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G316 Dryas octopetala - Phyllodoce spp. - Salix arctica Alpine Dwarf-shrubland & Krummholz Group
Type Concept Sentence: This widespread group occurs above upper timberline throughout the Rocky Mountains cordillera and includes alpine areas of mountain ranges in Utah and Nevada, the Sierra Nevada in California, eastern Cascade Range in eastern Oregon and Washington, and north into Canada, but is more prominent in the northern extent. It is composed of low-statured shrubs such as Cassiope mertensiana, Dryas integrifolia, Dryas octopetala, Phyllodoce empetriformis, Salix arctica, Salix reticulata, or Salix vestita with or without an herbaceous component.
Common (Translated Scientific) Name: Eight-petal Mountain-avens - Mountain-heath species - Arctic Willow Alpine Dwarf-shrubland & Krummholz Group
Colloquial Name: Rocky Mountain-Sierran Alpine Dwarf-shrubland & Krummholz
Hierarchy Level: Group
Type Concept: This widespread group occurs above upper timberline throughout the Rocky Mountains cordillera and includes alpine areas of ranges in Utah and Nevada, Sierra Nevada in California, eastern Cascade Range, eastern Oregon and Washington, and north into Canada, but is more prominent in the northern extent. The vegetation is 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 in height. Dense tuffs of graminoids and scattered forbs are usually present. Dryas integrifolia- and Dryas octopetala-dominated communities occur on more windswept and drier sites than the heath communities. Within the heath communities Cassiope mertensiana, Phyllodoce empetriformis, Salix arctica, Salix reticulata, or Salix vestita can be dominant shrubs. Other common shrub associates include Arctostaphylos uva-ursi, Dasiphora fruticosa ssp. floribunda, Ericameria discoidea, Kalmia microphylla, Ledum glandulosum, Phyllodoce glanduliflora, Ribes montigenum, and Vaccinium spp. The herbaceous layer is a mixture of forbs and graminoids, especially sedges, including Antennaria lanata, Caltha leptosepala, Carex spectabilis, Carex nigricans, Castilleja spp., Deschampsia cespitosa, Erigeron spp., Erythronium spp., Juncus parryi, Luetkea pectinata, Luzula piperi, Oreostemma alpigenum, Pedicularis spp., Polemonium viscosum, and Polygonum bistortoides. This group occurs in areas of level or concave glacial topography, with late-lying snow and subirrigation from surrounding slopes. Elevations are above 3360 m in the Colorado Rockies but drop to less than 2100 m in northwestern Montana and in the mountains of Alberta. Soils have become relatively stabilized in these sites, are moist but well-drained, strongly acidic, and often with substantial peat layers. Vegetation in these areas is controlled by snow retention, wind desiccation, permafrost, and a short growing season.
Diagnostic Characteristics: This alpine group is 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 in height. Characteristic species include drier site Dryas integrifolia and Dryas octopetala to the more typical mesic heath communities dominated by Cassiope mertensiana, Phyllodoce empetriformis, Ribes montigenum, Salix arctica, Salix reticulata, or Salix vestita with Arctostaphylos uva-ursi, Kalmia microphylla, Ledum glandulosum, Phyllodoce glanduliflora, and Vaccinium spp. present to codominant. Wider-ranging shrubs will be codominated by diagnostic alpine herbaceous species.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This group is more distinct in the mesic northern extent than in the southern and drier ranges in the Great Basin and Colorado Plateau. In the northern extent, the dwarf-shrub layers tend to be denser and characterized by distinctive alpine heath species Cassiope mertensiana, Phyllodoce empetriformis, Salix glauca, and Salix reticulata. In the southern extent, stands dominated by Salix arctica, Salix reticulata, or Salix nivalis are less distinctive and occur as patches within the alpine turf or mesic bands around snowbeds (Cooper et al. 1997).
The diagnostic species in this physiognomically defined alpine group occur on a variety of sites. Dryas octopetala and Dryas integrifolia often occur on harsh wind-blown sites on dry turf, cushion plant fell-fields or unstable scree slopes, whereas the heath types of Cassiope mertensiana, Salix reticulata, or Phyllodoce empetriformis occur as snowbed or wetland communities (Cooper et al. 1997). Some of the dwarf Salix species, such as Salix arctica, form mesic patches within the larger alpine turf communities (Lewis 1970, Zwinger and Willard 1996, Cooper et al. 1997).
