Regional environmental filters modulate the bee community in a landscape impacted by Brazil's largest mining disaster

The collapse of the Fundão dam in 2015 was Brazil's most serious environmental disaster, but our understanding of its long-term effects on pollinator communities is limited by the absence of pre-disaster surveys. This reflects a gap in research on pollinators in mining affected landscapes. The Fundão dam belonged to mining company Samarco, and this study evaluated the effects of mining tailings on bee communities along the Rio Doce watershed, comparing impacted sites (IS) and reference sites (RS; non-impacted) in five regions. The bee survey yielded 10,721 individuals from 88 species during dry and rainy seasons. Contrary to the hypothesis of a drastic decline, species richness did not differ between sites (IS = 13.53; RS = 12.40). Bee abundance was higher in impacted than reference sites (197.33 vs. 160.06), driven mainly by collections in the dry season. Statistical modelling showed that abundance was positively associated with native forest cover and clay soils, but negatively associated with distance from tailings and organic matter. Bee community composition was strongly shaped by environmental filters (R2 = 0.60), while tailings explained minimal variation (R2 = 0.03). Beta diversity was predominantly driven by species replacement (turnover) rather than species loss (nestedness). Our results demonstrate that, at this scale, the mining tailings disaster did not negatively affect bee richness and composition. Instead, the bee community exhibited resilience, likely supported by native forest remnants that function as source habitats, facilitating colonization and recolonization of impacted areas by providing essential floral and nesting resources. Conservation efforts should prioritize preserving native forest remnants and restoring soil physical properties in impacted sites to sustain pollinator diversity in landscapes under mining stress.