The sensitivity of complex dynamic food webs to the loss of top omnivores

Abstract

Theoretical studies have attempted to predict the effects of losing species and their relative importance to community-level processes, but little attention has been paid to specific interaction types such as omnivory and the trophic level of extinct species. Here, we use complex food web models to assess the importance of omnivores to community-level stability. We simulated food webs with varying size and complexity so we could remove omnivores from different trophic levels and track the fates of communities. Results show that food webs were more sensitive to the loss of omnivores from higher trophic levels, aside from the effects of network size and complexity on food web stability. These results underline the importance of omnivory by introducing dynamic switching across multiple energy paths. We expect this paper to shed light on additional factors that are fundamental when modelling extinctions such as the trophic level of lost species.