Provisional State Rank
(see reason below)
State Rank Reason
Climate change is the major threat over the long term.
This system occurs above upper treeline throughout the Rocky Mountains and east into the mountain island ranges of central Montana. Elevation ranges from as low as 1,981 meters (6,500 feet) in northwestern Montana to 3,200 meters (10,500 feet) in southern Montana. The climate is very cold, with heavy snow accumulation and a very short growing season (60 to 90 days). This system occurs on level or concave glacial topography with late-lying snow and subirrigation from surrounding slopes. It can occur on all aspects, but is most common on north and east facing aspects. These sites are characterized as snow bed communities, where snow persists until mid or late summer, or occasionally, until fall. Soil temperatures remain colder than in the surrounding alpine meadows throughout the growing season. Soils are moist but well-drained, strongly acidic, and often with substantial peat layers. These dwarf shrublands are characterized by a semi-continuous layer of ericaceous dwarf-shrubs or dwarf willows which form a heath type ground cover less than 0.5 m (1.6 foot) in height. The ericaceous shrub community is dominated by western moss heather (Cassiope mertensiana), white arctic mountainheather (Cassiope tetragona), yellow mountain heath (Phyllodoce glanduliflora), pink mountain heath (Phyllodoce empetrifomis), and alpine bog laurel (Kalmia microphylla). Grouse whortleberry (Vaccinium scoparium), bilberry (Vaccinium myrtillus) or mountain huckleberry (Vaccinium membranaceum) are often found within the heath shrublands in northwestern Montana. The willow community forms localized thickets on level areas or on the perimeter of depressional areas and can be dominated by either mat forming or dwarf -shrub alpine willows (Salix spp.). The herbaceous understory is composed of a diversity of alpine sedges (Carex ssp.), rushes (Juncus spp.), woodrushes (Luzula spp.), alpine grasses and forbs.
Alpine, patterned ground, glaciated, udic, acidic soils, alpine slopes, dwarf shrubland, very long disturbance interval
This system occurs above upper treeline throughout the Rocky Mountain ranges, and east into the mountain island ranges of central and south-central Montana. Elsewhere, this system ranges from the Canadian Rocky Mountains of British Columbia and Alberta south to northern New Mexico and the mountains of Utah and Nevada. It is found west from Montana throughout the mountains of Idaho, Oregon and the Cascade and Olympic Mountains of Washington.
Ecological System Distribution
Approximately 278 square kilometers are classified as Alpine Dwarf-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, Carbon, Deer Lodge, Flathead, Gallatin, Glacier, Granite, Lewis and Clark, Lincoln, Madison, Missoula, Park, Pondera, Powell, Ravalli, Stillwater, Sweet Grass, Teton
This system is found in areas of level or concave glacial topography with late-lying snow and subirrigation from surrounding alpine slopes. Elevation ranges from as low as 1,981 meters (6,500 feet) in northwestern Montana to 3,200 meters (10,500 feet) in southwestern Montana. Sites are characterized as snow bed communities, which form in concave, depressional areas that retain snow until mid to late summer. It can occur on all aspects but is most common on north and east facing aspects. Soil temperatures remain colder than in the surrounding alpine meadow throughout the growing season. Soils have become relatively stabilized in these sites, and are moist but well-drained, strongly acidic, and often with substantial peat layers. Vegetation in these areas is controlled by snow retention, wind desiccation, and a short growing season, usually only 60 to 90 days.
This system is composed of dwarf shrublands of ericaceous dwarf-shrubs or dwarf, alpine willows forming a low shrubland ground cover less than 0.5 meters (1.6 feet) in height. The ericaceous shrub community is dominated by western moss heather, white arctic mountainheather, yellow mountain heath, pink mountain, and alpine bog laurel. Grouse whortleberry, bilberry, or mountain huckleberry are often found within the heath shrublands, especially in northwestern Montana. Common graminoids and forbs include showy sedge (Carex spectabilis), shortstalk sedge (Carex podocarpa), Rocky Mountain sedge (Carex scopulorum), Hitchcock’s woodrush (Luzula glabrata var. hitchcockii) and Piper’s woodrush (Luzula piperi). Forbs such as alpine pussytoes (Antennaria species), arnica (Arnica species), Indian paintbrush (Castilleja species), glacier lily (Erythronium grandiflorum), alpine Saint John’s wort (Hypericum formosum), viviparous bistort (Polygonum viviparum) and Rocky Mountain groundsel (Packera cymbalarioides) are found within the heath-dominated shrubland.
