Mat Saltbush Shrubland
Provisional State Rank:
S4
(see reason below)
External Links
State Rank Reason
Oil and gas drilling, bentonite mining and OHV use are main threats, but they are not widespread.
General Description
This system occurs in Montana on gentle slopes, rolling plains and badlands in the extreme south-central and south-eastern portions of the state. It also occurs from Glasgow north to the Canadian border. Throughout Montana, it is associated with shale foothills and badlands where soils are saline or alkaline clays and silts with low infiltration rates. It comprises relatively pure stands of Gardner’s saltbush (Atriplex gardneri) or birdfoot sagebrush (Artemisia pedatifida). Other shrubs and sub-shrubs present may include longleaf wormwood (Artemisia longifolia), bud sagebrush (Picrothamnus desertorum), winterfat (Krascheninnikovia lanata), shortspine horsebrush (Tetradymia spinosa), shadscale saltbush (Atriplex confertifolia) or fourwing saltbush (Atriplex canescens). Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis) can occur in patches within this system on substrates that are less saline or alkaline. The herbaceous layer is usually very sparse. Harsh environmental conditions slow down community dynamics. Following disturbance, the same species, or species similar in stature or appearance, often succeed each other. Currently, exotic grass invasions are changing the dynamics of this system.
Diagnostic Characteristics
Lowland, alluvial flat, alluvial plain, plains, badland, shrubland, alkaline soil, saline substrate chemistry, calcareous, silt or clay soil texture, dwarf-shrub, Atriplex gardneri, Atriplex species
Range
This system occurs in Montana on gentle slopes and rolling plains and badlands in the extreme south-central portion of the eastern foothills of the Beartooth Range and in south-eastern portions of the state. Extensive areas also occur south of Glasgow. The broader range of this system ranges from the northern Colorado Plateau and Uinta Basin north to the plains of Wyoming; it potentially occurs in Alberta and is found in southern Saskatchewan.
Ecological System Distribution
Approximately 999 square kilometers are classified as Mat Saltbush 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
Big Horn, Blaine, Carbon, Carter, Custer, Dawson, Fallon, Garfield, Mccone, Phillips, Powder River, Richland, Rosebud, Toole, Treasure, Valley, Yellowstone
Spatial Pattern
Matrix
Environment
Mat saltbush shrublands occur on clay or silt soils that are saline and alkaline. In Montana, substrates are generally derived from marine shales.
Vegetation
This system typically supports dwarf-shrublands composed of relatively pure stands of Gardner’s saltbush (Atriplex gardneri), and in south-central Montana, birdfoot sagebrush (Artemisia pedatifida). Other dominant or codominant dwarf-shrubs may include longleaf wormwood (Artemisia longifolia) or bud sagebrush (Picrothamnus desertorum), occasionally with a mix of other low shrubs, such as winterfat (Krascheninnikovia lanata) or shortspine horsebrush (Tetradymia spinosa). Shadscale saltbush (Atriplex confertifolia) or fourwing saltbush (Atriplex canescens) may be present. Wyoming sagebrush (Artemisia tridentata ssp. wyomingensis) can occur in patches within this system on more favorable substrates that are less saline or alkaline. The herbaceous layer is typically sparse. Perennial forbs are infrequent and scattered in the undergrowth. Common species include smooth woody aster (Xylorhiza glabriuscula) and scarlet globe mallow (Sphaeralcea coccinea). Annual species of saltbush (Atriplex), povertyweed (Monolepis), goosefoot (Chenopodium) and seepweed (Suadea) are frequently present. Perennial grasses have the highest herbaceous cover. Indian ricegrass (Achnatherum hymenoides), blue grama (Bouteloua gracilis), squirrel tail (Elymus elymoides), thickspikewheatgrass (Elymus lanceolatus ssp. lanceolatus), western wheatgrass (Pascopyrum smithii), Sandberg’s bluegrass (Poa secunda), or alkali sacaton (Sporobolus airoides) are the most common species found in this system. In less saline areas, there may be inclusions of grasslands dominated by needle and thread (Hesperostipa comata), saline wild rye (Leymus salinus), western wheatgrass, or bluebunch wheatgrass (Pseudoroegneria spicata). There may also be inclusions of non-saline, gravelly barrens or rock outcrops dominated by cushion plants such as Hooker’s sandwort (Arenaria hookeri) and Hood’s phlox (Phlox hoodii) without dwarf-shrubs. Under disturbance, cheatgrass (Bromus tectorum) or other annual bromes can become abundant.
