Forest, Fields, and Waters of Van Buren County

Natural Features>Natural Communities

Sand Dunes
Fens/Wetlands
Forests/Woodlands
Prairies

Sand Dunes

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Lake Michigan houses the largest concentration of freshwater sand dunes in the world.

Sand dunes were created in the last ice age, over thousands of year, and cannot be replaced once they are gone.

According to The Nature Conservancy, "the sand dunes of the Great Lakes support more unique species and communities than any other part of the Great Lakes system."

There are four distinctive types of dunes found in Michigan: parabolic, perched, linear and transverse.

Parabolic dunes are found in Van Buren County. These dunes occur in several large complexes along the eastern Lake Michigan shoreline. Ihe sand source for parabolic dunes is the broad sand terraces that formed along the lake margins 11,000 to 13,000 years ago. Parabolic dunes probably formed when the forested sand terraces were destabilized during high lake levelsn resulting in the formation of U-shaped blowouts. Dune destabilization occurred at intervals several hundred or thousand years apart, when lake levels were high. Strong winds result in migration of the dunes inland, while marram grass and other vegetation cause the sand to accumulate vertically. The end result is the formation of parabolic dunes 250 to 300 feet high.

Fens/Wetlands

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Prairie fens are geologically and biologically unique wetlands found only in the glaciated Midwest. In Michigan, prairie fens occur in the southern three to four tiers of counties. Currently, about 85 prairie fens are identified in Michigan totalling about 2,000 acres.

Prairie fens are found in the former oak-savanna prairie region of southern Lower Michigan. They are very rich in calcium and magnesium. Typical plants found in prairie fens are switchgrass, Indiangrass, big bluestem, sedges, rushes, Indian plantain, and prairie dropseed. The wettest part of a prairie fen, which is usually found near the water source, is called a "sedge flat" because members of the sedge family dominate the vegetation. The "fen meadow" is the largest part and is more diverse with many lowland prairie grasses and wildflowers. Slightly elevated areas, especially around the upland edge, also support tamarack, dogwood, bog birch, and poison sumac.

Related Links:
MNFI abstracts - prairie fens

Forests/Woodlands

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In the early 1800s, forests covered most of Michigan's more than 36 million acres of land. Today, nearly all of the state's landscape has been disturbed by human activity. This disturbance has decreased our forests by 50 percent. A long period of heavy logging and fires, which began about 1840 and ended about 1930, substantially contributed to this loss. Currently, the largest threat to our remaining forests is fragmentation , which occurs when larger properties are divided into smaller parcels. Also, the lack of old growth forests, which provides structural diversity, is a threat to our landscape ecosystems . Current logging practices favor certain tree species over others causing forests to become ?over simplified? and altering natural processes. Other threats to Michigan forests include over browsing by deer, hydrologic alterations, and the timber harvesting process of ?high grading? which is a profit motivated technique that has no value for wildlife.

Michigan's more than 19.3 million acres of forest provide ecological, economic, recreational, and aesthetic benefits to the state's citizens. One of Michigan's important natural resources, these forests range in size from small, privately owned woodlots to larger areas owned by the public, industry, or timber companies. Trees help to hold the soil in place and prevent erosion . They remove carbon dioxide from the air and replace it with oxygen, furnish shade, and help cool rivers and streams. In addition, they furnish homes, food, and shelter for wildlife and provide wood for the production of lumber, paper, and various other products

Prairies

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Grasslands are areas often referred to as prairies or meadows, consisting primarily of grasses with associated wildflowers. These areas provide essential habitat for many species of wildlife . Presently, Michigan has only small remnant prairies scattered across the state. At the time of Michigan's settlement, there were approximately 2.35 million acres of grasslands. Historically ranging from several to thousands of acres, grasslands have drastically declined because they have been converted to agricultural fields or lost because of fire suppression.

Although we have lost almost all of our native prairies, Michigan still has some grassland areas. Non-native cool season grasses have been planted along roadsides, as hayfields and pastures, and often establish themselves in the fields retired from farming. These fields can provide important wildlife food and cover.

Within grasslands, a variety of wildlife such as pheasants, wild turkeys, songbirds , foxes, hawks, raccoons, and sandhill cranes eat abundant insects, seeds, and small rodents that grasslands produce. Also, mice, voles, shrews, woodchucks, and many kinds of ground-nesting birds raise their young there. The size of the grassland plays a significant role in attracting certain species of wildlife. Small grasslands one to five acres in size are activity zones for deer and rabbits. Other wildlife species, such as bobolinks and meadowlarks, may require 20 or more acres of grassland to survive.

Pure prairies are ecosystems that are relatively free from the invasion of shrubs and trees. They occur where sites are too wet or too dry for woody vegetation to grow, or where plant succession has been checked through fire. If you have a prairie on your property, chances are it will be a prairie remnant that is degraded, but that might be restored. Doing some detective work at the local library and the county Conservation District office may turn up clues such as historical photos. Talking to neighbors and former owners may yield more information. Armed with a good identification guide of native grasses and wildflowers, you might be able to identify remnant prairie plants. Or perhaps a local expert will walk your property with you and help with identification.

If you have a former prairie and want to restore it, you may need to remove shrubs and trees, by mowing, burning or herbicide use. In some cases you may be able to interseed the site, preferably with seed from native plants from the immediate area or begin a new planting altogether.

Excessive weed growth is the biggest hurdle to establishing a lush grassland that has maximum benefit to wildlife. Native grass plantings in particular may take three to five years to dominate the site, especially if weeds were not controlled during the first year after planting. During that first year of life, native grasses grow mostly below the ground as their root systems develop. Because little growth appears above ground where weeds are likely rampant, many landowners become needlessly discouraged. Once the stand is established, though, periodic burning will keep it healthy. Other methods to maintaining grasslands include strip mowing in alternating years, light grazing by livestock, and spot treatment of problem weeds or invading shrubs with a selective herbicide.

Page Last Updated: 7/15/2003