A US judge has reinstated protection for grizzly bears in and around the Yellowstone National Park, ending plans for the first licensed trophy hunts in the region for decades.

District judge Dana Christensen ruled Donald Trump’s administration failed to properly consider the long-term survival of the species when it stripped the bears of their endangered status.

The US Fish and Wildlife Service (FWS) lifted federal protections for the roughly 700 grizzlies in the Rocky Mountains in 2017, paving the way for hunting to resume in Idaho and Wyoming.

Legal challenges from conversation groups and Native American tribes delayed what would have been the first hunts in either state for 44 years and the first outside Alaska since 1991.

Mr Christensen said the case was “not about the ethics of hunting” but whether federal officials had adequately considered threats to the long-term recovery of the grizzly population.

He noted that an estimated 50,000 bears once roamed the US and said it would be “simplistic at best and disingenuous at worst” not to consider the depleted status of the species outside the Yellowstone region, one of the few areas in their historical range where they have bounced back.

The Montana district judge found the government had failed to apply the best available science, as required by law, in evaluating continued threats to grizzly populations.

In a 47-page ruling, Mr Christensen called the FWS’s reasoning in lifting protections “illogical.” He pointed to two studies cited by the agency that actually contradicted its own conclusions that the species could remain self-sufficient.

The decision, which caps one of the most high-profile legal battles over the Endangered Species Act in many years, was celebrated by environmentalists but greeted with dismay by farmers and state officials.

“The grizzly is a big part of why the Yellowstone region remains among our nation’s last great wild places,” said Tim Preso, a lawyer for environmental legal organisation EarthJustice, which represented four groups that challenged the lifting of the hunting ban.

“This is a victory for the bears and for people from all walks of life who come to this region to see the grizzly in its natural place in the world.”

Andrea Santarsiere, a senior lawyer at the Centre for Biological Diversity, said: “Facing ongoing threats and occupying a fraction of their historic range, grizzly bears are nowhere near recovery. These beautiful and beleaguered animals certainly shouldn’t be shot for cheap thrills or a bearskin rug.”

Native American tribes, which revere the grizzly as sacred, had joined environmental groups in opposing the hunts. They said reinstatement of the threatened status was essential to protect their religious practices.

Agricultural groups, hunters and the National Rifle Association had all lobbied against the bears being relisted as an endangered species.

Cody Wisniewski, spokesman for the the Wyoming Farm Bureau, said restoring protections would allow the grizzly population to grow unchecked, “endangering the lives and livelihoods of westerners who settled the region long ago”.

Wyoming governor Matt Mead, a staunch critic of the Endangered Species Act, said he was “disappointed” by the judge’s ruling. He said the state had spent $50m (£38m) on the management of grizzly bears over the past 15 years.

The FWS said it was reviewing Monday's ruling and "considering next steps". Spokeswoman Jennifer Strickland added the agency stood by its decision to lift protections on the Yellowstone grizzlies, which government biologists contend are thriving.

The region's bears were first classified as a threatened species in 1975 after widespread shooting, poisoning and trapping caused their numbers to dwindle to just 136.

The Trump administration's decision in June last year to "de-list" the grizzly, a move first proposed in 2016 under Barack Obama's presidency, was based on the FWS's verdict that their numbers had rebounded enough that federal protection was no longer necessary.

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Environmentalists warned that while grizzlies had made a comeback, their recovery could falter without continued safeguards. They pointed to changes in the bears' food supply due to climate change and human threats posed by poachers and road traffic.

Management of the bears falls on the states of Montana, Idaho and Wyoming.

Montana decided against allowing a trophy hunt this year, citing concerns about long-term recovery of a bear population.

The other two states issued licences that would have allowed up to 23 bears to be killed. Thousands of people applied for licences.

The hunting season had been due to begin in both Idaho and Wyoming on 1 September but was halted while Mr Christensen considered whether to reinstate protections. His ruling on Monday makes permanently blocks the hunts from going ahead.

The decision comes as the Trump administration seeks to rewrite the Endangered Species Act, a move scientists warn would erode wildlife protection for the benefit of commercial interests.