How do vernal pond temperature fluctuations impact fitness through development?

How do vernal pond temperature fluctuations impact fitness through development?

Anthropogenic climate change is driving shifts in natural temperature regimes. In addition to global warming, temperatures are becoming increasingly variable. Many organisms rely on seasonal temperatures across life stages as they grow and reproduce, among other critical aspects of their lives. A lot of work has been done on how increases in mean temperature might impact organisms, but there is a gap in our understanding on the impacts of increases in variation. Amphibians are especially susceptible to environmental change, particularly in earlier life stages. Increases in temperature have been shown to cause shifts in their phenology, decreases in body size, and an increase in premature mortality. The purpose of my work is to collect data on natural temperature variance and salamander growth, survival, and abundance in ponds across central Kentucky and southern Indiana. Spotted salamanders (Ambystoma maculatum) are widespread across the eastern United States and develop from egg to adult in one year. Their developmental timing will allow me to follow populations from egg to larvae to metamorphosis in a realistic experimental setting. I will visit ponds monthly to measure pond temperature, pH, invertebrate communities, and salamander presence, size, and waterborne stress hormone (corticosterone) levels. I anticipate that the results will show that higher and more variable temperature will lead to lower survival and body size, as well as increased expression of stress hormones, of the salamanders pre- and post-metamorphosis. The results from this experiment will inform us on natural pond variation in this region and help to illustrate how spotted salamanders are reacting to shifts in temperature regimes. Once we have more of an understanding of how spotted salamanders are being impacted, we can work to implement conservation strategies.