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Dune and Swale Wetlands in the Sleeping Bear Dunes National Lakeshore
March 1, 1997 | By Hans Voss
Great Lakes Bulletin News Service
Dune and Swale Wetlands in the Sleeping Bear Dunes National Lakeshore
Freshwater dune and swale wetland types, a globally rare and unique resource, are found exclusively along Great Lakes shorelines. These wetlands are interspersed between sand dunes that were formed thousands of years ago when runoff from receding glaciers filled low-lying areas with fresh water.
The Sleeping Bear Dunes National Lakeshore boasts a 2,600-acre dune and swale complex near Platte Bay. An aerial view shows a series of arcs fanning out over two miles, generally following the contours of the existing shoreline.
Swales are dominated by open marsh, with grasses, sedge, and ferns. The Benzie County dune and swale wetlands sustain at least one bald eagle nest, and support four plant species that are on the state and federal "threatened" lists.
The public can explore the Park's dune and swale wetlands via Boekeloo Road, Peterson Road, and the Platte Plains hiking trail off M-22.
Platte River and Platte Lakes Wetlands
Wetlands are a chief reason for the clear water and excellent fish habitat of the upper Platte River. Mixed conifer and hardwood wetlands found along the length of the river and its tributaries protect the river from runoff and erosion.
As the Platte River approaches Big and Little Platte lakes the wetlands progress to a vast tamarack and cedar swamp. This type of wetland typically contains very wet, mucky, organic soils. Standing dead trees, known as snags, provide important habitat for small animals, insects, and birds such as bald eagles and owls.
Much of the Platte tamarack and cedar swamp is state-owned, and is reachable from Deadstream Road.
Herring Lakes Wetlands
In southwest Benzie County, there are 2,500 acres of beautiful wetlands surrounding Upper Herring Lake that are vital to maintaining the water quality of both Upper and Lower Herring lakes.
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Small Wetlands Are Also Important
Smaller, less recognized wetlands offer many of the same benefits as larger wetlands. They provide vital flood control; collect water and release it slowly into the ground to replenish aquifers; and provide important localized habitat for wildlife. The fact that many small wetlands are not always regulated by wetland laws does not diminish their importance.
State and Local Trends in Wetland Loss
Since Michigan was settled in the late 1700s more than 5.6 million acres of wetlands have disappeared. Fifty percent of the state's inland wetlands have been lost, and 70% of the coastal wetlands have been destroyed. This massive change to the landscape has caused increased flooding, water pollution, and diminished wildlife.
A significant amount of wetlands continue to disappear in Michigan, much of it allowed under state and federal law. Permitted fills for commercial and industrial development, housing, roads, agriculture, and logging claim an estimated 500 acres of wetlands statewide each year.
There are also losses from unpermitted wetland filling. It is difficult to determine the amount of wetland acreage that is ruined this way -- according to one conservative estimate, the loss in Michigan is roughly 500 acres annually.
The Michigan Land Use Institute estimates that Benzie County's portion of this overall wetlands loss is at least 3 acres per year. This figure was derived from the following information:
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