As New Jersey lawmakers consider how to implement a constitutional amendment approved by voters in November to dedicate funds for the preservation of open space, environmentalists are lobbying to carve out money for their pet causes.

But here's the catch: Lawmakers must pass a bill that would be palatable to Gov. Christie, a Republican preparing to run for president in 2016, who could veto a measure he doesn't like or similarly strike language from the budget in June.

"We have to find a way to at least make the open-space portion of the budget some way supportable by the governor," Sen. Bob Smith (D., Middlesex), chair of the Senate Environment and Energy Committee, said at a recent legislative hearing.

"This is the chess game. It can be quite difficult."

Prior to the amendment, 4 percent of Corporation Business Tax revenues were dedicated to various environmental programs, including water quality and hazardous-site cleanups.

Starting the fiscal year that begins July 1, the amendment calls for most of that money to be reallocated to the preservation, acquisition, and stewardship of open space for recreation and conservation - previously funded through a bond referendum.

Starting in fiscal year 2020, the percentage of business tax revenues dedicated to open space will increase to 6 percent.

In his budget for fiscal year 2016, Christie proposes $80 million for open-space preservation, in accordance with the amendment. Traditionally, the state has spent about $200 million annually on open space.

The amendment set big-picture guidelines on how to spend the money - 71 percent must go toward open-space preservation through fiscal year 2019, for example - but didn't specify how to divvy up the cash within that broad category.

Consequently, something of a war has erupted among nonprofits that want to take care of the land the state has already preserved and public-interest groups like the Sierra Club that prefer to acquire more land, particularly for growing cities.

The amount of money proposed for farmland preservation is also being hotly debated.

"To give money to nonprofits to plant butterfly bushes when we don't have money for parks in urban neighborhoods is unconscionable," said Jeff Tittel, director of the New Jersey Sierra Club.

He noted that the amendment decreased funding for brownfields and other programs that have traditionally helped cities. Therefore, it's important to set aside money in the open-space fund for urban areas, he said.

Tittel noted that the Green Acres program, which was established in 1961 and has helped preserve some 675,000 acres, has never accounted for stewardship.

Tom Gilbert, chairman of the NJ Keep It Green Coalition, said that historic lack of funding for stewardship had only made spending on it more necessary.

"There's a race to save the important parcels for various reasons," said Gilbert, whose organization represents more than 180 environmental groups in the state. "But at the same time, you have to take care of the land that has been set aside. There's always been a challenge to fund both of those things adequately."

Stewardship is needed to root out invasive species crowding out native ones, he said, or to fix up deteriorating playgrounds.

But Tittel and others argue that the definition of stewardship is too broad in the two bills advancing through the Legislature.

That could result in wasteful spending, they say, especially considering the state's tight budget.

"The question at the end of the day is, what is stewardship and how is it going to be implemented?" said Assemblywoman L. Grace Spencer (D., Essex), chair of the Assembly Environment and Solid Waste Committee, which held a hearing on the matter Thursday.

Her bill defines it as "an activity, beyond routine operations and maintenance, undertaken by the State or a local government unit to repair, restore, or improve natural resources on lands acquired or developed for recreation and conservation purposes."

"If we can't get a good definition of stewardship, we'd rather have no funding," Dave Pringle, campaign director for Clean Water Action, told lawmakers Thursday.

Alternatively, Pringle said he'd prefer Christie's plan to spend $20 million on staff to steward the land, "rather than have it to go to NGOs for who knows what."

Gilbert, of the NJ Keep It Green Coalition, said that money for staff salaries should come from the general fund, as it has previously, not from the voter-approved amendment.

A spokesman for the state Department of Environmental Protection said this redirection of funds was "clearly permitted" by the amendment.

"My guess is that if we had no staff working on upkeep or improvements to our state parks and they weren't kept to a high level or if we had to even close a park, the 16 million visitors who enjoy them annually might have something to say about it," said the spokesman, Bob Considine.

Nonprofits that apply for open-space grants are required to match state funding, so "there's a huge bang for the buck," Gilbert said.

Gilbert and other environmentalists say Spencer's bill doesn't provide enough funding for stewardship - about $2 million, with none explicitly allocated to nonprofits.

Smith's bill, which allocates about $7 million to stewardship, more closely aligns with NJ Keep It Green Coalition's goal, Gilbert said.

aseidman@phillynews.com

856-779-3846 @AndrewSeidman