (Cirsium vulgare), dandelion (Taraxacum officinale), mullein (Verbascum thapsus), and spotted knapweed (Centaurea stoebe ssp. micranthos). These species can impact native meadow ecosystems in many ways, including reducing biodiversity and productivity, and affecting soil stability. Approximately 175 acres of meadow riparian are occupied by one or more non-native plant species.

Additional information regarding riparian meadow and non-meadow ecosystems on the Forest is available from the Groundwater Dependent Ecosystems (GDE) surveys conducted in 2009 and 2010. Nineteen spring areas were surveyed across the Forest. Of these, thirteen are considered meadow riparian ecosystems and six are considered non-meadow riparian ecosystems. For each GDE survey, a qualitative assessment of condition is completed through a series of questions related to hydrology, vegetation and soils. A “no” for any of the seven vegetation questions indicates an issue with regard to the condition of the wetland vegetation, e.g. plant species present are not wetland species, wetland plants don’t exhibit high vigor, vegetation cover is not adequate to prevent erosion, etc. Of the thirteen meadow GDEs surveyed, six had no vegetation issues identified, i.e. no vegetation questions were answered with a “no”, two sites had only one issue identified, and five GDEs had two or three vegetation issues identified (out of seven questions) that could affect the condition of the GDE.

Fens are a special type of GDE and meadow riparian ecosystem. Fens play an important role in nutrient cycling and groundwater discharge, provide habitat for rare species, and are a major sink for atmospheric carbon (Weixelman and Cooper 2009).

Fen surveys have been conducted in selected locations across the Forest, a majority of these in the John Muir, Ansel Adams, and Golden Trout Wildernesses, in conjunction with pack stock and/or grazing analyses. As such, and similar to the range condition data, these surveys targeted areas where livestock use occurs, rather than being a random sample that would represent a broader range of conditions across the Forest. Approximately 120 fens have been confirmed on the Inyo NF. Fen condition can be evaluated using the Proper Functioning Condition protocol for fens (Weixelman and Cooper 2009). PFC assessments have been completed for 44 fens on the Forest, all of these on the Kern Plateau.

Non-Meadow Riparian
Non-meadow riparian areas include shrub- or tree-dominated springs, as well as the stream systems on the Forest. Much less data is available for non-meadow riparian ecosystems as compared to meadow ecosystems. Non-meadow riparian areas typically are not the focus of grazing use; hence, little to no range condition data is collected for these areas.

The primary influence on non-meadow riparian ecosystems on the Inyo NF is the manipulation of water. Activities and uses that change the amount, quality, or seasonality of water can significantly affect the riparian vegetation dependent on a given stream system. Chapter 2 – Water Resources provides a description of water flow and quantity, while Chapter 8 – Water Uses provides an overview of the diversions and dams on the Forest. Water management activities conducted by Southern California Edison and the Los Angeles Department of Water and Power have had the most influence on the condition of non-meadow riparian ecosystems on the Forest. The draft Bioregional Assessment Chapter 1 topic paper provides more detail on the specific effects of dams and diversions.

De-watering has had the most significant impact on streamside riparian systems in the recent past, such as Bishop Creek, Rush Creek, and Lee Vining Creek (Stine et al 1983, as cited in Sawyer 2013). Changes in regulation of these systems have re-established flows, and riparian vegetation is in the process of re-establishing on the streambanks and floodplains (McBain and Trush, Inc. and Ross Taylor and Associates 2010; Read and Sada 2010). Changes in riparian vegetation associated with changes in flow other than de-watering are more subtle, and are influenced by other factors such as geomorphology of the site, and spring influences.

The fire regime in non-meadow riparian ecosystems and the consequent effects of fire suppression in these systems are variable. Narrower, more incised streams reportedly mirror adjacent upland characteristics, e.g. if the adjacent upland has a short fire return interval that has been affected by years of fire suppression, the riparian area is likely similarly affected, with elevated fuel loads, higher stand densities, and other conditions characteristic of ecosystems that have missed several burn events (Hunsaker and Long 2013). No specific information is available on non-meadow riparian systems on the Forest with regard to conditions affected by fire suppression.

Non-meadow riparian systems on the Forest have also been impacted by recreation use. These ecosystems have historically been attractive locations for campgrounds, fisherman user trails, recreation residences, and resorts, resulting in soil compaction and erosion, loss of vegetation productivity, introduction of competitive non-native species, and fragmentation of habitat.

Of the six non-meadow GDEs surveyed (see GDE discussion in the Meadow Riparian section above), two had no vegetation issues identified, two sites had only one issue identified, one GDE had 2 issues identified, and one had four vegetation issues identified (out of 7) that could affect the condition of the GDE. These GDEs are springs that are dominated by trees (conifers) or shrubs (primarily willows).

