To the Ecology of Species-Double of Common Vole (Microtus arvalis, Pall.) at the Northern Limit of the Range

Based on long-term expeditionary and stationary studies in the taiga Northwest of Russia, the features of distribution, biotopic distribution, reproduction, population dynamics and other ecological features of the common voles are characterized, including those associated with its habitat at the northern boundaries of the range. It is established that in the past fiftieth anniversary the northern boundary of its distribution first moved to the north and reached 63°40′ s. and then also quickly retreated to the south. The reason for the latter is a sharp reduction in crop areas, primarily cereals, in connection with the reorientation of agriculture to dairy and vegetable. This, as well as the replacement of the common voles by native rodent species (housekeeper, dark and red-breasted voles) caused a sharp decrease in the abundance and narrowing of the species range in the eastern regions of Fennoscandia. In the taiga Northwest of Russia during the snowless period, the common voles live primarily in open habitats, including horticultural plots, and in winter they concentrate in haystacks and in straw stacks, where they live together with other representatives of the Microtus. According to V.V. Gromov [2008] and our observations, the elementary structural unit in the settlements of the common voles, is a family group occupying a limited habitat that has been in operation for a fairly long time. In the diet, the main role is played by the participation of herbaceous plants (72% of the occurrence), the smaller – seeds (25%) and a very rare component – tree bark (3%). Under the conditions of the northern periphery, the range reproduces only during one, rather limited, spring-summer season. The age and sex composition of the population varies by season.