Print Report

A3965 Festuca idahoensis - Carex scirpoidea - Danthonia intermedia Central Rocky Mountain Subalpine Dry Grassland Alliance

Type Concept Sentence: This alliance is characterized by a sparse to moderately dense herbaceous layer dominated by the diagnostic perennial bunchgrass Festuca idahoensis with Carex obtusata, Carex scirpoidea, Danthonia intermedia, Eriogonum caespitosum, Leucopoa kingii, or Potentilla diversifolia codominating. It is described from dry and often rocky subalpine and lower alpine slopes exposed to desiccating winds in the central Rocky Mountains of central and southern Idaho, western and south-central Montana, and northwestern Wyoming.

Common (Translated Scientific) Name: Idaho Fescue - Northern Single-spike Sedge - Timber Oatgrass Central Rocky Mountain Subalpine Dry Grassland Alliance

Colloquial Name: Central Rocky Mountain Subalpine Dry Idaho Fescue Grassland

Hierarchy Level:  Alliance

Type Concept: The vegetation of this grassland alliance is characterized by a sparse to moderately dense herbaceous layer dominated by the diagnostic perennial bunchgrass Festuca idahoensis with Carex obtusata, Carex scirpoidea, Danthonia intermedia, Eriogonum caespitosum, Leucopoa kingii, or Potentilla diversifolia codominating. In more exposed settings, Festuca idahoensis sometimes relinquishes dominance to Festuca campestris. Many other species are reported to occur, the most abundant being Agoseris glauca, Antennaria corymbosa, Carex filifolia, Carex praticola, Deschampsia cespitosa, Erigeron linearis, Eriogonum ovalifolium, Galium boreale, Geum triflorum, Ivesia gordonii, Lupinus argenteus, Packera cana, Phleum alpinum, Phlox hoodii, Potentilla diversifolia, Pseudoroegneria spicata, and Stenotus acaulis. Cushion plants are common on more exposed sites. Scattered low shrubs (Artemisia frigida or Artemisia tridentata ssp. vaseyana) may be present. This alliance is described from subalpine and lower alpine slopes in the central Rocky Mountains of central and southern Idaho, western and south-central Montana, and northwestern Wyoming. Stands range from 1980-2655 m (6500-8700 feet) elevation. Sites are dry and often rocky, and exposed to desiccating winds. This dry meadow vegetation occurs on a variety of soil types on upland slopes and broad ridgetops. The composition of the vegetation depends in part on soil type; graminoid cover reaches its maximum in stands on coarse-textured soils derived from granitic bedrock, and forb cover reaches its maximum in stands on finer-textured soils derived from sedimentary bedrock.

Diagnostic Characteristics: This alliance is characterized by a sparse to moderately dense herbaceous layer dominated by the diagnostic perennial bunchgrass Festuca idahoensis with other diagnostic species codominating, including Carex obtusata, Carex scirpoidea, Danthonia intermedia, Eriogonum caespitosum, Leucopoa kingii, or Potentilla diversifolia. In more exposed settings, Festuca idahoensis sometimes relinquishes dominance to Festuca campestris. Associated species include Agoseris glauca, Antennaria corymbosa, Artemisia frigida, Artemisia tridentata ssp. vaseyana, Carex filifolia, Carex praticola, Deschampsia cespitosa, Erigeron linearis, Eriogonum ovalifolium, Galium boreale, Geum triflorum, Ivesia gordonii, Lupinus argenteus, Packera cana, Phleum alpinum, Phlox hoodii, Potentilla diversifolia, Pseudoroegneria spicata, and Stenotus acaulis.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: There are similarities between ~Festuca idahoensis - Carex scirpoidea Grassland (CEGL001899)$$ and ~Festuca idahoensis - (Festuca campestris) / Potentilla diversifolia Grassland (CEGL001623)$$ that may warrant classifying the two types into one association. In addition, Hurd (1961) reported a Festuca idahoensis / Carex obtusata grassland for the Bighorn Mountains in Wyoming, between 2135 and 2560 m elevation. The Pryor Mountains in Montana are a northwestern extension of the Bighorns. Carex obtusata and Carex scirpoidea are closely related and could possibly be confused. These two grasslands may actually be the same (Reid et al. 1994). For further confusion, ~Festuca idahoensis - Carex scirpoidea Grassland (CEGL001899)$$ was based on a single stand in central Montana that had 40% cover of Carex scirpoidea and 10% cover of Festuca idahoensis (Mueggler and Stewart 1980).

~Festuca idahoensis Grassland (CEGL001897)$$ in this alliance is reported from alpine habitats in Colorado, Oregon and possibly California, but is poorly defined. Festuca idahoensis-dominated stands in California need further investigation and association-level description, especially any alpine types that may be included in this alliance (Sawyer and Keeler-Wolf 1995). Some of the associations included in this alliance occur largely in the alpine and may be considered alpine turf.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation in this alliance is characterized by moderate to dense cover of graminoids that is dominated by perennial bunch grasses less than 0.5 m tall. There is also a sparse to moderate cover of perennial forbs (<0.5 m tall). Annual forbs (and grasses) may be seasonally present but have very low cover.

