The arctic-alpine elements in the alpine flora of Altai

Abstract

In continuation of A. I. Tolmachev’s ideas on the need for the special study of Arctic-alpine component in high-altitude floras, the group of Arctic-alpine species has been identified in the Altai high-altitude flora. By utilizing the methods of floristic analysis, the features of the taxonomic composition of the Arctic-alpine species group, the proportion of the ecological groups of species in relation to humidity and the nature of substrate, the role of climatic and choro-logical groups of species in the formation of the complex of the Arctic-alpine species have been shown. For the first time, the comparative analysis of the Arctic-alpine species groups in high-altitude and arctic floras was performed with the use of the Jaccard similarity coefficient and measures of inclusion. The main stages of the Arctic-alpine groups’ formation in various Siberian floras have been revealed. It is expected that the formation of the core of the complex of arctic high-alti-tude species, in Siberia, took place at the end of the Pleistocene - beginning of the Holocene. Subsequent recruitment of the Arctic-alpine species group was occurring in the hypoarctic floras in northeastern Siberia due to climate change in the Holocene. The distribution features of the Arctic-alpine species from Southern Siberia to the mountain systems of Mongolia have been shown. 3 groups of botanical and geographical regions of Mongolia have been designated according to the representativity of Arctic-alpine species, the sources and ways of Arctic-alpine species’ distribution in Mongolia have been shown.