Print Report

A3988 Festuca idahoensis - Pseudoroegneria spicata - Pascopyrum smithii Mesic Grassland Alliance

Type Concept Sentence: This mesic grassland association is characterized by an open to moderately dense herbaceous layer dominated by diagnostic perennial grass Festuca idahoensis or Pseudoroegneria spicata with mesic-site indicator species Bromus marginatus, Elymus lanceolatus, Koeleria macrantha, or Pascopyrum smithii and is found primarily east of the Continental Divide in foothills in northwestern Montana.

Common (Translated Scientific) Name: Idaho Fescue - Bluebunch Wheatgrass - Western Wheatgrass Mesic Grassland Alliance

Colloquial Name: Idaho Fescue - Wheatgrass Mesic Grassland

Hierarchy Level:  Alliance

Type Concept: This alliance is composed of mesic to subhygric, diverse grasslands characterized by a lush meadow dominated by diagnostic perennial grasses Festuca idahoensis and/or Pseudoroegneria spicata. Mesic indicator species Bromus marginatus, Elymus lanceolatus, Koeleria macrantha, or Pascopyrum smithii are present to codominant in the graminoid layer. The short shrubs Symphoricarpos albus, Rosa nutkana, or Rosa woodsii are frequently present and may form an open layer or scattered clumps, usually with less than a quarter of the bunchgrass cover. Artemisia frigida is common in eastern stands. Other grass associates include Poa cusickii and Poa secunda. The forb component has high species diversity and less cover than graminoids. Non-native grasses Bromus briziformis, Phleum pratense, and Poa palustris are important in some stands. The biological crust is very well-developed on undisturbed sites. This alliance found in the central Rocky Mountains from the Palouse region and Blue Mountains to the foothills east of the Continental Divide in northwestern and Montana and Alberta. Stands occur on gentle to steep slopes at 370 to 2015 m elevation from sites on the dissected basalt plateaus, canyon and mountain slopes of the lower Snake River drainage and on the eastern flanks of the Blue Mountains on relatively deep loessal soils that overlay basalt rock or colluvium. Stands range northeast to east of the Continental Divide on gentle slopes at elevations from 1200-1800 m, but may be found up to 2400 m on moderately deep, moderately well-drained, coarse-textured soils. Litter and small rock dominate the ground surface. Stands typically occur where moisture is available well into summer drought because of cool aspect or subsurface seepage.

Diagnostic Characteristics: This alliance is characterized by an open to moderately dense herbaceous layer dominated by diagnostic perennial grass Festuca idahoensis or Pseudoroegneria spicata. Mesic-site indicator species Bromus marginatus, Elymus lanceolatus, Koeleria macrantha, or Pascopyrum smithii are present to codominant. The short shrubs Symphoricarpos albus, Rosa nutkana, or Rosa woodsii are frequently present and may form an open shrub layer. Forbs have high diversity and typically low cover. Associated forb species include Achillea millefolium, Antennaria rosea, Aquilegia flavescens, Artemisia frigida, Balsamorhiza sagittata, Clarkia pulchella, Erigeron peregrinus, Fragaria virginiana, Gaillardia aristata, Galium boreale, Geranium viscosissimum, Hedysarum sulphurescens, Koeleria macrantha, Lithospermum ruderale, Lupinus sericeus, Phlox hoodii, Poa cusickii, Poa secunda, Thalictrum occidentale, and Zigadenus elegans.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: These three relatively mesic Festuca idahoensis- and Pseudoroegneria spicata-dominated associations are grouped into this central Rocky Mountain grassland alliance. More vegetation survey and classification work are needed to clarify the extent of its component associations. ~Bromus marginatus - Pseudoroegneria spicata Grassland (CEGL005861)$$ occurs in subalpine Alberta and may be better classified in ~Central Rocky Mountain Montane Grassland Group (G267)$$.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation in this alliance is characterized by a moderate to dense cover of graminoids that is dominated by perennial bunch grasses less than 1 m tall. There is also sparse to moderate cover of perennial forbs. Annual forbs and grasses are seasonally present and may be abundant. Occasional scattered deciduous shrubs and dwarf-shrubs may be present and sometimes form an open layer.

