Montane Sagebrush Steppe
Provisional State Rank
This system dominates the montane and subalpine landscape of southwestern Montana from valley bottoms to subalpine ridges and is found as far north as Glacier National Park. It can also be seen in the island mountain ranges of the north-central and south-central portions of the state. It primarily occurs on deep-soiled to stony flats, ridges, nearly flat ridgetops, and mountain slopes. In general, this system 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. The shrub component of this system is generally dominated by mountain big sagebrush (Artemisia tridentata ssp. vaseyana). Other co-dominant shrubs include silver sagebrush (Artemisia cana ssp. viscidula), subalpine big sagebrush (Artemisia tridentata ssp. spiciformis), three tip sagebrush (Artemisia tripartita ssp. tripartita) and antelope bitterbrush (Purshia tridentata). Little sagebrush (Artemisia arbuscula ssp. arbuscula) shrublands are only found in southwestern Montana on sites with a perched water table. Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) sites may be included within this system if occurrences are at montane elevations, and are associated with montane graminoids such as Idaho fescue (Festuca idahoensis), spike fescue (Leucopoa kingii), or poverty oatgrass (Danthonia intermedia). In ares where sage 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). Because of the mesic site conditions, most occurrences support a diverse herbaceous undergrowth of grasses and forbs. Shrub canopy cover is extremely variable, ranging from 10 percent to as high as 40 or 50 percent.
Montane to subalpine zone, deep, aridic soils, xeromorphic shrubs, bunchgrasses, shrub cover greater than 10%, Artemsisia tridentata ssp. vaseyana
In Montana, montane sagebrush steppe occurs within the island mountain ranges of the north-central and south-central portions of the state. It dominates the landscape of southwestern Montana from valley bottoms to subalpine ridges and is found as far north as Glacier National Park.
Ecological System Distribution
Approximately 16,346 square kilometers are classified as Montane Sagebrush Steppe in the 2016 Montana Land Cover layers.
Grid on map is based on USGS 7.5 minute quadrangle map boundaries.
Montana Counties of Occurrence
BEAVERHEAD, BIG HORN, BROADWATER, CARBON, CARTER, CASCADE, CHOUTEAU, DEER LODGE, FALLON, FERGUS, FLATHEAD, GALLATIN, GOLDEN VALLEY, GRANITE, JEFFERSON, JUDITH BASIN, LAKE, LEWIS AND CLARK, LINCOLN, MADISON, MEAGHER, MINERAL, MISSOULA, MUSSELSHELL, PARK, PONDERA, POWDER RIVER, POWELL, RAVALLI, ROSEBUD, SANDERS, SILVER BOW, STILLWATER, SWEET GRASS, TETON, TREASURE, WHEATLAND, YELLOWSTONE
This ecological system occurs at montane to subalpine zones. In southwestern Montana, this system is found from 1,844 meters to 3,200 meters (6,050-10,500 feet) (Lesica et al, 2005). Much of the precipitation occurs as snow at a range of 40.3 cm (15 in.) in valley locations to upwards of 74.3 cm (35 in) along the mountain crests. Temperatures are continental with large annual and diurnal variations. In general, this system shows an affinity for mild topography, fine soils, and some source of subsurface moisture. 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 system primarily occurs on deep-soiled to stony flats, ridges, nearly flat ridgetops, and mountain slopes, but at high elevation, may be restricted to south- or west-facing slopes. In Wyoming and Montana, three tip sagebrush (Artemisia tripartita ssp. tripartita) associations are part of this system, occurring at higher elevations than the similar Inter-Mountain Basins Big Sagebrush Steppe ecological system.
In Montana, most of this system is dominated by mountain big sagebrush (Artemisia tridentata ssp. vaseyana). Mountain big sagebrush occurs in all regions, although tends to be found only on on the highest mesas. Silver sagebrush (Artemisia cana ssp. viscidula) and subalpine big sagebrush (Artemisia tridentata ssp. spiciformis) can be co-dominant on some sites. Three tip sagebrush is found only in southwestern and west-central Montana where it functions primarily as a seral component, increasing in frequency following fire. Antelope bitterbrush (Purshia tridentata) may codominate, but as a codominant is of very limited occurrence, being found primarily on intrusive volcanics in western and west-central Montana. Both subspecies of little sagebrush (Artemisia arbuscula ssp. arbuscula, and A. arbuscula ssp. longiloba) dominated shrublands occur sporadically within this system in southwestern Montana, which is the most northerly extent of their distribution. Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) dominated sites may be included in this system if they occur in the montane zone, which is most reliably indicated by the presence of Idaho fescue (F. idahoensis). These relatively uncommon sites occur above 1,280 m (4,200 feet) on the mesas of eastern Montana and the dry valleys of southwestern Montana.
Other shrubs may be present, but usually at low cover values (5-10%). Species inlcude rubber rabbitbrush (Ericameria nauseosa), and green rabbitbrush (Chrysothamnus viscidiflorus), wax currant (Ribes cereum), Woods rose (Rosa woodsii), deerbrush ceanothus (Ceanothus velutinus), snowberry (Symphoricarpos species) and serviceberry (Amelanchier alnifolia). In ares where sage has been eliminated by human activities like burning, disking or poisoning, these other shrubs may dominate the steppe system. This can be seen around Garrison and Deer Lodge, where the sage steppe ecological system contains only minimal amounts of sage.
