The effect of artisanal gold mining on aquatic insect communities: a case study in Costa Rica

Abstract

Among the anthropogenic disturbances that affect rivers, artisanal and small-scale gold mining (ASGM) has recently generated great concern regarding the deterioration of aquatic ecosystems. This study aimed to evaluate the impact of ASGM on the assemblages of aquatic insects. For this, aquatic insects were sampled from two actively mined streams in the Osa Peninsula in Costa Rica. ASGM produces significant changes in the richness, abundance and assemblage’s composition of aquatic insects. These changes, however, are mitigated a few meters downstream, after encountering a seemingly undisturbed tributary, for which the stream seems to keep its stability through resilience. For ASGM activities that have low intensities of extraction and don’t use pollutant chemicals for amalgamation, keeping a low intensity of the activity and a considerable distance between goldmining sites could be an option for a more sustainable development of this activity, since it allows biodiversity to be partially restored.