The role of man-made grassy habitats in enhancing carabid populations in arable land.

Abstract

1. Grass-sown habitats were created in the centres of two cereal fields as a management strategy to diversify the agroecosystem and to provide improved overwintering conditions for predatory Carabidae.
2. Surface counts in the new habitats revealed overwintering carabid densities up to 60 m^-2 during the first year of establishment.
3. Absolute sampling of the within-field habitats during the second winter (1988/89) revealed carabid densities approaching 1000 m^-2.
4. The extent of spring emigration of carabids from the new habitats was monitored using artificial prey.