ST. PAUL  — A renowned bear researcher known to hand-feed the animals and broadcast the birth of cubs over the Internet lost his Minnesota permit Friday to do his close-up studies.

The Minnesota Department of Natural Resources informed 74-year-old Lynn Rogers that he wouldn’t get a new permit to radio-collar wild bears or videotape them in their dens.

In a letter to Rogers from DNR Commissioner Tom Landwehr, the agency said it had repeatedly warned the researcher, who is based in Ely of concerns about public safety because the wild bears were becoming too comfortable approaching humans. Rogers has been licensed to do his technology-assisted research on wild bears since 1999.

Rogers has until July 31 to remove the collars. He still has a game farm permit for an education center where he has domesticated bears.

“Because of these ongoing concerns, it is clear the potential benefit of published research is greatly outweighed by our continuing concerns for public safety,” Landwehr wrote. He adds that there are documented incidents of “extremely unprofessional behavior with research bears” by Rogers.

Rogers said he considers the allegations “unfounded” and fears the action imperils his research.

“It’s the end of my career, a 46-year career,” Rogers told The Associated Press, adding: “It’s a kill-the-messenger type of thing they’re doing.”

He disputes that he’s jeopardizing humans with his methods. Rogers said getting close to bears, as he has, is essential to studying the biology of interactions between bears and humans. Without radio collars, Rogers said he doesn’t think he will be able to adequately track the same bears in a way that allows him to build up trust.

Rogers’ work gained a following far outside Minnesota after he began placing cameras to monitor bears and beamed their feeds to the Internet. Thousands of people watched live as one bear, Lily, gave birth to a cub named Hope, and a corresponding Facebook page drew more than 100,000 likes.

DNR officials said 50 wild bears are under Rogers’ supervision, with about a dozen collared at any time.

“These bears are putting their noses in cars. They’re going onto peoples’ porches. They’re coming into their backyards,” said Lou Cornicelli, the DNR’s wildlife research manager. “A conservation officer had to kill a bear that went into a garage and wouldn’t leave.”

The DNR also questioned whether Rogers has produced adequate peer-reviewed published research from the bear studies, which Rogers also disputed.

Cornicelli said the decision is not open to appeal, and Rogers said he didn’t know if there was any legal recourse. So he plans to reluctantly comply.

“If you try to continue when they pull your permit, you just get arrested,” Rogers said.