Habitats and Management Associated with Common Ground Beetles (Coleoptera: Carabidae) in a Michigan Agricultural Landscape

The associations between common ground beetles and habitat and management characteristics were studied in an agricultural landscape that comprised part of the Long-Term Ecological Research site in southwestern Michigan. The 42-ha area included 7 habitat treatments, which represented 4 annual cropping systems in wheat, Triticum aestivum L., corn, Zea mays L., soybean, Glycine max (L.) Merr., rotation; 2 perennial crop systems (alfalfa, Medicago sativa L., and Populus ); and a native succession habitat. Pitfall traps were used to sample adult ground beetles during the growing seasons of 1994 and 1995. Four species numerically dominated the trap catches and together accounted for 87% of the total specimens collected: Cyclotrachelus sodalis (LeConte), Poecilus lucublandus (Say), Pterostichus melanarius (Illiger), and Agonum placidum (Say). Differences in representation of these common species were most pronounced between perennial and annual plant systems. However, tillage also influenced the relative abundance of these species. The adult-overwintering, spring-breeding species, P. lucublandus and A. placidum , were most common in the annual crop habitats, particularly those under conventional tillage. Catch numbers of these 2 species were correlated positively, suggesting similar habitat preferences or responses to management practices. In contrast, C. sodalis , a larval-overwintering, autumn breeder, was most common in the perennial crop systems and the annual crop system receiving no tillage. The exotic species P. melanarius showed the least response to the agricultural habitat treatments but was more abundant in managed crop habitats compared with the unmanaged succession habitat. Cluster analysis based on these 4 species indicated that plant type and tillage were important in distiniquishing the carabids of these habitats. The potential implications of these findings for conserving or enhancing ground beetle populations in agricultural systems are discussed.