LAUSR

The ability of organisms to respond adaptively to anthropogenic environmental change is behaviorally mediated, and recent studies indicate that anthropogenic acidification impairs behavioral responses by impacting olfactory abilities of aquatic organisms. The effect on behavior of other stressors, such as plant secondary compounds, in concert with low pH, has not been investigated. In this study we sought to a) determine whether the oviposition site choices of adult female Cope's Gray Treefrogs (Hyla chrysoscelis) correspond with the pH and tannin conditions that maximize tadpole survival and performance in the laboratory and b) investigate the impacts of mildly acidic conditions, with and without the added stress of tannins, on the survival, development, and antipredator behavior of this frog's tadpoles. We conducted a field oviposition experiment to determine adult female site choice and reared tadpoles in acidic and tannic conditions to investigate survival and antipredator behaviors. Female oviposition site choice did not correspond with conditions that maximize offspring survival. Acidity did not reduce embryonic (pH = 4.5, 5.5) or larval (pH = 5.5) survival. Tadpole mortality was highest in tannic treatment, yet this treatment received the second most eggs in the oviposition experiment. Some aspects of tadpole antipredator behavior in mildly acidic conditions suggested impaired predator recognition, though this difference was not statistically significant. Tannic conditions appear to have the greatest negative effect on tadpole fitness, and adult females appear to respond maladaptively when offered pools with a tannin concentration likely to be created by some invasive exotic wetland plants.