濒危蝴蝶生活在军事基地

As a large explosion is heard in the distance, a St. Francis Satyr butterfly flies around, ready to lay as many as 100 eggs. At one point, this brown butterfly could be found in only one place: a military base in the American state of North Carolina.

An estimated 3,000 St. Francis Satyrs exist. The very small insects are one of the rarest butterfly species in the world.

The almost 50-year-old Endangered Species Act protects the St. Francis Satyr along with about 1,600 other American species. However, recent changes to the law have led some to worry that threatened species in the United States may be at increasing risk.

The endangered species act – successes and challenges

To some experts, the existence of these butterflies means the Endangered Species Act has done its job. More than 99.2% of the species protected by it survive, The Associated Press has found. In contrast, only 39 U.S. species — or about 2% of the overall number — have made it off the endangered list. These include well-known successes such as the bald eagle, peregrine falcon and the American alligator.

Jake Li is the director for biodiversity at the non-profit Environmental Policy Innovation Center in Washington, DC. He says the condition of many species on the endangered list is worsening. Only eight percent of species are improving, says an organization report.

Li said many species will remain on the list. "And I don't think that's a failure of the Endangered Species Act itself," he added.

Political disagreements

Lawmakers designed the law to prevent species from disappearing. President Richard Nixon signed the Endangered Species Act into law on Dec. 28, 1973. The measure led to many political conflicts in the 1970s and 1980s. One famous example is the fight over plans to build the Tellico Dam in Tennessee.

Now, the law is in dispute once again.

In September, the Trump administration changed the endangered species process. Opponents argue that the changes weaken the law.

Among them: a change in the rules for species that are "threatened," the classification just below endangered. Instead of saying that "threatened" species get the same protection as endangered species, the new rules include possible exceptions.

Gary Frazer, assistant director of ecological services at U.S. Fish and Wildlife, says the changes improve the situation. He said they permit the government to better protect "things that are important to conservation."

Michael Bean, a former Interior Department official, disagrees. He calls the plan a "step back," although not "catastrophic."

Noah Greenwald, with the non-profit Center for Biological Diversity, is more concerned. He calls the changes "a disaster."

The biggest problem, Li and others say, is that new species in trouble are not being added to the list.

Meanwhile, scientists across the globe warn of the coming extinction of a million species in the decades ahead.

St. Francis Satyr

Nick Haddad, a Michigan State University biology professor, is the world's leading expert on the St. Francis Satyr butterfly. He got permission to go to the animal's home on the military base.

The butterfly appears only twice a year for two weeks each time. When it does, Haddad goes to Fort Bragg and joins a team of Army biologists aiming to improve the butterflies' living environment.

Haddad and his students also walk through the swamp and count the insects.

"It couldn't be better than this," Haddad says, smiling as a butterfly takes flight. "When I see, every year, just a slight change in the right direction of the butterfly's conservation, let me tell you, that inspires me."

I'm John Russell.

And I'm Alice Bryant.

Seth Borenstein reported on this story for the Associated Press. John Russell adapted it for Learning English. Caty Weaver was the editor.