Development of Spotted Salamanders When Faced with Pollution and Predation

Salt (NaCl) pollution from salting roads during the winter has been more disruptive in ecosystems, particularly in freshwater aquatic ecosystems in which various amphibian species breed. The spotted salamander (Ambystoma maculatum) in particular has been found to be affected by this salt pollution, showing delayed hatching or deformities. Their egg clutch is surrounded by multiple gelatinous layers. These layers are often eaten away by predators such as wood frog tadpoles (Lithobates sylvaticus), exposing the salamander embryos to the environment. Thus, the presence of wood frog tadpoles may exacerbate the effect of salt pollution on the salamander embryos. In spring 2018, we conducted a laboratory experiment with a factorial design involving the presence or absence of road salt, wood frog tadpoles, and jelly layers surrounding the salamander eggs. Daily, we monitored hatching and mortality of the salamander embryos and also measured body length and developmental stages of hatchlings. We predicted that the presence of salt, presence of predators, and the absence of a jelly layer would cause greater mortality and earlier hatching in salamanders that would also result in less developed hatchlings. Preliminary data analyses show that the presence of wood frog tadpoles decreased hatching success while the presence of jelly layers also decreased the hatching success of the salamanders. Both salt pollution and the presence of jelly layers increased the incubation period. These preliminary results suggest that while salt pollution negatively affected the development of the salamanders, it did not interact with the other variables such as the presence/absence of predatory tadpoles and the presence/absence of jelly layers