Common (Translated Scientific) Name: Western Moss-heather / Payson''s Sedge Wet Dwarf-shrubland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This uncommon association has been documented from only southwestern Montana within the alpine of the Anaconda-Pintlar and Tobacco Root mountains; it is highly likely that it occurs in the East Pioneer Range as well. Documented sites occur at the base of gentle north- or east-facing slopes at 2870-2960 m (9400-9700 feet). These landscape positions (snowbed sites) accumulate deep snowdrifts, and the release of this load comes late, with soils remaining saturated well into the growing season. Sites often show signs of frost churning and solifluction, suggesting they receive additional upslope moisture. Soils are derived from acidic parent materials and show a moderately acidic reaction (pH 4.8-6.2). Dwarf-shrub canopy cover averages 60% and is dominated by Cassiope mertensiana and Salix arctica (or Salix reticulata) with Phyllodoce glanduliflora occasionally present. Graminoid cover is highly variable, averaging 23%; Carex paysonis is 100% constant and its cover consistently ranges between 7 and 25%. Other graminoids with the potential to codominate include Carex scirpoidea, Carex nigricans and Poa secunda with Poa alpina and Festuca ovina evidencing just high constancy. Average forb cover is 30% with Potentilla diversifolia and Geum rossii usually dominating this component; other high-constancy forbs include Minuartia obtusiloba, Polygonum bistortoides, Erigeron simplex, and Synthyris pinnatifida. This association constitutes one portion of a common mosaic that can include ~Juncus drummondii - Antennaria lanata Alpine Snowbed (CEGL001904)$$, ~Salix arctica - (Salix petrophila, Salix nivalis) / Polygonum bistortoides Dwarf-shrubland (CEGL001431)$$, ~Carex scirpoidea - Geum rossii Alpine Turf (CEGL001866)$$, and ~Carex nigricans Wet Meadow (CEGL001816)$$.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Cassiope mertensiana-dominated associations have been described for the Canadian Rockies (Achuff and Corns 1982), North Cascades of Washington (Douglas and Bliss 1977), and northwestern Montana, holding out the possibility that this is a much more broadly distributed type than implied by Cooper et al. (1997). Some of these vegetation types in which Cassiope mertensiana is an important component have appreciable amounts of other heath species, particularly Phyllodoce empetriformis. Within southwestern Montana, patches of vegetation dominated by Cassiope mertensiana or Phyllodoce empetriformis or variable combinations of these heath species were noted to alternate on the landscape in no set pattern but occupied identical sites to all outward appearances. Combining several of the types having Cassiope mertensiana and/or Phyllodoce empetriformis (and/or Phyllodoce glanduliflora) as significant components into one or more associations should be explored; these types have not received meaningful crosswalking between adjacent regions.

Similar NVC Types: No Data Available

note: No Data Available