Which carabid species (Coleoptera: Carabidae) profit from organic farming after a succession of 15 years?

Abstract

The changes of the ground beetle assemblages during the 15 years succession after the conversion from conventional to organic farming was investigated in northern Germany, with the aim to find trends for the communities on organically farmed fields. The succession showed that the carabid assemblages developed from typically wide-spread communities on loamy soils to assemblages, which are typical for more sandy soils and open habitats. All nine fields studied had the same direction in their succession. At the beginning, the composition of the assemblages was nearly similar but they developed during the succession into more diverse communities with a greater heterogeneity and changes between years. A detailed analysis of ecological groups revealed that species preferring forest margins disappeared from the fields, whereas species preferring open habitats benefited from the conversion. Some species were able to disperse further into the field centres, some could invade from the field margin to the centres and some newly immigrated during the succession and could also disperse into the field. The conclusion drawn from these results is that, in general, species from open habitats will benefit from organic fields.