Amphibian community structure and breeding utilization of artificial pools created on an abandoned pyrite mine site in Prince William County, Virginia.

摘要

Ten artificial pools created as a result of the Cabin Branch Pyrite Mine Reclamation Project were studied to assess the effect low pH and heavy metal concentrations had on amphibian community structure and breeding success. Study results indicated that six sites (A, B, G, H, I, and J) were significantly affected by elevated aluminum, cadmium, copper, and zinc concentrations, as well as low pH. Multiple heavy metal concentrations exerted an additive effect, producing significant amphibian mortality and lack of reproductive success. All sites, including the control site (K), had Al levels above the Environmental Protection Agency Criterion Continuous Concentrations Standard (EPA CCC); however, only four sites (G, H, I, and J) had pH levels that contributed significantly to Al toxicity. Three sites (C, D, and E) with levels of Cd, Cu, and Zn below EPA CCC, showed evidence of building amphibian communities comparable to the control site (K).; Hyla chrysoscelis eggs showed a much higher tolerance for Cd, Cu, and Zn than has been previously documented, suggesting that they have adapted well to this highly disturbed environment. Bufo americanus exhibited high tolerance levels for Cu and Pb (approximately 23 and 76mug/l, respectively), surviving to transformation. This represents the first Cu and Pb toxicity documentation for this species. H. chrysoscelis also showed a high tolerance for Pb, reproducing successfully in concentrations as high as 76mug/l; the first reported Pb toxicity documentation for this species. Ambystoma maculatum was only observed in sites with the best water quality (D, E, and K), suggesting that this species was less tolerant of heavy metals than indicated in the literature. Species richness and diversity were clearly influenced by the environment, with Shannon Indices of two sites (C and D) most closely matching the control site and differing from the remaining sites.; This study clearly illustrates that community structure is affected by the presence of low pH and high concentrations of heavy metals, and that multiple metals exhibit an additive effect that substantially reduces reproductive success and survivorship of amphibians.