Superior's Arctic Enclaves

The north shore of Lake Superior harbors some unlikely denizens of the far north: arctic plants. Certain areas of lakeshore experience such a moderate cool-to-cold climate throughout the year that some plants can be found in small pockets far south of their normal range. Botanists call these plant communities "arctic-alpine disjuncts." This phenomenon is likeliest where topography juts into the lake, or on islands.

Two of the plants associated with this anomaly are butterwort and Hudson Bay eyebright. Butterwort (Pinguicula vulgaris) is a plant with a peculiar appetite, slowly absorbing nutrients from insects that are trapped by its sticky leaves. The plant endures the toughest conditions, rooting in rock crevices where storms occasionally polish the shore clean of most anything else. Hudson Bay eyebright (Euphrasia hudsoniana) is a member of a family of herbs once thought to cure 'all evils of the eye.' Euphrasia is still used as a homeopathic treatment for sinusitis--think of it as nature's Flonase.

In Minnesota, the Susie Islands shoreline, especially the Francis Lee Jaques Memorial Preserve, is a pristine example of this sort of habitat. The Susies are tucked beneath Pigeon Point, the easternmost tip of Minnesota's Arrowhead. The preserve is owned by the Nature Conservancy, which requires special permits to land on shore, but they're pretty tough to get to anyway. Two other examples are the Butterwort Cliffs SNA (Scientific and Natural Area) within Cascade River State Park near Grand Marais and Sugarloaf Point SNA near Little Marais, which served as a log-shipping site for years and was recently rehabilitated to restore its native plant communities. Both butterwort and eyebright are also found on Lighthouse Point in Two Harbors, a particularly accessible site for those hoping to view a botanical rarity.

Maybe the most drastic example of an arctic-alpine disjunct in the region is neither on the lake nor in Minnesota. Ontario's Ouimet Canyon, just beyond Thunder Bay, features rock walls so steep and high that they create a microclimate, and I have been told that ice sometimes endures year-round beneath the boulders and moss at the canyon bottom. Plants that are common throughout the region survive here only as stunted specimens. Visitors aren't allowed to journey to the canyon floor because of the unique and fragile plant community, but the view from the platforms leaning over the canyon walls is spectacular. You can see all the way down the canyon to the Sleeping Giant on Lake Superior. And my son Cole (Cole) can testify that the canyon produces a clear echo (echo).