Circumpolar Arctic Vegetation Unit G1

 

Hierarchy of Geobotanical Vegetation Map Units (Walker DA 2002)

Amund Ringnes Island, Canada. Photo D.A. Walker.
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map legend color for unit G1G1. Rush/grass, forb, cryptogam tundra

Moist tundra with moderate to complete cover of very low-growing plants. Mostly grasses, rushes, forbs, mosses, lichens, and liverworts. Subzone A and Subzone B.

Detailed Description

Moist tundra on fine-grained, often hummocky soils in subzones A and B. Plant cover is moderate (40-80%), and the vegetation forms a single layer generally 5-10 cm tall. This is the zonal vegetation in Subzone A, often occurring in somewhat more protected areas with moderate snow cover. Except for the greater density of plants, particularly rushes and grasses, it is similar in composition to cryptogam, cushion-forb barrens (Unit B1).
Area: 141 x 1000 km2.

Representative Syntaxa

Communities of the class Thlaspietea rotundifolii Br.-Bl. et al. 1947 (Saxifrago stellaris-Oxyrion digynae Gjaerev. 1950, e.g., Luzuletum arcuatae Nordh. 1928), and Salicetea herbaceae (Luzulion nivalis (Nordh. 1936) Gjaerev. 1956, e.g., Alopecuro alpini-Tomenthypnetum (Hadac 1946) Dierss. 1992 and Cerastio regelii-Poetum alpinae Dierss. 1992).

Dominant Plants

Grasses and rushes are usually the dominant vascular plants. Forbs are abundant. Mosses, lichens, and liverworts are common. Cryptogamic crusts composed of cyanobacteria and black crustose lichens are common. In Subzone B, prostrate dwarf shrubs and sedges are present but not dominant.

    1. Grass: Alopecurus alpinus; Dupontia fisheri; Deschampsia borealis/brevifolia; Poa abbreviata; Poa arctica;
    2. Rush: Luzula nivalisa; Luzula confusaa;
    3. Forb: Cardamine bellidifoliaa; Cerastium regeliin; Minuartia rossiin; Papaver dahlianum ssp. polare; Potentilla hyparcticaa; Saxifraga oppositifolian; Ranunculus hyperboreus; Draban; Stellarian; Oxyria digyna;
    4. Moss: Aulacomnium turgidum; Tomentypnum nitensn; Ditrichumn; Oncophorus wahlenbergii; Polytrichum; Racomitriuma; Schistidium;
    5. Lichen: Lecanora; Biatora; Pertusaria; Ochrolechia; Thamnolia; Cetrariella; Flavocetraria; Stereocaulonn;
    6. Liverwort: Liverworts;
    7. Cyanobacteria: Cyanobacteria;
    8. Black crustose lichens: Black crustose lichen;
    9. Prostrate dwarf shrubs: Dryasn; Salix polaris; Salix arctican;
    10. Sedge: Carex aquatilis; Eriophorum;

a=acidic, n=non-acidic