Temperature and predators as interactive drivers of community properties

Abstract

The effects of warming on ecological communities emerge from a range of potentially asymmetric impacts on individual physiology and development. Understanding these responses, however, is limited by our ability to connect mechanisms or emergent patterns across the many processes that drive variation in demography. Further complicating this understanding is the gain or loss of predators to many communities, which may interact with changes in temperature to drive community change. Here we conducted a factorial warming and predation experiment to test generalized predictions about responses to warming. We used microcosms with a range of protists, rotifers, and a gastrotrich, with and without the predator Actinosphaerium, to assess changes in diversity, body size, function, and composition in response to warming. We find that community respiration and predator:prey biovolume ratios peak at intermediate temperatures, while species richness declined with temperature. We also found that overall biomass increased with species richness, driven by the effect of temperature on richness. There was little evidence of an interaction between predation and temperature change, likely because the predator was mostly limited to the intermediate temperatures. Overall, our results suggest that general predictions about community change are still challenging to make but may benefit by considering multiple dimensions of community patterns in an integrated way.

Species interactions and food-web context drive temperature-dependent prey evolution

“…Temperature-mediated changes in species interactions drive changes in species plastic and evolutionary functional traits (Barbour & Gibert 2021;Fischer et al 2016;Fordyce 2006), which in turn can reshape food web dynamics, structure, and function (Bartley et al 2019;DeLong et al 2023;Gibert 2019;Han et al 2023;Lister & Garcia 2018;Petchey et al 1999;Thakur et al 2018). As warming increases extinction rates among predators (Thunell et al 2021;Voigt et al 2003;Zarnetske et al 2012), a decrease in predator diversity might also lead to decreases in prey trait diversity that may result in disproportionate effects from more dominant predators and increased loss of genetic diversity within prey populations.…”