The following sections describe six different wetland habitats which I have visited and studied extensively in preparing this unit. While it may be difficult for a class to go out in the field to these particular sites, the teacher easily can bring plant and animal components of these habitats into the classroom. The slide set that I have put together (see Classroom Materials) can serve to introduce the students to these wetlands.
WEST ROCK RIDGE VERNAL POOL, HAMDEN, CONNECTICUT
(Topographic Maps: New Haven Quadrangle, New Haven County, Connecticut) Vernal pools are shallow wetlands which form in winter and early spring from snow melt and rainfall. Vernal pools may form in low-lying areas such as at the base of a slope or adjacent to a stream, or they may be perched on ridgetops in depressions. They typically persist until mid-summer in Connecticut, when the onset of consistently warm weather leads to their complete evaporation. Vernal pools (or spring pools) thus are ephemeral, or seasonal wetlands. Their food chain is based on the breakdown of detritus, the leaves, twigs and other organic matter which falls into the pool through the year.
West Rock Ridge in the towns of New Haven, Hamden, Woodbridge and Bethany has a number of vernal pools, most of them in the low-lying lands adjacent to the West River (west of the ridge) and beside Wintergreen Brook (east of the ridge). The vernal pool I have studied is one of a few located on top of the ridge; it is east of the paved overlook to Lake Dawson. The pool is approximately 50 meters long and 10 meters wide, and it is adjacent to the east slopes of the ridge. There is an old stone wall within a few feet of the north end of the pool, but I believe the depression to be naturally formed, perhaps from glacial scouring. Approaching the pool, the prevailing image one has is of being in a forest and simply finding a low, wet area of forest floor. The special biological characteristics of the pool only become apparent with closer examination over a period of weeks.
Because of the ephemeral nature of vernal pools, vertebrate and invertebrate organisms residing in them must complete key stages in their life cycles, particularly larval stages, during the brief time water is present. Several amphibian species are dependent on vernal pools for reproduction, including courtship, egg fertilization and deposition, larval development, and metamorphosis to the terrestrial stage. Amphibians I have found in the West Rock ridge top vernal pool are Spotted Salamander (
), one of several
salamander species found in the state, and Wood Frog (
Wood Frog is a medium-sized frog with a brown body and a dark masked appearance around the eyes. This northern boreal frog reaches its southernmost distribution in the Appalachian Mountains south to Georgia. It is a widely distributed species throughout Connecticut in dense deciduous and coniferous forest. Wood Frog prefers to breed in vernal pools, where females deposit a communal egg mass in shallow water. It is also known to breed in wet meadows, swamps, bogs and fens, and roadside ditches. Spotted Salamanders live primarily in forested areas where there are nearby vernal pools or semi-permanent ponds. On March 18 of this year I visited the West Rock Ridge vernal pool on the night of March 21, and I observed hundreds of Spotted Salamanders engaged in reproductive behavior. This date matches the second earliest published record of Spotted Salamander breeding in Connecticut. The species overwinters in underground burrows or cavities, and individuals emerge in late winter and early spring when upper layers of soil thaw, air temperatures reach 50 degrees Fahrenheit, and then only after dark when there is a warm rain or heavy fog and humidity is high. Males migrate to ancestral vernal pools, followed shortly by females, and there begins an elaborate group courtship and breeding. Males locate and rub against females, then swim to the pool’s bottom to deposit spermatophores on dead leaves. Females make contact with spermatophores and draw them into the cloacal opening for fertilization of eggs. Within 48 hours, females deposit egg masses of 50-200 eggs on submerged branches in the deeper sections of the pool. Spotted Salamander larvae eventually hatch out of the egg mass, grow in size, and metamorphose into air-breathing terrestrial tetrapods—all this before the vernal pool dries up completely. (Space constraints prevent me from giving a more detailed description of Spotted Salamander life history. I refer the reader to an upcoming issues of the West Rock Ridge Park Association Newsletter, which will carry an article I have written on this fascinating amphibian species.)
Other vertebrates using the vernal pool include Wild Turkey (
), which digs in surrounding dry leaf litter and finds acorn mast for food, and White-tailed Deer (
), which drinks from the water and beds down nearby. Birds which breed on the eastern slopes of West Rock Ridge in the vicinity of the vernal pool include Eastern Screech-Owl and Great Horned Owl, Downy, Hairy and Pileated Woodpecker, Great Crested Flycatcher, Eastern Phoebe and Eastern Wood-Pewee, Red-eyed Vireo and Yellow-throated Vireo, Black-throated Green Warbler, Ovenbird, Black-and-white Warbler, Worm-eating Warbler, Brown Thrasher, Wood Thrush, Hermit Thrush and Swainson’s Thrush, and Scarlet Tanager.
Vernal pools contain a wide range of insects and other invertebrates. These organisms have the benefit of adaptation to life in a body of water which, because of its ephemeral nature, lacks fish populations—potentially their principal predators. I have not yet undertaken a systematic study of the invertebrates of the West Rock vernal pool, but this is described below as an activity for students. Invertebrates living in vernal pools include oligochaete worms, water fleas (
), copepod crustaceans, fairy shrimp (restricted to vernal pools), ostracods (seed shrimp), isopods (
), water mites, mosquito larvae (
), dragonfly nymphs (Odonata), caddisfly larvae (
), diving beetles (
), water scavenger beetles (
), water bugs (
), chironomid midges (
), water striders (
), clam species, and snails (
The forest surrounding the vernal pool is part of the larger oakhickory forest which dominates the ridgetop and upper slopes. Chestnut, Scarlet, Pin, Northern Red, and White Oaks, and Mockernut, Pignut, Bitternut, and Shagbark Hickories, Sugar Maple, Red Maple, and Yellow-Poplar trees are the principal deciduous trees. Eastern Hemlock and Eastern White Pine are also found in a grove near the vernal pool, and Eastern Red Cedar (
) grows from rocky outcrops on the east slopes. The most common shrubs are Sweet Pepperbush (
) and Pussy Willow (
). Herbaceous plants of the region of the vernal pool include Yellow Corydalis (
), Wild Columbine (
), Canada Mayflower (
), Early Saxifrage (
), and Wild Geranium (
DURHAM MEADOWS RED MAPLE-GREEN ASH-TUSSOCK SEDGE SWAMP, DURHAM, CONNECTICUT.
(Topographic Map: Durham Quadrangle, Middlesex County, Connecticut) Swamps are wetlands in which trees are the dominant vegetation. These are forested wetlands. In Connecticut and throughout southern New England, the most common type of wetland is a red maple swamp. Fully 80% of Connecticut’s freshwater wetlands are
swamps. Red Maple, which derives its name from the plant’s red flowers, fruits, petioles and fall foliage, grows to a height of 60-90 feet and a diameter at breast height (DBH) of 2 1/2 feet. While it grows in dry upland sites, it is most abundant and most closely a monoculture species (single species stands) in swamps or along stream banks. It is widely distributed throughout the eastern United States.
Durham Meadows is an outstanding example of a Connecticut red maple swamp. It is situated in the floodplain of the Coginchaug River between Routes 17 and 147 in Durham. Route 68 bisects the meadows in an east-west direction. My field work has focused on the southern half of Durham Meadows, between Routes 17 and 68. This region of Durham Meadows is easily accessible by those who don’t mind getting shoes or pantlegs wet or muddy. The inner regions of this wetland are accessible only through considerable exertion, walking and wading through dense vegetation and over very uneven topography deep river channel, tussocks, grass mats, and windthrown trees.
There are at least three distinct plant communities in Durham Meadows. Just north of Route 17 an easy to reach red maple-tussock sedge swamp covers several acres. Penetrating further north into the meadows, one finds more dense growth of red maple and green ash on hummocks set back from the Coginchaug River. The immediate environment of the river is a wild rice grass riverine wetland. Scattered areas of cattail (Typha) are found on either side of the river. Further north, the forest closes in far more, with red maple and green ash dominating, and there is a dense growth of floating and emergent herbaceous plants.
Representative herbaceous and shrubby plants of the Durham Meadows wetland are sedges (
.), Skunk Cabbage (
), Arrow Arum (
), Cowslip (
), Yellow Iris (
), Larger Blue Flag (
), and Speckled Alder (
Human activities have affected all three vegetation zones of Durham Meadows substantially, including tree-harvesting, channel dredging, laying of coaxial cable through the meadows, and agricultural runoff which infuses heavy doses of phosphorus fertilizer into the wetland. In fact, the three zones of Durham Meadows described here arose probably due to different periods of logging of the trees. The presence of beaver has affected this wetland considerably. Beaverdammed stretches of the Coginchaug cause extensive flooding to either side of the river. This is particularly noticeable after heavy spring and summer rains, when the red maple-tussock sedge environment pools with sheet flow of water. A large beaver lodge is visible from the fishermen’s trail leading along the east side of the river. Muskrats also live in Durham Meadows, and their houses are scattered throughout the wetland. Meadow voles are present in the grass and sedge margins of this wetland, as are White-tailed Deer.
