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High Sierra Rocky Alpine Terrain

EVT 7067Mediterranean California Alpine Fell-Field

CES206.900GNRShrubShrubland

Summary

This ecological system occurs in limited alpine environments mostly concentrated in the Sierra Nevada but also on Mount Shasta and as far south as the Peninsular Ranges and White Mountains. Alpine elevations begin around 3500 m (10,600 feet) in the southern mountain ranges and 2700 m (8200 feet) in the southern Cascades. Wind scours fell-fields free of snow in the winter, exposing the plants to severe environmental stress. These systems typically have immature soils. Most fell-field plants are cushioned or matted, frequently succulent, flat to the ground in rosettes, and often densely hairy and thickly cutinized. Common species include Ribes cereum, Linanthus pungens (= Leptodactylon pungens), Ericameria discoidea, Castilleja nana, Minuartia nuttallii (= Arenaria nuttallii), Phlox condensata, Draba densifolia, Oxyria digyna, and Aquilegia pubescens. Plants cover 15-50%, while exposed rock makes up the rest. Fell-fields are usually nested within or adjacent to alpine tundra dry meadows.

Source: NatureServe Explorer

Environment

These are wind-scoured fell-fields that are free of snow in the winter, such as ridgetops and exposed saddles, exposing the plants to severe environmental stress. Soils on these windy unproductive sites are shallow, stony, low in organic matter, and poorly developed; wind deflation often results in a gravelly pavement. Fell is Gaelic for stone, and these are stone fields. Sites are stable for 100s to 1000s of years as soils develop. Alpine elevations begin around 3500 m (10,600 feet) in the southern Sierra Nevada and 2700 m (8200 feet) in the southern Cascades.

Source: NatureServe Explorer

Dynamics

TNC model information: Avalanches on steeper slopes where soil accumulates can cause infrequent soil-slips, which expose bare ground.

Very small burns of a few square meters (replacement fire) caused by lightning strikes are a rare disturbance, although lighting storms are frequent in those elevations. The calculation of lightning strike frequency was not based on fire-return intervals but on the number of strikes (in this case, five) per 1000 possible locations per year, thus 0.005.

Alpine rodents (pikas, marmots, etc.) cause common but generally small-scale disturbances in this system. Native herbivores (Rocky Mountain bighorn sheep, mule deer, and elk) were common in the alpine but probably did not greatly affect vegetation cover because animals move frequently as they reduce vegetation cover.

Source: NatureServe Explorer

Distribution

This system occurs in limited alpine environments mostly concentrated in the Sierra Nevada but also on Mount Shasta and as far south as the Peninsular Ranges and White Mountains.

Source: NatureServe Explorer

Ecologically Associated Plant Species

Plant species that characterize this ecosystem type, organized by vegetation stratum. These are species ecologically associated with the ecosystem, not confirmed present in any specific area.

Short shrub/sapling

Ericameria discoidea, Ribes cereum

Herb (field)

Aquilegia pubescens, Castilleja nana, Draba densifolia, Linanthus pungens, Minuartia nuttallii, Oxyria digyna, Phlox condensata

Source: NatureServe Ecological System assessment

Ecologically Associated Animals (5)

Animal species ecologically associated with this ecosystem type based on NatureServe assessment. These are species whose habitat requirements overlap with this ecosystem, not confirmed present in any specific roadless area.

Mammals (1)

Common Name	Scientific Name	G-Rank
North American Deermouse	Peromyscus maniculatus	G5

Birds (3)

Common Name	Scientific Name	G-Rank
Common Raven	Corvus corax	G5
Horned Lark	Eremophila alpestris	G5
Gray-crowned Rosy-Finch	Leucosticte tephrocotis	G5

Other (1)

Common Name	Scientific Name	G-Rank
American Pipit	Anthus rubescens	G5

Source: NatureServe Ecological System assessment

At-Risk Species Associated with this Ecosystem (1)

Species with conservation concern that are ecologically associated with this ecosystem type. G-Rank indicates global conservation status: G1 (critically imperiled) through G5 (secure). ESA status indicates U.S. Endangered Species Act listing.

Common Name	Scientific Name	G-Rank	ESA Status
Sierra Columbine	Aquilegia pubescens	G3	--

Source: NatureServe Ecological System assessment

State Conservation Ranks (3)

Subnational conservation status ranks (S-ranks) assigned by Natural Heritage Programs in each state where this ecosystem occurs. S1 indicates critically imperiled at the state level, S2 imperiled, S3 vulnerable, S4 apparently secure, and S5 secure. An ecosystem may be globally secure but imperiled in specific states at the edge of its range.

State	S-Rank
CA	SNR
NV	SNR
OR	SNR

Roadless Areas (2)

Inventoried Roadless Areas where this ecosystem is present, identified from LANDFIRE 2024 Existing Vegetation Type spatial analysis. Coverage indicates the proportion of each area occupied by this ecosystem type.

California (2)

Area	Forest	Coverage	Hectares
Hoover - Virginia Lks	Humboldt-Toiyabe National Forest	1.6%	31.95
Log Cabin Saddlebag	Inyo National Forest	0.9%	57.96

Methodology and Data Sources

Ecosystem classification: Ecosystems are classified using the LANDFIRE 2024 Existing Vegetation Type (EVT) layer, mapped to NatureServe Terrestrial Ecological Systems via a curated crosswalk. Each EVT is linked to the USNVC (U.S. National Vegetation Classification) hierarchy through pixel-level co-occurrence analysis of LANDFIRE EVT and NatureServe IVC Group rasters across all roadless areas.

Vegetation coverage: Coverage percentages and hectares are derived from zonal statistics of the LANDFIRE 2024 EVT raster intersected with roadless area boundaries.

Ecosystem narratives and community species: Sourced from the NatureServe Explorer API, representing professional ecological assessments of vegetation composition, environmental setting, dynamics, threats, and characteristic species assemblages.

IVC hierarchy: The International Vegetation Classification hierarchy is sourced from the USNVC v3.0 Catalog, providing the full classification from Biome through Association levels.

Component associations: Plant community associations listed as components of each NatureServe Ecological System. Association data from the NatureServe Explorer API.

State ranks: Conservation status ranks assigned by NatureServe member programs in each state where the ecosystem occurs.