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Montana Field Guide

Montana Field Guides

Great Plains Dry Mixedgrass Prairie
Global Name: Northern Great Plains Dry Mixedgrass Prairie

Global Rank: G3?
State Rank: S4

(see reason below)

External Links




State Rank Reason
These prairie grasslands have declined in condition and extent and face continued threats from invasive species, grazing, development and conversion to agricultural uses. However, they are still common, widespread and relatively secure.
 

General Description
This National Vegetation Classification Group of Dry Mixedgrass Prairie is the dominant grassland group across the prairie region in Montana. It is characterized by sparse to dense cover of various short to mid-statured, perennial grasses. Some sites within this group support a short or dwarf-shrub component with a layer of grasses. Dominant species include the following cool season grasses; Needle-and-Thread (Stipa comata), Western Wheatgrass (Elymus smithii), Bluebunch Wheatgrass (Elymus spicatus), Thickspike Wheatgrass (Elymus lanceolatus) and Prairie Junegrass (Koeleria macrantha) Blue Grama (Bouteloua gracilis) and Little Bluestem (Schizachyrium scoparium) are common warm-season grass at some sites. Upland sedges, such as Carex inops ssp. heliophila and Carex filifolia, are important components of some sites. Short and dwarf-shrubs are common components of some mixedgrass prairie communities and as a result, the Dry Mixedgrass Prairies transition readily into shrub-steppe communities of G302 and G310 as well as some Badlands and Sparsely-Vegetated communities. More mesic grassland sites are part of the much less common G141 - Great Plains Mesic Mixedgrass Prairie while sandy sites are part of G889 - Great Plains Sand Prairie. This group is separated from G141 - Great Plains Mixedgrass Prairie Group based on soil moisture and species composition. Stronger constancy and dominance of the short and mid grasses, distinguish this type from the related mesic mixedgrass types. Strong grazing pressures on mesic mixedgrass prairies, which increases the shortgrass component, can blur the distinction between the two types.

This group includes the majority of the Great Plains Mixedgrass Prairie Ecological System excluding the more mesic communities.

Diagnostic Characteristics
Shortgrass Prairie; Warm and Cool Season Grasses; Graminoids >25% Cover; Great Plains Region

Typical Dominants: Little Bluestem (Schizachyrium scoparium), Blue Grama (Bouteloua gracilis) Needle-and-Thread (Stipa comata), Prairie Junegrass (Koeleria macrantha), Western Wheatgrass (Elymus smithii), Thickspike Wheatgrass (Elymus lanceolatus), Bluebunch Wheatgrass (Elymus spicatus), Carex filifolia and Carex inops ssp. heliophila

Similar Systems

Range
This group occurs in the Great Plains of central and eastern Montana extending west to the foothills of the Rocky Mountains. It is the dominant grassland type across the plains and prairie region.

In Montana, G331 occurs in Level III Ecoregions: 42 (Northwestern Glaciated Plains) and 43 (Northwestern Great Plains).

In Montana, G331 occurs or potentially occurs within these Major Land Resource Areas: 46 Northern and Central Rocky Mountain Foothills, 52 - Brown Glaciated Plains; 53A - Northern Dark Brown Glaciated Plains; 53B - Central Dark Brown Glaciated Plains; 54 - Rolling Soft Shale Plain, 58A,B,C,D - Northern Rolling High Plains, 60A,B - Pierre Shale Plains.

Density and Distribution
Based on 2025 land cover layer. Grid on map is based on USGS 7.5 minute quadrangle map boundaries.



Mapped Distribution by County
Big Horn, Blaine, Broadwater, Carbon, Carter, Cascade, Chouteau, Custer, Daniels, Dawson, Fallon, Fergus, Gallatin, Garfield, Glacier, Golden Valley, Hill, Judith Basin, Lewis and Clark, Liberty, Mccone, Meagher, Musselshell, Park, Petroleum, Phillips, Pondera, Powder River, Prairie, Richland, Roosevelt, Rosebud, Sheridan, Stillwater, Sweet Grass, Teton, Toole, Treasure, Valley, Wheatland, Wibaux, Yellowstone
Based on 2025 land cover layer.

