The Effects of Road Salt on Spotted Salamanders (Ambystoma maculatum) and Wood Frogs (Lithobates sylvaticus)

The majority of the United States employs the use of road de-icing salts - primarily NaCl- during the winter and early spring months. As a result, much of the runoff from roads into roadside and forested vernal pools contains road de-icing salts. Many amphibian species live at least a portion of their lives in these vernal ponds, including spotted salamanders (Ambystoma maculatum) and wood frogs (Lithobates sylvaticus). Because amphibians are the most threatened group of vertebrates and are important biotic elements of both terrestrial and aquatic ecosystems, it is crucial to determine the impact of road salt on amphibians. We hypothesized that salt would delay hatching in both amphibian species. Additionally, we hypothesized that salt would negatively affect predatory insects, thus decreasing predation on both species. Lastly, we predicted that salt would increase competition between the two species by reducing the amount of invertebrates available for consumption. During the spring and the summer of 2017, we conducted an outdoor mesocosm experiment in which we created eight experimental conditions: presence/absence of NaCl (1000 mg/L Cl-), presence/absence of interspecific competition between the two species, and presence/absence of predatory dragonfly nymphs (Family Libellulidae). So far, our experiment has revealed that salt delayed hatching and increased deformity in spotted salamander hatchlings. Additionally, we have found that salt increases tail size in wood frog tadpoles. Overall, our data suggest that the application of road de-icing salt has many far-reaching impacts on amphibians and their ecosystem