Abstract
Species richness is an essential biodiversity variable indicative of ecosystem states and mass extinctions both contemporarily and in fossil records. However, limitations to sampling effort and spatial aggregation of organisms mean that surveys often fail to observe some species, making it difficult to estimate true richness and hinder the comparison of communities. Here we present a nonparametric, asymptotic, minimal-bias richness estimator, Ωo, by modelling how spatial abundance characteristics affect observation of species richness. Ωo consistently outperforms the best-established richness estimators and can detect small differences that other methods cannot. We conducted simulation tests and applied Ωo to a seaweed survey dataset. Ωo returns more consistent estimates and bootstrapped confidence bounds across years and approaches asymptote with less data than other estimators. The results provide theoretical insights on how biotic and observer variations affect species observation, identify remaining problems, and quantify possible performance gains based on Ωo.
Competing Interest Statement
The authors have declared no competing interest.