Durham Meadows is particularly interesting for its diverse populations of birds. Several rare, threatened and endangered breeding bird species live here, including American Bittern (state endangered) and Least Bittern (state threatened), Virginia Rail and Sora. These wetland species have declined in numbers over previous decades due in large part to loss of habitat—the draining of wetlands and their conversion to agricultural lands or residential and commercial tracts. Durham Meadows is, in fact, surrounded by farmiand, which has encroached on the historical boundaries of the wetland.
The 1984-85 Connecticut Breeding Bird Atlas confirmed breeding of both rails and Least Bittern at Durham Meadows. On May 21 of this year I several times heard the pumping sound of American Bittern deep in this wetland, convincing me that this species also breeds here. On May 5 I located the nest of Virginia Rail at Durham Meadows. It contained eight eggs the day of discovery, and one day later the nest held nine eggs. These eggs were incubated by both parents over the course of several weeks, when the nest was found to have been predated and the eggs destroyed—a common occurrence for these ground-nesting birds.
Other breeding birds of Durham Meadows include 6reen Heron, Wood Duck, Blue-winged Teal (Breeding Bird Atlas—one of only three confirmations of breeding in Connecticut), Red-shouldered Hawk (a wetland-nesting hawk), Eastern Screech-Owl, Belted Kingfisher, Willow Flycatcher, Least Flycatcher, Eastern Kingbird, Tree Swallow, Barn Swallow, Marsh Wren, Eastern Bluebird, Cedar Waxwing, Warbling Vireo, Red-eyed Vireo, Yellow Warbler, American Redstart, Common Yellowthroat, Swamp Sparrow, Bobolink, Red-winged Blackbird, Common Grackle, Brownheaded Cowbird, Orchard Oriole and Northern Oriole. Many of these birds are wetland species. Several, such as Eastern Bluebird, Bobolink, Brown-headed Cowbird, and Orchard Oriole, are grassland, meadow, or orchard species found here because of the surrounding agricultural lands. Migrant birds I have observed stopping over in Durham Meadows are Greater and Lesser Yellowlegs, Solitary Sandpiper, Spotted Sandpiper, Upland Sandpiper, and Common Snipe.
CONNECTICUT RIVER SILVER MAPLE FLOODPLAIN FOREST, ROCKY HILL, CONNECTICUT.
(Topographic Map: Hartford South Quadrangle & Glastonbury Quadrangle, Hartford County, Connecticut) While Red Maple is the dominant tree species of Connecticut’s swamplands, another member of the maple family, Silver Maple (
), is the most abundant tree of floodplain forests. These forested wetlands, called bottomland hardwood forests in the southeastern United States, develop in low-lying areas along major rivers & streams—Connecticut, Thames, Quinnipiac, Naugatuck, and Housatonic. Silver Maples grow to 50-80 feet, fully mature individuals attaining a DBH of 3 feet. Trunks grow twenty or more feet without significant tapering, or lower to the ground they divide into several large forks. Silver Maples are fastgrowing trees, explaining their popularity as residential shade trees.
Fast growth enables silver maples to recolonize floodplain habitat which damaged by sudden, extensive and violent floods. Trunks and branches of Silver Maples are easily broken by strong floods or gale-force winds. Examining a floodplain forest along a major river, one finds many broken or split individual trees. An additional feature of Silver Maple, its ability to send out long, arching branches and for these branches to root in alluvial soils at points of contact or breakage, makes this tree ideally suited for floodplain environments.
Silver Maple shares floodplain habitat with Eastern Cottonwood (
), American Elm (
), and Black Willow (
). Each of these species can exceed 100 feet and 4 feet DBH. They are all fast-growing and generally short-lived. Boxelder (
), a shorter maple family member, also grows in floodplain forests. The Rocky Hill floodplain has abundant patches of Cinnamon Fern (
), Royal Fern (
), Wood Nettle (
), and Garlic Mustard (
). Poison Ivy (Rhus radicans), Virginia Creeper (
), and Riverbank Grape (
) are common vines.
