Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION VIII.1.2. Rudyard
DISCUSSION: This small sub-subsection of lake plain with fine-texture soils has been more intensively managed for agriculture than any other part of Upper Michigan.
ELEVATION: 580 to 800 feet (177 to 244 m).
AREA: 666 square miles (1,725 sq km).
STATES: Michigan.
CLIMATE: Average growing season ranges from 120 days in the north to 140 days in the south (Eichenlaub et al. 1990). Extreme minimum temperature ranges from -32½F over most of the sub-subsection to -38½F in the north and northeast along the St. Marys River. Average annual precipitation is 32 to 34 inches. Annual snowfall ranges from 120 inches in the north (lake-effect snows) to 80 inches in the south.
BEDROCK GEOLOGY: Sub-subsection is underlain by Silurian- and Ordovician-age sedimentary bedrock, principally limestone and dolomite, capped with lacustrine clays. The underlying bedrock is typically less than 50 feet below the surface of the lake clays for much of the sub-subsection, but is 100 to 200 feet thick where preglacial valleys dissected the bedrock surface; such valleys underlie the present valleys of the Pine and Carp Rivers (Vanlier and Deutsch 1958; Sinclair 1959, 1960).
LANDFORMS: Almost the entire sub-subsection is a broad clay lake plain. A small area of sand lake plain is present in the center of the sub-subsection. Within this small area of sand plain, there is a series of ancient beach ridges and swales, many miles from the present Great Lakes shorelines.
Sandy ground moraine occurs on Sugar and Neebish Islands and on the mainland at the north end of Munuscong Bay.
LAKES AND STREAMS: No lakes. Several rivers, including the Carp, Pine, Waiska, Little Munuscong, and Munuscong, cut deep, narrow valleys across the lake plain.
SOILS: The clay soils are somewhat poorly drained to poorly drained. The flat lake bed becomes more poorly drained closer to the St. Marys River along the eastern edge of the sub-subsection. Soils are generally well drained on the ground moraine of Sugar and Neebish Islands.
PRESETTLEMENT VEGETATION: Somewhat poorly drained to poorly drained clay soils originally supported a hardwood-conifer forest of balsam fir, balsam poplar, hemlock, northern white-cedar, tamarack, trembling aspen, white pine, black spruce, and white spruce (Comer et al. 1993a). Northern hardwoods, including sugar maple, beech, American elm, basswood, and yellow birch, were locally common on slightly better drained sites. The extensive poorly drained areas along the St. Marys River were primarily dominated by conifers; large peatlands near Munuscong Bay and Izaak Walton Bay on the St. Marys River were dominated by cedar, spruce, and tamarack.
The poorly drained shorelines of the clay plain support some of the most extensive marshes of Michigan. The emergent marsh zone can be a mile wide, and the wet meadow zone along the shoreline is often another quarter- to half-mile wide.
The sandy ground moraine of Sugar and Neebish Islands supported northern hardwood forests of beech and sugar maple. Poorly drained portions of these ground moraines supported speckled alder-willow swamps.
NATURAL DISTURBANCE: Poor drainage conditions cause widespread windthrow. GLO surveyors noted large windthrows south and west of Sault St. Marie and on the south side of Sugar Island.
PRESENT VEGETATION AND LAND USE: Europeans had already settled at Sault St. Marie when the area was surveyed in 1845. Forests had been cleared for several miles around the settlement. Native American settlements and trails were also present.
In subsequent development, forests were cleared and swamps were drained extensively for agriculture. Swamps near the Great Lakes shoreline have been modified less than those elsewhere in the sub-subsection. Many emergent marshes along the St. Marys River were hayed for marsh hay by creating shallow ditches in the marsh. All these ditches have now been abandoned. A large part of the marsh at the mouth of the Munuscong River has been diked for waterfowl management.
RARE PLANT COMMUNITIES: None identified to date.
RARE PLANTS: Ranunculus lapponicus (Lapland buttercup).
RARE ANIMALS: Alces alces (moose), Chlidonias niger (black tern), Sterna hirundo (common tern).
NATURAL AREAS: Michigan Nature Association Preserves: Beaver Dam, Lapland Buttercup, Three Wilderness Islands, Carlton Lake Wetlands, Roach Point; Other: Osborn Preserve.
PUBLIC LAND MANAGERS: Michigan: National Forests: Hiawatha; State Forests: Lake Superior; Environmental Areas: Frog Bay, Roach Point, Pickford, Shingle Bay, Kemps, Rock Island, Duck Lake, Muskrat, Neebish, Gogomain, Hiawatha, Sand Island, Birch Point, Winter, Round Island (Chippewa County), Gem Island, Dike.
CONSERVATION CONCERNS: The wetlands along the St. Marys River are extremely important for waterfowl migration.
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