Rocky Mountain Cliff, Scree and Rock Outcrops
Global Name:
Rocky Mountain Cliff, Scree & Rock Vegetation
Global Rank:
G4G5
State Rank:
S5
(see reason below)
External Links
State Rank Reason
This non-vegetated or sparsely-vegetated habitat is common and widespread and it is not threatened nor intrinsically vulnerable.
General Description
This National Vegetation Classification Group is composed of barren, rocky and sparsely vegetated landscapes from the foothills to the subalpine zone throughout the mountains of western and central MT, including the island mountain ranges. It includes steep cliff faces, rock outcrops, scree and talus slopes and areas of exposed bedrock on igneous, sedimentary, and metamorphic bedrock types. It is characteristically dry and sparsely vegetated, typically having less than 10% plant cover. There may be small patches of dense vegetation, or scattered plants within these communities. Because the elevation range is so broad, species composition may vary widely. Near timberline, this type may transition seamlessly into G571 Alpine Bedrock & Scree, especially along large scree and talus slopes that extend along a large elevational gradient.
This group is equivalent to the Rocky Mountain Cliff, Canyon and Massive Bedrock Ecological System.
Diagnostic Characteristics
Cliffs, Scree, Talus, Rock Outcrops, Canyons, Bedrock, Sparsely-Vegetated; Shallow and/or Poorly Developed Soils; Less than 10% Vascular Plant Cover; Rocky Mountain Region.
This Group can be differentiated from similar types largely by geography and landscape position. Areas at or above timberline are included in G571 - Alpine Bedrock and Scree, while G567 - Great Plains Cliff and Rock Outcrops can be distinguished by geographic location and setting. It can be differentiated from other nearby types by the high percentage of rock cover and the low percentage of vegetative cover (gen <10%).
Similar Systems
Range
This group is located throughout the Rocky Mountains, including the mountainous areas of western Montana and the isolated island ranges of central Montana.
In Montana, G565 occurs throughout Level III Ecoregions 15 (Northern Rockies), 16 (Idaho Batholith), 17 (Middle Rockies) and 41 (Canadian Rockies)
In Montana, G565 occurs within these Major Land Resource Areas: 43A-Northern Rocky Mountains and 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
Beaverhead, Big Horn, Blaine, Broadwater, Carbon, Cascade, Chouteau, Deer Lodge, Fergus, Flathead, Gallatin, Glacier, Golden Valley, Granite, Hill, Jefferson, Judith Basin, Lake, Lewis and Clark, Lincoln, Madison, Meagher, Mineral, Missoula, Park, Phillips, Pondera, Powell, Ravalli, Sanders, Silver Bow, Stillwater, Sweet Grass, Teton, Wheatland
Based on 2025 land cover layer.
Spatial Pattern
Large Patch
Environment
The Rocky Mountain Cliff, Scree & Rock Outcrop Group occurs on steep cliff faces, in narrow canyons, on smaller rock outcrops, on scree and talus slopes and in areas of exposed bedrock. These habitats are shaped by the parent material, climate, aspect, and physical weathering patterns making them distinct from neighboring vegetated communities (Larson et al 2000). Soils are patchy, thin and/or poorly developed, and moisture for plant growth is primarily retained in crevices in the rock substrate. Limited soil availability, harsh microclimates, and water stress impose physiological constraints on plant establishment and growth and plant community development. Within this type, a mosaic of microhabitats may be present within cliff habitats, small ledges, overhangs, and cracks and crevices (Graham and Knight 2004). These microhabitats may provide critical habitat for endemic or rare plant species.
Vegetation
This group is characteristically dry and sparsely-vegetated, typically having less than 10% plant cover. Species composition includes individuals present in adjacent habitats (unless exposed parent material is radically different) and shrubby or herbaceous species adapted to these stable or shifting, rocky habitats. Soil development is limited and often patchy, as is the herbaceous cover. There may be small patches of dense vegetation, or scattered plants within these communities, especially within cracks and crevices. Particular species present at a site are determined largely by rock type and its physical and chemical properties, formation and position on the landscape, elevation, aspect, and overall geographic location. As such, the potential list of species present within this group is quite large and may include various trees, shrubs, forbs and graminoids.
