TNC has also provided financial assistance. During a three-year drought, the nonprofit bought hay in the winter so that cattle wouldn't graze especially parched land.
Redd says she is pleased with the partnership and with TNC as well.
Larisa Barry, director of communications for the Utah chapter of TNC, said, "[Heidi] understands that it makes business sense to see the land survive."
Although ranches operated by nonprofits affect large tracts of land near national parks, those land sales represent only a small fraction of the total rangeland turnover.
Far more significant are sales to weekend ranchers, who, like conservation groups, tend to value the natural environment over livestock production.
Weekend ranching is so common in the West now that a study by the New Mexico State University Corona Range and Livestock Research Center found that only 25 percent of a ranch's market value in New Mexico relates to its income-earning potential.
The wealthy buyers are interested in scenic beauty and recreational opportunities, such as trout fishing or skiing, says Bill Travis, professor of geography at the University of Colorado at Boulder.
Travis co-authored a 2006 survey, published in the journal Society amp; Natural Resources, which studied land-ownership changes in ranchlands surrounding Yellowstone National Park between 1990 and 2001.
The survey found that wealthy buyers purchased 40 percent of the ranches on the market, compared to 26 percent bought by traditional ranchers.
In some parts of the region, weekend ranchers now outnumber the traditional ones.
According to Travis, there are a number of reasons why traditional ranchers sell their land. Family dynamics and retirement are two. "But the main reason is an offer to buy," he said.
Once a wealthy new owner moves in, the cattle generally move out. There may be a ranch manager, but there are few, if any cattle, on the property. This results in less grazing and less attempts to control wildlife.
Weekend ranchers view wild animals as an amenity not as a threat to their livelihood, Travis says.
This laid-back approach to ranching doesn't necessarily mean that wealthy buyers use a hands-off approach to land management. They often make improvements, but they are far more likely to build a fishpond than an irrigation system.
In some cases, the owners work with experts to restore natural ecosystems.
Travis believes that weekend ranchers are improving the biodiversity of the West, and he's optimistic about the long-term effects of the trend.
"I've seen the changes with my own eyes," he said. "I don't know how it can't be good."
Free Email News Updates
Best Online Newsletter, 2006 Codie Awards
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES