Emergent Marsh

Definition

Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

Emergent marsh is dominated by robust emergent macrophytes, in pure stands of single species or in various mixtures. Dominants include cattails (Typha spp.), bulrushes (particularly Schoenoplectus acutus, S. tabernaemontani, and Bolboschoenus fluviatilis), bur-reeds (Sparganium spp.), giant reed (Phragmites australis), pickerel-weed (Pontederia cordata), water-plantains (Alisma spp.), arrowheads (Sagittaria spp.), the larger species of spike-rush (such as Eleocharis smallii), and wild rice (Zizania spp.). Emergent marsh can occur in a wide variety of hydrologic settings, including inland lake, Great Lakes, riverine and estuarine complexes.

Aquatic plants, including both emergent and submergent aquatic vegetation, form the foundation of healthy and flourishing aquatic ecosystems - both within lakes and rivers and on the shores and wetlands around them. They not only protect water quality, but they also produce life-giving oxygen. Aquatic plants are a lake's own filtering system, helping to clarify the water by absorbing nutrients like phosphorus and nitrogen that could stimulate algal blooms. Plant beds stabilize soft lake and river bottoms and reduce shoreline erosion by reducing the effect of waves and current.

Aquatic plants also serve as spawning habitat for fish and amphibians, as shelter for various life stages of a variety of species, and as nesting habitat for birds. Plant beds support populations of aquatic insects that serve as a food base for other species. Seeds and other plant parts provide vital nutrition to a number of waterfowl and other bird species. Healthy, native aquatic plant communities also help prevent the establishment of invasive exotic plants like Eurasian water-milfoil (Myriophyllum spicatum).

Defining Characteristics and Similar Communities

Emergent marsh often intergrades with and transitions to floating-leaved marsh or submergent marsh in deeper water but is dominated by emergent vegetation. Wild rice marsh is closely related to emergent marsh but is classified as a distinct natural community due to its dominance by wild rice (>50% relative cover compared to other emergent species). In addition, wild rice is an annual, unlike the robust perennial emergent species dominant in emergent marsh. Emergent marsh and southern sedge meadows may be similar, especially in wet sloughs along large rivers. While species like lake sedge (Carex lacustris) may occur in both systems, emergent marshes have a higher combined cover of other emergent species (e.g., cattails, bulrush, bur-reeds, etc.) relative to sedges, while sedge meadows have a higher combined cover of sedges and native graminoids such as Canada bluejoint grass (Calamagrostis canadensis).

Rare animals

Species of Greatest Conservation Need

The following Species of Greatest Conservation Need are listed according to their level of association with the Emergent 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.

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.

Landscapes

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

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.

Threats/Actions

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

Considerations

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

Central Lake Michigan Coastal

Invasive plants (e.g., Phragmites, reed canary grass, purple loosestrife) can replace native plants and affect aquatic communities. Continuing effects of past management (e.g., filling marshes) are evident. Grass Lake (Calument County) supports a good emergent aquatic community. Kewaunee River Marsh (Kewaunee County) and Little Tail Point (Brown County) are examples of other emergent communities in public ownership.

Central Sand Hills

Invasive plants (e.g., reed canary grass, giant reed and purple loosestrife) can replace native plants and affect aquatic communities. Effects of past management (e.g., filling marshes) are very evident in this Ecological Landscape. Grassy Lake Wildlife Area (Columbia County) and Lawrence Creek State Natural Area (Marquette County) are examples of high quality emergent aquatic communities here.

Central Sand Plains

Many streams have been hydrologically altered and marshes drained here for various agricultural purposes. Research may be necessary to determine whether emergent communities can be restored under this scenario of flow alteration. Windy Run and Marsh (Clark County) and Monroe County Flowage in the Meadow Valley Wildlife Area are examples of this community here.

Forest Transition

Invasive plants (e.g., purple loosestrife) can replace native plants. Dams have raised water levels to eliminate this community type in some sites but also create marsh habitat in other locations. Drainage for agricultural use reduced marsh habitat. Pope Lake (Waushara County) and Tenmile Creek Marsh (Rusk County) typify this community here.

North Central Forest

Invasive plants (e.g., purple loosestrife) can replace native plants. Dams have raised water levels and affected this community type in some sites but created marsh habitat in locations further upstream. Totagatic Lake (Bayfield County) is a quality site.

