Stochastic effects on biodiversity in cyclic coevolutionary dynamics
  Finite-size fluctuations arising in the dynamics of competing populations may have dramatic influence on their fate. As an example, in this article, we investigate a model of three species which dominate each other in a cyclic manner. Although the deterministic approach predicts (neutrally) stable coexistence of all species, for any finite population size, the intrinsic stochasticity unavoidably causes the eventual extinction of two of them. 
Tobias Reichenbach, Mauro Mobilia, and Erwin Frey