The study site I use for Silver Maple floodplain forest is located along the Connecticut River in Rocky Hill, south of Exit 25 on Interstate 91. The floodplain is found between the 15 foot high banks of the Connecticut River and adjacent farmiands to the west. This region is characterized by “ridge and swale” topography, alternating regions of low deepwater or dried out channels and elevated sandbars populated on their margins by tall trees and having a mixture of trees and herbaceous plants on their highest portions. While you are in a forest, you’re never far from the next open, river-cut swale. To stay dry, you enter a floodplain forest by walking the length of a ridge and cutting across the channel head to the next ridge, or you canoe in.
The silver maple floodplain forest wetland undergoes greater seasonal change than do any of the other wetlands described here. During major spring and summer floods the entire floodplain is submerged by 10 to 20 feet or more of river water. Only upper trunks and crowns of trees are visible. During non-flood stage, back channels (testimony to extensive river channel migration and to the previous locations of the main river channel) are present as dry depressions or deepwater bodies of still water. Mid-June and July visits to the floodplain give a completely different impression of this habitat. In these summer dry periods the channels are vegetated by obligate and facultative hydrophytic plants which grow to substantial heights.
The animal life of the silver maple forest is fascinating. Common Snapping Turtle (
) inhabits the quiet back channels, feeding on a range of fish species. On May 5, I observed a snapping turtle which certainly exceeded the state record of 17.5” carapace length, although I did not attempt to capture this turtle for measurement. (A noticeably smaller snapping turtle captured the same month at Konold’s Pond in Woodbridge had a carapace measured at 16.5”) Snapping Turtle is a major predator of the floodplain forest community. Tracks of river otter indicate this mammal’s presence. It feeds on fish and aquatic invertebrates. Raccoons are present, also. Birds of floodplain forests include Great Blue Heron, Green Heron, woodpeckers, Eastern Bluebird, and many canopy species. Surrounding agricultural lands, while present at considerable expense to the floodplain forest, serve as breeding sites for Bobolink, a declining nesting species of wet meadows and fields. Spring-flooded fields are important for migrating shorebirds—plovers, yellowlegs, peeps.
The Connecticut River floodplain is affected profoundly by agricultural activity. In Rocky Hill and across the river in Glastonbury, vast floodplain acreage has been converted to agriculture—sod farms, corn, peas, and horse radish. The sod grown here typically is shipped to the state of Maine. North of Hartford these fertile fields are used for the growth of tobacco for making cigar wrappers, and in earlier times for the famous Wethersfield onions.
MOHAWK STATE FOREST BLACK SPRUCE BOG, CORNWALL, CONNECTICUT.
(Topographic Map: Cornwall Quadrangle, Litchfield County, Connecticut) Bogs are peat-accumulating wetlands without any significant inflow or outflow of water, which have acid-loving sphagnum mosses as the predominant ground cover. Bogs may be open wetland habitats ringed with trees and shrubs, or dominated throughout by trees. In northern temperate regions bogs usually are remnant glacial lakes and ponds which have filled in extensively with vegetational detritus over the 12,500-14,000 year period since glacial retreat. Connecticut’s bogs are located fairly exclusively in the northwestern and northeastern parts of the state, although there is a Yale University-owned sphagnum bog in nearby Bethany, Connecticut. The representative black spruce bog I have studied is one at Mohawk State Forest south of Route 4. The entrance to this state forest is not more than a few hundred yards west of the Goshen-Cornwall town line. A short boardwalk enters the bog so that visitors can observe bog plants without trampling delicate bog surfaces. This bog is heavily forested with half a dozen species of coniferous and deciduous trees, has a dense shrub layer, and in late spring and summer has an extensive herbaceous layer consisting of sphagnum moss mats, flowering plants, and heavy patches of ferns. The black spruce bog is surrounded by drier upland on which grow a greater diversity of broad-leaved trees, Eastern Hemlock and Eastern White Pine. Bog topography is quite uneven, the numerous windthrow mounds produced during a long history of hurricane and tornado damage.
Characteristic tree species of the black spruce bog in Mohawk State Forest are the conifers Eastern Hemlock (
), Larch or Tamarack (
), Black Spruce (
), and Eastern White Pine (
), and the broad-leaved trees Red Maple and Yellow Birch (
). In the east, Black Spruce grows from Labrador to New England, extending so far south as northern New Jersey. It grows to timberline in mountainous areas, and has one of the most northern distributions of any American tree species.
