Dung beetles as bioindicators of environmental change from artisanal small-scale gold mining

The expansion of gold mining across Amazonia is a major driver of deforestation, yet its impacts on biodiversity are understudied. Dung beetles (Scarabaeinae) are excellent bioindicators and have been shown to be highly sensitive to habitat modification, especially within the tropics. Furthermore, they provide key ecosystem services. We quantify the impact of gold mining on dung beetle assemblages in 16 abandoned gold mines of different sizes and years since abandonment, in northwest Guyana. We surveyed dung beetles using baited pitfall traps at the centre of the mines, at the edges and 100 m into adjacent forest. We show that gold mining significantly reduces dung beetle species richness and abundance, with the most pronounced declines occurring in areas with a higher intensity of mining within a 500 m radius. We measured environmental covariates and found that while mine area had no notable effect on species richness, elevated temperatures and reduced canopy cover in the mine centers had negative consequences for dung beetle assemblages. Conversely, increasing canopy cover was positively associated with dung beetle richness and abundance. However, overall, we find no significant recovery of dung beetle communities up to two decades following mine abandonment. Our findings suggest that the expanding artisanal and small-scale gold mining in Amazonia could have lasting detrimental effects on dung beetle assemblages and the important ecosystem services they provide.