  Patterns of biodiversity predicted by the neutral theory rely on a simple
phenomenological model of speciation. To further investigate the effect of
speciation on neutral biodiversity, we analyze a spatially-explicit neutral
model based on population genetics. We define the metacommunity as a system of
populations exchanging migrants and we use this framework to introduce
speciation with little or no gene flow (allopatric and parapatric speciation).
We find that with realistic mutation rates, our metacommunity model driven by
neutral processes cannot support more than a few species. Adding natural
selection in the population genetics of speciation increases the number of
species in the metacommunity but the level of diversity found in Barro Colorado
Island is difficult to reach.
