Natural Resources
Conservation Service
Ecological site F093BY004MI
Wet Lowlands
Last updated: 9/27/2023
Accessed: 11/13/2024
General information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
MLRA notes
Major Land Resource Area (MLRA): 093B–Superior Stony and Rocky Loamy Plains and Hills
The Wisconsin portion of this MLRA is a mixture of high-relief moraines and flat till plains with interspersed glacial meltwater deposits. It is bordered on the north by glaciolacustrine deposits of Glacial Lake Duluth and on the south by extensive pitted and unpitted outwash plains. The approximate land area is just under 600,000 acres (935 sq miles).
The Penokee-Gogebic Iron Range runs through the middle of the Wisconsin portion of this MLRA and into Michigian. The range is a hilly, bedrock-controlled moraine. The bedrock outcropping is composed of igneous and metamorphic materials and was created by inland folding and faulting of the ancient Superior continent when it collided with the Marshfield continent about 1.8 billion years ago (Dott & Attig, 2004). Volcanic and intrusive bedrock occurs in some places. This bedrock is overlain by a thin layer of glacial till deposited by the Chippewa Lobe.
To the north of the range is a former spillway for Glacial Lake Ontonagon. The flowing meltwater cut deep channels into the morainal systems. Glaciofluvial landforms here include old beaches and dunes. South of the range, along the southern edge of this MLRA, are rolling collapsed end moraines, pushed to their extent by the Chippewa and Ontonagon Lobes. The landscape is dotted with abundant kettle lakes and swamps, especially in the eastern portion. Ice-walled lake plains and eskers are also found along these collapsed moraines.
The climate is influenced by Lake Superior in areas near the lake, resulting in cooler summers, warmer winters, and greater precipitation – especially snowfall – compared to more inland locations. Historically, mixtures of eastern hemlock (Tsuga canadensis), sugar maple (Acer saccharum), yellow birch (Betula alleghaniensis), eastern white pine (Pinus strobus), and red pine (Pinus resinosa) covered the area. In wetter pockets (such as the swamps that dot the moraines to the south) white cedar (Thuja occidentalis), black spruce (Picea mariana), and tamarack (Larix laricina) were common (Finley, R., 1976).
Classification relationships
Relationship to Established Frameworks and Classification Systems:
Habitat Types of N. Wisconsin (Kotar, 2002): All sites in this ES key out to Fraxinus nigra – Acer rubrum/ Impatiens capensis (FnArI).
Biophysical Setting (Landfire, 2014): This ES is mapped as Boreal White Spruce-Fir-Hardwood Forest – Inland, Laurentian-Acadian Northern Hardwoods Forest – Hemlock, Eastern Boreal Floodplain, Boreal Acidic Peatland System, and Laurentian-Acadian Alkaline Conifer-Hardwood Swamp; though, it is likely most represented by the latter.
WDNR Natural Communities (WDNR (2015): This ES is most similar to the Northern Hardwood Swamp.
Hierarchical Framework Relationships:
Major Land Resource Area (MLRA): Superior Stoney and Rocky Loamy Plains and Hills, Eastern Part (93B)
USFS Subregions: Winegar Moraines (212Jc)
Small sections occur in the Gogebic-Penokee Iron Range (212Jb) subregion
Wisconsin DNR Ecological Landscapes: North Central Forest
Ecological site concept
The Wet Lowlands ecological site is scattered throughout MLRA 93B in depressions and drainageways on outwash and lake plains, moraines, and stream terraces. These sites are characterized by very deep, poorly drained soils formed in till, alluvium, and outwash deposits. Sites are subject to occasional ponding. Precipitation and runoff are the primary sources of water, but groundwater discharge may be a significant contribution. Sites remain saturated for long periods during the growing season and meet hydric soil requirements. Soils range from extremely acid to slightly alkaline. Some sites are wetlands.
The characteristic trait of Wet Lowlands the differentiates it from other sites is poor drainage. The organic sites (Acidic Poor Fens, and Mucky Swamps) also have poor drainage, but Wet Lowlands is in mineral soil. Other mineral soils outside this ecological site have improved drainage.
Associated sites
F093BY001MI |
Acidic Poor Fens Acidic poor fens consist of deep herbaceous organic material. These soils are very poorly drained and remain saturated throughout the year. They are very strongly to extremely acidic. These sites are wetlands. If there is a lower landscape position bordering a Wet Lowland site, it’s either an Acidic Poor Fen or a Mucky Swamp (described below). |
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F093BY002MI |
Mucky Swamps Mucky swamps consist of deep, highly decomposed herbaceous organic material. These soils are very poorly drained and remain saturated throughout the year. Some sites are subject to occasional ponding and flooding. They are neutral to moderately acidic. These are wetlands. If there is a lower landscape position bordering a Wet Lowland site, it may be a Mucky Swamp site. |
F093BY005MI |
Moist Lowlands Moist Lowlands occur on footslope positions across the landscape. Unlike Wet Lowlands, they are subject to neither flooding nor ponding. These soils form in till, lacustrine deposits, or outwash deposits and may be loamy to sandy. These sites are somewhat poorly drained and occur higher on the drainage sequence than Wet Lowlands. |
F093BY011MI |
Dry Uplands Dry Uplands are found in the sandiest, most permeable soils on the driest landscape positions. They are very deep and excessively drained. They occur much higher on the drainage sequence than Wet Lowlands. |
Similar sites
F093BY002MI |
Mucky Swamps Mucky Swamps consist of deep, highly decomposed herbaceous organic material. These soils are very poorly drained and remain saturated throughout the year. Some sites are subject to occasional ponding and flooding. They are neutral to moderately acidic. These are wetlands. Some Mucky Swamp sites have a vegetative community very similar to that of Wet Lowlands. |
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Table 1. Dominant plant species
Tree |
(1) Fraxinus nigra |
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Shrub |
(1) Corylus cornuta |
Herbaceous |
(1) Dryopteris carthusiana |
Click on box and path labels to scroll to the respective text.
Ecosystem states
T1A | - | Major stand replacing disturbance |
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T1B | - | Site cleared; agricultural practices |
R2A | - | Decreased frequency and duration ponding events |
T2A | - | Elimination of forest cover, application of agricultural practices |
State 1 submodel, plant communities
1.1.A | - | Natural mortality in the oldest age classes or sporadic small-scale blow-downs and/or ice storms create canopy openings |
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1.2.A | - | Time; natural succession |
State 2 submodel, plant communities
2.1.A | - | Decrease in ponding allows encroachment of tree species such as black ash on mounds |
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2.2.A | - | Increase frequency and duration of ponding |