Ivermectin impacts on dung beetle diversity and their ecological functions in two distinct Brazilian ecosystems

Abstract

Abstract The indiscriminate use of Ivermectin is becoming a frequent scenario in Brazil, one of the largest beef cattle herds in the world, and the second‐highest commercial production, despite this product having harmful effects on non‐target organisms. Among these organisms, dung beetles are essential for the maintenance of ecosystem functioning in introduced pastures. This study evaluated the effects of Ivermectin on dung beetle assemblage attributes (species richness, abundance, species composition, functional groups and indicator species) as well as their ecological functions (dung removal and soil bioturbation) in introduced pastures with different priorities for livestock intensification in Brazil; Amazon (high) and Pantanal (low). We found a negative response of dung beetle assemblages to Ivermectin in both Brazilian ecosystems, where these negative effects were more pronounced in the Pantanal. Tunneler beetles are the functional group most negatively affected in both ecosystems. Finally, the Ivermectin reduces the ecological functions performed by dung beetles, with a dung removal reduction of ca. 50% and 70% in the Amazon and Pantanal, respectively. The most negative impacts in the Brazilian Pantanal reflect the long‐term consequences due to a long history of Ivermectin use than in the Amazon. However, these results also indicate a drastic future for dung beetles in Amazonian pastures. Thus, a sustainable cattle production system reducing Ivermectin use will be important for conserving dung beetles on introduced Brazilian pastures and the ecological functions that these insects provide in livestock‐dominated landscapes.