Floristics: The vegetation is characterized by a sparse to moderately dense herbaceous layer dominated by the diagnostic perennial bunchgrass Festuca idahoensis with Carex obtusata, Carex scirpoidea, Danthonia intermedia, Eriogonum caespitosum, Leucopoa kingii (= Festuca kingii), or Potentilla diversifolia codominating. In more exposed settings, Festuca idahoensis sometimes relinquishes dominance to Festuca campestris. Many other species are reported to occur, the most abundant being Agoseris glauca, Antennaria corymbosa, Arenaria capillaris, Campanula rotundifolia, Carex filifolia, Carex praticola, Deschampsia cespitosa, Erigeron linearis, Eriogonum ovalifolium, Eriophyllum lanatum, Galium boreale, Geum triflorum, Ivesia gordonii, Lathyrus nevadensis, Lupinus arcticus ssp. subalpinus, Lupinus argenteus, Packera cana (= Senecio canus), Phleum alpinum, Phlox hoodii, Polygonum bistortoides, Potentilla diversifolia, Pseudoroegneria spicata, and Stenotus acaulis (= Haplopappus acaulis). Cushion plants are common on more exposed sites. Scattered low shrubs (Artemisia frigida or Artemisia tridentata ssp. vaseyana) may be present. Occasional trees may be scattered in these stands such as individuals of Abies lasiocarpa.

Dynamics:  These stands occur in alpine and in upper subalpine parks and meadows that have been created by fire or where other disturbance or edaphic factors limit tree growth. Environmental factors important to alpine vegetation include soil moisture, amount and length of snow cover, aspect, and exposure to wind. These stands are on warmer/drier southern and western exposures where snow clears relatively early (mid-June) and wind exposure is less than the cushion plant vegetation types (Kuramoto and Bliss 1970).
Environmental Description:  This alliance is described from subalpine and lower alpine slopes in the central Rocky Mountains of central and southern Idaho, western and south-central Montana, and northwestern Wyoming. Stands range from 1980-2655 m (6500-8700 feet) elevation. Sites are dry and often rocky, and exposed to desiccating winds. This dry meadow vegetation occurs on a variety of soil types on gentle to moderately steep upland slopes and broad ridgetops. The composition of the vegetation depends in part on soil type; graminoid cover reaches its maximum in stands on coarse-textured soils derived from granitic bedrock, and forb cover reaches its maximum in stands on finer-textured soils derived from sedimentary bedrock. The alliance appears to be restricted to high-elevation sites of intermediate productivity where combined factors of duration of snow cover, exposure to winter desiccation, and growing-season soil-moisture availability allow its occurrence.
Geographic Range: This alliance is described from subalpine and lower alpine slopes of the Pioneer, White Knob, and Beaverhead mountains of central Idaho and western Montana, the Pryor Mountains in south-central Montana, Blackpine Mountains of southern Idaho, the Bighorn Mountain sand central plateau of Yellowstone National Park and adjacent Grand Teton National Park in northern Wyoming.

Nations: CA?,US

States/Provinces:  AB?, CA?, CO, ID, MT, OR, WA, WY


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: GNR

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.B Temperate & Boreal Grassland & Shrubland Subclass S18 2.B
Formation 2.B.2 Temperate Grassland & Shrubland Formation F012 2.B.2
Division 2.B.2.Nf Western North American Grassland & Shrubland Division D022 2.B.2.Nf
Macrogroup 2.B.2.Nf.2 Saskatoon Serviceberry / Idaho Fescue - Bluebunch Wheatgrass Grassland & Shrubland Macrogroup M048 2.B.2.Nf.2
Group 2.B.2.Nf.2.a Downy Ryegrass - Idaho Fescue - Spike Fescue Grassland Group G267 2.B.2.Nf.2.a
Alliance A3965 Idaho Fescue - Northern Single-spike Sedge - Timber Oatgrass Central Rocky Mountain Subalpine Dry Grassland Alliance A3965 2.B.2.Nf.2.a
Association CEGL001611 Idaho Fescue - Obtuse Sedge Grassland CEGL001611 2.B.2.Nf.2.a
Association CEGL001612 Idaho Fescue - Timber Oatgrass Grassland CEGL001612 2.B.2.Nf.2.a
Association CEGL001615 Idaho Fescue - Matted Buckwheat Grassland CEGL001615 2.B.2.Nf.2.a
Association CEGL001623 Idaho Fescue - (Rough Fescue) / Varileaf Cinquefoil Grassland CEGL001623 2.B.2.Nf.2.a
Association CEGL001897 Idaho Fescue Grassland CEGL001897 2.B.2.Nf.2.a
Association CEGL001899 Idaho Fescue - Northern Single-spike Sedge Grassland CEGL001899 2.B.2.Nf.2.a
Association CEGL001901 Idaho Fescue - Spike Fescue Grassland CEGL001901 2.B.2.Nf.2.a
Concept Lineage: This new alliance is composed of associations from Old Alliance V.A.5.N.d. Festuca idahoensis Herbaceous Alliance (A.1251) and Old Alliance V.A.5.N.h. Festuca idahoensis Alpine Herbaceous Alliance (A.1313).

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: < Festuca idahoensis Series (Johnston 1987) [includes thirteen Festuca idahoensis-dominated plant associations.]
< Festuca idahoensis Series (Tisdale 1986)
>< Subalpine and Alpine Grasslands (Chappell et al. 1997)
Concept Author(s): K.A. Schulz, in Faber-Langendoen et al. (2013)

Author of Description: K.A. Schulz

Acknowledgements: S.V. Cooper contributed to Classification Comments, and M.S. Reid wrote the group description.

Version Date: 03-14-14
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