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Ryan O'Connor
Natural Heritage Inventory Ecologist

Coastal Plain Marsh

State Rank: S1     Global Rank: G2?   what are these ranks?


Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

Counties shaded blue have documented occurrences for Coastal Plain Marsh in the Wisconsin Natural Heritage Inventory database.

Coastal Plain marsh is limited to a few sites within the sandy beds or margins of extinct glacial lakes, on level or gently sloping glacial outwash sands, and, possibly, in glacial tunnel channels. Layers of fine-textured, relatively impermeable materials occur at shallow depths beneath the surface of at least some of these waterbodies and wetlands, and they're probably essential to normal hydrologic function. The lake or pond waters are nutrient-poor and acidic, and all known occurrences of the community are small, or at most, medium-sized. Historically the surrounding vegetation included oak and pine barrens, dry acid forests composed of oaks, pines, or mixtures, sand prairie, and various peatland communities. Periodic wildfire would have been the major disturbance force in all of these communities prior to European settlement and the implementation of fire suppression policies.

Coastal plain marsh develops on sandy lake or pond shores, sometimes with the sandy waterbody margins partially covered by localized, discontinuous layers of shallow peat or muck. At several sites in central Wisconsin, members of the coastal plain marsh community - including some of the rare disjuncts - have colonized, at least temporarily, ditches, borrow pits, log landings, and haul roads. At all of these sites, the ranker, overlying vegetation has been stripped away, exposing wet sand that may be fed by slow groundwater seepage from the surrounding uplands. Sometimes in these sites there are shallow excavations, creating small ponds. The long-term conservation values of such sites are uncertain, as is the source of propagules for the flora that colonizes them. In the natural systems, many, if not most of the propagules come from the local seedbank. In those sites that are of anthropogenic origin, the source is unclear, but it seems likely that, for some species, dispersal may be aided by animals (especially, but perhaps not limited to, migratory birds), and by water moving through the ditches.

The vegetation often demonstrates strong zonation, with water depth the determinant factor. The deeper, more permanent waters support aquatic macrophytes such as water-shield (Brasenia spp.), pondweeds (Potamogeton spp.), and bladderworts (Utricularia spp.). The inshore shallows and pond margins are often dominated by diverse assemblages of short or medium stature graminoid plants including grasses, sedges (e.g., from the genera Cyperus, Eleocharis, Fimbristylis, Fuirena, Rhynchospora, Scleria, and Scirpus), and rushes (Juncus spp.), as well as forbs like milkworts (Polygala cruciata and P. sanguinea), tooth-cup (Rotala ramosior), meadow-beauty (Rhexia virginica), lance- leaved violet (Viola lanceolata), yellow-eyed grass (Xyris tora), and several of the small St. John's-worts (Hypericum spp.). The uppermost, seldom-inundated margins of the wetland are typically vegetated with more robust perennials, such as grass-leaved goldenrod (Euthamia graminifolia), Canada bluejoint grass (Calamagrostis canadensis), hardhack (Spiraea tomentosa), meadowsweet (Spiraea alba), boneset (Eupatorium perfoliatum), spotted Joe-Pye-weed (Eutrochium maculatum), and asters.

Coastal plain marsh was not recognized as a distinct community by Curtis (1959), though he did acknowledge the presence of a coastal plain flora in the state. The unusual distributions of the coastal plain plants have long been recognized by Wisconsin botanists, however. Most of the information on this type comes from farther east; Michigan, Indiana, Ontario, and New York. In Michigan and Indiana, the distribution of this community is strongly correlated with post-glacial levels of Lake Michigan. Wisconsin occurrences support fewer of the rarities and extreme disjunct species than stands in Michigan and points eastward, but the same general patterns of geographic origin and distribution, and many habitat similarities, are in evidence.

Defining Characteristics and Similar Communities

The presence of Atlantic Coastal Plain disjuncts sets this community apart from other similar communities such as inland beach. Coastal Plain marshes have some similarities with other wetland communities like sedge meadows and moist sandy meadows, but these communities lack the strong vegetation zonation typical of Coastal Plain marshes in addition to lacking Atlantic Coastal Plain specialists. Deeper water areas within Coastal Plain marshes may contain floating-leaved or submerged aquatic macrophytes like water-shield (Brasenia schreberi), but are usually treated as one of the zones of the Coastal Plain marsh community rather than separated as their own entity (see natural community overview).

Rare animals

Species of Greatest Conservation Need

Wisconsin Wildlife Action Plan graphic

The following Species of Greatest Conservation Need are listed according to their level of association with the Coastal Plain Marsh natural community type, based on the findings in Wisconsin's 2015 Wildlife Action Plan.

Scores: 3 = high association, 2 = moderate association, and 1 = low association. See the key to association scores for complete definitions.

