Assemblage structure and ecological functions of dung beetles in exotic pastures in the Southwestern Amazon

Abstract The implementation of exotic pastures in the Amazon causes drastic negative impacts on its biodiversity. Nevertheless, some species with the ability to colonize pastures may provide important ecosystem services for livestock development in tropical pastures, as in the Amazonian biome. In this study, we evaluated the diversity and assemblage structure of dung beetles, as well as measured their ecological functions (i.e., dung removal and soil excavation) in exotic pastures in the Southwestern Amazon. Dung beetles were sampled using pitfall traps baited with fresh cattle dung, and their ecological functions were measured using experimental arenas during the rainy season. A total of 123 individuals were collected, belonging to five genera and nine species of dung beetles. Dung beetle assemblage had more species of small to medium body size (< 8 mm), with only two species classified as large-bodied. Large and small telecoprids were the most abundant functional groups. The mean (± SE) values for dung removal and soil excavation were 10.9 ± 2.33 g and 15.2 ± 4.22 g, respectively. These findings indicate that only a limited number of dung beetle species are able to colonize exotic pastures in the Southwestern Amazon, predominantly those of small to medium body size, which leads to a reduction of key ecological functions in these environments.