Аннотация:Zonal ecotones of Inner Asia formed by biogeographically specific communities of conti-nental birch and larch forest-steppes and by dwarf semi shrub – bunch grass and feather grass com-munities of semi-deserts that have no analogs in other regions. Regional biocoenotic complexes of flora and fauna existing in these conditions distinguished not only by increased diversity but also by the antiquity of origin, high integrity and uniqueness. These features are necessary to take into ac-count in the evaluation and conservation of biological diversity.