Empirical study of complex food webs in tropical forests using experiments
Local food webs in tropical forests may comprise as many as 100,000 distinct inter-specific trophic interactions. Unsurprisingly, none of the existing webs has been thoroughly documented. Here we review approaches to food web inventory and argue that manipulative experiments on food webs represent the most promising approach to their study. The manipulation, both insertion and exclusion, of resources and consumers offer opportunities to reveal the dynamics of food web assembly and resilience to changing environmental conditions and disturbance. We provide examples of such manipulations for plants, herbivores, parasitoids and predators in the forests of New Guinea and discuss the lessons learned, in particularly in the framework of the bottom-up versus top-down control of individual trophic levels, as well as the future directions of food web research.