Ecological-evolutionary mechanisms of biodiversity formation in the mountains: An example of Caucasian mammals

Trends in the altitudinal and sectoral structural variation of ecosystems in mountain areas are considered using an example of mammals as an important component of ecosystems. With consideration of the environment-forming ecogeographic factors, a hierarchical system of taxa reflecting the altitudinal zonal structure of ecosystems of mountain landscapes is proposed. The system includes six categories: (1) mountain ecosystem kingdom; (2) mountain land; (3) cohort of zonality types; (4) zonality type; (5) zonality subtype; and (6) variant of zonality. As a model of the mountain land taxon as a subunit of the mountain ecosystem kingdom, the therio-fauna of the Caucasus is considered. The Caucasus is a unique mountain land where two cohorts of zonality types, five zonality types, two zonality subtypes, and 14 zonality variants are well defined. It is shown that the contribution of landscape sectoral heterogeneity to the formation of biological diversity in mountain territories is more substantial than that of altitudinal heterogeneity. The altitudinal zonality of mountain landscapes plays the role of a "matrix" of the variation of biological systems at all levels of living matter organization.