Despite their ubiquity in nature, the manner by which omnivores affect the stability and functioning of their food webs remains poorly understood. Two approaches have predominated past investigations: mathematical modeling, and the observation of feeding relationships to qualitatively reconstruct food webs. These approaches have produced conflicting predictions regarding the importance of omnivory such that a mechanistic understanding of how omnivores affect their communities remains unrealized. Seminal conceptual models of ecology that relate the functioning of food webs to the productivity of their communities rely on strong assumptions about the role that omnivores play however. The research proposed here employs an observation-based approach to quantify the strength of species interactions in food webs of the New Zealand intertidal along a natural productivity gradient. This project will thus provide a much needed assessment of key predictions concerning the mechanisms by which omnivorous species affect their communities.
Aside from providing the much needed link between the theoretical and empirical realms of food web ecology that is necessary to inform conservation and resource-use practices, this research project will contribute greatly to our natural history knowledge of this understudied region of the world. In doing so, it will provide an informative contrast to the more extensively studied intertidal systems of other continents.
