Walking the dunes of SW Michigan

Published 1:48 pm Thursday, April 29, 2010

From beach to wooded dune, Weko Beach has something for everyone. Photo by Terri Gordon

Off the Water

“Zee zee zee zu zee! Zee zee zu zee!” sings a black-throated green warbler. A dozen or so double-crested cormorants fly over in their distinctive formation – like a forked branch, unlike the formal “V” of geese. Spring is serious business for these birds. The warbler comes to nest in Berrien County; the cormorant feeds on alewives while migrating north to its breeding grounds.

The habitats nestled in the dunes along Lake Michigan’s shore house a multitude of species of birds and flowers, trees and grasses. Famed author and resident Carl Sandburg called the dunes “the Grand Canyon of the Midwest.” They are indeed a unique and rare occurrence.

Love Creek naturalist Pat Underwood often guides groups over the trails at Weko Beach in Bridgman. The routes meander through old, forested dunes, and out to newer, less vegetated dunes along the lake.

Two commonly found dune plants are sand cress and marram grass. Sand cress, a member of the mustard family, like many plants adapted to dry, sunny locations, has narrow leaves, which help it to conserve moisture. Marram grass is one of the first plants to grow on newly formed dunes. Underwood calls the grass a “dune builder” because its root network catches and holds the sand in place, allowing other plants to take hold and grow.

Dunes in southwest Michigan rarely form in straight lines. Instead, the wind blows them into a sort of horseshoe shape.

“The dunes in Berrien County, and a good share of the dunes along the coast of Michigan are what are called parabolic dunes,” explains Underwood. “The wind from the west blows in and gives this shape. It adds a lot of different habitats for plants and animals. Most sand movement happens in fall and winter when the vegetation is gone, because there is nothing to stop it. Over hundreds and hundreds of years, (new dunes formed, protecting the older back layer) and that gave things a chance to grow. There’s been hundreds of years for vegetation to grow here and – falling, decaying – turning what was sand into soil – very sandy soil, but soil nonetheless.”

Inner dunes tend to be wetter, cooler, and better established. Sand stays in place, held by plants, and plants grow because the sand is stationary. Beech and maple trees dominate the older dunes, while oak trees, preferring a drier environment, grow in the newer dunes.

North slopes sport white pine, and small “micro climates” appear throughout the folds, offering surprises – hemlock groves, wetland plants, and things that normally do not grow in southwest Michigan.

Spring is the best time to see wildflowers in bloom, keeping in mind they bloom a bit later along the lake than they do inland. Wild columbine, found primarily in wooded dunes. look like little orange ballerinas amongst the greenery. Dutchman’s breeches, white trillium, which turns pink when pollinated, and three kinds of Solomon’s seals pepper the forest floor. According to Underwood, starry Solomon’s seal is identified by its spray of little white star-shaped flowers, False Solomon’s seal sports a fuzzy plume, and “true” Solomon’s seal blossoms dangle. Other flowers include Long-spurred violets and Jack-in-the-pulpits. Dwarf ginseng and mayapples are also common. Mayapples with two “umbrellas” will harbor a flower, and eventually, an edible fruit (though the rest of the plant is poisonous). Mayapple with only a single umbrella will have neither flower, nor fruit.

On the open dunes, the sand cherry blooms, and the bright yellow of the hairy puccoon punctuates the sand.

Of course, the area is littered with critters – most of whom stay hidden – the redback salamander lays its eggs in rotten wood and the ant lion builds its copycat nests among anthills in hopes that other insects will slide into their holes and become trapped.

Along the beach, smooth round black stones and bits of crinoid stem can be found.

Basalt is of volcanic origin, smoothed and rounded in the waves of the lake. Crinoids are a commonly found fossil. Most of the rocks in Michigan originated in Canada and were deposited by the glaciers thousands of years ago.

Each season lends its own twist to dune hiking. By summer, wildflowers are gone, but trees are in full leaf, and offer respite from the sun. Fall is a good time for bird watching as many species follow the water’s edge in their migration routes. Winter allows folks to see the “skeletons” of the dunes and the trees, often highlighted by snowfall.

Folks don’t need a guide to enjoy the trails of the area’s dunes and beaches, they just need to get out and follow them.