Stable Isotope and Trace Element Studies of Black Bear Hair, Big Bend Ecosystem, Texas and Mexico

Product Type: Report, Pages In

Year: 2008

Author(s): Shanks, III, W.C.P., E.C. Hellgren, C. Stricker, P.A. Gemery-Hill, and D.P. Onorato

Pages: 77-84

Suggested Citation: Shanks, III, W.C.P., E.C. Hellgren, C. Stricker, P.A. Gemery-Hill, and D.P. Onorato. 2008. Stable Isotope and Trace Element Studies of Black Bear Hair, Big Bend Ecosystem, Texas and Mexico. In: J.E. Gray and W.R. Page (eds.). Geological, Geochemical, and Geophysical Studies by the U.S. Geological Survey in Big Bend National Park, Texas. Circular 1327. : U.S. Geological Survey. 77-84 p.

Abstract

Hair from black bears (Ursus americanus), collected from four areas in the Big Bend ecosystem ,has been analyzed for stable isotopes of carbon, nitrogen, and sulfur to determine major food sources and for trace metals to infer possible effects of environmental contaminants. Results indicate that black bears are largely vegetation, feeding on desert plants, nuts, and berries. Mercury concentrations in bear hair are below safe level standards, and other trace metal concentrations are generally below levels that have been associated with adverse affects in other mammals. These results indicate low potential for negative health affects on bears due to trace element contaminants in the Big Bend ecosystem.