Alpine heath snowbank
Alpine heath snowbank (S1S2)
Alpine heath snowbanks are found in well-drained, relatively protected lee positions on alpine summits where winter snow accumulates to significant depths (greater than it does in sedge - rush - heath meadows). It also occurs just above krummholz, elevationally. The elevation range for this community is approximately 4,600–5,500 ft. Dwarf shrubs and lowland plants are present in relative abundance (greater than in sedge - rush - heath meadows), and total vegetative cover is high. This community is equivalent to Bliss’ (1963) dwarf shrub heath community.
Compositionally, this community differs from the sedge - rush - heath meadow by the presence of Labrador tea (Ledum groenlandicum), black crowberry (Empetrum nigrum), dwarf bilberry (Vaccinium cespitosum), and various lowland plants restricted to snowbank areas. In contrast to the wetter alpine herbaceous snowbank/rill community, it lacks wet-site species such as peat mosses, Veratrum viride (false hellebore), and Calamagrostis canadensis (bluejoint). It is distinguished from subalpine dwarf shrublands by the presence of alpine species that are absent or in very low cover in that community. The higher cover of species common in the protected snowbank communities (see list above) also differentiates this community from subalpine dwarf shrublands.
Characteristic vegetation: Several of the indicator species for this community are Labrador tea (Ledum groenlandicum), crowberries (Empetrum spp.), and dwarf bilberry (Vaccinium cespitosum). Other species that may be present incude alpine bilberry (Vaccinium uliginosum), mountain cranberry (Vaccinium vitis-idaea), bunchberry (Cornus canadensis), highland rush (Juncus trifidus), mountain sandwort (Minuartia groenlandica), starflower (Trientalis borealis), Canada mayflower (Maianthemum canadense), common hairgrass (Deschampsia flexuosa), and large-leaved goldenrod (Solidago macrophylla).
Several rare species may be found in this community, including moss-plant (Harrimanella hypnoides), alpine bearberry (Arctostaphylos alpina), Bigelow's sedge (Carex bigelowii), diapensia (Diapensia lapponica), mountain heath (Phyllodoce caerulea), and dwarf birch (Betula glandulosa). Wet-site species such as peat mosses, false hellebore, and bluejoint are absent.
Good examples of alpine heath snowbanks occur on Franconia Ridge and in the alpine zone of the Presidential Range.
This community frequently occurs along with other alpine communities as part of a larger alpine tundra system.
Alpine heath snowbank community on Mt. Lafayette (photo by Ben Kimball)
moss-plant (Harrimanella hypnoides) is a rare species found in some
alpine heath snowbank communities (photo by Dan Sperduto)