Understorey bird responses to the abandonment of artisanal gold mining in Guyana

Artisanal small-scale gold mining (ASGM) is linked to deforestation across Amazonia. In the Guiana Shield region, ASGM is responsible for around 90% of deforestation and forest degradation, making it the largest threat to species richness in this biodiverse region.

In Guyana, ASGM sites typically remain surrounded by intact forest, creating an ‘enclosed edge’ ecosystem. We currently have a poor understanding of the biodiversity value of these areas, or the capacity for ecological recovery once mining activity has ceased.

We surveyed 16 ASGMs of differing mine sizes and years since abandonment, sampling bird community and vegetation structure in the centre of each mine, the immediate mine edge, 100 m from the mine edge and in five control forest sites.

Mines and their immediate edges supported unique bird assemblages, with few forest-dependent species and many generalists. However, species composition in the forest 100 m from mine edges remained similar to control forest, implying that any edge effects radiating from mines were minimal. Forest-dependent species numbers were positively related to time since mine abandonment, yet full recovery of the bird community was not observed, even in mines that ceased activity 20 years previously.

We found a positive relationship between the number of forest-dependent bird species and canopy cover, suggesting that as vegetation regrows and canopy cover increases, the forest avifauna is able to recover.

Policy implications. Whilst many forest-dependent birds will avoid the exposed mine centre, diversity at the immediate edge has the potential to recover, particularly in smaller and older mines. As we have found that natural vegetation recovery occurs at the mine edges and not within the centre, targeted restoration efforts might focus on mine edges to enhance recovery rates, whilst ensuring that populations in nearby forest remain viable sources to repopulate these degraded habitats.