West from Sioux Falls, hundreds of miles of rolling South Dakota corn eventually morph into one of this country's largest remaining national grasslands, a portion of what is now the North American continent's largest endangered ecosystem.
Miles beyond the wide Missouri River, a small sign announces the beginning of the Buffalo Gap National Grassland's 600,000 acres; part of nearly 4 million acres of national grasslands administered by the U.S. Forest Service. The Buffalo Gap grassland is just one integral part of a tenuous sea of grass that stretches from southern Canada to Mexico; ranging from the eastern slope of the Rockies to the 100th meridian.
To the north, the Buffalo Gap grassland's panoramic carpet of dirty brown is set against a mostly clear sky. To the south and west, South Dakota's infamous Badlands lie in the distance.
"For most people, the grasslands are something you fly over or drive through," said Pete Bauman, director of community-based conservation at the Nature Conservancy's Clear Lake, S.D., office. "In the middle of summer or heart of winter, the prairie is miserable; a damned inhospitable place. They don't hold real strong appeal for people that weren't raised here. The prairie only offers up its treasures in spring and fall; at sunset and sunrise."
But the grasslands serve a larger eco-purpose — as natural buffers between forest and desert. Over millions of years, the grasslands evolved as the Rocky Mountains continually squeezed out moisture over what is now the Great Plains. Today, nearly all of this semi-arid region receives less than 24 inches of rainfall per year.
With its deep roots, tall grass like bluestem, switch- and Indian grass, can be shoulder-high in summer. In contrast, even in a good year, short grasses, like blue grama or buffalo, rarely grow above a few inches.
When Lewis and Clark first passed through the Northern Plains in 1805 and 1806, the prairies were thriving and pristine, although so open and so vast it's hard to imagine crossing them by wagon, much less by foot.
With the Homestead Act in the 1860s, however, 160 acres of federally administered land were given over to any qualifying individual (over age 21, not a Confederate soldier) who would "improve the land." In large part, this improvement — i.e. farming — saw the loss of as much as half of the northern grasslands.
Today, 98 percent of the tall grass historically present in the Northern Plains is gone. The loss is more than meets the eye -- because 90 percent of the prairie's biomass important root system lies underground, its contribution to the ecosystem largely goes unnoticed.
"The grasslands act as a natural water filtration system," said W. Carter Johnson, an ecologist at South Dakota State University in Brookings. "Without our having to pay for it, grasslands ecosystems provide hay for cattle, clean surface and ground water, organisms used for medicines, and plants for pharmaceuticals. If we just allowed nature to function, it would provide these for us without cost."
The first priority is simply stopping virgin sod prairies from being converted, Bauman says. But as he points out, its future largely depends on the few farmers and ranchers who value range land and grassland enough to protect it.
About 98 percent of the Buffalo Gap grassland acreage is grazed via permit; mainly by cattle and a small number of bison. But the Forest Service is also willing to acquire land adjoining grasslands directly from owners who are willing to sell. John Kinney, district Forest Service ranger for the Buffalo Gap National Grassland, notes that his district has picked up about 10,000 acres in the last decade.
However, convincing the farmer to switch from cultivation to grasslands for grazing or biofuel production (switchgrass is a favorite topic) comes down to economics. Less intensive uses are a tough sell, especially in tough times and especially when corn prices are setting records.
"If biofuels [from grasslands] present an opportunity, the Farmers' Union would like our members to take advantage of it," said Chris Studer, communications director for the 10,000-member South Dakota Farmers Union. "But at this point, I don't see that happening on a large commercial scale. Acre per acre, corn and soybeans are going to make more money."
However, in this age of climate change, grasslands also serve as important natural carbon sinks.
"Prairie soils are pretty rich in organic matter," Johnson said. "Once you cultivate it, you oxygenate it, turning it black. That organic matter decomposes to carbon dioxide and water. Land use change is always one of the factors that contribute to higher carbon dioxide levels and climate change."
Without the grasslands, Johnson says, there would be darker soils, more carbon dioxide in the atmosphere and slightly warmer temperatures.
"Ten years ago," Bauman said, "we'd say a parcel of land was unfarmable due to rocks or topography. But with large equipment that can roll across just about any landscape and drought- and pest-resistant seeds, the technology has advanced so that you can plant crops just about anywhere. Money talks, so [cultivation] is something that the conservation community has a very difficult time combating. Are we making progress? Yeah. Is it adequate? Probably not."