Predation Risk Reverses the Potential Effects of Warming on Plant-Herbivore Interactions by Altering the Relative Strengths of Trait- and Density-Mediated Interactions
Authored by Nathan P Lemoine
Date Published: 2017
DOI: 10.1086/692605
Sponsors:
United States Department of Agriculture (USDA)
Platforms:
No platforms listed
Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
Model code not found
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) pathways. These results suggest that,
contrary to previous predictions, warming might stimulate primary
productivity by reducing herbivore population sizes, releasing plants
from immediate top-down control.
Tags
Individual-based model
ecology
indirect interactions
Consumption
Communities
Body-size
Prey interactions
Trophic cascades
Metabolic-rate
Temperature-dependence
Linking
Herbivore fitness
Primary production
Grassland food-chain