T Open Peatlands he allure and mystique of peatlands has attracted people for millennia. Well- preserved “bog bodies” up to 8,000 years old have been found in peatlands from northern Europe to Florida, attesting to an early human relationship to peatlands and revealing religious and cultural practices ranging from human sacrifice to well-organized social structure. In more recent times, naturalists and ecologists have conducted numerous studies of peatland flora, fauna, ecology, and paleoecology. Quite simply, peatlands are wetlands that accumulate peat, a soil type consisting of partially decomposed organic matter. They occur primarily in northern cold-temper- ate and boreal regions of the world, where moist conditions result from annual precipitation exceeding evapotranspiration. Peatlands are permanently saturated with water at or near the soil surface, creating a nearly anaerobic soil environment with limited biological activity. Under these soil conditions, plant growth exceeds plant decomposition, and layers of peat accumulate annually. Two main types of peatlands are commonly distinguished. Bogs are peatlands with slightly raised surfaces that receive most of their water and nutrients from precipitation and are therefore referred to as being ombrotrophic. They have acidic waters that are poor in minerals and nutrients. Bogs are dominated by species of the moss genus Sphagnum, heath shrubs, and in some areas, black spruce. Fens, in contrast, have slightly acidic to slightly basic, mineral-rich waters from groundwater discharge and seepage. Fens may be flat or gently sloping and are dominated by sedges, grasses, and “brown mosses” (non-sphagnum mosses). There is clearly a continuum in the variation between bogs and fens in nature. The following peatland community profiles are presented in an order that roughly reflects this continuum, beginning with ombrotrophic Dwarf Shrub Bog, progressing through several peatland types that receive some mineral enrichment, and ending with Rich Fen, our most enriched peatland type. As mentioned above, decomposition of organic material is generally slow in peatlands due to the cool and nearly anaerobic soil conditions. There is, however, considerable variation in the rate of decomposition and the resulting types of peat found in peatlands along the gradient from Dwarf Shrub Bog to Rich Fen. The acidity or basicity of peatland water is measured using the pH scale. This scale translates hydrogen ion concentration of the water or solution being measured into numbers ranging from 1 to 14, where 7 is neutral, values below 7 are considered acidic, and values above 7 are considered basic. The very acidic waters found in bogs contribute to the slow activity of soil microorganisms and an overall slow rate of peat decomposi- tion. Bog water is usually stagnant, whereas the surface water in fens moves slowly across the peatland surface or through the upper layers of peat. This results in slightly higher oxygen concentrations in fen waters and therefore greater peat decomposition compared to bogs. Another important factor affecting peat types is the vegetation of the Open Peatlands / 311
Transcript
Introduction / 311
T
Open Peatlands
he allure and mystique of peatlands has attracted people for millennia. Well-preserved “bog bodies” up to 8,000 years old have been found in peatlandsfrom northern Europe to Florida, attesting to an early human relationship to
peatlands and revealing religious and cultural practices ranging from human sacrificeto well-organized social structure. In more recent times, naturalists and ecologists haveconducted numerous studies of peatland flora, fauna, ecology, and paleoecology.
Quite simply, peatlands are wetlands that accumulate peat, a soil type consistingof partially decomposed organic matter. They occur primarily in northern cold-temper-ate and boreal regions of the world, where moist conditions result from annualprecipitation exceeding evapotranspiration. Peatlands are permanently saturated withwater at or near the soil surface, creating a nearly anaerobic soil environment withlimited biological activity. Under these soil conditions, plant growth exceeds plantdecomposition, and layers of peat accumulate annually.
Two main types of peatlands are commonly distinguished. Bogs are peatlands withslightly raised surfaces that receive most of their water and nutrients from precipitationand are therefore referred to as being ombrotrophic. They have acidic waters that arepoor in minerals and nutrients. Bogs are dominated by species of the moss genusSphagnum, heath shrubs, and in some areas, black spruce. Fens, in contrast, haveslightly acidic to slightly basic, mineral-rich waters from groundwater discharge andseepage. Fens may be flat or gently sloping and are dominated by sedges, grasses,and “brown mosses” (non-sphagnum mosses). There is clearly a continuum in thevariation between bogs and fens in nature. The following peatland community profilesare presented in an order that roughly reflects this continuum, beginning withombrotrophic Dwarf Shrub Bog, progressing through several peatland types that receivesome mineral enrichment, and ending with Rich Fen, our most enriched peatland type.
As mentioned above, decomposition of organic material is generally slow inpeatlands due to the cool and nearly anaerobic soil conditions. There is, however,considerable variation in the rate of decomposition and the resulting types of peatfound in peatlands along the gradient from Dwarf Shrub Bog to Rich Fen. The acidityor basicity of peatland water is measured using the pH scale. This scale translateshydrogen ion concentration of the water or solution being measured into numbersranging from 1 to 14, where 7 is neutral, values below 7 are considered acidic, andvalues above 7 are considered basic. The very acidic waters found in bogs contributeto the slow activity of soil microorganisms and an overall slow rate of peat decomposi-tion. Bog water is usually stagnant, whereas the surface water in fens moves slowlyacross the peatland surface or through the upper layers of peat. This results in slightlyhigher oxygen concentrations in fen waters and therefore greater peat decompositioncompared to bogs. Another important factor affecting peat types is the vegetation of the
Peatlands / 311Open Peatlands / 311
312 / Wetland, Woodland, Wildland
peatland. Dead sphagnum moss is a dominant component of the poorly decomposed,tan-colored, fibric peat found in bogs. Remains of sedges are prominent in the moder-ately decomposed, dark reddish brown, hemic peat of many fens. Sapric peat is darkbrown to black and is so well decomposed that plant remains are not recognizable.
A single genus of plants deserves special attention in building an understanding ofbogs and fens. There are 29 species of sphagnum moss documented in Vermont. Manyof these species are dominant in Dwarf Shrub Bogs and Poor Fens and play manyimportant roles in shaping peatland ecology. Live sphagnum moss and peat derivedfrom sphagnum have an enormous capacity to hold water due to the structure of theleaves and leaf cells. This water holding capacity results in creation of a bog water tableraised above the regional water table and contributes to the process of paludification,in which peatlands expand horizontally over time as peat accumulates and impedesdrainage. Sphagnum also has the ability to remove mineral cations from solution andrelease hydrogen ions, thereby acidifying the environment in which it grows. Sphagnumpeat is an excellent thermal insulator, and ice may persist in hummocks well into June.The result for many bog plants is a condition of water stress, as their roots may befrozen at the same time that the leaves and stems are functioning under spring and earlysummer temperatures. The reader is directed to texts by Crum (1988) and McQueen(1990) listed below for a more comprehensive treatment of sphagnum ecology.
