ABSTRACT

Here, we show that body-size and metabolism form a simple framework for understanding the general architecture of food webs on the landscape. We then examine the predictions that emerge from this framework and find that they are consistent with empirical data drawn from a number of different ecosystems. Specifically, food webs are large comprehensive entities whereby localized resources habitats are progressively coupled by more mobile higher order predators or consumers capable of rapid behavioral responses to complex spatial patterns. With this gross food web structure in mind we review food web theory. We argue that large mobile organisms promote the balance and maintenance of a diverse and variable assemblage of organisms, while the diverse lower level organisms, in turn, form a complex system of species capable of responding and buffering against an ever changing world. In this sense, the landscape architecture discussed here implies that nature is an intriguing balance of both bottom-up (habitat heterogeneity) and top-down (predator) forces. We end by briefly reviewing current human influences which suggest that human modifications tend to homogenize resources and remove higher order couplers and so seriously threaten the non-equilibrium balancing act of complex food webs.