Resource dynamics influence the strength of non-consumptive predator effects on prey.
Predators influence prey populations both by consuming individual prey, and by inducing changes in prey behaviour that limit reproduction and survival. Because prey trade-off predation risk for foraging gains, the magnitude of predators' non-consumptive effects should depend on resource availability. Studies of non-consumptive effects generally adopt either of two strategies: (i) maintaining a static ration of the prey's resources; and (ii) using resource populations that vary dynamically in response to prey behaviour. Contrasting these experimental designs using meta-analysis, we evaluated whether resource dynamics influence the magnitude of non-consumptive effects on prey growth, survival, fecundity, population density, foraging rate and habitat use. Predators had a more negative effect on prey demography in dynamic- vs. static-resource experiments. Our results highlight the importance of resource dynamics in mediating the magnitude of non-consumptive effects of predators on prey, and illustrate the often-unintended impacts of experimental design on estimates of effect size in ecological interactions.
Preisser
Evan L
EL
Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA. preisser@uri.edu
Bolnick
Daniel I
DI
Grabowski
Jonathan H
JH
D000818:Animals; D020387:Food Chain; D016018:Least-Squares Analysis; D008954:Models, Biological; D011157:Population Dynamics; D011235:Predatory Behavior / Q000502:physiology*