Peatlands contain an amazing record of past vegetation and climate changes.Vermont’s peatlands have been forming since the retreat of the glaciers some 13,500years ago. Over this period, each thin layer of annual peat accumulation has storedfragments of plants that grew in the wetland, as well as pollen from peatland plants andnearby forests. By taking cores of peat, paleoecologists are able to date the time atwhich specific layers were deposited and analyze the peat composition to determinewhat plants grew in the vicinity at that time. Understanding the ecology of individualspecies identified provides a basis for interpreting the vegetation and climate at aparticular time. These paleoecological records have revealed that Vermont was firstcolonized by tundra, followed by the spread of black spruce and birch forests begin-ning about 11,000 years ago. Northern Hardwood species began colonizing the lowerelevations of the area approximately 8,000 years ago. There is also strong evidence thatthere was a period of much warmer climate about 6,000 years ago that is reflected byabundant oak pollen in the paleoecological record.
Selected References and Further ReadingJohnson, C. 1985. Bogs of the Northeast. University Press of New England, Hanover.Crum, H. 1988. A Focus on Peatlands and Peat Mosses. University of Michigan Press,
Ann Arbor.McQueen, C. 1990. Field Guide to the Peat Mosses of Boreal North America. University
Press of New England, Hanover.Damman, A. and T. French. 1987. The ecology of peat bogs of the glaciated
northeastern United States: a community profile. U.S. Fish and Wildlife ServiceBiological Report 85.
Peatland Natural CommunitiesRead the short descriptions that follow and choose the community that fits best.
Then go to the page indicated and read the full community profile to confirm yourdecision.
Dwarf Shrub Bog: These bogs are open, acid peatlands dominated by heath shrubs(leatherleaf, bog laurel, sheep laurel, and Labrador tea) and sphagnum moss. Scattered,stunted black spruce and tamarack trees cover less than 25 percent of the ground.Found in cold climate areas. Deep sphagnum peat is permanently saturated. Go topage 314.
Black Spruce Woodland Bog: Stunted black spruce trees cover 25 to 60 percent ofthe ground over heath shrubs and sphagnum moss. Found in cold climate areas. Peat isdeep and dominated by remains of sphagnum moss. Go to page 318.
Pitch Pine Woodland Bog: Pitch pine forms an open canopy (25 to 60 percentcover) over rhodora, heath shrubs, and sphagnum moss. This community is knownonly from Maquam Bog at the mouth of the Missisquoi River. Go to page 321.
Alpine Peatland: This community is found only on the highest peaks of the GreenMountains (above 3,500 feet). It has characteristics of both bog and poor fen, but isdistinguished by its high elevation and presence of alpine bilberry, black crowberry,Bigelow’s sedge, and deer-hair sedge. Peat is shallow over bedrock. Go to page 324.
Poor Fen: These fens are open, acid peatlands dominated by sphagnum mosses,sedges, and heath shrubs. There is some mineral enrichment of surface waters in thehollows, as indicated by the presence of bog bean, mud sedge, white beakrush, andhairy-fruited sedge. Peat is deep and made up of sphagnum moss and sedge remains.Go to page 327.
Intermediate Fen: These fens are open, slightly acid to neutral peatlands dominatedby tall sedges, non-sphagnum mosses, and a sparse to moderate cover of shrubs.Hairy-fruited sedge is typically dominant and water sedge, twig rush, bog-bean, andsweet gale are characteristic. The peat is deep, saturated, and composed of sedgeremains. Go to page 330.
Rich Fen: These fens are similar to Intermediate Fen but typically have shallowersedge peat and more mineral-enriched surface waters. A gentle slope of the peatlandmay be evident. Sedges and non-sphagnum mosses dominate, including inland sedge,porcupine sedge, yellow sedge, and the moss starry campylium. Red-osier dogwood,shrubby cinquefoil, and alder-leaved buckthorn are characteristic shrubs. Go topage 333.
HOW TO IDENTIFY�
Open Peatlands / 313
314 / Wetland, Woodland, Wildland
ECOLOGY AND PHYSICAL SETTINGEntering a bog for the first time is likely to be a long-
remembered experience. There is an otherworldly characterto bogs that is unlike any other part of our Vermontlandscape. They are quiet places with soft, spongy groundunderfoot and typically have dense conifer forests surround-ing them. Bogs are open but may have a few scattered,highly stunted trees. Early summer can bring a profusionof flowers on the low shrubs and songs of birds commonlyfound much farther north. Insectivorous plants, like pitcherplant and sundew, are well adapted to the low nutrientenvironments of bogs and are a common occurrence.
Dwarf Shrub Bogs are open peatlands with acidic water(pH of 3.5 to 5.0) that is very low in dissolved mineralsand nutrients. Bogs are referred to as being ombrotrophicif they receive water and nutrients only from precipitation.Ombrotrophic bogs have a slightly raised peat surface anda water table that generally remains just below the peatsurface but elevated above the local water table of sur-rounding wetlands or uplands. Most Dwarf Shrub Bogs inVermont are not entirely ombrotrophic, as they receivesome mineral enrichment from surface or groundwater, atleast at their margins. The permanently saturated, acidconditions severely limit decomposition in bogs, resulting insignificant accumulation of poorly decomposed sphagnumpeat. Dwarf Shrub Bogs typically have well-developedmicrotopography, with tall hummocks and moist hollows.
Across boreal regions, bogs and other peatland typescover extensive areas of the landscape. In Vermont, mostof our bogs are relatively small (1 to 600 acres) and occurin isolated kettlehole basins and as inclusions in largerwetland complexes. Kettlehole basins are depressions left
DISTRIBUTION/ABUNDANCEDwarf shrub bogs
occur throughout Vermontbut are more common inthe cooler regions of thestate. Similar communitiesare found throughout theNortheast, Midwest, andadjacent Canada.
