Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION VI.3.2. Southern Lake Michigan Lake Plain
DISCUSSION: Sub-subsection consists primarily of lacustrine deposits, but it also contains both fine-textured end and ground moraines that have been reworked by water. Along much of the Lake Michigan shoreline, there is a narrow band of steeply sloping sand dunes.
ELEVATION: 580 to 820 feet (177 to 250 m).
AREA: 1,356 square miles (3,511 sq km).
STATES: Michigan.
CLIMATE: See subsection.
BEDROCK GEOLOGY: The sub-subsection is entirely underlain by Paleozoic bedrock; Devonian shale occurs in the southern quarter; Mississippian shale, sandstone, dolomite, and gypsum occur farther to the north (Dorr and Eschman 1984, Milstein 1987). Overlying glacial drift is generally thick, from 50 to 350 feet (Akers 1938). There are very localized bedrock exposures of Coldwater shale in Ottawa County. Oil wells tap petroleum reservoirs in the underlying Devonian-age marine deposits (Dorr and Eschman 1984).
LANDFORMS: Sand dunes, up to 200 feet high, form a 1- to 3-mile-wide discontinuous band along the shore of Lake Michigan. The major period of dune formation was during Nipissing Great Lakes time, approximately 4,500 years ago; but smaller foredunes have formed during more recent times of low-water levels of Lake Michigan (Dorr and Eschman 1984).
Fine-textured end and ground moraines were concentrated in the southern half of the sub-subsection. Most of the moraines are flat to gently rolling.
In the northern half, there were extensive sand plains. Large deltas were associated with the Glacial Grand and Muskegon Rivers. Low dunes are common several miles inland; these dunes are associated with Glacial Great Lake shorelines as old as 16,000 years B.P. The topography of most of the lacustrine deposits is flat to gently rolling, gradually increasing in elevation from near the lakeshore.
LAKES AND STREAMS: There are a few small kettle lakes on the sand lake plain. The water level of many of these lakes fluctuates greatly, leaving them almost dry in some summers. These fluctuations result in a distinctive disjunct flora from the Atlantic and Gulf Coastal Plains along the lake margins. There are also a few small lakes on the moraines. Several of the larger rivers, including the Black, Kalamazoo, Grand, Muskegon, and White, have sand dunes where they meet Lake Michigan, creating small lakes behind the dunes. There are often extensive marshes within these shallow lakes.
SOILS: Soil textures range from sand to clay. Most surface lacustrine deposits are sand; those of the moraines are loams or clays.
Along the Muskegon River at the north edge of the sub-subsection, the lacustrine sands are generally excessively drained. A large part of these sands is outwash that contain few lenses of finetextured material to restrict drainage. Low dunes are locally common.
Poorly drained sands also characterize a large part of the northern half of the sub-subsection. Cemented B horizons are common. Finer textured subsoils are generally responsible for the poor drainage conditions. Small beach ridges and sand dunes on the poorly drained plain are excessively drained.
Soils on the upper and middle slopes of moraines are generally well or moderately well drained. On moraines, slopes of 6 to 12 percent are common. Poorly drained soils are restricted to drainage-ways and depressions in the moraines.
PRESETTLEMENT VEGETATION: In the southern part of the sub-subsection, forests were dominated by beech and sugar maple on both fine-textured moraines and sandy lacustrine deposits (Comer et al. 1993a). In the northern half, forests dominated by eastern hemlock and beech occupied most of the sand lake plain and fine-textured moraines.
In the south, white oak and black oak were common along the bluffs and broad ridges above major rivers, including the Galien, St. Joseph, and Paw Paw. Farther north, upland conifer forest dominated by white pine, along with white oak and some black oak, occupied the bluffs and broad ridges above the major rivers, including the Grand, Muskegon, and Kalamazoo, and also the sandy plains adjacent to White and Muskegon Lakes. Native American fire management may have maintained the white pine and oaks along the rivers.
The dunes supported forests dominated by eastern hemlock and beech. Hemlock-beech forest was the dominant forest type along the dunes of the entire shoreline as far south as Benton Harbor, near the southern edge of the sub-subsection. Although hemlock and beech were the dominant species, white pine, red oak, white oak, and sugar maple were also present. At the northern edge, white pine became increasingly dominant on the dunes, often with hemlock or white oak as co-dominants. Several large areas of open, blowing sand (blowouts) were noted in GLO surveys. These areas, generally less than a half mile wide, extended as much as a mile inland from the shoreline.
The largest wetlands were located along the rivers, where both extensive marshes and lowland hardwoods, often dominated by either black ash or silver maple, formed broad bands for several miles inland from Lake Michigan. Both tamarack swamp and lowland hardwoods swamp were located in bowl-shaped depressions behind the dunes.
Further inland, small kettle depressions within areas of end moraine supported small marshes and both lowland hardwoods and lowland conifers. Broad depressions on both the flat sand lake plain and the ground moraine contained emergent marshes, wet prairies, and both lowland hardwoods and lowland conifers.
