Frog and Toad Habitat Occupancy across a Polychlorinated Biphenyl (PCB) Contamination Gradient
A major challenge in amphibian ecotoxicology is understanding the population-level implications of laboratory-based, dose-response studies. We contrasted habitat occupancy among five species of frogs and toads in two adjacent segments of the upper Hudson River—one heavily contaminated by polychlorinated biphenyls (PCBs, compounds reported to have adverse impacts on individual amphibians) and the other uncontaminated—while controlling for site and sampling covariates. Site occupancy was estimated via repeated night call surveys at 40 wetland sites during 2006 and 2007. Habitat occupancy varied strongly in response to whether breeding sites were hydrologically connected to the Hudson River but was independent of the degree of PCB contamination of a given river segment. The results highlight the uncertainties of extrapolating outcomes of laboratory-based, toxicological studies to wild amphibian populations.Abstract

Sites where calling frogs and toads were sampled to assess habitat occupancy across a PCB-contamination gradient associated with the upper Hudson River during 2006 and 2007.
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