Lowland - Montane Riparian Shrubland
Global Name:
Rocky Mountain-Great Basin Lowland-Foothill Riparian Shrubland
Global Rank:
G4G5
State Rank:
S4
(see reason below)
External Links
State Rank Reason
This habitat has been detrimentally impacted by hydrological changes related to water use and dams, invasive species and grazing practices. However, these habitats are relatively common, widespread and resilient.
General Description
This National Vegetation Classification Group encompasses riparian shrublands occurring at low elevations in the valleys of western and central Montana and into the foothills and lower montane zones. It occurs on both sides of the Continental Divide. East of the Divide it is found near the island ranges extending into areas of southeastern Montana. Sites are usually below the lower treeline extending slightly into areas within the forested, montane zone. It also extends onto the plains. These communities are dominated by short to tall shrubs (up to 15ft tall) of one or more of the following species; Water Birch (Betula occidentalis), Red-osier Dogwood (Cornus sericea), Chokecherry (Prunus virginiana), American Plum (Prunus americana), Skunkbush Sumac (Rhus trilobata), Hawthorns (Crataegus spp), Sandbar Willow (Salix exigua), Pacific Willow (Salix lasiandra), Silverberry (Elaeagnus commutata), Alderleaf Buckthorn (Rhamnus alnifolia), Silver Buffaloberry (Shepherdia argentea), and/or Silver Sagebrush (Artemisia cana). These communities occur along permanent, intermittent and ephemeral streams and along major floodplains. Stands may occur along floodplains in broad, flat valleys to zones along small streams in steep-sided drainages. They can be relatively large, wide occurrences on islands in larger rivers or occur as narrow bands along small streams and on well-drained benches. They are also found in backwater channels and in other perennially wet but less scoured sites, such as floodplain swales and irrigation ditches, and they can also occur along depressional wetlands. Stands may also occur on upper benches away from active channel movement.
This group is similar to the Rocky Mountain Lower Montane-Foothill Riparian Woodland and Shrubland Ecological System.
Diagnostic Characteristics
Riparian Shrubland; Rocky Mountain and Great Plains Region; Valleys, Foothills and Lower Montane Zones; Medium to Tall Shrubs; Floodplains and Streambanks.
Typical Dominants: Water Birch (Betula occidentalis), Red-osier Dogwood (Cornus sericea), Chokecherry (Prunus virginiana), American Plum (Prunus americana), Skunkbush Sumac (Rhus trilobata), Hawthorns (Crataegus spp), Sandbar Willow (Salix exigua), Pacific Willow (Salix lasiandra), Silverberry (Elaeagnus commutata), Alderleaf Buckthorn (Rhamnus alnifolia), Silver Buffaloberry (Shepherdia argentea), Silver Sagebrush (Artemisia cana)
Similar Systems
Range
This group occurs on both sides of the Continental Divide from valleys bottoms to the lower montane zone. East of the Divide it occurs in or adjacent to the island mountain ranges and it extends along the foothills of the mountains including into the hills and lower mountains of southeastern MT.
In MT, G526 occurs within these Level III Ecoregions: 15 (Northern Rockies), 16 (Idaho Batholith), 17 (Middle Rockies), 41 (Canadian Rockies) and 43 (Northwestern Great Plains).
In Montana, G526 occurs within these Major Land Resource Areas: 43A - Northern Rocky Mountains, 43B - Central Rocky Mountains; 44A - Northern Rocky Mountain Valleys, 44B - Central Rocky Mountain Valleys, 46 - Northern and Central Rocky Mountain Foothills, 52 - Brown Glaciated Plains, 58A,B,D - Northern Rolling High Plains, and 60B Pierre Shale Plains.
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, Deer Lodge, Flathead, Gallatin, Granite, Jefferson, Lake, Lewis and Clark, Lincoln, Madison, Missoula, Park, Powell, Ravalli, Sanders, Silver Bow, Stillwater, Sweet Grass
Based on 2025 land cover layer.
Spatial Pattern
Small Patch
Environment
These communities occur along permanent, intermittent and ephemeral streams and along major floodplains. They often occur in a mosaic of shrub and tree dominated communities. Stands may occur along floodplains in broad, flat valleys to zones along small streams in steep-sided drainages. They can be relatively large, wide occurrences on islands in larger rivers or occur as narrow bands along small streams and on well-drained benches. They are also found in backwater channels and in other perennially wet but less scoured sites, such as floodplain swales and irrigation ditches, and they can also occur along depressional wetlands. Stands may also occur on upper benches away from active channel movement. Many sites occur in environments that are subject to annual or periodic flooding and scouring events. Sites dominated by Water Birch occur up to 6,000ft in elevation (Hansen etal 1995).
