Arid West Freshwater Marsh and Wet Meadow
Global Name:
Arid West Interior Freshwater Marsh & Wet Meadow
Global Rank:
G4G5
State Rank:
S3S4
(see reason below)
External Links
State Rank Reason
These low elevation wet meadows and marsh habitats are widespread but uncommon. They have experienced a decrease in condition and extent, and they continue to be negatively impacted by invasive species, grazing, development and by increases in temperatures and drought.
General Description
This National Vegetation Classification Group is composed of herbaceous wetlands. These wetlands occur mostly as small patches on the landscapes and are largely confined to limited areas in suitable floodplain or basin topography. They are seasonally, semi-permanently or permanently flooded habitats. Water is at or above the soil surface for most of the growing season. This group includes shallow, freshwater to slightly brackish waters found in bottomlands along drainages, in river floodplain depressions, along side channels, below seeps and at the margins of lakes, ponds, stock ponds, ditches and slow-moving streams. A consistent source of freshwater is essential to the function of these communities. Vegetation communities include those dominated by Cattails (Typha sp), Bulrushes (Schoenoplectus spp, Scirpus spp), Sedges (Carex spp), Rushes (Juncus spp), Spikerushes (Eleocharis spp). Soils are muck, mineral, or muck over mineral soil, and water is high in nutrients. This wetland group occurs on both sides of the Continental Divide excluding areas of the Great Plains and ranges from valley bottoms to the montane zone.
This group encompasses portions of the Emergent Marsh Ecological System.
Diagnostic Characteristics
Wetlands; Marsh and Wet Meadow; Herbaceous Dominated; Rocky Mountain and Intermountain Region; Valley Bottoms to the Montane Zone; Seasonally, Vernally or Permanently Saturated; Hydric Soils
Typical Dominants: Cattails (Typha sp), Bulrushes (Schoenoplectus spp, Scirpus spp) Sedges (Carex spp), Rushes (Juncus spp), Spikerushes (Eleocharis spp)
Similar Systems
Range
This wetland group occurs on both sides of the Continental Divide from valley bottoms to the montane zone. It potentially occurs in or near all of the island ranges east of the Divide including the foothills of the Rocky Mountain Front and south to the Bighorn Mountains. Similar communities in the Great Plains are included in G325.
In MT, G531 occurs primarily within Level III Ecoregions: 15 (Northern Rockies), 16 (Idaho Batholith), 17 (Middle Rockies), 18 (Wyoming Basin) and 41 (Canadian Rockies) and extending into the western portions of 42 (Northwestern Glaciated Plains) and 43 (Northwestern Great Plains).
In Montana, G531 occurs primarily within these Major Land Resource Areas: 32 - Northern Intermountain Desertic Basins, 43A - Northern Rocky Mountains, 43B - Central Rocky Mountains, and in limited extent within 44A - Northern Rocky Mountain Valleys, 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, Broadwater, Carbon, Cascade, Deer Lodge, Fergus, Flathead, Gallatin, Glacier, Granite, Jefferson, Judith Basin, Lake, Lewis and Clark, Lincoln, Madison, Meagher, Mineral, Missoula, Park, Pondera, Powell, Ravalli, Sanders, Silver Bow, Stillwater, Sweet Grass, Teton, Wheatland, Yellowstone
Based on 2025 land cover layer.
Spatial Pattern
Small Patch
Environment
These wetlands occur mostly as small patches on the landscape and are largely confined to limited areas in suitable floodplain or basin topography. They are seasonally, semi-permanently or permanently flooded habitats. Water is at or above the soil surface for most of the growing season and includes shallow freshwater to slightly brackish waters found in bottomlands along drainages, in river floodplain depressions, along side channels, below seeps and at the margins of lakes, ponds, stock ponds, ditches and slow-moving streams. Sites can have water levels from completely drained (exposed soil) to approximately 1.5 meters deep but are usually less than 1 meter. Water levels can vary by up to 1 m during the year. A consistent source of freshwater is essential to the function of these communities. Soils are muck, mineral, or muck over mineral soil, and water is high in nutrients.
