Honey We Shrunk the World: Climate Change and Shrinking Salamanders in Palouse Prairie Wetlands

Primary author: Erim Gomez
Co-author(s): Rodney Sayler
Faculty sponsor: Rodney Sayler

Primary college/unit: Agricultural, Human and Natural Resource Sciences
Campus: Pullman


Global warming is projected to reduce the future body size of many species among mammals, birds, and amphibians. Plethodontid (lungless) salamanders are particularly susceptible to the effects of warming temperatures and environmental desiccation because adults require moist skin for respiration. We studied growth dynamics of long-toed salamanders (Ambystoma macrodactylum) originating from 27 Palouse Prairie wetlands to evaluate the working hypothesis that growth was influenced by wetland hydroperiod (duration of flooding) and that larval salamanders in ephemeral wetlands that dried up in summer would be forced to undergo metamorphosis more quickly and emerge onto land at a smaller adult body size compared to larvae occupying more permanent wetlands that allow longer developmental periods. We used machine-learning modeling techniques to compare the size and growth of larvae and adults among wetlands and found that larval size distributions were smaller in shallow, ephemeral wetlands and larger in permanent wetlands and artificial ponds that retained water throughout summer. In addition, statistical models for adult structural size and weight reveal that even after two seasons of growth in captivity with ad libitum food, adult salamanders originating from ephemeral ponds still remained smaller and lighter on average than salamanders originating from permanent wetlands. If future climate change shortens wetland hydroperiods, it may result in reductions in salamander body size and possibly contribute to higher mortality and reduced reproductive success and fitness in salamander populations in Palouse Prairie wetlands.