Name:
Kobresia myosuroides - Euphrasia disjuncta Herbaceous Vegetation
Reference:
Western Ecology Working Group of...
Description:
This is a relatively rare, small-patch, turf type found at the upper range of alpine environments in northwestern Montana, above 2200 m (7200 feet). The few examples were found on southerly exposures with low- to moderate-gradient slopes. It forms relatively thick mats of dense bog sedge vegetation that carpet terraced slopes, fell-fields, and colluvial slopes. Despite having a relatively early snow meltoff, this type receives an ample moisture supply, being subirrigated by waters percolating from surrounding snowfields. Soils are sufficiently moist to wet to promote slow soil creep or solifluction. Parent materials include argillites and limestone. The usually dense turf encourages the development of a humus-rich upper profile that has a dense root mat, which in turn promotes a coherent vegetation layer that persists under unstable slope conditions (solifluction). This uncommon type is one of the floristically richest alpine plant communities. The usually dense turf is composed of a variety of Carex and Kobresia species, but by far the dominant species is bunch-forming Kobresia myosuroides, the interlaced roots of which create a stable turf surface. Dwarf-shrubs, including Dasiphora fruticosa ssp. floribunda, Dryas octopetala, and Salix arctica, are consistently present in trace amounts. The presence of the diminutive annual Euphrasia disjuncta (= Euphrasia arctica), though not unique to this community, does set it apart from a host of other alpine communities. Other high-constancy forbs include Gentiana prostrata, Polygonum viviparum, Polygonum bistortoides, Potentilla diversifolia, Rhodiola rosea (= Sedum roseum), Dodecatheon pulchellum, Solidago multiradiata, Hedysarum sulphurescens, and Zigadenus elegans; only the last three named forbs were consistently represented with more than 5% cover. Graminoids consistently part of the mixed turf include Festuca idahoensis, Festuca brachyphylla, Trisetum spicatum, Poa alpina, Poa nemoralis ssp. interior (= Poa interior), Luzula spicata, and Carex albonigra; none of these with high cover. The bryophyte Aulacomnium palustre contributes appreciably to the impression of continuous vegetative cover.
Accession Code:
VB.CC.24982.KOBRESIAMYOSURO
Plot-observations of this Community Concept:
0
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