A Stochastic Model for the Species Abundance Problem in an Ecological   Community
  We propose a model based on coupled multiplicative stochastic processes to understand the dynamics of competing species in an ecosystem. This process can be conveniently described by a Fokker-Planck equation. We provide an analytical expression for the marginalized stationary distribution. Our solution is found in excellent agreement with numerical simulations and compares rather well with observational data from tropical forests. 
Simone Pigolotti, Alessandro Flammini and Amos Maritan