title: Understanding how biodiversity unfolds through time under neutral theory.
abstract: Theoretical predictions for biodiversity patterns are typically derived under the assumption that ecological systems have reached a dynamic equilibrium. Yet, there is increasing evidence that various aspects of ecological systems, including (but not limited to) species richness, are not at equilibrium. Here, we use simulations to analyse how biodiversity patterns unfold through time. In particular, we focus on the relative time required for various biodiversity patterns (macroecological or phylogenetic) to reach equilibrium. We simulate spatially explicit metacommunities according to the Neutral Theory of Biodiversity (NTB) under three modes of speciation, which differ in how evenly a parent species is split between its two daughter species. We find that species richness stabilizes first, followed by species area relationships (SAR) and finally species abundance distributions (SAD). The difference in timing of equilibrium between these different macroecological patterns is the largest when the split of individuals between sibling species at speciation is the most uneven. Phylogenetic patterns of biodiversity take even longer to stabilize (tens to hundreds of times longer than species richness) so that equilibrium predictions from neutral theory for these patterns are unlikely to be relevant. Our results suggest that it may be unwise to assume that biodiversity patterns are at equilibrium and provide a first step in studying how these patterns unfold through time.
authors.affiliation: Institute of Biology, Ecole Normale Supérieure, 46 rue d'Ulm, Paris 75005, France missa@biologie.ens.fr.
authors.forename: Olivier
authors.identifier: http://orcid.org/0000-0002-4330-5192
authors.initials: O
authors.lastname: Missa
authors.affiliation: Biology Department, University of York, Wentworth Way, York YO10 5DD, UK.
authors.forename: Calvin
authors.identifier: http://orcid.org/0000-0002-4111-9484
authors.initials: C
authors.lastname: Dytham
authors.affiliation: Institute of Biology, Ecole Normale Supérieure, 46 rue d'Ulm, Paris 75005, France.
authors.forename: Hélène
authors.identifier: http://orcid.org/0000-0002-3195-7521
authors.initials: H
authors.lastname: Morlon
mesh_terms: D063147:Animal Distribution; D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D003198:Computer Simulation; D049810:Genetic Speciation; D008954:Models, Biological; D013997:Time Factors
keywords: Neutral Theory of Biodiversity; dynamic equilibrium; phylogenetic pattern; species abundance distribution; species area relationship; temporal predictions