Predicting spatial and temporal habitat use of rodents in a highly intensive agricultural area

Abstract

Landscape modifications in combination with a highly intensive agriculture are known to have negative impacts on farmland biodiversity. Small rodents play a crucial role in agricultural ecosystems because they provide important ecosystem functions. They are important links in food webs, but also pest species to various kinds of crops. Here, we want to find trade-offs between small rodent conservation and rodent pest control in agriculture. We predicted abundance, species richness and community composition of small rodents in relation to landscape scale effects (measured as % of arable land along a gradient of landscape complexity), local scale effects (agricultural fields vs. semi-natural vs. natural habitats, as well as vegetation cover) and temporal variations within a growing season (before and after the crop harvest) simultaneously. Results show that increasing vegetation cover increased rodent abundance and species richness and influenced community composition after the crop harvest. Local scale effects influenced rodent abundance with lowest abundance in grasslands compared to semi-natural and natural habitats, whereas landscape scale effects influenced species richness which increased with increasing % of arable land. Apodemus agrarius (striped field mouse) was most abundant in field margins and increased with increasing vegetation cover after the crop harvest. Myodes glareolus (bank vole) was most abundant in kettle holes, but as isolation of these habitats increased, abundance decreased. A compromise between nature conservation and crop protection would be an agricultural landscape with crop field interspersed by natural and semi-natural habitats, which are arranged within rodent dispersal distances, providing a high vegetation cover. Grasslands can act as sink habitats and may reduce rodent spillover into agricultural fields facilitating pest control. Special attention has to be paid to the protection of natural habitats such as kettle holes, because they can act as source habitat facilitating rodent conservation.