Ground beetles (Coleoptera, Carabidae) on set-aside fields in the Campine region and their importance for nature conservation in Flanders (Belgium)

Three set-aside fields of arable land on sandy soil in the Campine region of Flanders (Belgium), differently managed for nature conservation purposes, were sampled for their carabid beetle fauna during a complete year cycle by means of pitfall traps. About 3650 ground beetles belonging to 53 species were obtained. Besides this remarkably high diversity, no less than 11 Red data book species for Flanders were found. These species include three rare, two near-threatened, three vulnerable, two endangered and one critically endangered species. The most notable species were Amara tricuspidata and Harpalus froelichi. Although the results are based on a limited data set, we can conclude that, at least for ground beetles, conversion of agricultural fields to set-aside poor fields or dry grasslands has great potential with respect to regional conservation biology in the Campine region. Ordination of the data shows that each field can be characterized by a somewhat different carabid beetle community. The restricted data do not allow us to conclude which management measures seem most appropriate. The safest recommendation at this stage is to use a variety of practices on different fields, in order to enhance general diversity, and, above all, to avoid afforestation. Traditionally managed arable land thus can have a distinctive and comparatively species-rich carabid fauna, which recently has become endangered to a high degree.