Analyzing effects of ivermectin on cattle dung arthropod communities

Dung pats left behind by grazing cattle in pasture ecosystems provide a nutrient rich resource of digested plant material.  A diverse group of insects use the cattle dung, contributing to the health of pastureland. This group of insects recycles animal dung into the soil and reduces pathogens and parasites associated with dung. The ecological services that these insects provide are well documented, but the potentially harmful effects current herd management practices, such as ivermectin parasiticides, on beneficial species have received little recent attention. This project examined potential non-target effects of these practices to dung arthropods on 10 different ranching operations across nine counties of Eastern South Dakota. Each ranch was sampled to test if there is a connection between the use of ivermectin and the abundance and diversity of dung arthropod communities, both beneficial and pest. Tens of thousands of dung arthropods were collected throughout the season, providing a snapshot of how arthropod communities changed. This research gives a better understanding of how herd management decisions can affect non-target organisms.