### The neutral community model with random fission speciation

- Series
- Mathematical Biology Seminar
- Time
- Wednesday, October 14, 2009 - 11:00 for 1 hour (actually 50 minutes)
- Location
- Skiles 269
- Speaker
- Bart Haegeman – INRIA, Montpellier, France

Hubbell's neutral model provides a rich theoretical framework to study
ecological communities. By coupling ecological and evolutionary time
scales, it allows investigating how communities are shaped by speciation
processes. The speciation model in the basic neutral model is particularly
simple, describing speciation as a point mutation event in a birth of a
single individual. The stationary species abundance distribution of the
basic model, which can be solved exactly, fits empirical data of
distributions of species abundances surprisingly well. More realistic
speciation models have been proposed such as the random fission model in
which new species appear by splitting up existing species. However, no
analytical solution is available for these models, impeding quantitative
comparison with data. Here we present a self-consistent approximation
method for the neutral community model with random fission speciation. We
derive explicit formulas for the stationary species abundance
distribution, which agree very well with simulations. However, fitting the
model to tropical tree data sets, we find that it performs worse than the
original neutral model with point mutation speciation.