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CEGL001535 Artemisia tridentata ssp. wyomingensis / Pseudoroegneria spicata Shrub Grassland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Wyoming Big Sagebrush / Bluebunch Wheatgrass Shrub Grassland

Colloquial Name: Big Sagebrush / Bluebunch Wheatgrass Shrub Prairie

Hierarchy Level:  Association

Type Concept: This bunchgrass vegetation type with an open Wyoming big sagebrush shrub layer occurs in Montana, Wyoming, Colorado, Idaho, Washington, Oregon (apparently), Nevada, and British Columbia, Canada. It probably also occurs in western North Dakota and Utah, and it may occur in South Dakota. Stands occur on moderate to steep slopes at low to mid elevations, and on a variety of soils. Throughout the range of this association, the vegetation consists of an open to moderately dense shrub layer (about 10-25% canopy cover) dominated by Artemisia tridentata ssp. wyomingensis, and a herbaceous layer dominated by Pseudoroegneria spicata with lesser amounts of Poa secunda (sometimes a codominant grass). From the Great Plains westward to eastern Idaho and south to Colorado, the sagebrush seldom exceeds 0.5 m in height, but in western Idaho and Washington, the shrubs typically are 1 m tall. Other shrubs (especially Chrysothamnus sp.) and herbaceous species (especially Hesperostipa comata) usually are present. Festuca idahoensis is absent or present in small amounts. The stands in the eastern half of the geographic range often contain small amounts of Gutierrezia sarothrae, Artemisia frigida, Sphaeralcea coccinea, Phlox hoodii, Koeleria macrantha, and Opuntia polyacantha. Less constant species are Bouteloua spp. (especially Bouteloua gracilis), Carex filifolia, and Pascopyrum smithii. Missing from these stands is Achnatherum thurberianum. In the western half of the geographic range, the vegetation generally lacks the associated species listed above and often contains Antennaria dimorpha and Achnatherum thurberianum. In addition, the stands in Washington often contain large amounts of crustose lichens as ground cover.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Vegetation types that fit this association have been described from the Great Plains of western North Dakota, eastern Montana, and northeastern Wyoming on the east to southern interior British Columbia on the west, and as far south as northern Nevada and central Colorado. Based on differences in species composition, this association might be split into two associations or subassociations. The occurrences from the Great Plains west as far as northwestern Colorado, western Wyoming, and western Montana apparently belong to one association characterized by the presence of Bouteloua spp., Carex filifolia, Koeleria macrantha, Gutierrezia sarothrae, Artemisia frigida, and Opuntia polyacantha, and by the absence of Achnatherum thurberianum. Occurrences from southern Idaho, northern Nevada, eastern Oregon, eastern Washington, and British Columbia might belong to a different type characterized by the presence of Achnatherum thurberianum and by the absence of the other species listed above. The division between these two associations probably would be made in Idaho. ~Artemisia tridentata ssp. wyomingensis / Pseudoroegneria spicata Shrub Grassland (CEGL001535)$$ has a thicker sagebrush layer (generally >25% canopy cover) and less relative cover of herbaceous species. ~Artemisia tridentata ssp. wyomingensis / Poa secunda Shrubland (CEGL001049)$$ has an undergrowth dominated by Poa secunda and containing little Pseudoroegneria spicata. ~Artemisia tridentata (ssp. tridentata, ssp. xericensis) / Pseudoroegneria spicata Shrub Grassland (CEGL001018)$$ and ~Artemisia tridentata ssp. vaseyana / Pseudoroegneria spicata Shrubland (CEGL001030)$$ differ in having shrub layers dominated by those subspecies of big sagebrush.

