Types of Wetlands
Aquatic Bed
Areas of shallow permanent water that are dominated by plants that grow on or below the surface of the water.
Great Lakes Coastal Wetland
The hydrology of these wetlands is driven by Great Lakes water level fluctuations. There are different types of these rare wetlands due to substrate (clay, sand, muck) and exposure to wind and wave action.
Barrier-beach Wetland
A barrier beach wetland is formed when nearshore currents deposit a sand or gravel barrier bar across the mouth of an embayment. These wetlands form behind the sand barrier. The resulting shallow pond or lagoon is sheltered from the lake's wave energy; sediments accumulate in the lagoon basin and vegetation can become rooted. Although water levels in the lagoon may be augmented by tributary streams and groundwater seepage, coastal lagoon wetlands are also partially controlled by the Great Lakes, through permanent or intermittent connecting channels, wave overwash, or cross-bar seepage.
Areas of shallow permanent water that are dominated by plants that grow on or below the surface of the water.
Great Lakes Coastal Wetland
The hydrology of these wetlands is driven by Great Lakes water level fluctuations. There are different types of these rare wetlands due to substrate (clay, sand, muck) and exposure to wind and wave action.
Barrier-beach Wetland
A barrier beach wetland is formed when nearshore currents deposit a sand or gravel barrier bar across the mouth of an embayment. These wetlands form behind the sand barrier. The resulting shallow pond or lagoon is sheltered from the lake's wave energy; sediments accumulate in the lagoon basin and vegetation can become rooted. Although water levels in the lagoon may be augmented by tributary streams and groundwater seepage, coastal lagoon wetlands are also partially controlled by the Great Lakes, through permanent or intermittent connecting channels, wave overwash, or cross-bar seepage.
Protected Embayment
Many stretches of bedrock or till derived shorelines form small protected bays, typically less than three or four kilometers in width. These bays can be completely vegetated with emergent or submergent vegetation. Examples include Duck Bay and Mackinac Bay in the Les Cheneaux Islands on Lake Huron, Matchedash Bay on Lake Huron, and Bayfield Bay on Wolfe Island in Lake Ontario.
Tombolo
An island connected to the mainland by a beach ridge or series of beach ridges. Enclosed lagoons can contain dense growth of aquatic vegetation, and there is occasionally a fringe of emergent vegetation outside of the tombolo.
Interdunal Swale Wetland
A wetland dominated by grass-like vegetation that occurs in the low areas between sand dunes or beach ridges along the Great Lakes shoreline. These wetlands depend on the Great Lakes for their water source. As such, their water table and period of saturation fluctuates with Great Lakes water levels. Because of the highly variable ecosystem characteristics, and the fact that they exist nowhere else on earth, interdunal swale wetland/upland complexes support many endangered or threatened species such as the Piping Plover, Pitcher's thistle, Lake Huron tansy, and Houghton's goldenrod. Due to a combination of the natural fragility of interdunal wetlands and the loss of shoreline habitat due to development along the Great Lakes shoreline, these habitats are threatened.
Marsh
A frequently or continually inundated wetland characterized by grass-like and other emergent vegetation adapted to saturated soil conditions. Typical marsh plants include rushes, reeds, sedges, cattails, and grasses. They are wet areas which can be periodically covered by standing or slow-moving water and are usually associated with ponds, rivers, streams, inland lakes, and the Great Lakes. Although some marshes have sandy soils, marshes usually have finer textured, nutrient rich soils with a high content of organic matter.
Many stretches of bedrock or till derived shorelines form small protected bays, typically less than three or four kilometers in width. These bays can be completely vegetated with emergent or submergent vegetation. Examples include Duck Bay and Mackinac Bay in the Les Cheneaux Islands on Lake Huron, Matchedash Bay on Lake Huron, and Bayfield Bay on Wolfe Island in Lake Ontario.
Tombolo
An island connected to the mainland by a beach ridge or series of beach ridges. Enclosed lagoons can contain dense growth of aquatic vegetation, and there is occasionally a fringe of emergent vegetation outside of the tombolo.
Interdunal Swale Wetland
A wetland dominated by grass-like vegetation that occurs in the low areas between sand dunes or beach ridges along the Great Lakes shoreline. These wetlands depend on the Great Lakes for their water source. As such, their water table and period of saturation fluctuates with Great Lakes water levels. Because of the highly variable ecosystem characteristics, and the fact that they exist nowhere else on earth, interdunal swale wetland/upland complexes support many endangered or threatened species such as the Piping Plover, Pitcher's thistle, Lake Huron tansy, and Houghton's goldenrod. Due to a combination of the natural fragility of interdunal wetlands and the loss of shoreline habitat due to development along the Great Lakes shoreline, these habitats are threatened.
