The nene, Hawaii’s state bird, is no longer listed as endangered, but remains a point of concern for environmentalists wary of changes to the U.S. Endangered Species Act.

On Sunday, U.S. Secretary of the Interior David Bernhardt announced the downlisting of the Hawaiian goose — from endangered to threatened — at Pearl Harbor National Wildlife Refuge, signifying the species is a step closer to recovery.

That milestone, the U.S. Department of the Interior noted, comes after 60 years of collaborative conservation efforts among federal, state, local and nonprofit partners.

Among them, officials said, are an intensive captive breeding program, habitat restoration and active management strategies that have increased the nene population. As a result, the U.S. Fish and Wildlife Service finalized a 2018 proposal to move the nene from endangered to threatened.

“Today’s announcement highlights the progress the Endangered Species Act intends to deliver,” said Bernhardt in a news release Sunday. “Through collaboration and hard work the nene is out of intensive care and on a pathway to recovery.”

The Center for Biological Diversity, a national nonprofit, celebrated the news but at the same time expressed concerns about changes by the Trump administration to the very act that helped bring the nene back from the brink of extinction.

“We love an Endangered Species Act success story,” said Maxx Phillips, the center’s Hawaii director. “In this instance, nene have made remarkable bounceback on Kauai and are steadily growing on other main Hawaiian islands. But in no way has this animal gotten back to its original abundance and glory.”

She noted that the downlisting of the nene comes just months after Bernhardt finalized revisions to key ESA regulations — numerous rollbacks, she said, that could result in extinction for hundreds of animals and plants.

One of the most significant changes, she said, is the weakening of protections for threatened species. Currently, under what’s known as the 4(d) rule, the same protections are automatically extended to threatened species as provided to those listed as endangered, but this is no longer the case.

“The ‘4(d) rule’ has been an important rule to ensure these imperiled species can continue on,” she said. “We’re extremely fearful that this won’t continue in the future, and it could mean our nene are on the line again.”

The center noted that although the Trump administration has delisted several species, it has failed to protect many others on the verge of extinction. To date, the Trump administration has protected only 21 species under the act, it said, the lowest of any at this point in a presidential term.

In contrast, the center said, 360 species were protected under the Obama administration, 523 under Clinton, 232 under George H.W. Bush, 62 under George W. Bush and 254 under Ronald Reagan.

Nene, which are endemic to Hawaii, once thrived across the state. Their population dwindled due to hunting and introduced predators. By the mid-20th century, fewer than 30 remained in the wild on Hawaii island, while another 13 lived in captivity.

The nene was listed as an endangered species in 1967.

According to the Department of the Interior, due to collaborative efforts in following decades, some 3,000 captive-bred birds were released at more than 20 sites, including national wildlife refuges, national parks and state and private lands, across the state.

Today there are more than 2,800 nene, with stable or increasing populations on Kauai, Maui and Hawaii island, as well as a new population established on Molokai.

Ongoing threats to nene include predators such as mongooses and cats, along with habitat destruction and strikes by vehicles.

Robert Masuda, DLNR first deputy, said much work remains to be done.

“While we pause to celebrate this hard-won milestone for Hawaii’s state bird, there are many more species, plants, and animals, here in Hawaii that are equally imperiled as the nene once were,” said Masuda in the news release. “Hawaii is the endangered species capital of the nation with over 500 federally-listed threatened or endangered species and which will all need equal attention and effort from all of us to reverse their current courses toward extinction.”