While performing studies we imposed the tasks to reveal general (background) characteristics of structural-dynamic organization of the vegetation and to find out the peculiarities of formation of phytocoenoses on the sites reflecting the specifics and trends of their modern formation under anthropogenic impact, such as fires, cutting and pasturage during several decades. The studied area is situated in the transitional zone between the forest-steppe and zonal steppes characteristic for South-East Asia – i.e., in an interzonal ecotone. An interzonal ecotone consists of coenoses forming under transitional environmental conditions, in this case – between forest-steppe and steppe areas of North and Central Asia. Main attention was paid to the characteristics of the actual state of phytocoenoses forming under different conditions of their recent destructions; species composition of synfolia and the most characteristic proxy species determining the actual state and the vector of formation of steppe coenoses and forests during last decades were studied with a particular attention. While analyzing the data obtained, we took into account as well the characteristics of the vegetation structure in the studied area presented in published papers of numerous researchers for many years. The results of general studies of the Baikal Region vegetation were also taken into account. The interzonal ecotone itself including the area of our studies always reflects spatial-dynamic organization of vegetation in the environmental zones in time and space. Anthropogenic factors are increase of the spatial and structural difference of the plant communities of the environmental contact all time.

Sizykh Alexander Petrovich, Doctor of Science (Biology), Leading Researcher, Laboratory of Ecosystems Bioindication, Siberian Institute of Plant Physiology and Biochemistry SB RAS, 132, Lermontov st., Irkutsk, 664003, Russian Fedeartion, e-mail: alexander.sizykh@gmail.com

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