INFLUENCE OF TILLAGE MANAGEMENT AND CROPPING SYSTEM ON GROUND BEETLE (COLEOPTERA, CARABIDAE) FAUNA IN THE NORTHERN GREAT-PLAINS

The ground beetle (Coleoptera: Carabidae) communities associated with cropping systems of spring wheat under various tillage regimes were investigated at two locations in the Northern Great Plains during 1986 and 1987. Forty species of Carabidae were collected. More specimens were collected at Minot, N. Dak., but greater species richness occurred at Williston, N. Dak. Only 14 species accounted for ≥1% of the total number carabids collected. Harpalus pennsylvanicus De Geer was the only species that was shared between locations, accounted for ≥1% of the total number of carabids, and was consistent across cropping and tillage systems. Although Harpalus fallax LeConte was shared between locations and accounted for ≥1% of the total number of carabids, it was not consistent across cropping and tillage systems. The Sorenson similarity index values at Minot were higher especially for the same cropping system. At Williston, the index values were lower, reflecting greater heterogeneity between treatments. Generally, lower numbers of individuals of a given species were found in cropping systems associated with conventional tillage. However, cropping system may have altered communities to higher degree than the tillage regime. © 1990 Entomological Society of America.