Northeast Sands

Development on popular lakes may pose a threat to this community. Utricularia Bay on Warrington Lake (Oconto County) is an excellent example of this community type here, and several others are protected on the Menominee reservation. The ability of lake classification to protect remaining populations of emergent vegetation on lakes subject to housing development and recreational use should be investigated.

Northern Highland

This Ecological Landscape contains some unique and sensitive marsh types. Large areas in public ownership help to ensure the viability of this community here. Frog Lake and Pine State Natural Area (Iron County) showcase high quality examples of this type.

Northern Lake Michigan Coastal

Significant alterations to wetlands have impacted this community here, but some restoration attempts have restored this community in wildlife areas along the west shore of Green Bay, to the benefit of fish such as northern pike. Mink River Estuary and the Dunes Lake area (both in Door County) contain intact examples of emergent marsh.

Northwest Lowlands

Most problems due to lakeshore development and recreational use are associated with the larger developed lakes. Invasive plants (e.g., purple loosestrife) have replaced native plants in some areas. Pockets of marsh exist along lake and stream shores, as well as state-managed wildlife flowages (Douglas County).

Northwest Sands

Cranberry operations, though currently limited here, have the potential to decrease the amount of wetland habitat, alter natural communities, and affect local hydrology and water quality. An appreciable number of lakes still support viable emergent aquatic communities here. Some of the larger marshes in this Ecological Landscape occur along impounded portions of rivers or small streams. Good examples of the emergent marsh community include the Gordon Flowage on the St. Croix River (Burnett County) and some of the managed flowages at Crex Meadows (Wood County).

Southeast Glacial Plains

Invasive plants (e.g., Phragmites, reed canary grass, purple loosestrife, flowering rush, glossy buckthorn, narrow-leaved cattail) can replace native plants and affect aquatic communities. Many marshes are becoming highly dominated by cattails. Botulism is a concern when oxygen content is low. Remaining lead shot in hard-bottomed water bodies still occasionally results in poisoning. Carp are a threat, and so are effects of carp control efforts. There are continuing effects of past management (e.g., draining and filling marshes). This Ecological Landscape formerly included many marshes. It is among the best Ecological Landscapes regarding the potential for restoring and managing this type. Existing sites include Horicon Marsh (Dodge County) (and the satellite Fox River Crane Marsh), Rush Lake and Fox River marshes (Winnebago County), many Wildlife Areas, and a number of Waterfowl Production Areas. Restoration areas include the Glacial HRA (Fond du Lac County) (using the wetland reserve program). Formerly drained wetlands (e.g., muck farms) have been recently purchased and may be converted and managed as marsh. More of this community type should be protected by working with conservation managers and interest groups. Watersheds should be managed to control runoff from surrounding agricultural areas that may contribute nutrients and sediment. Drawdowns for shorebird management are effective, but the needs of amphibians and reptiles should be considered; consider timing drawdowns to reduce the threat of botulism. These sites should be monitored to determine whether management is maintaining native diversity and the effects of non-native cattails should be researched.

Southern Lake Michigan Coastal

Increasing population levels due to proximity to the expanding Milwaukee metropolitan area continue to drive rapidly increasing development and land use conversion. Land use planning that is not comprehensive and does not emphasize conservation considerations can lead to development in locations that limit options for restoring and managing this community. Continuing effects of past management (e.g., filling marshes) are evident on the landscape, and pose barriers to restoring this community here. Past drainage for agricultural use reduced marsh habitat. Agricultural activities in close proximity to water bodies have led to sedimentation, eutrophication, and increased runoff, causing detrimental changes to community structure. Runoff is likely increasing due to development and increases in impervious surface area. Invasive plants (e.g., Phragmites, reed canary grass, purple loosestrife) can replace native plants and affect aquatic communities. Invasive animals (e.g., carp, rusty crayfish) are also a problem for this community type. Use of existing land use plans that call for conservation actions should be encouraged. Watersheds should be managed to control runoff that may contribute nutrients and sediment. Brighton Marsh and Woodland (Kenosha County) and Mission Hills Wetlands (Milwaukee County) are good examples of this community in southeast Wisconsin.

