WEEDS DETERMINE THE COMPOSITION OF CARABID ASSEMBLAGE IN MAIZE AT A FINE SCALE

Weeds cause problems to farmers but on the other hand they contribute to the local biodiversity by providing food and shelter for many insect species and birds, many of which are dependent solely on weeds. In this paper we investigated how composition of weed assemblage in a small maize field (400 m2) affects composition of assemblages of carabid beetles at the scale of metres. By using pitfall traps and sampling weeds around them, we were able to show that carabid beetles respond to composition of weed assemblage at this fine scale. Percentage cover of bare ground, Viola arvensis, Lolium multiflorum, Persicaria maculosa, and Echinochloa crus-galli significantly affected composition of carabid assemblages in the study field. Twentynine significant correlations were found between carabid activity density and percentage cover at the species level. We therefore conclude that a diverse weed community promotes carabid diversity in arable fields. This, besides being a value itself from the perspective of biodiversity conservation, fosters the ecosystem services including pest and seed predation by carabid beetles.