Dam failure disrupts Atlantic Rainforest ant communities and their interactions with seeds.

In November 2015 occurred the largest environmental disaster in the world mining industry – the collapse of the Fundão tailings dam in Mariana, Minas Gerais state, Brazil. The dam's tailings buried and contaminated large areas of the Doce River catchment, its estuary, and the surrounding Atlantic Rainforest. Despite the severity and extent of this disturbance, our knowledge about tailings dam failure impacts in terrestrial invertebrate biodiversity and their ecosystem functions remain limited. We investigated the impacts of the dam failure on surrounding Atlantic Rainforest ant communities and their interactions with seeds, two years and four months after the failure. Ant composition changed, as some species were lost and replaced by others. While species richness and number of individuals remained unaffected, 26 species were lost from the affected communities, leading to the phylogenetic impoverishment of the community. The tailings also altered ant-seed interactions, increasing the time ants took to locate a seed and the distance of seed removal. As ants are well-established bioindicators, these impacts likely extend to other faunal groups. The cascading effects of such impacts on forest regeneration are still unclear, as are the potential effects of the observed changes in ant communities on other ecosystem functions ants perform. Implications for insect conservation: Our study shows how a large-scale human-induced impact can affect ant communities and their key role in seed dispersal. Understanding how severe and extensive disturbances affect biological communities is key for devising remediation and recovery strategies in disturbed areas. This knowledge aids in restoring the native flora and fauna in these ecosystems. [ABSTRACT FROM AUTHOR]