Adapted from US National Vegetation Classification
A1110 Atriplex gardneri Low Scrub Alliance
CEGL001438 Atriplex gardneri Dwarf-shrubland
CEGL001439 Atriplex gardneri - Picrothamnus desertorum Dwarf-shrubland
CEGL001440 Atriplex gardneri - Artemisia tridentata Dwarf-shrubland
CEGL001443 Atriplex gardneri - Monolepis nuttalliana Dwarf-shrubland
CEGL001444 Atriplex gardneri - Achnatherum hymenoides Dwarf-shrubland
CEGL001445 Atriplex gardneri - Pascopyrum smithii Dwarf-shrubland
A1127 Artemisia pedatifida Low Scrub Alliance
CEGL001526 Artemisia pedatifida - Festuca idahoensis Shrubland
CEGL001527 Artemisia pedatifida - 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.5 M093 Great Basin Saltbush Scrub
3.B.1.Ne.5.a G301 Intermountain Dwarf Saltbush-Sagebrush Scrub
A1110 Atriplex gardneri Low Scrub Alliance Gardner's Saltbush Low Scrub
CEGL001438 Atriplex gardneri Dwarf-shrubland
CEGL001439 Atriplex gardneri - Picrothamnus desertorum Dwarf-shrubland
CEGL001440 Atriplex gardneri - Artemisia tridentata Dwarf-shrubland
CEGL001443 Atriplex gardneri - Monolepis nuttalliana Dwarf-shrubland
CEGL001444 Atriplex gardneri - Achnatherum hymenoides Dwarf-shrubland
CEGL001445 Atriplex gardneri - Pascopyrum smithii Dwarf-shrubland
A1127 Artemisia pedatifida Low Scrub Alliance Birdfoot Sagebrush Low Scrub
CEGL001526 Artemisia pedatifida - Festuca idahoensis Shrubland
CEGL001527 Artemisia pedatifida - Pseudoroegneria spicata 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
The harsh environmental conditions of these systems slow down community dynamics. Following disturbance, the same species or species similar in stature or appearance often succeed each other. Fire frequency was historically very low in this system. Heavy sheep grazing practices can significantly impact vigor and cover of the principal shrub species, leading to an increase of cheatgrass and other exotic annual forbs. Sites infested with cheatgrass are changing the dynamics of this system by increasing fire potential, severity and spread.
Management
Heavy grazing practice, particularly sheep grazing, can result in the loss of the most common perennial grasses in this system and lead to an abundance cheatgrass and other annual bromes and forbs.
Restoration Considerations
Natural regeneration of saltbush species and associated species occurs where old plants existed in the interspaces, due to accumulated organic matter and nutrients and more favorable moisture (West 1982). Shrub seedlings should be planted in these microsites improve survival rates.
Gardner’s saltbush has an extensive, highly branched root system and tolerates poor site conditions. It has been used to stabilize soils and to reclaim disturbed sites (Clarke and others 1943; Carlson and others 1984). It was one of only two species to establish on coal mine spoils in Wyoming (Frischknecht and Ferguson 1984).
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
Vascular Plants
- Native Species Occasionally Associated with this Ecological System
Mammals
Birds
Reptiles
Vascular Plants
Original Concept Authors
Natureserve Western Ecology Group
Montana Version Authors
T. Luna
Version Date
1/1/2017
References
- Classification and Map Identifiers
Cowardin Wetland Classification:
Not applicable
NatureServe Identifiers:
| Element Global ID |
28621 |
| System Code |
CES304.783, Inter-Mountain Basins Mat Saltbush Shrubland |
ReGAP:
5203: Inter-Mountain Basins Mat Saltbush Shrubland
- Additional ReferencesLegend:
View Online Publication
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