Species-specific limitation of vole population growth by least weasel predation : facilitation of coexistence?

摘要: Interspecific competition is usually understood as different species competing directly with each other for limited resources. However, predators can alter such competitive interactions substantially. Predation promote the coexistence of in a situation where it would otherwise be impossible, example if tradeoff between abilities and predation resistance prey exists. The field vole Microtus agrestis sibling M. rossiaemeridionalis are sympatric grassland species, which compete same At population level voles suggested to superior competitors voles, yet more vulnerable predation. We tested effects on two 0.5 ha outdoor enclosures by exposing populations radio-collared freely-hunting least weasels Mustela nivalis three weeks. Lethal non-lethal impacts densities both during after experimental period, but effect was pronounced decreased markedly treatment period even that. Field remained stable under weasel predation, while increased controls. Survival lower compared controls, tended females species. average mass adults declined populations. These results suggest that limit locally, favourable summer conditions, have extended negative dynamics In addition, alleviated interspecific is, therefore, potential factor enabling them.