Print Report

M877 Dasiphora fruticosa - Carex lasiocarpa / Campylium stellatum Alkaline Fen Macrogroup

Type Concept Sentence: This alkaline fen macrogroup occurs on peatlands across the boreal regions of North America, extending south into subboreal regions of the Rocky Mountains, Great Lakes, and northeastern and north-central U.S. Sphagnum peatmoss and ericaceous shrubs are patchy to absent and brown mosses, broad-leaved non-ericaceous shrubs, and thin-leaved graminoids are common.


Common (Translated Scientific) Name: Shrubby cinquefoil - Woolly-fruit Sedge / Star Campylium Moss Alkaline Fen Macrogroup

Colloquial Name: North American Boreal & Subboreal Alkaline Fen

Hierarchy Level:  Macrogroup

Type Concept: This alkaline fen vegetation contains a mossy peat layer with depths typically exceeding 40 cm, and extends across the boreal regions of North America, extending south into subboreal regions of Alaska and the Yukon Territory, the Rocky Mountains, Great Lakes, and northeastern and north-central U.S. The vegetation may be graminoid-dominated, shrub-dominated, or a patchwork of the two, with broad-leaved non-ericaceous shrubs typically dominant. There is a discontinuous to absent layer of Sphagnum peatmoss, with brown mosses (Calliergon, Campylium, Drepanocladus, Tomentypnum, Scorpidium scorpioides) present to dominant. Broad-leaved non-ericaceous shrubs such as Alnus incana, Betula glandulosa, Betula pumila, Dasiphora fruticosa ssp. floribunda, Myrica gale, Rhamnus alnifolia, Salix barclayi (west), Salix candida, Salix maccalliana (west), and other Salix spp. exceed the cover of ericaceous shrubs, although some shore fens may be dominated by Chamaedaphne calyculata. Thin-leaved graminoids include especially Carex lasiocarpa, as well as Carex aquatilis (on peat), Carex diandra, Carex interior, Carex limosa, Carex livida, Eriophorum viridicarinatum, Muhlenbergia glomerata, Rhynchospora alba, and Trichophorum alpinum. A wide diversity of herbs is found, especially Equisetum fluviatile, Menyanthes trifoliata, Sarracenia purpurea, Solidago uliginosa (east), Triantha glutinosa, and Triglochin maritima. Other herbs include Comarum palustre and Calla palustris.

These fens develop in open basins where lateral groundwater flows through circumneutral to calcareous parent materials or causes calcareous upwellings, creating moderately to strongly alkaline conditions. They are found on level to gently sloping surfaces, or in closed wet depressions (sometimes as floating mats), and along wetland margins and lake- and rivershores. The shore fens are occasionally flooded, and so are included here because flooding tends to create moderately alkaline conditions. Peat deposits are composed primarily of partially decomposed brown mosses and sedges. Depth of peat exceeds 40 cm, separating this from similar wetlands that are non-peatlands. The water table is at or just above the surface.

In the subboreal regions of southeastern Canada and the northeastern United States, this macrogroup is typically found in glaciated settings, in pitted outwash or in kettle lakes associated with kettle-kame-moraine topography. The characteristic species include the shrubs Cornus amomum, Cornus racemosa, Cornus sericea, Dasiphora fruticosa ssp. floribunda, prairie grasses such as Andropogon gerardii and Spartina pectinata, sedges including Carex flava, Carex sterilis, Carex prairea, and other graminoids such as Trichophorum alpinum, and forbs such as Packera aurea, Symplocarpus foetidus, Triantha glutinosa, and Lobelia kalmii. Less commonly, Cladium mariscoides may be a dominant.

In the western boreal regions of North America, this macrogroup occurs in shallow depressions and basins, pond margins, and thermokarst pits with an open hydrologic regime. Fens are nutrient-rich and have a thick peat layer that may be floating or submerged. Standing water is usually present. They are most abundant in areas of limestone bedrock, and widely scattered in areas where calcareous substrates are scarce.

