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Arctic Tussock Sedge Tundra Alliance | NatureServe Biotics 2019
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Name: Arctic Tussock Sedge Tundra Alliance
Reference: NatureServe Biotics 2019
Description: This tundra alliance is defined by tussock-forming sedges often in combination with dwarf- and low shrubs occurring in the arctic and subarctic regions of Alaska and Canada. The cottongrass <i>Eriophorum vaginatum</i> is the predominant tussock-former on older landscapes and acidic substrates. Tussock formation may transition to the sedge <i>Carex bigelowii</i> across younger landscapes, disturbance-prone landforms and circumneutral substrates. <i>Carex bigelowii</i> tussock tundra is considered a more productive type relative to mature <i>Eriophorum vaginatum</i> tussock tundra. <i>Eriophorum vaginatum</i> tussock tundra is characterized by high constancy of the dwarf-shrub <i>Vaccinium vitis-idaea</i> and the low shrub <i>Betula nana</i>, with the low shrub <i>Ledum palustre ssp. decumbens</i> and the forb <i>Rubus chamaemorus</i> indicating the type. By comparison, <i>Carex bigelowii</i> tussock tundra is characterized by high constancy of the dwarf-shrubs <i>Salix reticulata</i>, and <i>Cassiope tetragona</i> with the dwarf-shrub <i>Dryas octopetala</i> indicating the type. Where <i>Eriophorum vaginatum</i> and <i>Carex bigelowii</i> both contribute to tussock formation, the low shrub <i>Vaccinium uliginosum</i> and the dwarf-shrub <i>Empetrum nigrum</i>, and the forb <i>Polygonum bistorta</i>, have high constancy, with the shrub <i>Salix pulchra</i> indicating the type. For tussock tundra occurring in wet areas of Alaska's Arctic Coastal Plain, shrub abundance appears to increase on microtopographic highs such as high-centered polygons. On a broader scale, low-shrub cover appears to increase in tussock tundra with increasing slope, with the occurrence of dwarf-shrubs increasing in the subalpine. The presence of continuous, ice-rich permafrost renders sites cold and poorly-drained. Shallow organics in the intertussock hollows are underlain by silty mineral soils. Patch size is small to matrix-forming. 
Accession Code: urn:lsid:vegbank.org:commConcept:39528-{EA1A595C-DF5D-4B78-9987-C2434559C07E}
Plot-observations of this Community Concept: 0
      Party Perspective according to: NatureServe (organization)
Perspective from: 19-Jan-2016 to: ongoing
      Names:   UID: ELEMENT_GLOBAL.2.1042181
  Code: A4343
  Translated: Arctic Tussock Sedge Tundra Alliance
  Common: Arctic Tussock Sedge Tundra
  Scientific: Arctic Tussock Sedge Tundra Alliance