Spatial Pattern
Matrix

Environment
This group is generally found in a semi-arid climate with cold winters and hot summer temperatures. Precipitation is most abundant during convective summer storms along with winter snowfall and spring rains. Sites occur primarily on flat to rolling topography with some low-relief hummocky areas. Surficial materials are predominantly glacial till to the north of the Missouri River, with some glacio-lacustrine areas. Glacio-fluvial sediments are common along major river valleys, and eolian materials are prevalent in some areas (Adams et al. 2013). Predominant soils are deep and well-drained to imperfectly drained, and have a thick, dark A horizon. Textures range from loam to sandy loam. Significant areas of Solonetzic soils, characterized by a subsoil hardpan layer with a high proportion of sodium can be found in some areas (Adams et al. 2013).

Vegetation
The vegetation of this group is characterized by a sparse to dense cover of various short to mid-statured, perennial grasses. Both bunchgrasses and rhizomatous grasses are represented, and sites may be dominated by one or the other or contain a mix of both types. Some sites within this group support a short or dwarf-shrub component with a layer of grasses. Dominant species include the following cool season grasses; Needle-and-Thread (Stipa comata), Western Wheatgrass (Elymus smithii), Bluebunch Wheatgrass (Elymus spicatus), Thickspike Wheatgrass (Elymus lanceolatus) and Prairie Junegrass (Koeleria macrantha) Blue Grama (Bouteloua gracilis) and Little Bluestem (Schizachyrium scoparium) are common warm-season grass at some sites. Upland sedges, such as Carex inops ssp. heliophila and Carex filifolia, are important components of some sites. Short and dwarf-shrubs are common components of some mixedgrass prairie communities, including Skunkbush Sumac (Rhus trilobata), Creeping Juniper (Juniperus horizontalis), Rubber Rabbitbrush (Ericameria nauseosa), Wyoming Big Sagebrush (Artemisia tridentata ssp. wyomingensis), Gardner’s Saltbush (Atriplex gardneri), and Winterfat (Krascheninnikovia lanata). The Plains Pricklypear (Opuntia polyacantha) is a common component of this group. Forbs may be sparsely to moderately represented and the diversity can vary widely across the type.

As currently defined, this group includes 6 Alliances and 18 Associations within the National Vegetation Classification in Montana. However, A2302 - Artemisia tridentata/Pascopyrum smithii Shrub Grassland Alliance and its 2 Associations appear to be better placed into G302 - Intermountain Basins Big Sagebrush Steppe with other Wyoming Big Sagebrush Shrub Steppe communities. Additionally, CEGL001330 - Ericameria nauseosa/Pseudoroegneria spicata Shrubland appears to be better placed with G310 - Rabbitbrush - Arid Steppe and Shrubland.

National Vegetation Classification

Download the complete NVC hierarchy for Montana

TT4 B04 Temperate-Boreal Grassland and Shrubland
TT4.b S58 Temperate Grassland and Shrubland
TT4.b1 F116 Temperate Lowland-Montane Grassland and Shrubland
TT4.b1.Nf D023 Central North American Grassland and Shrubland
TT4.b1.Nf.3 M051 Great Plains Mixedgrass and Fescue Prairie
TT4.b1.Nf.3.c G331 Northern Great Plains Dry Mixedgrass Prairie
A2303 Atriplex gardneri / Hesperostipa comata - Distichlis spicata Saline Dwarf-Shrubland and Grassland Alliance
CEGL001445 Atriplex gardneri / Hesperostipa comata - Distichlis spicata Saline Dwarf-Shrubland and Grassland
A3586 Artemisia cana / Hesperostipa comata - Pascopyrum smithii Shrubland Alliance
CEGL001072 Artemisia cana / Pascopyrum smithii Shrubland
CEGL001553 Artemisia cana ssp. cana / Hesperostipa comata Shrubland
CEGL001556 Artemisia cana ssp. cana / Pascopyrum smithii Shrubland
A4032 Pseudoroegneria spicata - Pascopyrum smithii - Hesperostipa comata Grassland Alliance
CEGL001663 Pseudoroegneria spicata - Bouteloua curtipendula Grassland
A4383 Northern Plains Low Shrub Grassland Alliance
CEGL001393 Juniperus horizontalis / Carex inops ssp. heliophila Dwarf-shrubland
CEGL001394 Juniperus horizontalis / Schizachyrium scoparium Dwarf-shrubland
CEGL001504 Rhus trilobata / Carex filifolia Shrub Grassland
CEGL001506 Rhus trilobata / Schizachyrium scoparium Shrub Grassland
A4389 Hesperostipa comata - Pascopyrum smithii - Bouteloua gracilis Grassland Alliance
CEGL001579 Pascopyrum smithii - Bouteloua gracilis - Carex filifolia Grassland
CEGL001700 Hesperostipa comata - Carex filifolia Grassland
CEGL001701 Hesperostipa comata - Carex inops ssp. heliophila Grassland
CEGL008297 Hesperostipa comata - Bouteloua gracilis - Carex filifolia Northern Grassland
CEGL008298 Krascheninnikovia lanata / Hesperostipa comata Great Plains Dwarf-shrubland
View more information on the NVC standard in Montana
*Disclaimer: Some Alliances and Associations are considered provisional. Some require further documentation to verify their occurrence in the state and some may be modified or deleted in future revisions after collection of additional data and information.

