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Allegheny wetlands fall into two groups: major complexes composed of a
variety of ecological types and minor, much simpler ones, with few types
represented. Characteristic of the first group are the so-called "Cranesville
Swamp," the Canaan Valley and the Cranberry Glades. Examples of the second
group, among many others, are Big Run Bog, Blister Swamp, Blister Run Swamp and
Red Creek Bog.
Wetland ecological types are as follows:
The first five types are usually referred to as "glades" because they contain
few trees. Swamps by definition are forests or shrublands with mostly
saturated soils or standing water. Mixtures and gradations of some types are
common and major complexes may contain all of these types. By contrast some
smaller wetlands may consist of only one ecological type.
These different ecological types are a consequence of climatic factors and the
geologic setting which in turn govern the chemical and biologic character of
soils and water. Thus moving ground water may, as in the Canaan Valley,
encounter limestone or other carbonates which may add calcium, magnesium and
other elements and act to counter prevailing acid conditions resulting from
silica-rich rocks, precipitation and vegetation in acid bogs. Acid bogs are
however generally isolated from such groundwater either by underlying
impermeable layers or by inputs of acid runoff from uplands with heath,
spruce-fir or hemlock-hardwood forest. In more elevated areas within wetlands
acid leaching may be operative and result in podzolic soils. These locations
may have isolated acid-soil upland communities -- Canada Mayflower, Partridge
Berry -- under hemlock, spruce or fir while the surrounding open wetland is
less acid in character and consists of shrub swamp, meadow or marsh.
While a cool, humid climate results in podzolic soils as a result of downward
leaching of bases, the reverse may occur in dryer areas during dry spells when
these same bases are brought nearer to the surface by capillary action. An
extreme case of this is the formation of caliche surface crusts in deserts.
However the upward transport of bases is prevented by a high water table fed by
acid runoff even on uplands, which may then develop acid-soil communities
containing sphagnum, cranberries and other hydric species and even peat
deposits similar to those of bogs. Indeed a number of Allegheny bogs are
developed on significant slopes.
Heaths generally are upland areas which have been deforested, severely burned
or otherwise abused by humans. The loss of deep organic topsoils associated
with spruce-fir forests through erosion, drying or burning after deforestation
sets the stage for heath formation. Because trees cannot grow back in the
stony residue, the water table rises and both capillary action and upward
transport of nutrients by tree roots almost ceases. Acidification is then
accelerated by the accumulation of sphagnum and associated acid-producing
organic matter. This process is so effective that acid heaths and peat
deposits may be produced even above underlying limestone or marl. Classic
areas occur in England where widespread heath has resulted from land abuse
dating to prehistoric times (Tubbs, 1968). Among many examples in the Central
Appalachians is Dolly Sods, a heath complex that resulted from logging and
subsequent fires. Our objective here is to gain a coherent picture of various
wetlands and heaths in terms of their observed biologic communities.
Tubbs
In terms of geological structure the area falls in a breached anticline with a
core of Mississippian Pocono formation and a rimming Greenbrier Limestone (West
Virginia Geologic and Economic Survey, 1968). Much of the complex lies above
the limestone and so poses a challenge of interpreting the diverse ecological
types in terms of ground and surface water movement. In general the west side
of the complex appears to be the most acid while the east side is more under
the influence of the limestone.
Records indicate that before it was degraded by logging and other destructive
land uses, this wetland was nearer to a true swamp than at present, with
extensive stands of Spruce, Hemlock, White Pine and Eastern Larch (Larix
laricina). It is likely that both the decrease in area and amount of
forest are a consequence of general deforestation not only of the wetland but
also of the surrounding watershed. This degradation is still showing its
effects, although in some respects the recovery is occurring under more
enlightened management. The centerpiece species here is Eastern Larch because,
as far as is known, Cranesville is the southernmost station on Earth for this
species. Another case in point is the boreal herb Buckbean, which was first
discovered here in 1905 (Strausbaugh and Core, 1977), but has apparently died
out since then. The same appears to have happened to Harneds Clintonia
(Clintonia allegheniensis), a Central Appalachian endemic once found
here.
