Thermal diversity affects community responses to warming

Scientists often use an exponential equation to model the responses of community metabolic rates to temperature, which however contradicts with the fact that the temperature performance curves of individual species are unimodal, and ignores the difference between intraspecific and interspecific temperature sensitivity. To address these issues, species thermal diversity needs to be considered. To explore how thermal diversity affects community temperature responses, I construct a nutrient-phytoplankton–zooplankton (NPZ) model in which phytoplankton is represented by multiple species with different temperature performance curves. Each curve is determined by a master thermal trait, optimal temperature. I then create two levels of phytoplankton thermal diversity by varying the zooplankton prey density-dependent feeding preference (if zooplankton prefers to feed on abundant prey, prey diversity is enhanced). I find that the responses of the community productivity to temperature is dampened at high diversity compared to low diversity, due to the lower interspecific temperature sensitivity than the intraspecific one. High thermal diversity also confers the community a better capacity to track the environmental temperature fluctuation and withstand high temperature inhibition. In addition, thermal diversity increases community mean optimal temperature. I propose that the community temperature sensitivity is not static and urge that distributions of thermal traits of natural assemblages ought to be measured.