Interdunal Wetland

Definition

Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

Interdunal wetlands occupy wind-created hollows that intersect the water table within active dune fields along the Great Lakes shores. They may also occur where moving sand encroaches on nearby wetlands, surrounding and isolating all or portions of them. The vegetation is difficult to characterize because of the small number of sites, the floristic variability that occurs, and the ephemeral nature of some occurrences. Plants that are at least somewhat representative of the community include twig-rush (Cladium mariscoides), little green sedge (Carex viridula), Baltic rush (Juncus balticus), silverweed (Potentilla anserina), seven-angled pipewort (Eriocaulon aquaticum), spike-rushes (Eleocharis spp.), ladies-tress orchids (Spiranthes spp.), and bladderworts (Utricularia cornuta and U. resupinata).

Dune systems are rare and not well developed in Wisconsin compared to Michigan where the prevailing winds and nearshore currents are conducive to moving large quantities of sand around. High-quality examples of interdunal wetlands are known from fewer than ten locations in Wisconsin. All occurrences are small, and only one of them approaches ten acres. Despite their rarity and limited distribution, these wetlands provide critical habitat for many uncommon plant species and provide resting and feeding areas for migrating and resident water birds.

Defining Characteristics and Similar Communities

Interdunal wetlands are distinguished by their location between dune ridges along the Great Lakes. They may superficially resemble northern sedge meadows, emergent marshes, or ephemeral ponds, but those communities rarely, if ever, occur in wet swales or hollows between sand dunes.

Rare animals

Species of Greatest Conservation Need

The following Species of Greatest Conservation Need are listed according to their level of association with the Interdunal Wetland 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 Interdunal Wetland, 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 Interdunal Wetland in Ecological Landscapes with opportunities for protection, restoration, and/or management. For more information, see the Wildlife Action Plan.

Central Lake Michigan Coastal

Though rare in this landscape, one of the state's largest interdunal wetlands occurs within Kohler-Andrae State Park (Sheboygan County).

Northern Lake Michigan Coastal

Several small but floristically rich occurrences are known from the Grand Traverse Islands off the northern Door Peninsula.

Superior Coastal Plain

All known occurrences are associated with sandscapes. Those in the Apostle Islands Archipelago are well-protected. Others, such as those at Wisconsin-Minnesota Points, are subject to intensive recreational use during the summer months and would benefit from additional protective measures as well as active efforts to control purple loosestrife and encroaching woody vegetation.

Photos

Click to view a larger version. Please considering donating your photos to the Natural Heritage Conservation Program for educational uses. Photo use

Interdunal Wetland 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.