Consistent temperature dependence of functional response parameters and their use in predicting population abundance

Abstract

Global warming is one of the greatest threats to the persistence of populations: increased metabolic demands should strengthen pairwise species interactions, which could destabilize food webs at the higher organizational levels. Quantifying the temperature dependence of consumer–resource interactions is thus essential for predicting ecological responses to warming.We explored feeding interactions between different predator–prey pairs in controlled‐temperature chambers and in a system of naturally heated streams. We found consistent temperature dependence of attack rates across experimental settings, though the magnitude and activation energy of attack rate were specific to each predator, which varied in mobility and foraging mode.We used these parameters along with metabolic rate measurements to estimate energetic efficiency and population abundance with warming. Energetic efficiency accurately estimated field abundance of a mobile predator that struggled to meet its metabolic demands, but was a poor predictor for a sedentary predator that operated well below its energetic limits. Temperature effects on population abundance may thus be strongly dependent on whether organisms are regulated by their own energy intake or interspecific interactions.Given the widespread use of functional response parameters in ecological modelling, reconciling outcomes from laboratory and field studies increases the confidence and precision with which we can predict warming impacts on natural systems.

Foraging strategy mediates ectotherm predator–prey responses to climate warming

“…Therefore, our results may have been due to species‐specific differences in temperature responses rather than differences in foraging strategy. We believe that additional research will reveal that foraging strategy affects species’ responses to climate warming in predictable ways (e.g., Barton and Schmitz 2009, Archer et al 2019). At present, more research using multiple species of active and sit‐and‐wait predator is needed to validate our results and predictions of theory (Dell et al 2014).…”

Theory of temperature-dependent consumer-resource interactions

“…Currently, consumer survival has been inferred through energetic efficiencythe effective energetic gain of consumers at a certain resource density, which requires determining the thermal dependence of the functional response (Vucic-Pestic et al 2011;Archer et al 2019).…”

“…Following this comparison, we plotted four additional parameterisations from the literature onto the ρ − κ plane to broaden the comparative picture and demonstrate the simplicity of applying the framework to empirically-derived measurements. These consisted of two monotonic parameterisations (Vucic-Pestic et al 2011; Binzer et al 2016), one where only r was unimodal (Sentis et al 2012) and one which though monotonic, did include some distinctive thermal dependencies – increasing K ( t ) and e ( t ) and no thermal dependence of h (Archer et al 2019). We provide a description of the studies and details of their parameterisations in the supplementary material (SI 4).…”

Thermal mismatches in biological rates determine trophic control and biomass distribution under warming

“…Such mismatches in thermal curves of interacting species have been widely reported (Dell et al, 2011) and shown to strongly influence species interactions under warming (Archer et al, 2019;Betini et al, 2019;Bideault et al, 2019;Dell et al, 2014;Laws & Joern, 2013;Sentis, Binzer, et al, 2017). For instance, autotrophic and heterotrophic biological processes have been shown to exhibit different thermal sensitivities which can lead to increased grazing pressure and reduced primary producers standing biomass in aquatic systems (O'Connor et al, 2009).…”