By Nancy Sather
"The ancient Lake Ridge . . . forms a beautiful dry gravel road wherever traversed, and suffers only from the drawback of being the favourite haunt of numerous badgers, whose holes . . . are dangerous to horses; it is, apparently perfectly level for a hundred miles."
Henry Hind, 1857
My first introduction to geological history was on family excursions on state Highway 2 from my hometown of Fosston to Grand Forks. Just west of the village of Mentor, Daddy would announce, "We Are Now Crossing the Beaches of Lake Agassiz." We'd crane our necks for a lake or a beach. Disappointed, we'd barely file the place in memory. On that particular journey, we'd cross those imperceptible landmarks every three or four miles, each accompanied by an authoritative proclamation: Herman Beach. Norcross Beach. Tintah Beach. Campbell Beach. Each was a new source of frustration. Why could I not see something as simple as a beach?
Photo Gallery of Echoes of Oxcart Trails
In the 1950s, before they were pocked with gravel pits, the ancient beaches were hard to see. Their stairlike slopes into the Red River valley were almost imperceptible and Highway 2 cut across them at an angle.
Below each successive beach was a wet, level pasture. At the age of 14, concerned about food shortages half a world away, I'd demand why the level stretches hadn't been converted to wheat land. Daddy would respond that the old-timers knew the land was too wet and salty for crops. This unsuitability paid nature a bonus in the 1970s, when the Minnesota chapter of The Nature Conservancy and the Department of Natural Resources acquired and began to manage a large former cattle ranch as native prairie.
The beaches of Lake Agassiz, as I now know them, would scarcely be real without the memory of hot July days, skirting badger holes as I trek the beach on the east side of Crookston Prairie Scientific and Natural Area, dropping down its slope into the bed of the ancient lake, forging a path through the belt of aspen that advances into the prairie in years between prescribed fires. At the base of the slope, where calcium-rich water seeps out of the gravel ridge into low ground, knee-high stands of willow and shrubby cinquefoil obstruct easy walking. Where the shrubs finger out into the prairie, wet swales are bejeweled with western prairie-fringed orchid (Platanthera praeclara). I'm in an outlier of one of the world's largest populations of this spectacular plant. But it is declining, and so rare it's on the federal endangered species list.
I make that trip each year. Despite the rewards of watching the prairie's subtle responses to management, the sense of self-in-place that rises from knowing just where to anticipate the patch of scarlet gaura along the trail or when to forge off through the trackless brush, the purpose of the trek is "work." I'm here as a census-taker, paying a formal visit to those elegant orchids when they are in their best summer dress. In full flower, on a windy day, the white spikes are visible from a distance, standing rigid and erect in the waving grass. On a stem a foot to a foot and a half tall, their six to 12 pure white, ragged flowers approach an inch in length. Many years, my sister helps me pry into their private lives, plant by plant -- counting their flowers, measuring their heights, searching around in the cradles of wet sedge for their babies. Thus we know that a plant can flower for 10 years or more, with periods of dormancy in dry years. We've watched cohorts of slender, waxy first-year plants disappear altogether and had the privilege of seeing two seedlings persist and grow to flower at age 6.
We've seldom met another person in those swales or walking those ridges, and when we do, it's usually another biologist, checking on prairie chickens or monitoring songbirds. On Crookston Prairie, we can see the human evidence of the last century and a half on every horizon, farm buildings to the northwest, a railroad track to the south, fields to the north, and human-made, conical hills of gravel rising on the beach line to the east. But the ambience is one of the wild. Ticks and mosquitoes, sun, rain, and wind are just as inescapable as in a "wilderness." After an afternoon of bending and counting, stretching to the evening breeze, in former years sometimes watching a moose stalk across the prairie, we stretch to listen for a thin, high, trailing call on the ridge -- the quail-eeeeeee of the upland plover, a bird that 70 years ago had been hunted nearly to extinction.
For all the isolation one can feel today in the interbeach prairie preserves, were we to be counting orchids 150 years ago, it would be to the accompaniment of squeaking and groaning wheels, barking dogs, and calling voices on that very ridge. As we cut upslope we contemplate the possibility that this is the very "desolate prairie" on which the Hind exploring expedition met nine oxcarts Oct. 16, 1857. Perhaps it was from this ridge that they were "engulfed in a massive wall of smoke" that sunk the landscape "into a twilight gloom," alarming their horses. The knowledge that we follow the oxcart trail, if only for an eighth of a mile, imbues our annual pilgrimage with a sense of history.
We leave, sometimes thankfully, other times reluctantly, when storm clouds gather, or when the heat drives us out, or when descending dusk reminds us by casting a gold glow on the aspens on the eastern ridge and dropping the western prairies into gray shadows. On those rare occasions when dusk descends on our work, a sweet fragrance like honeysuckle rises around us. It's the orchids, bidding visits from their night pollinators. Were we to stay, and if we had black lights, which we don't, we might be blessed with the chance to watch a Sphingid moth uncoil its proboscis into the long nectar spur, carrying the little pollen sacs on its head as it moves from flower to flower. We gather our water bottles, our flags that mark the plants, our sampling frames that delimit the counting area, our backpacks full of mosquito dope and raincoats, and wander back. No need to retrace our steps. We know the way out. There are old wheel tracks on the ridge.