The geographical parallels of lithoreophil communities organisation in small streams of Eastern Europe and Northern Asia.

The influence of geographical position on taxonomical composition and structure of communities inhabited stony riffles is consideed on a material from 79 small streams situated in four regions of Eastern Europe (Moscow region, Southern Ural, Northern Caucasus and Mountain Crimea), as well as on publishing data on Asia and Northern Ural regions. Litoreophil communities of mentioned regions include different but closely allied species with similar habits. Eight basic living forms of litoreophils are common practically everywhere irrespective of geographical position and taxonomical composition of the community. The average number of species in a sample is also constant and includes 13-14 species. Local relief and climate influence the abundance of living forms and species diversity.