Kevin McCann, Professor, Department of Integrative Biology, University of Guelph 

Climate change is differentially altering environmental conditions from local to global scales, creating novel heterogeneity in space. Here, we argue that this novel heterogeneity will drive mobile generalist species, which navigate between habitats and ecosystems, to rapidly respond through their behavior, presenting a powerful and underutilized theoretical and empirical approach to understand and predict climate change impacts on ecosystems. We use existing data and theory to show that these rapid behavioral responses by generalists will broadly and predictably reorganize (i.e., rewire) food webs in two critical ways: (i) redistribution (e.g., poleward, upslope) of mobile generalist species capable of foraging on novel prey will cause the addition and loss of species and connections (topological rewiring), and; (ii) generalist foragers will behaviorally respond to altered habitat and ecosystem conditions in ways that alter pathways of energy and carbon transfer through the food web (interaction strength rewiring). We end by arguing that these generalists can act as sentinel species in that their rapid behavioral responses can serve as much-needed early warning signals for monitoring the looming impacts of global climate change on whole ecosystems.