POPULATION DYNAMICS OF THE RED-BACKED VOLES (CLETHRIONOMYS) IN THE UPPER KOLYMA RIVER (THE BUYUNDA RIVER)
For the first time a long-term monitoring (2002-2010) of population dynamics and variability of demographic parameters of red-backed voles of two species, northern red-backed vole (Clethrionomys rutilus Pallas, 1779) and grey-sided vole (Clethrionomys rifocanus Sundevall, 1846), has been conducted in the upper reaches of the Kolyma (the Buyunda R.). Phases of population depression, growth and peak changed successively and synchronously in both species, forming a complete 3-year cycle. Important regulators of the population number were winter surviving and the yearling degree of participation in breeding. Other demographic parameters (duration of the reproductive period, breeding performance, sex-and-age-related structure of population) also influenced the number of animals, but did not significantly change the cycle structure. Of the external factors regulating the red-backed voles mortality, the under-snow climatic conditions of the winter period was of great importance. In general, the population dynamics is similar to that in the Northern Priokhotie and significantly differs from other regions of the continental Northeast Siberia, studied earlier, by higher parameters.