CHICAGO - Wyoming resident, Patricia Fazio, Ph.D. has filed a 
By JIM CARLTON
GOSHUTE VALLEY, Nev.—Nevada cattle ranchers, having long battled the land's harsh elements, now find themselves up against a new force of nature: Madeleine Pickens.
Jim Carlton has the story of why ranchers in Nevada are up in arms over a fence that the wife of billionaire T. Boone Pickens wants to erect on her property.
Mrs. Pickens, wife of Texas billionaire T. Boone Pickens, caused an uproar when she proposed the Bureau of Land Management let her fence off more than 500,000 acres of federal land to create a sanctuary for wild horses near a 14,000-acre ranch she bought in October.
Her proposal for the bureau to designate a "mustang monument" on those acres isn't sitting well in Nevada cattle country, where ranchers worry Mrs. Pickens's plan threatens to force them off the range. Nevada's estimated 450,000 cattle graze mostly on federally owned lands in a practice dating from the 19th century.
The Elko County Commission voted Nov. 3 to oppose Mrs. Pickens's plan. "What we're worried about is if she locks up ranches all over Nevada," said Commissioner Demar Dahl, a rancher.
If the plan went through, "something has got to give, and it will be cattle," said Robin Boies, a 55-year-old local rancher who grazes her cattle on federal land adjacent to her Nevada ranch. Hunters and off-road enthusiasts also object to the plan, saying it could bar them from a popular recreation area to which they have free access now.
Like many ranches in the West, Mrs. Pickens's ranch includes the rights to graze stock on surrounding federal land in return for payments to the government and general upkeep of the land. Her proposed mustang monument would be on these federal lands around her ranch.
Mrs. Pickens says she wants to buy enough other Nevada ranches with grazing rights on federal lands to create sanctuaries for as many as 10,000 horses. "I'm sorry, but there's no putting this back in the bag," she said.
Jim Carlton/The Wall Street Journal
Madeleine Pickens visited U.S. land near her Nevada ranch in November.
Mrs. Pickens has been a frequent visitor to these parts since she began shopping for a ranch in 2008. She often flies from her home in Dallas into nearby Wendover, Nev., in her husband's private Gulfstream 550 jet, then shuttles in by helicopter.
Last month, her rented American Eurostar AS 350 chopper set down in the parking lot of a casino in Wells, Nev., where she stepped out in riding boots, riding pants and a faux-fur jacket. Later that day, accompanied by her dachshund, Tommy, she surveyed sage-covered Nevada landscape as the helicopter banked low over a herd of galloping mustangs.
"Oh, pure joy," Mrs. Pickens said as five mustangs raced below the chopper toward a line of distant mountains. "I'm just glad they're out there."
Mrs. Pickens, 63, says the mustang preserve would be open to the public. And while she says local support would be nice, she says she has backing from the Bureau of Land Management. Bureau spokesman Tom Gorey wouldn't comment on the proposal except to say it was under review. "All the naysayers can nay as much as they want," Mrs. Pickens says.
Mr. Pickens, 82, who has become an apostle for clean power such as wind in recent years, is unwilling to bet against his wife of five years. "I tell you one thing, you get a woman who has made up her mind to do it, and she has money, she'll do it," he said. "You give her an ax and she'll do the chopping."
A century ago, as many as two million mustangs, descendants of domesticated horses, roamed North America. Round-ups and slaughter cut their numbers sharply, to about 34,000 wild horses today. The 1971 Wild Free-Roaming Horses and Burros Act set aside federal land for them.
Bureau of Land Management officials say the horses have no predators in the animal world and can double in population every four years. The agency has removed nearly a quarter-million from the range since 1971, offering most for adoption. There are now nearly 10,000 more than federal land managers think the open range can sustain.
Almost 40,000 captured horses are also being boarded at government expense—prompting the bureau in 2008 to consider euthanizing them to curb costs.
That alarmed Mrs. Pickens, who owned racing horses with a previous husband, the late aviation tycoon Allen Paulson. She says she got out of that business after learning some of her horses ended up in the slaughterhouse. "I would cry at night," she said.
One morning, "I woke up with an epiphany—to buy a ranch and go to the BLM and get grazing rights for the horses," she said. In late 2008, she began meeting with the bureau and looking for ranches in Nevada.
She bought Spruce Mountain Ranch, gaining grazing rights on 540,000 acres of surrounding federal land. Under her plan, that and other sanctuaries would be operated by a nonprofit, Saving America's Mustangs. Mrs. Pickens says she is also in escrow to buy a 4,500-acre ranch along U.S. Route 93, where she hopes to set up a tourism village and conduct mustang tours.
At an Elko commission meeting Nov. 3, which Mrs. and Mr. Pickens attended, attendees lined up to speak out against her plan.
Some locals are supportive, particularly in Wells, which could gain a tourism boost from its location near the sanctuary. "The overall concept I have bought into," Wells Mayor Rusty Tybo told Mrs. Pickens in a meeting Nov. 15.
She nodded, and added: "I don't know how anything bad can come of it. As long as I'm alive, it won't."
Write to Jim Carlton at jim.carlton@wsj.com