title: Species abundances and lifetimes: from neutral to niche-stabilized communities.
abstract: We study a stochastic community model able to interpolate from a neutral regime to a niche partitioned regime upon varying a single parameter tuning the intensity of niche stabilization, namely the difference between intraspecific and interspecific competition. By means of a self-consistent approach, we obtain an analytical expression for the species abundance distribution, in excellent agreement with stochastic simulations of the model. In the neutral limit, the Fisher log-series is recovered, while upon increasing the stabilization strength the species abundance distribution develops a maximum for species at intermediate abundances, corresponding to the emergence of a carrying capacity. Numerical studies of species extinction-time distribution show that niche-stabilization strongly affects also the dynamical properties of the system by increasing the average species lifetimes, while suppressing their fluctuations. The results are discussed in view of the niche-neutral debate and of their potential relevance to field data.
authors.affiliation: Dept. de Fisica i Eng. Nuclear, Universitat Politecnica de Catalunya Edif. GAIA, Rambla Sant Nebridi 22, 08222 Terrassa, Barcelona, Spain. Electronic address: simone.pigolotti@gmail.com.
authors.forename: Simone
authors.initials: S
authors.lastname: Pigolotti
authors.forename: Massimo
authors.initials: M
authors.lastname: Cencini
mesh_terms: D000818:Animals; D044822:Biodiversity; D003163:Competitive Behavior / Q000502:physiology; D017753:Ecosystem; D053476:Extinction, Biological; D008954:Models, Biological; D011156:Population Density; D011157:Population Dynamics; D013045:Species Specificity; D013269:Stochastic Processes
keywords: Neutral theory; Niche stabilization; Niche theory; Species abundance distribution; Species lifetimes