Name:
Empetrum nigrum - Vaccinium uliginosum - Vaccinium oxycoccos / Rubus chamaemorus Dwarf-shrubland
Reference:
Eastern Ecology Working Group of...
Description:
These heath-sedge bogs occur in alpine and subalpine depressions in the montane regions of the northeastern United States. Found at elevations above 3500 feet, these peatlands form where bedrock basins retain water (or ice) through all or most of the year. The bog vegetation covers the flat portion of the basin, and may also creep upslope on the margins. The bogs may receive small amounts of runoff from upslope bedrock, but conditions are extremely nutrient-poor. Combined with the cold temperatures and frequent clouds and fog, this creates conditions suitable for only a limited number of subalpine and boreal species. The substrate is acidic, permanently saturated organic soil, where lenses of peat beneath the surface may remain frozen through much of the growing season. Trees are generally absent, although a few small islands of stunted Picea mariana and Abies balsamea may occur. Dwarf-shrubs are the dominant vascular layer, with coverage of up to about 50%. Among the dwarf-shrubs, herbs (primarily sedges) are scattered, with up to 20% cover. Bryoids are generally more extensive than the vascular vegetation, approaching 100% cover. The dwarf-shrub cover is generally a mixture of Vaccinium uliginosum, Empetrum nigrum, Chamaedaphne calyculata, Ledum groenlandicum, Kalmia polifolia, Kalmia angustifolia, and Vaccinium oxycoccos. Eriophorum vaginatum ssp. spissum and Trichophorum caespitosum (= Scirpus cespitosus) are typically the most abundant graminoids; Carex magellanica ssp. irrigua (= Carex paupercula), Carex canescens, and Carex pauciflora may be present in lower abundance. Rubus chamaemorus is a diagnostic herb, although it may not always be present. Sphagnum spp. are the most abundant bryophytes, particularly Sphagnum capillifolium, Sphagnum fuscum, Sphagnum fallax, and Sphagnum magellanicum. The combination of subalpine species such as Vaccinium uliginosum and bog species such as Eriophorum vaginatum ssp. spissum is diagnostic. This community is related to, and may be adjacent to, Picea mariana / Kalmia angustifolia Dwarf-shrubland (CEGL006031); that association is less wet and lacks the true bog species such as Eriophorum vaginatum ssp. spissum, Chamaedaphne calyculata, and Sphagnum spp. It is also related to Kalmia angustifolia - Chamaedaphne calyculata / Rubus chamaemorus / Cladina spp. Dwarf-shrubland (CEGL006425), but that type is not constantly saturated and occurs on subalpine or alpine slopes rather than basins.
Accession Code:
VB.CC.19516.EMPETRUMNIGRUMV
Plot-observations of this Community Concept:
0
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