BILLINGS, Mont. >> Yellowstone National Park’s superintendent said today that he’s being forced out as a “punitive action” following disagreements with the Trump administration over how many bison the park can sustain, a longstanding source of conflict between park officials and ranchers in neighboring Montana.

Superintendent Dan Wenk announced last week that he intended to retire March 30, 2019, after being offered a transfer he didn’t want. He said he was informed this week by National Park Service Acting Director Paul “Dan” Smith that a new superintendent will be in place in August and that Wenk will be gone by then.

“I feel this is a punitive action, but I don’t know for sure,” Wenk told The Associated Press.

He wasn’t given a reason and said the only dispute he’s had with U.S. Interior Secretary Ryan Zinke, who oversees the park service, was over bison.

Ranchers in neighboring Montana have long sought reductions in Yellowstone’s bison numbers because of worries that they could spread the disease brucellosis to cattle and compete with livestock for grazing space outside the park. Brucellosis causes animals to prematurely abort their young and can be transmitted through birthing material. It also can infect people.

Park biologists contend the population of more than 4,000 bison is sustainable. But Zinke and his staff have said the number is too high, Wenk said, and raised concerns that Yellowstone’s scenic Lamar Valley is being damaged by overgrazing.

Zinke, a former Montana congressman, has paid close attention to projects back home, stirring speculation that he has future political ambitions in the state.

Interior spokeswoman Heather Swift declined to comment directly on Wenk’s assertions or the issue of bison management. She referred the AP to a previously issued statement saying President Donald Trump had ordered a reorganization of the federal government and that Zinke “has been absolutely out front on that issue.”

Wenk said he had multiple conversations with Zinke and his staff about bison, most recently this week.

“We’re not a livestock operation. We’re managing a national park with natural systems,” he said. “We do not believe the bison population level is too high or that any scientific studies would substantiate that.”

The livestock industry wants Yellowstone’s bison herds reduced to 3,000 animals, a population target specified in a 2000 agreement between Montana and the federal government. Montana Stockgrowers Association interim vice president Jay Bodner said Zinke “understands the issues around bison, not only in the park but how that impacts the livestock issue.”

Wildlife advocates who want changes to the 2000 agreement expressed dismay at Wenk’s ouster.

Thousands of park bison were shipped to slaughter during his tenure to keep the population in check. Wenk sought to curtail the killings with fledgling efforts to transfer surplus bison to American Indian tribes and expanding where the animals are tolerated in Montana.

“We’d hate to set the rug get pulled out from under that with a change in leadership,” said Caroline Byrd with the Greater Yellowstone Coalition.

Wenk has spent more than four decades with the National Park Service and seven years in Yellowstone. When he initially announced his retirement, he said he didn’t view his proposed transfer to the Washington, D.C., area as political.

A recent investigation into 35 personnel reassignments proposed in the Interior Department under Zinke revealed that 16 senior employees viewed their moves as political retribution or punishment for their work on climate change, energy or conservation. However, the Interior Department inspector general was not able to determine if anything illegal occurred because agency leaders did not document their rationale for the moves.

Yellowstone straddles the borders of Montana, Wyoming and Idaho and was established in the 1872 as the first national park. Under Wenk, it has struggled with a sexual harassment scandal that echoed problems in other national parks and prompted personnel changes in some instances.

Members of Yellowstone’s maintenance department were disciplined last year after an investigation found female employees faced sexual harassment and other problems.

Wenk said those problems never were brought up in the discussions about his possible transfer or retirement.

National Park Service Midwest Region director Cam Sholly will be installed as the new superintendent, Wenk said. Sholly is a Gulf War veteran and former member of the California Highway Patrol who previously served as chief ranger of Yosemite National Park.

Jonathan Jarvis, head of the park service under President Barack Obama, described Sholly as a strong leader and good choice to replace Wenk. But Jarvis said Zinke and his team would have an expectation of loyalty from Sholly that they could not get from someone such as Wenk, who already had the post when Trump took office.