About some discussion issues on steppe typology and florocenotypes related to them in vegetation of South Siberia

Abstract

The phytogeographic ecotonicity of Southern Siberia (SS) is reflected in the features of its flora and vegetation, in particular the steppes. The recognition of only a floristic criterion in the typology of vegetation impoverishestheir real cenotic diversity. It is necessary to accept the florocenogenetic concept with fractional landscape-biomorphological types – florocoenotypes in the spirit of P. N. Ovchinnikov. By the genesis, the most ancient are the zonal sod grass(feather grass) steppes. However, the initial should be considered the Achnatherums and, in general, the communities ofshort-awned great-feather grass (Tsvelev, 1977), which formed steppe groups in the Tertiary savannoid complexes. Theformation of mountain cereal steppes – with fescue, oat, bluegrass, etc. took place synchronously with cryoxerophytization, starting from the Oligocene. The originality of the SS steppes is given by some rare steppe communities, which arecoenogenetically close to the tragacanth, friganoid, shiblyak and ephemeral steppes of mountainous Central Asia. Theseare distinctive relict steppes in the belt of the Altai, Sayan and Transbaikal mountains, which include communities of viviparous grassland steppes in the foothills of Western Altai, tragacanth-oxytropis steppes of southeastern Altai, and communities of the Tuvan and Daurian shiblyak, as well as groups of Altai friganoids with Ziziphora clinopodioides, Thymusaltaicus and Allium pallasii.