Bad for Species, Bad for People: What’s Wrong with the Endangered Species Act and How to Fix It

Studies | Environment

No. 303
Saturday, September 01, 2007
by Brian Seasholes


Does the Endangered Species Act Save Species?

When confronted with the embarrassing reality that the ESA is harmful to species, the Act's proponents fall back on two arguments they claim prove otherwise.

First, they contend that although some species that were listed are now extinct, far more would have perished without the ESA.  One study claimed that but for the Act, 192 listed species now would be extinct, rather than the seven that had been delisted due to extinction at the time of the study's publication. 25 However, this assertion is fundamentally flawed.  It applies a very rough (and likely inappropriate) estimate of extinction rates for all species to those listed under the ESA.  Despite this, ESA advocates have cited the study as evidence the Act works. 26

“Flawed data are used to determine the status of species.”

The more widespread variant of the extinction prevention argument is that almost all species listed under the ESA are not extinct.  “[T]he law is a profound success,” claims the National Audubon Society.  “According to the U.S. Fish and Wildlife Service, the ESA has prevented extinction for 99 percent of the species that are listed as endangered or threatened.” 27 This claim is unsupportable.  Due to the fact that imperiled species are by definition the most susceptible to extinction, statistically, some would have perished with or without the ESA's intervention. There is no valid data to support the claim that the ESA has stemmed the tide of extinction for listed species, much less that the Act is responsible for the continued existence of 99 percent of the listed species. 28

“Official reasons for delisting are inaccurate.”

Second, ESA proponents claim that the Act is responsible for the Service's characterization of the majority of listed species as “stable” or “improving.”   The National Wildlife Federation claims that of the listed species whose status is known, 68 percent are stable or improving.  The Federation also says, “The longer a species enjoys the Endangered Species Act's protections, the more likely it is that its condition will stabilize or improve.” 29

However, these claims cannot be substantiated because they are based on invalid data.  Every two years the Service sends out a questionnaire to the field biologists responsible for various species, asking them to categorize their species as improving, declining, stable or unknown. 30 But the results are flawed in two basic ways.  First, the data are not collected using any sort of standardized methodology that is replicable or that yields meaningful results.  Second, data are not collected every year for all species.  Others have also noticed that these data are not valid, such as:  David Wilcove, formerly with Environmental Defense and currently a professor at Princeton University; the National Research Council's report on the ESA; and Charles Mann and Mark Plummer, authors of a book and several articles on the Act. 31 [See the sidebar on flawed data.]


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