Sand Dune Ecosystem
JB: This is Earth and Sky. Around North America’s Great Lakes, glacial ice advanced and retreated between 13 and 18 thousand years ago.
DB: The ice ripped up rocks and ground them into sand. Waves eroded the sand and washed it to the shore of the Great Lakes. Wind blew the sand inland, forming vast dune fields.
JB: There’s still a lot of sand in the Great Lakes – so the dunes are still growing. And the winds keep the dunes undulating inland. For example, Michigan’s Green Mountain Dune has moved 30 meters – about 100 feet – in the past 200 years.
DB: The dunes also undergo change because of plants that grow on them. Marram grass catches blowing sand and forms small mounds that can build into large dunes with time. Grassy dunes support bird life – eagles, cranes, wrens and plovers. But the sand dune ecosystem is fragile. Dune buggies and even walking on the dunes tear out grass roots and leave bare piles of sand.
JB: Plus the car industry mines dunes for sand used in engine block castings. Even after passage of the Sand Dune Protection and Management Act in 1976, hundreds of acres of dunes have disappeared due to mining. Special thanks today to the U.S. Forest Service and to the National Fish and Wildlife Foundation – supporting the conservation of native fish, wildlife, plants and their habitats. We’re Block and Byrd for Earth and Sky.
The following individuals were interviewed for today’s show. Our thanks to:
Alan F. Arbogast
Associate Professor
Dept. of Geography
Michigan State University
Tanya Cabala
Michigan Director
Lake Michigan Federation
The following books, articles and web sites were used in preparing this script:
Additional Teacher Resources
Michigan Department of Environmental Quality, Sand Dunes.:“Protecting Michigan’s Sand Dunes”:http://www.michigan.gov/deq/0,1607,7-135-3311_4114—-,00.html
Michigan sand dunes are a resource of global significance; they are the
largest assemblage of fresh water dunes in the world. There are about 250,000 acres of sand dunes in Michigan of which about 70,000 acres are classified as critical sand dune formations. This site expounds on the significance of the Michigan dunes and also covers sand dune mining, and sand dune protection.
U.S. National Park Service, The Land and It’s Life: Our Fourth Shore; Great Lake Shoreline
This site provides a brief natural history of the Great Lakes shore line including the dunes, geology, flora, and fauna found within. It also provides photo images of flora and fauna as well as links to more information. This site is a good resource for students as an introduction to the natural processes that shaped the Great Lakes Region.
U.S. National Park Service, Geology Fieldnotes: Sleeping Bear Dunes
This 17 page report gives a detailed natural history of Sleeping Bear Dunes National Lakeshore, including park geology, soils, flora, fauna, detailed maps, photo images, teachers resources, and a variety of links to more geological information on the region.
