Intermountain Alkaline - Saline Grassland and Meadow
Global Name:
North American Desert Alkaline-Saline Marsh & Playa
Global Rank:
G4G5
State Rank:
S3S4
(see reason below)
External Links
State Rank Reason
These uncommon, alkaline and saline, mesic grasslands are limited primarily to portions of southern MT. Threats and trends are poorly documented, though potential impacts from grazing, invasive species, climate change and water use may have negatively impacted or may impact these sites in the future.
General Description
This National Vegetation Classification Group is a minor type in MT and contains alkaline and/or saline marshes and wetlands within the Intermountain Region which includes the Bighorn Basin and the Intermountain valleys of southwest Montana. These are intermittently, seasonally or semi-permanently flooded, usually retaining water into the growing season. They are sparsely to densely-vegetated by herbaceous species tolerant of alkaline and/or saline conditions. Typical species include Saltgrass (Distichlis spicata), Alkaligrasses (Puccinellia spp), Foxtail Barley (Hordeum jubatum), Alkali Muhly (Muhlenbergia asperifolia), Alkali Cordgrass (Spartina gracilis), Alkali Sacaton (Sporobolus airoides), Great Basin Wildrye (Elymus cinereus), Beaked Spikerush (Eleocharis rostellata), and Saltmarsh Bulrush (Bolboschoenus maritimus). The presence and abundance of various species and communities depends in large part on the local hydrology and the mix of microhabitats present. Sites occur predominantly along the valley bottoms in closed drainages and/or within depressions, occasionally they can be associated with hot and cold springs.
This group has no similar Ecological System for the Intermountain Region within Montana.
Diagnostic Characteristics
Saline Wetlands; Marsh, Wet Meadow; Herbaceous Dominated; Intermountain Region; Seasonally or Vernally Saturated; High Clay Contents.
Typical Dominants: Saltgrass (Distichlis spicata), Alkaligrass (Puccinellia spp), Foxtail Barley (Hordeum jubatum), Alkali Muhly (Muhlenbergia asperifolia), Alkali Cordgrass (Spartina gracilis), Alkali Sacaton (Sporobolus airoides), Great Basin Wildrye (Elymus cinereus), Beaked Spikerush (Eleocharis rostellata), Saltmarsh Bulrush (Bolboschoenus maritimus)
Similar Systems
Range
This group occurs primarily in the Intermountain valleys of southwest Montana and in the Bighorn Basin in Carbon County. Minor occurrences extend as far north as the Helena Valley along the Missouri River Drainage. In south-central Montana it is found primarily in the Bighorn Basin of Carbon County and possibly in the vicinity of Gardiner in southern Park County. A geographic outlier with vegetation communities that are likely similar to and best included in this group occurs in the area near the Little Bitterroot River and the Sullivan Creek drainages from near Hot Springs to north of Niarada.
In Montana, G538 occurs in Level IV Ecoregions: 15b (Camas Valley), 17aa (Dry Intermontane Sagebrush Valleys), 17ac (Big Hole), 17 ak (Deer Lodge-Philipsburg-Avon Grassy Intermontane Hills and Valleys), 17w (Townsend Basin) and 18b (Bighorn Basin).
In Montana, G538 occurs or potentially occurs within these Major Land Resource Areas: 32 - Northern Intermountain Desertic Basins, 44A - Northern Rocky Mountain Valleys, 44B - Central Rocky Mountain Valleys, and valley bottoms within 43B - Central Rocky Mountains
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
Carbon
Based on 2025 land cover layer.
Spatial Pattern
Small Patch
Environment
This minor type in MT contains alkaline and/or saline marshes and wetlands within the Intermountain Region which includes the Bighorn Basin and the Intermountain valleys of southwest Montana. These are intermittently, seasonally or semi-permanently flooded, usually retaining water into the growing season. They are sparsely to densely vegetated by herbaceous species tolerant of alkaline and/or saline conditions. Sites occur predominantly along the valley bottoms in closed drainages and/or minor within depressions or flats, occasionally they can be associated with hot and cold springs. Rangewide this group is dominated by playas, though we have small areas that are similar to playas in the Great Basin we do not have large, playas typical of the closed basins in that region.
