Circumpolar Arctic Vegetation Unit G4

 

Hierarchy of Geobotanical Vegetation Map Units (Walker DA 2002)

Imnaviat Creek, Alaska. Photo D.A. Walker.
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map legend color for unit G4G4. Tussock-sedge, dwarf-shrub, moss tundra

Moist tundra, dominated by tussock cottongrass (Eriophorum vaginatum) and dwarf shrubs <40 cm tall. Mosses are abundant. Subzone E, some Subzone D.

Detailed Description

Moist tussock tundra, mainly in Subzones D and E, on cold acidic soils. This is the zonal vegetation in Subzone E on unglaciated landscapes with ice-rich permafrost and shallow active layers, e.g., northern Alaska and Chukotka. Plant cover is nearly continuous (80-100%). The height of the plant canopy varies from about 20-40 cm. A less robust form of tussock tundra grows in Subzone D, with smaller tussock sedges and less abundant and shorter shrubs that do not overtop the tussocks.
Area: 336 x 1000 km2.

Representative Syntaxa

Sphagno-Eriophoretum vaginati Walk. et al. 1994 (Alaska); Carici arctisibiricae-Hylocomietum alaskani vicariant of Pinguicula villosa Matv. 1994 (Taimyr Peninsula) (cf. Ledo decumbentis-Betuletalia glandulosae Rivas-Martinez et al. 1999).

Dominant Plants

Tussock sedges with other sedges, and prostrate and erect dwarf-shrubs, and mosses. Other common plants include grasses, forbs, and lichens.

    1. Tussock sedges: Eriophorum vaginatum; Carex lugens;
    2. Sedge: Carex bigelowii/arctisibirica/consimilis; Eriophorum triste;
    3. Prostrate and erect dwarf-shrubs: Ledum palustre spp. decumbens; Betula nana s.l.; Salix pulchra; Vaccinium vitis-idaea; Vaccinium uliginosum ssp. microphyllum; Arctous alpina; Rubus chamaemorus; Rubus arcticus; Cornus suecica;
    4. Moss: Sphagnum; Hylocomium splendens; Oncophorus wahlenbergii; Aulacomnium turgidum; Dicranum; Polytrichum;
    5. Grass: Arctagrostis latifolia;
    6. Forb: Pedicularis lapponica; Pedicularis labradorica; Bistorta plumosa; Polygonum tripterocarpum; Saxifraga nelsoniana; Nardosmia frigida;
    7. Lichen: Flavocetraria; Cladina rangiferina; Cladonia amaurocraea; Ochrolechia frigida; Alectoria nigricans; Bryocaulon divergens;

a=acidic, n=non-acidic