Strand’s Birch Mouse Sicista strandi (Rodentia, Dipodoidea) on the Southwestern Periphery of the Species Range: Genetic and Ecological Aspects

Based on study of the nucleotide sequences of the nuclear DNA IRBP gene fragment in the population of Sicista strandi from the southwestern periphery of the species range (mountainous Caucasus, vicinity of the Ekiptsoko cordon, Zolskii district of Kabardino-Balkaria, adjacent territory to the terra typica of the species) and their comparison with molecular characteristics in representatives of the species from a number of points on the Russian Plain, its position in the species structure was studied for the first time. It was established that, according to this molecular trait, the studied Caucasian population belongs to the southern group of the species, which, in addition to the Caucasus, includes samples from the basins of the Lower (Rostov oblast) and Middle (Lugansk oblast) Don and presumably from the Lower Volga region, differing from the samples from the northern parts of the species range in the Central Chernozem region (Kursk and Belgorod oblasts). A number of ecological and biological characteristics (biotopic confinement, population composition, number, daily activity, seasonal activity, reproduction, nutrition), considered in a comparative aspect due to genetic differentiation of the species, were studied for the first time in the population of S. strandi from the southwestern periphery of the species range.