Author(s)

A.P. SIZYKH

Abstract

By monitoring the spatial–coenotic changes of taiga–steppe communities and fluctuations of climatic factors over the course of many years, it was possible to identify dynamic trends of the region’s taiga–steppe ecosystems’ formation. The layered character is most clearly pronounced, where meadow–steppe and forest–steppe plant species become predominant, irrespective of the type of habitat of the communities. The composition of taiga–steppe (transitional between forest and steppe) ecosystems reveals a spatial spreading of sinuosities of mosses characteristic for the light-coniferous and for the dark-coniferous taiga. A special trait of the spatial changes in the region’s vegetation structure should be mentioned, namely, a tendency toward a very active intrusion of wood species: pine and larch, into steppe communities thus forming curtains of uneven-age trees ranging from shoots to 25- to 30-year trees. Isolated (amidst steppes) trees as old as 40–50 years were reported previously. Processes of overall mesophytization and aforestation of steppes were observed throughout the western shore are of Lake Baikal. The genesis of the region’s vegetation over the course of Holocene and modern tendencies of the communities at the background of the changes of temperature–hydrological regimes over the last several decades suggest the initial stage of formation here of taiga–steppe ecosystems characteristic only for this region of east Siberia.

Keywords

coenoses, extrazonal stepoides, Lake Baikal, protection, taiga–steppe ecosystems