Natural Areas and Native and Exotic Species
The Extraordinary Natural Habitats of Northwest Indiana
The extraordinary diversity of the flora and fauna in the Lake Michigan coastal area is a result of several
natural processes that have contributed to the formation of the shoreline. As the glacial ice retreated
about 12,000 years ago, fluctuating lake levels in combination with wind and wave actions contributed to
the formation of the physiography of the coastal area and influenced the distribution of the plant and
animal species. Habitat formation resulted from the development of the Calumet Lacustrine Plain, the
Valparaiso Morainal Area, and the stabilization of these areas by vegetation. The species diversity and
complexity of the initial stabilizing plant communities changed with time, subsequently resulting in a
series of habitat types ranging from bare sand to forest, and from open water to marsh.1
Interdunal Ponds at the Indiana Dunes National Lakeshore
Wetlands are numerous behind the backdunes and throughout the Calumet Lacustrine Plain. The majority of the wetlands were found during an inventory in 1976 to be present in the Indiana Dunes National Lakeshore and the Indiana Dunes State Park. There are site specific plants and animals that would perish without wetland habitats. Pitcher, sundew plants, and wild orchids are a few examples of plants dependent on wetlands. Animals dependent on wetland habitat include furbearers, marsh hawk, least common bittern, flycatchers, and herons.
Pitcher's Thistle and Black Tern
The Valparaiso Morainal Area, just south of the Calumet Lacustrine Plain, still contains forest areas although most of this area has been developed for urban or agricultural use. Forests include red oak, white oak, red maple, basswood, wild black cherry, white ash, and bluebeech. Forest types vary with exposure, soil type, nutrient, and soil availability.
Dune and Swale
Twenty-six percent of plants considered endangered or threatened in Indiana are found at the dunes; many of those plants are thriving here at the edges of their natural ranges. Other species are relics from glacial periods that are totally isolated from other populations of their kind.
Examples include two North Wood trees, the white cedar and the jack pine. Other northern plants surviving
here include trailing arbutus and bearberry. Sea rocket and marram grass are usually found in the
Atlantic coastal plain. Other species found near the shore are characteristic of the Appalachians such
as the tulip tree and sassafras. Many of these species have adapted to their "new" habitats through
changes. For example, leaves of the prickly pear cactus have all but vanished, a characteristic useful on
sunny slopes of dunes. The bearberry's habit of growing in low, flat, clumps enables it to survive the
harsh cold of northern winters as well as the winds blowing over the dunes. Species only found on the
shores of Great Lakes also thrive here.
These plants include silver-foliaged sand thistle and the glowing Kalm's St. Johnswort.5 The reptile and
amphibian species not likely to occur outside the region include the western painted turtle, six-lined
race runner, plains garter snake, western ribbon snake, and the western smooth green snake.