Status of the non-native short-tailed field Vole (Microtus agrestis) (Rodentia, Cricetidae) in Ireland

We report the distribution of the Short-tailed Field Vole (Microtus agrestis) a recent arrival to Ireland, and discuss its probable deliberate introduction at multiple sites in the northern third of the island. It is a potential competitor of other small mammal species, both native and alien, and prey for a range of specialist and generalist avian and mammalian predators. It is not clear whether M. agrestis will simply replace existing prey items rather than become additional food for Irish raptors and carnivores. M. agrestis may also act as a reservoir for existing and novel pathogens of animals and humans. A first Draft Rapid Risk Assessment indicates that the introduction of M. agrestis represents a significant but not immediately severe threat to ecological sustainability and human health in Ireland. Deliberate introduction of non-native species and moving them within
Ireland is illegal in northern and southern jurisdictions and further degrades Ireland’s biodiversity which is becoming less unique with each new arrival.