The Effects Of Acidic Conditions And Tannins On The Survival, Development, And Behavior Of Cope’s Gray Treefrog (Hyla Chrysoscelis)

As amphibians decline around the world, freshwater acidification resulting from pollutants and acid rain may be a contributor. The ability of organisms to cope with environmental changes is greatly mediated by behavior, and recent studies indicate that anthropogenic acidification impairs behavioral responses by impacting olfactory abilities of aquatic organisms. Responding appropriately to novel stimuli is important for individual performance and survival, and pollutants may cause organisms to behave maladaptively. In this study I sought to: a) determine whether the oviposition site choices of adult female frogs 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 anti-predator behavior of Hyla chrysoscelis tadpoles. I conducted a field oviposition study to determine adult female site choice, and reared tadpoles in acidic and tannic conditions to investigate survival and antipredator behaviors. I found that female oviposition site choice did not correspond with conditions that maximize offspring survival. Tadpole mortality was highest in tannic treatments, yet tannic treatments received a high proportion of eggs in the oviposition experiment. Trends in tadpole antipredator behaviors suggested that mildly acidic conditions impaired predator recognition, though this was not statistically significant. My results suggest that tannic conditions reduce tadpole fitness, yet adult females appear to respond maladaptively to elevated tannins by failing to avoid tannic treatments when ovipositing