Diet Quality Limits Summer Growth of Field Vole Populations

摘要: Marked variation occurs in both seasonal and multiannual population density peaks of northern European small mammal species, including voles. The availability dietary proteins is a key factor limiting the growth herbivore species. objective this study to investigate degree which protein influences increasing vole populations. We hypothesise that summer folivorous populations positively associated with availability. A field experiment was conducted over reproductive period 18 vegetated enclosures. Populations voles (Microtus agrestis) were randomised amongst three treatment groups: 1) food supplementation ad libitum high (30% dry weight) pellets, 2) low (1% weight; supplemented foods had equivalent energy content) 3) control (no supplementation), n = 6 per treatment. Vole density, survival, demographic attributes condition indicators monitored live-trapping blood sampling. Highest final densities attained received lowest Control displayed intermediate densities. survival rate similar all groups. proportion females, those pregnant or lactating, highest This suggests reproductive, rather than rates voles, accounted for differences between found no clear association demography individual physiological condition. Our results demonstrate limits during growing season. nutritional quality forage may be an underestimated source interannual widely fluctuating herbivorous mammals.