Name:
Arctostaphylos uva-ursi / Festuca campestris - Festuca idahoensis Dwarf-shrubland
Reference:
Western Ecology Working Group of...
Description:
This dwarf-shrubland type is found in the montane to mid-alpine zones of the northern Rockies in northwestern Montana, and extending north into the montane zone of Alberta. The elevation where it occurs ranges almost 790 m (2600 feet), from 1340 to 2130 m (4400-7000 feet), essentially ranging from the montane to the mid-alpine. It occurs on moderate to steep slopes with predominantly southerly exposures, though it has been found on all aspects. This dwarf-shrubland is associated with positions that can be inferred to be wind-battered. It has been recorded exclusively from sedimentary substrates, predominantly limestones and siltstones. These have weathered into thin, fine-textured, and well- to excessively drained soils whose water regime is characterized as predominantly subxeric. The inference that these are stressful sites is borne out in the species composition and structure with the dwarf-shrub Arctostaphylos uva-ursi functioning as the community dominant and other low-shrubs, Juniperus horizontalis, Dasiphora fruticosa ssp. floribunda, Rosa woodsii, and Juniperus communis, being common associates. Arctostaphylos uva-ursi cover ranges from about 5% to as high as 70%, averaging about 30%. Arctostaphylos cover appears to be loosely inversely correlated with cover of the dominant (and diagnostic) grasses, Festuca campestris and Festuca idahoensis, whose average canopy cover hovers around 20-25% and 2-5%, respectively. The only other graminoids with even moderate constancy are Koeleria macrantha and Agoseris glauca, with cover seldom exceeding 5%. High cover values (>30%) for Danthonia parryi characterize higher elevation and relatively mesic stands. Other graminoids present and associated with severe high-elevation sites include Calamagrostis purpurascens and Carex elynoides. The forb component is highly diverse, though individual stands are not as diverse. Forbs present in at least half the stands include Oxytropis sericea, Penstemon confertus, Packera cana (= Senecio canus), Sedum lanceolatum, Zigadenus elegans, Hedysarum sulphurescens, Galium boreale, Lupinus sericeus, Erigeron caespitosus, Gaillardia aristata, Allium cernuum, Achillea millefolium, and Fragaria virginiana. Cover for any of these is typically low, except the cover of Lupinus sericeus and Hedysarum sulphurescens which tends to exceed 5%.
Accession Code:
VB.CC.28160.ARCTOSTAPHYLOSU
Plot-observations of this Community Concept:
0
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