The original forest of the bordering upland was probably Hemlock-White
Pine-northern hardwood with an admixture of Red Spruce. Today this forest is
still badly degraded and consists in part of alien Norway Spruce and Red Pine
plantations. However there are also recovering stands of Black Cherry, White
Pine, Hemlock, Red Maple, Black Locust and other hardwoods. Characteristically
of the Alleghenies, Black Cherry does particularly well, growing straight, tall
and of good form. It is clear that this enveloping forest is important to the
continuing stability of the system and its recovery and expansion would be of
great benefit and could even result in the return of extirpated species.
East and northeast of the Nature Conservancy parking lot there is an open
sedge/grass/forb meadow with scattered and rimming shrubs and trees. In some
places there are small meandering, steep-banked streams or old Beaver floodings
with dead trees. In a few places upwellings of water probably mark artesian
springs. Where shrubs are more abundant the land may be classified as shrub
swamp. Trees scattered throughout this swamp and the meadow are Red Spruce,
Hemlock, White and Pitch Pines, Red Maple, and in dryer areas, Black Cherry.
Smaller trees, particularly in dryer areas, include Hawthorns, Wild Crabapple
(Malus coronaria), Mountain Ash (in bloom at this season) and Service
Berry (Amelanchier lævis?). Also one Choke Cherry (Prunus
virginiana) was seen. In wet areas the most common shrub is Speckled Alder
(Alnus rugosa), followed by Wild Raisin, Black Chokeberry (also in
bloom), Arrowwood (Viburnum dentatum) and Glade St. Johnswort
(Hypericum densiflorum). There are also scattered Black Elderberry,
Winterberry Holly and Nemopanthus mucronata , a member of the Holly
family that reaches its southern limit in high elevation Allegheny glades. Two
unidentified species of Dogwood were also seen. There are also Mtn. Laurel,
Great Rhododendron and Witch Hazel and on this visit the Mountain Laurel had
just begun to bloom --much later than in the mountains to the south. As in
most Allegheny wetlands, blueberries are common. The most abundant is Sourtop
(Vaccinium myrtilloides) but Early Low Blueberry (V.
angustifolium) is also common. In dryer areas Deerberry (V.
stamineum) flourishes as large vigorous plants and at this season is
covered with its white, open blossoms. Although cranberries are most
characteristic of open sphagnum bogs, it is not unusual to come upon small
patches of them (either V. macrocarpon or V. oxyccos) in brushy
sedge openings in which they are invariably associated with local
Sphagnum however. Other small heaths, again in dryer areas, are
Teaberry and Trailing Arbutus.
In many places, as in the surrounding forest, ground cover is dominated by
Rubus hispidus , or in dryer areas by Potentilla canadensis
/simplex or Wild Strawberry. Narrow-leaf Gentian (Gentiana
linearis) is, as is usual in Allegheny wetlands, almost omnipresent, though
seldom abundant, in wet areas, as is Arrowleaf Tearthumb (Polygonum
sagittatum), which sprawls across low vegetation with its flesh-cutting
vines. Where forbs are favored in the meadow, composites tend to dominate and
if the soil is not too wet, Wrinkled-leaf Goldenrod is the most abundant plant.
However in wet areas this is likely to be replaced by Bog Goldenrod
(Solidago uliginosa), which more frequently than not occurs only as leaf
rosettes.
At least six fern species, some adapted to a range of habitats, others more
restricted, were seen. Most conspicuous was the large Cinnamon Fern, at this
season in full "fruit." However Interrupted, Bracken, Hay-scented and
Sensitive Ferns were also abundant and while present, New York Fern seemed less
common. Rarer by far than any other was Crested Shield Fern (Dropteris
cristata) but growing as stated by Strausbaugh and Core "in the dense shade
of alder fringes." In places large patches of Lycopodium clavatum,
L. obscurum or L. flabelliforme were noted, being differentiated
no doubt by subtle changes from one plot to another in soil moisture or
chemistry.
Of all the wetland plants the sedges seem to flourish in greatest abundance
and variety. Most striking are the large Carex such as C.
crinita, C. lurida and C. rostrata, but those of lesser
stature like C. stricta, C. scoporia, C. baileyi, C.
intumescens, C. stipata, C. canescens and C. interior
are also conspicuous. Of these C. interior and C. canescens
are northern in their distribution and near their southern limits in the
Central Appalachians. However C. interior is very abundant at
Cranesville and, although small, its clumped form stands out. As we shall see,
this list is far from exhausting this genus here.
