PHYTOCOENOTICAL BEHAVIOUR OF ARCTIC AND ARCTIC-ALPINE PLANT SPECIES IN BOREAL-FOREST ZONE COMMUNITIES OF EUROPEAN RUSSIA
I.B. Kucherov1, A.A. Zverev2,3, S.V. Chinenko1
1V.L. Komarov Botanical Institute RAS, St. Petersburg, Russia
2Tomsk National Research State University, Tomsk, Russia
3Central Siberian Botanical Garden SB RAS, Novosibirsk, Russia
Keywords: arctic floristical element, arctic-alpine floristical element, European Russia, history of flora and vegetation, dark-coniferous forests, southern hypoarctic tundras
Abstract
Phytocoenotical behaviour of 21 arctic-alpine and arctic vascular plant species is analyzed in different subzones of the taiga zone in comparison with that in tundras, based upon the set of 2234 relevés made in European Russia in 1996-2007 (see Table 2; Figure). Species prefer rich (mainly carbonate or sulfate) but cold soil in the taiga zone of European Russia. The climate continentality regime affects them less valuably, although the affiliation of some species to different bedrock types may depend on the area longitudinal position. Many arctic-alpine species occur under the canopy of light-coniferous forests on limestone or gypsum but only in treeless communities on silicate bedrock. The main part of the arctic species is restricted to salinized seashore soils. The three floristic elements are distinguished within the arctic fraction of a taiga zone flora, namely the periglacial-karst (the Dryas flora core in the Late Pleistocene), the maritime, and the mire-riverside ones, with several subelements each. Both the ecological and phytocoenotical differences between species and the historical-climatical events which caused different waves of migration lead to species subdivision into elements and subelements. Those of the periglacial-karst element are distinguished according to species occurrence on limestone and gypsum outcrops only (the karst subelement with Dryas octopetala, D. punctata, Salix reticulata etc.) or on silicate rock (the rock subelement with Saxifraga spp.), in low-herb meadows (the rock-meadow subelement with Poa alpina), or in Scots pine forests on sand (the rock-redwood element with Arctous alpina and Oxytropis sordida) as well. The arctic-alpine species which migrated in the Middle and/or Late Dryas and then in the second half of the Praeboreal comprise the bulk of the element. Subelements of the maritime element are defined according to species affinity to either littoral (Carex subspathacea) or supra-littoral (C. glareosa) belts, or maritime crowberry heath (Loiseleuria procumbens), also according to species oceanicity/continentality which determined the vectors of their migration. The arctic species which migrated in the Middle Dryas and then in the Little Ice Age prevail. Subelements of the mire-riverside element are distinguished according to species affinity to mires of different mineral richness (Carex rariflora, Tofieldia pusilla) or to silt/gravel banks (Caltha arctica, Arctophila fulva). The Upper Pechora riverside subelement comprises the arctic hygrophytes and probably has the Riss-Würm interglacial or Early Würm glacial origins. In the meantime, the arctic-alpine Eriophorum scheuchzeri (the mire-riverside subelement) continues migrating nowadays.
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