Unifying environmental and spatial determinants of food web structure across spatial scales

Abstract

Species affect on each other in complex ways, and ecological networks - such as food webs - describe how interactions connect species. Although ecological network theory has allowed predictions of how perturbations ricochet between species, it remains limited in several key respects. First, ecological networks are often only considered at small spatial scales, even though metacommunity theory has demonstrated that longer-distance events (like dispersal) or larger-scale patterns (like climatic of biogeographic gradients) can have large impacts on local ecological dynamics. Second, there is accumulating evidence that the traits of species provide the mechanistic basis for species interactions, but most traits have not yet been incorporated into network analyses. Here we propose to integrate network, metacommunity and trait-based analyses of food webs to determine: (1) how and why does food web structure changes over space, (2) which traits of species are most important in determining their trophic interactions, and (3) if species traits determine shifts in food web structure over environmental gradients. We will address these questions using the aquatic food webs in tank bromeliads across the entire range of this system, from Mexico to Argentina and through the Caribbean. The current database is comprised of 1762 tank bromeliads and their associated macrofauna at 22 locations distributed in 10 countries. This project aims to combine these existing species, trait and environmental data with new site-specific interaction matrices to generate potential food webs. We anticipate that the integrated and multiscale approach of this project will be crucial providing novel perspectives on the ecology of complex systems. (AU)