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CEGL001579 Pascopyrum smithii - Bouteloua gracilis - Carex filifolia Grassland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Western Wheatgrass - Blue Grama - Threadleaf Sedge Grassland

Colloquial Name: Western Wheatgrass - Blue Grama - Threadleaf Sedge Prairie

Hierarchy Level:  Association

Type Concept: This western wheatgrass prairie community occurs throughout much of the northwestern Great Plains of the United States and Canada, on flat or gently sloping terrain. Many stands are on floodplains or gentle valley slopes. Some are on uplands. The soils are clay loam, silt loam, or loam and usually deep and fertile. This community is dominated by medium and short graminoids. The midgrass stratum is dominated by Pascopyrum smithii or Elymus lanceolatus. Common associates include Koeleria macrantha, Hesperostipa comata, and Nassella viridula. Hesperostipa comata is more common on the upper slopes and drier upland sites with sandier soils, whereas Nassella viridula is more common on the lower slopes and floodplains with finer-textured soils. The most common short graminoid is Bouteloua gracilis. Other common graminoids include Carex filifolia, Carex inops ssp. heliophila, Carex duriuscula, and Carex pensylvanica. Forbs do not contribute much of the canopy cover but they are scattered throughout this community. Typical forbs are Tragopogon dubius, Gaura coccinea, Hedeoma hispida, Phlox hoodii and Sphaeralcea coccinea.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Almost any combination of Pascopyrum smithii, Bouteloua gracilis, Carex filifolia, and Hesperostipa comata can be found in the northern and northwestern Great Plains, and the relative amounts of these species apparently depend at least in part on soil texture and grazing history. Moreover, drought or wet weather can cause the relative amounts of these species in one stand to change markedly in a few years (Ellison and Woolfolk 1937, Weaver and Albertson 1956). Consequently, differentiating between plant associations based solely on the relative amounts of these species is extremely difficult. This Pascopyrum smithii - Bouteloua gracilis - Carex filifolia association is found on soils in textural classes finer than loam in which Pascopyrum smithii and/or Elymus lanceolatus (which is similar morphologically and ecologically) contribute at least as much cover as does Hesperostipa comata. Bouteloua gracilis, Elymus lanceolatus and Carex filifolia may be patchily distributed, so areas of several acres should be examined to determine whether the vegetation belongs to this association. This association shares major graminoid species with ~Hesperostipa comata - Bouteloua gracilis - Carex filifolia Grassland (CEGL002037)$$ but in the latter association, Hesperostipa comata contributes more cover than do Pascopyrum smithii or Elymus lanceolatus, and the latter association grows on soils of loam or coarser textural classes. In Nebraska, this type occurs north of Pine Ridge and is common in the Oglala National Grasslands.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: This community is dominated by medium and short graminoids. Total vegetation cover is usually high (Hanson and Dahl 1956, Hansen et al. 1984). Pascopyrum smithii or Elymus lanceolatus or both (the two species are similar both morphologically and ecologically) and Bouteloua gracilis usually contribute the most cover; however, Bouteloua gracilis cover may vary from codominant to locally absent. Carex filifolia, Carex duriuscula (= Carex eleocharis), and Carex pensylvanica are often secondary species, but they also vary from moderate cover to locally absent. Hesperostipa comata (= Stipa comata) usually is present as a secondary species, but it often codominates on sandy loam soils. In Alberta and Saskatchewan, Hesperostipa curtiseta (= Stipa spartea var. curtiseta) may be as common as Hesperostipa comata. Koeleria macrantha is present in most stands and may contribute substantial cover. The forbs most likely to be found in this association are Phlox hoodii, Sphaeralcea coccinea, Polygonum ramosissimum, Plantago patagonica, Opuntia polyacantha, Artemisia frigida, Antennaria microphylla, and Hedeoma hispida. In southeastern Montana, western North Dakota, and northeastern Wyoming, stands of this association often contain Artemisia tridentata ssp. wyomingensis. Exotic brome grasses, especially Bromus racemosus (= Bromus commutatus) and Bromus tectorum, are present in many stands of this association and they commonly contribute substantial cover (Hanson and Dahl 1956, Coupland 1961, Hansen et al. 1984, Hansen and Hoffman 1988).

Dynamics:  In the past, fire likely occurred commonly in this type. The coverage of Pascopyrum smithii varies more with use than geographic range. Bouteloua gracilis and Bouteloua dactyloides have been observed to increase with grazing as Pascopyrum smithii decreases.
Environmental Description:  This community is found on flat or gently sloping terrain. Many stands are on floodplains or gentle valley slopes, others are on uplands. Surface layers of soils are usually clay loams, although stands of this type may also be found on loams, silt loams, silty clays and clays (Hanson and Whitman 1938, Hansen and Hoffman 1988). In Alberta and Saskatchewan this association grows on solonetzic soils (with an eluvial horizon above a dense clay horizon high in sodium salts) developed on thin glacial till over Cretaceous shale (Coupland 1961). This community does not appear to be found in mountain valleys (Hanson and Dahl 1956, Jones 1992b).
Geographic Range: This western wheatgrass prairie community occurs throughout much of the northwestern Great Plains of the United States and Canada on flat or gently sloping terrain, ranging from Alberta and Saskatchewan in Canada south to Nebraska (but north of Pine Ridge).

Nations: CA,US

States/Provinces:  AB, CO, MT, ND, NE, SD, SK, WY


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G4

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.Nb Central North American Grassland & Shrubland Division D023 2.B.2.Nb
Macrogroup 2.B.2.Nb.2 Needle-and-Thread - Western Wheatgrass - Plains Rough Fescue Grassland Macrogroup M051 2.B.2.Nb.2
Group 2.B.2.Nb.2.c Western Wheatgrass - Needle-and-Thread - Little Bluestem Mixedgrass Prairie Group G141 2.B.2.Nb.2.c
Alliance A4031 Western Wheatgrass - Green Needlegrass Northwestern Great Plains Grassland Alliance A4031 2.B.2.Nb.2.c
Association CEGL001579 Western Wheatgrass - Blue Grama - Threadleaf Sedge Grassland CEGL001579 2.B.2.Nb.2.c
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Agropyron smithii / Bouteloua gracilis Community (Jones 1992b)
> Agropyron smithii / Carex filifolia Community (Jones 1992b)
= Agropyron smithii / Carex filifolia Habitat Type (Hansen and Hoffman 1988)
= Agropyron smithii / Carex filifolia Habitat Type (Hansen et al. 1984)
= Bromus tectorum - Agropyron smithii - Bouteloua gracilis Association (Hanson and Dahl 1956)
< Elytrigia smithii / Bouteloua gracilis Plant Association (Johnston 1987)
= Elytrigia smithii / Carex filifolia Plant Association (Johnston 1987)
= Pascopyrum smithii - Bouteloua gracilis - Carex filifolia Herbaceous Vegetation (Butler et al. 2002)
= Pascopyrum smithii - Bouteloua gracilis - Carex filifolia Herbaceous Vegetation (Faber-Langendoen 2001)
= Western Wheatgrass - Grama - Sedge Type (Hanson and Whitman 1938) [Types previously separated as Pascopyrum smithii / Bouteloua gracilis or Pascopyrum smithii / Carex filifolia in the literature are now lumped together as ~Pascopyrum smithii / Bouteloua gracilis - Carex filifolia Grassland (CEGL001579)$$.]
Concept Author(s): H.C. Hanson and W. Whitman (1938)

Author of Description: H.C. Hanson, W. Whitman, J. Drake and D. Faber-Langendoen

Acknowledgements: No Data Available

Version Date: 12-20-95
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