EFFECTS OF HEADLAND MANAGEMENT ON INVERTEBRATE COMMUNITIES IN CEREAL FIELDS

Two of the management prescriptions for the Breckland Environmentally Sensitive Area in East Anglia, Great Britain, concern the outer 6 m of cropped fields: 'Uncropped Wildlife Strips' (no crop sown and restricted pesticide applications) and 'Conservation Headlands' (restricted pesticide applications). The impact of these two management regimes on communities of spiders, carabid beetles and Heteroptera in cereal field headlands was evaluated in 1988. The total abundance of each group was highest in uncropped strips, but also higher in Conservation Headlands than in fully sprayed headlands. Species diversity for spiders and Heteroptera was significantly higher in uncropped strips and Conservation Headlands than in fully sprayed headlands. Species richness for both these groups and carabids was higher in all fields in uncropped headlands and Conservation Headlands than in the fully sprayed controls. The community structure of carabids and spiders was altered by headland management; it also changed with the age of the uncropped strips. Movement of Heteroptera from field boundaries into the crop was affected by headland treatment. The implications of these results are discussed with reference to gamebird survival, biological control of cereal pests and wildlife conservation issues.