Amphibians are experiencing worldwide declines and disappearing at an alarming rate. Recent calculations report the extinction rate could be greater than 211 times the background rate Declines are occurring worldwide rapidly with entire clades of species threatened with extinction, with each analysis the future for amphibians is becoming more and more grim. While it is clear that the majority of amphibian populations are experiencing stress there are few ways to determine the actual stress level within individuals. For larger animals fecal and or blood samples have been shown to determine an individual’s glucocorticoid level or stress level, but these methods cannot be used for amphibians, especially terrestrial species. Amphibian fecal is often small and almost impossible to find and small terrestrial species would not survive a blood draw to test for stress. We found a way to modify current non-invasive water borne assays to determine stress levels in small terrestrial salamanders. Salamanders were placed in a 20mL water bath for an hour to collect water-borne hormones, each salamander was then measured, weighed, sexed and notes on condition were taken. Corticosterone levels were determined using an EIA kit with the water samples collected from each individual.
Results/Conclusions
The goal of this preliminary study was to determine if corticosterone (CORT) levels could be determined using water-borne assays in small terrestrial species. Every sample came back with some level of CORT in the sample. Trends are currently being examined since there were statistically significant differences in the CORT values between the individuals. The individuals sampled were found within a multi-year cover board study site on the Patuxent Wildlife Research Refuge. Every individual found within the cover board plots have been given a unique individual identification mark with visible implant elastomer and size and condition is recorded for every captured individual six times a year (three times in the spring and three times in the fall). Using this history, possible trends are being examined between CORT levels and plot density, sex, days since last capture and number of captures to determine what could be causing the significant difference in CORT levels between individuals. Being able to determine CORT levels non-invasively gives insight into what stressors local populations’ maybe struggling with and can help create successful management practices. CORT levels are key to conservation physiology and can give insight into the ecology of the landscape, and the status of a population.