Vegetation
These riparian communities are dominated by short to tall shrubs (up to 15ft tall) of one or more of the following species; Water Birch (Betula occidentalis), Red-osier Dogwood (Cornus sericea), Chokecherry (Prunus virginiana), American Plum (Prunus americana), Skunkbush Sumac (Rhus trilobata), Hawthorns (Crataegus spp), Sandbar Willow (Salix exigua), Pacific Willow (Salix lasiandra), Silverberry (Elaeagnus commutata), Alderleaf Buckthorn (Rhamnus alnifolia), Silver Buffaloberry (Shepherdia argentea), and/or Silver Sagebrush (Artemisia cana). Herbaceous vegetation is often abundant and diverse and varies widely by individual communities, topographic setting and geographic area. Individual plant associations should be consulted for species commonly associated with particular communities. Non-native, herbaceous species are often common in lower elevation communities of this group. Communities dominated by several of the shrubby species, including Chokecherry, Skunkbush Sumac, Silverberry or Silver Sagebrush may also be found in upland vegetation types and NVC Groups and their presence alone cannot be used to identify this group.
This group is represented in Montana by 4 Alliances and 11 Associations within the National Vegetation Classification. These likely represent the vast majority of the variation in this group though some communities may not be represented by these types.
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.Ne D031 Western North American Temperate Freshwater Marsh, Wet Meadow and Shrubland
TP1.b1.Ne.4 M893 Western North American Montane Marsh, Wet Meadow and Shrubland
TP1.b1.Ne.4.a G526 Rocky Mountain-Great Basin Lowland-Foothill Riparian Shrubland
A2350 Artemisia cana Lowland Wet Shrubland Alliance
CEGL001460 Artemisia cana (ssp. bolanderi, ssp. viscidula) / Leymus cinereus Wet Shrubland
CEGL002988 Artemisia cana (ssp. bolanderi, ssp. viscidula) / Poa pratensis Ruderal Wet Shrubland
A3772 Betula occidentalis Wet Shrubland Alliance
CEGL001080 Betula occidentalis Wet Shrubland
CEGL001083 Betula occidentalis - Dasiphora fruticosa Wet Shrubland
CEGL001161 Betula occidentalis / Cornus sericea Wet Shrubland
A3799 Rhus trilobata - Crataegus rivularis - Forestiera pubescens Shrubland Alliance
CEGL001098 Elaeagnus commutata Wet Shrubland
CEGL001108 Prunus virginiana - (Prunus americana) Wet Shrubland
A3800 Salix exigua - Salix irrorata Shrubland Alliance
CEGL001199 Salix exigua / Agrostis stolonifera Ruderal Wet Shrubland
CEGL001203 Salix exigua / Mesic Graminoids Western Wet Shrubland
CEGL001215 Salix lucida ssp. caudata Wet Shrubland
CEGL002621 Salix lucida ssp. caudata / Rosa woodsii Wet Shrubland
CEGL005656 Salix exigua / Gravel Bar Wet Shrubland
*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
Willow-dominated shrublands, require flooding and bare gravels for reestablishment. Stands are maintained by annual flooding and hydric soils throughout the growing season. Sites are subject to temporary flooding during spring runoff. The water table is often just below the ground surface. Occurrences are found within the flood zone of rivers, on islands, sand or cobble bars, and immediate streambanks and upper benches, and occasionally on hillslope springs.
Management
Exotic trees of Russian olive (Elaeagnus angustifolia) and Saltcedar (Tamarix species) may invade some stands, particularly east of the Continental Divide.
Restoration Considerations
Information on restoration considerations for these communities is lacking at this time.
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
Amphibians
Invertebrates
- Diagnostic, Dominant, or Codominant Plant Species for this Community
Vascular Plants
Original Concept Authors
G. Kittel (2015)
Montana Version Authors
S. Mincemoyer, L. Vance, C. McIntyre, T. Luna
Version Date
12/6/2024
References
- Literature Cited AboveLegend:
View Online Publication
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.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Baker, W. L. 1989a. Macro- and micro-scale influences on riparian vegetation in western Colorado. Annals of the Association of American Geographers 79(1):65-78.
- 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.
- Web Search Engines for Articles on "Rocky Mountain-Great Basin Lowland-Foothill Riparian Shrubland"