DWARF SHRUB BOG
Profile / 315
in the ground from partially buried iceblocks that melted after the retreat of theglaciers. In these settings there is commonlya floating bog mat over open water in thecenter of the basin. In cases where bogsoccur as part of larger wetland systems,they are typically in central portions of thecomplex where peat has developed tosufficient depth to effectively isolate thebog surface from the influence of mineral-rich ground or surface water movement.Dwarf Shrub Bogs commonly grade intoBlack Spruce Woodland Bogs, which inturn may grade into Black Spruce Swamps.Dwarf Shrub Bogs may also grade intoPoor Fens in areas where there is someseepage of mineral-enriched groundwater.When occurring in basins surrounded byupland forests, Dwarf Shrub Bogs aretypically bordered by a narrow, wet, tallshrub-dominated strip known as a laggzone or moat. Water accumulates in thislagg zone as a result of drainage from thesurrounding uplands and the slightly raisedsurface of the bog. The water in the laggzone may be stagnant or slowly moving,but it is enriched with dissolved mineralscompared to the open bog.
VEGETATIONThe dominant vegetation of bogs is peat
moss of the genus Sphagnum, which formsa continuous carpet over hummocks andhollows, and from which other plants grow.Dwarf Shrub Bogs are open peatlands withless than 25 percent cover of tall shrubs ortrees. In many cases trees and tall shrubsare nearly absent. Dwarf shrubs aregenerally common and may form a dense,low woody layer or a more sparse cover.Sedges are also common and grow in bothhummocks and hollows.
Many species of sphagnum typicallyoccur in any one bog, but there are distinct,easily observed patterns to the distributionof these species. One such pattern can beobserved in the species zonation thatoccurs from dry hummock tops to themoist hollow bottoms two to three feetbelow. The brown-colored Sphagnum
fuscum dominates hummock tops, with aprogression down the hummock sides ofSphagnum capillifolium, Sphagnummagellanicum, Sphagnum angustifolium,and Sphagnum fallax. Sphagnumcuspidatum occurs in the wetter hollowswith some standing water. The tops ofthese raised hummocks are ombrotrophicenvironments, even if the bogs in whichthey occur are not truly ombrotrophic.
Low heath shrubs dominate thehummocks of many bogs, with commonspecies including leatherleaf, bog laurel,Labrador tea, sheep laurel, and bogrosemary. Low plants of the hummocksinclude small cranberry, three-seededsedge, few-flowered sedge, and hare’s tailcottongrass. Pitcher plant and round-leavedsundew are also common. White beakrushis more common in the moist hollows,especially with some enrichment. Onhummocks there may be scattered, stuntedblack spruce and tamarack trees. Lichensmay also be common.
DWARF SHRUB BOG
Bog laurel – Kalmia polifolia
Open Peatlands / 315
316 / Wetland, Woodland, Wildland
ANIMALSSome breeding birds of Dwarf Shrub
Bogs include Lincoln’s sparrow, commonyellowthroat, and rusty blackbird. Northernharriers also occasionally nest in thesebogs. The rare four-toed salamander andspotted turtle may both be found in bogsthat have an associated pool, especially inthe warmer regions of the state. Somecharacteristic invertebrates include the bogcopper butterfly, the bog tiger moth, andseveralspecies ofdragonfliesanddamselflies.Southernboglemmings,meadowvoles, andmaskedshrews mayall be foundin DwarfShrub Bogs.
VARIANTSNo
variants arecurrently recognized for this community inVermont. However, within our Dwarf ShrubBogs there are recognizable variations incommunity composition and structure thatare known as sphagnum lawns, mud-bottoms, and sedge/moss lawns. Withadditional quantitative data we may wantto recognize these variations and others asdistinct communities within peatlandecosystems.
RELATED COMMUNITIESBlack Spruce Woodland Bog: This
community has an open, stunted canopy(25 to 60 percent cover) dominated byblack spruce, with abundant heath shrubsand sphagnum moss. Dwarf Shrub Bogsoften grade into Black Spruce WoodlandBogs.
DWARF SHRUB BOG
Poor Fen: This community receivessome mineral enrichment from groundwa-ter seepage or association with the openwater of ponds. Sphagnum and heathshrubs are common, as are sedges like mudsedge and white beakrush, and indicatorsof enrichment like bog-bean.
CONSERVATION STATUS AND
MANAGEMENT CONSIDERATIONSDwarf Shrub Bogs are considered rare in
Vermont, bothbecause thereare relativelyfew sitesknown andbecause thetotal acreageof bogs in thestate is low.There are,however,several highqualityexamplesprotected onland ownedby the publicor byconservation
organizations. The integrity of bogs can bethreatened by significant changes inadjacent land use that result in increases inrunoff and changes in water quality, suchas development and clear-cutting. DwarfShrub Bogs are also susceptible to tram-pling and compaction from heavy humanuse. Development of boardwalks atselected sites and restricted access at othersites may be necessary.
PLACES TO VISITMoose Bog, Wenlock Wildlife Management
Area, Ferdinand, Vermont Departmentof Fish and Wildlife (VDFW)
FURTHER READINGJohnson, C. 1985. Bogs of the Northeast.
University Press of New England,Hanover.
Crum, H. 1988. A Focus on Peatlands andPeat Mosses. University of MichiganPress, Ann Arbor.
McQueen, C. 1990. Field Guide to the PeatMosses of Boreal North America.University Press of New England,Hanover.
Damman, A. and T. French. 1987. Theecology of peat bogs of the glaciatednortheastern United States: a communityprofile. U.S. Fish and Wildlife ServiceBiological Report 85.
Open Peatlands / 317
DWARF SHRUB BOG
318 / Wetland, Woodland, Wildland
ECOLOGY AND PHYSICAL SETTINGBlack Spruce Woodland Bogs are acidic, nutrient and
mineral-poor peatlands with open canopies of black spruce.Although the Vermont examples of this community type aregenerally under 50 acres, closely related variations coverextensive areas of the boreal landscape, where it is oftenreferred to as black spruce muskeg. In Vermont, BlackSpruce Woodland Bogs are transitional between DwarfShrub Bogs and Black Spruce Swamps and often occur inassociation with one or both of these communities. Thiscommunity may also occur in association with Poor Fens,and in these cases there may be slight mineral enrichmentthat alters the typical vegetation of the Black SpruceWoodland Bog.
Like Dwarf Shrub Bogs, Black Spruce Woodland Bogsoccur in kettlehole basins and as part of larger peatlandsystems. The poorly decomposed sphagnum and woodypeat is generally greater than three feet deep, and maybe over ten feet deep. These organic soils are saturatedthroughout the year. Hummocks and hollows are welldeveloped, but there is seldom any standing water in themoist hollows. Like Dwarf Shrub Bogs, Black SpruceWoodland Bogs are found in the colder regions of thestate or in depressions that receive cold air drainage.