Dynamic Processes
Fire, drought, and grazing constitute the primary dynamics affecting this group (Adams et al. 2013).

Management
Western Wheatgrass and Thickspike Wheatgrass will decline in abundance with grazing pressure, while Blue Grama and Prairie Junegrass cover increases on degraded sites.

Restoration Considerations
See Adams et al. (2013) for a discussion of the recovery of dry mixedgrass prairie following cultivation and abandonment.

Species Associated with this Community
  • How Lists Were Created and Suggested Uses and Limitations
    Animal Species Associations
    Please note that while all vertebrate species have been systematically associated with vegetation communities, only a handful of invertebrate species have been associated with vegetation communities and invertebrates lists for each vegetation community should be regarded as incomplete. Animal species associations with natural vegetation communities that they regularly breed or overwinter in or migrate through were made by:
    1. Using personal observations and reviewing literature that summarize the breeding, overwintering, or migratory habitat requirements of each species (Dobkin 1992, Hart et al. 1998, Hutto and Young 1999, Maxell 2000, Werner et al. 2004, Adams 2003, and Foresman 2012);
    2. Evaluating structural characteristics and distribution of each vegetation community relative to the species' range and habitat requirements;
    3. Examining the observation records for each species in the state-wide point observation database associated with each vegetation community;
    4. Calculating the percentage of observations associated with each vegetation community relative to the percent of Montana covered by each vegetation community to get a measure of "observations versus availability of habitat".
    Species that breed in Montana were only evaluated for breeding habitat use. Species that only overwinter in Montana were only evaluated for overwintering habitat use. Species that only migrate through Montana were only evaluated for migratory habitat use. In general, species are listed as associated with a vegetation community if it contains structural characteristics known to be used by the species. However, species are not listed as associated with a vegetation community if we found no support in the literature for the species’ use of structural characteristics of the community even if point observations were associated with it. If you have any questions or comments on animal species associations with vegetation communities, please contact the Montana Natural Heritage Program's Senior Zoologist.

    Plant Species Associations
    Please note that while diagnostic, dominant, or codominant vascular plant species for a vegetation community have been systematically assigned to those communities and vascular plant Species of Concern were systematically evaluated for their associations with vegetation communities, the majority of Montana’s vascular plant species have not been evaluated for their associations with vegetation communities and no attempt has been made to associate non-vascular plants, fungi, or lichens with vegetation communities. Plant species associations with natural vegetation communities were made in a manner similar to that described above for animals, but with review of Lesica et al. (2022) and specimen collection data from the Consortium of Pacific Northwest Herbaria. If you have any questions or comments on plant species associations with vegetation communities, please contact the Montana Natural Heritage Program's Program Botanist.

    Suggested Uses and Limitations
    Species associations with vegetation communities should be used to generate potential lists of species that may occupy broader landscapes for the purposes of landscape-level planning. These potential lists of species should not be used in place of documented occurrences of species or predicted habitat suitability models (this information can be requested at: https://mtnhp.mt.gov/requests/), or systematic surveys for species and onsite evaluations of habitat by trained biologists. Users of this information should be aware that the land cover data used to generate species associations is based on satellite imagery from 2016 and was only intended to be used at broader landscape scales. Land cover mapping accuracy is particularly problematic when the vegetation communities occur as small patches or where the land cover types have been altered over the past decade. Thus, particular caution should be used when using the associations in assessments of smaller areas (e.g., evaluations of public land survey sections). Finally, although a species may be associated with a particular vegetation community within its known geographic range, portions of that vegetation community may occur outside of the species' known geographic range.

