Functional reorganization of dung beetle assemblages in forest-replacing sugarcane plantations

Abstract: Tropical forests worldwide have succumbed to rapid conversion into agricultural landscapes, but the local- and landscape-scale drivers of functional diversity and consequently ecosystem functioning remain poorly known, which limits management and conservation strategies. Here, we quantitatively assess how biofuel croplands affect taxonomic and functional diversity as well as trait-composition of dung beetle assemblages in a hyper-fragmented landscape of the Brazilian Atlantic forest dominated by sugarcane plantations. We also examine to what extent changes in patch attributes (patch scale forest loss), landscape composition (landscape scale forest loss) and landscape configuration (degree of fragmentation and forest edge density), induced by the establishment of sugarcane plantations, affect the functional reorganization of dung beetle assemblages. We estimated taxonomic and functional diversity (functional richness, evenness and redundancy) of dung beetle assemblages at 50 sampling sites across a sugarcane dominated hyper-fragmented landscape. In general, sugarcane plantations showed lower functional diversity than forest sites. Large-bodied coprophagous tunnelers were dominant across all forest sites, while small-bodied generalist-rollers were more abundant in sugarcane plantations. Functional evenness and dispersion were negatively affected by landscape composition, while landscape configuration and forest loss played a minor role. Our findings indicate that changes at both the patch and landscape scales induced by the establishment of sugarcane plantations exert strong impacts on the taxonomic and functional diversity of dung beetles. Implications for insect conservation: These shifts in functional diversity can disrupt ecological functions served by these insects which, in turn, can accelerate the collapse of ecosystem functioning across tropical landscapes immersed in sugarcane plantations.