VEGETATIONThis woodland community has scattered, stunted black
spruce trees that are generally under 30 feet tall and forman open canopy (25 to 60 percent cover). In this peatlandsetting with a substrate low in oxygen and minerals, blackspruce grows slowly and many trees have a characteristiclollipop-shaped top. Black spruce dominates the tall shrublayer as well, although tamarack may also be present. Low,heath shrubs are abundant, especially Labrador tea and
DISTRIBUTION/ABUNDANCEBlack Spruce Woodland
Bogs are found in the coolerregions of Vermont. Closelyrelated communities arewidespread across boreallatitudes, and similarcommunities occur as farsouth as Pennsylvania andNew Jersey.
BLACK SPRUCE WOODLAND BOG
Profile / 319
leatherleaf, with lesser amounts of sheeplaurel, bog laurel, blueberries, and rhodora,all of which are mixed with small blackspruce. In areas with a slight amount ofmineral enrichment, one is more likely tofind tall shrubs such as mountain-holly,wild raisin, and winterberry holly. High-bush blueberry and black huckleberry mayoccur in some examples in the southernregions of Vermont, where rhodora andLabrador tea may be absent.
Raised hummocks and low hollows areall carpeted by sphagnum moss, with thetypical species zonation from hummock topto hollow bottom being Sphagnum fuscum,Sphagnum capillifolium, Sphagnummagellanicum, Sphagnum angustifolium,and Sphagnum fallax. Schreber’s moss isvery common in this community, as is thehaircap moss Polytrichum strictum. Smallcranberry is typically present, as are three-seeded sedge, round-leaved sundew, hare’stail cottongrass, and creeping snowberry.
ANIMALSSome breeding birds of Black Spruce
Woodland Bogs include Canada warbler,Nashville warbler, mourning warbler,magnolia warbler, common yellowthroat,Lincoln’s sparrow, yellow-bellied flycatcher,and olive-sided flycatcher. In northeasternVermont, spruce grouse, black-backedwoodpecker, boreal chickadee, palmwarbler, and gray jay may also be present.Southern bog lemmings, southern red-backed voles, and masked shrews may allbe found in Black Spruce Woodland Bogs.
VARIANTSNone recognized at this time.
RELATED COMMUNITIESDwarf Shrub Bog: This open peatland
community is dominated by sphagnummoss and heath shrubs, with less than 25percent cover of stunted black spruce ortamarack.
Black Spruce Swamp: This forestedswamp community has greater than 60percent cover of black spruce and othertrees. Black Spruce Swamps typically aresomewhat enriched through contact withmineral soils or runoff and have shallower,
more decomposed organic soils than inBlack Spruce Woodland Bogs.
CONSERVATION STATUS AND
MANAGEMENT CONSIDERATIONSBlack Spruce Woodland Bogs are rare in
Vermont and most of our examples aresmall. Like Dwarf Shrub Bog, this commu-nity is threatened by alterations in thesurrounding watershed that result inchanges in the quality or quantity of surfacewater runoff. Clearcutting and developmentare examples of activities that are known toalter runoff characteristics. The vegetationand peat of Black Spruce Woodland Bogs isalso susceptible to trampling by over-use.Designated access areas and restrictedaccess to some sites is necessary to protectthe integrity of the community.
PLACES TO VISITLake Carmi Bog, Lake Carmi State Park,
Franklin, Vermont Department ofForests, Parks, and Recreation (VDFPR)
Moose Bog, Wenlock Wildlife ManagementArea, Ferdinand, Vermont Departmentof Fish and Wildlife (VDFW)
Morristown Bog, Morristown, VDFPRMollie Beattie Bog, Lewis, U.S. Fish and
Wildlife Service
SELECTED REFERENCES AND FURTHER
READINGJohnson, C. 1985. Bogs of the Northeast.
University Press of New England,Hanover.
Crum, H. 1988. A Focus on Peatlands andPeat Mosses. University of MichiganPress, Ann Arbor.
McQueen, C. 1990. Field Guide to the PeatMosses of Boreal North America.University Press of New England,Hanover.
Damman, A. and T. French. 1987. Theecology of peat bogs of the glaciatednortheastern United States: a communityprofile. U.S. Fish and Wildlife ServiceBiological Report 85.
ECOLOGY AND PHYSICAL SETTINGOnly one example of this community is known in
Vermont, but it is very large and very interesting, and assuch deserves separate mention and description. MaquamBog is an 890-acre open peatland located near the mouthof the Missisquoi River. Pitch Pine Woodland Bog is onlyone of several natural communities occurring at MaquamBog, with the majority of the peatland best classified asDwarf Shrub Bog. Pitch Pine occurs in groves that arescattered across the open peatland surface. This peatlandhas a slightly raised center and a surface of irregularhummocks and hollows. Peat depths vary from 2.5 feet tonearly 8 feet, and the peat is generally fibrous and woody atthe surface and grades to muck at the base. The peatlandwater is acidic, with pH ranging from 3.6 to 4.5. Beneath thepeat are deltaic sand and silt deposits, reflecting an earliercourse of the Missisquoi River.
The ecology and vegetation patterns of Maquam Boghave been related to past fires and flooding (Strimbeck1988). Fires have repeatedly burned across the surface ofthe peatland, and lake levels have been shown to inundatethe peatland every other year on average. Strimbeckhypothesized that periodic fires reduce the cover of tallshrubs, exclude fire intolerant species, and promotereproduction and maintenance of pitch pine in the peatland.Gradients in pH and nutrients in the peatland may berelated to lake level fluctuations, thereby influencing plantspecies distribution.
VEGETATIONThe Pitch Pine Woodland Bog community at Maquam
Bog is characterized by an open canopy of pitch pine,typically less than 60 percent cover. Gray birch is abundant
DISTRIBUTION/ABUNDANCEThere is only one known
example of this communitytype in Vermont. It is locatedin northwestern Vermont atthe mouth of the MissisquoiRiver. Similar communitiesoccur in the Atlantic coastalplain from Maine south toNew Jersey.
PITCH PINE WOODLAND BOG
Open Peatlands / 321
322 / Wetland, Woodland, Wildland
Maquam Bog viewed from the air.
in some areas, and there are scattered,stunted trees of black spruce and redmaple.
Both the open portions of Maquam Bogand the Pitch Pine Woodland Bog aredominated by low shrubs. Rhodora isespecially abundant and a sea of pinkflowers adorns the bog in late May to earlyJune. Other abundant low shrubs includeleatherleaf, black chokeberry, sheep laurel,bog laurel, Labrador tea, and sweet gale.Patches of highbush blueberry andmountain-holly are common, and wildraisin is scattered in the peatland. Bothlarge and small cranberries are common.
