A five minute drive, or - more commonly - a twelve minute bike ride from my house, Lake Michigan slices through the countryside and stretches west (on all but the clearest days) as far as the eye can see. The resulting shoreline draws tourists from all around the tristate area … but mostly from Chicago.
Families, windsurfers, and sun worshipers alike flock to packed beaches every weekend, enjoying the cohesive sand, freshwater, and ultraviolet radiation. Unknown to most, however, are the many parks, preserves, and sanctuaries a few miles south. The nearest of these - and the one that has consumed my weekends for about six months - is Grand Mere State Park.
In geologic time scales, Grand Mere is too young to seriously consider a newborn. It developed entirely within late human history.
The Great Lakes basins were carved by the receding Laurentide ice sheet beginning about 15,000 years before present. As the ice receded, it melted to fill the resulting troughs, and by 4000bp, the Great Lakes resembled their current configuration. (Interestingly enough, the entire area is still very young and dynamic. The land around the Great Lakes is still rebounding after the departure of the ice sheets, rising about 7.5 cm / century.)
The shoreline of western Michigan was - as it still is - highly irregular, with many jutting features and recesses. One such bay was at the present-day location of Grand Mere. Due to blowing sand from the beaches, longshore currents, and other possible factors, a sand bar began stretching across the bay, eventually fully enclosing the area and breaking the surface of the water. An ecological experiment, with as close to laboratory isolation as exists in the field, was beginning.
The land bridge shielded the inland lake from Lake Michigan, and vegetation and sand began to fill the basin, eventually creating an area of solid sand dunes with five small lakes.
This whole process created essentially a blank ecological palette, making Grand Mere a unique, ongoing experiment in ecological succession. Aquatically, development came through the process of eutrophication. As organisms established themselves in the sandy floors and shores of the inland lakes, they began cultivating proper soil and sediment. Over time, this and sand from the dunes accumulate, increasing the habitable area for other aquatic life while shrinking and shallowing the body of water.
Through this process, two of the lakes filled in and are now low-lying forested areas. The remaining three lakes are constantly becoming shallower and more densely populated. Around the edges, they blur with marshlands, and heavy brush and lily pads encroach on the water.
On land, Grand Mere is a perfect case study in ecological succession. One can walk from sand through brush to young growth forests, tracing time and ecosystems. The pioneer organism is the lowly Marram Grass.
This hardy, knee-height grass takes root in lose sand. It covers many of the dunes, forming a surface mesh which prevents erosion. The grass synthesizes various organic substances, and through the course of its life and death, it deposits nutrients into the ground. Slowly, the barren sand becomes a workable soil, hospitable to other organisms. Moving up the ladder of succession, you see shrubs and flowers, then small trees, and finally dense forests.
Grand Mere also contains a wide variety of microclimates, under the shelter of dunes or foliage. For instance, the south side of the park apparently hosts a well-developed hemlock forest, something usually seen much further north in colder climates. I haven’t been able to explore said forest, as the south side is extremely difficult to penetrate. I would love to explore it in greater depth, relying on GPS by necessity, but at this time of year the mosquitoes and other biting insects are far too pervasive.
Grand Mere also hosts some other species unusual to the area. It has significant quantities of prickly pear cacti, and some of these impostor plants pretending to be cacti. They still look quite sullen in the snow.
But, despite all the lovely plants and whatnot, my favorite part of Grand Mere is undoubtedly the beach. Now, it doesn’t look like this year round. In fact, it spends the majority of the year as yet another unremarkable beach, with sand and waves and whatnot, but every December the bitter cold and wind finally overpower the massive latent heat of Lake Michigan and ice begins forming.
Now, ice on Lake Michigan is completely unlike ice on a small pond or ice in the ocean. It is a chaotic series of equilibriums, with violent coups. The water around the shore is calm enough for uniform sheets of ice to form, but shifting winds and storms can bring in barrages of icebergs, floes, or other random objects, pulverizing whatever peaceful ice collection existed, then refreezing into a further jumbled mess.
My favorite time to visit is from February to March, when the ice begins melting. All the ice on the west and south coasts of the lake go first, and they’re swept all around, making for a glorious destruction derby as they collide with the thinning ice at Grand Mere.
It’s a fantastic time to walk around and take pictures, what with collapsing ice shelves and dripping icicles and the like. By that time of the year, the ice extends out for several hundred feet in a massive jumble of melded ice floes, cliffs, icebergs, meltwater streams, and caverns, and the water underneath is actually far deeper than it seems. What appears to still be solid sand is in fact merely sand embedded in a floating ice platform, and it’s impossible to tell what is solid, foot thick ice and what is about to yield all on its own, at least until you’re standing somewhere you thought safe and start hearing the ice fracturing all around you. That happens with disturbing regularity.
And, despite it all, I only fell in once.
