Mountain Big Sagebrush Shrubland
Global Name:
Intermountain Montane Sagebrush Steppe
Global Rank:
G4G5
State Rank:
S4
(see reason below)
External Links
State Rank Reason
This habitat is widespread and abundant in some areas. Decreases in habitat condition and extent have occurred and continue to occur. Threats from non-native species and grazing practices continue to be concerns but the abundance of the type limits overall impacts and concern.
General Description
This National Vegetation Classification Group is a semi-arid shrub and shrub-steppe group. It dominates the non-forested, montane and subalpine landscape of southwestern Montana from valley bottoms to subalpine ridges. It is found as far north as Glacier National Park and can also be seen in the island mountain ranges of the north-central and south-central portions of the state. The shrub component of this group is dominated by Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana). Rarely are sites dominated by Subalpine Big Sagebrush (Artemisia spiciformis, Artemisia tridentata ssp. spiciformis) in extreme southern Montana. Other co-dominant shrubs include Silver Sagebrush (Artemisia cana ssp. viscidula) and Mountain Snowberry (Symphoricarpos oreophilus). It primarily occurs on deep-soiled to stony flats, ridges, nearly flat ridgetops, and mountain slopes. In general, this group occurs in areas of gentle topography, fine soils, subsurface moisture or mesic conditions, within zones of higher precipitation and areas of snow accumulation. It occurs on all slopes and aspects, variable substrates and all soil types. Low Sagebrush (Artemisia arbuscula) shrublands may be found on adjacent sites in southwestern Montana on less productive, shallower, rockier soils. Graminoids and forbs are often common at these sites. In areas where sagebrush has been eliminated by human activities like burning, disking or poisoning, other shrubs may be dominant, especially rubber rabbitbrush (Ericameria nauseosa), and Green Rabbitbrush (Chrysothamnus viscidiflorus). Shrub canopy cover is extremely variable, ranging from 10 percent to as high as 50 percent at some sites.
This group is largely equivalent to the Montane Sagebrush Steppe Ecological System.
Diagnostic Characteristics
Montane and subalpine zones; Shrubland and Steppe; Rocky Mountain Region; Xeromorphic Shrubs; Shrub Cover >10%; Bunchgrasses; Deep, Aridic Soils.
Typical Dominants: Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana), Snowfield or Spiked Big Sagebrush (Artemisia spiciformis)
Similar Systems
Range
In Montana, this group is a landscape dominant of southwestern Montana from the higher valleys to subalpine ridges and is found as far north as Glacier National Park in western Montana. Mountain Big Sagebrush Shrublands also occur in the island mountain ranges of central and southern MT.
In MT, G304 occurs within these Level III Ecoregions: 15 (Northern Rockies), 16 (Idaho Batholith), 17 (Middle Rockies) and 41 (Canadian Rockies)
In Montana, G304 occurs within these Major Land Resource Areas: 43A - Northern Rocky Mountains, 43B - Central Rocky Mountains, 44B - Central Rocky Mountain Valleys, and 46 - Northern and Central Rocky Mountain Foothills
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, Big Horn, Blaine, Broadwater, Carbon, Cascade, Chouteau, Deer Lodge, Fergus, Gallatin, Golden Valley, Granite, Hill, Jefferson, Judith Basin, Lewis and Clark, Liberty, Madison, Meagher, Missoula, Park, Phillips, Powell, Ravalli, Silver Bow, Stillwater, Sweet Grass, Wheatland
Based on 2025 land cover layer.
Spatial Pattern
Large Patch
Environment
This group occurs primarily in the montane and subalpine zones. In southwestern Montana, it is found from 6,000-10,500 feet (Lesica et al 2005). In northwestern MT, it occurs down to 3,000 feet while in central Montana it is mostly found between 4,000 and 6,500 feet. Precipitation ranges from 15 inches in valley locations to upwards of 35 inches along the mountain crests. Snowfall accounts for substantial portions of the annual precipitation. Temperatures are continental with large annual and diurnal variations. In general, this group shows an affinity for gentle topography. Soils are generally moderately deep to deep, well-drained, and loam, sandy loam, clay loam, or gravelly loam textural classes. Soils often have a substantial volume of coarse fragments, and are derived from a variety of parent materials. This type primarily occurs on deep-soiled to stony flats, ridges, nearly flat ridgetops, and mountain slopes, but at high elevation, is typically restricted to south- or west-facing slopes.
