Vegetation of the middle reaches of Yakhadiyaha river (the southern part of the arctic tundras of Yamal peninsula)

Abstract

For the first time a syntaxonomical diversity was determined for the arctic tundra of Yamal. In total, 6 associations, 3 subassociations and 5 communities that belong to 5 classes, 5 orders and 6 alliances were revealed for the northern part of the peninsula. From them, 1 association and 3 subassociations are new. The association Dactylino arcticae–Racomitrietum lanuginosi ass. nova hoc loco was attributed to the alliance Loiseleurio–Diapension, order Rhododendro–Vaccinietalia, and class Loiseleurio–Vaccinietea. The communities are confined to the drained above-floodplain lake terraces and shoulders, the convex parts of slopes with slight inclination. Subassociation Antennario lanatae–Arctoetum alpinae lagotoetosum minoris subass. nova hoc loco was included in the alliance Oxytropido sordidae–Tanacetion bipinnati, order Androsacetalia alpinae, and class Thlaspietea rotundifolii. The coenoses are characteristic for eroded deflation slopes. The soils are weakly developed on sandy ground. Herbs, mosses and lichens predominate in the communities. The subassociations Aulacomnio turgidi–Eriophoretum angustifolii сladonietosum bellidiflorae subass. nova hoc loco and Aulacomnio turgidi–Eriophoretum angustifolii bistortetosum viviparae subass. nova hoc loco were attributed to the alliance Carici concoloris–Aulacomnion turgidi, order Rhododendro–Vaccinietalia, and class Loiseleurio–Vaccinietea. The communities of subassociation Aulacomnio turgidi–Eriophoretum angustifolii сladonietosum bellidiflorae subass. nova hoc loco are the elements of tundra-bog complexes occupying flattened river terraces above floodplain and flat watersheds. The coenoses of subassociation Aulacomnio turgidi–Eriophoretum angustifolii bistortetosum viviparae subass. nova hoc loco are characteristic for flattened parts of watersheds, sometimes with slight inclination, as well as for flat surfaces of river and lake terraces.