Predation Risk Reverses the Potential Effects of Warming on Plant-Herbivore Interactions by Altering the Relative Strengths of Trait- and Density-Mediated Interactions.

Predation Risk Reverses the Potential Effects of Warming on Plant-Herbivore Interactions by Altering the Relative Strengths of Trait- and Density-Mediated Interactions.
Am Nat. 2017 Sep;190(3):337-349
Authors: Lemoine NP
Abstract
Climate warming will initiate numerous changes in ecological community structure and function, and such high-level impacts derive from temperature-driven changes in individual physiology. Specifically, top-down control of plant biomass is sensitive to rising temperatures, but the direction of change depends on a complex interaction between temperature, predation risk, and predator thermal preference. Here, I developed an individual-based optimal foraging model of three trophic levels (primary producers, herbivores, and predators) to examine how warming affects top-down control of primary producers via both trait- and density-mediated indirect interactions (TMII and DMII). This model also factorially crossed warm- and cold-adapted herbivores and predators to determine how local adaptation modifies the effects of warming on food web interactions. Regardless of predator thermal preference, warming increased herbivore foraging effort and by extension predation rates. As a result, TMII declined in importance at high temperatures regardless of predator thermal adaptation. Finally, predation risk reduced herbivore fitness via both indirect (i.e., reduced herbivore size) and direct (i.e., reduced herbivore survival)...

Source: The American Naturalist - August 24, 2017 Category: Biology Authors: Lemoine NP Tags: Am Nat Source Type: research