Common (Translated Scientific) Name: Black Alpine Sedge - Creeping Sibbaldia Wet Meadow

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This association is well documented from throughout Glacier National Park, Montana, and it occurs as well in the alpine of Waterton Lakes National Park, Alberta. It occurs only in the highest subalpine to alpine zone where it occupies sites that retain their snowload extremely late into the growing season. Often these sites are swales or lee slope positions that receive much greater snowloads than other landscape positions. The patches occur in gently rolling terrain with slopes seldom exceeding 20% and all aspects being represented; elevations represented range from 2000 to 2400 m (6100-7870 feet). The fact that meltoff occurs so late in the season produces a very reduced growing season, though the abundant meltwater creates soils that are almost always continuously saturated. The amount of exposed rock and soil generally does not exceed 10% with the great majority of the ground surface covered by litter or basal vegetation. Carex nigricans, an indicator of snowbed conditions, has at least 10% cover, but can have well over 80% cover, and forms a low-growing (<0.08 m high) turf. Other snowbed-associated graminoids consistently present include Juncus drummondii, Juncus mertensianus, Carex spectabilis, Luzula glabrata, and Phleum alpinum. Where moist to wet conditions follow snowpack meltoff, forbs may attain appreciable cover, including Erigeron peregrinus, Hypericum scouleri, Trollius laxus, Parnassia fimbriata, Senecio triangularis, and Triantha glutinosa. The forbs most consistently present and indicative of more modal conditions include Sibbaldia procumbens, Epilobium anagallidifolium, Packera streptanthifolia, Symphyotrichum foliaceum, and Ranunculus eschscholtzii; the combined cover within the forb layer is usually in the range of 5 to 20%. The dwarf-shrub component, if present, has less than 5% cover, with Salix arctica and Phyllodoce glanduliflora being those most consistently present.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association, as identified for Glacier and Waterton Lakes national parks, is floristically somewhat distinct from the Carex nigricans communities sampled by Cooper et al. (1997) from the Beaverhead National Forest. The presence of Carex spectabilis, Luzula glabrata, Trollius laxus, Parnassia fimbriata, Senecio triangularis, and Triantha glutinosa in the Glacier plots suggest a different plant association than that found by Cooper et al. (1997); hence it has been accorded its own name as a distinct plant association. There are affinities between the two, a reflection of their occurrence in very similar ecological niches, and also affinities with the Carex nigricans communities found in the northern Cascades and coastal mountains of British Columbia. However, the Carex nigricans association identified by Cooper et al. (1997) is more similar floristically to ~Carex nigricans - Juncus drummondii Wet Meadow (CEGL001818)$$ from the central Rocky Mountains in Colorado (Carsey et al. 2003b) and may represent the northerly extent of that type.

Similar NVC Types: No Data Available

note: No Data Available