Differential responses of grassland ground beetle (Coleoptera: Carabidae) communities to Conservation Reserve Program management practices
Grasslands of the Great Plains have declined over 70% since European settlement due to conversion of natural habitats to cropland and urban centers. The federally supported Conservation Reserve Program (CRP) was created to improve water quality, reduce soil erosion, and increase native habitats for wildlife. Within these restored grassland ecosystems, ground beetles (Coleoptera: Carabidae) are a keystone invertebrate group that fill several crucial niches and may serve as bioindicators of successful land management strategies. Using pitfall traps at 108 CRP sites across 650 km and a precipitation gradient of 63.5 cm, we examined the response of carabid beetle richness and abundance to a low diversity (CP2) and relatively high diversity (CP25) initial seeding and a grazing treatment (grazed or ungrazed) over two field seasons. We captured 4,841 carabid beetles representing 48 species across this wide gradient. Overall, grazing and CP treatments did not have a detectable effect on carabid abundance, biomass, or diversity. However, we found significant, positive effects of grazing on all three metrics in tallgrass habitats (strongly correlated with precipitation and plant community diversity). There were no effects of CP on the ground beetle community. Additionally, we found that species turnover was correlated with habitat transitions found along the precipitation gradient. Our findings suggest that moderate grazing by cattle over two seasons does not negatively affect carabid communities and that carabid communities respond differently to the effects of land management across a precipitation gradient and grassland habitats.
Thesis (M.S.)-- Wichita State University, College of Liberal Arts and Sciences, Dept. of Biological Sciences
This thesis is embargoed till the end of August 2020.