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

Floristics: Throughout the range of this association, the vegetation consists of an open to moderately dense shrub layer (about 10-25% canopy cover) dominated by Artemisia tridentata ssp. wyomingensis, and a herbaceous layer dominated by Pseudoroegneria spicata with lesser amounts of Poa secunda (sometimes a codominant grass). Other shrubs (especially Chrysothamnus sp.) and herbaceous species (especially Hesperostipa comata (= Stipa comata)) usually are present. Festuca idahoensis is absent or present in small amounts. The stands in the eastern half of the geographic range often contain small amounts of Gutierrezia sarothrae, Artemisia frigida, Sphaeralcea coccinea, Phlox hoodii, Koeleria macrantha, and Opuntia polyacantha. Less constant species are Bouteloua spp. (especially Bouteloua gracilis) Carex filifolia, and Pascopyrum smithii (Fisser 1964, Mueggler and Stewart 1980, Tweit and Houston 1980, Baker and Kennedy 1985, Knight et al. 1987, Tiedemann et al. 1987, Hansen and Hoffman 1988, DeVelice and Lesica 1993, Cooper et al. 1995, Thilenius et al. 1995). Missing from these stands is Achnatherum thurberianum (= Stipa thurberiana). In the western half of the geographic range, the vegetation generally lacks the associated species listed above (although Tisdale (1947) reports Artemisia frigida in British Columbia) and often contains Antennaria dimorpha and Achnatherum thurberianum (Tisdale 1947, Blackburn 1967, Blackburn et al. 1968b, McLean 1970, Hironaka et al. 1983, Daubenmire 1988). In addition, the stands in Washington often contain large amounts of crustose lichens as ground cover. Descriptions and photographs of stands show that shrub height also varies across the range of this type. From the Great Plains westward to eastern Idaho and south to Colorado, the sagebrush seldom exceeds 0.5 m in height, but in western Idaho and Washington, the shrubs typically are 1 m tall.

Dynamics:  Heavy grazing generally decreases the amount of Pseudoroegneria spicata and Stipa spp. in the vegetation and increases the cover of Artemisia tridentata ssp. wyomingensis (and other shrubs), Poa secunda, Bouteloua gracilis, Bromus tectorum, Artemisia frigida, Gutierrezia sarothrae, Opuntia polyacantha, and other perennial and annual forbs, and removes the ground cover of cryptograms. Abusive grazing converts the vegetation to an Artemisia tridentata ssp. wyomingensis shrub layer with an undergrowth of Poa secunda, Bromus tectorum, and other grazing-resistant species. In Washington, fire and grazing together convert this type to a low grassland of Poa secunda and Bromus tectorum. In Idaho, stands of this association are valuable spring and fall livestock range and (especially in eastern Idaho) winter range for big game animals and sage grouse; management should strive for a good coverage of Pseudoroegneria spicata and an open shrub layer (Hironaka et al. 1983). This type is also important spring and fall cattle range in southwestern Montana, but the low coverage of forbs makes it less valuable for sheep (Mueggler and Stewart 1980).
Environmental Description:  On the Great Plains of eastern Montana and Wyoming (Hansen and Hoffman 1988, Thilenius et al. 1995), stands of this association occur on moderately steep to steep (16-45%) slopes and on gentle footslopes with various aspects, at 1340 to 1525 m (4400-5000 feet) elevation. Soils are loams, sandy loams, and sandy clay loams, often with coarse fragments in the upper horizons. Stands on the Wyoming plains often are on slopes of sandstone or porcelanite buttes (Thilenius et al. 1995). In the basins and foothills of south-central Montana (DeVelice and Lesica 1993) and north-central and central Wyoming (Fisser 1964, Tweit and Houston 1980, Knight et al. 1987), this association occupies mainly gentle to moderately steep (<35%) slopes at 1220 to 1830 m (4000-6000 feet) elevation. Soils are moderately deep, usually loamy (although one stand has been described from a clay soil), may have a considerable volume of coarse fragments, and have low electrical conductivity. In central and northwestern Colorado, stands of this association occupy gentle to steep slopes (to 65%) on a variety of landforms at elevations from about 2130 to 2500 m (7000-8200 feet). Soils are derived from a variety of parent materials and often are gravelly. In southwestern Montana (Mueggler and Stewart 1980, Cooper et al. 1995), stands grow at elevations from 1220 to 2290 m (4000-7500 feet), on slopes up to 54% with various exposures. Soils are shallow to moderately deep and derived from a variety of parent materials. In eastern Washington (Daubenmire 1988), this association occupies silt loam and sandy loam soils on gentle to moderately steep (8-38%) slopes with a variety of aspects, up to about 820 m (2700 feet) elevation. In British Columbia, this type grows on relatively warm, dry sites (Tisdale 1947), generally from 400 to 600 m (1300-1970 feet) elevation with stands on steep, south-facing slopes occurring as high as 900 m (2950 feet) (McLean 1970). Soils are loams, silt loams, and sandy loams.
Geographic Range: This association is known from Montana, Wyoming, Colorado, Idaho, Washington, Oregon (apparently), Nevada, and British Columbia, Canada. It probably also occurs in western North Dakota and Utah, and it may occur in South Dakota. This association is known to occur on the Thunder Basin National Grassland and on the Custer National Forest, Ashland District. It may also occur on the Sioux District and the Grand River Districts of the Custer National Forest.

