The history of formation of recent small mammal communities in the Nether-Polar Urals.

The results of studies on small mammal bone assemblages from seven cave-type sites on the Shchugor and Kozhim rivers are presented. Four stages in the development of small mammal fauna in the Nether-Polar Urals are described, which correspond to the Alleröd, Younger Dryas, Early Holocene, and Subatlantic periods. The moderately cryohydrophilic fauna of the Alleröd was replaced by an atypically 'mild' xerophylic community in the Younger Dryas. In the Early Holocene, its structure still included considerable proportions of tundra species, which, along with forest species, were also found in the subfossil assemblage from the Subatlantic. It is shown that the transformation of the small mammal fauna in the above sites had a specific pattern, compared to that in other regions of northeastern Europe and to the dynamics of the natural environment and climate. [ABSTRACT FROM AUTHOR]