What to eat in a warming world do increased temperatures necessitate hazardous duty pay?

• Published in: Oecologia Vol. 186; no. 1; pp. 73 - 84
• Main Authors: Hall, L. Embere, Chalfoun, Anna D.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Science + Business Media 01.01.2018; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Availability; BEHAVIORAL ECOLOGY – ORIGINAL RESEARCH; Biomedical and Life Sciences; Biomes; Climate change; Ecology; Exposure; Food; Food availability; Food composition; Food quality; Food selection; Foods; Forage; Foraging; Foraging behavior; Global temperature changes; Hydrology/Water Resources; Hypotheses; Interspecific relationships; Life Sciences; Nitrogen; Ochotona princeps; Plant Sciences; Predation; Quality; Resource availability; Sensors; Temperature; Temperature effects; Temperature preferences; Temperature sensors; Vegetation; Thermoregulatory risk; Resource selection; Climate change; Forage choice; Ochotona princeps
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s00442-017-3993-2

Contemporary climate change affects nearly all biomes, causing shifts in animal distributions and resource availability. Changes in resource selection may allow individuals to offset climatic stress, thereby providing a mechanism for persistence amidst warming conditions. Whereas the role of predation risk in food choice has been studied broadly, the extent to which individuals respond to thermo-regulatory risk by changing resource preferences is unclear. We addressed whether individuals compensated for temperature-related reductions in foraging time by altering forage preferences, using the American pika (Ochotona princeps) as a model species. We tested two hypotheses: (1) food-quality hypothesis—individuals exposed to temperature extremes should select higher-quality vegetation in return for accepting a physiologically riskier feeding situation; and (2) food-availability hypothesis—individuals exposed to temperature extremes should prioritize foraging quickly, thereby decreasing selection for higher-quality food. We quantified the composition and quality (% moisture, % nitrogen, and fiber content) of available and harvested vegetation, and deployed a network of temperature sensors to measure in situ conditions for 30 individuals, during July–Sept., 2015. Individuals exposed to more extreme daytime temperatures showed increased selection for high-nitrogen and for low-fiber vegetation, demonstrating strong support for the food-quality hypothesis. By contrast, pikas that experienced warmer conditions did not reduce selection for any of the three vegetation-quality metrics, as predicted by the food-availability hypothesis. By shifting resource-selection patterns, temperature-limited animals may be able to proximately buffer some of the negative effects associated with rapidly warming environments, provided that sufficient resources remain on the landscape.