Influence of cattle grazing practices on dung beetle (Coleoptera: Scarabaeoidea) communities in the Sandhill rangelands of Central Nebraska

Dung beetles (Coleoptera: Scarabaeoidea) have a significant role in regulating the ecosystem services they provide on rangelands. Colonization of dung piles by dung beetles can help facilitate the decomposition of dung, control dung-breeding pests, and cycle important nutrients into the soil to improve pasture quality. Cattle are grazed on pastures at various stocking densities depending on the type of grazing practice. The influence of grazing practices on dung beetle communities and services remains largely unknown. Our first study investigated dung beetle activity across different cattle grazing practices to determine how grazing might influence dung beetle abundance and diversity. Dung beetle populations were monitored throughout the grazing season on pastures that were grazed under various practices: non-grazed/hay, continuous grazing, low-stocking rotational grazing, and high-stocking (mob) rotational grazing. Results from this study showed significantly higher dung beetle diversity on pastures exposed to rotational grazing practices compared to continuous grazing or no grazing. In some cases, dung beetle abundance and species richness were significantly greater on pastures that were grazed through high-stocking rotational grazing compared to low-stocking rotational or continuous grazing treatments. Based on these data, rotational cattle grazing may favor the colonization of dung beetles on rangeland, regardless of stocking density. Our second study investigated whether dung beetles exhibit preferences for dung from cattle exposed to different grazing practices. Dung from cattle in three separate grazing practices were used to test dung beetle preference: continuous grazing, low-stocking rotational grazing, and high-stocking rotational grazing. Dung beetle abundance was measured as well as the nutrient and physical properties of each dung type. Results of the study revealed no significant differences in dung beetle abundance between dung collected from each grazing practice. Nutritional content, pH, moisture, and dry matter levels also were not significantly different. However, the results indicated varying dung beetle species composition on dung from the continuous versus rotational grazing practices. Overall, cattle grazing practices may not affect dung composition or its influence on dung beetle preferences. Advisors: Jeffrey Bradshaw and Thomas Weisslin