Several species of sphagnum carpet thehummocks and hollows under the lowshrubs and open canopy of pitch pine,including Sphagnum fuscum, Sphagnummagellanicum, Sphagnum capillifolium,and Sphagnum angustifolium. Sedges areabundant in some areas and include hare’stail cottongrass, few-seeded sedge, andVirginia cottongrass. Three-leaved falseSolomon’s seal and the rare Virginia chainfern are also locally common.
ANIMALSRed-tailed hawk and blue-winged teal
are known to nest in Maquam Bog. Otherpotential breeding birds in this communityinclude northern harrier and short-earedowl, both of which have been observed atthe bog (Strimbeck 1988), as well as swampsparrow, common yellowthroat, northernwaterthrush, and common snipe. Mammalsknown to use the bog are meadow vole,white-tailed deer, and red squirrel.
VARIANTSNone recognized at this time.
RELATED COMMUNITIESDwarf Shrub Bog: This acid, open
peatland type shares many species ofsphagnum and heath shrubs with PitchPine Woodland Bog, but lacks pitch pineand is not dominated by rhodora.
PITCH PINE WOODLAND BOG
Profile / 323
CHARACTERISTIC PLANTS
TREESAbundant SpeciesPitch pine – Pinus rigidaOccasional to Locally Abundant SpeciesGray birch – Betula populifoliaBlack spruce – Picea marianaRed maple – Acer rubrum
RARE AND UNCOMMON PLANTSVirginia chain fern – Woodwardia virginica
PITCH PINE WOODLAND BOG
CONSERVATION STATUS AND
MANAGEMENT CONSIDERATIONSMaquam Bog is the only known
example of this rare community inVermont. Maquam Bog is owned by theU.S. Fish and Wildlife Service, as part ofthe Missisquoi National Wildlife Refuge.This highly significant peatland is wellprotected in public ownership under amanagement plan that maintains ecologicalprocesses. Alteration of natural water levelfluctuations in Lake Champlain could posea significant threat to this community,affecting the degree of mineral and nutrientenrichment in the peatland. Managementof Maquam Bog with a long term goal ofmaintaining natural disturbance regimeswill include allowing lightning-ignited firesto proceed, and may require carefullyplanned prescribed burns on portions ofthe peatland.
PLACES TO VISITMaquam Bog, Missisquoi National Wildlife
Refuge, Swanton, U.S. Fish and WildlifeService
SELECTED REFERENCES AND FURTHER
READINGStrimbeck, G. R. 1988. Fire, flood, and
famine: pattern and process in a lakesidebog. University of Vermont FieldNaturalist Program.
Gershman, M. 1987. A study of the Maquampeatland, Swanton, Vermont. Universityof Vermont Field Naturalist Program.
Open Peatlands / 323
324 / Wetland, Woodland, Wildland
ECOLOGY AND PHYSICAL SETTINGAlpine Peatlands in Vermont are all very small and are
restricted to the highest elevations of the Green Mountains,primarily Mount Mansfield. The climate here is intense, withfrequent fog, high winds, cold temperatures, and thegreatest precipitation of anywhere in the state (over 70inches annually!). Alpine Peatlands occur in shallowbedrock depressions and on gentle slopes where theabundant moisture from precipitation and fog is capturedor retained. Peat accumulation is generally less than twofeet in basins and may be as little as six inches on gentleslopes. This shallow peat accumulation may be the resultof dry summer conditions when the peat becomes oxidizedand decomposition may be more rapid. Fully saturated peatis heavy and may slump and slide short distances alongthe gentle slopes. When this occurs near cliff edges, smalllumps of peat may break off and fall. This community isfound in association with both Alpine Meadow andSubalpine Krummholz.
Alpine Peatlands have much in common with DwarfShrub Bogs and Poor Fens that occur at lower elevationsand could be considered variants of these types. They aredescribed separately here because of the unique environ-mental setting and the presence of several characteristicplant species. The portions of Alpine Peatlands thatresemble Dwarf Shrub Bogs have raised peat surfaces andreceive all of their water and nutrients from precipitation(ombrotrophic). Wetter areas resemble Poor Fens andapparently receive some mineral enrichment from runoffand from contact with the underlying acidic bedrock.
ALPINE PEATLAND
DISTRIBUTION/ABUNDANCEAlpine Peatlands are
known only from the highestpeaks of the Green Mountainsin Vermont. This community isknown from alpine regions ofthe Adirondacks of New Yorkand the White Mountains ofNew Hampshire and Maine.Similar communities are morecommon to the north inCanada.
Profile / 325
VEGETATIONThe raised, boggy portions of Alpine
Peatlands are dominated by low-growingheath shrubs, primarily alpine bilberry,leatherleaf, Labrador tea, and blackcrowberry. The bright red Sphagnumcapillifolium forms a nearly continuouscover under the shrubs with lichenscommon in some areas. Hare’s tailcottongrass, the rare Bigelow’s sedge,and small cranberry may also be abundant.There are scattered, stunted balsam firtrees that are less than three feet tall.
The wetter, fen-like portions of AlpinePeatlands area mixture ofsmall poolsand Sphag-num-dominated“lawns.”Floating in theshallow poolsare scatteredplants ofSphagnumcuspidatum, aweak-stemmedyellowishspecies thatbecomesstranded asthe pools dry out in the summer. Thegreenish-black liverwort Gymnocoleainflata forms dense patches at the edgesof the pools and in the lowest portions ofthe lawns. The moist lawns are carpetedby Sphagnum fallax and Sphagnummagellanicum with a dense cover of poorsedge and hoary sedge. The rare deer-hairsedge grows in the sloping portions of thepeatlands near the cliff edges.
ANIMALSLittle is known about animals that use
Alpine Peatlands specifically. See AlpineMeadow and Krummholz for a discussionof species that use these associatedcommunities.
VARIANTSNone recognized at this time.
RELATED COMMUNITIESDwarf Shrub Bog: This peatland
community occurs at elevations belowtreeline, typically has scattered black spruceand tamarack, and lacks alpine bilberry,black crowberry, and Bigelow’s sedge thatare characteristic of Alpine Peatlands.
