Warming and Resource Availability Shift Food Web Structure and Metabolism

TLDR

Climate change disrupts ecosystems, and while species‑specific life histories complicate predictions, metabolic responses to temperature across trophic levels suggest that warming can predictably alter food‑web structure and productivity. The authors experimentally examined how warming affects food‑web structure and productivity under high and low resource supply scenarios. They found that warming enhanced consumer control of primary production and reshaped food webs—reducing total biomass despite higher primary productivity under high resources, while low resources limited production at all temperatures—demonstrating that modest temperature shifts can dramatically alter ecosystem dynamics in a species‑independent way.

Abstract

Climate change disrupts ecological systems in many ways. Many documented responses depend on species' life histories, contributing to the view that climate change effects are important but difficult to characterize generally. However, systematic variation in metabolic effects of temperature across trophic levels suggests that warming may lead to predictable shifts in food web structure and productivity. We experimentally tested the effects of warming on food web structure and productivity under two resource supply scenarios. Consistent with predictions based on universal metabolic responses to temperature, we found that warming strengthened consumer control of primary production when resources were augmented. Warming shifted food web structure and reduced total biomass despite increases in primary productivity in a marine food web. In contrast, at lower resource levels, food web production was constrained at all temperatures. These results demonstrate that small temperature changes could dramatically shift food web dynamics and provide a general, species-independent mechanism for ecological response to environmental temperature change.