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Ryan O'Connor
Natural Heritage Inventory Ecologist

Boreal Rich Fen

State Rank: S2     Global Rank: G4G5   what are these ranks?


Detailed Community Description from Ecological Landscapes of Wisconsin

General natural community overview

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

Boreal rich fen is a rare open peatland community of northern Wisconsin that is associated with glacial moraines, or less commonly, outwash landforms, in which the underlying substrate includes calcareous materials. Like many other northern peatlands, nutrient levels are low, but pH is significantly higher than in the poor fen and open bog communities and influences the plant composition. Sphagnum mosses are of lesser importance in this type than are the so-called "brown" mosses (e.g., from the genera Campylium, Drepanocladus, or Scorpidium). Characteristic vascular plants may include woolly sedge (Carex lasiocarpa), twig-rush (Cladium mariscoides), white beak-rush (Rhynchospora alba), beaked bladderwort (Utricularia cornuta), rushes (Juncus spp.), Hudson Bay cotton-grass (Scirpus hudsonianus), rush aster (Symphyotrichum boreale), and buckbean (Menyanthes trifoliata).

The most nutrient-rich boreal rich fens occur on the Door Peninsula, which is underlain by calcareous bedrock and mantled with calcareous till. Here, in addition to the species mentioned above, the open peatlands may support species such as coast sedge (Carex exilis), linear-leaved sundew (Drosera linearis), brook lobelia (Lobelia kalmii), grass-of-Parnassus (Parnassia glauca), shrubby cinquefoil (Dasiphora fruticosa), hair beak-rush (Rhynchospora capillacea), and tufted bulrush (Trichophorum cespitosum). The proximity of carbonate-enriched bedrock is almost certainly among the factors responsible for the composition of the boreal rich fens in this region.

Shrub phases of this community also occur, in which shrubby cinquefoil (Dasiphora fruticosa), bog birch (Betula pumila), sage willow (Salix candida), and speckled alder (Alnus incana) may be present in significant amounts, and collectively form the dominant plant cover.

Defining Characteristics and Similar Communities

Boreal rich fens are distinguished by a constant supply of groundwater high in calcium and magnesium carbonates. They can be differentiated from poor fens by having a higher pH, a higher abundance of calciphiles, and a lower abundance of Sphagnum mosses. They are superficially similar to northern sedge meadows, but contain numerous fen specialists, which are usually lacking or have low abundance in sedge meadows. Boreal rich fens may have similar species to some Great Lakes shore fens, especially in Door County, but are usually more species diverse and are found further inland rather than in coastal embayments, lagoons, and river mouths, thus lacking the influences of changing Great Lakes water levels. They also share similarities with calcareous fens, but are found in northern Wisconsin, while calcareous fens occur exclusively in southern and central Wisconsin. Where shrub phases of boreal rich fens occur, they can be distinguished from shrub-carr by having less than 50% cover of tall shrubs (>5 feet tall).

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 Boreal Rich 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.

Mink FrogLithobates septentrionalis2
Pickerel FrogLithobates palustris1

Ants, wasps, and beesScore
Frigid Bumble BeeBombus frigidus1

Yellow RailCoturnicops noveboracensis2
Connecticut WarblerOporornis agilis1
Golden-winged WarblerVermivora chrysoptera1
Le Conte's SparrowAmmodramus leconteii1
Nelson's SparrowAmmodramus nelsoni1

Butterflies and mothsScore
Swamp MetalmarkCalephelis muticum1

Dragonflies and damselfliesScore
Zigzag DarnerAeshna sitchensis3
Hine's EmeraldSomatochlora hineana2
Sphagnum SpriteNehalennia gracilis2
Forcipate EmeraldSomatochlora forcipata1
Subarctic DarnerAeshna subarctica1

Grasshoppers and alliesScore
Crackling Forest GrasshopperTrimerotropis verruculata1
Spotted-winged GrasshopperOrphulella pelidna1

Leafhoppers and true bugsScore
A LeafhopperLimotettix pseudosphagneticus1

Northern Long-eared BatMyotis septentrionalis2
Silver-haired BatLasionycteris noctivagans2
Big Brown BatEptesicus fuscus1
Little Brown BatMyotis lucifugus1
Water ShrewSorex palustris1

Blanding's TurtleEmydoidea blandingii1
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
Carex exilis Coast Sedge 3
Carex livida Livid Sedge 3
Drosera anglica English Sundew 2
Drosera linearis Linear-leaved Sundew 2
Eriophorum russeolum ssp. leiocarpum Russet Cotton-grass 3
Juncus stygius Bog Rush 2
Parnassia palustris Marsh Grass-of-Parnassus 2
Rhynchospora fusca Brown Beak-rush 3
Triantha glutinosa False Asphodel 2
Trichophorum cespitosum Tufted Bulrush 3
Triglochin palustris Slender Bog Arrow-grass 2


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

Map of the Ecological Landscapes of Wisconsin.

Ecological LandscapeOpportunity
Northern Lake Michigan CoastalMajor
North Central ForestImportant
Northeast SandsImportant
Northern HighlandImportant

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

North Central Forest

Several rich fens have been described from the northernmost portions of this Ecological Landscape. Additional survey work is needed here, especially on public lands.

Northeast Sands

Several small stands of this type have been documented on public lands in the Northeast Sands. "Rich" conifer forests (white cedar swamps) are very common in this Ecological Landscape, and additional survey work has a good chance of turning up new occurrences of "rich" open peatlands as well.

Northern Highland

"Rich fens" are seemingly an anomaly in this region of deep, acid outwash sands, but there are several good examples known from the Northern Highland-American Legion State Forest.

Northern Lake Michigan Coastal

All occurrences identified to date are on the Door Peninsula. Groundwater pollution is a significant threat in this Ecological Landscape, because of the nearness to the surface of the fractured, soluble bedrock.


Boreal Rich Fen Photos

Boreal Rich Fen Photo

Pickerel Pond The Ridges. Boreal rich fen community with twig-rush (Cladium mariscoides) common.

Photo by Emmet Judziewicz.

Boreal Rich Fen Photo

Boreal fen (dominated by wire-leaved sedge Carex lasiocarpa) near outlet of Sioux River.

Photo by Eric Epstein.

Boreal Rich Fen Photo

Boreal Rich Fen near Whisker Lake, Florence County.

Photo by Emmet Judziewicz.

Boreal Rich Fen Photo

Boreal rich fen at north end of Spread Lake. Vilas County.

Photo by Eric Epstein.

Boreal Rich Fen Photo

Boreal rich fen often occurs along calcareous seeps and springs within cedar swamps.

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: Wednesday, June 16, 2021