Poor Fen: This peatland communityalso occurs below treeline and typicallyincludes stunted black spruce, tamarack,and red maple trees. Alpine Peatlands have
very shallowlayers of peatlying directlyover bedrock,whereas PoorFens typicallyhave deeppeat overmineral soils.
CONSERVATION
STATUS AND
MANAGEMENT
CONSIDERATIONSAlpine
Peatlands andother alpinecommunities
are extremely rare in Vermont. The AlpinePeatlands on Mount Mansfield are ownedand managed by the University of Vermontand are readily accessible from the toll roadthat climbs to the summit. The primarythreats to these small wetlands and othersensitive alpine communities are tramplingof vegetation by curious visitors anddevelopment of broadcasting facilities onthe ridgeline.
PLACES TO VISITMount Mansfield, Stowe, University of
Vermont Natural Area
ALPINE PEATLAND
The tiny black crowberry is abundant in our rare alpinecommunities.
Open Peatlands / 325
326 / Wetland, Woodland, Wildland
CHARACTERISTIC PLANTS
ALPINE PEATLAND
TREESOccasional to Locally Abundant SpeciesBalsam fir – Abies balsameaPaper birch – Betula papyrifera
Bliss, L., 1963. Alpine plant communitiesof the Presidential Range, New Hamp-shire. Ecology 44: 678-697.
Sperduto, D.D. and C.V. Cogbill, 1999.Alpine and subalpine vegetation of theWhite Mountains, New Hampshire.New Hampshire Natural HeritageInventory.
Profile / 327
ECOLOGY AND PHYSICAL SETTINGIn the continuum of peatland types, Poor Fens are
closely related to bogs. They are open peatlands dominatedby sphagnum mosses, sedges, and heath shrubs. Thiscommunity type is in fact transitional between Dwarf ShrubBog and Intermediate Fen and shares characteristics witheach of these types.
Poor Fens are wetter than Dwarf Shrub Bogs andtypically have water levels at or just above the surface layerof peat for much of the growing season. Poor Fen watersare acidic (pH of 3.5 to 5.5), but unlike bogs, they areslightly enriched by groundwater seepage. Because theytypically occur in areas of acidic to weakly calcareousbedrock, the groundwater seepage delivers a low concentra-tion of dissolved minerals to the fen surface. The effect ofthis slight mineral enrichment is clearly evident in thevegetation that grows in the moist hollows of Poor Fens.The tall hummocks stand one to three feet above the waterin the hollows and may be completely ombrotrophic,receiving water and nutrients entirely from precipitation.Water squeezed from sphagnum at a hummock top mayhave a pH near 3.5, whereas water in an adjacent hollowtypically has pH ranging from 5.0 to 5.5. The vegetationon these hummocks shows no signs of mineral enrichment.
Poor Fens occur in a variety of physical settings, fromsmall isolated basins to large wetland complexes that maybe associated with streams. They generally have deep peat,made up primarily of poorly decomposed sphagnum andsome sedge and woody material. They also occur as floatingpeat mats, growing out over the open water of small acidicponds such as kettle hole depressions. Poor Fens commonlyoccur with Dwarf Shrub Bogs and/or Intermediate Fens andmay grade into either of these community types.
DISTRIBUTION/ABUNDANCEPoor Fens are rare in
Vermont and are foundin areas of acidic to weaklycalcareous bedrock. PoorFens are found from thenorthern Lake States toNew England and northinto Canada.
POOR FEN
Open Peatlands / 327
328 / Wetland, Woodland, Wildland
VEGETATIONThe well-developed hummocks of most
Poor Fens are very similar to those foundin Dwarf Shrub Bogs. There is a completecover of sphagnum, with the typicalzonation from hummock top to bottombeing Sphagnum fuscum, Sphagnumcapillifolium, Sphagnum magellanicum,Sphagnum angustifolium, and Sphagnumfallax. A sparsecover of heathshrubs are presenton the hummocks,with leatherleaf andbog rosemaryespecially common,and lesser amountsof bog laurel,Labrador tea, andsheep laurel.Stunted blackspruce, tamarack,and red maple arescattered across thewidely spacedhummocks. Smallcranberry, is a low, creeping, woody plant,as well as the herbaceous three-seededsedge, few-flowered sedge, hare’s tailcottongrass, pitcher plant, and round-leaved sundew are also common on thehummocks.
The hollows in Poor Fens are larger andwetter than in Dwarf Shrub Bogs andtypically contain standing water for muchof the growing season. Sedges are commonin these wet hollows, especially mud sedge,white beakrush, and hairy-fruited sedge.Other species found in the hollows that areindicators of slight mineral enrichmentinclude bog-bean, Virginia cottongrass, andspatulate-leaved sundew. There are com-monly wide moist “lawns” just above thewater table that are dominated by the brownSphagnum papillosum, a species that is verycharacteristic of Poor Fens. Sphagnumpulchrum is another, less common Poor Fenspecies that also forms moist lawns. Mudsedge and white beakrush may be commonin these lawns, as may bog rosemary and
small cranberry. Other bryophytes that arefrequently present include Sphagnumflexuosum and the liverwort Cladipodiellafluitans, which occasionally forms dark matsacross moist hollows that are referred to asmud-bottoms.
ANIMALSSome breeding birds of Poor Fens
include Lincoln’s sparrow, commonyellowthroat,white-throatedsparrow, swampsparrow, andcommon snipe.This watery, mossyhabitat may beused by southernbog lemmings,meadow voles,and maskedshrews. The rarefour-toed sala-mander andspotted turtle mayboth be found in
Poor Fens that have an associated pool,especially in the warmer regions of the state.Pickerel frogs and red-bellied snakes mayalso be present. Dragonflies and damselfliescan be abundant in Poor Fens.
VARIANTSNone recognized at this time.
RELATED COMMUNITIESDwarf Shrub Bog: This open peatland
community is dominated by sphagnum andheath shrubs and is ombrotrophic, receivingmost of its water and nutrients fromprecipitation. Dwarf Shrub Bogs generallylack the species found in Poor Fens thatindicate mineral enrichment.
Intermediate Fen: This open,mineral-enriched peatland is dominatedby hairy-fruited sedge and sweet gale, withabundant brown mosses. Sphagnum andheath shrubs are uncommon, except onhummocks.
POOR FEN
A colorful combination of sphagnum moss andbog rosemary.