The herbaceous layer is usually well represented. Graminoids that can be abundant include rough fescue (Festuca campestris), Idaho fescue (Festuca idahoensis), bottlebrush squirreltail (Elymus elymoides), pinegrass (Calamagrostis rubescens), needlegrass (Achnatherum species), spike fescue (Leucopoa kingii), poverty otagrass (Danthonia intermedia), western wheatgrass (Pascopyrum smithii), mountain brome (Bromus carinatus), slender wheatgrass (Elymus trachycaulus), prairie junegrass(Koeleria macrantha), bluebunch wheatgrass (Pseudoroegneria spicata), Sandberg’s bluegrass (Poa secunda), and are variety of dry, upland sedges such as threadleaf sedge (Carex filifolia) and Geyer’s sedge (Carex geyeri) (Mueggler and Stewart, 1988).
Forb diversity is frequently is moderate to high, commonly exceeding 30 species in a 400 m2 macroplot. Species may include arrowleaf balsamroot (Balsamorhiza sagittata), Indian paintbrush (Castilleja species), cinquefoil (Potentillaspecies), fleabane (Erigeron species), phlox (Phlox species), milkvetch (Astragalus species), prairie smoke (Geum triflorum), lupine (Lupinus species), buckwheat (Eriogonum species), yarrow (Achillea millefolium), rosy pussytoes (Antennaria rosea), wild strawberry (Fragaria virginiana), and western sagewort (Artemisia ludoviciana). Missouri pricklypear (Opuntia polycantha) is common on sites in southwestern Montana (Cooper et al, 1999).
Alliances and Associations
- (A.1521) Basin Big Sagebrush Shrub Herbaceous Alliance
- (A.829) Basin Big Sagebrush Shrubland Alliance
- (A.2555) Spiked Big Sagebrush Shrub Herbaceous Alliance
- (A.2550) Spiked Big Sagebrush Shrubland Alliance
- (A.1527) Wyoming Big Sagebrush Shrub Herbaceous Alliance
The natural fire regime of this ecological system has been greatly altered, 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 and others (2001) and Lesica and others (2005) have also shown that fire in big sagebrush is stand replacing, killing or removing most of the aboveground 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).
Fire and grazing can alter this system, 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). 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 sagebrushcover 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, so 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 overall, 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).
Severely burned sites may require replanting with mountain big sagebrush seedlings due to the slow recovery time within this system 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 sagebrushhas been shown to be made 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.
Polyploidy is also an important factor in adaptation. Polyploidy can influence plant fertility and vigor and polyploidy patterns are evident at the ecotonal interfaces and within populations. Polyploids are 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 Ecological System
- Details on Creation and Suggested Uses and Limitations
How Associations Were Made
We associated the use and habitat quality (common or occasional) of each of the 82 ecological systems mapped in Montana for
vertebrate animal species that regularly breed, overwinter, or migrate through the state 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, Foresman 2012, Adams 2003, and Werner et al. 2004);
- Evaluating structural characteristics and distribution of each ecological system 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 ecological system;
- Calculating the percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system 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, and species that only migrate through Montana were only evaluated for migratory habitat use.
In general, species were listed as associated with an ecological system if structural characteristics of used habitat documented in the literature were present in the ecological system or large numbers of point observations were associated with the ecological system.
However, species were not listed as associated with an ecological system if there was no support in the literature for use of structural characteristics in an ecological system, even if
point observations were associated with that system.
Common versus occasional association with an ecological system was assigned based on the degree to which the structural characteristics of an ecological system matched the preferred structural habitat characteristics for each species as represented in scientific literature.
The percentage of observations associated with each ecological system relative to the percent of Montana covered by each ecological system was also used to guide assignment of common versus occasional association.
If you have any questions or comments on species associations with ecological systems, please contact the Montana Natural Heritage Program's Senior Zoologist.
Suggested Uses and Limitations
Species associations with ecological systems 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 (this information can be requested at: http://mtnhp.org/requests/default.asp
) or systematic surveys for species and evaluations of habitat at a local site level by trained biologists.
Users of this information should be aware that the land cover data used to generate species associations is based on imagery from the late 1990s and early 2000s and was only intended to be used at broader landscape scales.
Land cover mapping accuracy is particularly problematic when the systems 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 ecological system within its known geographic range, portions of that ecological system may occur outside of the species' known geographic range.
- Adams, R.A. 2003. Bats of the Rocky Mountain West; natural history, ecology, and conservation. Boulder, CO: University Press of Colorado. 289 p.
- 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.
- 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.
- Native Species Commonly Associated with this Ecological System
- Native Species Occasionally Associated with this Ecological System
Original Concept Authors
Montana Version Authors
- Classification and Map Identifiers
Cowardin Wetland Classification:
National Vegetation Classification Standard:
||Semi-Desert (Xeromorphic Shrub and Herb Vegetation)
||Cool Semi-Desert Scrub and Grassland
||Cool Semi-Desert Scrub and Grassland
||Western North America Semi-Desert Scrub and Grassland
||Western North America Tall Sage Shrubland and Steppe
|Element Global ID
||CES304.785, Inter-Mountain Basins Montane Sagebrush Steppe
5455: Inter-Mountain Basins Montane Sagebrush Steppe
- Additional ReferencesLegend: View Online Publication
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- Cooper S.V., P. Lesica and G.M. Kudray. 2007. Post-fire Recovery of Wyoming Big Sagebrush Shrub-steppe in Central and Southeast Montana. Report to the United States Department of the Interior, Bureau of Land Management, State Office. Montana Natural Heritage Program, Helena, Montana. 16 pp. plus appendices.
- 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.
- 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. 2005. "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.
- 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.
- 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.
- Wambolt, C. L., K. S. Walhof and M. R. Frisina. 2001. Recovery of big sagebrush communities after burning in southwestern Montana. Journal of Environmental Management 61: 243-252.
- Wright, H. A., L. F. Neuenschwander, and C. M. Britton. 1979. The role and use of fire in sagebrush-grass and pinyon-juniper plant communities: A state of the art review. USDA Forest Service General Technical Report INT-58. Intermountain Forest and Range Experiment Station. Ogden, UT.