Rasmussen's recent work has concentrated on further large-scale collaborations with the same group of institutions studying global patterns in biodiversity. A survey of species richness and geographical range size did not show the decrease in range size from temperate regions to the tropics that had been previously assumed; although that pattern was largely true in the northern hemisphere, it did not appear to apply in the southern hemisphere. Research evaluating the relationship between extinction and human impact showed that, after controlling for species richness, the best predictors of the global pattern of extinction risk are measures of human impact, with ecological factors being of secondary importance. An examination of the distribution of rare and threatened vertebrate species, showed differing patterns for bird, mammal and amphibian species, which has consequences for hotspot-based conservation strategies.