Willow dominated communities form localized thickets on more level areas or around the perimeter of depressional areas. These depressional areas can have greater peat development. Dwarf, mat-forming species such as arctic willow (Salix arctica) and snow willow (Salix reticulata) are common associates. Other willow bed communities composed of shrubs that are less than .5 metrs (1.6 feet) tall include undergreen willow (Salix commutata), grayleaf willow (Salix glauca), plane leaf willow (Salix planifolia), and, in areas underlain by calcareous parent material, shortfruit willow (Salix brachycarpa) (Bamberg and Major, 1968). Sedges and rushes dominate in the depressional or level areas and are usually the last to emerge after snowmelt. These areas are species poor and are dominated by black sedge (Carex nigricans), Drummond’s rush (Juncus drummondii) and tufted hairgrass (Deschampsia cespitosa) or purple mountain hairgrass (Vahlodea atropurpurea). Sibbaldia (Sibbaldia procumbens), Ross’ avens (Geum rossii), and marsh marigold (Caltha leptosepala) often occur in openings in the peat (Cooper et al., 1997). Alpine dwarf shrublands occur as distinct patch types within Rocky Mountain Alpine Fell-Fields or adjacent to Rocky Mountain Alpine-Montane Wet Meadows or at the upper elevational limit of Rocky Mountain Subalpine Woodlands and Parklands.
National Vegetation Classification Switch to Full NVC View
Adapted from US National Vegetation Classification
A3176 Salix arctica - Salix nivalis - Salix reticulata Alpine Dwarf-shrubland Alliance
CEGL001431 Salix arctica / (Salix petrophila, Salix nivalis) - Polygonum bistortoides Dwarf-shrubland
CEGL001435 Salix reticulata - Caltha leptosepala Dwarf-shrubland
CEGL005878 Salix arctica - Carex nigricans Dwarf-shrubland
A3177 Phyllodoce empetriformis - Phyllodoce glanduliflora / Sibbaldia procumbens Alpine Snowbed Dwarf-shrubland Alliance
CEGL001405 Phyllodoce empetriformis - Antennaria lanata Dwarf-shrubland
CEGL005877 Phyllodoce glanduliflora - Sibbaldia procumbens Dwarf-shrubland
A3178 Dryas integrifolia - Dryas octopetala - Arctostaphylos uva-ursi Rocky Mountain Fell-field Dwarf-shrubland Alliance
CEGL001890 Dryas integrifolia / Carex spp. Alpine Dwarf-shrub Meadow
CEGL001894 Dryas octopetala / Polygonum viviparum Alpine Dwarf-shrub Meadow
A3770 Salix wolfii - Salix brachycarpa - Betula glandulosa Wet Shrubland Alliance
CEGL001136 Salix glauca Wet Shrubland
A3831 Kalmia microphylla - Cassiope mertensiana - Dryas drummondii Wet Dwarf-shrubland Alliance
CEGL001396 Cassiope mertensiana - Carex paysonis Wet Dwarf-shrubland
A3969 Vaccinium membranaceum - Vaccinium myrtillus - Vaccinium scoparium Montane-Subalpine Shrubland Alliance
CEGL005879 Vaccinium (myrtillus, scoparium) - Luzula glabrata var. hitchcockii Dwarf-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
The fire disturbance interval is typically very long (500 years or greater) within this system. Historically, stand-replacing fires occur infrequently in adjacent associated subalpine woodlands (Arno, 1979). Lightning strikes can cause fire within these systems, although severity and spread is usually variable. Other disturbances include high elevation mining, heavy recreational use, and grazing.
This system is especially fragile due to the extreme limited growing season and soil development. Species that occur in these systems are generally slow growing and decrease in cover and vigor in areas of trampling or grazing.
Removal of disturbance is necessary before any kind of restoration can be considered. Natural recovery may occur over time.
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.
- 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
- Native Species Occasionally Associated with this Ecological System
Original Concept Authors
Montana Version Authors
- Classification and Map Identifiers
Cowardin Wetland Classification:
National Land Cover Dataset:
|Element Global ID
||CES306.810, Rocky Mountain Alpine Dwarf-Shrubland
5207: Rocky Mountain Alpine Dwarf-Shrubland
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Arno, S. F. 1980. Forest fire history in the northern Rockies. Journal of Forestry 78(8):460-465.
- Bamberg, S. A., and J. Major. 1968. Ecology of the vegetation and soils associated with calcareous parent materials in three alpine regions of Montana. Ecological Monographs 38(2):127-167.
- Cooper, Stephen V., Peter Lesica, and Deborah S. Page-Dumroese. 1995. Plant community classification for alpine vegetation on the Beaverhead National Forest, Montana. Ogden, UT (324 25th Street, Ogden 84401): U.S. Dept. of Agriculture, Forest Service, Intermountain Research Station.