Meeting Abstract
Amphibian declines in the agricultural landscape are driven by many factors. However, a greater understanding of the relative impact of individual factors, and interspecific sensitivity to known drivers of amphibian decline is needed. In this study two amphibian species, American bullfrogs (Lithobates catesbeianus) and Northern leopard frogs (Lithobates pipiens), were exposed to a mixture of agrochemicals for 12 days. The American bullfrog is an invasive species with relatively stable populations in California, USA, while the Northern leopard frog is native to California but has experienced dramatic population declines at nearly all historic locations within the state. Our agrochemical mixture represented commonly applied pesticides and fertilizers in California, to which both native and invasive species inhabiting the agricultural environment are likely exposed. The mix included glyphosate isopropylamine salt, oxyfluorfen, chlorpyrifos, pendimethalin, paraquat dichloride, glufosinate-ammonium, maneb, propanil, trifluralin, 2,4-D dimethylamine salt, nitrates, and phosphates. Following exposure, plasma corticosterone and immune cell responses were examined. Given the ubiquitous presence of aquatic contamination and the importance of disease in global amphibian declines, this study may assist in prioritizing threats to the survival of sensitive native amphibians and address the relevance of invasive amphibian species as surrogate models for the impacts of contaminant exposure on a native amphibian species.
