Big angiosperm genera are priorities for conservation

Species in big angiosperm genera (≥500 species) tend to be less well-known than those in smaller genera. Consequently, species in big genera are underrepresented in conservation at all levels, from analyses to actions. However, emerging evidence indicates that species in larger genera tend to have smaller geographic ranges (a strong correlate of increased extinction risk). Here, we test the global generality of this pattern, and the relationships between plant taxon size, extinction risk and climatic zone on a global scale. Species in larger genera are more likely to have small ranges, less likely to have a global Red List assessment, but are more likely to be threatened. Persistent obstacles to improving conservation documentation of big genera include taxonomic uncertainty, data shortfalls and number of species involved. We highlight the need for closer collaboration between taxonomy and conservation to enable effective conservation of the quarter of plant species that big genera encompass.