More than 1,500 Florida Keys voters signed to help put a conservation-land referendum on the statewide November election ballot.
An effort led by Florida's Water and Land Legacy Campaign collected enough verified signatures from state voters -- 690,802 as of Tuesday -- to add the vote on an amendment to the Florida Constitution this fall.
"Those are just the ones validated so far by local elections supervisors," campaign manager Will Abberger said. "We're received more than 1 million."
A count showed 1,510 voters in Monroe County signed the amendment petition.
"Floridians care deeply about our natural resources and understand the importance of our environment and clean water to the economy," Abberger said. "That's especially true in the Florida Keys."
The Florida Supreme Court has approved the proposed amendment's language so it appears almost certain that the referendum will be on the ballot.
If approved by at least 60 percent of the November voters, the amendment would require that a third of taxes collected by the state from documentary stamps paid when real estate is sold be dedicated to buying land for conservation and recreation.
That could total $10 billion over the next 20 years, according to the campaign. If approved, it would take effect in July 2015.
The Florida Forever program, largely responsible for acquiring hardwood hammocks on North Key Largo and the Custom House in Key West, among other Keys projects, was virtually halted by state lawmakers five years ago because of economic slowdown.
"We started working on the amendment in 2009," Abberger said.
In some years, the state spent $300 million to buy sensitive lands threatened by development.
Three Florida Keys acquisition programs were funded by the Florida Forever program: The Florida Keys Ecosystem project, the Coupon Bight/Key Deer project and the North Key Largo Hammocks project.
All three encompass a total of 19,961 acres, of which 10,075 now are in state ownership.
Finishing the three Keys projects listed as Florida Forever priorities would cost an estimated $57.2 million, according to a Florida Department of Environmental Protection report.
Groups supporting the amendment campaign include the Trust for Public Lands, Audubon Florida, the Florida Wildlife Federation and the Everglades Foundation.