Dung beetle communities of altitudinal Atlantic forest remnants: diversity and composition

The Altitudinal Atlantic Forest is comprised of humid forest enclaves on top of the mountains surrounded by the Caatinga's xeric shrubland vegetation. It is considered a humidity refuge of endemism in semi-arid regions, and it is under intense anthropogenic pressure. Dung beetle communities are widely used as an ecological indicator of environmental conservation. However, dung beetle communities of the Altitudinal Atlantic Forest are poorly studied, and their value for biodiversity conservation in semi-arid regions is unknown. We describe and compare dung beetle communities of Altitudinal Atlantic Forest remnants located in the Brazilian Northeast semi-arid region to evaluate whether diversity patterns and species composition differ among the remnants. We captured 1,333 beetles belonging to 24 species. Only one remnant showed a statistically significant difference in diversity based on species richness and abundance, and beta diversity showed a high dissimilarity among remnants. The remnants had in common only one species, and the dominant species were distinct among them. Species composition was 16% similar among the sampled remnants, and we registered species commonly found in the Atlantic Forest, the Caatinga, and Amazonia. The structure of the dung beetle community in each remnant could be related to the historical origin and maintenance of the Altitudinal Atlantic Forest. Species compositions changed as a result of geographic location and surrounding environments, which act as filters to dung beetle species flow and establishment. We highlight the importance of the Altitudinal Atlantic Forest for the conservation and maintenance of biodiversity in the semi-arid region.