The Influences Of Allee-like Effects On Metapopulation Dynamics

Metapopulation is consisted of many local populations which distribute discretely in patches and have risks of extinction. In 1969, Levins put forward the concept of metapopulation to describe the population made up of unstable populations living in fragmented patches. Metapopulation can exist by the dynamical balances of the extinction of populations and the recolonization of empty patches.Till now, the significance of Allee effects in population dynamics has been gradually recognized. However, most researches focus on Allee effects at local population level, while research on Allee-like effects at metapopulation level still remains so limited. At metapopulation level, when the proportion of patches already occupied is below a certain value, the rate of increase in the rate of occupation will decrease with decreased proportion of patches occupied. And when it reaches a critical value, the rate of occupation will not increase any more and so the metapopulation will go extinct. Amarasekare called this biological phenomenon Allee-like effects(Amarasekare 1998). Studies show that if there is Allee effects at local population level, an Allee-like effects may arise at the metapopulation level(Zhou & Wang 2004). This paper concentrates on the influences of Allee-like effects on the dynamics of metapopulation, mainly using the method of numerical simulations to deal with the model of predation and the model of apparent competition. In the model of predator-prey on metapopulation level, Allee-like effects influence predators more intensively. In the model of apparent competition on metapopulation level, different forms of Allee-like effects may influence the system differently. All in all, Allee-like effects is an unstable factor for the ecological system.