AN INDIVIDUAL-BASED MODEL OF THE POPULATION DYNAMICS OF THE ARCTIC FOX (VULPES LAGOPUS SEMENOVI) ON MEDNYI ISLAND, COMMANDER ISLANDS, NORTH PACIFIC

Authored by E D Sushko, M E Goltsman, L O Doronina, E P Kruchenkova

Date Published: 2018

DOI: 10.1134/s0044513418110041

Sponsors: No sponsors listed

Platforms: AnyLogic

Model Documentation: Other Narrative Flow charts

Model Code URLs: Model code not found

Abstract

We develop a spatially explicit individual-based model which imitates the population dynamics of the Arctic fox on Mednyi Island. In the Red Data Book of the Russian Federation, the Mednyi Arctic fox is listed as an endangered species. The developed model is based on data collected during 19 years of fieldwork. Annual marking of cubs in the study area allowed us to identify up to 80\% of animals individually and to collect their life-history data. As a result, we identify the mortality rates of males and females of all age groups, the probabilities of breeding, litter sizes, the sex ratios of animals in different age classes, social structures, dispersal distances, and the patterns of making decisions in the selection of social partners and habitat patches. The model is spatially explicit, i.e., the heterogeneity of the habitat patches is defined in an explicit form. The model works with a time step of one year. In simulations, such demographic parameters as population dynamics, population age structure, sex ratio in different age classes, and the structure and size of families conformed to the empirical data. An analysis of the model sensitivity to the variations of mortality rates in different age groups showed that the sensitivity to the shift of cubs' mortality is much higher compared to adults of all age classes. Through increasing the cub mortality rate to 95\% over a period of one to five years, we simulated the effect of otodectic mange epizootic which was observed in the real population of Mednyi Arctic fox. The population recovery time after the end of the impact in the simulation was significantly longer compared to 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. This feedback which accelerates population recovery has not yet been introduced into the model.

Tags

Individual-based model Population dynamics Variability Agent-based modelling Arctic fox Vulpes lagopus