How many species in the United States warrant consideration for Endangered Species Act protection?

The U.S. Endangered Species Act ("ESA") currently protects 1,682 species as endangered or threatened. According to the independent scientific organization NatureServe, however, there are more than 10,000 imperiled species in the United States that may need protection. One barrier to protecting recognized imperiled species is a lack of threats information. To address this problem, we reviewed all species recognized as critically imperiled (G1) or imperiled (G2) by NatureServe to identify those facing documented threats. In total, we identified 2,204 species where there is sufficient threat information to indicate ESA protection may be warranted. This analysis indicates that more than double the species currently listed under the ESA may need protection to avoid extinction. The U.S. Fish and Wildlife Service ("Service") has on average listed just 32 species per year since the law was passed in 1973. At this rate, most species currently recognized as imperiled and facing threats will not receive consideration for protection within any meaningful timeframe.