The undeniable progression of climate change has had a multitude of deleterious effects on the structure and function of ecosystems. Rising temperatures cannot only spur the extinction and migration of species, but with it alter the structure of who-eats-whom in an ecosystem. In arctic food webs, where temperature increases are most dramatic, species are moving into warming waters and forming novel trophic connections with resident species concurrently; the extinction of species is spurring this same rewiring of food webs. We anticipate, however, that the rewiring of food webs should be preceded by detectable changes to parameters like mortality, attack and conversion efficiency rates in consumer-resource interactions owing to asymmetrical responses to temperature increases in these parameters. Here we used a Rosenzweig-MacArthur model with an ectothermic omnivore to explore how interaction strengths in food webs with omnivory shift with temperature warming.
Results/Conclusions
We found that temperature warming could induce the breakdown of omnivory into food chain, exploitative competition and polyphagy modules. As we increased the temperature, attack rates changed per temperature response curves concurrently changing the interaction strengths in the food web. At high temperatures, the omnivorous interaction was lost. This loss of omnivory and the stability it confers has the potential to render these ecosystems more susceptible to extinction as population variation is expected to increase without omnivory. We submit these food web analyses, which anticipate species loss, are a promising early warning indicator of ecosystem change.