Peculiarities of trophic relations of rodent populations in case of change of survival strategy

Continuous 50-year observations of rodent populations in the Kaniv Nature Reserve (Cherkasy region, Ukraine) have revealed a violation of trophic relations due to anthropogenic influences. Field observations were carried out during the first half of summer every year. The background species of forest habitats of the reserve are three species of rodents – bank vole (Myodes glareolus), pine vole (Microtus subterraneus) and yellow-necked wood mouse (Sylvaemus flavicollis). The research period covered various stages of the existence of the protected ecosystem. The small area, location in the densely populated region of Ukraine, interaction with neighboring territories, which are involved in economic activities, have always caused anthropogenic pressure on the protected area. Its nature and intensity determined the changes in the protection regime and the elimination of the status of the reserve in 1951–1968. Later, the territory of the reserve experienced increasing technogenic pressure, to which radioactive contamination was added. In this work, to compare their characteristics, four complete cycles of the density dynamics of the rodent populations (from depression to depression) were selected, the duration of which was 4–5 years. The first three cycles correspond to qualitatively different periods in the existence of the ecosystem and the populations of the studied species, and the last one corresponds to the relatively current situation. It was found that the interdependencies in the "population – feed base" system existing in the first two decades are disappearing and have not been restored for the last 30 years. This is accompanied by such phenomena as the reduction of the total biomass of rodents, shrinking the size of individuals and the intensification of reproduction. It has been established that in this period, the quantitative and qualitative
indicators of the rodent feed base remain almost unchanged, but the relationship with the dynamics of population density is disrupted. It is proved that the condition of the feed base by itself cannot cause shrinking. It has been suggested that the degradation of individuals against a background of stable trophic conditions is a specific population strategy for maintaining an ecological balance. It predicts that the population reduces the share of energy to maintain biomass of its own elements in order to reduce aggregate costs or release resources for further intensification of reproduction.

Мякушко С.А. Особливості трофічних звязків популяцій гризунів у разі зміни стратегії виживання. Екологічні науки. 2022. № 1(40). С. 55-61. DOI https://doi.org/10.32846/2306-9716/2022.eco.1-40.10