Automatic federal spending cuts in January would force cuts in personnel and research funding at U.S. EPA and national parks, according to a new report by four environmental groups making the rounds on Capitol Hill.

The study by the Wilderness Society, the Natural Resources Defense Council, the National Parks Conservation Association and Defenders of Wildlife says the looming sequestration would be "extremely harmful" to various agencies, primarily EPA.

Though House Republicans have pushed to rein in the agency, the sequestration would hit EPA with deep budget cuts it has been able to avoid. The cuts, the report says, could impede EPA's management of air and water pollution standards, as well as reduce federal investments in renewable energy projects and force closure of up to 187 parks.

The Office of Management and Budget's report on sequestration impacts identified a $183 million reduction in the National Park Service's operations account, the groups assert.

"We're now in a situation where the deadline is fast approaching and inaction has kind of led us to a point where we really do need to start letting people know what this is going to mean because it's not a year away, it's imminent," the Wilderness Society's Alan Rowsome said. "Our hope in putting this report out as part of the story is to urge members to work in a bipartisan way across the aisle to find a deficit reduction solution that doesn't further damage investments in environmental programs."

The cuts, the report says, could result in a decrease in wildfire prevention programs and an increase in invasive species overgrowth. The Land and Water Conservation Fund would not be able to care for certain Civil War battlefields, it says. And the National Oceanic and Atmospheric Administration would be forced to reduce resources for its coastal and estuarine conservation program, among other things.

Although no one knows exactly which activities would be directly affected, Rowsome said each program would experience a cut. "It's difficult for us, I think, to game out all of the possible solutions, all of the possible permutations of different budget deals," he said. "The one thing we can do, however, with a relative certainty, if we don't find a way to deal with automatic spending cuts, here are some of the things your constituents are likely to see."

Lacking clarity from OMB, the groups said they based their findings on interviews with current and former federal officials and on examinations of how conservation- and land-focused agencies have handled cuts in the past.

Nearly every major interest group has been urging lawmakers to avert sequestration, but giant defense companies have garnered much of the spotlight. With this report, the groups intend to shift more attention their way.

"These programs have already been cut over the last two years, are struggling with years of underfunding, and will already face years of challenges under the spending caps in the Budget Control Act," the groups wrote, adding, "They are not the place to seek an answer to our nation's fiscal imbalance."

While the groups have not officially released the report, some congressional staffers said they got a copy and have been reviewing it. Several staffers suggested the report could factor into lawmakers' arguments for averting sequestration.

House and Senate leaders are expected to consider ways to avert the automatic cuts through additional spending cuts, revenue increases or both when they return to Washington for a lame-duck session Nov. 13. Otherwise, in January, the cuts, which include more than $500 billion in defense spending over 10 years, will begin under the Budget Control Act of 2011.