Name:
Carex albonigra - Myosotis asiatica Herbaceous Vegetation
Reference:
Western Ecology Working Group of...
Description:
This fell-field association has been sampled in the alpine of Glacier National Park, Montana, and Waterton Lakes National Park, Alberta. It is predominantly a small- (to large-) patch fell-field community, characteristic and extensive at the highest elevations and most extreme and exposed alpine environments; its recorded elevation range is from 2060 to 2630 m (6755-8625 feet), though most of the sites are above 2400 m (7870 feet). It usually is dispersed across expansive rolling upland and frost rubble-mantled summits; topographic positions include flat mountain summits, ridges, exposed upper slopes and rolling uplands. Because of high elevations and exceedingly exposed positions, this is one of the most wind-impacted environments (prevailing winds being from the southwest); xeric conditions are in effect through most of the year. Being swept free of snow and protective cover facilitates frost action, which results in patterned ground features with the polygonal arrangement of rocks. The ground surface is dominated by exposed rock, mostly in excess of 60% cover, with undeveloped and well-drained soils restricted to pockets and vegetation-covered patches. The modal aspect is a very low-growing turf, scattered in small patches across an undulating landscape. The vascular plant cover is highly variable, from 1% to approaching 60%, with most of the sampled occurrences having less than 30% cover; there is not one species or species group that can be considered strictly characteristic. <i>Dasiphora fruticosa ssp. floribunda</i> is the only dwarf-shrub of note with cover usually less than 5%; for its cover to exceed 10% would be indicative of a different community. The most diagnostic graminoids are <i>Carex albonigra</i> and <i>Carex rupestris</i> with <i>Carex nardina</i> occurring sporadically; their single or combined cover seldom exceeds 5%. <i>Festuca brachyphylla, Trisetum spicatum, Luzula spicata, Poa alpina</i>, and <i>Poa glauca</i> also exhibit high constancy and low cover, and <i>Calamagrostis purpurascens</i> is present in the lower elevation examples of the type. The distinctive cushion plant <i>Silene acaulis</i> attains its greatest constancy and cover in this type, often constituting the dominant forb. Four forbs, <i>Myosotis asiatica (= Myosotis alpestris), Potentilla nivea, Rhodiola rosea (= Sedum roseum)</i>, and <i>Minuartia rossii (= Arenaria rossii)</i>, are more consistently present in this than other types. Other high-constancy forbs include <i>Minuartia obtusiloba (= Arenaria obtusiloba), Smelowskia calycina, Sedum lanceolatum, Erigeron compositus, Oxytropis campestris</i>, and <i>Selaginella densa var. standleyi (= Selaginella standleyi)</i>.
Accession Code:
VB.CC.32190.CEGL005863
Plot-observations of this Community Concept:
0
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