Survey of Diversity and Abundance of Ground-dwelling Arthropods in a Black Walnut-forage Alley-cropped System in the Mid-western United States

Alley cropping is an integrated land management practice growing economic crops between rows of trees. This paper examines the effects of alley cropping on carabid beetles and other ground dwelling arthropod predators on species diversity and abundance by testing for differences among ground vegetation treatments in alleyways. Arthropods were collected with pitfall traps in two alley-cropped areas using the ground cover treatments of alfalfa, smooth bromegrass, and a vegetation-free control. Although not generally statistically significant, brome had the lowest means of any of the ground vegetation treatments, possibly due to the relative impenetrability of the thick grass. We found few significant differences among treatments. Carabidae numbers were negatively correlated with relative humidity and positively correlated to soil temperature and moisture. Sampling methods other than pitfall trapping are needed in future studies to clarify the role of ground cover in arthropod predator diversity and abundance in an alley cropping practice.