From Food Webs to Ecological Networks: Linking Non-Linear Trophic Interactions with Nutrient Competition

This chapter presents an approach to explore the interplay of complex trophic interactions and consumption of multiple abiotic resources among producer species, using nonlinear and nonequilibrium numerical simulations. This approach transforms simple food-web models into more general models of complex ecological networks and can be scaled up to systems with many more species and abiotic resources. Food webs traditionally specify the structure of who eats whom among species within a habitat or ecosystem. A yet-to-be realized ideal is a food web model that includes the quantity consumed and the ecological relevance of every trophic interaction among all species within a community. The exclusive focus on feeding relationships or "trophic interactions" enables models of complex food webs to also incorporate exploitative and "apparent" competition among heterotrophs. However, this focus ignores similar interactions among autotroph producers or "basal species" consuming abiotic resources, along with other "nontrophic" interactions such as many forms of facilitation and competition. Explicit models of shared nutrient consumption including competition among producers for multiple resources are largely separate from trophic ecology.