title: Predator foraging behaviour drives food-web topological structure.
abstract: 1. The structure and dynamics of prey populations are shaped by the foraging behaviours of their predators. Yet, there is still little documentation on how distinct predator foraging types control biodiversity, food-web architecture and ecosystem functioning. 2. We experimentally compared the effects of model fish species of two major foraging types of lake planktivores: a size-selective visual feeder (bluegill), and a filter feeder (gizzard shad). The visual feeder forages on individually captured consumer prey, whereas the filter feeder forages on various prey simultaneously, not only consumers but also primary producers. We ran a 1-month mesocosm experiment cross-classifying a biomass gradient of each predator type. We analysed the effect of each fish on food-web architecture by computing major topological descriptors over time (connectance, link density, omnivory index, etc.). These descriptors were computed from 80 predator-prey binary matrices, using taxa mostly identified at the species level. 3. We found that the visual feeder induced more trophic cul-de-sac (inedible) primary-producer species, lower link density and connectance, and lower levels of food-web omnivory and generalism than the filter feeder. Yet, predator biomass did not affect food-web topology. 4. Our results highlight that top-predator foraging behaviour is a key functional trait that can drive food-web topology and ultimately ecosystem functioning.
authors.affiliation: UMR 7208 Borea, Centre National de la Recherche Scientifique, IRD, UPMC, MNHN, CP 53, Paris cedex 5, France. xavier.lazzaro@ird.fr
authors.forename: Xavier
authors.initials: X
authors.lastname: Lazzaro
authors.forename: Gérard
authors.initials: G
authors.lastname: Lacroix
authors.forename: Benoît
authors.initials: B
authors.lastname: Gauzens
authors.forename: Jacques
authors.initials: J
authors.lastname: Gignoux
authors.forename: Stéphane
authors.initials: S
authors.lastname: Legendre
mesh_terms: D000818:Animals; D044822:Biodiversity; D005399:Fishes / Q000502:physiology; D020387:Food Chain; D008954:Models, Biological; D011235:Predatory Behavior