Bayesian estimation of Gini-Simpson’s index under mainland-island community structure

Abstract

The mainland-island community structure is an ecological transposition of a popular model in population genetics in which a fixed number of subpopulations (islands) are connected, through differing immigration rates, to a single metapopulation (mainland) where diversity is generated through speciation. It has been recently shown that a large class of neutral models with this particular structure converges in the large population limit to the Hierarchical Dirichlet process. This finding provides the analogous, in the multipopulation setting, of the Ewens sampling formula for the single population neutral hypothesis. Here we apply some recent results for conditional moments of diversity measures under Gibbs-type priors to derive a Bayesian nonparametric estimator of Gini-Simpson’s index under the Hubbell Unified Neutral Theory of Biodiversity and Biogeography. Potential applications are also illustrated.