Vegetation
In Montana, this group is dominated by and/or defined by Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana) which forms stands that are generally 0.5-1 meter in height. Silver Sagebrush (Artemisia cana ssp. viscidula) and/or Subalpine Big Sagebrush (Artemisia spiciformis or A. tridentata ssp. spiciformis) are rarely co-dominant on some sites. Other shrubs may be present, but usually have low cover (5-10%). Species include Rubber Rabbitbrush (Ericameria nauseosa), and Green Rabbitbrush (Chrysothamnus viscidiflorus), Mountain Snowberry (Symphoricarpos oreophilus), Wax Currant (Ribes cereum), and Woods’ Rose (Rosa woodsii). Wyoming Big Sagebrush (Artemisia tridentata ssp. wyomingensis) generally occurs at elevations below Mountain sagebrush in areas where they co-occur.
The herbaceous layer is usually well represented to abundant with cover generally over 25%. Common graminoids include Rough Fescue (Festuca campestris), Idaho Fescue (Festuca idahoensis), Bluebunch Wheatgrass (Elymus spicatus), Slender Wheatgrass (Elymus trachycaulus), Mountain Brome (Bromus carinatus), Prairie Junegrass (Koeleria macrantha), Sandberg’s Bluegrass (Poa secunda), Bottlebrush Squirreltail (Elymus elymoides), Nelson's Needlegrass (Stipa nelsonii), Spike Fescue (Leucopoa kingii), and Timber Oatgrass (Danthonia intermedia). A variety of dry, upland sedges such as Threadleaf Sedge (Carex filifolia) and Geyer’s Sedge (Carex geyeri) are often present (Mueggler and Stewart 1988).
Forb diversity is often moderate to high, commonly exceeding 30 species in a 400 m2 macroplot. Species may include Arrowleaf Balsamroot (Balsamorhiza sagittata), Indian Paintbrush (Castilleja species), Sandwort (Arenaria congesta), Cinquefoil (Potentilla species), Fleabane (Erigeron species), Phlox (Phlox species), Milkvetch (Astragalus species), Prairie Smoke (Geum triflorum), Lupine (Lupinus species), Buckwheat (Eriogonum species), Common Yarrow (Achillea millefolium), Rosy Pussytoes (Antennaria rosea), Wild Strawberry (Fragaria virginiana), and Western Sagewort (Artemisia ludoviciana). Plains Pricklypear (Opuntia polyacantha) is common on sites in southwestern Montana (Cooper et al 1999). Weeds, particularly Cheatgrass may be abundant as some sites. Mosses and lichens may be common on some sites with the mosses usually confined to areas underneath the shrub canopy. Lichens may occur on the soil surface, on rocks or on woody debris.
In Montana, this group is represented by 9 Associations grouped into 3 Alliances within the National Vegetation Classification, which likely covers the range of types within the state in Mountain Big Sagebrush communities.
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.3 M169 Great Basin-Intermountain Tall Sagebrush Steppe
TT5.a1.Na.3.c G304 Intermountain Montane Sagebrush Steppe
A2310 Artemisia spiciformis Shrub Steppe Alliance
A2311 Artemisia tridentata ssp. vaseyana Shrub Steppe Alliance
A3208 Artemisia tridentata ssp. vaseyana - Symphoricarpos oreophilus Shrub Steppe Alliance
*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
The natural fire regime has been greatly altered within these communities, and therefore shrub cover can be highly variable. Big sagebrush is easily killed by fire at all intensities, and when exposed to fire, plants do not re-sprout (Wright et al, 1979). In southwestern Montana, Wambolt etal (2001) and Lesica etal (2005) have also shown that fire in big sagebrush is stand-replacing, killing or removing most of the above-ground vegetation, and that recovery to pre-burn cover (of sagebrush) may require 15 or more years for basin big sagebrush, and on average approximately 32 years for mountain big sagebrush (Lesica et al 2005, Cooper et al. 2007).
