Coal mining is a major driver of land-use change in the US. According to the Energy Information Administration, coal is expected to remain a key part of the national electricity portfolio until at least 2040. It is therefore crucial to understand the environmental impact of coal mining. Whereas a scientific consensus has emerged that coal mining negatively affects water quality, a quantitative synthesis of biodiversity impacts is currently lacking. Here, we used hierarchical meta-analytic models to elucidate the impact of coal mining on stream biotic richness and abundance of different taxonomic groups across different mining systems under existing statutes [the 1972 Clean Water Act (CWA) and the 1977 Surface Mining Control and Reclamation Act (SMCRA)]. We combine data on fish species ranges and county-level coal production to identify watersheds of conservation concern where current/near-future coal production as well as endemic/threatened fish species richness are highest.
Results/Conclusions:
Our analysis indicates that mining under existing regulations do not fully protect freshwater biota. Streams affected by coal mining averaged 32% (95% CI: 24–40%) lower taxonomic richness and 53% (10–75%) lower total abundance than unmined streams, with these impacts occurring across all taxa investigated thus far (invertebrates, fish, and salamanders). A central aim of SMCRA is to ensure mining companies complete reclamation (i.e., rehabilitation of mined areas to pre-mined condition) by requiring them to post a performance bond. However, even when reclamation is completed, mined sites supported on average only 66% (95% CI: 54–80%) of the richness and 32% (10–101%) of the abundance in unmined sites (Fig. 2). Watersheds of conservation concern based on endemic richness are concentrated in the central and southern Appalachians whereas those based on threatened richness are concentrated in the same two aforementioned regions as well as in the Colorado Plateau. Improvements in regulations and their enforcement are needed to reduce the impact of coal mining on stream biodiversity.