Magnitude-duration relationships of physiological sensitivity and environmental exposure improve climate change vulnerability assessments

Integrating thermal physiology with environmental temperature is essential to understanding distributions of species and vulnerability to climate change. Warming tolerance—the difference between an organism’s maximum thermal tolerance (Tmax) and maximum habitat temperature (Thab)—is frequently used to integrate organismal sensitivity and environmental exposure. Traditionally, applications of warming tolerance define Tmax and Thab as invariable magnitudes, yet tolerance magnitude depends on exposure duration and diel temperature cycles expose organisms to a range of temperature magnitudes and durations. How traditional (i.e., acute) estimates of warming tolerance compare to estimates from prolonged exposures remains poorly understood. In this study, magnitude-duration curves for tolerances of one cold-water, two cool-water, and one warm-water species of freshwater fish were compiled from the literature and compared to magnitude-duration exposures from 66 streams across the eastern United...