Analysis of spatial intra-population organization of small mammals using the gradient approach and multidimensional scaling

We demonstrate the possibilities of the nonparametric multidimensional scaling method for studying the spatial intra-population organization of small mammals on the example of the bank vole (Myodes glareolus, Schreber) from the indigenous ecosystems of the Central Forest Biosphere Reserve (Russia, Tver Region). The studies were carried out in the second half of the breeding season, when the population of the species is characterized by a high total number and a rather complex demographic structure. On the basis of the functional- ontogenetic approach, three intra-population groups were distinguished: sexually mature this year’s brood (mature individuals that reproduce in the year of birth, characterized by single-phase growth - the first type of ontogenesis); immature this year’s brood (immature and non-breeding individuals in the year of birth with two-phase growth - the second type of ontogenesis, the first phase); overwintered animals (second type of ontogenesis, second phase). It was shown that in the second half of the reproductive period, a specific spatial intra-population structure is formed in the bank vole, which is primarily due to the peculiarities of relations between animals of various functional and ontogenetic groups. The studied groups of bank voles are confined to different areas of the ecological space. For some groups of individuals, a rather pronounced spatial differentiation was noted, for others - a significant degree of overlap. The revealed features of the spatial intra-population relationships of the bank vole can be one of the mechanisms for ensuring the age cross, which plays a significant role in population dynamics, primarily to maintain and increase the heterogeneity of the population.