Dynamics of the mouse-like rodents in the southern part of the forest area of Primorskaya state academy of agriculture in 2019-2020
The article presents data on the results of a study of the small mammals number in the southern part of the forest area of Primorskaya State Academy of Agriculture in the spring-summer period of 2019 and 2020. The catching was carried out according to the standard method with Gero-type break-back traps. During two seasons, 87 animals belonging to 7 species of rodents and insectivores were caught. During these years, the population of mouse-like rodents in the forest area of the Primorskaya State Academy of Agriculture seems to be in a state of depression: the total number of rodents was only 6.2 ind./100 trap-nights in 2019 and 7.0 ind./100 trap-nights in 2020. The grey red-backed vole and the Korean field mouse were dominant in different forest communities, while the relative number of the latter species decreased by 3.5 times in 2020 compared to 2019 in one of the biotopes. This can be explained both by the dependence of the Korean field mouse population on the yield of seed feeds, primarily Korean pine nuts and Mongolian oak acorns, and by the higher mortality of mice in winter than in the grey red-backed vole. The number of grey red-backed vole remained at the same level, what is explained by a more stable food base of this rodent (vegetative parts of plants). From 82% in 2019 to 100% in 2020 of small mammals species composition in the forest nursery of the Primorskaya State Academy of Agriculture was a striped field mouse, what is typical for human-disturbed biotopes. In the valley broad-leaved forest adjacent to the nursery, the number of the striped field mice was also high; this rodent was in the second place after the Korean field mouse. Probably, the forest nursery is the core of the striped field mouse population and serves as a source of penetration of these rodents into the nearby forests. Thus, the role of the striped field mouse as an indicator of the digression of the state of natural communities during their transformation by human economic activity was proved. The low number of mouse-like rodents also affected the state of Mustelidae population, primarily sable. Although we did not carry out special sable density estimation, during winter excursions it was noted that in the winter of 2019/20, sable tracks were regularly found even in unusual biotopes, such as oak and ash forest, and in the winter of 2020/21, no sable tracks were found at all. In the future, we plan to continue our research to identify the complete cyclicity of the mouse-like rodents number dynamics in the forest area of the Primorskaya State Academy of Agriculture, as well as to identify the relationship of the dynamics with various factors such as climate, seed yield of tree species, etc.