The diagnostic species in this physiognomically defined alpine group occur on a variety of sites. Dryas octopetala and Dryas integrifolia often occur on harsh wind-blown sites on dry turf, cushion plant fell-fields or unstable scree slopes, whereas the heath types of Cassiope mertensiana, Salix reticulata, or Phyllodoce empetriformis occur as snowbed or wetland communities (Cooper et al. 1997). Some of the dwarf Salix species, such as Salix arctica, form mesic patches within the larger alpine turf communities (Lewis 1970, Zwinger and Willard 1996, Cooper et al. 1997).
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: This group is 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 in height. Dense tuffs of graminoids and scattered forbs may occur forming an herbaceous layer.
Floristics: The vegetation is 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 in height. Dense tuffs of graminoids and scattered forbs are usually present. Dryas integrifolia- and Dryas octopetala-dominated communities occur on more windswept and drier sites than the heath communities. Within the heath communities Cassiope mertensiana, Phyllodoce empetriformis, Salix arctica, Salix reticulata, or Salix vestita can be dominant shrubs. Other common shrub associates include Arctostaphylos uva-ursi, Dasiphora fruticosa ssp. floribunda, Ericameria discoidea, Kalmia microphylla, Ledum glandulosum, Phyllodoce glanduliflora, Ribes montigenum, and Vaccinium spp. The herbaceous layer is a mixture of forbs and graminoids, especially sedges, including Antennaria lanata, Calamagrostis breweri, Caltha leptosepala, Carex spectabilis, Carex nigricans, Carex rupestris, Castilleja spp., Deschampsia cespitosa, Erigeron spp., Erythronium spp., Geum rossii, Juncus parryi, Luetkea pectinata, Luzula piperi, Oreostemma alpigenum (= Aster alpigenus), Pedicularis spp., Polemonium viscosum, Polygonum bistortoides, Polygonum viviparum, and Sibbaldia procumbens. Floristic information was compiled from Bamberg (1961), Willard (1963), Bamberg and Major (1968), Lewis (1970), Komarkova (1976, 1980), Zwinger and Willard (1996), Cooper et al. (1997), and Billings (2000).
Dynamics: No Data Available
Environmental Description: This widespread group occurs above upper timberline throughout the Rocky Mountain cordillera, including alpine areas of ranges in Utah and Nevada, and north into Canada, but is more prominent in the northern extent. Elevations are above 3360 m in the Colorado Rockies but drop to less than 2100 m in northwestern Montana and in the mountains of Alberta. This group occurs in areas of level or concave glacial topography, with late-lying snow and subirrigation from surrounding slopes. Soils have become relatively stabilized in these sites, are moist but well-drained, strongly acidic, and often have substantial peat layers.
Geographic Range: This group occurs above upper timberline throughout the Rocky Mountain cordillera, including alpine areas of ranges in Utah and Nevada, eastern Cascade Range, eastern Oregon and Washington, and north into Canada.
Nations: CA,US
States/Provinces: AB, BC, CO, ID, MT, NM, NV, OR, UT, WA, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.857571
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: < Alpine Rangeland (410) (Shiflet 1994)
- Bamberg, S. A. 1961. Plant ecology of alpine tundra area in Montana and adjacent Wyoming. Unpublished dissertation, University of Colorado, Boulder. 163 pp.
- 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.
- Billings, W. D. 2000. Alpine vegetation of North America. Pages 537-572 in: M. G. Barbour and W. D. Billings, editors. North American terrestrial vegetation. Second edition. Cambridge University Press, New York. 434 pp.
- Cooper, S. V., P. Lesica, and D. Page-Dumroese. 1997. Plant community classification for alpine vegetation on Beaverhead National Forest, Montana. Report INT-GTR-362. USDA Forest Service, Intermountain Research Station, Ogden, UT. 61 pp.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2019a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Komarkova, V. 1976. Alpine vegetation of the Indian Peaks Area, Front Range, Colorado Rocky Mountains. Unpublished dissertation, University of Colorado, Boulder. 655 pp.
- Komarkova, V. 1980. Classification and ordination in the Indian Peaks area, Colorado Rocky Mountains. Vegetatio 42:149-163.
- Lewis, M. E. 1970. Alpine rangelands of the Uinta Mountains, Ashley and Wasatch national forests, Region 4 of the USDA Forest Service. Unpublished report mimeographed for USDA Forest Service, Region IV, Ogden, UT. 75 pp.
- Shiflet, T. N., editor. 1994. Rangeland cover types of the United States. Society for Range Management. Denver, CO. 152 pp.
- Willard, B. E. 1963. Phytosociology of the alpine tundra of Trail Ridge, Rocky Mountain National Park, Colorado. Unpublished dissertation, University of Colorado, Boulder.
- Zwinger, A. H., and B. E. Willard. 1996. Land above the trees: A guide to American alpine tundra. Johnson Books, Boulder, CO. 425 pp.