Diagnostic Characteristics: This type contains a peat layer of partially decomposed sedges and brown mosses with depths exceeding 40 cm. Dwarf-shrubs and thin-leaved graminoids are >25%, stunted (scrub) trees <2 m with variable cover; otherwise trees <10% cover. There is a discontinuous to absent layer of Sphagnum peatmoss (<80% cover), with brown mosses (Aulacomnium palustre, Calliergon, Campylium, Drepanocladus, Tomentypnum, Scorpidium scorpioides) present to dominant. Broad-leaved non-ericaceous shrubs (Alnus incana, Betula glandulosa, Betula pumila, Dasiphora fruticosa ssp. floribunda, Myrica gale, Rhamnus alnifolia, Salix spp.) exceed cover of ericaceous shrubs, although some shore fens may be dominated by Chamaedaphne calyculata. Thin-leaved graminoids include Carex lasiocarpa, Carex limosa, Carex livida, Carex interior, Eriophorum viridicarinatum, Muhlenbergia glomerata, Trichophorum alpinum, and together these graminoids exceed the cover of acidic peatland graminoids indicators (Carex magellanica ssp. irrigua, Carex oligosperma, Eriophorum vaginatum, Eriophorum virginicum, Scheuchzeria palustris).

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This macrogroup excludes "forested fens," which have trees >2 m and >10% cover, and are treated here as rich swamps [see ~North American Boreal Conifer Poor Swamp Macrogroup (M299)$$. Both ~North American Boreal & Subboreal Bog & Acidic Fen Macrogroup (M876)$$ and this macrogroup (M877) are organic wetlands or peatlands in the Canadian wetland classification system. The Canadian system separates bogs from fens based on the influence of nutrient-rich groundwater in fens, which is missing in bogs. Here, we include poor fens with bogs, because they tend to be acidic and have a dominance of Sphagnum spp. in the bryophyte layer. M877 includes fens that have been classed as medium-rich to extremely rich as these have many species in common (Vitt and Chee 1990) and the bryophyte layer tends to lack the dominance of Sphagnum spp. found in bogs and poor fens.

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: This macrogroup contains a moss peat layer with depths exceeding 40 cm. Dwarf-shrubs and thin-leaved graminoids are >25%, stunted (scrub) trees <2 m with variable cover; otherwise trees <10%. There is a discontinuous to absent layer of Sphagnum peatmoss (<80% cover), with brown mosses present to dominant. Ericaceous dwarf-shrubs are typically minor, with broad-leaved shrubs dominant. Broad-leaved non-ericaceous shrubs exceed cover of ericaceous shrubs (>50%), although some shore fens may be more ericaceous-dominated. Thin-leaved graminoids are common. The tree layer is rare to absent (though some scrubby <2 m tall treed fens may fall within this type, with the tree layer usually dominated by Larix laricina).

The landscape morphology of alkaline peatlands is often very striking. A variety of approaches has been taken to describe these forms: in Maine, see Davis and Anderson (2001); in Canada, see National Wetlands Working Group (1988); and in Minnesota, see Glaser (1992a). In Canada, bog and fen peatlands each have their own set of forms. In Minnesota, Glaser treats bogs and fens together as part of larger patterned peatland complexes (mire complexes). Particularly distinctive are the ribbed bogs or fens in which a pattern of narrow (2- to 3-m wide), low (less than 1 m deep) ridges are oriented at right angles to the direction of the drainage (National Wetlands Working Group 1988). Wet pools or depressions occur between the ridges. These patterned peatlands may include string bog, Atlantic ribbed fen, or northern ribbed fen (National Wetlands Working Group 1988). They develop almost entirely north of 46°N latitude in east-central Canada and the adjacent U.S. They are minerotrophic peatlands in which the vegetation has developed into a pattern of strings (raised, usually linear features, and more acidic) and flarks (wet depressions separating the strings, and less acidic). Bedrock or other substrate influences create circumneutral to calcareous conditions. In circumneutral areas, some of the more typical bog heaths may codominate with deciduous alkaline shrubs. Alkaline peatlands usually develop in open basins and flat plains, and the patterned portion may occupy only a fraction of the entire peatland. The edge of the basin may be shallow to deep peat over a sloping substrate, where seepage waters provide nutrients.

