A bioenergetic framework for the temperature dependence of trophic interactions

Abstract

Changing temperature can substantially shift ecological communities by altering the strength and stability of trophic interactions. Because many ecological rates are constrained by temperature, new approaches are required to understand how simultaneous changes in multiple rates alter the relative performance of species and their trophic interactions. We develop an energetic approach to identify the relationship between biomass fluxes and standing biomass across trophic levels. Our approach links ecological rates and trophic dynamics to measure temperature-dependent changes to the strength of trophic interactions and determine how these changes alter food web stability. It accomplishes this by using biomass as a common energetic currency and isolating three temperature-dependent processes that are common to all consumer-resource interactions: biomass accumulation of the resource, resource consumption and consumer mortality. Using this framework, we clarify when and how temperature alters consumer to resource biomass ratios, equilibrium resilience, consumer variability, extinction risk and transient vs. equilibrium dynamics. Finally, we characterise key asymmetries in species responses to temperature that produce these distinct dynamic behaviours and identify when they are likely to emerge. Overall, our framework provides a mechanistic and more unified understanding of the temperature dependence of trophic dynamics in terms of ecological rates, biomass ratios and stability.

The effects of temperature on aerobic metabolism: towards a mechanistic understanding of the responses of ectotherms to a changing environment

“…see Kordas et al, 2011;Amarasekare and Savage, 2012;Dell et al, 2014;Gilbert et al, 2014). Developing these empirically based models into true causeand-effect mechanistic models (Helmuth et al, 2005) will require insight into the proximate and ultimate causes of variation in the shape of TPCs.…”

Effects of acute and chronic temperature changes on the functional responses of the dogfish Scyliorhinus canicula (Linnaeus, 1758) towards amphipod prey Echinogammarus marinus (Leach, 1815)

“…The apparent species specificity of thermal dynamics poses an additional layer of difficulty in response prediction due to the metabolism of different species having varying sensitivity to temperature effects and therefore producing differential responses (Lang et al 2012). It is thus difficult to derive accurate conclusions from thermal responses modeled across numerous systems (Grigaltchik et al 2012), but it is widely agreed that temperature change alters ecological stability (Dell et al 2014;Gilbert et al 2014).…”

The temperature independence of interaction strength in a sit‐and‐wait predator

“…Interaction strengths are defined and measured in a variety of ways, from the relative effect of a consumer on the resource population abundance to parameters of the functional response (Wootton and Emmerson 2005, Novak and Wootton 2010, Gilbert et al 2014. Although these different interaction strength metrics integrate different sets of the components that make up a consumer-resource interaction, they all strive to quantify just how important the interaction is to the flux of energy and materials through a particular link in a food web.…”

“…Because of this, anything that influences interaction strengths can potentially influence food webs, and it has therefore become important to assess how various abiotic and biotic factors alter interaction strengths. In particular, expectations of increased mean environmental temperature associated with climate change has driven a growing interest in how temperature influences interaction strengths (O'Connor 2009, Gilbert et al 2014). …”