Where are All the Species?: Using Higher-Taxon Richness to Predict Species Richness

Abstract

There is a large body of empirical studies that report significant relationships between the number of species and the number of higher taxa, making this a promising approach to estimate the numbers of species in locations in which higher taxa may be better known than the numbers of species. However, there is a lack of comparative studies to assess if 1) there is any commonality of this relationship across distinct taxonomic groups and if 2) such tendencies are scale-dependent, which might allow extrapolations to predict the numbers of species found globally. Here I assess these two questions for twelve taxonomic groups, in both marine and terrestrial environments and evaluate the efficacy of using higher taxa to predict species richness (i.e. the higher-taxon approach) from the local to global scales.