Search Field Guide
Advanced Search
MT Gov Logo
Montana Field Guide

Montana Field Guides

Intermountain Sand Grassland
Global Name: Intermountain Open Dune Scrub & Grassland

Global Rank: G4G5
State Rank: S3S4

(see reason below)

External Links




State Rank Reason
This habitat is rare and restricted in range but has not experienced significant declines nor are there significant threats to the persistence on the landscape.
 

General Description
This National Vegetation Classification Group is a locally restricted though ecologically important group in Montana. In Montana, these shrub and herbaceous-dominated communities occur only on sandy sites in the Centennial Valley in the extreme southwestern portion of the state. They occur on both active and stabilized dunes and are characterized by open to sparse (gen <15% total cover) shrub and/or herbaceous vegetation. Some characteristic species include Indian Ricegrass (Oryzopsis hymenoides), Sand Wildrye (Elymus flavescens), Scurfpea (Psoralidium sp), and Rabbitbrushes (Chrysothamnus, Ericameria). Elevations of this type in Montana are from 6,600-7,000 feet with a cool, semi-arid continental climate. Soils range in texture from sand to sandy loams. The specific characteristics of this group in terms of the vegetation communities and dominant species that compose it in Montana in contrast to areas outside of the state requires additional documentation.

This group includes some communities contained within the Active and Stabilized Dune Ecological System.

Diagnostic Characteristics
Sparsely Vegetated; Sandy Soils; Centennial Sandhills; Herbaceous and Short-Shrub Communities

Characteristic Species: Sand Wildrye (Elymus flavescens), Indian Ricegrass (Oryzopsis hymenoides)

Similar Systems

Range
In Montana, this group is restricted to the Centennial Sandhills Region in the Centennial Valley of Beaverhead County.

In Montana, G775 occurs in Level IV Ecoregions: 17af (Centennial Basin)

In Montana, G775 occurs within these Major Land Resource Areas: 44B - Central Rocky Mountain Valleys

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
Beaverhead
Based on 2025 land cover layer.

Spatial Pattern
Large Patch

Environment
This group occurs on sandy sites in the intermountain western U.S. from the Columbia Basin, Great Basin, Centennial Valley in Montana, Wyoming Basins, Colorado Plateau and the San Luis Valley of southern Colorado. Elevations of this type in Montana are from 6,600-7,000ft. Sites occur on active and stable dunes though ours are primarily on stabilized dunes. Vegetation communities range from early-seral communities that colonize bare sand to more stable vegetation communities, particularly on dune margins where gradation into adjacent communities occur. Climate at these sites is a cool, semi-arid continental climate. Soils range in texture from sand to sandy loams.

Vegetation
This group is characterized by an open to sparse (<15% total cover) shrub and/or herbaceous layer. Vegetation cover is sparse and composed of xeromorphic shrubs and dwarf-shrubs and/or a short herbaceous layer that is typically sparse and is dominated by perennial graminoids. The composition of plant species present in Montana Intermountain Sand Dune communities may differ from those in other areas. The Centennial Sandhills Complex is listed as supporting the following plant associations: Artemisia tridentata ssp. tridentata/Festuca idahoensis, Artemisia tridentata (ssp. tridentata)/Stipa comata, Elymus lanceolatus/Phacelia hastata, Stipa comata/Psoralea tenuiflora, Artemisia tripartita/Festuca idahoensis, Artemisia tripartita/Stipa comata, Chrysothamnus viscidiflorus/Stipa comata, and Stipa comata-Psoralidium tenuiflorum (Cooper, S.V., C. Jean, and B.L. Heidel 1999). However, several of these associations are placed into groups other than G775. In contrast to the plant associations listed above, the current NVC classification lists only an Achnatherum hymenoides (syn: Oryzopsis hymenoides)-Psoralidium lanceolatum Grassland Association for Montana. The discrepancy in listed vegetation types and the likely dominant species occurring in Montana Intermountain Sand Dune communities requires additional review.

These sites provide important habitat for several Montana Plant Species of Concern, including Astragalus ceramicus var. apus, Cryptantha fendleri, Sand Wildrye (Elymus flavescens), and Pale Evening-primrose (Oenothera pallida ssp. pallida).

In Montana, this group is represented by 1 Alliance and 1 Association within the National Vegetation Classification. Additional plant associations are likely present within this group that are either undescribed or not attributed to Montana.

National Vegetation Classification

Download the complete NVC hierarchy for Montana

TT5 B05 Desert and Semi-desert
TT5.a S61 Cool Semi-desert
TT5.a1 F121 Cool Desert and Semi-desert Shrub-Steppe
TT5.a1.Na D040 Western North American Cool Semi-Desert Scrub and Grassland
TT5.a1.Na.1 M171 Great Basin-Intermountain Dry Shrubland and Grassland
TT5.a1.Na.1.e G775 Intermountain Open Dune Scrub and Grassland
A4011 Redfieldia flexuosa - Leymus flavescens - Achnatherum hymenoides Grassland Alliance
CEGL001650 Achnatherum hymenoides - Psoralidium lanceolatum Grassland
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
This group occurs primarily on recent sand deposits. Dunes may gradually become stabilized by vegetation when disturbance such as fire are removed from the landscape. Over time, if deposition slows, it will succeed to other shrubland or grassland vegetation types.

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
K.A. Schulz 2015

Montana Version Authors
S. Mincemoyer

Version Date
12/4/2024


References
  • Literature Cited AboveLegend:   View Online Publication
    • Cooper, S.V., C. Jean, and B.L. Heidel. 1999. Plant associations and related botanical inventory of the Beaverhead Mountains Section, Montana. Unpublished report to the Bureau of Land Management. Montana Natural Heritage Program, Helena. 235 pp.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Chadwick, H.W., and P.D. Dalke. 1965. Plant succession on dune sands in Fremont County, Idaho. Ecology 46(6):765-780.
    • Hallock, L. A., R. D. Haugo, and R. Crawford. 2007. Conservation strategy for Washington State inland sand dunes. Washington Natural Heritage Program, Natural Heritage Report 2007-05, prepared for Bureau of Land Management, Spokane, WA. 82 pp.
    • Lesica, P. & S. V. Cooper. 1998. Succession and disturbance in sandhills vegetation: constructing models for managing biological diversity. Conservation Biology 13:293-302.
Login Logout
Citation for data on this website:
Intermountain Sand Grassland.  Montana Field Guide.  Retrieved on , from