Profile / 329
CHARACTERISTIC PLANTS
POOR FEN
CONSERVATION STATUS AND
MANAGEMENT CONSIDERATIONSPoor Fens are rare in Vermont, and most
of our examples are small compared tothose occurring in Maine and to the northin Canada. As with other wetland commu-nities that are fed by groundwater, PoorFens are threatened by land use changesthat occur within both their immediatewatersheds and within their groundwaterrecharge zones. Protecting the quality andquantity of groundwater that dischargesinto a fen is critical to maintaining thehydrology and the vegetation structure andcomposition of the community. However,identifying the location of the groundwaterrecharge zone of a particular fen requiresdetailed hydrogeologic study and can
greatly complicate planning and protectionefforts.
PLACES TO VISITFifield Pond Bog, White Rocks National
Recreation Area, Wallingford, GreenMountain National Forest ManchesterRanger District
Morrill Brook Fen, Steam Mill BrookWildlife Management Area, Walden,Vermont Department of Fish andWildlife
SELECTED REFERENCES AND FURTHER
READINGCrum, H. 1988. A Focus on Peatlands and
Peat Mosses. University of MichiganPress, Ann Arbor.
CHARACTERISTIC PLANTS
TREES (STUNTED)Occasional to Locally Abundant SpeciesBlack spruce – Picea marianaTamarack – Larix laricinaRed maple – Acer rubrum
ECOLOGY AND PHYSICAL SETTINGIntermediate Fens are open peatlands dominated by tall
sedges, non-sphagnum mosses, and a sparse to moderatecover of shrubs. This community is fed by ground or surfacewater that is moderately enriched with dissolved mineralsand has a pH ranging from 5.4 to 7.4. In this regard, thiscommunity type is intermediate between Rich Fens andPoor Fens, with which it often occurs. Intermediate Fensare wet and commonly have water at or slightly above thesurface of the peat for most of the growing season.
Intermediate Fens are commonly found in former lake orpond basins that have been filled by peat deposits. In someexamples, a central pond remains and there is a floatingpeat mat held together by sedge and shrub roots that extendover the alkaline lake or pond water. Fens with floatingmats of this type may also be found extending over the veryslowly moving water of rivers and streams flowing throughpeatland complexes. These pioneering mats may bepartially supported by flocculent deposits of peat andcolloidal lake sediments, all of which give a false impressionof structural integrity to the curious but unwary naturalistwho may take an ill-fated step onto the mat.
Intermediate Fens typically have deep peat deposits thatrange from three feet to over 13 feet. The poorly decom-posed peat is generally sedgy, with some moss and woodfragments present. In deeper basins, it is common to findlake sediments underlying the peat, including gyttja, agreenish, gelatinous, organic sediment made up of plank-tonic algal remains and the feces of lake bottom fauna.
DISTRIBUTION/ABUNDANCEIntermediate Fens in
Vermont are restricted toareas with calcium-richbedrock. Similar communitiesare found throughout NewEngland, the Lake States,and north into Canada, alsoin areas of calcium-richbedrock.
INTERMEDIATE FEN
Profile / 331
VEGETATIONAlthough there may be occasional tall
hummocks in Intermediate Fens thatprovide habitat for species typical of bogs,the majority of these fens are open andrelatively flat. Some have low hummocksand wet hollows. Hairy-fruited sedge is thedominant herbaceous plant, and this tall,gracefully bending sedge may be all that isvisible when looking across an expanse offen. However, there are usually many othershorter herbaceous plants present as well.Other characteristic herbs include watersedge, twig rush, and bog-bean. Shrubbycinquefoil is a characteristic shrub and maybe abundant in some fens, as may sweetgale. Other vascular plants that vary in theirabundance are Hudson Bay bulrush, whitebeakrush, bog goldenrod, single-spikemuhlenbergia, mud sedge, marsh cinque-foil, and the shrubs alder-leaved buckthorn,small cranberry, hoary willow, and bogrosemary.
The bryophytes of Intermediate Fens arehighly characteristic and may form nearly100 percent cover under the sedge layer insome areas. Starry campylium is typicallythe dominant moss and is a good indicatorspecies for Intermediate and Rich Fens.Other characteristic mosses includeCalliergonella cuspidata, Tomenthypnumnitens, and Sphagnum warnstorfii. Therare mosses Paludella squarrosa andScorpidium scorpioides are also characteris-tic of mineral-rich fens. In portions ofIntermediate Fen areas that are pioneeringmats over alkaline ponds or slowly movingstreams, Sphagnum teres, Sphagnumsubsecundum, and Calliergon stramineummay all be common. The thallose liverwortMoerckia hibernica is a distinct calciphile(a calcium-loving plant) and is commonlyfound in mineral-rich fens.
ANIMALSSome breeding birds of Intermediate
Fens include Lincoln’s sparrow, commonyellowthroat, swamp sparrow, and com-mon snipe. This habitat may also be usedby meadow voles and masked shrews.Several species of dragonflies are character-istic of Intermediate and Rich Fens.
Common species include Canada darner,lake darner, and variable darner. Rarespecies include black-tipped darner, green-tipped darner, and elfin skimmer.
VARIANTSNone recognized at this time.
RELATED COMMUNITIESRich Fen: This fen type is strongly
influenced by mineral-rich groundwaterand is dominated by low sedges and non-sphagnum mosses. Rich Fens are typicallygently sloping and occur on shallow peat.
Poor Fen: This peatland type receivesgroundwater that is slightly enriched withminerals. Poor fens are dominated bysphagnum mosses, sedges, and heathshrubs, with well-developed hummocksand hollows.
CONSERVATION STATUS AND
MANAGEMENT CONSIDERATIONSIntermediate Fen is a rare community
type in Vermont, with all known examplesunder 50 acres and most examples onlyseveral acres. Fens that develop and aremaintained under the influence of mineral-rich groundwater seepage or discharge arethreatened by alterations in the quality orquantity of the associated groundwater.Identification of groundwater rechargeareas requires detailed geologic andhydrologic study of the surroundinglandscape but is necessary to ensure long-term protection of these communities.Examples of Intermediate Fens that occuralong shorelines of ponds or slowly movingstreams are threatened by alteration ofwater levels or natural hydrologic regimes.The vegetation in fens is extremelysusceptible to trampling and, therefore,visits should be limited to sites withboardwalks or to the uplands adjacent tofens. Although there are some high qualityexamples of this community type on publicor private conservation land, additionalprotection is needed. Vermont has some ofthe best examples of this community typein the Northeast.
PLACES TO VISITChickering Bog Natural Area, Calais,
The Nature Conservancy
SELECTED REFERENCES AND FURTHER
READINGThompson, E. and R. Popp. 1995. Calcare-
ous open fens and riverside seeps ofVermont: some sites of ecologicalimportance. Vermont Nongame andNatural Heritage Program.