Other aquatic and wet soil plants encountered in the general area of meadow
and swamp include the Rush Juncus effusus, a Spikerush
(Eleocharis sp.), Burreed (Sparganum sp.), the carnivorous
Round-leaved Sundew (Drosera rotundifolia) (Invariably with
Sphagnum), Jewel
In dryer areas native grasses include Poverty Oatgrass (Danthonia
spicata) and Panicum dichotomum and where most disturbed by humans,
the alien Rough Bluegrass (Poa trivialis) and Velvet Grass (Holcus
lanatus).
One of the few alien species that seems able to compete with native plants of
the wet meadow is Field Sorrel (Rumex acetosella) which in this
environment seems to "fit in."
While fungi were not conspicuous, at this season one species of gill mushroom,
Tricholomopsis platyphylla was rather common.
Although most of the Cranesville wetland complex consists of forest, shrub
swamp and wet meadow, there are substantial areas of true quaking bog or
muskeg. Access to this bog is by boardwalk. Ground cover in the bog consists
largely of Sphagnum mosses, Cranberry (Vaccinium macrocarpon
and V. oxycoccos). Sourtop Blueberry, Rubus hispidus and
various other low herbs and shrubs. Scattered trees are largely Red Spruce,
Eastern Larch, White and Pitch Pines, Hemlock and Red Maple, while tall shrubs
include Wild Raisin, Arrow-wood Viburnum, Black Chokeberry, Glade St. Johnswort
and Nemopanthus mucronata. In some places taller herbs such as Cinnamon
Fern, Carex folliculata and Skunk Cabbage spread above the shorter
plants and seem to dominate. There are also some cattails (Typha
latifolia), which however, are stunted and yellowed and do not seem to
thrive in this acid environment. Although represented by such species as Rice
Cutgrass (Leersia oryzoides), grasses scarcely compete with sedges. In
harmony with the generally nutrient-poor environment is the presence of
Round-leaved Sundew and Bladderwort (Utricularis cornuta), both of which
obtain nutrients from animals they capture. Despite this somewhat inhospitable
habitat Gray Catbirds and Chickadees were seen and the song of the Swamp
Sparrow (Melopiza georgiana) was heard.
On the rainy morning of 6-12-95 a rapid foray was made to the west side of the
southern tract of the Cranesville wetland. The wetland at the site inspected
is largely a forb meadow with bordering shrubs and is one of the few stations
in the Central Appalachians of Jacobs Ladder (Polymonium
van-bruntiæ). This species flourishes over about an acre as observed
and, of the hundreds of plants here, many were in bloom with conspicuous but
delicate light purple blossoms. A partial list of associated species includes
Wrinkled-leaf Goldenrod, Skunk Cabbage, Cattail (Typha latifolia),
Cinnamon Fern, Purple Angelica (Angelica atropurpurea) and Black
Elderberry. The impression is one of less acid soils than those encountered in
the northern tract, but is based on too limited observations to be
conclussive.
The richness and diversity of the Cranesville flora are matched by those of
the fauna, which range from Black Bear and Snowshoe Hare to Northern
Water-Shrew (Venable). In June birdlife and insects impinge most regularly on
ones consciousness. Among birds, the calls of Veeries were most frequently
heard and Scarlet Tanagers flashed their brilliance even far out in the shrub
swamp where they were accompanied by the occasional Common Yellow Throat
(Geothlypis trichas), other unidentified Warblers, Mallard Ducks, Gray
Catbirds, Swamp Sparrows and the calls of Green Frogs (Rana clamitans).
