Print Report

G133 Schizachyrium scoparium - Bouteloua curtipendula - Pascopyrum smithii Mixedgrass Prairie Group

Type Concept Sentence: This group occurs in the central Great Plains where grasslands are dominated by Bouteloua curtipendula, Pascopyrum smithii, and Schizachyrium scoparium, often with tallgrass or shortgrass species present to codominant.

Common (Translated Scientific) Name: Little Bluestem - Sideoats Grama - Western Wheatgrass Mixedgrass Prairie Group

Colloquial Name: Central Great Plains Mixedgrass Prairie

Hierarchy Level:  Group

Type Concept: This mixedgrass prairie group ranges from central Nebraska into the Rolling Plains and the western Edwards Plateau of Texas. The loessal regions in west-central Kansas and central Nebraska, the Red Hills region of south-central Kansas and northern Oklahoma are all located within this group. Because of its proximity to other ecoregions, this group contains elements from both shortgrass and tallgrass prairies, which combine to form the mixedgrass prairie group throughout its range. The distribution, species richness and productivity of plant species within the mixedgrass group is controlled primarily by environmental conditions, in particular soil moisture and topography. Grazing and fire are important dynamic processes in this group. The relative dominance of the various grass and forb species within different associations in the group also can strongly depend on the degree of natural or human disturbance. This group can contain grass species such as Andropogon gerardii, Hesperostipa comata, and Sporobolus heterolepis, although the majority of the associations within the region are dominated by Pascopyrum smithii or Schizachyrium scoparium, often with substantial Bouteloua gracilis or Bouteloua curtipendula. Muhlenbergia reverchonii can be a dominant in the southern part of the group''s range. Numerous forb and sedge species (Carex spp.) can also occur within the mixedgrass group in the western Great Plains. Bouteloua dactyloides and Yucca glauca can be common in drier or overgrazed areas. Some common forb species include Ambrosia psilostachya, Echinacea angustifolia, and Lygodesmia juncea. Oak species such as Quercus macrocarpa can occur also in areas protected from fire due to topographic position, which may resemble an oak savanna, and fire suppression may result in a closed canopy and expansion of bur oak beyond sheltered areas. Likewise, within the mixedgrass prairie, small seeps may occur, especially during the wettest years. Although these are not considered a separate group, the suppression of fire within the region has enabled the invasion of both exotics and some shrub species such as Juniperus virginiana and also allowed for the establishment of Pinus ponderosa in the northwestern parts of the range.

Diagnostic Characteristics: This group contains elements from both shortgrass prairies to the west and tallgrass prairies to the north and east, which combine to form the mixedgrass prairie group throughout its range. Dominance by some combination of Schizachyrium scoparium, Bouteloua curtipendula, and Bouteloua gracilis in the central Great Plains is characteristic.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This group was originally split into a dry group and a mesic group. It was combined into one group as the difference between mesic and dry appeared more appropriately separated at the alliance level. This type does not extend north into Wyoming (G. Jones pers. comm. 2019). See also Central Mixedgrass Ecological System map in Comer et al. (2018) and the Kuchler (1964) type 69.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The vegetation is characterized by a dense to sparse mixture of tall, mid, and short grasses interspersed with forbs. Woody vegetation is uncommon in most examples but can become common in the prolonged absence of fire, especially in the wetter, eastern part of this group''s range.

Floristics: This group typically contains mixedgrass species such as Pascopyrum smithii, Bouteloua curtipendula, Schizachyrium scoparium, Hesperostipa comata, Sporobolus heterolepis, and Bouteloua gracilis. Some tallgrass species may be common, such as Andropogon gerardii, Sorghastrum nutans, and Panicum virgatum. Bouteloua dactyloides (= Buchloe dactyloides) can become common on overgrazed sites. Common forb species include Ambrosia psilostachya, Echinacea angustifolia, and Lygodesmia juncea. Scattered patches of trees, often Juniperus virginiana and Quercus macrocarpa but also Pinus ponderosa in the northwest, and shrubs, typically Artemisia filifolia (on sandier soils), Gutierrezia sarothrae, Prosopis glandulosa (in the south), Prunus virginiana, and Yucca glauca, occur in some stands and these can increase in the prolonged absence of fire.

Dynamics:  Fire and grazing are the primary processes occurring within the group. The diversity in this mixedgrass group likely reflects both the short- and long-term responses of the vegetation to these often concurrent disturbance regimes. Fire suppression and overgrazing can lead to the invasion of woody species such as Juniperus virginiana and Pinus ponderosa. Likewise, fire suppression may lead to a more closed canopy of Quercus macrocarpa.
Environmental Description:  Topographic and soil characteristics also vary across the range of this group. It is often characterized by rolling to extremely hilly landscapes with soils developed from loess, shale, limestone, or sandstone parent material. Mollisol soils are most prevalent and range from silt loams and silty clay loams with sandy loams possible on the western edge of the range. The Red Hills region of Kansas and Oklahoma, which contains examples of this group, contains somewhat unique soil characteristics and has developed from a diversity of sources including red shale, red clay, sandy shale, siltstone, or sandstone. These soils have developed a characteristic reddish color from the primary material. They can consist of silt, loam, or clay and can have textures ranging from fine sandy loam to a more clayey surface.
Geographic Range: This group is found throughout the central and southern areas of the Western Great Plains ranging from southern South Dakota and possibly southern North Dakota into Texas with a few occurrences in the tallgrass-dominated landscapes of western Iowa, eastern Nebraska, and northwestern Missouri.

Nations: CA,MX?,US

States/Provinces:  CO, KS, MXCOA?, NE, NM, OK, TX


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.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 A4038 Skunkbush Sumac Great Plains Shrubland Alliance A4038 2.B.2.Nb.2.a
Alliance A4039 Western Wheatgrass - Blue Grama Great Plains Grassland Alliance A4039 2.B.2.Nb.2.a
Alliance A4040 Seep Muhly Grassland Alliance A4040 2.B.2.Nb.2.a
Alliance A4042 Little Bluestem - Sideoats Grama Central Plains Grassland Alliance A4042 2.B.2.Nb.2.a
Alliance A4677 Big Bluestem Central Mixedgrass Grassland Alliance A4677 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: > Blue Grama - Western Wheatgrass (704) (Shiflet 1994)
< Bluestem - Grama (709) (Shiflet 1994)
> Bluestem - Grama Prairie (604) (Shiflet 1994)
> Eastern Redcedar: 46 (Eyre 1980) [Only on really degraded sites.]
Concept Author(s): S. Menard and K. Kindscher, in Faber-Langendoen et al. (2011)

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

Acknowledgements: B. Hoagland

Version Date: 05-07-15
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