Spatial dynamics of specialist seed predators on synchronized and intermittent seed production of host plants.
Masting, the synchronized and intermittent seed production by plant populations, provides highly variable food resources for specialist seed predators. Such a reproductive mode helps minimize seed losses through predator satiation and extinction of seed predator populations. The seed predators can buffer the resource variation through dispersal or extended diapause. We developed a spatially explicit resource-consumer model to understand the effect of masting on specialist seed predators. The masting dynamics were assumed to follow a resource-based model for plant reproduction, and the population dynamics of the predator were represented by a spatially extended Nicholson-Bailey model. The resultant model demonstrated that when host plants reproduce intermittently, seed predator populations go locally extinct, but global persistence of the predator is facilitated by dispersal or extended diapause. Global extinction of the predator resulted when the intermittent reproduction is highly synchronized among plants. An approximate invasion criterion for the predators showed that negative lag-1 autocorrelation in seeding reduces invasibility, and positive lag-1 cross-correlation enhances invasibility. Spatial synchronization in seeding at local scale caused by pollen coupling (or climate forcing) further prevented invasion of the predators. If the predators employed extended diapause, extremely high temporal variability in reproduction was required for plants to evade the predators.
Satake
Akiko
A
Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan. satake@bio-math10.biology.kyushu-u.ac.jp
Bjørnstad
Ottar N
ON
D000818:Animals; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D007313:Insecta / Q000502:physiology*; D008954:Models, Biological; D011058:Pollen; D011157:Population Dynamics; D012639:Seeds / Q000502:physiology*; D013997:Time Factors; D014197:Trees / Q000502:physiology*