Densities of overwintering carabids and staphylinids (Col, Carabidae and Staphylinidae) in cereal and grass fields and their boundaries

Abundances of carabids and staphylinids were measured during four winters in four fields with grass or autumn ploughed spring cereals, and in their boundaries. Most species were significantly more abundant in the boundaries than in the fields, indicating the high importance of boundaries in the agricultural landscape for these predator groups. Only the carabid Clivina fossor and staphylinids belonging to the genus Lathrobium were evenly distributed throughout the entire area. As none of the species with higher populations in the grass fields and their boundaries were among the important predators of insect pests in agricultural fields, it was concluded that the grass fields were of limited importance as a reservoir for the predatory beetles.