Floristics: Broad-leaved shrubs (Alnus incana, Betula glandulosa, Betula michauxii, Betula pumila, Dasiphora fruticosa ssp. floribunda, Myrica gale, Rhamnus alnifolia, Salix spp.) are dominant to minor, and ericaceous dwarf-shrubs, such as Andromeda polifolia, Vaccinium oxycoccos, and Kalmia polifolia are minor, but Chamaedaphne calyculata is occasionally dominant. Thin-leaved graminoids include especially Carex lasiocarpa, but also Carex aquatilis (on peat) Carex chordorrhiza, Carex interior, Carex limosa, Carex livida, Eriophorum viridicarinatum, Muhlenbergia glomerata, Rhynchospora alba, and Trichophorum alpinum. A wide diversity of herbs is found, especially Drosera rotundifolia, Equisetum fluviatile, Menyanthes trifoliata, Sarracenia purpurea, Triantha glutinosa (= Tofieldia glutinosa), and Triglochin maritima. Species diversity is typically high (though shore fens may be low). Less commonly, Calamagrostis canadensis and Equisetum fluviatile may be present. Mosses include the brown mosses Campylium stellatum, Limprichtia revolvens (= Drepanocladus revolvens), Scorpidium scorpioides, and Tomentypnum nitens. Sphagnum spp. are patchy to absent, and may include Sphagnum russowii, Sphagnum squarrosum and Sphagnum warnstorfii, among others (Gignac 1991, Vitt et al. 1995, Harris et al. 1996, Minnesota DNR 2003).

In the subboreal regions of southeastern Canada and the northeastern and north-central United States, characteristic species include the shrubs Cornus amomum, Cornus racemosa, Cornus sericea, Dasiphora fruticosa ssp. floribunda, prairie grasses such as Andropogon gerardii and Spartina pectinata, sedges including Carex flava, Carex prairea, Carex sterilis, and other graminoids such as Trichophorum alpinum, and forbs such as Packera aurea, Triantha glutinosa, and Lobelia kalmii. In the western part of its range, Carex lasiocarpa, Eriophorum angustifolium ssp. angustifolium (= Eriophorum polystachion), Parnassia glauca, Eleocharis compressa, and Symphyotrichum boreale (= Aster borealis) may be common. Less commonly, Cladium mariscoides may be a dominant.

Trees are typically sparse in this macrogroup, though they may extend inward from natural wooded wetland borders. Common trees, even though stunted or scattered, include Larix laricina and (in the east) Thuja occidentalis.

Dynamics:  In boreal wetlands, the general successional trend is often suggested to go from marsh to fen to treed bog. Although often true (Klinger and Short 1996), succession is not necessarily directional, and environmental conditions such as nutrient content and abundance of groundwater may prevent fens from developing into bogs (Zoltai et al. 1988). Succession may begin in ponds or low-lying wetlands formed by processes such as glacial recession and floodplain dynamics (oxbows). An organic root mat typically develops and is either anchored to the mineral soil or floating on water such as a pond''s edge. Over time, peat-forming mosses and sedges may fill in the basin. As the peat layer develops, low and/or dwarf-shrubs become established. Dwarf-trees may establish on the well-developed peat and also around the margin of the peatland (e.g., Klein et al. 2005).

In the subboreal regions, some fens are kept open by grazing, and succession to heavier shrub cover may occur in the absence of grazing. The role of fire disturbance in fens needs further review.

Environmental Description:  Soil/substrate/hydrology: These fens develop where lateral groundwater flows through circumneutral to calcareous parent materials or through calcareous upwellings that create moderately to strongly alkaline, saturated conditions. They are found on level to gently sloping surfaces, or in closed wet depressions (sometimes as floating mats), and along wetland margins and lake- and rivershores The shore fens are occasionally flooded, and so are included here because flooding tends to create moderately alkaline conditions. In the western boreal regions, these occur in shallow depressions and basins, pond margins, and thermokarst pits with an open hydrologic regime. Fens are nutrient-rich and have a thick peat layer that may be floating or submerged. Standing water is usually present. They are most abundant in areas of limestone bedrock, and widely scattered in areas where calcareous substrates are scarce.

Geographic Range: This macrogroup is found in scattered locations of boreal New England and Canada west to the Great Lakes and northern Minnesota and extends across the western boreal regions of Canada and the U.S., with occurrences within inland British Columbia, western Alberta, and north into Alaska and Yukon Territory.

Nations: CA,US

States/Provinces:  AB, AK, BC, CO, CT, ID, IL, IN, MA, MB, ME, MI, MN, MT, NB, ND, NH, NJ, NS, NT, NY, OH, ON, OR, PA, PE?, QC, RI, SD, SK, VT, WA, WI, WV, WY, YT




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: = Fen Wetland Class (National Wetlands Working Group 1988)
< Peatlands (Mitsch and Gosselink 2000)

Concept Author(s): National Wetlands Working Group (1988)

Author of Description: D. Faber-Langendoen, G. Kittel, M. Reid, M. Hall, K. Boggs, T. Boucher, S.C. Gawler

Acknowledgements: No Data Available

Version Date: 03-29-17

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