Ground beetle (Coleoptera: Carabidae) activity in Colorado dryland cropping systems

We determined active ground beetle species in 2002 and 2003 in experimental dryland cropping systems near Akron, Briggsdale, and Lamar, CO. The experiment compared five crops: wheat, sunflower, sorghum, millet, and corn in fallow, two- and three-year cropping systems. Comparisons were made between all crops and fallow within locations. Pitfall traps were used to collect active ground beetles in plots for seven, seven-day sampling periods in both 2002 and 2003. A total of 3,929 carabids was collected; 1,684 and 2,245 in 2002 and 2003, respectively. A total of 59 species was collected, 51 and 49 in 2002 and 2003, respectively. In 2002, the five most active species (in decreasing order) were Pasimachus californicus Chaudoir, Amara carinatus LeConte, Harpalus pensylvanicus DeGeer, Harpalus desertus LeConte, and Pasimachus elongates LeConte. The five most active species (in decreasing order) in 2003 were H. pensylvanicus, Harpalus caliginosus Fabricius, H. desertus, Cratacanthus dubius Beavois, and Harpalus amputates Say. Seven species were common to Akron, Briggsdale, and Lamar in both 2002 and 2003. Ten and eight species were specific to 2002 and 2003, respectively. Eight, fourteen, and four species were specific to Akron, Briggsdale, and Lamar, respectively. Crops and dates influenced ground beetle activity, but two- and three-year cropping systems did not.