Low Sagebrush Shrubland
Provisional State Rank:
S4
(see reason below)
External Links
State Rank Reason
The area of occupancy may be overestimated in ReGAP, as it is difficult to distinguish this specific ecological system from other sage types with a low-growth habit. However, it appears to be reasonably widespread.
General Description
This system is composed of dwarf sagebrush shrubland and shrub-steppe that forms matrix vegetation and large patches on the margins of high-elevation basins. It occurs in southwest and south-central Montana on sites that are gently to moderately sloping, particularly on dry, windswept hills and ridges that may be oriented to any aspect. Elevation ranges from 1,143 meters (3,750 feet) in the Pryor Mountains and 1,219 meters (4,000 feet in) the Canyon Ferry area and up to 2,195 meters (7,200 feet) in southwestern Montana. Typical sites are gently rolling hills and long, gently sloping pediments and fans. These sites are very windy and have shallow, often rocky soils. Rock and gravel cover much of the unvegetated ground surface, with some bare ground and litter. In Montana, soils are typically silts or clays, shallow to moderately deep, and derived from limestone parent material. The distinguishing feature of this system is a short-shrub stratum in which dwarf-shrubs (<30 centimeters tall) contribute at least two-thirds of the woody canopy. Black sage (Artemisia nova) is usually dominant in this system. In southwestern Montana, little sagebrush (Artemisia arbuscula ssp. arbuscula and ssp. longiloba) is dominant, found on restrictive clay soils that inhibit root depth and create a perched water table. Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) can be present within this system.The herbaceous component includes both rhizomatous and bunchgrasses, cushion plants, and other low-growing forbs. This system is characterized as steppe vegetation, occurring in areas where precipitation is limiting for tree growth.
Diagnostic Characteristics
Steppe,shrub dominated, lowland and foothill elevations, hills, sideslopes, ridge/summit/upperslope, silt and clay soil texture, shallow aridic soils, low (less than 30 cm tall) xeromorphic shrub heights, low-growing Artemisia species
Similar Systems
Range
This system occurs in southwest and central Montana. At the northern end of its range, it occurs on the north flank on the Elkhorn Mountains near Helena. It is well represented in the Tobacco Root and Ruby Mountains, and occurs in other scattered locations in southwestern Montana. It is found on the eastern flanks of the Beartooth range on outwash fans and lower slopes, and the southerly-facing flank of the Pryor Mountains.
Ecological System Distribution
Approximately 101 square kilometers are classified as Low Sagebrush Shrubland in the 2017 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, Cascade, Deer Lodge, Flathead, Gallatin, Granite, Jefferson, Judith Basin, Lewis and Clark, Lincoln, Madison, Meagher, Mineral, Missoula, Park, Powder River, Powell, Ravalli, Sanders, Silver Bow, Stillwater, Sweet Grass, Wheatland, Yellowstone
Spatial Pattern
Large or Small Patch
Environment
This system occurs in southwest and south-central Montana on sites that are gently to moderately sloping, especially on dry, windswept hills and ridges that may be oriented to any aspect. Elevation ranges from to 1,143 meters (3,750 feet) in the Pryor Mountains and 1,219 meters (4,000 feet in) the Canyon Ferry area and up to 2,195 meters (7,200 feet) in southwestern Montana. Soils are shallow, gravelly and are often high in calcium carbonate. Rock and gravel cover much of the unvegetated ground surface, with some bare ground and litter. In Montana, soils are typically shallow to moderately deep, rapidly drained and derived from limestone. This system also occurs on granitic intrusions with overlying calcareous substrates. Soils are usually silts or clays. In southwestern Montana, soils are clays with a restrictive layer that inhibits root growth and creates a perched water table.
Vegetation
This system is characterized as steppe vegetation, occurring in areas where precipitation is limiting for tree growth. Vegetation is characterized by a low-shrub canopy dominated by black sage. In Montana, the black sage dominated steppe system grades into the Rocky Mountain Limber Pine-Juniper Woodland system in central and southern Montana.
Other shrubs are generally present, although with very low cover, including green rabbitbrush (Chrysothamnus viscidiflorus), little sagebrush (Artemisia arbuscula ssp. longiloba), spiny hopsage (Grayia spinosa), snowberry (Symphoricarpos longiflorus), and broom snakeweed (Gutierrezia sarothrae). In southwestern Montana, little sagebrush is the dominant low shrub. Wyoming big sagebrush can be present within this system on some occurrences. In these cases, this system can grade into or be interpreted as Big Sagebrush Shrubland.