Management
Fire and grazing can alter these habitats but can also be used for management. Overgrazing reduces native bunchgrasses and often allows an increase in exotic grasses such as Kentucky bluegrass (Poa pratensis) or Cheatgrass. However, managed grazing can be used to reduce unnaturally high fuel loads. In the absence of natural fire, periodic prescribed burns can be used to maintain and restore sagebrush steppe to pre-settlement conditions. Low intensity prescribed fire is used to reduce sagebrush cover and to increase herbaceous forage and improve habitat quality for sage grouse and other wildlife by creating a mosaic of burned and unburned patches. Results in southwestern Montana indicate that prescribed fire resulted in an average increase of 13% in grass canopy cover, followed by light grazing, this may be a way of rejuvenating mountain big sagebrush stands. Prescribed fire or wildfire will induce only a small increase in the cover of forbs and will have no effect on the abundance of plants in the Cichorieae tribe of the Asteraceae, an important food source for rearing sage grouse broods (Lesica et al 2005). In areas where sage has been eliminated by human activities like burning, disking or poisoning, other shrubs may dominate the steppe system. This can be seen around Garrison and Deer Lodge, where the sage steppe communities contain only minimal amounts of sage.
Restoration Considerations
Severely burned sites may require replanting with mountain big sagebrush seedlings due to the slow recovery time and low rates of natural seedling recruitment. Generally, larger container volume of nursery stock results in higher outplanting success; 10 to 20 cubic inch container stock is recommended for use on these sites.
Big sagebrush has been shown to consist of subspecies and ecotypes that are morphologically and ecologically distinct. Collecting seeds from the appropriate subspecies in the proposed out-planting site is recommended (Mahalovich and McArthur 2004). The native distribution of each subspecies serves as the geographic boundary for each seed collection zone, with the additional restriction that seeds and plants should not be moved further than 483 km (300 mi) to their target planting site. These seed transfer guidelines are an indication of the habitat requirements of the subspecies.
The presence of polyploidy in some plant species is also an important factor to consider in local adaptation. Polyploidy can influence plant fertility and vigor and polyploids are often better adapted to extreme ecological environments than diploids (Sanderson et al 1989; McArthur and Sanderson 1999). Thus, specific ecotypes or ploidy level of big sagebrush may also be useful for selecting seed sources for outplanting on droughty or mineral soils (Mahalovich and McArthur 2004).
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:
- 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);
- Evaluating structural characteristics and distribution of each vegetation community relative to the species' range and habitat requirements;
- Examining the observation records for each species in the state-wide point observation database associated with each vegetation community;
- 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.
- Species of Concern Associated with this Community
Vascular Plants
Mammals
Birds
Reptiles
Amphibians
- Diagnostic, Dominant, or Codominant Plant Species for this Community
Vascular Plants
- Other Native Species Commonly Associated with this Community
Vascular Plants
Original Concept Authors
M.E. Hall and K.A. Schulz 2015
Montana Version Authors
S. Mincemoyer, L. Vance, T. Luna, S.V. Cooper
Version Date
12/5/2024
References
- Literature Cited AboveLegend:
View Online Publication- Lesica, P., S.V. Cooper, and G.M. Kudray. 2005. Big sagebrush shrub-steppe postfire succession in southwest Montana. Prepared for U.S. Department of the Interior, Bureau of Land Management, Dillon Field Office. Montana Natural Heritage Program, Helena, MT. 29 pp. plus appendices.
Mahalovich, Mary F., and E. Durant McArthur. 2004. 'Sagebrush (Artemisia spp.) Seed and Plant Transfer Guidelines'. Native Plants Journal. 5 (2): 141-148.- McArthur, E. Durant, and Stewart C. Sanderson. 1999. "Cytogeography and Chromosome Evolution of Subgenus Tridentatae of Artemisia (Asteraceae)". American Journal of Botany. 86 (12): 1754-1775.
- Sanderson SC, McArthur ED, Stutz HC. 1989. A relationship between polyploidy level and habitat in western shrub species. In: Wallace A, McArthur ED, Haferkamp MR, editors. Proceedings: symposium on shrub ecophysiology and biotechnology.1987. June 30-July 2; Logan, UT. Ogden, UT: U.S. Department of Agriculture. Forest Service. Intermountain Research Station; p 23-30.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Mueggler, W. F. and W. L. Stewart. 1980. Grassland and shrubland habitat types of western Montana. USDA Forest Service Gen. Tech. Rep. INT-66, Intermountain Forest and Range Exp. Sta., Ogden, Utah. 154 pp.
- Shiflet, T. N., editor. 1994. Rangeland cover types of the United States. Society for Range Management. Denver, CO. 152 pp.
- West, N. E. 1983c. Western Intermountain sagebrush steppe. Pages 351-374 in: N. E. West, editor. Temperate deserts and semi-deserts. Ecosystems of the world, Volume 5. Elsevier Publishing Company, Amsterdam.
- Web Search Engines for Articles on "Intermountain Montane Sagebrush Steppe"