Floristics: Vegetation in this alliance is characterized by a lush meadow with a moderate to dense herbaceous layer dominated by diagnostic perennial grasses Festuca idahoensis and/or Pseudoroegneria spicata. Bromus marginatus, Elymus lanceolatus, Koeleria macrantha, or Pascopyrum smithii frequently codominate the graminoid layer on these sites and are indicative of more mesic environments. The short shrubs Symphoricarpos albus, Rosa nutkana, or Rosa woodsii are frequently present and may form an open layer or scattered clumps, usually with less than a quarter of the bunchgrass cover. Artemisia frigida is common in eastern stands. Other grass associates include Poa cusickii and Poa secunda (= Poa sandbergii). Non-native grasses Bromus briziformis, Phleum pratense, and Poa palustris are important in some stands. Graminoids are far more abundant than shrubs and forbs. Forbs species are often diverse, and are present to abundant. The most prominent forbs are Achillea millefolium, Anemone multifida, Antennaria rosea, Aquilegia flavescens, Arnica sororia, Balsamorhiza sagittata, Calochortus apiculatus, Castilleja hispida, Clarkia pulchella, Erigeron peregrinus, Eurybia conspicua (= Aster conspicuus), Fragaria virginiana, Frasera albicaulis, Gaillardia aristata, Galium boreale, Geranium viscosissimum, Hedysarum sulphurescens, Hieracium scouleri var. albertinum (= Hieracium albertinum), Lithospermum ruderale, Lomatium triternatum, Lupinus sericeus, Osmorhiza occidentalis, Phlox hoodii, Thalictrum occidentale, Triteleia grandiflora var. grandiflora (= Brodiaea douglasii), Valeriana dioica, and Zigadenus elegans. The biological crust is very well-developed on undisturbed sites. Grazing reduces the cover of the native perennial grasses. Reduction or elimination of grazing does not appear to restore the native perennial grasses. Other species invading grazed stands include Lagophylla ramosissima, Myosurus apetalus var. borealis (= Myosurus aristatus), Sanguisorba annua (= Sanguisorba occidentalis), and Veronica arvensis.

Dynamics:  Fire has variable effects on bunch grasses Pseudoroegneria spicata and Festuca idahoensis. Plants usually survive burning, and growth is often stimulated, except when fire occurs in the driest month when the crowns will burn because of low moisture in the vegetation, and the meristems are damaged (Johnson and Simon 1987). Grazing impacts are concentrated on the gentler slopes accessible to livestock. Pseudoroegneria spicata shows an inconsistent reaction to grazing, increasing on some grazed sites while decreasing on others. It seems to recover more quickly from overgrazing than Festuca campestris (Mueggler and Stewart 1980). It tolerates dormant-period grazing well, but is sensitive to defoliation during the growing season. Light spring use or fall grazing can help retain plant vigor. It is particularly sensitive to defoliation in late spring (Comer et al. 1999). The exotic species Bromus tectorum occurs in many stands of the alliance and contributes significant cover on sites disturbed by livestock.
Environmental Description:  This is a mesic to subhygric, diverse grassland found in the central Rocky Mountains from the Palouse region and Blue Mountains to the northeast in foothills on the east slope of the Continental Divide in northwestern and Montana and Alberta. Stands occur on gentle to steep, northwest- to northeast-facing slopes at 370 to 2015 m elevation from sites on the dissected basalt plateaus, biscuit-and-swale (mound) formations, and high- and low-elevation canyon and mountain slopes of the lower Snake River drainage and on the eastern flanks and in the rainshadow of the Blue Mountains on relatively deep loessal soils that overlay basalt rock or colluvium. (Daubenmire 1970). Stands range to east of the Continental Divide on gentle slopes at elevations from 1200-1800 m, but may be found up to 2400 m on moderately deep, moderately well-drained, coarse-textured soils developed on morainal or soils derived from sedimentary rock (Reid et al. 2004). Litter and small rock dominate the ground surface. Stands typically occur where moisture is available well into summer drought because of cool aspect or subsurface seepage.
Geographic Range: This mesic grassland alliance is found in the central Rocky Mountains from the Palouse region and Blue Mountains in eastern Oregon, southwestern Washington, and Idaho to the foothills east of the Continental Divide in northwestern and Montana and Alberta.

Nations: CA,US

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


Confidence Level: Moderate

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.c Rough Fescue - Idaho Fescue - Bluebunch Wheatgrass Central Rocky Mountain Foothill Grassland Group G273 2.B.2.Nf.2.c
Alliance A3988 Idaho Fescue - Bluebunch Wheatgrass - Western Wheatgrass Mesic Grassland Alliance A3988 2.B.2.Nf.2.c
Association CEGL001509 Idaho Fescue - Common Snowberry Grassland CEGL001509 2.B.2.Nf.2.c
Association CEGL001620 Idaho Fescue - Prairie Junegrass Grassland CEGL001620 2.B.2.Nf.2.c
Association CEGL001621 Idaho Fescue - Western Wheatgrass Grassland CEGL001621 2.B.2.Nf.2.c
Association CEGL001626 Nootka Rose - Idaho Fescue Grassland CEGL001626 2.B.2.Nf.2.c
Association CEGL005653 Western Wheatgrass Central Rocky Mountain Grassland CEGL005653 2.B.2.Nf.2.c
Association CEGL005654 Western Wheatgrass Southern Rocky Mountain Grassland CEGL005654 2.B.2.Nf.2.c
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.d. Pseudoroegneria spicata Herbaceous Alliance (A.1265).

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: >< Festuca idahoensis Series (Tisdale 1986)
> Idaho Fescue Series (Sawyer and Keeler-Wolf 1995)
Concept Author(s): K.A. Schulz, in Faber-Langendoen et al. (2013)

Author of Description: K.A. Schulz

Acknowledgements: No Data Available

Version Date: 03-14-14
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