The Role Of Fish Life Histories In Allometrically Scaled Food-Web Dynamics

Abstract

Body size determines key ecological and evolutionary processes of organisms. Therefore, organisms undergo extensive shifts in resources, competitors and predators as they grow in body size. While empirical and theoretical evidence show that these size-dependent ontogenetic shifts vastly influence the structure and dynamics of populations, theory on how those ontogenetic shifts affect the structure and dynamics of ecological networks is still virtually absent. Here, we take a first step towards generating such theory by developing an Allometric Trophic Network (ATN) model that incorporates size-structure in the population dynamics of fish species within complex food webs. Our preliminary results show that fish with larger allometric ratios attain higher biomass and tend to be correlated with greater ecosystem stability. We also find that that fish with a larger asymptotic body mass tend to be correlated with a larger total ecosystem biomass, a result that holds true across models for both the largest fish in the ecosystem and each fish species in the ecosystem. The approach adopted here offers a potentially instructive means of disentangling the effects of increasing life-history complexity in food-wed models.