Shrubs adapted to xeric growing conditions and rocky soils are often present, including Oceanspray (Holodiscus discolor), Currants and Gooseberries (Ribes species), Ninebark (Physocarpus malvaceus), Rose (Rosa species), Common Juniper (Juniperus communis), Lewis’ Mock Orange (Philadelphus lewisii), Oregon-grape (Berberis repens), Skunkbush Sumac (Rhus trilobata), American Red Raspberry (Rubus idaeus) or Serviceberry (Amelanchier alnifolia).
Herbaceous plants inhabit both the talus and scree slides and fractures in the cliff faces. Potential forbs are many, but commonly include Penstemon (Penstemon species), Buckwheat (Eriogonum species), Silver Sagewort (Artemisia ludoviciana), Michaux’s Sagewort (Artemisia michauxiana), and Spotted Saxifrage (Saxifraga bronchialis). Potential graminoids vary significantly among sites. Xeric-adapted ferns such as Cliff Fern (Woodsia species), Brittle Bladder Fern (Cystopteris fragilis) and Rockbrake (Cryptogramma acrostichoides) often occur in fractures of the bedrock, cliff faces or on toeslopes of talus slides. Lichen cover can be high on larger size talus and rock faces.
In Montana, this barren and sparsely-vegetated group is currently represented by 2 Alliances and 3 Associations within the National Vegetation Classification. Additional plant communities certainly occur within this Group in MT, either undocumented, undescribed, or not attributed to MT as of yet.
National Vegetation Classification
Download the complete NVC hierarchy for Montana
TT4 B04 Temperate-Boreal Grassland and Shrubland
TT4.d S60 Temperate-Boreal Open Rock
TT4.d1 F120 Temperate-Boreal Cliff and Rock Outcrop
TT4.d1.Nb D052 Western North American Temperate Cliff, Scree and Rock
TT4.d1.Nb.1 M887 Western North American Cliff, Scree and Rock
TT4.d1.Nb.1.b G565 Rocky Mountain Cliff, Scree and Rock
A3741 Aquilegia flavescens - Phacelia hastata Cliff, Scree and Rock Alliance
CEGL005899 Aquilegia flavescens - Senecio megacephalus Sparse Vegetation
CEGL005901 Phacelia hastata - (Penstemon ellipticus) Sparse Vegetation
A4146 Sullivantia hapemanii - Mimulus spp. Wet Rock Alliance
CEGL005509 Sullivantia hapemanii - Mimulus spp. Wet Rock Vegetation
*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 rock-dominated and sparsely-vegetated communities are influenced by the type of parent rock, elevation, aspect, climate, and both physical and chemical weathering patterns. Erosional and depositional processes are locally important. All of these processes and characteristics can have a strong influence over which species occur within these habitats (Larson et al 2000).
Management
This group is generally not a focus for management or restoration activities. Avoiding or preventing impacts to areas within this type, particularly those that support rare taxa or Species of Concern is the primary means of management.
Restoration Considerations
See Management Section.
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
Original Concept Authors
G. Kittel and M.S. Reid 2010
Montana Version Authors
S. Mincemoyer, E. Luther, L. Vance and T. Luna
Version Date
12/5/2024
References
- Literature Cited AboveLegend:
View Online Publication
Graham, L. and R.L. Knight. 2004. Multi-Scale Comparisons of Cliff Vegetation in Colorado. Plant Ecology 170(2): 223-234- Larson, D. W., U. Matthes, J. A. Gerrath, N. W. K. Larson, J. M. Gerrath, J. C. Nekola, G. L. Walker, S. Porembski, and A. Charlton. 2000. "Evidence for the Widespread Occurrence of Ancient Forests on Cliffs". Journal of Biogeography. 27 (2): 319-331.
- Web Search Engines for Articles on "Rocky Mountain Cliff, Scree & Rock Vegetation"
