Print Report

G141 Pascopyrum smithii - Hesperostipa comata - Schizachyrium scoparium Mixedgrass Prairie Group

Type Concept Sentence: This group is widespread in the northern Great Plains and has scattered occurrences in the western Great Plains; sites are dominated by a mixture of short, medium, and tall grasses, including Andropogon gerardii, Carex inops ssp. heliophila, Carex filifolia, Nassella viridula, Panicum virgatum, Pascopyrum smithii, Schizachyrium scoparium, and Sorghastrum nutans.

Common (Translated Scientific) Name: Western Wheatgrass - Needle-and-Thread - Little Bluestem Mixedgrass Prairie Group

Colloquial Name: Northern Great Plains Mesic Mixedgrass Prairie

Hierarchy Level:  Group

Type Concept: This mixedgrass group is widespread from northern Nebraska into southern Canada. The vegetation is dominated by moderate to moderately dense medium-tall grasses or sometimes, in the western Great Plains and Sandhills region of northwest Nebraska, a mix of tall and medium-tall grasses. Shrubs are usually scattered or absent but can form dense, local patches, particularly in swales or low areas. Dominant species include Pascopyrum smithii, Schizachyrium scoparium, Carex inops ssp. heliophila, and Carex filifolia. In Montana, this includes Festuca idahoensis. Sites with a strong component of Nassella viridula indicate a more favorable moisture balance and perhaps a favorable grazing regime as well because this is one of the most palatable of the midgrasses. Calamovilfa longifolia is often found with high cover values on sandier soils, and Koeleria macrantha cover increases on degraded sites. Common or dominant tallgrasses in the western Great Plains are Andropogon gerardii, Panicum virgatum, and Sorghastrum nutans. Other common species include Bouteloua curtipendula, Bouteloua gracilis, Hesperostipa curtiseta, Hesperostipa neomexicana, Muhlenbergia montana, Pseudoroegneria spicata, Sorghastrum nutans, and Sporobolus cryptandrus. Common woody species include Amelanchier alnifolia, Artemisia cana, Dasiphora fruticosa ssp. floribunda, Juniperus horizontalis, Prunus virginiana, Rhus trilobata, and Symphoricarpos occidentalis. Some examples may range into more of a shrub-steppe. Fire and grazing constitute the primary dynamics affecting this group. Drought can also impact it, in general favoring the shortgrass component at the expense of the midgrasses. With intensive grazing, cool-season exotics such as Poa pratensis, Bromus inermis, and Bromus arvensis can increase in dominance. Shrub species such as Juniperus virginiana can also increase in dominance with fire suppression. Conversion to agriculture likewise has decreased the range of this group. This group occurs on a wide variety of landforms (e.g., mesatops, stream terraces) and in proximity to a diversity of other groups. Soils range from fine-textured loams to sandy or gravelly soils.

Diagnostic Characteristics: This group is dominated by medium-tall graminoids, or tall and medium-tall grasses in the western Great Plains, particularly the midgrasses Nassella viridula, Pascopyrum smithii, and Schizachyrium scoparium and tallgrasses Andropogon gerardii, Panicum virgatum, and Sorghastrum nutans, and occurs in the northwestern Great Plains and along the Front Range south to northeastern New Mexico. The group also includes shrub-dominated sites with abundant Amelanchier alnifolia, Dasiphora fruticosa ssp. floribunda, Juniperus horizontalis, Prunus americana, Prunus virginiana, and Symphoricarpos occidentalis. Sites dominated by Festuca spp. are in a separate group with the exception of Festuca idahoensis stands in Great Plains of central Montana and Wyoming which are left here.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This group originally included all mixedgrass prairies in the northwestern Great Plains, then was split into mesic and dry components (G331 was the dry mixedgrass prairie), was re-formed as a single group, and then re-split into ~Northern Great Plains Dry Mixedgrass Prairie Group (G331)$$ and this group (G141). The range of the group, as currently defined, extends into northeastern New Mexico in the form of western Great Plains tallgrass prairies. The Colorado and New Mexico stands should possibly be moved to a separate group [see ~Andropogon gerardii - Schizachyrium scoparium Western Great Plains Grassland (CEGL001463)$$]. See also Kuchler (1964) type 66.