Vegetation
Vegetation in marshy habitats is often patchy or zonal and is driven by the depth of standing water or lack thereof across the growing season. Communities dominated by Cattails (Typha sp), Bulrushes (Schoenoplectus spp, Scirpus spp), Sedges (Carex spp), Rushes (Juncus spp), and Spikerushes (Eleocharis spp) are the most common. Species richness can vary considerably among individual marshes and wetlands and is influenced in part by adjacent land use. Heights of common vegetation types mostly vary from 0.5 meter to 2 meters tall. Vegetation communities occurring in marshes are representative of their hydroperiod; some basins dry to bare soil after seasonal flooding, while others will have a variety of wetland types in a zoned pattern depending on seasonal water table depths and salt concentrations (Kudray and Cooper, 2006). In semi-permanent marshes, typical communities may include annuals in the drawdown zone near the upland edge, with sedges (Carex species) down gradient, and Broadleaf Cattail (Typha latifolia) and Hardstem Bulrush (Schoenoplectus acutus) located in the deeper, central portion of the marsh. Beyond the emergent vegetation, floating-leaved hydrophytes may be present in wetter sites with longer inundation periods, including Water Lilies (Nymphaea species), Yellow Pondlily (Nuphar species), Water Buttercup (Ranunculus aquatilis) and Pondweed (Potamogeton species). Other floating species may be present in shallow water, such as Duckweed (Lemna species), and submergents such as Common Hornwort (Ceratophyllum demersum), Horned Pondweed (Zannichellia palustris), Mare’s Tail (Hippuris vulgaris) and Common Water-milfoil (Myriophyllum sibiricum).
Non-native species, including Reed Canarygrass (Phalaris arundinacea), Yellow Flag Iris (Iris pseudacorus) and Purple Loosestrife (Lythrum salicaria) may invade these habitats, displacing native species.
In Montana, this group is represented by vegetation communities classified into 3 Alliances and 5 Associations within the National Vegetation Classification. Additional vegetation types likely occur, and further review is needed.
National Vegetation Classification
Download the complete NVC hierarchy for Montana
TP1 B08 Palustrine Wetland
TP1.b S70 Emergent Open Wetland
TP1.b1 F137 Marsh, Wet Meadow and Shrub Wetland
TP1.b1.Nd D032 North American Desert and Arid West Freshwater Marsh and Bosque
TP1.b1.Nd.2 M888 Arid West Interior Freshwater Marsh and Wet Meadow
TP1.b1.Nd.2.a G531 Arid West Interior Freshwater Marsh and Wet Meadow
A3891 Carex praegracilis - Eleocharis palustris - Hordeum jubatum Wet Meadow Alliance
CEGL002660 Carex praegracilis Wet Meadow
A3895 Schoenoplectus americanus - Schoenoplectus pungens - Eleocharis palustris Marsh Alliance
CEGL001587 Schoenoplectus pungens Marsh
CEGL001841 Schoenoplectus americanus Western Marsh
A3896 Typha domingensis - Typha latifolia - Schoenoplectus acutus Western Marsh Alliance
CEGL001840 Schoenoplectus acutus Marsh
CEGL002623 Schoenoplectus tabernaemontani Temperate Marsh
CEGL008734 Typha latifolia Western 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
Drought cycles, annual fluctuations in precipitation and local changes in hydrology directly affect these sites and will result in changes to the vegetation patterns within these marsh and wetland habitats.
Management
Adjacent land use practices should be considered as they may detrimentally impact these communities through nutrient and pollution runoff.
Restoration Considerations
In marsh habitats where water has been drained or altered, the original hydrology of the system must be restored. If water levels are restored, re-growth and re-colonization from dormant rhizomatous root systems of common marsh species often can occur within a few years. Cattle grazing must be eliminated or controlled to allow regrowth, recolonization and resprouting from existing root systems. Many of the characteristic species found in marsh habitats are rhizomatous, thus exhibiting excellent erosion control properties. In some cases, if hydric soils are heavily altered due to pugging or compaction, addition of organic material may be needed to facilitate vegetation recolonization.
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
Amphibians
Original Concept Authors
M.E. Hall, G. Kittel and J. Christy (2015)
Montana Version Authors
S. Mincemoyer, T. Luna, C. McIntyre, L. Vance
Version Date
12/6/2024
References
- Additional ReferencesLegend:
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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.- Hansen, P. L., S. W. Chadde, and R. D. Pfister. 1988b. Riparian dominance types of Montana. University of Montana Miscellaneous Publication 49. Montana Forest and Conservation Experiment Station, Missoula. 411 pp.
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