Date of Award

1-2014

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Lisa Hazard

Committee Member

John Smallwood

Committee Member

Scott Kight

Abstract

Amphibians are highly susceptible to environmental degradation in the form of pollution and are therefore considered an indicator for pollutants. Amphibian populations have been on the decline in recent years and possible causes have been subject of much recent research. One possible contributor to the decline is the effect of the use of road de-icing salts on the availability of viable habitat choices. Road salt, primarily NaCl, is one of the leading contributors of chloride in aquatic environments in northern climates. Salt from road run-off has the ability to affect amphibians directly by causing a reduction in offspring fitness, resulting in mortality or deformities in embryos and juveniles. Secondarily, it has the ability to affect the behavior of adult amphibians during breeding site selection. Few studies have focused on the secondary effects of salt on the behavior of amphibian species. Furthermore, still fewer have delved into the possibility of adaptation of different populations to salt stressors, enabling frogs to tolerate the higher salt concentrations of their surrounding habitat. This study focused on quantifying the behavior of adult Spring Peepers, Pseudacris crucifer, in the presence of a saline water. Peepers preferred lower salt concentrations, but may require more than a few minutes to detect and respond to salt in water, especially at low to moderate levels. As salt concentrations increased, there was a greater loss of mass in the frogs. Ultimately, the frogs showed preference for salinities that were around or below their own osmolarity and strong aversion to high salt solutions. High salt concentrations in vernal pools attributed to by road salt run off could cause a shift in breeding behavior and/or migration to less polluted pools. Salinized water has been implicated in the increase of deformities and increased mortality during the embryonic and larval stages. Both of these responses to salt pollution, acting synergistically, could lead to local extirpation of sensitive amphibian species.

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