Herbaceous plants of the black spruce bog include some with rather remarkable adaptations for living in an extremely nitrogen-poor environment. These include the carnivorous Northern Pitcher Plant and the Round-leaved Sundew, two species which have evolved ingenious strategies for capturing and consuming small and large invertebrates. The Pitcher Plant (
) is found from the southeastern United States north to Labrador and Minnesota. It grows from sphagnum mats in scattered locations within the Mohawk State Forest bog. The plant consists of a foot-wide cluster of basal, pitcher-shaped leaves possessing half-dollar sized openings at the top and tapering to pencil-thin bases. The “receiving end” of the pitcher consists of a colorful, aromatic surface covered with fine hairs, feeling like soft bristle to the finger, all pointing downward toward the pitcher base. The unsuspecting fly, ant, or dragonfly which lands on the mouth of the pitcher finds itself obliged to walk downward, in the direction of the hairs. Soon the hairs cease and the insect steps on a smooth, slippery leaf surface, falling into the pitcher bottom. It gets trapped in a pool of rain water and digestive juices from which it cannot extricate itself. Drowning, the insect is digested by the plant, providing a source of nitrogen from its body proteins. Cut open a pitcher plant leaf, and with a dissecting microscope you find a grizzly graveyard of dragonfly heads and wings, beetle carapaces, ant and fly body parts.
Pitcher plants have specially evolved flowers which are pollinated by bees, typically by bumblebees of the genus
. The pitcher plant actually represents a minute ecosystem of organisms which are either predated by this carnivorous plant, eat the plant’s tissues, or are obligate denizens of the pitcher. The range of organisms living within pitcher plant pitchers includes mosquitoes, flies, mites, amphipods, ants, and moths.
A recent study of
pitcher plants has identified 16 species of arthropods which are obligate associates of this bog plant. Obligate species include the following: (1) a mosquito,
, which undergoes larval development in the pitcher’s pool of water; here the larvae consume microscopic organisms and derived nutrients from suspended particulate matter; (2) a midge,
, whose larvae eat other organisms trapped in the pitcher; this organism pupates above the water line of the pitcher; (3) 5 to 6 species of sarcophagid flies, including
, which has been found living only in pitcher plants; (4) two anoetid mites, including
; (5) moths of the genus
, most notably
; this moth lives out all stages of its life cycle in the pitcher, including mate location and copulation, egg-laying, larval development, pupation, and the adult stage. Before pupation, the soon to-be-metamorphosing larva chews a drainage hole in the pitcher plant wall just below where it will form a pupa, so that the pupa remains dry throughout its development—regardless of how much rainwater reaches the pitcher.
Several species of sundew of the genus
are found in Connecticut’s black spruce bogs, most commonly the round-leaved sundew, D. rotundifolia. This plant employs a different strategy for capturing small insects. Its tiny leaves are rayed by thin filaments, each with a sticky drop of liquid at the end. Insects are attracted to the plant, land on a leaf, and are held fast, as a person’s finger might stick to epoxy glue. Special digestive enzymes digest the prey after the leaf closes around the captured organisms. Getting on your hands and knees with a hand lens and examining the sundew up close will reveal the stuck insects or their remains—again a field of carnage.
CALCAREOS RED MAPLE-BLACK ASH-AMERICAN ELM SWAMP, SOUTH CANAAN, CONNECTICUT.
(Topographic maps: Ashley Falls Quadrangle Massachusetts-Connecticut & South Canaan Quadrangle Litchfield County) Robbins Swamp is located in the cold climate of extreme northwestern Connecticut at an elevation of 650 feet. It occupies a valley east of the old Penn Central Railroad line (from which one can gain access) and west of the 1650-1950 foot Canaan Mountains. As with most Connecticut swamps, it contains abundant Red Maple, but other dominant trees are Black Ash (
), a northern species commonly found only in the northwestern part of the state, American Elm (
), and Swamp Birch (
). Black Ash grows in wet soils of swamps and bogs and along streams. It is most likely to be found in colder climates and where soil drainage is poor -exactly those conditions found in Robbins Swamp. In comparison, the Green Ash present in Durham Meadows is found widely distributed throughout Connecticut.
