The distribution and movement of ground beetles in relation to set-aside arable land

Abstract

The distribution and movements of Carabus nemoralis were studied in set-aside, semi-natural and arable habitats on a farm in NE Scotland to help interpret pitfall trap catches and determine habitat preferences. Mark-recapture was employed to determine population estimates and dispersal patterns, while a radar tracing technique was used for detailed studies of the movements of male beetles. Both techniques demonstrated a high level of between-habitat dispersal by male C. nemoralis. Little activity was observed on nights with soil surface temperatures below 4°C but on warm nights beetles would travel at about 42 m/hr in arable areas, 6 m/hr in set-aside and 2 m/hr in semi-natural habitats. An index of habitat preference was derived based on pitfall trap catches and activity levels in different habitats. Based on this index, C. nemoralis seemed to prefer semi-natural habitats to set-aside to arable areas. Set-aside land may not form extensions of adjacent semi-natural habitats but may nevertheless contribute to increasing conservation potential on farmland.