%0 Journal Article %T Non-neutral theory of biodiversity %A Ginestra Bianconi %A Luca Ferretti %A Silvio Franz %J Quantitative Biology %D 2009 %I arXiv %R 10.1209/0295-5075/87/28001 %X We present a non-neutral stochastic model for the dynamics taking place in a meta-community ecosystems in presence of migration. The model provides a framework for describing the emergence of multiple ecological scenarios and behaves in two extreme limits either as the unified neutral theory of biodiversity or as the Bak-Sneppen model. Interestingly, the model shows a condensation phase transition where one species becomes the dominant one, the diversity in the ecosystems is strongly reduced and the ecosystem is non-stationary. This phase transition extend the principle of competitive exclusion to open ecosystems and might be relevant for the study of the impact of invasive species in native ecologies. %U http://arxiv.org/abs/0903.1753v2