Late Holocene small mammals from localities of Sharyu river valley (Chernyshev's ridge)

The Holocene history of small mammal fauna is of interest as an example of transformation of communities under the natural changes of climate. Study object were 2720 molars of small mammals from localities in Sharyu River valley (left tributary of Usa River). Molars were studied by standard palaeontological techniques. 14C AMS method was used for dating of fossil assemblages. All localities are zoogenic sites with abundant fossil remains of vertebrates. In the result, two phases of micromammalian fauna development in the Chernyshev's Ridge are described: Subatlantic and modern periods. It was revealed that typical taiga forest assemblages of small mammals inhabited the Chernyshev's Ridge during Subatlantic time. This fauna was nearly identical to micromammalian communities of the same interval in the Subpolar Urals but contrasted to tundra assemblages of the eastern slope of the Polar Urals. Species composition differences between Sharyu-2 and Sharyu-3 were caused by the hunting activity of different species of avian predators (diurnal raptors and owls). Alternations between recent micromammalian assemblages of the Chernyshev's Ridge and communities of adjacent territories are linked to differences in taphonomy.