The Alaska Vegetation Classification - Alaska Geobotany Center ...

Figure 57-Ericaceous dwarf shrub tundra of Cassiopetetragona wilh some Dtyas ocroperala and Vacciniumvitis-idaea. a snowbed community in he Alaska Range.Distribution and site characteristicoCassiope dwarf shrub tundra is widespreadon moist alpine sites throughout Alaska with the possible exception of the AleutianIslands. It occurs on moist, thin, stony soils, commonly on north slopes, gelifluctionlobes, or snow accumulation areas, although it can occur on ridge crests and slopesof all aspects. Sometimes the soil is a thin organic mat over boulders. Cassiopetundra occurs on sites well protected by snow in winter that become snow free inthe early to middle part of the growing season.Successional status-Successional relations are unknown. These communitiesseem extremely stable.Closely related types-Cassiope mefiensiana communities may be similar tomountain-heath and crowberry communities but have a greater cover of Cassiopespp. They also may be similar to some ericaceous shrub bog communities but lacksphagnum and peat-forming sedges, occur on better drained soils at higher elevations,and are dominated by Cassiope spp.Cassiope tetragona communities may be similar to bearberry, vaccinium, andcrowberry communities but have a greater cover of Cassiope tefragona. Somestands might intergrade with mesic shrub birch-ericaceous shrub stands, butcassiope tundra lacks shrub birch, generally has lower species diversity, and isdominated by Cassiope tetragona.Photographs-Figure 57, this publication.Primary references-Hanson 1953, Jorgenson 1984, Ward 1957, Webber andothers 1978.Communities-Cassiops tetragona (Anderson 1974; Komarkova and Webber 1978,1980; Pegau 1968; Scott 1974a; Webber and others 1978). Cassiope tetragona-Salixrotundifoliamosses (Batten 1977, Jorgenson 1984, Webber and Walker 1975).Cassiope tefragona-Vaccinium uliginosum-mosses (Hanson 1953, Scoff 1974a).Cassiope fetfagona-Vaccinium vitis-idaea (Childs 1969, Webber and others 1978).Cassiope tetragona-Dryas integrifolia (Komarkova and Webber 1978, 1980; Koranda1960). Cassiope tetragona-Vaccinium vitis-idaea-Carex bigelowii-Hylocomiumsplendens-lichens (Jorgenson 1984). Cassiope fefragona-Dicranum spp. (Jorgenson156