Classifiction of Wrangel Island vegetation

S. S. Kholod



The syntaxonomical study of Wrangel Island carried out in accordance to Braun-Blanquet approach is proposed. As a result 29 associations, 1 type of community, 18 subassociations, 8 variants and 5 facies are distinguished. A series of associations belong to 13 alliances, 12 orders and 9 classes which were described earlier (some of them are provisional). The procedure of classification have showed some methodical difficulties. One of them is the revealing of belonging syntaxa to any class, a lot of which were described in more south regions. As a result much of diagnostic species of these classes are absent in arctic regions. So far as many species of Arctic characterized by wide distribution they cannot be used as character species. The concept of vicariant syntaxa is used: 5 associations are considered as vicariants of syntaxa already distinguished. At present there are not any higher syntaxa (class) for correct description for zonal (plakor) vegetation, erect shrubs and zoogenic vegetation in arctic tundra subzone. The syntaxa of CaricirupestrisKobresieteabellardii and Thlaspietearotundifolii predominate in island. There are north limits of areas of some syntaxa such as ass. SphagnoEriophoretum vaginati vic. Polytrichastrum alpinum, Brachythecio salebrosiSalicetum glaucae, Parryo nudicaulisSalicetum lanatae, Equisetetum borealis vic. Polemonium acutiflorum on Wrangel Island. Zonal associations are characterized by lowest number of character species (24). The reason of this phenomena is the average meaning of ecological parameters in plakors. As a consequence many species of different ecological groups can growth together. There are fr om 9 to 17 character species in some intrazonal associations: Carici membranaceaeDryadetum integrifoliae, Castillejo elegantisCaricetum rupestris, Salici callicarpaeaDryadetumchamissonis, ArtemisioborealisChamaenerietumlatifolii.

Following associations of plakor are characterized by the highest species richness: ParryonudicaulisDryadetumpunctatae (255 taxa) and ArtemisiotilesiiDeschampsietumborealis (250). Besides these the ass. SalicipolarisCaricetumpodocarpae which is formed in snowbed sites have 251 taxa. A lot of species have middle (III) or low (II, I) constancy. The higher number of species in syntaxa compared to community is due to rare species.

The coverage of majority of species varies from <1% to 5%, not more than 10 species from 6% to 12%. Only 3 species form an stable coverage more than 25%: Carexlugens, Dryaspunctata, D.integrifolia. Two types of community are characterized by the homogeneous cover: ass. MeesiotriquetrisCaricetumstantis vic. Warnstorfiasarmentosa and ass. SalicipolarisCaricetumpodocarpae. The tundra turf is heterogeneous in zonal (plakor) communities. It consists of different fragments of mosses, lichens and vascular plants. Frost boils (patches) are most common elements of horizontal structure. The turf around patches forms continuous net. Non closed (open) communities are predominate at all slopes, tops and mountain terraces. Cushions formed by herbs Artemisiaborealis subsp. richardsoniana, A.glomerata, Oxytropisgorodkovii, Potentillasubvahliana are usual in such sites. There are 2 layers in communities: an upper one (1030 cm) wh ere herbs are predominate and dwarf shrubs-lichen-moss (less than 10 cm). The height of shrub Salixlanata subsp. richardsonii layer at the center of island is 4560 cm.

Key words: arctic tundras, classification, syntaxa, association, Wrangel Island

Section: Articles

How to cite

Kholod S. S. 2007. Classifiction of Wrangel Island vegetation // Vegetation of Russia. N 11. P. 3135.

Received February 27 2004