NATURAL DISTURBANCE: The GLO survey found several blowouts in dunes. Although not noted by the surveyors, seasonal water level fluctuations occur on the lake plain, often resulting in dominance by either prairie or marsh species tolerant of such fluctuations. Such fluctuations can result in major cyclical changes in plant composition in shallow ponds or depressions as water levels change over a period of several years.
Native American land management with fire may have had a major impact on the vegetation in portions of the sub-subsection. There were local references by surveyors to burned lands along the Galien River and to Indian fields and trails along the Kalamazoo, Grand, and Muskegon Rivers.
PRESENT VEGETATION AND LAND USE: In the past, white pine and hemlock were harvested on the sand lake plain. Sand was mined on some of the dunes, primarily for use as molding and foundry sand. Most of the lands of the sub-subsection are in agriculture. Farming of the sand lake plain required large-scale drainage. Poorly drained portions of the lake plain now support nurseries and blueberry and asparagus farming. Better drained soils are converted to orchards and vineyards.
Some of the droughtiest and most poorly drained sandy soils remain as wildlife management areas or as recreational lands, either forested or wetland. Large portions of the coastal sand dunes are protected as park lands, but there is also heavy residential development of sections of the dunes.
RARE PLANT COMMUNITIES: The wet prairies of the sub-subsection are distinct from those found in other parts of the State and are called lakeplain wet and wet-mesic prairies. Many of the marshes, which occupy shallow depressions between beach ridges or sand spits (often several miles inland from the present lakeshore), are rich in disjunct species from the Atlantic and Gulf Coastal Plains of the U.S.
RARE PLANTS: Most of the rare plants are coastal plain disjuncts from the Atlantic and Gulf coasts; there are also species characteristic of the sand dunes of the Great Lakes. Carex platyphylla (broad-leaved sedge), Cirsium pitcheri (Pitcher's thistle), Echinodorus tenellus (dwarf burhead), Eleocharis melanocarpa (black-fruited spike-rush), Eleocharis tricostata (three-ribbed spike-rush), Hibiscus moscheutos (swamp rose-mallow), Juncus biflorus (two-flowered rush), Juncus scirpoides (scirpus-like rush), Lycopodium appressum (appressed bog clubmoss), Orobanche fasciculata (fascicled broom-rape), Panicum longifolium (long-leaved panic-grass), Potamogeton bicupulatus (waterthread pondweed), Pycnanthemum verticillatum (whorled mountain-mint), Rhexia mariana var. mariana (Maryland meadow-beauty), Rhexia virginica (meadow-beauty), Sabatia angularis (rose-pink), Scirpus hallii (Hall's bulrush), Scleria reticularis (netted nut-rush), Sisyrinchium atlanticum (Atlantic blue-eyed grass), Utricularia subulata (zigzag bladderwort).
RARE ANIMALS: Chlidonias niger (black tern), Clonophis kirtlandii (Kirtland's snake), Dendroica cerulea (cerulean warbler), Dendroica discolor (prairie warbler), Dendroica dominica (yellow-throated warbler), Hesperia ottoe (Ottoe skipper), Incisalia irus (frosted elfin), Lanius ludovicians (loggerhead shrike), Lycaeides melissa samuelis (Karner blue), Microtus ochrogaster (prairie vole).
NATURAL AREAS: State Natural Areas: Crooked Lake Marsh (Allegan State Game Area), Saugatuck; State Nature Study Areas: Warren Woods, Warren Dunes; Michigan Nature Association Preserves: Five Lakes, Wade Memorial, Barvicks Sand Dunes, Pepperidge Dunes, Beck Memorial; The Nature Conservancy Preserves: Grand Beach, Ross, Hofma, Robinson; Other: Sarrett Nature Center, Fernwood Nature Study Area.
PUBLIC LAND MANAGERS: State Game Areas: Grand Haven, Allegan, Muskegon; State Parks: Warren Dunes, Grand Mere, Van Buren, Saugatuck, P.J. Hoffmaster, Holland, Muskegon; National Forests: Manistee.
CONSERVATION CONCERNS: Sub-subsection VI.3.2 contains important tracts of sand dune
(as does Subsection IV.4, directly to the north), many of which are protected in dedicated natural areas or as State parks. Residential development, sand mining, and off-road vehicle use remain threats to these dunes. The coastal plain marshes contain some of the highest concentrations of species on Michigan's list of threatened and endangered species; these shallow wetlands are constantly under threat from residential development, dredging and flooding for game management, and off-road vehicle use. Allegan State Game Area, where several of these marshes are being protected, contains more of these marshes than any other area in the State. Allegan State Game Area also contains a large, viable population of federally threatened and endangered Karner blue butterfly; controlled burn management is being conducted to improve and expand habitat for the butterfly.
Disruption of coastal processes along the Lake Michigan shoreline, through creation of marinas and breakwaters, can destabilize other parts of the shoreline. The long-term effects of these processes have not been thoroughly evaluated, except where human lives and residences have been threatened.
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