Meeting Abstract

114.1  Saturday, Jan. 7  Is plasma corticosterone a useful biomarker of environmental degradation? WOODLEY, S.K.*; RICCIARDELLA, L.F.; Duquesne University; Duquesne University

Amphibians are declining throughout the world due to many factors. One source of environmental degradation impacting amphibian populations in Pennsylvania is stream acidification. We asked whether sublethal exposure to acidified environments was associated with elevated plasma corticosterone (CORT), an important mediator of the vertebrate stress response. We sampled baseline and handling-induced increases in plasma CORT in male stream-side salamanders (Desmognathus ochrophaeus) from 13 populations representing an acid-alkaline gradient from pH of 4.1 to 8.1. A previous study had found decreased abundance and diversity of salamanders in acidified sites. We found no effect of acidification on plasma CORT levels. Likewise, a study in the laboratory found similar plasma CORT in subjects exposed to acid versus acid-neutral conditions. However, captive subjects previously exposed to an acidified environment had decreased activity compared to subjects previously exposed to an acid-neutral environment. Together, these results indicate that environmental acidification resulted in behavioral changes that were not associated with endocrine changes. Thus, measurement of plasma and stress-induced CORT is not a useful biomarker of environmental acidification in stream-side salamanders.