Species Abundances Distribution in Neutral Community Models
  An analytical approximation is derived for the Zero Sum Multinomial distribution which gives the Species Abundance Distribution in Neutral Community Models. The obtained distribution function describes well computer simulation results on the model, and leads to an interesting relation between the total number of individuals, total number of species and the size of the most abundant species of the considered metacommunity. Computer simulations on neutral community models, proves also the validity of this scaling relation. 
Z. Neda and M. Ravasz