4.3 - Body size, interaction strength, and food web dynamics

Abstract

This chapter describes some community-wide patterns obtained from real ecosystems where body size, abundance, and food web structure are known. The use of allometric relationships for predicting the strength of trophic interactions has been reviewed; these estimations can be used to investigate the dynamics of complex real systems. It is possible to find stable parameterizations of these dynamical systems by using observations of predator and prey body size and abundance. The connection between allometric relationships and the strength of species interactions is also examined and show that there is an analytical relationship between predator–prey body size ratio and interaction strength. There is a theoretical relationship between the body size ratio of a predator and its prey, and the per capita interaction strength between them. These interactions can be estimated by observing empirical patterns in real systems and indicate that metabolic scaling may underlie the stability of whole communities and ecosystems. This chapter provides a heuristic insight into the mechanisms that might produce the empirical patterns evident in such food webs.