Dung Beetle Functional Response and Dung Removal Rates Along an Altitudinal Gradient in Neotropical Rainforests

Dung beetles are a vital component of ecosystems, providing essential ecosystem services. However, the factors that regulate the functional response of dung beetles and dung removal across altitudinal gradients have been scantily explored. Along an altitudinal gradient in rainforests of the Talamanca Cordillera of Costa Rica, we assessed the structure, composition, functional diversity, and dung removal rates of the dung beetle assemblage. We sampled 10 sites between 440 and 3200 m a.s.l. using linear transects with 10 pitfall traps placed 50 m apart for 48 h, and excrement removal experiments. The relationship between altitude and abundance, species richness, and dung removal rates was assessed using quadratic regressions. In addition, beetles were classified into functional groups according to their size and food relocation categories, and six quantitative functional traits were measured. Functional diversity was determined through richness, dispersion, diversity, and functional evenness indices. Beetle abundance, species richness, functional diversity, and dung removal rates were strongly negatively correlated with altitude. Compositional change was also marked along the elevation gradient, with species tending to form two groups, lowland and highland species. There is a solid relationship between dung beetle diversity and ecological processes and altitude, suggesting that factors such as thermal tolerances, dung availability, and abiotic climate variables influence these patterns and that dung beetles are a potential indicator of climate change.