Can cat predation help competitors coexist in seabird communities?

JOURNAL OF THEORETICAL BIOLOGY

卷:262

Article

Pontier, Dominique^1,2  Fouchet, David^1,2  Bried, Joel³ 

[1] Univ Lyon 1, CNRS, UMR5558, Lab Biometrie & Biol Evolut, F-69622 Villeurbanne, France

[2] Univ Lyon, F-69000 Lyon, France

[3] Univ Acores, Ctr IMAR, Dept Oceanog & Pescas, P-9901862 Horta, Acores, Portugal

关键词: Oceanic islands;    Seabirds;    Feral cats;    Nest site availability;    Date of arrival;    Community structure;    Predator-prey relationships;    Model;   

DOI  :  10.1016/j.jtbi.2009.09.006

来源: Elsevier

【 摘 要 】

On oceanic islands. nest site availability can be an important factor regulating seabird population dynamics. The potential for birds to secure a nest to reproduce can be an important component of their life histories. The dates at which different seabird species arrive at colonies to breed will have important consequences for their relative chances of success. Early arrival on the island allows birds to obtain nests more easily and have higher reproductive success. However, the presence of an introduced predator may reverse this situation. For instance, in the sub-Antarctic Kerguelen archipelago, early arriving birds suffer heavy predation from introduced cats. Cats progressively switch from seabirds to rabbits, since the local rabbit population starts to peak after early arriving seabird species have already returned to the colony. When late-arriving birds arrive, cat predation pressure on seabirds is thus weaker. In this paper, we investigate the assumption that the advantage of early nest mnopolization conferred to early arriving birds may be counterbalanced by the cost resulting from predation. We develop a mathematical model representing a simplified situation in which two insular seabird species differ only in their arrival date at the colony site and compete for nesting sites. We conclude that predation may ensure the coexistence of the two bird species or favor the late-arriving species, but only when seasonal variations in predation pressure are large. Interestingly, we conclude that arriving early is only favorable until a given level where high reproductive success no longer compensates for the long exposure to strong predation pressure. Our work suggests that predation can help to maintain the balance between species of different phenologies. (C) 2009 Published by Elsevier Ltd.

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