Meeting Abstract
Integration of physiological mechanism and the timescales over which they act can improve our ecological predictions under warming scenarios. The timescale over which stressors are experienced and the duration of the stress response they produce, influence the ecological capacities of an organism through alteration in energy allocation regimes. Organisms face challenges from warming, drying, variable temperatures, and fluctuations in vapor pressure deficits. Yet, interactions between these factors are often ignored. The natural gradients of temperature and humidity in the Southern Appalachian Mountains allow for the use of space for time substitutions to study to effect of climate on terrestrial salamander stress responses. To test for geographic variation of stress, we collected woodland salamanders from the latitudinal and elevational extent of their range. We obtained blood and fecal samples from each individual and analyzed leukocyte ratios and fecal corticosterone levels as metrics of stress. We compared findings to fine-scale environmental data over varying timescales. Leukocyte ratios indicated greater stress with drier air for all individuals, and with warmer temperatures for small individuals. Fecal corticosterone levels do not correlate to leukocyte ratios, suggesting the time course over which stressors interact are important to the physiological response Plethodon species may mount in response to changes in climate. These findings indicate geographic areas where range contractions may occur due to increases in both the mean and the frequency of abiotic stressors.