    Literature Cited
    • Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
    • Consortium of Pacific Northwest Herbaria. https://www.pnwherbaria.org/ Last accessed May 30, 2025.
    • Dobkin, D. S. 1992. Neotropical migrant land birds in the Northern Rockies and Great Plains. USDA Forest Service, Northern Region. Publication No. R1-93-34. Missoula, MT.
    • Foresman, K.R. 2012. Mammals of Montana. Second edition. Mountain Press Publishing, Missoula, Montana. 429 pp.
    • Hart, M.M., W.A. Williams, P.C. Thornton, K.P. McLaughlin, C.M. Tobalske, B.A. Maxell, D.P. Hendricks, C.R. Peterson, and R.L. Redmond. 1998. Montana atlas of terrestrial vertebrates. Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT. 1302 p.
    • Hutto, R.L. and J.S. Young. 1999. Habitat relationships of landbirds in the Northern Region, USDA Forest Service, Rocky Mountain Research Station RMRS-GTR-32. 72 p.
    • Lesica P., M. Lavin, and P.F. Stickney. 2022. Manual of vascular plants, 2nd Edition. Brit Press. 779 p.
    • Maxell, B.A. 2000. Management of Montana's amphibians: a review of factors that may present a risk to population viability and accounts on the identification, distribution, taxonomy, habitat use, natural history, and the status and conservation of individual species. Report to U.S. Forest Service Region 1. Missoula, MT: Wildlife Biology Program, University of Montana. 161 p.
    • Werner, J.K., B.A. Maxell, P. Hendricks, and D. Flath. 2004. Amphibians and reptiles of Montana. Missoula, MT: Mountain Press Publishing Company. 262 p.

Original Concept Authors
S. Menard, L. Allen and J. Drake 2015

Montana Version Authors
S. Mincemoyer

Version Date
12/4/2024


References
  • Literature Cited AboveLegend:   View Online Publication
    • Adams, B. W., J. Richman, L. Poulin-Klein, K. France, D. Moisey, and R. L. McNeil. 2013. Range plant communities and range health assessment guidelines for the dry mixedgrass natural subregion of Alberta. Second approximation. Publication No. T/040. Rangeland Management Branch, Policy Division, Alberta Environment and Sustainable Resource Development. Lethbridge, AB.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Barbour, Michael G. 2000. North American terrestrial vegetation. Cambridge: Cambridge University Press.

    • Coupland, R.T. 1961. A reconsideration of grassland classification in the northern great plains of North America. Journal of Ecology 49(1): 135-167.
    • DeVelice, R.L., S.V. Cooper, J.T. McGarvey, J. Lichthardt, and P.S. Bourgeron. 1995. Plant communities of northeastern Montana: A first approximation. Montana Natural Heritage Program, Helena, MT. 116 pp.
    • Looman, J. 1980. The vegetation of the Canadian prairie provinces. II. The grasslands, Part 1. Phytocoenologia 8(2):153-190.
    • Shiflet, T. N., editor. 1994. Rangeland cover types of the United States. Society for Range Management. Denver, CO. 152 pp.
    • Singh, J. S., W. K. Lauenroth, R. K. Heitschmidt and J. L. Dodd. 1983. Structural and functional attributes of the vegetation of northern mixed prairie of North America. The Botanical Review 49:117-149.
    • Umbanhowar, Charles Edward. 1996. "Recent Fire History of the Northern Great Plains". American Midland Naturalist. 135 (1): 115-121.
    • Weaver, J.E., F.W. Albertson, B.W. Allred, and A. Heerwagen. 1956. Grasslands of the Great Plains: their nature and use. Lincoln, NE: Johnsen Publishing Company. 395 p.
    • Wilson, S. D., and A. K. Gerry. 1995. 'Strategies for Mixed-Grass Prairie Restoration: Herbicide, Tilling, and Nitrogen Manipulation'. Restoration Ecology. 3 (4): 290-298.
    • Wright, J. C. and E. A. Wright. 1948. Grassland types of south central Montana. Ecology 29:449-460.
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Citation for data on this website:
Great Plains Dry Mixedgrass Prairie.  Montana Field Guide.  Retrieved on , from