Abstract
The paper deals with the study of species composition and small mammals population structure of Malaya Sosva (Little Sosva) state nature reserve, Khanty-Mansi Autonomous Okrug Yugra, Russia. The research was conducted within the last ten days of June, 2019 on the Malaya Sosva River flood plain (Shukhtungort ranger station neighborhood, northern taiga). The animals were registered in typical biotopes of the research area: a herb-oxalis pinery, a lingonberry-lidum pinery, a lingonberry-pleurocarpous moss pinery, a herb-oxalis spruce forest, a herb-woodreed pinery, on the skirts of a mixed forest around the ranger station on the border of a mowed secondary meadow. In the course of investigation, the following five species of small rodents and insectivores were registered: Myodes rutilus, Myodes rufocanus, Sorex caecutiens, Talpa europaea, Pteromys volans. M. rutilus was an absolute dominant species in terms of numbers in the majority of the studied biotopes. S. caecutiens is co-dominating in the herb-oxalis pinery and herb-oxalis spruce forest, and M. rufocanus is co-dominating in the lingonberry-lidum pinery. In the herb-woodreed pinery, only individuals of S. caecutiens species were caught in a pitfall trap. Communities of small mammals in different types of habitats show low values of species diversity and sustainability due to harsh natural-climatic conditions of the region. A small mammals community of mature herb-oxalis pinery on the bank of Svyatoy Sor Lake, where the protected species, Pteromys volans, was registered, shows the highest values of abundance of small mammals and a maximum level of overall welfare index. It suggests that the habitat under study should be studied further and protected.