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Ryan O'Connor
Natural Heritage Inventory Ecologist

Central Poor Fen

State Rank: S3     Global Rank: G3G4   what are these ranks?


Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

Counties shaded blue have documented occurrences for Central Poor Fen in the Wisconsin Natural Heritage Inventory database.

These open, acidic, low nutrient peatlands occur within the Central Sand Plains of Wisconsin. Central poor fens are floristically depauperate and generally sedge dominated (Carex oligosperma, C. lasiocarpa, and C. utriculata). Bluejoint grass (Calamagrostis canadensis) is a frequent associate and may co-dominate some stands. Sphagnum moss carpets are common but typically lack pronounced hummocks and hollows. Shrubs are present but not dominant, hard-hack (Spiraea tomentosa) is the most consistent in presence, and cover of ericads is generally low. Other characteristic associates include wool grass (Scirpus cyperinus), cotton-grasses (Eriophorum spp.), swamp-candles (Lysimachia terrestris), and Kalm's St. John's-wort (Hypericum kalmianum). A zone of northern tall shrubs is sometimes present, composed of black chokeberry (Aronia melanocarpa, hollys (Ilexspp.), and bog birch (Betula pumila). This community often intergrades with northern tamarack swamp or black spruce swamp. Disturbance of this community through mossing may significantly alter community composition, as recolonization by at least some of the vascular plants is very slow. Many plants characteristic of poor fen communities farther north are rare or absent in these central sands peatlands.

Defining Characteristics and Similar Communities

Central poor fens can be distinguished from poor fens by their location in the Central Sand Plains ecological landscape and their relative lack of calciphiles, carnivorous plants, and pink-flowered orchids. Central poor fens are similar to northern and southern sedge meadows in that sedges are dominant, but are much more acidic, usually with a nearly continuous carpet of Sphagnum moss. In contrast, Sphagnum is usually sparser in northern sedge meadows, which range from acidic to neutral, and is usually absent in southern sedge meadows, which tend to have neutral to calcareous soils. Central poor fens may resemble open bogs but lack the pronounced hummock-hollow topography and dominance of leatherleaf and other ericads typical of open bogs. Central poor fens are often bordered by northern tamarack swamp or black spruce swamp but are distinguished by having <25% tree cover. They are also commonly bordered by alder thicket but have <50% cover of tall shrubs.

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 Central Poor Fen 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

Cantrall's Bog BeetleLiodessus cantralli2

American BitternBotaurus lentiginosus3
Yellow RailCoturnicops noveboracensis3
American Black DuckAnas rubripes2
BobolinkDolichonyx oryzivorus2
Henslow's SparrowAmmodramus henslowii2
Le Conte's SparrowAmmodramus leconteii2
Olive-sided FlycatcherContopus cooperi2
Rusty BlackbirdEuphagus carolinus2
Whooping CraneGrus americana2
Black-backed WoodpeckerPicoides arcticus1
Sharp-tailed GrouseTympanuchus phasianellus1
Short-eared OwlAsio flammeus1

Butterflies and mothsScore
Midwestern Fen BuckmothHemileuca nevadensis ssp. 31
Swamp MetalmarkCalephelis muticum1

Dragonflies and damselfliesScore
Forcipate EmeraldSomatochlora forcipata3
Incurvate EmeraldSomatochlora incurvata3
Ringed BoghaunterWilliamsonia lintneri3
Subarctic DarnerAeshna subarctica3
Sphagnum SpriteNehalennia gracilis2
Zigzag DarnerAeshna sitchensis2

Grasshoppers and alliesScore
Bog ConeheadNeoconocephalus lyristes1
Spotted-winged GrasshopperOrphulella pelidna1

Leafhoppers and true bugsScore
A LeafhopperLimotettix elegans1
A LeafhopperLimotettix pseudosphagneticus1

Big Brown BatEptesicus fuscus2
Little Brown BatMyotis lucifugus2
Northern Long-eared BatMyotis septentrionalis2
Tricolored BatPerimyotis subflavus2
Water ShrewSorex palustris1

Eastern MassasaugaSistrurus catenatus3
Eastern RibbonsnakeThamnophis sauritus3
Blanding's TurtleEmydoidea blandingii1
Plains GartersnakeThamnophis radix1
Wood TurtleGlyptemys insculpta1

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
Lycopodiella margueritae Northern Prostrate Clubmoss 3


The following Ecological Landscapes have the best opportunities to manage for Central Poor Fen, based on the Ecological Landscapes of Wisconsin Handbook.

Map of the Ecological Landscapes of Wisconsin.

Ecological LandscapeOpportunity
Central Sand PlainsMajor
Central Sand HillsPresent

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


Central Poor Fen Photos

Central Poor Fen Photo

Vast wetland is a remnant of "The Great Swamp of Central WI", which occupied a large portion of extinct Glacial Lake Wisconsin. Sedges and sphagnum mosses are dominant.

Photo by Eric Epstein.

Central Poor Fen Photo

Central poor fen groundlayer exhibiting higher nutrient availability near the upland/wetland boundary. Carex utriculata is dominant, Spiraea tomentosa, and Toxicodendron vernix.

Photo by Drew Feldkirchner.

Central Poor Fen Photo

Island of jack pine and shrubs in poor fen. Mucky opening in the herb layer is important habitat for rare invertebrates. Carex urticulata dominant, with Spiraea tomentosa, Glyceria canadensis, Dulictium, Scirpus.

Photo by Drew Feldkirchner.

Central Poor Fen Photo

Central poor fen with scatterd shrubs and sparse trees in a broad peatland basin in Wood Co.

Photo by Ryan O'Connor.

Central Poor Fen Photo

Central poor fen dominated by Carex utriculata with Spiraea tomentosa, Solidago uliginosa, widely scattered bog birch and stunted white pine in a broad peatland basin.

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