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 and short grasses interspersed with forbs. Dwarf-shrubs can be dominant in some stands in the northern part of the group''s range and medium or tall shrubs (1-3 m tall) can be locally common to dense.

Floristics: Dominant species include Pascopyrum smithii, Schizachyrium scoparium, Carex inops ssp. heliophila, and Carex filifolia. In Montana, this includes Festuca idahoensis. Sites with a strong component of Nassella viridula indicate a more favorable moisture balance and perhaps a favorable grazing regime as well because this is one of the most palatable of the midgrasses. Calamovilfa longifolia is often found with high cover values on sandier soils, and Koeleria macrantha cover increases on degraded sites. Common or dominant tallgrasses in the western Great Plains are Andropogon gerardii, Panicum virgatum, and Sorghastrum nutans. Other common species include Bouteloua curtipendula, Bouteloua gracilis, Hesperostipa curtiseta, Hesperostipa neomexicana, Muhlenbergia montana, Pseudoroegneria spicata, Sorghastrum nutans, and Sporobolus cryptandrus. Hesperostipa comata may be present but sites where it is abundant are usually too dry for this group. Common woody species include Amelanchier alnifolia, Artemisia cana, Dasiphora fruticosa ssp. floribunda, Juniperus horizontalis, Prunus virginiana, Rhus trilobata, and Symphoricarpos occidentalis.

Dynamics:  Fire and grazing constitute the primary dynamics affecting this group. Drought can also impact it, in general favoring the shortgrass component at the expense of the midgrasses. With intensive grazing, cool-season exotics such as Poa pratensis, Bromus inermis, and Bromus arvensis can increase in dominance. Shrub species such as Juniperus virginiana can also increase in dominance with fire suppression. Conversion to agriculture likewise has decreased the range of this group.
Environmental Description:  This group occurs on a wide variety of landforms and in proximity to a diversity of other groups. Climate and growing season length for the region in which it occurs are intermediate to the shortgrass regions to the west and southwest and the tallgrass regions to the east. Soils range from loams, clay loams, silty clays, and clays to more coarse-textured sandy or gravelly soils. Some examples may include an impermeable or slowly permeable claypan subsoil layer.
Geographic Range: This group occurs throughout the Western Great Plains from northern Nebraska into southern Canada, and west to the western Dakotas and central Montana.

Nations: CA,US

States/Provinces:  AB, MB, MT, ND, NE, SD, SK, 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.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
Alliance A4034 Little Bluestem Northern Mixedgrass Grassland Alliance A4034 2.B.2.Nb.2.c
Alliance A4382 Big Bluestem - Indiangrass Northern Mixedgrass Grassland Alliance A4382 2.B.2.Nb.2.c
Alliance A4383 Creeping Juniper - Skunkbush Sumac - Shrubby-cinquefoil Shrubland Alliance A4383 2.B.2.Nb.2.c
Alliance A4384 Chokecherry - Western Snowberry - Saskatoon Serviceberry Northern Plains Shrubland Alliance A4384 2.B.2.Nb.2.c
Concept Lineage: G331 reactivated & split back out (DFL 10-17-13); G331 merged into G141 (JD 8-22-13)

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: > Bluestem Prairie (601) (Shiflet 1994)
> Bluestem Prairie (710) (Shiflet 1994)
>< Fescue Grassland (613) (Shiflet 1994)
> Wheatgrass (610) (Shiflet 1994)
>< Wheatgrass - Bluestem - Needlegrass (606) (Shiflet 1994)
> Wheatgrass - Grama (609) (Shiflet 1994)
> Wheatgrass - Grama - Needlegrass (608) (Shiflet 1994)
> Wheatgrass - Needlegrass (607) (Shiflet 1994)
>< Wheatgrass - Saltgrass - Grama (615) (Shiflet 1994)
Concept Author(s): S. Menard, in Faber-Langendoen et al. (2011)

Author of Description: S. Menard and J. Drake

Acknowledgements: No Data Available

Version Date: 05-07-15
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