Rocky Mountain Alpine Rocky Terrain

EVT 7143Rocky Mountain Alpine Fell-Field
CES306.811GNRHerbGrassland
Summary
This ecological system is found discontinuously at alpine elevations throughout the Rocky Mountains, west into the mountainous areas of the Great Basin, and north into the Canadian Rockies. Small areas are represented in the west side of the Okanagan Ecoregion in the eastern Cascades. 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. Most fell-field plants are cushioned or matted, frequently succulent, flat to the ground in rosettes and often densely haired and thickly cutinized. Plant cover is 15-50%, while exposed rocks make up the rest. Fell-fields are usually within or adjacent to alpine tundra dry meadows. Common species include Arenaria capillaris, Geum rossii, Kobresia myosuroides, Minuartia obtusiloba, Myosotis asiatica, Paronychia pulvinata, Phlox pulvinata, Sibbaldia procumbens, Silene acaulis, Trifolium dasyphyllum, and Trifolium parryi.
Source: NatureServe Explorer
Distribution
This system is found discontinuously at alpine elevations throughout the Rocky Mountains, west into the mountainous areas of the Great Basin. Outlier sites occur in the northeastern Cascades and on Mount Rainier in Washington.
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.

Herb (field)

Bistorta bistortoides, Carex myosuroides, Eremogone capillaris, Festuca brachyphylla ssp. coloradensis, Geum rossii, Ivesia gordonii, Minuartia obtusiloba, Myosotis asiatica, Paronychia pulvinata, Phleum alpinum, Phlox pulvinata, Poa secunda, Potentilla diversifolia, Sedum lanceolatum, Sibbaldia procumbens, Silene acaulis, Trifolium dasyphyllum, Trifolium parryi, Trisetum spicatum
Source: NatureServe Ecological System assessment
Ecologically Associated Animals (3)

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.

Birds (1)

Common NameScientific NameG-Rank
White-tailed PtarmiganLagopus leucuraG5

Amphibians (1)

Common NameScientific NameG-Rank
Sacramento Mountains SalamanderAneides hardiiG3

Other (1)

Common NameScientific NameG-Rank
Greater Short-horned LizardPhrynosoma hernandesiG5
Source: NatureServe Ecological System assessment
At-Risk Species Associated with this Ecosystem (2)

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 NameScientific NameG-RankESA Status
Sacramento Mountains SalamanderAneides hardiiG3--
Rocky Mountain NailwortParonychia pulvinataG3?--
Source: NatureServe Ecological System assessment
Component Associations (16)

Plant community associations that occur within this ecological system. Associations are the finest level of the U.S. National Vegetation Classification (USNVC) and describe specific, repeating assemblages of plant species. Each association represents a distinct community type that may be found where this ecosystem occurs.

NameG-Rank
Arenaria capillaris / Polytrichum piliferum Alpine SnowbedG2 NatureServe
Carex albonigra - Myosotis asiatica Alpine Fell-fieldG2 NatureServe
Carex paysonis - Sibbaldia procumbens Alpine SnowbedG3 NatureServe
Dasiphora fruticosa / Artemisia michauxiana Alpine Shrub MeadowG3 NatureServe
Geum rossii - Minuartia obtusiloba Alpine Fell-fieldG3 NatureServe
Kobresia myosuroides - Euphrasia disjuncta Alpine TurfG2 NatureServe
Minuartia obtusiloba Alpine Fell-fieldG4 NatureServe
Paronychia pulvinata - Silene acaulis Alpine Fell-fieldG5 NatureServe
Phlox pulvinata Alpine Fell-fieldG4 NatureServe
Phlox pulvinata - Trifolium dasyphyllum Alpine Fell-fieldG2 NatureServe
Potentilla sierrae-blancae Alpine Fell-fieldG1 NatureServe
Rubus idaeus Shrubby ScreeGU NatureServe
Sibbaldia procumbens - Polygonum bistortoides Wet MeadowG3 NatureServe
Silene acaulis Alpine Fell-fieldG5 NatureServe
Trifolium dasyphyllum Alpine Fell-fieldG4 NatureServe
Trifolium parryi Alpine SnowbedGU NatureServe
State Conservation Ranks (9)

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.

StateS-Rank
COSNR
IDSNR
MTSNR
NMSNR
NVSNR
ORSNR
UTSNR
WASNR
WYSNR
Roadless Areas (12)

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.

Montana (3)

AreaForestCoverageHectares
Storm LakeBeaverhead-Deerlodge National Forest1.2%44.91
East PioneerBeaverhead-Deerlodge National Forest0.5%288.18
West Big HoleBeaverhead-Deerlodge National Forest0.2%132.3

Utah (1)

AreaForestCoverageHectares
0419020Ashley National Forest0.1%201.24

Wyoming (8)

AreaForestCoverageHectares
Beartooth Proposed WildernessShoshone National Forest2.2%151.38
Franc's PeakShoshone National Forest2.0%541.53
Headwaters Sunlight CreekShoshone National Forest1.8%44.73
South ForkShoshone National Forest0.9%228.24
Wood RiverShoshone National Forest0.8%162.09
Dunoir Special Management UnitShoshone National Forest0.6%68.22
South Wyoming RangeBridger-Teton National Forest0.3%94.23
South Beartooth HighwayShoshone National Forest0.3%109.35
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.