Circumpolar Arctic Vegetation Unit G3

 

Hierarchy of Geobotanical Vegetation Map Units (Walker DA 2002)

Ambarchik, Yakutia, Russia. Photo D.A. Walker.
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map legend color for unit G3G3. Non-tussock sedge, dwarf-shrub, moss tundra

Moist tundra dominated by sedges and dwarf shrubs <40 cm tall, with well-developed moss layer. Barren patches due to frost boils and periglacial features are common. Subzone D and Subzone C, some Subzone E.

Detailed Description

Moist tundra mainly in Subzone D on peaty nonacidic soils; also found in Subzones C and E. Frost boils (barren patches of cryoturbated soil) are common on silty soils (spotted tundra in the Russian literature). This is the zonal vegetation for much of Subzone D. Plant cover varies from 50-100%. Plant heights are generally 10-20 cm. Hemiprostrate and erect shrubs, such as Salix richardsonii, S. reptans, S. glauca, S. pulchra, S. krylovii and Rhododendron lapponicum, are common but generally do not form a closed canopy, and some may grow up to 40 cm high at the southern Subzone D boundary. Low-shrub (40-200 cm tall) and some tall (>2 m) willow thickets occur along stream margins. Well-developed moss layers (5-20 cm thick) are common.
Area: 569 x 1000 km2.

Representative Syntaxa

Dryado integrifoliae-Caricetum bigelowii Walk. et al. 1994 (Alaska, Subzone D, nonacidic tundra); Carici arctisibiricae-Hylocomietum alaskani Matv. 1994 (Taimyr Peninsula) (Scheuchzerio-Caricetea nigrae) (Nordh. 1936) Tx 1937.

Dominant Plants

Mainly sedges, prostrate and hemiprostrate dwarf shrubs, and mosses and liverworts. Other common plants include grasses, basiphilous forbs, and lichens.

    1. Sedge: Carex lugens; Carex misandra; Carex scirpoidea; Carex membranacea; Eriophorum triste;
    2. Prostrate and hemiprostrate dwarf shrubs: Dryas; Salix arctica; Salix reticulata; Salix polaris; Arctous rubra; Cassiope tetragona;
    3. Mosses and liverworts: Tomentypnum nitens; Hylocomium splendens; Aulacomnium turgidum; Rhytidium rugosum; Ditrichum flexicaule; Distichium capillaceum; Ptilidium ciliare;
    4. Grass: Arctagrostis latifolia; Deschampsia borealis/brevifolia; Poa arctica;
    5. Basiphilous forbs: Bistorta vivipara; Silene; Pyrola grandiflora; Senecio frigidus; Pedicularis lanata; Pedicularis capitata ; Chrysanthemum integrifolium; Tofieldia coccinea; Lagotis; Eutrema edwardsii; Astragalus umbellatus; Sagina nivalis; Saxifraga oppositifolia;
    6. Lichen: Thamnolia; Flavocetraria; Peltigera; Dactylina arctica; Mycobilimbia lobulata; Cladonia pocillum; Psoroma hypnorum;

a=acidic, n=non-acidic