Estimating species richness: still a long way off!

Xu etal., in this issue of the Journal of Vegetation Science, compare several species richness estimators. All the non-parametric estimators, such as Chao and jackknife estimators, underestimated the true number, whereas all the area-based models, based on speciesarea curves, overestimated it. No reliable method yet exists to predict the number of species in an area that is appreciably larger than the one(s) sampled.