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For information on Wisconsin's natural communities, contact:
Ryan O'Connor
Natural Heritage Inventory Ecologist

Bog Relict

State Rank: S3     Global Rank: G3   what are these ranks?


Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

Counties shaded blue have documented occurrences for Bog Relict in the Wisconsin Natural Heritage Inventory database.

Bog Relicts are semi-open tamarack-dominated forests and associated shrub-dominated peatlands that occur in the southernmost regions of Wisconsin, including some that are close to the Illinois border. Many of these sites are near the southern range limits for many of the species they support and are also quite isolated from one another. They support many nutrient-demanding species but may include a limited subset of the more northern oligotrophic peatland associates (e.g., Sphagnum mosses, ericaceous shrubs, and "bog" sedges). The tamarack canopy is often quite open and discontinuous, due to windthrow, beaver activity, or other reasons. Poison sumac (Toxicodendron vernix) is often present, and is sometimes the most abundant tall shrub. Speckled alder (Alnus incana), nannyberry (Viburnum lentago), willows (Salix spp.), and dogwoods (Cornus spp.) are often common associates.

These sites are typically small, in kettle depressions on outwash or sometimes ground moraine landforms. Many of these stands are fed by groundwater seepage. The surface may include areas of relatively firm peat, but watery muck is often present as well.

Defining Characteristics and Similar Communities

Bog relict is defined as a southern minerotrophic peatland having, on average across a site, up to 25% cover of trees (mostly tamarack) and/or 50% cover of shrubs, which includes a high abundance of poison sumac and the presence of ericaceous shrubs. It can be differentiated from shrub-carr by its partial canopy of tamarack and presence of northern "bog" species such as ericaceous shrubs and Sphagnum mosses. Bog relict is closely related to southern tamarack swamp, but is conceptually broader and more encompassing, as it includes the full mosaic of northern peatland vegetation (forest, shrub, and herb) occurring within a given insular wetland basin. In addition, the term has generally been applied to small discrete and disjunct sites, located far to the south of the typical range of the acid peatland communities. Southern tamarack swamp is differentiated from bog relict by its higher canopy cover (over 25%) and canopy tree composition that includes swamp hardwood species such as American elm, black ash, red maple, and yellow birch.

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 Bog Relict 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.

Four-toed SalamanderHemidactylium scutatum3
Mink FrogLithobates septentrionalis2
Pickerel FrogLithobates palustris2

Rusty BlackbirdEuphagus carolinus2
American WoodcockScolopax minor1
Golden-winged WarblerVermivora chrysoptera1

Butterflies and mothsScore
Midwestern Fen BuckmothHemileuca nevadensis ssp. 32
Swamp MetalmarkCalephelis muticum1

Dragonflies and damselfliesScore
Subarctic DarnerAeshna subarctica1

Grasshoppers and alliesScore
Spotted-winged GrasshopperOrphulella pelidna2
Bog ConeheadNeoconocephalus lyristes1

Big Brown BatEptesicus fuscus2
Little Brown BatMyotis lucifugus2
Silver-haired BatLasionycteris noctivagans2
Northern Long-eared BatMyotis septentrionalis1
Tricolored BatPerimyotis subflavus1
Water ShrewSorex palustris1

Eastern RibbonsnakeThamnophis sauritus3
Blanding's TurtleEmydoidea blandingii1

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
Carex livida Livid Sedge 2
Carex suberecta Prairie Straw Sedge 1
Eleocharis flavescens var. olivacea Capitate Spike-rush 1
Eleocharis quinqueflora Few-flowered Spike-rush 1
Platanthera leucophaea Eastern Prairie White Fringed Orchid 1


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

Map of the Ecological Landscapes of Wisconsin.

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 Bog Relict in Ecological Landscapes with opportunities for protection, restoration, and/or management. For more information, see the Wildlife Action Plan.

Central Sand Hills

Changes in hydrology due to development can be detrimental to this community type. There are continuing effects from past hydrologic changes (e.g., ditching, dike construction, road building, etc.). Some agricultural practices can result in soil erosion and water quality problems (e.g., sedimentation and high nutrient loads). Invasives are serious problems in some southern tamarack stands. Fragmentation and stand isolation affect this type in central and southern Wisconsin.

Southeast Glacial Plains

Invasive non-native plants are a problem in southern tamarack stands (e.g., glossy buckthorn). Poison sumac can be abundant in this community, making work in this type difficult. Many tamarack stands are not regenerating and the larger trees are experiencing dieback. Fragmentation and stand isolation are significant issues in this EL. The large forested peatlands in Jefferson County, in the Mukwonago River watershed, and at a few other locations are now classified as southern tamarack swamp. Past drainage to create muck farms and pasture eliminated much of the swamp conifer community here. Rare species include northern plants and animals at their southern range limits, but also some that are most often associated with southern "fen" habitats. Fire may have played an important role in maintaining this type historically. Some stands appear to be succeeding to hardwoods such as red maple. Restoration techniques need to be developed for this "type" (using the term broadly) in the southern part of its range. At some locations (e.g., Mukwonago River) it would be appropriate to manage bog relict with southern tamarack swamp, calcareous fen, southern sedge meadow, shrub-carr, oak opening, or oak woodland/southern dry forest.

Southern Lake Michigan Coastal

Invasives are a significant problem in southern peatlands. The "northern" understory is represented by a very reduced subset of plants in this Ecological Landscape. Often, conifers are not regenerating. Stand isolation and fragmentation are major issues. High deer densities, fire suppression, and succession may all be affecting species composition and stand structure. This type is extremely limited in acreage in this Ecological Landscape and should be embedded in other forest habitats where possible, or buffered from potentially deleterious land uses. More survey work is needed to assess the current condition of known stands. Restoration techniques should be developed for this type in southern Wisconsin.


Bog Relict Photos

Bog Relict Photo

Photo by Thomas Meyer.

Bog Relict Photo

Bog relict at Goose Lake Drumlins SNA in Dane Co. featuring sparse tamaracks and scattered leatherleaf mixed with minerotrophic sedges and forbs.

Photo by Ryan O'Connor.

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: Tuesday, August 30, 2022