The Interior Department started an effort this week to get a conservation program that turns 50 this year over the hill, but first it needs to make sure House Republicans don't push it over a cliff.

The Land and Water Conservation Fund, a matching grant program that gets its funding from federal offshore oil and gas revenue, is running up against the clock. Its $900 million authorization expires next year, and the Obama administration and its environmental allies need the support of GOP lawmakers to keep it alive.

"Without action from Congress, the fund will disappear within a year," Interior Secretary Sally Jewell said during a Monday media call about the program, which is a chief driver for parks, hunting and fishing opportunities, green space and Civil War battlefield maintenance. The administration is also portraying it as part of its broader climate change efforts, as it has sought to expand natural buffers such as wetlands and forests that mitigate flooding and other extreme weather events linked to climate change.

The signs from House Republicans are mixed. The draft fiscal 2015 spending bill the Interior and Environment Appropriations subcommittee is scheduled to mark up Wednesday proposes $152 million for the Land and Water Conservation Fund, less than half of enacted levels for this year.

Still, that's a marked change in one key way — House Republicans initially suggested zeroing out the fund last year.

A closer look, though, reflects the pattern of House GOP spending priorities in recent years, noted Amy Lindholm, who heads the Wilderness Society's Land and Water Conservation Fund efforts. None of the federal projects President Obama outlined in his budget request -- in which he called for full, permanent funding for program -- received a dime. Civil War centennial projects and Fish and Wildlife Services-administered easement projects aiding hunters and anglers also were gutted.

Nick Loris, an economist who focuses on energy and environment issues at the conservative Heritage Foundation, said that's all for the best because it would restrain federal ownership of land.

"I’d rather do away with the program and rather have the states use their money to finance conservation projects how they see fit. The federal government already owns a good chunk of America’s land and does a poor job with stewardship and maintenance," Loris said in an email.

Shortfalls are par for the course when it comes to the Land and Water Conservation Fund, as it's only been fully funded once in its history. And, in any event, prospects of the bill reaching the floor are grim due to time constraints and the inflammatory nature of anti-Environmental Protection Agency measures, such as handcuffing proposed power plant emission rules, included in the legislation.

It's the authorization battle that takes precedence this year, supporters say.

While the Land and Water Conservation Fund is included in the same bill as EPA programs — making it a sensitive piece of legislation — it's possible to vote on it separately.

The fund also has two other things going for it: It has many Republican supporters, a product of its backers in the hunting and fishing community; and it's generally not a major GOP priority, making it less likely to be held hostage.

"If you were to bring the program up for an up-or-down vote in either chamber, it would have broad support," said Matt Lee-Ashley, a senior fellow who works on conservation issues at the left-leaning Center for American Progress.

But given the general GOP mood about the role of federal government in owning land, reauthorization is still an "uphill climb," he noted.

That's why Jewell began touring the country this week in support of the program. She met with Fort Worth, Texas, Mayor Betsy Price on Tuesday and announced $43 million worth of grants to states through the fund, and she'll be in Birmingham, Ala., and Richmond, Va., to round out the week.

Despite her scheduled trips to red-leaning states, Jewell said she hasn't talked to specific House Republicans — "This is all a moving target," she said to a question from the Washington Examiner — but that her outreach effort is more to highlight the support the Land and Water Conservation Fund has off Capitol Hill.

That, too, is the goal of conservation groups that are planning events commemorating the program's 50th anniversary.

"It's part of what has been a re-energized commitment to conservation that we've seen over the last few months," Lee-Ashley said. "Those things together represent a major conservation legacy for the administration, but also in practical terms the LWCF is the way our country has funded parks in the last half a century."