How trophic interaction strength depends on traits: A conceptual framework for representing multidimensional trophic niche spaces

A key problem in community ecology is to understand how individuallevel traits give rise to population-level trophic interactions. Here we propose a synthetic framework based on ecological considerations to address this question systematically. We derive a general functional form for the dependence of trophic interaction coefficients on trophically relevant quantitative traits of consumers and resources. The derived expression encompasses—and thus allows a unified comparison of—several functional forms previously proposed in the literature. Furthermore, we show how a community’s, potentially low-dimensional, effective trophic niche space is related to its higher-dimensional phenotypic trait space. In this manner, we give ecological meaning to the notion of the “dimensionality of trophic niche space”. Our framework implies a method of directly measuring this dimensionality. We suggest a procedure for estimating the relevant parameters and verifying the assumptions underlying our derivation for