It has taken sweat, serendipity and five hours for Matthew Schwartz to find a single paw print of a Florida panther stamped in the swamp muck.
He has bushwhacked through knee-high saw grass and saffron-colored love vine in search of the predator's milieu. But winds across the fields must be easterly, or planes headed to the Fort Lauderdale airport will chase the big cats into the remotest corners of the preserve.
"There it is!" proclaims Schwartz, a Sierra Club outing leader from Broward County, his victorious tone tempered by the long search. "You can tell it's a panther because it's so much bigger than anything else that shape."
Schwartz's voice comes in relative silence, in an area of the preserve known as Bear Island. Off-season rainstorms have halted blasting at the limestone mines 10 miles away, and off-road vehicle access to the area has been suspended for four months.
The edict against ORV use is only a pause while the trails are stabilized with gravel. It was the temporary nature of the suspension -- and the fact that the trail work will essentially make the ORV roads permanent -- that led to a lawsuit by conservation groups, including the Sierra Club, in November. They allege that ORV access to the sensitive area constitutes federal neglect of the National Park Service's obligation to protect the highly endangered panthers.
The environmental groups -- also including Defenders of Wildlife and the National Parks Conservation Assn. -- sued the park service for reopening the northwest corner of the preserve to ORVs a year ago, contending that the rigs have churned up delicate ground cover and altered water flows in the protected wetlands.
About 20 miles of newly carved ORV tracks in the northwestern Bear Island Unit of the preserve are in dispute, but the activists note that the wide swaths of herringbone-print gouges cut across the most important terrain for the panther.
"The basic feeling is that, with 23,000 miles of trails [throughout the preserve], that we can afford to close 20 to 30 miles to make sure the panthers are not adversely affected," Jonathan Lovvorn, attorney for the Humane Society of the United States, says of conservationists' push to ban ORVs from Bear Island.
"I don't think we need to find a panther with ORV tracks across his back to know this is having an effect."
Off-road vehicles were prohibited in 2000 in much of the region north of Interstate 75, known as Alligator Alley. But preserve superintendent Karen Gustin decided to reopen the Bear Island area to ORV use a year ago after a heavy lobbying effort by the off-roaders.
"Bear Island is not the only area where panthers exist in Big Cypress," Gustin said. Wildlife biologists have tracked panthers tagged with radio collars roaming throughout the 729,000-acre preserve, she said.
The previous prohibition against ORVs was influenced by a drop in the panthers' numbers, which fell to about 30 in the mid-1990s. Eight Texas cougars were introduced to breed with the Florida cat.
"It was very successful. We currently have approximately 100 panthers in South Florida," Gustin said.
Schwartz of the Sierra Club counters that 15 panthers were killed in vehicle collisions last year, dropping the population closer to 80. None died due to ORV hits that he knows of, but he suspects the noise and habitat disruption from the off-roaders helped drive them onto highways.
Paul Souza, a field supervisor for South Florida from the U.S. Fish and Wildlife Service, confirms that a record number of panthers were killed in 2007. But he disputes that their mortality rate is the result of panthers' being displaced by ORV noise.
"I haven't seen any scientific evidence that would support that specific line of logic," he said.
The increased deaths and sightings of the panthers on the populated fringes of the preserve "reflects growing numbers of panthers and the fact that we have more development and more people than we had in the past," Souza said.
Because of the pending litigation, Gustin said she couldn't discuss what effects ORV traffic might be having on the panthers. But she conceded that with rising air traffic, mining and growth, "we do have some kind of impact, and I don't think anyone would deny that."
Those influences affect more than the panthers.
Off-road vehicle tires have plowed away the trails' thin veneer of periphyton, a soil-like stew of algae and fungi that the preserve's unique vegetation needs to grow.
As ruts fill with water, off-roaders have veered wider to get around the mud pools, transforming footpaths into broad mires that neither man nor machinery can negotiate. Once-prolific orchids, bromeliads, herbs and wildflowers cannot grow.
It is those damaged swaths of prairie, 70 feet wide in places, that officials are trying to stabilize. By laying a rubber-like honeycomb mat known as geotextile onto the exposed limestone, then topping it with gravel, officials hope to give off-road drivers better traction.
As Schwartz surveyed one of the most damaged areas, he pointed out the vegetation trampled by vehicle tires. A few swamp-buggy widths away stood a waist-high long-leaf pine that the former school counselor calls Cousin Itt for its unruly, hairlike sprouts of golden needles.
The preserve has capped at 2,000 the number of ORVs licensed. The rigs are prohibited in all national parks, such as the Everglades immediately south of the preserve, and part of the rationale in expanding access to Big Cypress has been acknowledgment of off-roaders' rights to use some public lands, Gustin said.
Off-road enthusiasts contend they are unfairly cast by conservationists and media as enemies of the wilderness.
Lyle McCandless, head of the Big Cypress Sportsmen's Alliance, said: "All I'm going to say is that my alliance is putting forth great efforts in protecting the ORV rights and other rights given to the public by the 1974 act of Congress that created the preserve. Our opponents -- the environmental extremists -- expect these public lands to be closed to anything other than foot traffic."
Repeated efforts to reach members of the preserve's off-road vehicle advisory board were unsuccessful.
Schwartz says the responsibility for any threat to the panthers lies with the park service and Fish and Wildlife, the government agencies that are the wilderness stewards.
"It's not a hunters-versus-hikers issue," Schwartz said. "It's not about people at all. If I were to put it simply, I would say it's about machines versus nature."