Botanist Ted Hendrickson grabbed a fistful of black muck and tossed it toward the construction cranes busily building foundations for hundreds of homes on what was once prime Florida wetlands.

"I'm not saying this isn't a nice place to live. It just never should have been built," Hendrickson said as he pointed to Weston, a half-finished development of 2,200 homes so far.Weston, with homes priced between $75,000 and $1 million, is pushing green lawns and two-car garages deeper into the Everglades than any previous South Florida development has gone.

Such construction, Hendrickson said, destroys the irreplaceable.

"They have to destroy these soils to build on them, and nothing man creates can bring them back," he said. "No mitigation can replace up to 4,000 years of soil formation."

Hendrickson is one of a growing number of scientists and state officials who say that state laws that let developers destroy sensitive ecological areas as long as they promise to "mitigate" the damage by building or preserving other wetlands have failed to protect Florida's fragile environmental habitats.

State officials were to ask the Legislature Tuesday to put more teeth in the process.

According to a recent study by the state Department of Environmental Regulation, fewer than one-fifth of the state's manmade wetlands function as well as the natural systems they replace. And a third of the time, developers don't follow through on promises to replace destroyed wetlands, the study said.

Critics also complain that wetlands often lose out in political negotiations between officials and developers.

Weston's developer, Arvida JMB Partners of Boca Raton, has agreed to build 348 acres of wetlands and turn 265 acres of soggy farmland and malaleuca trees into deep water areas of habitat in exchange for being allowed to drain and fill 1,652 acres of wetlands.

The National Wildlife Federation maintains the developer should have been ordered to replace an additional 600 to 1,200 acres.

The Army Corps of Engineers approved the Weston agreement over the objection of Chuck Schnepl, the agency's supervisor in Miami. Schnepl determined that virtually all of the Weston property qualified as wetlands.

"The Corps of Engineers, by cutting a deal with the developer, has essentially picked the pocket of the public," said David White, a National Wildlife Federation attorney. "The law requires these decisions to be made on science, not political deal-making."

Arvida officials said replacing one-third of the wetlands is a fair trade.

"We'll be replacing low-quality wetlands with higher quality wetlands. . . . we're going to build lakes that look more like God-made lakes," said Ted Brown, Arvida's general counsel.