Spatially realistic plant metapopulation models and the colonization-competition trade-off

1 Results from patch-occupancy metapopulation models indicate that a trade-off between competitive and colonization abilities is necessary for species to coexist in patchy environments. However, such models are often based on unrealistic ecological assumptions, such as global dispersal and no local population dynamics. 2 We develop a plant metapopulation model that allows us to sequentially relax unrealistic assumptions about dispersal and local population interactions. We use our model to examine the extent to which the conclusions of analytical, patch-based coexistence models depend on their assumptions. 3 We found that the need for an inferior competitor to be a superior colonizer was reduced by using a dispersal kernel to distribute seeds, and totally removed by relaxing the assumption of instantaneous competitive displacement. These results hold for annual or perennial plants with or without seedbanks, for global, local and stratified dispersal, for delayed competitive exclusion, two-way competition and neighbourhood competition, and for landscapes where habitat patches are either adjacent or disjunct. 4 We conclude that the results of patch-occupancy metapopulation models differ greatly from results of models that incorporate more realistic assumptions about dispersal and local population dynamics. As a result it may be premature to base biodiversity management and policy on the results of patch-occupancy models.