of natural populations, community ecologists were often surprised by the large number of competing species that can be found in a relatively small area. Having in mind the Darwinian picture of natural selection and the survival of the fittest, one may expect that a few fittest species will dominate the community (perhaps with some sporadic presence of a few individuals of inferior species) as suggested by the competitive exclusion principle [@hardin1960competitive]. This is definitely not the case in many important communities, from tropical forests to coral reef to freshwater plankton. In fact, an understanding of the factors that allow the maintenance of biodiversity under selective dynamics is considered as one of the most important challenges for modern science [@science125].

One of the versions of the biodiversity puzzle has to do with a local community which is coupled by migration to a regional pool. The simplest example for this scenario is the mainland-island system, where the mainland dynamics is assumed to be relatively slow so one can assume that the island is interacting with (i.e., receiving immigration from) a static pool on the mainland. This mainland-island model may describe any local community, provided that the length scale involved in biological interactions 