title: Effect of introducing a competitor on cyclic dominance of sockeye salmon.
abstract: We study the effects of introducing a competing species into a 3-species model for the population dynamics of sockeye salmon, thereby converting a food chain into a diamond module. We find that this often leads to the disappearance of the 4-year oscillation of sockeye salmon known as cyclic dominance when parameters are chosen such that all four species can coexist. Only when the population size of the competitor is small the phenomenon of cyclic dominance can persist. There is also a large region of parameter space where either the sockeye salmon or the competitor goes extinct. We discuss how these findings can be reconciled with the prevalence of cyclic dominance in many sockeye brood lakes.
authors: Institut für Festkörperphysik, TU Darmstadt, Hochschulstraße 6, 64289 Darmstadt, Germany. Electronic address: christophschmitt@fkp.tu-darmstadt.de.
authors: Christoph K
authors: CK
authors: Schmitt
authors: Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands. Electronic address: c.p.guill@uva.nl.
authors: Christian
authors: C
authors: Guill
authors: Fisheries and Oceans Canada, 9860 West Saanich Road, Sidney B.C., Canada V8L 4B2. Electronic address: eddy.carmack@dfo-mpo.gc.ca.
authors: Eddy
authors: E
authors: Carmack
authors: Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94248, 1090 GE Amsterdam, The Netherlands. Electronic address: drossel@fkp.tu-darmstadt.de.
authors: Barbara
authors: B
authors: Drossel
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D003163:Competitive Behavior / Q000502:physiology*; D003198:Computer Simulation; D020387:Food Chain; D008954:Models, Biological; D011157:Population Dynamics; D012474:Salmon / Q000502:physiology*; D013045:Species Specificity
keywords: Apparent competition; Diamond motif; Food chain; Oncorhynchus nerka; Single generation cycle