In places Beaver sign in the form of recently flooded and chewed Alder and
trees set the stage for future diversity. And there were also surprises, such
as abundant Crayfish castings in areas acid enough to contain Sphagnum,
perhaps indicating that the acidity was a shallow soil phenomenon. But this
brief survey could not do justice to such a rich ecosystem as was confirmed by
Dr. Robert Hunsucker in subsequent July visits during which he recorded
fade-glimpses of Otter (Lutra canadensis), the rare Bog Copper Butterfly
(Lycæna epixcanthe) which feeds on cranberries, as well as
abundant Mourning Cloak Butterfly (Nymphalis antropa) larvæ on
Silky Willow (Salix sericea). During that visit Dr. Hunsucker also
considerably expanded the observed flora as follows: Orchids: Habenaria
orbiculata (a normally high elevation/northerner), H. clavellata and
H. lacera;; the grasses Glyceria melicaria, G. canadensis
and G. laxa (the last two near their southern limits); the sedges:
Carex atlantica, C. comosa, C. gynandra, C.
normalis, C. gracillima, Scirpus cyperinus, White Beakrush
(Rhynchospora alba) and Cottonsedge (Eriophorum virginicum); the
rushes:Juncus acuminatus and J. articulatus (the latter near its
southern limit) and the ferns: Marsh Fern (Thelypteris palustris) Bog
Fern (T simulata) and the Mountain Wood Fern (Dryopteris
campyloptera), also north-ranging species, and in the case of the last two
named, rather uncommon.
A yet more extensive list of species not observed in this survey may be found
in the literature referred to earlier. If we confine ourselves solely to
northern species ranging south along the Appalachians, the following stand out:
Common Snipe (Capella gallinago), Brown Creeper (Certhia
familiaris), Hermit Thrush, White Hellebore, Yellow Clintonia, Painted
Trillium, White Wood Sorrel, Bunchberry (Cornus canadensis), Creeping
Snowberry and Nannyberry (Viburnum lentago). There are also curious
absences, at least in our survey. These include the generally abundant Striped
Maple and Minnie-bush (Menziesia pilosa) so common in the mountains and
in Allegheny wetlands elsewhere.
The forest diversity and character here are best shown by the ground cover and
vines. The former is dominated by Rubus hispidus , but Canada Mayflower
is also extraordinarily abundant. Other broad-leaved herbs are White Clintonia
(Clintonia umbellulata), Spring Bluets (Houstonia cerulea) and
White Violet (Viola blanda and or V. pallens), all in bloom;
also Indian Cucumber-root, Four-leaved Yam, Potentilla
simplex/candensis, Panicled, Big-leaf and Mountain Asters,
Northern Swamp Buttercup, Basil Balm (Monarda clinopodia), Canada Lily,
Wrinkled-leaf and Wreath Goldenrods, Upright Yellow Wood Sorrel and Cowbane
(Oxypolis rigidior). Hay-scented Fern is very abundant, while New York,
Spinulose Shield and Interrupted Ferns are less common. Lycopods are
represented by Lycopodium flabelliforme, L. clavatum and L.
lucidulum; and grasses by Brachyelytrum erectum, Deertongue, Fowl
Mana and White Grasses. Two Woodrushes, Luzula echinata and L.
acuminata, were also noted. The only vines encountered were Common
Greenbriar and Carrion Flower. In addition a few plants of Teaberry and
Trailing Arbutus were observed on the road bank.
It is likely that the sampling of the diversity of this forest during this
short visit is very incomplete. However the observed species composition and
both woody plant and herb density indicates a rich acid-mesic environment
despite the forests immaturity and secondary character. This richness is also
supported by the apparent site quality for Black Cherry which, as elsewhere on
the Allegheny plateau, grows straight and tall with a good form. Similarly, a
strong northern component is shown by such species as Canada Mayflower.
Mountain Aster and Sourtop Blueberry.
[1]Some of these statistics were gleaned from
the excellent populariztion entitled Cranesville Swamp by N.J. Venable
of the West Virginia Extension Service. Also the plant ecology has been
extensively studied by Robinette (1964).
Wetlands of the Alleghenies
Glades, Swamps and Heaths of the Alleghenies
The Allegheny Mountain and Plateau Province is blessed with a great diversity
of wetlands. Many of these wetlands remind one of the northern US and Canada;
however in the north most wetlands stem from an entirely different source,
namely glacially-disrupted drainage. In the Alleghenies wetlands generally
appear to result from a combination of prevailing flat-lying or low-dip rock
strata ( Cardwell et al ,1968 ), the fortuitous location of resistant
beds downstream from less resistant ones and relatively high yearly
precipitation and cloud cover.
References
Cardwell, Dudley H., Robert B. Erwin, Herbert P. Woodward and
Charles W. Lotz compilers, (1968), Geologic Map of West Virginia,
Slightly Revised 1986, West Virginia Geologic and Economic Survey.