Nations: CA?,US

States/Provinces:  AZ?, BC?, CA, CO, ID, MT, NM?, NV, OR, SD, UT?, WA, WY


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G4

Greasons: No Data Available
Type Name Database Code Classification Code
Class 3 Desert & Semi-Desert Class C03 3
Subclass 3.B Cool Semi-Desert Scrub & Grassland Subclass S11 3.B
Formation 3.B.1 Cool Semi-Desert Scrub & Grassland Formation F033 3.B.1
Division 3.B.1.Ne Western North American Cool Semi-Desert Scrub & Grassland Division D040 3.B.1.Ne
Macrogroup 3.B.1.Ne.3 Big Sagebrush - Threetip Sagebrush - Antelope Bitterbrush Steppe & Shrubland Macrogroup M169 3.B.1.Ne.3
Group 3.B.1.Ne.3.b Basin Big Sagebrush - Threetip Sagebrush - Antelope Bitterbrush Big Sagebrush Steppe & Shrubland Group G302 3.B.1.Ne.3.b
Alliance A3182 Wyoming Big Sagebrush Mesic Steppe & Shrubland Alliance A3182 3.B.1.Ne.3.b
Association CEGL001535 Wyoming Big Sagebrush / Bluebunch Wheatgrass Shrub Grassland CEGL001535 3.B.1.Ne.3.b
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Artemisia tridentata / Agropyron spicatum Community (Blackburn et al. 1968b)
= Artemisia tridentata / Agropyron spicatum Community (Blackburn 1967)
< Artemisia tridentata / Agropyron spicatum Habitat Type (Eckert 1957)
< Artemisia tridentata / Agropyron spicatum Habitat Type (Mueggler and Stewart 1980)
= Artemisia tridentata / Agropyron spicatum Habitat Type (Hansen and Hoffman 1988)
= Artemisia tridentata / Agropyron spicatum Habitat Type (Hess 1981)
= Artemisia tridentata / Agropyron spicatum Plant Community (DeVelice and Lesica 1993)
= Artemisia tridentata / Agropyron spicatum Vegetation Type (Thilenius et al. 1995)
< Artemisia tridentata / Roegneria spicata Plant Association (Johnston 1987)
= Artemisia tridentata ssp. wyomingensis / Agropyron spicatum Association (Baker and Kennedy 1985)
= Artemisia tridentata ssp. wyomingensis / Agropyron spicatum Community (Jones 1992b)
= Artemisia tridentata ssp. wyomingensis / Agropyron spicatum Community Type (Cooper et al. 1995)
= Artemisia tridentata ssp. wyomingensis / Agropyron spicatum Habitat Type (Tweit and Houston 1980)
= Artemisia tridentata ssp. wyomingensis / Agropyron spicatum Habitat Type (McLean 1970)
= Artemisia tridentata ssp. wyomingensis / Pseudoroegneria spicata (Jones and Ogle 2000)
= Artemisia tridentata ssp. wyomingensis / Pseudoroegneria spicata Shrub Herbaceous Vegetation (Faber-Langendoen 2001)
= Artemisia tridentata wyomingensis / Agropyron spicatum Habitat Type (Tiedemann et al. 1987)
= Artemisia wyomingensis / Agropyron spicatum Habitat Type (Hironaka et al. 1983)
Concept Author(s): Western Ecology Group

Author of Description: Western Ecology Group

Acknowledgements: No Data Available

Version Date: 11-26-97
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