Superior Coastal Plain

Disturbance from recreational powerboats coming into rivers from Lake Superior can cause sedimentation and physical damage to aquatic plants. Eutrophication (in St. Louis River estuary, Port Wing) can cause detrimental changes to community structure. Invasive plants (e.g., purple loosestrife, Phragmites, reed canary grass) have replaced native plants. Soil erosion and sedimentation from uplands into water bodies is a particular threat in this Ecological Landscape due to the erodible soils. Agriculture, impermeable surfaces, and lack of conifers contribute to peakflow episodes during spring snowmelt. Unsustainable forest management practices can result in soil erosion and water quality issues. This type is primarily associated with coastal embayments on Lake Superior. Inland lakes are scarce in this Ecological Landscape. Uplands within the watershed should be reforested, restoring conifers where possible. Best Management Practices and other sustainable forest management practices should be used to limit detrimental soil and water effects. Adaptive management techniques should be used to restore structure and composition. More information on land use in the watershed should be gathered and effects on peakflows into emergent aquatic community sites should be researched.

Western Coulee and Ridges

Development on ridges above rivers can alter shoreline habitat and increase erosion. Rip-rapping, levees, seawalls, and dikes have been constructed (these have some positive effects in protecting marshes behind dikes). Invasive plants (e.g., reed canary grass, purple loosestrife) can replace native plants. Invasive animals (e.g., common carp) are also a problem for this community type. An astounding abundance of dams in this Ecological Landscape raised water levels to eliminate this community type in some sites, but created marsh habitat in other locations. Dams also change timing and duration of water level fluctuations. Barge traffic on the Mississippi requires dredging and disposal of materials, which stirs up bottom sediments, and results in wave impacts. Past drainage for agricultural uses, and filling for roads, railroads, and industrial sites, reduced marsh habitat. Competing economic interests limit opportunities for this type in the Ecological Landscape, especially in the Mississippi River valley. The Mississippi River corridor is of continental importance to migratory waterfowl. This community is found primarily in the backwaters of large rivers (e.g., Mississippi (Grant, Crawford, Pepin, Pierce, Trempealeau Counties), Chippewa (Pepin and Buffalo Counties), Wisconsin (Crawford and Grant Counties), and Black Rivers (LaCrosse County)). Emergent marsh should be managed as a complex with floodplain forest, submergent marsh, wet meadow, shrub-carr, and adjoining uplands. Advocating for river flow management and other actions that are more beneficial to emergent plant communities, fish and wildlife should be continued. The Chippewa River Bottoms (Buffalo County) and the Trempealeau Delta (Trempealeau County) are examples of healthy emergent aquatic communities.

Western Prairie

Development on hilltops above rivers can alter shoreline habitat and increase erosion. Increasing human population levels due to the expansion of the nearby Twin Cities metropolitan area has resulted in rapidly increasing development. Agricultural practices are often used too close to pothole habitat. Invasive plants (e.g., reed canary grass, purple loosestrife) can replace native plants. Invasive animals (e.g., carp) are also a problem for this community type. Raising baitfish in potholes is a threat. There are few dams in this Ecological Landscape, but some large ones exist on the Willow and Apple Rivers, and may have raised water levels to eliminate this community type in some sites and create marsh habitat in other locations. Dams also change the timing and duration of fluctuations in water levels. Past drainage for agricultural use reduced marsh habitat. Past filling for roads and railroads has impacted the community type by altering hydrology. This community is found in this Ecological Landscape primarily in pothole lakes and also on backwaters of the St Croix River (Pierce County). Historically, this Ecological Landscape was the only part of the state where prairie potholes were found. Emergent pothole vegetation has dwindled in remaining potholes; the few remaining sites should be preserved and managed as a complex with other grassland or prairie communities, and floodplain forests along the St. Croix River. Incentives should be provided to buffer potholes with prairie or grassland to protect the emergent aquatic community. Detrimental recreational activities on the St. Croix River should be excluded by such means as creating no-wake zones near sensitive marsh habitat. Uplands should be buffered and shorelines should be managed to prevent erosion and sedimentation, and limit pollutant inputs. Shorelines should be restored where possible. Introduction of baitfish into potholes, which disrupts amphibian, invertebrate, and other components of these communities, should be controlled. The St. Croix Islands Wildlife Area (St. Croix County) remains a high quality example of this community.

Photos

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Emergent Marsh Photos

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.