Cranesville "Swamp" Complex
General This famous wetland complex lies within the Allegheny Mountains on the
Maryland-West Virginia line at 39deg.31' North and at a mean elevation of
2560 ft (780 meters) asl. Precipitation is of the order of 50 inches (130
cm) a year with some falling as 150 inches (380 cm) of snow.[1] In the 1870s the wetland covered more than 1600 acres
(650 hectares) but it has now fallen in area to less than 800 acres (320
hectares). It is divided into north and south tracts of which 300 acres
(120 hectares)
belong to The Nature Conservancy.
Northern Wetland Section with a Little of the Southern Section
Source Walks: 6-11-95 and 6-12-95
Traverses were made in the vicinity and toward the east and northeast of the
Nature Conservancy parking lot. The general area is dominated by
sedge/grass/forb meadows with scattered and bordering shrubs and trees. Upland
forest lies to the northwest and the main wetland to the east. The bordering
forest canopy is as described earlier and with hawthorn and serviceberry
(species undetermined) in the understory. Ground cover is dominated by
Rubus hispidus, Lycopodium flabelliforme, L. obscurum,
Canada Mayflower, Partridge Berry, Spinulose Shield Fern, Indian Cucumber-root,
Skunk Cabbage and Gay Wings, with Rubus hispidus, the Lycopods and
Canada Mayflower the most abundant. There are also Hay-scented Fern,
Four-leaved Yam and Black Chokeberry, the latter mostly as seedlings. In some
places the Arctic herb Goldthread (Coptis groenlandica) forms dense
patches on east-facing slopes under trees where the upland begins. A spot
inventory of a Goldthread community yielded the following: canopy of Black
Cherry, Red Maple, Northern Red Oak and Adelgid-free Hemlock, an understory of
Service Berry (Amelanchier lævis?) and Black Chokeberry and ground
cover of Cinnamon Fern, Rubus hispidus, Indian Cucumber-root, Canada Mayflower
and Carex gracilescens. There is also a little Vaccinium
angustifolium. The Goldthread is closely intergrown with Rubus
hispidus and Red Maple and Black Chokeberry seedlings. It occurs on
elevated soil and on protruding tree roots.
Garrett State Forest Campgroundweed, Marsh Purslane (Ludwigia
palustris), a Fireweed (Epilobium sp.), marsh St.
Johnswort (Hypericum virginicum). False Pimpernel (Lindernia
dubia), Mad-dog Skulcap (Scutellaria lateriflora),
Bugleweed (Lycopus sp.) and in the streams, Water
Starwort (Callitriche heterophylla). Mosses other than Sphagnum
are also common, with the Haircap Polytrichum commune forming large
mats locally. Grasses identified are Deertongue (Panicum clandestinum),
Fowl Mana (Glyceria striata) and in some places the tall blue-green Blue
Joint (Calamagrostis canadensis), which was so characteristic of
Allegheny glades before they were overgrazed by settlers.
Source Walk: 6-11-95 and 6-12-95. Rainy The evening, night and morning were spent in a tract of the Garrett
State Forest perhaps five miles (8 km) southeast of the Cranesville
wetland. The elevation here may be as much as several hundred feet (100
meters) above the wetland; however the precise location of the campground
was not determined, so the elevation too is uncertain. The opportunity,
although secondary to camping for the night, was to make a spot inventory
of the regional forest at some distance from the wetland. The forest here
is young, perhaps 30 or 40 years in age. It appears to be a blend of
Appalachian Oak and northern hardwood. Although no Hemlock were observed
in the immediate vicinity of the camp, this tree has a scattered
occurrence, mostly as understory throughout the forest observed along the
road. At the camp site canopy species in rough order of abundance are
White Oak, Black Cherry, Red Maple, Northern Red, Black and Scarlet Oaks
and Black Birch. Serviceberry and Hawthorn are common in the understory
and there is a little Sassafras as well. Shrubs include Witch Hazel, Black
Chokeberry, Wild Raisin, Upland Low and Sourtop Blueberries and Smooth
Azalea (Rhododendron arborescens),with the latter in bloom.
There are also scattered American Chestnut sprouts.
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