Marsh
A frequently or continually inundated wetland characterized by grass-like and other emergent vegetation adapted to saturated soil conditions. Typical marsh plants include rushes, reeds, sedges, cattails, and grasses. They are wet areas which can be periodically covered by standing or slow-moving water and are usually associated with ponds, rivers, streams, inland lakes, and the Great Lakes. Although some marshes have sandy soils, marshes usually have finer textured, nutrient rich soils with a high content of organic matter.
Peatlands
Peatlands occur as thick peat deposits in old lake basins or as blankets of peat across the landscape. Their formation is due to the combination of cool temperatures and adequate rainfall in northern temperate regions around the earth. Peat-accumulating wetlands include both bogs and fens.
Bog
Bogs form in lake basins that are isolated from sources of ground water. Because normal rainwater (the only water source for true bogs) is slightly acidic, bog water tends to be slightly acidic. The acidic nature of bogs supports acid-loving (acidophilic) vegetation, especially Sphagnum mosses, and contributes to a deficiency in available plant nutrients. As a result, many plants, animals, and microbes have special adaptations.
Fen
A peat-accumulating wetland that receives some inputs of groundwater or drainage from surrounding mineral soils which typically results in alkaline waters and usually supports grass-like vegetation.
Swamp
A wetland dominated by trees or shrubs. Swamps are usually inundated or saturated periodically at some point during the growing season. The soils in swamps are usually rich in nutrients and organic matter. This is due to silt and organic matter deposited by flood events and the accumulation of organic matter (dead trees and other vegetation) over time.
Vernal Pool
An ephemeral wetland usually in a forested area. Vernal pools are small isolated wetlands that only hold water for a short time during the spring. After snowmelt, amphibians congregate in vernal pools to create another generation of frogs, toads, and salamanders. By midsummer, the water is gone from this important, yet ephemeral, wetland.
Wet Meadow
Grassland with saturated soil near the surface but without standing water for most of the year. Wet meadows contain grass-like vegetation and saturated soils, but seldom have water standing on the ground surface. Many wet meadows occur in the former lakeplain of the Great Lakes, especially in southeast Michigan and the Saginaw Bay watershed. Because these areas are relics from a former geologic epoch, they provide habitat for many plant species rare in Michigan that are typically adapted to prairies. Unfortunately, a large percentage have been severely degraded or converted to agriculture or housing.
Wet Prairie
Wet prairies are intermediate areas between a marsh and a wet meadow. They once covered the flat lakeplains of Southern Michigan, but are not considered rare. They typically experience seasonal flooding and are among the most diverse plant communities in Michigan.
Peatlands occur as thick peat deposits in old lake basins or as blankets of peat across the landscape. Their formation is due to the combination of cool temperatures and adequate rainfall in northern temperate regions around the earth. Peat-accumulating wetlands include both bogs and fens.
Bog
Bogs form in lake basins that are isolated from sources of ground water. Because normal rainwater (the only water source for true bogs) is slightly acidic, bog water tends to be slightly acidic. The acidic nature of bogs supports acid-loving (acidophilic) vegetation, especially Sphagnum mosses, and contributes to a deficiency in available plant nutrients. As a result, many plants, animals, and microbes have special adaptations.
Fen
A peat-accumulating wetland that receives some inputs of groundwater or drainage from surrounding mineral soils which typically results in alkaline waters and usually supports grass-like vegetation.
Swamp
A wetland dominated by trees or shrubs. Swamps are usually inundated or saturated periodically at some point during the growing season. The soils in swamps are usually rich in nutrients and organic matter. This is due to silt and organic matter deposited by flood events and the accumulation of organic matter (dead trees and other vegetation) over time.
Vernal Pool
An ephemeral wetland usually in a forested area. Vernal pools are small isolated wetlands that only hold water for a short time during the spring. After snowmelt, amphibians congregate in vernal pools to create another generation of frogs, toads, and salamanders. By midsummer, the water is gone from this important, yet ephemeral, wetland.
Wet Meadow
Grassland with saturated soil near the surface but without standing water for most of the year. Wet meadows contain grass-like vegetation and saturated soils, but seldom have water standing on the ground surface. Many wet meadows occur in the former lakeplain of the Great Lakes, especially in southeast Michigan and the Saginaw Bay watershed. Because these areas are relics from a former geologic epoch, they provide habitat for many plant species rare in Michigan that are typically adapted to prairies. Unfortunately, a large percentage have been severely degraded or converted to agriculture or housing.
Wet Prairie
Wet prairies are intermediate areas between a marsh and a wet meadow. They once covered the flat lakeplains of Southern Michigan, but are not considered rare. They typically experience seasonal flooding and are among the most diverse plant communities in Michigan.
