Interior Secretary Ryan Zinke, who rode a horse to work on his first day as Interior Secretary, will leave the Trump administration by year's end/DOI

Interior Secretary Ryan Zinke, a lightning rod for conservationists and environmentalists and long portrayed by his critics as being in the pocket of the energy industry, will leave the administration by year's end, President Trump said Saturday.

“Ryan has accomplished much during his tenure and I want to thank him for his service to our Nation," the president said in a tweet.

And yet, Zinke has been under several investigations for the way he's run Interior and how he might have mixed personal interests with his position. One of those pending investigations has been looking into whether the Interior Department blocked a casino deal in Connecticut, while another regards conversations Zinke had with then-Halliburton Chairman David Lesar about a development project in Zinke's hometown of Whitefish, Montana. He also has been investigated by the Interior Department's Office of Inspector General for his travel and for treating his wife as if she were a federal employee.

The secretary also has drawn great criticism for his recommendation that President Trump greatly shrink both Bears Ears National Monument and Grand Staircase-Escalante National Monument, both in southern Utah; for directing the National Park Service to defer to states when it comes to fish and wildlife management; for ordering the Park Service to roll back hunting restrictions on predators in national preserves in Alaska; for claiming that one-third of Interior's 70,000-employee staff is disloyal to him and the president.

The Interior secretary, who was a member of Congress before the president nominated him, has antagonized Democratic members of Congress by largely ignoring them.

"We sent close to 60 to 70 inquiries, received no response on any of them from the secretary," U.S. Rep. Raúl Grijalva, who is expected to chair the House Natural Resources Committee in the new Congress, told the Traveler earlier this month. "We’re going to reissue those, so tone becomes how he responds to those and gets us the information that we are asking for now (that we're) the majority. So any followup to that, legally speaking, any options, whether there are subpoenas or not, are going to be entirely dependent on that response."

Secretary Zinke further eroded relations with Grijalva, specifically, by calling him a drunk after the congressman called on him to resign.

At the National Parks Conservation Association, President and CEO Theresa Pierno said Saturday that the organization long has worried about decisions the secretary made that it thought brought harm to "national parks, their wildlife and our cultural and natural resources."

"NPCA has consistently called on Mr. Zinke to uphold conservation policies that protect our public lands, but unfortunately, he failed to do so," she added. "Rather, Mr. Zinke took the opposite trajectory, charting a troubling course for our national parks and protected lands – from creating staff upheaval to carving up our national monuments for destructive development and fast-tracking oil and gas leasing processes in and near some of America's last truly wild places. His refusal to work effectively with the conservation community and his lack of leadership only adds to the difficulties our national parks and public lands now face."

Welcoming the secretary's departure was the Coalition to Protect America's National Parks, where Chair Phil Francis called it good news.

"With all of the ethics investigations of Secretary Zinke and with the recent report that morale in the Interior Department is one of the lowest in government, it is time for change," he said. "Never before have there been more attacks on public lands nor has their been less transparency in how decisions are made. That said, we continue to be concerned that problems will persist with regard to undue  influence by energy development and disregard of science in public policy decision-making.  We will continue to pay close attention to these and other matters as we move forward."

But Secretary Zinke's departure is not expected to alleviate the pressure on public lands to, above all else, produce energy. At The Wilderness Society, President Jamie Williams said Deputy Interior Secretary David Bernhardt "has made it his mission to stifle climate science and silence the public so polluters can profit. Unfortunately, even with Secretary Zinke out, the Interior Department remains disturbingly biased in favor of special interests over the health of American communities and the public lands that they love.”

Since becoming Deputy Secretary of the Interior, David Bernhardt has been the on-the-ground implementer of the Trump Administration’s ‘energy dominance’ regime.

At the Natural Resources Defense Council, Ana Unruh Cohen, managing director for government affairs, said Zinke was "wholly unqualified to lead the Department of the Interior."

"He lacks the ethics, integrity and the dedication to the agency’s core mission to act as a steward for America’s public lands, wildlife and natural resources. Instead of protecting our natural heritage, Zinke acted like the chief lobbyist for the oil and gas industries. If his successor also puts the interests of polluters ahead of safeguarding public health and the environment, he or she will encounter the same wall of resistance.”