PARENT SESSION
Organized Oral Session 49: Scaling species abundance, distribution and diversity: From pattern to process
Organizer(s): WE Kunin and H Lewis
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 511a, Level 5, Palais des congrès de Montréal
Spatial models of food webs.
Banasek-Richter, Carolin*,1, Otto, Sonja1, Brose, Ulrich1, 1 Darmstadt University of Technology, Darmstadt, Germany
ABSTRACT- Different ecological scaling theories predict how community properties vary with habitat area (spatial scaling) or species richness (trophic scaling). Most importantly, spatial scaling describes how the species richness of a community changes with habitat area, whereas trophic scaling refers to changes in food web properties with species richness. In the past, conventional food web properties have been found to depend on scale (i.e. they vary with species richness). Less extensively explored is the question if other features of a community can also serve to determine or regulate food web structure. Ecosystem size has been proposed as being such a feature. This idea triggered the formulation of the unified scaling model which forecasts changes of a specific food web property (the number of trophic links) with species richness and habitat area. On the basis of empirical food web data from streams, lakes, and ancient woodland plots we explore the question if habitat area has a direct effect on food web structure, or if spatial effects are always mediated by species richness. Our results indicate that the latter assumption is more likely, as habitat area influences species richness, which in turn determines food web structure. Based on the unified scaling model and knowledge of habitat area we furthermore investigate how much empirical information about the number of trophic interactions or species richness is required for models of food webs to make feasible predictions of food web structure. The trophic models employed for this analysis are the nested-hierarchy and the niche model.
Key words: spatial scaling, food web structure, unified scaling model