The population of small mammals in the eastern part of the Middle Timan
Landscape heterogeneity of the territory is an important factor in the formation of population structure of small mammals. In this respect, the northern taiga of the Middle Timan is of great interest, as the habitats here are specific types that are missing in other areas of the European North. In addition, this region has never conducted research on small mammals, so our data are the first on the population structure of this group of animals. We conducted studies in the eastern part of the Middle Timan in the middle reaches of the Pechorskaya Pizhma river (64°53'N, 51 °28'E) from 2014 to 2016. A large area is occupied by spruce wet; in the river valley grow birch forests and meadows. We assessed the number of animals using 50-meter catching grooves, in the bottom of which five cones were dug. During the third week of August annually, we opened five grooves in four different habitats for 10 days. The number of small animals caught in 10 days was taken as a record indicator (ind./10 groove-days). We noted 14 species of shrews and voles. The total number of small mammals is relatively minor - 35.0 ind./ 10 groove-days. It is not very different from the respective figures for the northern European taiga. The basis of the population is constituted by three species - Sorex caecutins (28.7%), S. araneus (20.9%) and Myodes rutilus (17.3%). Their abundance indices exceeded 6 ind./10 groove-days. Common species here are Microtus (14.4%), among whichMicrotus oeconomus is quite numerous. The number of Sorex minutus, Myodes glareolus and Sicista betulina is insignificant (1-2 ind./ 10 groove-days). The rare species (less than 1% of catches) are Sorex tundrensis, S. minutissimus, Myopus schisticolor. For them, the region is the area periphery. The number and proportion of small mammal species differed in their habitats. We observed the maximum abundance in high-grass birch forests (47.0 ind.), the minimum - in moss birch forests (27.2 ind./10 groove-days). In moss spruce fir forests and in meadows these indices were close and made respectively 39.2 and 37.7 ind. /10 groove-days. In fir groves and moss birch forests shrews (61.3-76.1%) prevailed in catches. Among them, three species of S. caecutiens, M. rutilus and S. araneus dominated, Microtus being rare. Only in these habitats Myopus schisticolor was encountered. In grassy biotopes the significance of shrews decreased, they made less than a half of catches (45.7-46.9%). Here, the share of gray voles increased. In high-grass birch forests the first two places were divided by M. rutilus (26.6%) and S. araneus (25.5%). The third place was taken by Microtus agrestis (11.7%), while the fourth - by S.caecutins (10.6%). S. isodon was also typical (6.4%). In meadows,Microtus oeconomus (28.3%), S. araneus (25.6%) and S. caecutins (11.5%) dominated. The share of forest voles was minimum (8.0%), and the abundance of Sicista betulina (8.0%) was the highest among habitats. The article contains 3 Figures, 2 Tables, 28 References.