A sun-drenched desert stretched across 1,200 acres. Prickly pear, its flat-stemmed flesh blooming with red fruit. Butterfly weed and prairie violet providing pops of color amidst the needlegrass and little bluestem. Hognose snakes and six-lined racerunner lizards skittering across the sandy soil. Black oak barrens, beyond the 60-mile stretch of golden bluffs, overlooking the prairie and the Wisconsin River.
Although its very existence is almost unbelievable, its origin story is ancient history. “Thousands of years ago, the Wisconsin River was much bigger,” explains Hannah Spaul, director of land management for the Nature Conservancy’s Wisconsin chapter, which has managed the preserve since 1971. “During the ice age eight to 10 thousand years ago, massive lakes and rivers drained into Wisconsin. The Spring Green Preserve is the remnant of where the river used to be.” The bluffs chart the course of the original waterway, separating the sun-kissed dryland to the south and the lush woodlands to the north.
But how can a desert survive in the same state where Lambeau roars with a snowy football game? Simply put: subtle resilience. Plants are desert actresses. They appear to die, but their roots live on and await a springtime awakening. Snakes, meanwhile, are underground sleepers. And birds are migratory nomads that always return.
In fact, the preserve offers one of Wisconsin’s first signs of spring. “It’s one of the only places in the state we have a prescribed fire in January,” Spaul explains, “so that the habitat stays healthy from invasive species like honeysuckle and red cedar.”
Hundreds of years ago, fires of this nature kept the grassland intact across much of the state. “Prior to European settlement, 10 million acres of Wisconsin burned each year, often set by Native Americans to intentionally manage the land,” notes Spaul. “Fire was an ecological driver across most of North America. It maintained the grassland landscape because it stopped trees and shrubs from becoming established.”
But all that changed when much of Wisconsin’s land was converted for agricultural use. Today, less than one-tenth of 1% of the state’s original native grassland remains. That’s why the Spring Green Preserve is so special; it’s one of the rarest habitats on the planet.
And the desert itself is a visual representation of the land’s evolution over time. “I like to see where the desert transitions from one habitat to another,” Spaul says. “You can see such an essence of history and today over the Lower Wisconsin Riverway.”
Want to experience this natural wonder for yourself? Spaul recommends visiting in May or June, when everything is in bloom. Wear sunscreen and stay on the path. The rarity of this desert can be safely preserved if we continue to look upon it in awe.