Tuesday, August 3, 2010: 8:00 AM-11:30 AM
303-304, David L Lawrence Convention Center
A recent breakthrough in community ecology has come from the emergence of the metacommunity concept. A metacommunity is a regional set of local communities connected by dispersal of individuals. This concept holds that species coexistence, at both local and regional scales, is influenced by the interaction of two processes previously considered separately: dispersal among local communities, and competition within local communities. Through this synthesis, the theory and its empirical tests are yielding new insights into how communities are structured at multiple spatial scales.
However, two major weaknesses of metacommunity theory are that (1) they mostly focus on competitive interactions within a single trophic level, and that (2) they assume that species perceive the scale of habitat patchiness the same way. Although there is a large body of work on predator-prey interactions in space, most of these studies consider interactions between a few species instead of larger food webs. Closer attention has recently been paid to how individual movement across habitats affects multi-trophic dynamics. However, these studies have not been well integrated into the metacommunity concept. Spatial differences between trophic levels have been recognized, but poorly integrated into the metacommunity. In reality, species, particularly those belonging to different trophic levels, vary greatly in mobility and longevity, and therefore in how they perceive spatial scale.
The goal of this symposium is to synthesize our current understanding of trophic interactions and expand it to differing spatial scales toward a new multi-trophic metacommunity concept. This landscape-scale perspective enables us to ask a vast array of novel questions: How do we incorporate variation among trophic levels in the perception of scale into the metacommunity concept? How do we incorporate across-habitat resource subsidies to expand the metacommunity concept to ecosystems? How environmental heterogeneity and food web structure combine to affect species distribution? Will classical predictions for local food webs, such as those on the complexity-stability relationship or trophic cascades, hold in spatialized food webs? The symposium will bring together researchers with a range of expertise to tackle these questions. The program combines the presentation of new models of multi-trophic food webs in space and analysis of existing and new datasets, including experimental manipulations of metacommunity structure.