Metal accumulation in bobcats in the Southeastern USA.

Abstract

Bobcats (Lynx rufus) are wide-ranging mammals found throughout the continental USA. As carnivores near the top of their food chain, bobcats would seem to be a useful bioindicator of metal pollution in terrestrial environments. However, there is very limited research on bobcats in toxicology studies. Here, we offer the first analysis of metal (copper, selenium, silver, and zinc) contaminants in the livers of wild bobcats. Liver tissues from 120 adult bobcats (i.e., estimated to be ≥1year old) were collected from 2003 to 2006 at four sites in Georgia and Florida, USA that experienced relatively similar levels of human disturbance. We found no differences in metal concentrations between males and females. At two of the sites sampled over three consecutive years, there was substantial year-to-year variation in the concentrations of Cu, Se, and Zn. We also documented some variation between sites, but only between sites sampled in different years, which may reflect additional temporal, rather than spatial, variation. Concentrations of Cu and Ag were significantly positively correlated with one another, as were concentrations of Se and Zn. Contrary to expectation, there were no significant relationships between body weight and metal concentrations. Finally, comparison with results from previous metal toxicology studies of nine-banded armadillos (Dasypus novemcinctus) and Virginia opossums (Didelphis virgianus), collected from the same sites during the same years, showed differential patterns of accumulation across species, suggesting that ecological lifestyle is an important influence on metal accumulation. This study provides reference levels of metal contaminants in the liver of bobcats as well as insight into metal accumulation in a top level carnivore.