East urals radioactive trace: Adaptive strategy of rodents’ population

Institute of Plant & Animal Ecology, RAS Ural Branch, 8 Marta Str., 202, 620144 Ekaterinburg, Russia

Abstract

Population of small rodents in radiocontaminated environment is compelled to include more energy-intensive way of maintenance its ability to live — increasing of the proportion of mature young of the year (first pathway of ontogeny). Their reproductive characteristics — actual fecundity was higher, whereas embryonic mortality and the proportion of females with embryonic losses were significantly lower compared with neighboring areas. Abundance of mice in the impact zone was higher, age cross was revealed, which improves the adaptive possibility of the population. Preconditions for acceleration of evolutionary transformations of a population are created, but this process is restrained by both the local configuration of the polluted territory and migration of murine rodents. As a consequence, the population decreases the probability that certain changes will be fixed and inherited in a series of generations. Chronic low-dose radiation (stress) can be considered as the mechanism of switching of life history of cyclomorphic mammals. Thus, ontogenetic multiversality of small mammals is an important mechanism of protection strategy of population and decreasing the damaging action on biota in radiocontaminated environment. Functional approach makes it possible to reduce errors in assessing the radiological consequences and hence, can provide a reliable methodological basis for organization of biological monitoring.