Influence of environmental heterogeneity on the structure of the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) assemblage of the Cerrado savanna of northeastern Brazil

Although scarabeine beetles have considerable ecological importance in the functioning of tropical ecosystems, and their species diversity varies with changes in land use, this process is poorly understood in the Brazilian Cerrado. We compared the diversity (patterns of species richness, composition, and abundance) of scarabeine beetles among gallery forest, terra firme forest, and pasture environments. We also analyzed which scarabeine beetle species are associated with different environments of the watershed of the Lajeado river, in the state of Maranhao, northeastern Brazil. The scarabeine beetles were collected using pitfall traps in 30 localities, including 10 localities selected from each of the three environments, located in five municipalities. A total of 2,855 beetles were collected, representing 17 genera, and 62 species. The highest species richness and abundance were recorded in the terra firme forest, followed by the pasture, and then the gallery forest, which had the smallest number of species, but abundance comparable to that of the pasture. The species composition was different between the forest environments and the pasture. The species Canthon aff. xanthopus (Blanchard, 1846) and Deltochilum enceladus (Kolbe, 1893) were associated with terra firme forest, while Canthidium aff. barbacenicum (Preudhomme de Borre, 1886), Canthon octodentatus (Schmidt, 1920), Coprophanaeus magnoi (Arnaud, 2002), Dichotomius bos (Blanchard, 1846), Dichotomius nisus (Olivier, 1789), and Pseudocanthon xanthurus (Blanchard, 1846), had a strong relationship with the pasture. Eurysternus caribaeus (Herbst, 1789) was associated with terra firme forest and gallery forest environments. Therefore, the distribution and association patterns of the dung beetle species varied considerably among the different environments.Implications for insect conservation Overall, the results of the present study emphasize the importance of preserving the heterogeneity of Cerrado habitats, which may provide resources that support the preservation of insect communities and the ecosystem services they provide, given that different dung beetle species tend to prefer specific types of habitat. In addition, due to the proximity of the study area to a transition zone (the Cerrado-Amazonian ecotone), some species found in the present study have also been recorded in Amazonian environments. This reinforces the importance of conserving transition environments for the maintenance of local biodiversity.