The NRV analysis for non-meadow riparian systems notes that riparian zones are among those areas of the Sierra Nevada most impacted by non-native invasive species, with altered riparian systems being especially vulnerable (Schwartz et al 1996, cited in Sawyer 2013). The non-native invasive plant species of greatest concern affecting non-meadow riparian ecosystems on the Forest include salt cedar (Tamarix ramosissima), perennial pepperweed (Lepidium latifolium), sweetclover (Melilotus officinalis, M. albus), bouncing bet (Saponaria officinalis) and whitetop (Lepidium appelianum, L. chalapense). Approximately 300 acres of non-meadow riparian are currently occupied by one or more non-native plant species.

Water birch and black oak are two non-meadow riparian ecosystems on the Forest that are limited in extent. Water birch is tracked by the California Natural Diversity Database (CNDDB). It is not adequately mapped at this time, but typically occurs on the relatively steep narrow stream courses emanating from the Eastern Sierra escarpment, and continues partway down the alluvial fans across lands managed by the Bureau of Land Management. The water birch community occupies approximately 2500 acres on the Inyo NF. Diversions, road crossings, fire effects, and invasive species each may have some impact on the condition of water birch communities on the Forest.

Black oak is a non-meadow riparian type that is not uncommon in the bioregion, but is restricted in the Eastern Sierra. It is more widespead on the western slope of the Sierra Nevada, and not restricted to riparian areas as it tends to be on the Inyo NF. It occurs in scattered locations in drainages and springs from Big Pine Creek south to Shepherd Creek (Giuliani 1997). Approximately 1,400 acres of black oak are mapped on the Forest. As with water birch, diversions, road crossings, fire effects, and invasive species each may have an impact on black oak communities on the Forest. The Oak Creek campground was located within a black oak stand. Both the campground and most of the oak trees were destroyed in the 2008 hyperconcentrated flow that emanated from the north fork of Oak Creek (see the Xeric Shrub section in the Terrestrial Ecosystems discussion). The Division fire of 1999 also burned a portion of the black oak community in the Division Creek drainage. Significant re-sprouting as well as seedlings have been documented following the Division fire (USFS 2007).

Mojave riparian forest, while not captured in the TEUI, is another community tracked by the CNDDB. The only reported occurrence of this type on the Forest is in the very southeastern corner, along Willow Creek on the east side of the Inyo Mountains. No information is available on the condition of this ecosystem on the Forest.

Trends

The anticipated trends for meadow and non-meadow riparian ecosystems are discussed together, as the major factors potentially influencing their ecological integrity are similar.

Climate is a strong driver of riparian ecosystems, whether meadow or non-meadow (see Chapter 3 for a more detailed discussion of potential climate change). Changes in climate that affect the quantity, quality, or seasonality of water can have significant impacts on the integrity of these systems. Warming temperatures, particularly if combined with less precipitation could have profound impacts on riparian ecosystems on the Forest in the coming years, depending on the direction and magnitude of climate change. The many demands on water for human uses, e.g. hydropower, domestic water supply, recreation, are likely to increase with increasing human population, placing additional demands on an already scarce supply.

Watershed condition, e.g. stream incision, channel stability, etc. will likely continue to affect riparian ecosystems on the Inyo NF over the next decade and more. The Forest will continue to pursue watershed restoration opportunities where feasible, but some systems, e.g. meadows with deeply incised streams, would require substantial investment to bring them back within the natural range of variability. Stable watersheds can help to ameliorate the effects of changes in water availability, due to climate change or other factors.

Invasive species will continue to be a primary issue of concern affecting meadow and non-meadow riparian ecosystems in the future. Warming temperatures will potentially influence the establishment and subsequent spread of non-native species in these areas. Current resources are wholly inadequate to stop the oncoming tide of non-native species on the Forest.

Under existing management direction and funding levels, fire suppression will continue to impact riparian ecosystems, particularly non-meadow riparian areas, resulting in a continued buildup of fuels, and subsequent stand replacing events, especially during what may become increasingly frequent and severe droughts.

