Grasslands are tough. They can survive extremes, from heatwaves and cold snaps to torrential downpours and droughts. They require turbulence. For millennia wildfires enhanced prairie soil and ensured grass’s dominance by burning back woody shrubs and saplings. Bison followed the fires to graze on tender, new growth of grasses and sedges; as they fed, their hooves aerated and manure fertilized the soil, giving rise to abundant wildflowers. The combined forces shaped the Great Plains, a mosaic of hundreds of grass, wildflower, and sedge species at various stages of growth spanning 550 million acres. The patchwork of habitats supports diverse insects, dozens of songbird species, and myriad mammals.
Despite their resilience, barely one-third of central North America’s historical grasslands persist today. Farming and development have razed 90 percent of its tallgrass prairie, three-quarters of its mixed prairie, and half of its shortgrass prairie. “It actually dwarfs what we’re seeing in the rainforest in the sheer scale and size and intensity of the crisis,” says Marshall Johnson, executive director of Audubon Dakota. That destruction has in turn hit grassland birds, which have declined by more than 40 percent since the 1960s; some species have seen even steeper declines.
Audubon’s North American Grasslands & Birds Report, published this summer, highlights the added perils that climate change poses to the Great Plains’ avian denizens. Heat, erratic rainfall, and drought may make significant areas inhospitable to certain species within decades. Audubon scientists built climate models that incorporate temperature, precipitation, vegetation, and other characteristics of the habitats 38 grassland-bird species occupy. They found that 16 species will likely see most of their current range become uninhabitable if Earth’s temperature rises by 3 degrees Celsius; if we limit warming to 1.5 degrees, the number facing this threat drops to just three.
The data also point to places, called “strongholds,” that will provide crucial habitat for grassland birds through the coming changes—if those lands are managed optimally. With more than 80 percent of U.S. grasslands privately owned, ranchers are key to protecting those critical areas. “Grazing is probably the most important tool for manipulating good grassland-bird habitat,” says Chris Wilson, director of Audubon’s Conservation Ranching Program. Across the Great Plains, conservationists are working with ranchers to shore up these strongholds and safeguard birds’ survival.
A New Take on an Old Tradition
For Cody and Deanna Sand, ranching is a tradition. When they took over Deanna’s family ranch in North Dakota in 1999, they observed practices inherited from their grandparents. They ran cattle across their 2,300 acres, bred cows in summer, fed them hay and grain in winter, and calved in frigid March. “That’s all we knew,” Cody says.
A decade later, the couple was tens of thousands of dollars in debt. They were determined not to sell to mega-farms, which would plow under the fertile mixed-grass prairie and its seasonal wetlands, or “potholes,” that supply plant and invertebrate food for breeding waterfowl, shorebirds, and grassland birds. Desperate, they took a course through the North Dakota Grazing Lands Coalition. The instructor offered a new perspective: Manage their grass, not their cows.
The Sands soon instituted rotational grazing: corralling one large herd through a series of small pastures, moving the animals before they overgraze to give grasses time to rest and recover. A $300,000 farm bill grant covered the up-front costs of fencing 64 paddocks and supplying water to each. After two years, the Sands had tripled their grass per acre, cultivating enough to graze cattle through the winter and eliminate the costs of supplemental grain. They also shifted their calving schedule to early summer, saving money on heaters, windbreaks, and veterinarians. Within a few years, their debts were paid.
Today native grasses, forbs, wildflowers, pollinators, spiders, dung beetles, and numerous birds flourish on their ranch, which has earned Audubon’s bird-friendly designation (see "Recipe for Success.") "I didn’t give two shits about a butterfly or a duck 10 years ago,” Cody says. Now he keeps an eye on three Sharp-tailed Grouse leks on the property, and Deanna is a budding birder.
Giant Grazers with an Immense Benefit
The first time Mark Sears visited Soapstone Prairie, he was only an hour north of Fort Collins, Colorado, but he could have sworn he was in the Serengeti. Grazing in the wide expanse of mixed prairie were herds of pronghorn, elk, and deer, which support predators like black bears and mountain lions. Prairie dogs guarded entrances to underground burrows, and the property had a complete suite of grassland birds, including Burrowing Owls, McCown’s Longspurs, and Lark Buntings (the state bird).
Soapstone Prairie’s 22,500 acres are also home to Lindenmeier, one of the nation’s most important archaeological digs. In the 1930s excavators uncovered a spear point embedded in a vertebra of Bison antiquus, a seven-foot-tall extinct ancestor of modern bison. The find offered definitive proof that humans inhabited North America 11,000 years ago—and earned the site designation as a national historic landmark.
As natural areas manager for Fort Collins, Sears’s job is to conserve land for wildlife first and public recreation second. So when Soapstone Prairie went up for sale in 2003, he moved fast: “We knew we had a once-in-a-lifetime opportunity.” Colorado is one of the fastest-growing states in the nation, which places its grassland patches on a crash course with development, especially near expanding cities like Fort Collins. He tapped conservation funds generated by county and city sales taxes, and drummed up additional dollars, to obtain the nearly $15 million needed to purchase the property in 2004.
Sears then took steps to make the grassland healthier. He instituted prescribed burns to replenish the soil and vegetation, for instance, and leased the land back to the previous owners, a grazing association, with the understanding that they would continue grazing sustainably and rotate herds and rest pastures more frequently.
