About some features of steppe communities of the Amalat river basin (Northern Transbaikalia)

Abstract

The Vitim upland, in the central part of which the Amalat River basin is located, is still one of the least studied floristically areas of Northern Transbaikalia. The flora of the steppe areas (uburs) in this territory still remains unexplored. The study of the flora by the method of specific floras and the identification of diagnostic groups of species in the analysis of geobotanical descriptions using the IBIS program made it possible to identify the features of the steppe communities of the Amalat River basin. It has been established that in the studied territory the uburs are small fragments of steppes (up to 5 hectares) on steep (15-35 °) slopes of southern exposures; the largest area is occupied by steppe communities on the left bank of the river. Quite peculiar steppe communities have been found on carbonates in the upper reaches of the Klyuch Berezovyi, Bagdarinka, Khoigot and other rivers. The flora of the studied steppes is represented by 47 families, 104 genera, and 177 species. An analysis of its arealogical structure showed that boreal species form the basis of the flora of the studied steppe communities, and the combination of species with the South Siberian, North Asian, and Manchurian-Daurian ranges determines its originality. The study of the belt-zonal structure showed a natural predominance of species of the steppe floristic complex (57%), the overwhelming majority of which are mountain-steppe and forest-steppe species; the proportion of steppe species proper is insignificant (9%). The ecological-biomorphological structure is characterized by the prevalence of perennials.