@article{lafferty_zimova_clontz_hacklander_mills_2019, title={Noninvasive measures of physiological stress are confounded by exposure}, volume={9}, ISBN={2045-2322}, DOI={10.1038/s41598-019-55715-5}, abstractNote={Abstract Glucocorticoids and glucocorticoid metabolites are increasingly used to index physiological stress in wildlife. Although feces is often abundant and can be collected noninvasively, exposure to biotic and abiotic elements may influence fecal glucocorticoid metabolite (FGM) concentrations, leading to inaccurate conclusions regarding wildlife physiological stress. Using captive snowshoe hares ( Lepus americanus ) and simulated environmental conditions, we evaluated how different realistic field conditions and temporal sampling constraints might influence FGM concentrations using an 11-oxoetiocholanolone-enzyme immunoassay. We quantified how fecal pellet age (i.e., 0–6 days), variable summer temperatures, and precipitation affected FGM concentrations. Fecal pellet age had a strong effect on FGM concentrations (β Age = 0.395, s.d. = 0.085; β 2 Age = −0.061, s.d. = 0.012), which were lowest at the beginning and end of our exposure period (e.g., mean day6 = 37.7 ng/mg) and typically highest in the middle (mean day3 = 51.8 ng/mg). The effect of fecal pellet age on FGM concentrations varied across treatments with warm-dry and cool-wet conditions resulting in more variable FGM concentrations relative to control samples. Given the confounding effects of exposure and environmental conditions, if fresh fecal pellet collection is not an option, we encourage researchers to develop a temporally consistent sampling protocol to ensure all samples are exposed to similar environmental conditions.}, journal={SCIENTIFIC REPORTS}, author={Lafferty, Diana J. R. and Zimova, Marketa and Clontz, Lindsay and Hacklander, Klaus and Mills, L. Scott}, year={2019} }
 @article{zimova_hacklaender_good_melo-ferreira_alves_mills_2018, title={Function and underlying mechanisms of seasonal colour moulting in mammals and birds: what keeps them changing in a warming world?}, volume={93}, ISSN={["1469-185X"]}, DOI={10.1111/brv.12405}, abstractNote={Animals that occupy temperate and polar regions have specialized traits that help them survive in harsh, highly seasonal environments. One particularly important adaptation is seasonal coat colour (SCC) moulting. Over 20 species of birds and mammals distributed across the northern hemisphere undergo complete, biannual colour change from brown in the summer to completely white in the winter. But as climate change decreases duration of snow cover, seasonally winter white species (including the snowshoe hare Lepus americanus, Arctic fox Vulpes lagopus and willow ptarmigan Lagopus lagopus) become highly contrasted against dark snowless backgrounds. The negative consequences of camouflage mismatch and adaptive potential is of high interest for conservation. Here we provide the first comprehensive review across birds and mammals of the adaptive value and mechanisms underpinning SCC moulting. We found that across species, the main function of SCC moults is seasonal camouflage against snow, and photoperiod is the main driver of the moult phenology. Next, although many underlying mechanisms remain unclear, mammalian species share similarities in some aspects of hair growth, neuroendocrine control, and the effects of intrinsic and extrinsic factors on moult phenology. The underlying basis of SCC moults in birds is less understood and differs from mammals in several aspects. Lastly, our synthesis suggests that due to limited plasticity in SCC moulting, evolutionary adaptation will be necessary to mediate future camouflage mismatch and a detailed understanding of the SCC moulting will be needed to manage populations effectively under climate change.}, number={3}, journal={BIOLOGICAL REVIEWS}, author={Zimova, Marketa and Hacklaender, Klaus and Good, Jeffrey M. and Melo-Ferreira, Jose and Alves, Paulo Celio and Mills, L. Scott}, year={2018}, month={Aug}, pages={1478–1498} }
 @article{mills_bragina_kumar_zimova_lafferty_feltner_davis_hacklaender_alves_good_et al._2018, title={Winter color polymorphisms identify global hot spots for evolutionary rescue from climate change}, volume={359}, ISSN={["1095-9203"]}, DOI={10.1126/science.aan8097}, abstractNote={Changing coats with the season Many species of mammals and birds molt from summer brown to winter white coats to facilitate camouflage. Mills et al. mapped global patterns of seasonal coat color change across eight species including hares, weasels, and foxes. They found regions where individuals molt to white, brown, and both white and brown winter coats. Greater proportions of the populations molted to white in higher latitudes. Regions where seasonal coat changes are the most variable (molting to both brown and white) may provide resilience against the warming climate. Science, this issue p. 1033 Variation in winter coat color may protect species with winter camouflage—such as hares, weasels, and foxes—when the climate warms. Maintenance of biodiversity in a rapidly changing climate will depend on the efficacy of evolutionary rescue, whereby population declines due to abrupt environmental change are reversed by shifts in genetically driven adaptive traits. However, a lack of traits known to be under direct selection by anthropogenic climate change has limited the incorporation of evolutionary processes into global conservation efforts. In 21 vertebrate species, some individuals undergo a seasonal color molt from summer brown to winter white as camouflage against snow, whereas other individuals remain brown. Seasonal snow duration is decreasing globally, and fitness is lower for winter white animals on snowless backgrounds. Based on 2713 georeferenced samples of known winter coat color—from eight species across trophic levels—we identify environmentally driven clinal gradients in winter coat color, including polymorphic zones where winter brown and white morphs co-occur. These polymorphic zones, underrepresented by existing global protected area networks, indicate hot spots for evolutionary rescue in a changing climate.}, number={6379}, journal={SCIENCE}, author={Mills, L. Scott and Bragina, Eugenia V. and Kumar, Alexander V. and Zimova, Marketa and Lafferty, Diana J. R. and Feltner, Jennifer and Davis, Brandon M. and Hacklaender, Klaus and Alves, Paulo C. and Good, Jeffrey M. and et al.}, year={2018}, month={Mar}, pages={1033–1036} }