Herpetofaunistic Zoning of Northern Eurasia
For the purpose of zoning with respect to the fauna of Amphibia and Reptiles, Northern Eurasia within the boundaries of the USSR in 1990 was separated into 245 regions over the vegetation map scaled 1 : 20 000 000 so that each region occupied the territory of natural sub-zone extended by 10 in the longitudinаl direction. For each region, a list of species met there was compiled over the natural habitats of Amphibia and Reptiles. Using these lists, we calculated the Jacquard quotients of similarity and performed the cluster analysis of the herpetofauna of the allotted regions. On the basis of these results, a hierarchical classification was arranged. It includes 3 herpetofaunistic regions divided into 5 subregions; some of them are further divided into 13 provinces; some of the latter are divided into 32 districts. Environmental factors correlating with the faunistic heterogeneity of the territory under investigation were revealed. The proposed division is 2-4 times more informative than the previously developed schemes and takes into account 73 % of the dispersion of similarity coefficients for the faunas of specific regions (the coefficient of multiple correlation is 0.85). Connection with environmental factors and natural regimes may explain 84 % of the fauna heterogeneity (correlation coefficient is 0.92).