History Gem – Sand Dunes: A Fragile Ecosystem

As I looked through the Gitche Gumee Museum’s archives, I came across an article about sand dunes, titled” Dunes: As fragile as the shifting sands, we all need to protect this unique resource.”  It was published Michigan Natural Resources magazine in May/June 1979.  As much as I love the Lake Superior beach, I must admit my favorite place in Grand Marais is the Grand Sable Dunes.

Grand Sable Dunes is approximately five square miles of rugged terrain.  The dunes intersect the Lake Superior shoreline with the Grand Sable Banks.  These banks are 300 feet above the lake, but there are sections in the dunes that are more than 400 feet higher than the bluff of the banks.

These dunes formed after the glaciers retreated around 10,000 years ago.  One of the post-glacial lakes prior to the current Lake Superior was Lake Nipissing.  The water level of Lake Nipissing rose, which caused the Grand Sable Banks to become unstable and erode. A dominant northwesterly wind blew and carried the sand from the bluff to pile up in the flat upland south of the Grand Sable Banks. This sand was “perched” on top of the upland, hence the name, “perched dune system.”

Information from the Michigan Natural Resources magazine is below.

“Dunes have wide appeal.  as direct evidence of the Ice age, dunes are of considerable interest to geologists.  Botanists and biologists also are fascinated by the surprising diversity and distribution of plant and animal species found in the dunes, and by the unique adaptations these life forms make to high temperatures and low moisture conditions.”

“With all these values inherent in our dunes, it’s obviously important that we take steps to preserve them.  The climatic and geologic conditions that created them no longer exist, so if the dunes are destroyed, they are not likely to ever regain their present size and extent.”

It is because of the fragile nature of the dunes that the Pictured Rocks National Lakeshore does not allow any type of motorized vehicle in the area.  Most people respect this rule and do not drive their snowmobiles or four-wheelers up into the dunes.  If you should get caught, there are steep fines and the possibility of having your machine confiscated.  The amount of damage caused by violators is beyond what they can imagine.  The photo below shows a broken tree caused by a snowmobile.  There were more broken trees than we could count

So if you are in the Grand Marais area and decide to trek up into the dunes, please be respectful of this beautiful and fragile ecosystem.




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