This dataset contains species richness, Sorensen dissimilarity and its components of species turnover (total and proportional) and nestedness-resultant (total and proportional) data for five groups of insects (ants, bees, butterflies, dung beetles, and termites) sampled in 20 sites across three habitat categories: legally protected areas (PRO), reference sites (REF), and forest fragments adjacent to the mudflow (MUD), conducted in the municipality of Brumadinho, Minas Gerais State, southeastern Brazil. The region gained international attention following the collapse of a tailings dam on 25 January 2019, owned by the Brazilian mining company Vale S.A. The original vegetation of the region was predominantly Atlantic Forest, mainly composed of semideciduous forests, with patches of savanna and rocky-shrubby vegetation at higher altitudes, owing to its location near the transition zone between the Atlantic Forest and Cerrado biomes. Eight sites were in legally protected areas (PRO), with which we aimed at understanding the best possible background scenario in the region: three in Special Protection Area of Rio Manso (which sources water to Belo Horizonte Metropolitan region), three in Inhotim Private Reserve, and two in Rola Moça State Park. Six additional sites were classified as reference areas (REF), consisting of secondary forest patches within the landscape unaffected by the tailings but potentially subject to other disturbances.

Aim: Ancient tropical mountains are megadiverse, yet little is known about the distribution of their species. We aimed to disentangle the effects of latitudinal and elevational gradients on the distribution of species of Aculeata and to understand the effects of climatic variables across different spatial scales of diversity (α, γ, and β-diversity). Location: Campo rupestre in the Espinhaço Mountain Range, Southeast Brazil. Taxon: Bees, wasps, and ants (Aculeata: Hymenoptera) Methods: We used a unique dataset built from sampling species of Aculeata at 24 study sites across 12 mountains, covering 1200 km from south to north and an elevational range of 1000 to 2000 m. We explored the elevational and latitudinal patterns of α (site), γ (mountain), and β-diversity among samples at each location (β Local). We also tested the effect of elevational range on β-diversity in each mountain (β Mountain) and, on a larger scale (β Regional), if β-diversity is influenced by geographical and environmental distances. Finally, we tested whether climatic variables underpin the observed patterns. Results: Latitude had no effect on diversity. We found a decrease in both site and mountain diversity and, only for bees, β Local increased with elevation. Climatic variables (temperature, wind, and precipitation) and their interactions were important drivers of diversity, with temperature being the most important. Finally, β Mountain increased with mountain elevation range, and β Regional increased with the geographical and environmental distances. Main conclusions: Our results showed that variation in species richness and composition across mountains is strongly associated with elevational gradient, which showed stronger climatic variation than latitudinal gradient. Therefore, despite having narrow elevational ranges, the biogeographical effects of tropical mountains drive high diversity. Facing global climate changes, this limited elevational gradient may limit species range shifts, leading to severe biodiversity losses.