|Photo by Bobbie Harte, HarteVentures LLC|
While the majority of the Driftless region is in western Wisconsin, it also extends into parts of Minnesota, Iowa and Illinois. Why is it called “Driftless”? Retreating glaciers leave behind silt, clay, sand, gravel and boulders, which is generally called drift. During the last glacial period, which ended some 12,000 years ago, ice did not cover this area. It is drift-less.
During the last two million years, glaciers up to two miles thick sculpted about one-third of the earth’s topography, creating North American landmarks such as the Great Lakes, Niagara Falls, the Kettle Moraine and the Ohio River. The Driftless was never an island surrounded by ice, but over the course of time different glacial lobes moved around it. The deep fold in the bedrock at Lake Superior (known as a syncline) siphoned ice from Canada to the southwest. Weak rock created lowlands that were easily scoured by glaciers, acting like a funnel to draw ice to the southeast. Structurally, Wisconsin is an arch from east to west, with friction of rocks causing resistance to northern glacial advancement. All of these factors played a part in drawing ice away from the Driftless region, preserving this ancient landscape of sandstone bluffs and deeply-carved river valleys; of sinkholes and cave systems; of underground rivers and above-ground springs; of rock shelters and effigy mounds; of Ice Age relict animal and plant communities like snails, rattlesnakes and Northern Blue Monkshood; of algific talus slopes and goat prairies.
|Photo by Bobbie Harte, Harte Ventures LLC|
Goat prairies have sparked my curiosity in two main ways. First, the plants themselves are fascinating. With the help of a specialist from the Wisconsin Department of Natural Resources, Jim has identified more than 250 native plant species on his property alone, and each one has a story. Take Leadplant, for example. This native woody shrub can live for centuries, although it never grows past a height of three feet. Leadplant is also sometimes called Prairie Shoestring because of its large and complex root system, which grows as far as ten feet deep. Deep roots make this and other native plants uniquely suited to such rocky terrain. They are able to withstand dry summers, prevent erosion and maintain the fertility of the soil.
The second way goat prairies have sparked my curiosity has to do with the effect that human habitation has had on the landscape. In 2003, Gerald W. Williams wrote a paper for the USDA Forest Service entitled “References on the American Indian Use of Fire in Ecosystems.” Williams writes that American Indians modified the ecosystem, largely through the use of fire and for a variety of reasons: to make hunting easier; to improve grass grazing for deer, elk, antelope and bison; to deprive enemies of hiding places; to improve the fertility of the soil; and pest management. This is a topic I would like to explore further. I suspect we can learn much from the practices of past human cultures and use them as an example for our own interactions with the landscape.
Partly to catch our breath and partly to appreciate the view, Jim and I paused at the top of the goat prairie, looking over the distance to other bluffs and other valleys. I tried to comprehend it all: the variety of animal and plant life around me; roots plunging six, ten, fifteen feet into the earth; the course of the twisting Bad Axe River. I tried to comprehend living as a hunter-gatherer who built effigy mounds in the shapes of bears or birds. I tried to comprehend a different sense of time, one not based on hours or days or even a human lifespan, but encompassing thousands and millions of years.