The U.S. Endangered Species List is Missing Hundreds of Animals

The Endangered Species Act was landmark legislation for conservation when it was enacted in 1973. Since then it’s been a rather contentious bit of law, but its provisions—classifying species by amount of extinction risk, and enacting corresponding regulations—have prevented scores of extinctions.

But the effectiveness of the law is directly correlated to how well its implemented, which apparently isn’t very well. New research from the University of Adelaide suggests that a huge number of species near extinction haven’t made it onto the United States’ official ESA list. That means those species at the risk of extinction may disappear without receiving the benefits of legislation already on the books.

The study, published in Conservation Letters, compared the official ESA list to the International Union for the Conservation of Nature Red List, considered more or less the master list for all endangered and threatened species worldwide. The review found that, of American species, 40 percent of birds, 50 percent of mammals and a stunning 80-95 percent of less-glamorous groups (like amphibians, insects, and crustaceans) that are on the IUCN list don’t show up on the ESA list.

“The ESA has protected species since its establishment in 1973, and it may have prevented 227 extinctions. However, the implementation of the ESA by successive US governments has been problematic, including poor coverage of imperilled species, inadequate funding, and political intervention,” study leader Bert Harris, an Alabama native doing his PhD work in Adelaide, said. "Vague definitions of ‘endangered’ and ‘threatened’ and the existence of a ‘warranted but precluded’ category on the ESA list are also contributing to the gap in species classification."

That means 531 American species that are internationally recognized as being at risk aren’t considered threatened at home, meaning they aren’t afforded the legal support that can help save them. The missing species include popular bird species like the critically endangered Kittlitz’s murrelet, the endangered ashy storm-petrel, and the vulnerable cerulean warbler (pictured above). Harris attributed the difference partly to the fact that the meanings of classifications like ‘endangered’ and ‘threatened’ are often contested.

“The ESA is a powerful environmental law but its impact is limited. With many species being overlooked, this does not bode well for the ESA’s ability to mitigate species decline before they become critically imperiled. The IUCN Red List is imperfect, but it is the leading global threatened species list. It involves collaboration of many scientists, and regular refinement of its categories and criteria,” Harris said.

As mentioned, declaring a species endangered tends to incite a heap of spirited discussion, and the study doesn’t suggest that every choice on the IUCN Red List is correct. This is the first study directly comparing the two lists, and while it’s doubtful that either is totally perfect, the vast difference between the ESA list and the IUCN Red List suggests that there are indeed a number of species being incorrectly ignored by the ESA.

Lead photo via.