ИСТИНА

A spatially explicit individual-based model was developed for the population dynamics of the endangered Arctic fox on Mednyi Island. The model is based on field data collected during 19 years. Annual marking of cubs allowed us to identify up to 80% of animals individually and to collect their life-history data. We determined mortality rates of males and females of all age classes, sex ratios for each age class, probabilities of breeding and litter sizes. In addition, we mapped social structures, dispersal distances, and patterns of selection of social partners and habitat patches. The model is spatially explicit, i.e., heterogeneity of habitat patches is defined in an explicit form. In simulations, such demographic parameters as population dynamics, population age structure, sex ratio in different age classes, and structure and size of families conformed to the empirical data. The analysis of the model sensitivity to changes in mortality rates in different age classes showed that the sensitivity to increased mortality of cubs is much higher compared to adults of all age classes. Increasing the cub mortality rate to 95% over a period of one to five years, we simulated the effect of an otodectic mange epizootic, which was observed in the real population of Mednyi Arctic fox. The population recovery time after the end of the impact was significantly longer in the simulations compared to the field data. We suggest that in reality, with a low population size, the productivity of the population increases, and the mortality of cubs may decrease.