We constructed a simulation model of metapopulation dynamics consisting of two or three habitat patches using STELLA. our simulations show that, given the assumptions of the deterministic model, the metapopulation is doomed to global extinction with or without interpatch immigration when all local populations are below minimum viable population (MVP) size. This suggests that for a cluster of scattered small populations, it is preferable to focus on augmenting individual population sizes rather than enhancing interpatch immigration. In the case when at least one of the subpopulations is above the MVP size, there is a critical size for that subpopulation above which the metapopulation persists and otherwise collapses. Also, when a metapopulation system is composed of more than two patches, the spatial configuration in terms of patch connection and the relative position of the above-MVP subpopulation will have significant effects on metapopulation dynamics and persitence. All simulation results from the three-patch animal metapopulation model suggest that both the number of interpatch connections and the magnitude represented by them are crucial for overall patch connectivity. The magnitude of interpatch immigration is positively related to the minimum size of the above-MVP subpopulation in both the two- and three-patch metapopulation systems due to population sink effect. The phenomenon is especially significant when subpopulations in sink patches are well below MVP. Appropriate introduction of stochastic components into the model may increase its realism especially for the cases where all subpopulations are well below MVP. Although the current version of the model involves no more than three patches, it may serve as a general conceptual framework and a specific simulator for modeling metapopulation dynamics incorporating a variety of spatial arrangements of habitat patches.
ASJC Scopus subject areas
- Ecological Modeling