Publication Date

Fall 2016

Advisor(s) - Committee Chair

Jarrett R. Johnson (Director), Philip W. Lienesch, Carl W. Dick

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

In terrestrial habitats with a history of mining activity and previous or ongoing reclamation efforts, understanding the effects of acidification on the ecology of amphibians is an important part of the restoration process and the conservation of local amphibian populations. Pond-breeding amphibians spend much of their post metamorphic life history in direct contact with the soil in upland habitat adjacent to aquatic breeding sites. I reared recently metamorphosed marbled salamanders (Ambystoma opacum) to evaluate the role of soil acidity on determinants of fitness such as growth and survival. My results indicate that a substrate of pH 4 was lethal to recent A. opacum metamorphs. Among animals surviving the higher pH treatments, we found that individuals reared on a pH 5 substrate suffered a reduction in total length and snout vent length by the end of the experiment.

The mechanisms of acidity are complex; both hydrogen ions and anions contribute to negative effects on amphibians. Sulfuric acid has larger negative effects than other acids and sulfates can cause reductions in growth without a change in pH. I reared larval spotted (Ambystoma maculatum) and Jefferson salamanders (Ambystoma jeffersonianum) to evaluate the effects of pH and sulfates on two species with differential acid resistances. My results indicate that a pH of 4 is lethal to larval salamanders of both species. In high sulfate treatments there was an early reduction in growth in the spotted salamander, but not in the Jefferson salamander showing that acid resistance applies to the effects of sulfates as well as hydrogen ions. Together, our results suggest that acid and sulfate deposition can affect the fitness of Ambystoma salamanders through direct mortality and a decrease the growth rate of salamanders both as larvae and subsequent to metamorphosis.

Disciplines

Developmental Biology | Natural Resources and Conservation | Zoology

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