Fig. 2.

Categories of the 2,764 vertebrate species used in this study. (A) The number and relative proportion of the species in each taxon category. (B) IUCN Red List categories of the examined species and their relative proportions. CR, critically endangered; DD, data deficient; EN, endangered; LC, least concern; NE, not evaluated; NT, near threatened; VU, vulnerable. The threatened species include the species of critically endangered, endangered, and vulnerable, and the nonthreatened species include the near-threatened and least-concern species.