In the vast and arid expanses of New Mexico, America's conservationists are now demanding control of the land that cowboys have grazed since the end of the Indian wars; and increasingly, they are winning it. "The public and the government are in love with the cowboy", says rancher Sterling Spencer, "but they don't like the cow. The threat we're facing is the misconceived idea that cows are ruining the land. Those people will probably make the ranching way of life, the cowboy and the westerner extinct in my lifetime."

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New Mexico's Catron County is used to range wars: the Apache chief Geronimo and Billy the Kid both fought here. Since the turn of the century the cowboy has been in charge. Cattle outnumber people 10 to one here - in a county the size of Wales.

Yet the cowboys don't own the land. Much of the American West, contrary to stereotypes about sturdy homesteaders, belongs to the state or federal agencies. To the east, in Texas and the Midwest, where the beef industry is concentrated, ranches are privately owned. But in a swathe of state from New Mexico up to Wyoming, most cattlemen must apply to the Bureau of Land Management or the Forest Service every few years to renew their grazing permits. Increasingly, those permits are being denied or hedged about with conditions.

Kit and Sherry Laney had to leave their lanch for a room without water or electricity

That's what happened to Kit and Sherry Laney. Once they had a working, though basic ranch and grazed hundreds of head of cattle by a river bank. But when they applied to have their permit renewed, they were told the animals could no longer feed there, as they'd damage the environment for native wildlife.

So the Laneys have had to pack up and move, and now lead a far tougher existence miles away, without electricity or plumbing.

The latest and most onerous condition applied to New Mexico's ranchers excludes all cattle from 250 miles of riverbank along the Gila River and its tributaries. This follows a landmark legal ruling that endangered bird and fish species depend on the river for survival. Since the passing of the Endangered Species Act in the 1970s, American courts have had the power to protect the environment, but it's only in the past ten years or so that the Act's full potential has been harnessed by the endangered species' champion: the Southwest Center for Biological Diversity. Based in Arizona, they have already used the Act to shut down the logging industry across most of the Southwest. Now they are turning their attentions to ranchers.

The Center points out that cows, adapted to life in fertile agricultural land, can have devastating effects on the indigenous wildlife of this more fragile ecology where water is scarce. Michael Robinson, one of its staff, insists that " The culture of ranching has been an unmitigated series of brutal acts. It's an oligarchy of people who conquered the land and others who bought in to the romance. They put on cowboy hats and think they're kings of the earth."

Tim Whewell with Todd Schulke of the Southwest Center for Biological Diversity

It's true that the cowboys, symbols of self-reliance, have actually been cosseted by the government for years. It costs just $1.35 - less than �1 - to graze a cow on federal land for a month. Rates on private land would be six or seven times higher. Ranchers get flood and drought payments and subsidies to build fences and water tanks.

In effect, say environmentalists, they get paid to trash the land. According to Todd Schulke, a zoologist working with the Center, the Gila valley is the only river basin in the world where every native fish species have been wiped out or recommended for listing as an endangered species.

Cattlemen, in turn, accuse government agencies of degrading grassland by suppressing fires and encouraging too many trees. They point to the recent reintroduction of the Mexican grey wolf to national parks as a case of the American public's infatuation with wilderness rather than people. Western cowboys feel the political tide has turned against them. Votes in the West come from big cities like Denver and Phoenix, which tend to view the wilderness as a playground for self-discovery rather than a working territory.

But it might be that very attitude - the thirst for some wild places where city folks can go to recharge - which proves the eventual salvation of the West.

Preston Bates shows Tim around the N Bar Ranch

Two hours' drive down a dirt track from the main road, Preston Bates runs a new style of ranch: one which herds tourists as well as cattle. Despite the traditional western disdain for service industries - Preston notes that " for a cowboy to sink to wrangling dudes - it's the bottom of the barrel in a lot of people's minds round here" - keeping visitors on the ranch doesn't just bring in cash: it also helps reconcile cattle and conservation.

Out on their rides, wildlife photography courses and birdwatching expeditions, his guests can also take the cows to graze well away from the river beds, rotating the pasturing far more thoroughly than was possible before. It might seem like Wild West Lite - the wilderness as theme park for townies - but as Preston points out, "there's three and a half million acres of public land out here that is just waiting to be used in a different way." The future of the West itself , and that of the remaining cowboys, depends on finding those ways.