Pickerel FrogLithobates palustris1

Purple MartinProgne subis2
Rufa Red KnotCalidris canutus rufa2
Black-necked StiltHimantopus mexicanus1

Dragonflies and damselfliesScore
Ringed BoghaunterWilliamsonia lintneri2
Zigzag DarnerAeshna sitchensis2
Alkali BluetEnallagma clausum1
Incurvate EmeraldSomatochlora incurvata1
Mottled DarnerAeshna clepsydra1
Spatterdock DarnerRhionaeschna mutata1
Subarctic DarnerAeshna subarctica1
Swamp DarnerEpiaeschna heros1

Grasshoppers and alliesScore
Bog ConeheadNeoconocephalus lyristes1
Spotted-winged GrasshopperOrphulella pelidna1

Leafhoppers and true bugsScore
A LeafhopperLimotettix pseudosphagneticus1

Big Brown BatEptesicus fuscus2
Little Brown BatMyotis lucifugus2
Northern Long-eared BatMyotis septentrionalis2
Silver-haired BatLasionycteris noctivagans2
Eastern PipistrellePerimyotis subflavus1

Blanding's TurtleEmydoidea blandingii2
Plains GartersnakeThamnophis radix2

Please see Section 2. Approach and Methods of the Wildlife Action Plan to learn how this information was developed.

Rare plants

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

Scores: 3 = "significantly associated," 2 = "moderately associated," and 1 = "minimally associated."
Scientific Name Common Name Score
Bartonia paniculata Twining Screwstem 3
Carex cumulata Clustered Sedge 3
Carex livida Livid Sedge 2
Carex sychnocephala Many-headed Sedge 3
Cuscuta coryli Hazel Dodder 3
Cuscuta pentagona Field Dodder 2
Cuscuta polygonorum Knotweed Dodder 3
Didiplis diandra Water-purslane 3
Elatine triandra Longstem Water-wort 2
Eleocharis engelmannii Engelmann's Spike-rush 2
Eleocharis flavescens var. olivacea Capitate Spike-rush 3
Eleocharis wolfii Wolf Spike-rush 3
Fuirena pumila Dwarf Umbrella Sedge 3
Juncus marginatus Grassleaf Rush 3
Lycopodiella margueritae Northern Prostrate Clubmoss 3
Rhexia virginica Virginia Meadow-beauty 3
Rhynchospora scirpoides Long-beaked Bald-rush 3
Rotala ramosior Toothcup 2
Schoenoplectus torreyi Torrey's Bulrush 3
Scleria reticularis Netted Nutrush 3
Symphyotrichum dumosum var. strictior Bushy Aster 3
Symphyotrichum robynsianum Robyns' Aster 2
Utricularia resupinata Northeastern Bladderwort 2


The following Ecological Landscapes have the best opportunities to manage for Coastal Plain Marsh, based on the Ecological Landscapes of Wisconsin Handbook.

Map of the Ecological Landscapes of Wisconsin.

Ecological LandscapeOpportunity
Central Sand HillsMajor
Central Sand PlainsImportant

Major (3 on map)
A major opportunity for sustaining the natural community in the Ecological Landscape exists, either because many significant occurrences of the natural community have been recorded in the landscape or major restoration activities are likely to be successful maintaining the community's composition, structure, and ecological function over a longer period of time.

Important (2 on map)
Although the natural community does not occur extensively or commonly in the Ecological Landscape, one to several occurrences do occur and are important in sustaining the community in the state. In some cases, important opportunities may exist because the natural community may be restricted to just one or a few Ecological Landscapes within the state and there may be a lack of opportunities elsewhere.

Present (1 on map)
The natural community occurs in the Ecological Landscape, but better management opportunities appear to exist in other parts of the state.


Wisconsin Wildlife Action Plan graphic

What are conservation actions?

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for natural communities


The following are additional considerations for Coastal Plain Marsh in Ecological Landscapes with opportunities for protection, restoration, and/or management. For more information, see the Wildlife Action Plan.

Central Sand Hills

Known occurrences are quite fragile, and a number of them are in private ownership. Notable examples of this community occur in the vicinity of Mud Lake (Waushara County) and Silver lake (Marquette County).

Central Sand Plains

Natural lakes are virtually absent from this Ecological Landscape, with the major exception of sloughs and backwaters that occur in the floodplains of the major rivers. The few known examples of this community type in the Central Sands are highly threatened by inappropriate use of off-road vehicles and hydrologic modifications, despite occurring on public land. There are numerous stands of anthropogenic origin. A subset of these should be monitored over time, to gain better understanding of the viability for rare species and conservation value over the long-term. A single occurrence of this type has been found in the Western Coulee and Ridges Ecological Landscape, at Fort McCoy Military Reservation. The site, which is at least partially of human origin, is currently being protected by natural resource managers and the US Army. It is very close to the boundary of the Central Sand Plains Ecological Landscape, and the soils, topography, and vegetation surrounding the site are much more similar to that found in the Central Sand Plains than they are to that found in the Western Coulees and Ridges.


Coastal Plain Marsh Photos

Coastal Plain Marsh Photo

The Coastal Plain Marsh may support assemblages of unusual species. Eastern Jackson County, during a very dry year.

Photo by Emmet Judziewicz.

Coastal Plain Marsh Photo

The coastal plain marsh community is notable for its unusual herbaceous flora, which may include a number of strikingly disjunct species. Jackson County.

Photo by Thomas Meyer.

Note: photos are provided to illustrate various examples of natural community types. A single photograph cannot represent the range of variability inherent in a given community type. Some of these photos explicitly illustrate unusual and distinctive community variants. The community photo galleries are a work in progress that we will expand and improve in the future.

Last revised: Wednesday, June 16, 2021