title: The body size dependence of trophic cascades.
abstract: Trophic cascades are indirect positive effects of predators on resources via control of intermediate consumers. Larger-bodied predators appear to induce stronger trophic cascades (a greater rebound of resource density toward carrying capacity), but how this happens is unknown because we lack a clear depiction of how the strength of trophic cascades is determined. Using consumer resource models, we first show that the strength of a trophic cascade has an upper limit set by the interaction strength between the basal trophic group and its consumer and that this limit is approached as the interaction strength between the consumer and its predator increases. We then express the strength of a trophic cascade explicitly in terms of predator body size and use two independent parameter sets to calculate how the strength of a trophic cascade depends on predator size. Both parameter sets predict a positive effect of predator size on the strength of a trophic cascade, driven mostly by the body size dependence of the interaction strength between the first two trophic levels. Our results support previous empirical findings and suggest that the loss of larger predators will have greater consequences on trophic control and biomass structure in food webs than the loss of smaller predators.
authors: School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588.
authors: John P
authors: JP
authors: DeLong
authors: Benjamin
authors: B
authors: Gilbert
authors: Jonathan B
authors: JB
authors: Shurin
authors: Van M
authors: VM
authors: Savage
authors: Brandon T
authors: BT
authors: Barton
authors: Christopher F
authors: CF
authors: Clements
authors: Anthony I
authors: AI
authors: Dell
authors: Hamish S
authors: HS
authors: Greig
authors: Christopher D G
authors: CD
authors: Harley
authors: Pavel
authors: P
authors: Kratina
authors: Kevin S
authors: KS
authors: McCann
authors: Tyler D
authors: TD
authors: Tunney
authors: David A
authors: DA
authors: Vasseur
authors: Mary I
authors: MI
authors: O'Connor
mesh_terms: D000818:Animals; D049628:Body Size; D003247:Conservation of Natural Resources; D056890:Eukaryota; D020387:Food Chain; D008962:Models, Theoretical; D011235:Predatory Behavior / Q000502:physiology