The Sandhills are the Great Plains’ largest and most unspoiled grassland ecosystem. Spared from the settlers’ plow by steep dunes, nutrient-poor soils, and a semiarid climate, this sea of grass stretches from horizon to horizon, the rolling dunes broken only occasionally by interdunal lakes, marshes, and meadows. One can drive for miles and see no signs of humanity except for barbed wire fences, windmills, grazing cattle, and a lonesome ranch house.
One might think this extensive Sandhills prairie is an ancient stable ecosystem, but the opposite is true. A mere fourteen thousand years ago, as the last Ice Age was releasing its frozen grip on the continent, the dunes were covered by northern grasslands and spruce and aspen woodlands and roamed by mammoths and other Ice Age animals. During the following millennia as the postglacial climate warmed, spruce and aspen retreated northward in the glacier’s shadow, and the warm-season grasses and forbs characteristic of today’s grasslands expanded to fill the void. Then, about ninety-five hundred years ago and for much of the next several thousand years, severe, long-duration droughts, called mega-droughts, frequently descended upon the plains, withering the dune’s protective grass cover while winds set the sand to blowing. Sahara-like naked dunes slowly rolled across the land. Remarkably, some bison survived in the Sandhills during this interval of frequent droughts, likely by grazing in the still green, groundwater-fed valleys. Proof is found in the hoof prints they left in the blowing sand, which are visible today in cutbanks as pockmarks in the laminated sands.
Eventually rains returned, and grass stabilized the dunes, but mega-drought lurked in the shadows, again showing its face about 950 years ago, when several hundred years of frequent drought set the dune tops to blowing. In the late 1700s and early 1800s, the first Euro-American explorers traversed the region during an era of dryness, wildfires, and large bison herds. The dunes were stable, but grass cover was sparse, with much open sand between plants. The explorers struggled crossing the dunes on horseback and despised the Sandhills. J.H. Snowden of the 1857 Warren expedition lamented, “Much broken by and cut by winds, supporting a very scant vegetation . . . Our greatest wish is to be away from it [the Sandhills] as soon as possible and never return.” They deemed the region not fit for man nor beast.
Cattlemen ignored that scathing report and in the 1870s began drifting into the Sandhills, finding the dune and meadow grasses splendid for fattening herds for eastern markets. The news spread, and more ranchers followed. Passage of the 1904 Kinkaid Act, which gave settlers 640 acres of free land, brought a minor rush of farmers to the region. The Kinkaiders scraped by, farming hardscrabble flats and dry valleys but lasted, at most, a few decades before vacating their claims. In all, they plowed perhaps 10 percent of the Sandhills prairie, which eventually reclaimed the abandoned fields.
Although the Sandhills remain rangeland, settlement brought ecological changes, primarily through wildfire control and replacement of roving bison with fenced cattle. These factors, along with a wetter climate in the early 1900s, led to denser grass cover on the dunes and less exposed sand. Thick grass benefited cattle but crowded out wildflowers. The once common blowout penstemon, which grows in open sand, now struggles to survive, with only a few thousand plants remaining. Compounding this issue in recent decades is a shift from season-long cattle grazing of large pastures to rotational grazing of smaller pastures, which has resulted in more uniform grazing and consistent grass cover. Grazing-sensitive wildflowers have declined, including the shrub, New Jersey tea, which is now mostly found in un-grazed road right-of-ways.
Today, abundant dune grasses include needle-and-thread, prairie sandreed, sand bluestem, little bluestem, and sand lovegrass. Less abundant are an array of wildflowers and other grasses, along with a few sedges and shrubs. The exact number of plants inhabiting Sandhills prairie is unknown, but a 2006 survey of the seventy-thousand-acre Valentine National Wildlife Refuge in Cherry County found 175 native and a few non-native species growing on the dunes, the latter arriving since settlement. Many of the native species, such as sand dropseed, lemon scurf pea, and bird’s-egg milkvetch grow only in sand, while others, such as side oats grama and prairie rose, grow in other soil and prairie types.
In late March, sun sedge is the first dune plant to awaken from winter slumber. This short grasslike plant is sought out by grazers, a nutritious bite of green in the still winter-brown prairie. Spurred by spring rains and warming days, wildflowers soon follow into bloom. Among those splashing the hills with spring color are the pink to purple-red to blue pealike flowers of hoary vetchling, the bright blue blooms of spiderwort, the fluorescent yellowish-orange blossoms of hairy puccoon, and the spikes of purple locoweed. The latter’s name reflects the fact that if eaten by livestock it can become addictive, and if consumed in abundance, causes animals, particularly horses, to become spooked and disoriented.
Among the Sandhills’ spring bloomers are its only tall shrubs: American plum and chokecherry. Cloaked in white blossoms, they appear snowball-like among the greening dunes. Their flowers’ sweet scent draws crowds of bees, butterflies, and other pollinators, while their summer-ripening fruit attracts wildlife and jelly-makers alike. The shrubs often form thickets on cool, north-facing slopes and moist pockets in high dunes, providing relieving summer shade for prairie grouse and deer.
With a rosette of bayonet-like leaves and a tall spike of spring-blooming white flowers, yucca is the quintessential dune shrub. Cattle relish its tender blooms and young seedpods, which rarely mature in spring- and early-summer-grazed pastures. Cattle and bison prefer to graze the evergreen leaves in winter, when it is the only green available.
When summer’s heat settles on the dunes, a new flush of wildflowers come into bloom. Common perennial species include sand milkweed, prickly poppy, hairy golden aster, and silky purple-and-white prairie clover. Perhaps most abundant is fourpoint evening primrose, a biennial that brightens roadsides and other disturbed sites with large spikes of yellow blooms. Midsummer is when most prairie grasses send forth their sun-harvesting leaves and flowers. The nourishing leaves fuel the region’s beef industry, while the flowers mature into seeds that cater to birds and small mammals.
Late summer brings on the asters, goldenrods, and sunflowers. Annual sunflower, like fourpoint evening primrose, thrives under disturbance and, in years of plentiful rain, can turn hard-grazed pastures yellow with blooms. The flowers often linger into early fall, mixing with the now frost-hued vibrant purples, oranges, and tans of the prairie grass. The Sandhills’ autumn colors rival those of eastern forests.
Change, whether throughout seasons, decades, or millennia, typifies the Sandhills prairie, and if the past foretells the future, human-induced climate change will also alter the prairie. Already, recent mild winters and longer and wetter springs appear to be favoring the spring-growing, non-native grasses, like smooth brome and Kentucky bluegrass. In some areas they are marching out of wet valleys onto lower dunes slopes, displacing native plants. Will this climate pattern continue and allow these grasses to creep farther up and over the dunes? Perhaps climate change will induce hotter and drier summers and set the dunes to blowing. A worst-case scenario would have slowly advancing, unstoppable dunes burying fences, highways, and other signs of settlement, in a sense, rewilding the land. At present, science can only guess what the future holds for the Sandhills.
What is known is that the Sandhills prairie is the pride of Great Plains grasslands—scenic, diverse grazing lands to be cherished and conserved for future generations.
Gerry Steinauer is a botanist-ecologist for Nebraska Game and