effect of winter food stores on body mass and winter survival of water voles, Arvicola terrestris, in Western Siberia
Title:
effect of winter food stores on body mass and winter survival of water voles, Arvicola terrestris, in Western Siberia the implications for population dynamics
The study was performed to test the hypothesis that winter food deficit can act to reduce a water vole, Arvicola terrestris, population in Western Siberia. During 12 years, a total of 139 wintering burrows were examined at different phases of population cycles. The size of food stores was found to be greater during increases of the population compared to that at the peak and the decline. Comparison of the mass of stores in burrows and the daily consumption of natural foods under controlled conditions shows that only a small fraction of individuals have sufficient food supply for safe wintering. Females have smaller stores compared to males, and this is possibly responsible for their higher winter mortality. The size of food stores in October affects both winter change in body mass as defined by difference between average mass in samples of animals captured in October and in May of the next year and winter survival determined as a ratio between population densities in May and October. The deficiency of food during winter is likely to be a strong factor affecting body mass change, density, sexual and age structures, and reproductive potential in the water vole population in Western Siberia.