THE PROBLEM OF ECOTONES IN ZOOGEOGRAPHY ( A REVIEW OF RUSSIAN LITERATURE)

Analysis of zoogeographic studies in the main <<intermediate>> zones o f the North Eurasia (forest tundra, forest steppe, semidesert) as well as between the North and South Turan deserts, in the foothills and in trazonal regions allowed to reveal the differences in faunistic descri ptions. Absence of clear-cut terminology and quantitative data makes d eterminations of <<ecotones>> and their boundaries difficult. Preserva tion of biodiversity requires further studies of these problems.