The effects of harvest on arable wood mice Apodemus sylvaticus

The effects of cereal harvesting on the ecology of wood mice Apodemus sylvaticus were investigated at three arable study sites in Oxfordshire from 1987 to 1991 using both radio-tracking and live-trapping methodologies. The process of harvesting itself had little direct effect on the mice, but the removal of the cover afforded by the crop greatly increased predation pressure on the mice. After harvest, mice either emigrated from the arable ecosystem or reduced activity. Nevertheless, over half (17 of 32) of the mice radio-collared before harvest were taken by predators in the first week following harvest. Together with emigration, this produced an 80% decrease in the population. Post-harvest activities such as stubble burning subsequently further increased mortality. The dramatic increase in prey availability may benefit predators of small mammals in the cereal ecosystem such as tawny owls Strix aluco and weasels Mustela nivalis. © 1993.