Biodiversity and Geography of the Boreal Mountain Forests of the Northern Baikal Region.

Biodiversity geography is now rapidly successfully developed within general biogeography, encompassing many aspects of biota differentiation on various levels of the biotic cover organization. This study concerns the biodiversity geography from the standpoint of the basic classification of terrestrial ecosystems, utilizing an ecological–geographical approach to interpret their biodiversity; it substantiates regional orobiomes as basic units for assessing the species and ecosystem diversity of mountains. The purpose of this study is to identify the regional specifics of typological diversity of mountain forest ecosystems and biota in connection with the altitudinal-belt structure and altitudinal gradients and to determine their role in the organization of mountain space with respect to its ecotopic structure. To achieve the purpose, statistical methods for processing digital cartographic models of vegetation, relief, and climatic conditions are used. The altitudinal-belt structure of the plant cover was revealed by the example of the Northeast-Transbaikalian taiga orobiome. The spatial structure of the mountain taiga belt, reflecting its typological diversity, was revealed on the basis of a small-scale map of orobiome forests. The mountain taiga belt (with two subbelts) determines the regional specificity of the floristic and cenotic diversity of East Siberian mountain forests of the orobiome. Larch forests predominate in the forest cover of the belt, pine and dark coniferous forests take a limited part, and the species composition decreases along the altitudinal gradient. Along with the features common for the orobiome, there are also specific features of forest biodiversity in its geographical variants associated with different ratios of typological units at different altitudinal levels. The key parameters of heat and moisture supply of high-altitude belts are determined for the mountain taiga belt; they characterize the climatic conditions for the biodiversity formation in the mountains of the Northern Transbaikalia. The successful use of orobiomes in the analysis of biodiversity of the mountain areas determines the prospects for studying forests and for developing a system for their monitoring and protection on a single biome basis. [ABSTRACT FROM AUTHOR]