Metal Bioaccumulation and Assemblage Attributes for Anurans in the Sierra de Huautla Biosphere Reserve, Mexico

Abstract

Background and Research Aims: Morphological and physiological effects of anthropogenic metals have been the focus of several studies in the Sierra de Huautla Biosphere Reserve (REBIOSH, Mexico) but little is known about how they affect anurans in the area. We evaluated metal bioaccumulation in anurans from streams in the REBIOSH and examined anuran communities in five sites at different positions relative to abandoned mine tailings. Methods: Three and two sites were located upstream and downstream from mine tailings, respectively. We collected anuran community information and obtained sediment, water and liver samples for metal quantification from each site. Results: Concentrations of Cu, Pb, Zn and Mn in water, and Zn, Mn, Fe and Cr in sediment, were significantly different among sites. We found bioaccumulation of Pb, Zn and Fe in livers of Smilisca baudinii, Lithobates spectabilis, L. zweifeli and Rhinella horribilis, species with different life traits. We found similar among-site species richness and diversity. Communities were dominated by L. zweifeli, R. horribilis and S. baudinii. Dominance was highest in sites distant from mine tailings. Agalychnis dacnicolor, Tlalocohyla smithii and Hypopachus variolosus were only present in sites located closest to mine tailings. Conclusion: We did not detect an effect of metal bioacummulation on anuran communities, but our findings suggest a potential effect on certain species in the protected area. Our results form a baseline for future explorations of the impacts of metals in the region. Implications for Conservation: Toxic metal bioaccumulation has potential for reducing anuran genetic variability and altering sexual proportions and fecundity, potentially leading to anuran extirpations. We provide first evidence for metal bioaccumulation in anurans in the protected area, and one of few studies on its anuran communities. Our evidence can serve as guidance to ameliorate effects of legacy metal mining in this biodiversity hotspot.