References

Debenedetti, S.H. and D.J. Parsons. 1979. Natural fire in subalpine meadows – a case description from the Sierra Nevada. Journal of Forestry 77: 477-479.
Dull, R.A. 1999. Palynological evidence for 19th century grazing-induced vegetation change in the southern Sierra Nevada, California, USA. Journal of Biogeograpy 26: 899-912.
Fryjoff-Hung, Anna and J.H. Viers. 2013. Sierra Nevada Meadow Hydrology Assessment. Final Project Report to the USDA Forest Sercie Pacific Southwest Region (USFS PSW). University of California, Davis. 1114 ppd. http://meadows.ucdavis.edu/data/reports
Giuliani, Derham. 1997. Oaks of the Eastern Sierra. In: California Native Plant Society Bristlecone Chapter newsletter. Vol 17, No. 2. March 1997.
Gross, Shana and M.Coppoletta. 2013. Natural range of variability assessment for meadows in the Sierra Nevada and South Cascades. In draft. USDA Forest Service, Pacific Southwest Region. Vallejo, CA
Hunsaker, Carolyn and J.Long. 2013. Forested Riparian Areas. Chapter 6.2 in Long, Jonathan W.; Quinn-Davidson, Lenya, and Skinner, Carl N., tech. editors. Science Synthesis to support Forest Plan Revision in the Sierra Nevada and Southern Cascades. Draft Final Report. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 504 p. http://www.fs.fed.us/psw/publications/reports/psw_sciencesynthesis2013/
Kattelmann, R. and M. Embury. 1996. Riparian areas and wetlands. In: Sierra Nevada Ecosystem Project: Final Report to Congress, Vol. II, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland Resources.
Long, Jonathan, with contributions from K.Pope and K.Matthews. 2013. Wet Meadows. Chapter 6.3 in Long, Jonathan W.; Quinn-Davidson, Lenya, and Skinner, Carl N., tech. editors. Science Synthesis to support Forest Plan Revision in the Sierra Nevada and Southern Cascades. Draft Final Report. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 504 p. http://www.fs.fed.us/psw/publications/reports/psw_sciencesynthesis2013/
McBain and Trush, Inc., and Ross Taylor and Associates. 2010. Mono Basin Stream Restoration and Monitoring Program: Synthesis of Instream Flow Recommendations to the State Water Resources Control Board and the Los Angeles Department of Water and Power. Draft Report for Public Review. 134 pp.
Meyer, Marc. 2013. Natural range of variability assessment for subalpine conifer forests. In draft. USDA Forest Service, Pacific Southwest Region. Vallejo, CA.
Millar, Constance I. 1996. The Mammoth-June Ecosystem Project, Inyo National Forest. In: Sierra Nevada Ecosystem Project: Final report to Congress, Vol. II, Assessments and scientific basis for management options. Pp. 1273 – 1346. University of California, Davis: Centers for Water and Wildland Resources.
Millar, Constance I., et al. 2004. Response of subalpine conifers in the Sierra Nevada, California, USA, to 20th-century warming and decadal climate variability. Arctic, Antarctic, and Alpine Research 36.2 (2004): 181-200.
Read, Edith, and Don Sada. 2010. Bishop Hydroelectric Project (FERC No. 1394). Analysis of riparian vegetation, aquatic habitat, and fish populations, Phase 2 (Year 3) and comparison to baseline. Prepared for Southern California Edison Co., San Dimas, CA.
Sawyer, Sarah C. 2013. Natural range of variability assessment for non-meadow riparian zones. In draft. USDA Forest Service, Pacific Southwest Region. Vallejo, CA.
Schwartz, M.W., D.J. Porter, J.M. Randall, and K.E. Lyons. 1996. Impacts of nonindigenous plants. In: Sierra Nevada Ecosystem Project: Final report to Congress, Vol. II, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland Resources.
Stine, S., D. Gaines, and P. Vorster. 1983. Destruction of Riparian Systems Due to Water Development in the Mono Lake Watershed. In: Warner R.E. and K.M.Hendrix, (eds) 1984. California Riparian Systems: Ecology, Conservation, and Productive Management. Berkeley: University of California Press
Weixelman, Dave A. and D.J. Cooper. 2009. Assessing Proper Functioning Condition for Fen Areas in the Sierra Nevada and Southern Cascade Ranges in California, A User Guide. Gen. Tech. Rep. R5-TP-028. Vallejo, CA. U.S. Department of Agriculture, Forest Service, Pacific Southwest Region. 42 pp.
USDA Forest Service. 2012a. Groundwater-Dependent Ecosystems: Level II Inventory Field Guide. Inventory Methods for Project Design and Analysis. Gen. Tech. Rep. WO-86b. Washington, D.C. 124 pp.
USDA Forest Service. 2012b. Terrestrial Ecological Unit Inventory. Inyo National Forest. Report and GIS layer. Supervisor’s Office, Bishop, CA.
USDA Forest Service. 2007. Inyo National Forest. Division fire oak monitoring. Botany files, Supervisors Office, Bishop, CA.

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