Crum, H. 1988. A Focus on Peatlands andPeat Mosses. University of MichiganPress, Ann Arbor.
INTERMEDIATE FEN
Shrubby cinquefoil – Potentilla fruticosa
Profile / 333
ECOLOGY AND PHYSICAL SETTINGRich Fens are hotspots of botanical diversity. The high
species richness of these fens results from the naturallyopen condition and the constant seepage of calcareousgroundwater.
Rich Fens typically occur on a gentle slope and haveshallow peat accumulations of less than three feet, althoughin some cases the peat is considerably deeper. Peat tends tobe more decomposed than in Intermediate Fens, but sedgeand moss fragments are still recognizable. The peat issaturated throughout the growing season, and there may besmall, shallow pools scattered over the generally concavesurface of the fen. Areas of groundwater seepage are usuallyevident at the upslope margins of Rich Fens where theremay be small pools or springs adjacent to the sharptransition to upland forest. This seepage water moves slowlyacross the fen through the upper layers of peat. It is rich incalcium and has pH ranging from 5.8 to 7.4. Rich Fensoccur only in areas of calcium or carbonate-rich bedrock.
Rich Fens may occur in isolation from other wetlandsor as part of larger wetland complexes. Rich Fens arecommonly found in small topographic depressions, withvery small watersheds, and typically form the headwatersof perennial streams. When occurring in association withSedge Meadows, calcareous Alder Shrub Swamps, marshes,Northern White Cedar Swamps, or Intermediate Fens, RichFens generally occur on the upslope edge of the wetlandcomplex where the influence of groundwater seepage isstrongest. All examples of Rich Fens in Vermont are small,with all documented examples six acres or less.
Beavers are the primary source of natural disturbancein Rich Fens. Given the proper topographic setting at theoutlet stream, a beaver can construct a dam that willimpound water over an entire fen or a portion of the fen.
DISTRIBUTION/ABUNDANCERich Fens in Vermont
are restricted to areas withcalcium-rich bedrock. Similarcommunities are foundthroughout northern NewEngland, the Lake States,and north into Canada.
RICH FEN
Open Peatlands / 333
334 / Wetland, Woodland, Wildland
The long-term effect of this type ofdisturbance and subsequent dam breachingon fen vegetation needs further study.
VEGETATIONRich Fens are dominated by “brown”
mosses (non-sphagnum mosses) and lowsedges and grasses. Low shrub cover variesfrom sparse or absent in some fens tooccasionally densein other fens.Although lesscommon than inIntermediate andPoor Fens, RichFens may also havescattered low tomoderate hum-mocks with speciescharacteristic ofbogs.
The bryophytecomponent of RichFens is welldeveloped, withmoss cover generally close to 100 percent.Characteristic mosses are starry campylium,Limprichtia revolvens var. intermedius,Calliergonella cuspidata, Philinotis fontana,Bryum pseudotriquetrum, andTomenthypnum nitens.
The low, herbaceous cover is primarilysedges, with inland sedge, porcupinesedge, yellow sedge, and delicate-stemmedsedge present in most fens. Other charac-teristic herbs include Hudson Bay bulrush,water avens, green-keeled cottongrass,Kalm’s lobelia, golden ragwort, and blueflag. Many other herbaceous plants may bepresent. Red-osier dogwood is a shrub thatoccurs in most Rich Fens but is seldom veryabundant. Shrubby cinquefoil and alder-leaved buckthorn are scattered across manyfens and are abundant in patches in others.
ANIMALSSome breeding birds of Rich Fens
include Lincoln’s sparrow, commonyellowthroat, swamp sparrow, and com-mon snipe. This habitat may be used bymeadow voles and masked shrews. Severalspecies of dragonflies are characteristic of
Intermediate and Rich Fens, includingblack-tipped darner, green-tipped darner,and elfin skimmer.
VARIANTSNone recognized at this time.
RELATED COMMUNITIESPoor Fen: This peatland type receives
IntermediateFen: This open,mineral-enrichedpeatland is domi-nated by hairy-fruitedsedge and sweetgale, with abundant
brown mosses. Sphagnum and heathshrubs are uncommon, except on hum-mocks. Peat depths are generally greaterthan in Rich Fens.
CONSERVATION STATUS AND
MANAGEMENT CONSIDERATIONSRich Fens are considered a rare commu-
nity type, both at the state and global level.Some of the highest quality examples ofthis community occur in Vermont, due inpart to the extensive areas of calcareousbedrock in the state. Many of Vermont’sRich Fens have been altered in the past bygrazing or hay-cropping, or are locatedadjacent to active agricultural fields wherethey may receive nutrient-rich runoff.Surface water runoff that is high in nitrogenor phosphorus can have a significant effecton the species composition of fens,generally leading to a decline in speciesrichness and increased abundance ofgeneralist species such as common cattail.As with other fen types and wetlands thatreceive mineral-enriched groundwaterseepage, Rich Fens are susceptible tochanges in the quality or quantity of thisgroundwater input. Protection of fen
The exquisite flowers of showy ladyslippers in afen in June.
RICH FEN
Profile / 335
communities typically requires protectionof not just the small surface watershed, butalso the area of groundwater recharge tothe fen. The vegetation in fens is extremelysusceptible to trampling and, therefore,visits should be limited to a few select siteswith boardwalks or to the uplands adjacentto fens. There are several Rich Fens that areprotected on public or conservation land.
Although beavers are a form of naturaldisturbance in Rich Fens, their effects maybe significantly increased by the presenceof human structures in the vicinity. Roadsor raised trails that cross the outlet streamsof fens are prime sites for beavers toconstruct dams. These structures should beremoved, if possible, or monitored closelyfor beaver activity. Given the rarity of thiscommunity it may be necessary to managebeaver activity even for fens in relativelypristine landscape settings.
RICH FEN
PLACES TO VISITEshqua Bog, Hartland Natural Area,
The New England Wildflower Societyand The Nature Conservancy
Chickering Bog, Calais Natural Area,The Nature Conservancy
SELECTED REFERENCES AND
FURTHER READINGThompson, E. and R. Popp. 1995. Calcare-
ous open fens and riverside seeps ofVermont: some sites of ecologicalimportance. Vermont Nongame andNatural Heritage Program.
Crum, H. 1988. A Focus on Peatlands andPeat Mosses. University of MichiganPress, Ann Arbor.
