Print Report

CEGL001578 Pascopyrum smithii - Bouteloua gracilis Grassland

Type Concept Sentence: This type is found in the southwestern Great Plains and into western New Mexico where Pascopyrum smithii and Bouteloua gracilis dominate in swales and valleys.

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

Colloquial Name: Western Wheatgrass - Blue Grama Mixedgrass Prairie

Hierarchy Level:  Association

Type Concept: This western wheatgrass - blue grama prairie of the southern Great Plains andthe western New Mexico mountains of the United States was once an extensive grassland. Stands occur along upland valley bottoms. It generally occurs on northerly or northeasterly aspects at elevations between 915 and 2440 m (3000-8000 feet). Slopes are typically gentle with fine-textured and well-developed soils that are predominantly from eroded Paleozoic sandstone and limestone. Ground cover is characterized by scattered bunchgrasses and patches of the rhizomatous grasses and litter with exposed soil and gravel in the intergrass spaces. Luxuriant cover that can be dominated by either Bouteloua gracilis or Pascopyrum smithii typifies this grassland. In Kansas, Bouteloua curtipendula and Bouteloua dactyloides may also be present In New Mexico, Atriplex canescens is the most frequently occurring and abundant shrub, with Ericameria nauseosa, Opuntia phaeacantha, and Gutierrezia sarothrae common associates, but overall cover seldom exceeds 2.5%. Graminoid diversity is usually low, with scattered grasses such as Elymus elymoides, Koeleria macrantha, and Muhlenbergia repens often present.. The shrub layer is very open and moderate in diversity and generally includes Atriplex canescens and Krascheninnikovia lanata (which both occur as phases and can become dominant in disturbed areas), as well as Cylindropuntia imbricata and Opuntia phaeacantha. Forb diversity and cover are generally low.

Diagnostic Characteristics: This association is characterized by stands dominated by Pascopyrum smithii and Bouteloua gracilis.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This one association (CEGL001578) of this alliance should be considered in relation to associations in ~Pascopyrum smithii - Nassella viridula Northwestern Great Plains Grassland Alliance (A4031)$$. The current description includes vegetation in New Mexico, which may be sufficiently distinct from Great Plains to warrant further review. The limits of this type in western Oklahoma needs review.

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

Floristics: This grassland contains dense cover that can be dominated by either Bouteloua gracilis or Pascopyrum smithii. Graminoid diversity is usually low, with scattered grasses such as Elymus elymoides, Koeleria macrantha, and Muhlenbergia repens often present. In Kansas, Bouteloua curtipendula and Bouteloua dactyloides (= Buchloe dactyloides) may also be present (Lauver et al. 1999). In the Texas panhandle, Buchloe dactyloides and Bouteloua curtipendula are common associates. Bouteloua spp disappear in wetter swales. The shrub layer is very open and moderate in diversity and generally includes Atriplex canescens and Krascheninnikovia lanata (which both occur as phases and can become dominant in disturbed areas), as well as Cylindropuntia imbricata (= Opuntia imbricata) and Opuntia phaeacantha. New Mexico stands contain a different set of associates. There, Juniperus monosperma or Pinus edulis communities usually surround this swale association. Atriplex canescens is the most frequently occurring and abundant shrub, with Ericameria nauseosa, Opuntia phaeacantha, and Gutierrezia sarothrae common associates, but overall cover seldom exceeds 2.5%. Forb diversity and cover are generally low. In New Mexico, forbs are common but variable; the most abundant are Artemisia campestris ssp. caudata, Engelmannia peristenia, Glandularia bipinnatifida, and Penstemon virgatus. Trees and shrubs are accidental or absent.

Dynamics:  Pascopyrum smithii is rhizomatous and is tolerant of moderate grazing. If severely over-grazed, Pascopyrum smithii will decline and may be replaced by less desirable warm season grasses and exotic species such as Poa pratensis.
Environmental Description:  Stands occur along upland valley bottoms or, in New Mexico, within montane swales, where it generally occurs on northerly or northeasterly aspects at elevations between 915 and 2500 m (3000-8000 feet). Slopes are typically gentle with fine-textured and well-developed soils that are predominantly from eroded Paleozoic sandstone and limestone. In Kansas, stands are common on nearly level uplands or shallow depressions in uplands. Soils are silty clay loam with an impermeable or slowly permeable claypan subsoil layer (Lauver et al. 1999). Ground cover is characterized by scattered bunch grasses and patches of the rhizomatous grasses and litter with exposed soil and gravel in the intergrass spaces.
Geographic Range: This western wheatgrass - blue grama grassland is found in the southern Great Plains in the United States, ranging from Colorado and Kansas south to Texas. It occurs in the Oklahoma panhandle, Southeast Colorado and northeast New Mexico, and extends into the western New Mexico mountains.

Nations: US

States/Provinces:  CO, KS, NM, OK, TX


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G5

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.a Little Bluestem - Sideoats Grama - Western Wheatgrass Mixedgrass Prairie Group G133 2.B.2.Nb.2.a
Alliance A4039 Western Wheatgrass - Blue Grama Great Plains Grassland Alliance A4039 2.B.2.Nb.2.a
Association CEGL001578 Western Wheatgrass - Blue Grama Grassland CEGL001578 2.B.2.Nb.2.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Pascopyrum smithii - Bouteloua gracilis Herbaceous Vegetation (Faber-Langendoen 2001)
Concept Author(s): Western Ecology Group

Author of Description: J. Drake, K.S. King, and D. Faber-Langendoen

Acknowledgements: No Data Available

Version Date: 05-24-10
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