Ontogenetic diet shifters profit competitively from predation
(English)Manuscript (preprint) (Other academic)
Integrating the simultaneous impacts of predation and resource competition on ecological communities is a major topic in community ecology. A number of studies have provided mechanisms that cause predation to affect competition between consumers for common resources especially in relation to resource productivity. We investigated how competition for two resources between two consumers of which one underwent an ontogenetic diet shift whereas the other was a generalist over its entire life time was affected by the presence of a predator feeding on both consumer populations. By assuming that consumers in the absence of ontogenetic niche shifts showed neutral coexistence, we were able to study the effects of ontogenetic niche shifts per se on competitive interactions. Predators differentially affected the resource requirements of diet shifters and generalist consumers and increased the region of resource supply where diet shifters competitively excluded generalists. Even in the case when generalists were superior competitors independent of resource supply, diet shifters could profit competitively from predators and even exclude the superior competitor when predators were present. Overall, diet shifters thus gained competitively from predation.
IdentifiersURN: urn:nbn:se:umu:diva-33416OAI: oai:DiVA.org:umu-33416DiVA: diva2:312022