If cattle aren’t moved regularly, they’ll chew grasses down to the ground and even extract the roots, killing the plants and eroding soil. Overgrazing ultimately upsets the complex ecology that builds rich soils, providing ample nutrients for diverse grasses, which then support insects and birds. It also eliminates the taller, denser patches of grass where birds nest and hide. And once overgrazed, prairie habitat is difficult, if not impossible, to fully restore.
The practice imitates the historical movements of bison, when enormous herds of hundreds of thousands of animals roved the Great Plains. They ate as they went, mowing the grass down to the sheath and fertilizing the soil. Then they moved on, sometimes not returning for many years, allowing grasses to recover and send up new shoots.
Fort Collins had been managing Soapstone for about a decade when Sears hit upon the idea of bringing bison back, to the delight of visitors. In November 2015 the city introduced one bull and a dozen or so cows related to the Yellowstone National Park herd, with a plan to manage them carefully to replicate their ancestral grazing behavior. Before releasing the animals, Sears’s team partnered with Colorado State University’s animal reproduction lab to ensure the animals were free of brucellosis, a bacterium that induces abortion and can infect cattle and people. It worked: “The bison herd is growing, perhaps a little faster than we had anticipated,” Sears says. Managers have tripled the pasture size to accommodate the 70 shaggy behemoths and may offer some to other bison restoration efforts.
As wild as Soapstone looked when Sears first saw it, it’s even more so now. Last summer Baird’s Sparrows—the grassland birds most vulnerable to climate change, according to Audubon’s report—were recorded nesting at Soapstone, a first for the state.
A Master Plan for a Shortgrass Prairie
In 2002 Nancy Ranney was working as an environmental designer and raising her family in California when she left that life to take the reins of her parents’ ranch in central New Mexico. She viewed the opportunity as a grand challenge: to manage the land more in line with the ecological principles she’d observed during her landscape-planning career.
Ranney took the ranch’s 21 herds, which each grazed continuously on its own pasture, and ultimately combined them into one that was frequently moved through 34 pastures of varying sizes. Melvin Johnson, the ranch’s longtime manager, was skeptical. “He was sure we’d be back to the old style in a couple of years,” Ranney says.
They weren’t. Within three years, Ranney Ranch’s blue grama grass monoculture had transformed into a mosaic of 35 different species of shortgrasses; these drought-tolerant varieties maintain 90 percent of their biomass beneath the surface. “There was seed bank in the ground that never had the opportunity to emerge before with constant, year-round grazing,” Ranney says. Today an estimated 50 grass species thrive, and the land supports nearly 300 cows and eight bulls. “No seeding, no fertilizing—just the cows,” she says. “We need them.”
A look across the fence line makes that clear. Some neighboring grasslands have not burned or been grazed for years. Whereas grass covers roughly 80 percent of Ranney’s pasture, the other land is barren or dominated by brush. Her property supports the rare Montezuma Quail, a secretive bird not usually found on a conventional ranch due to its need for dense grass cover.
Before Europeans colonized North America, wildfire burned across millions of acres, maintaining the dry shortgrass prairies of the Southwest. “These systems evolved under frequent fire and grazing,” says Jon Hayes, executive director of Audubon New Mexico. “We don’t see that anymore.” Settlements, roads, and fire suppression now limit natural blazes, which, like overgrazing and lack of grazing, prevent native grasses from regenerating. As a result, other types of plants overtake grassland habitat.
The encroaching vegetation—typically woody shrubs or invasive grasses—varies by region. Here, it’s mesquite, old-world bluestems, and lovegrasses. To the northeast, native juniper tends to invade undisturbed grassland. Farther north, in Colorado and Wyoming, the problem is cheatgrass. No matter the species, they have the same effect: “They crowd out the native grasses,” Hayes says, which drives out grassland birds like McCown’s Longspurs, Sprague’s Pipits, and Mountain Plovers that require sparse cover.
Energy development is another threat to the state’s remaining grasslands. In the southeast is the Permian Basin, now the world’s highest-producing oilfield. The infrastructure required to move that oil—well pads, roads, outbuildings, pipelines—transforms grassland habitat into an industrial zone inhospitable to birds.
Photos: Minesh Bacrania
Conserving this region’s extensive shortgrass prairie will be particularly important as the climate grows warmer and drier. Wet tallgrass prairies, like those in the eastern Great Plains, are projected to look more like mixed- and shortgrass prairies as their typical 40-50 inches of annual rainfall decreases, Hayes says, while the Southwest’s shortgrass prairies, which are accustomed to as little as 15 inches of rain annually, are more tolerant of drought. “Some of these places could be the last best place for some of these grassland birds,” he says, “because they’re already arid grasslands.”
The key is maintaining the right amount of grass; neither overgrazed bare soil nor undergrazed shrubland will support grassland birds. And as Ranney has proved, there’s a middle ground that benefits ranchers, too.
A Warm Welcome on Wintering Grounds
Arvind Panjabi had been conducting grassland-bird surveys in the Chihuahuan Desert for nearly a decade when he heard, in 2006, the first alarming reports: Field crews returning to study sites, most on ranches, discovered crop fields instead. “It happened multiple year