Vegetation
Communities in this group are sparsely to densely-vegetated by herbaceous species tolerant of alkaline and/or saline conditions. Typical species include Saltgrass (Distichlis spicata), Alkaligrass (Puccinellia spp), Foxtail Barley (Hordeum jubatum), Alkali Muhly (Muhlenbergia asperifolia), Alkali Cordgrass (Spartina gracilis), Alkali Sacaton (Sporobolus airoides), Great Basin Wildrye (Elymus cinereus), Beaked Spikerush (Eleocharis rostellata), and Saltmarsh Bulrush (Bolboschoenus maritimus). The presence and abundance of various species and communities depends in large part on the local hydrology, including the soil chemistry and length of soil saturation during the growing season as well as the mix of microhabitats present.
In Montana, this group is represented by 4 Alliances and 8 Associations within the National Vegetation Classification, which likely covers the range of vegetation communities occurring in the group and within the state.
National Vegetation Classification
Download the complete NVC hierarchy for Montana
TP1 B08 Palustrine Wetland
TP1.b S70 Emergent Open Wetland
TP1.b3 F139 Inland Salt Marsh
TP1.b3.Nb D036 Western North American Inland Saline Marsh
TP1.b3.Nb.1 M082 North American Desert Alkali-Saline Marsh, Playa and Shrubland
TP1.b3.Nb.1.a G538 Desert Alkaline-Saline Marsh and Playa
A1329 Leymus cinereus - Leymus triticoides Alkaline Wet Meadow Alliance
CEGL001479 Leymus cinereus Alkaline Wet Meadow
A1332 Distichlis spicata - Frankenia salina - Juncus cooperi Wet Meadow Alliance
CEGL001770 Distichlis spicata Alkaline Wet Meadow
CEGL005285 Hordeum jubatum Great Basin Wet Meadow
A1334 Sporobolus airoides - Muhlenbergia asperifolia - Spartina gracilis Alkaline Wet Meadow Alliance
CEGL001588 Spartina gracilis Alkaline Wet Meadow
CEGL001799 Puccinellia nuttalliana Salt Marsh
A3930 Eleocharis palustris - Eleocharis rostellata Alkaline-Saline Marsh Alliance
CEGL001843 Bolboschoenus maritimus Marsh
CEGL003428 Eleocharis rostellata Marsh
*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
These areas are lined with clay soils, which collect and hold water from rainfall and runoff events. Water evaporates, leaving high salt concentrations in the soils. The presence and abundance of standing water can fluctuate widely from year to year based on precipitation amounts. In areas with standing water or during flood years, some salt-tolerant marsh plant species may grow, such as Cattails (Typha spp.) or Bulrush (Scirpus and/or Schoenoplectus spp.) (Knight 1994).
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
Invertebrates
- Diagnostic, Dominant, or Codominant Plant Species for this Community
Vascular Plants
- Other Native Species Commonly Associated with this Community
Vascular Plants
Original Concept Authors
G. Kittel (2015)
Montana Version Authors
S. Mincemoyer
Version Date
12/5/2024
References
- Literature Cited AboveLegend:
View Online Publication
Knight, D. H. 1994. Mountains and plains: Ecology of Wyoming landscapes. Yale University Press, New Haven, MA. 338 pp.
- Additional ReferencesLegend:
View Online Publication
Do you know of a citation we're missing?
Hansen, P. L., R. D. Pfister, K. Boggs, B. J. Cook, J. Joy, and D. K. Hinckley. 1995. Classification and management of Montana's riparian and wetland sites. Montana Forest and Conservation Experiment Station, School of Forestry, University of Montana, Miscellaneous Publication No. 54. 646 pp. + posters.
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