Meeting Abstract
While correlations among risk of extinction, genetic variability, and physiological stress are widely assumed, few studies have directly measured the relationships among these indices of population fitness. Working within a theoretical framework of species range dynamics, we aim to test whether independent assessments of habitat quality, generated from spatially-explicit ecological niche models (ENM), correlate with neuroendocrine and genetic indicators of population-level health within the eastern range of the wood frog (Lithobates sylvaticus). During the 2011 breeding season, we sampled males from 20 populations, which spanned the latitudinal range of the eastern clade of wood frogs and were located within a range of habitat qualities as predicted by a climate-based ENM. We also sampled males from roadside and woodland breeding sites within select climatic regions to resolve the impact of local habitat conditions stress responsiveness of populations. For each population, we measured baseline plasma corticosterone (CORT) and testosterone concentrations and CORT responsiveness to a standard dose of ACTH. Based on findings from laboratory experiments, we predicted that baseline CORT will be higher and ACTH-responsiveness lower in areas of lower habitat quality. We also recorded body measurements, reproductive deformities, and assayed for chytrid, ranavirus, and trematode infections. We also measured individual and population-level genetic variability using microsatellite markers. Ultimately, we will integrate these broad and fine-scaled measures of population fitness to understand the geography of population health, how species are distributed in space, and how these distributions will be altered by environmental change.