Graminoids usually dominate the diverse herbaceous layer, with bluebunch wheatgrass (Pseudoroegneria spicata) being the most common. Other species present can include Indian ricegrass (Achnatherum hymenoides), threadleaf sedge (Carex filifolia), slender wheatgrass (Elymus trachycaulus), needle and thread (Hesperostipa comata), prairie junegrass (Koeleria macrantha), western wheatgrass (Pascopyrum smithii) and Sandberg’s bluegrass (Poa secunda). The invasive cheatgrass (Bromus tectorum) frequently invades this system. Forb cover is generally low and includes cushion species and other low forbs such as Hood’s phlox (Phlox hoodii), tapertip hawksbeard (Crepis acuminata), milkvetch (Astragalus species), stemless mock goldenweed (Stenotus acaulis), spreading phlox (Phlox diffusa), boreal sagewort (Artemisia frigida), and mariposa lily (Calochortus species).
Adapted from US National Vegetation Classification
A3182 Artemisia tridentata ssp. Wyomingensis Mesic Steppe & Shrubland Alliance
CEGL001049 Artemisia tridentata ssp. wyomingensis - Poa secunda Shrubland
A3221 Artemisia arbuscula ssp. Longiloba Steppe & Shrubland Alliance
CEGL001416 Artemisia arbuscula ssp. longiloba - Pseudoroegneria spicata Shrub Grassland
CEGL002585 Artemisia arbuscula ssp. longiloba - Elymus lanceolatus Shrubland
A3222 Artemisia nova Steppe & Shrubland Alliance
CEGL001424 Artemisia nova - Pseudoroegneria spicata Shrubland
3 C03 Desert and Semi-Desert
3.B S11 Cool Semi-Desert Scrub and Grassland
3.B.1 F033 Cool Semi-Desert Scrub and Grassland
3.B.1.Ne D040 Western North American Cool Semi-Desert Scrub and Grassland
3.B.1.Ne.2 M170 Great Basin-Intermountain Dwarf Sagebrush Steppe & Shrubland
3.B.1.Ne.2.b G308 Intermountain Low & Black Sagebrush Steppe & Shrubland
A3221 Artemisia arbuscula ssp. Longiloba Steppe & Shrubland Alliance Alkali Sagebrush Steppe & Shrubland
CEGL001416 Artemisia arbuscula ssp. longiloba - Pseudoroegneria spicata Shrub Grassland
CEGL002585 Artemisia arbuscula ssp. longiloba - Elymus lanceolatus Shrubland
A3222 Artemisia nova Steppe & Shrubland Alliance Black Sagebrush Steppe & Shrubland
CEGL001424 Artemisia nova - Pseudoroegneria spicata Shrubland
3.B.1.Ne.3 M169 Great Basin-Intermountain Tall Sagebrush Steppe & Shrubland
3.B.1.Ne.3.b G302 Intermountain Tall Sagebrush Steppe & Shrubland
A3182 Artemisia tridentata ssp. Wyomingensis Mesic Steppe & Shrubland Alliance Wyoming Big Sagebrush Mesic Steppe & Shrubland
CEGL001049 Artemisia tridentata ssp. wyomingensis - Poa secunda Shrubland
*Disclaimer: Alliances and Associations have not yet been finalized in the National Vegetation Classification (NVC) standard.
A complete version of the NVC for Montana can be found
here.
Dynamic Processes
This association usually occurs in a patchy mosaic with other types of sagebrush shrublands. Black sage and little sagebrush shrublands generally occur on the driest, most windswept sites with the shallowest soils relative to shrublands dominated by other sagebrush species. This species is easily killed by fire at all intensities, and when exposed to fire, plants do not re-sprout (Wright et al, 1979). Heavy grazing practices also lead to a decrease in associated grasses and an increase in the spread of cheatgrass. Sites invaded by cheatgrass are changing the dynamics of this system by increasing fire potential, severity and spread.
Management
Excessive grazing can result in the demise of the most common perennial grasses in this system and lead to an abundance of cheatgrass.
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:
mtnhp.org/requests) 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.
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.
- 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
Mammals
Birds
Reptiles
Amphibians
Invertebrates
Vascular Plants
- Native Species Occasionally Associated with this Ecological System
Mammals
Birds
Reptiles
Amphibians
Original Concept Authors
Natureserve Western Ecology Group
Montana Version Authors
L.K. Vance, T. Luna
Version Date
1/1/2017
References
- Classification and Map Identifiers
Cowardin Wetland Classification:
Not applicable
NatureServe Identifiers:
| Element Global ID |
28630 |
| System Code |
CES304.794, Wyoming Basins Dwarf Sagebrush Shrubland and Steppe |
ReGAP:
5209: Wyoming Basins Dwarf Sagebrush Shrubland and Steppe
- Additional ReferencesLegend:
View Online Publication
Do you know of a citation we're missing?- Aguirre, Lucrecia, and Douglas A. Johnson. 1991. "Influence of Temperature and Cheatgrass Competition on Seedling Development of Two Bunchgrasses". Journal of Range Management. 44 (4): 347-354.
- Harris, G.A. 1967. Some competitive relationships between Agropyron spicatum and Bromus tectorum. Ecological Monographs 37:89-111.
- 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.
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.
