The role of livestock intensification and landscape structure in maintaining tropical biodiversity.
Abstract
As tropical cattle ranching continues to expand, successful conservation will require an improved understanding of the relative impacts of different livestock systems and landscape structure on biodiversity. Here, we provide the first empirical and multi-scale assessment of the relative effects of livestock intensification and landscape structure on biodiversity in the threatened tropical dry forests of Mesoamerica. We used a dataset of dung beetles (169,372 individuals from 33 species) collected from 20 1-km2 landscapes, ranging from zero-yielding forest sites to high-yield cattle ranches and maize farms, to investigate the relative effect of livestock intensification (net cattle production; macrocyclic lactone use; annual dung production) and landscape structure (landscape composition and configuration) at multiple spatial scales on different attributes of dung beetle communities using a multi-model averaging approach. Dung beetle species richness, biomass and composition were more strongly related to landscape structure than to livestock intensification. Forest cover was the best predictor of dung beetle assemblages, being positively related to species diversity and biomass across multiple spatial scales. The use of macrocyclic lactones was strong and negatively related to dung beetle communities at the local scale. Synthesis and applications: Maximising forest protection through a "land sparing" strategy is likely to be the best strategy for reducing negative impacts of cattle farming on Neotropical dung beetle communities. However, increasing or maintaining yields while reducing agrochemical inputs will be important for conserving on-farm biodiversity and the ecosystem services that dung beetles provide in livestock-dominated landscapes.