Robbins Swamp is located in the northern Limestone Valley of Connecticut, and there is a large limestone or “marble” quarry located immediately west of the swamp, visible from the study area described here. The swamp is bisected by Swamp Brook, a slow-moving body of water. Mineral input from the brook and the surrounding uplands give Robbins Swamp some of the peat-accumulating properties of a fen. Vegetation of Robbins Swamp includes a number of rare and threatened species of herbaceous plants which grow only in highly alkaline soils. Those plants which are characteristic of or restricted to neutral or alkaline soils include the orchids Yellow Lady’s Slipper (
), whose species name derives from the plant’s growth in calcareous, or calcium carbonate soils developed over limestone bedrock, and Showy Lady’s Slipper (
, state endangered), and Fringed Gentian (
), and Grass-of-Parnassus (
). At least fifteen special concern, threatened or endangered sedge species are found in northwestern Connecticut’s Limestone Valley. Rare woody plants of the Limestone Valley include Shrubby Cinquefoil (
), Swamp Birch, and Tamarack (
). Poison Sumac (
), a medium-sized shrub with celery-like compound leaves highly toxic to the skin, is a common shrub species to be avoided in Robbins Swamp.
The most notable vertebrate species of northwestern Connecticut calcareous wetlands such as Robbins Swamp is the state endangered Bog Turtle (
), a species found in eastern New York, western Massachusetts and western Connecticut, New Jersey, Pennsylvania, Delaware and Maryland. Bog Turtle is thus near its northernmost range extension in Connecticut. Adult Bog Turtles have a carapace length of less than 100mm (4”), making this the smallest turtle species in New England. Bog Turtle has a moderately domed and weakly keeled carapace, pyramidal carapace scutes, and an orange or yellow patch on either side of the head. The oblong carapace is light brown, and the plastron is brownish black with yellow midline.
Bog Turtle presents a number of conservation challenges, as its highly specialized habitat requirements (open-canopy wet meadows and fens alongside narrow or slow-moving rivers where soil is kept saturated by the steady flow of sheet water) make it vulnerable to any habitat alteration. The preferred wet meadows and fens are sensitive to water quality degradation from fertilizer and septic runoff into feeder streams, introduced wetland plants such as Purple Loosestrife (Lvthrum salicaria), drainage or flooding from stream disruptions, and chemical and heavy metal pollution. High nutrient input into wet meadows and fens results in more rapid growth of red maple which closes the canopy and makes the habitat unsuitable for Bog Turtle. Bog Turtle is considered highly endangered in the state of Connecticut. The Nature Conservancy of Connecticut maintains ownership of Robbins Swamp, managing the site to protect its high number of rare plants.
ATLANTIC WHITE CEDAR SWAMP, NEW LONDON COUHTY, CONNECTICUT.
(Topographic Maps: Old Mystic Quadrangle, New London County, Connecticut & Ashaway Quadrangle, Rhode Island-Connecticut; Wellfleet Quadrangle, Barnstable County, Massachusetts) Atlantic White Cedar Swamps, in which the Atlantic White Cedar (
) is the dominant tree species, are restricted to the Atlantic seaboard from northern Florida to Cape Cod, Massachusetts and, rarely, to coastal New Hampshire and southern Maine. These swamps develop in highly acidic, peat soils in glacially carved depressions which intersect the water table. They are characterized by deep peaty deposits 20-50 feet in thickness which have developed since deglaciation. Connecticut’s Atlantic White Cedar Swamps visited for this study were a swamp north of Route 80 and west of Chatfield Hollow State Park in North Madison (owned by the South Central Connecticut Regional Water Authority), an extensive cedar swamp immediately adjacent to the main parking lot at Foxwood Resort & Casino off Route 2 in Ledyard, Assekonk Swamp south of Route 2 in North Stonington, and Bell Cedar Swamp, north of Route 184 and also in North Stonington. The slide collection is based on photographic work in the Atlantic White Cedar Swamp at the Marconi site, Wellfleet, Massachusetts in Cape Cod National Seashore. The Cape Cod cedar swamp has a boardwalk running through the wetland and is an important interpretive site for Seashore educational and recreational activities. This site is similar to cedar swamps in Connecticut.
Atlantic White Cedar Swamps resemble forested bogs in appearance, with white cedar trees and red maple trees growing in dense stands from windthrow mounds. There is a well developed shrub layer, with Sweet Pepperbush (
), Highbush Blueberry (
), and Inkberry (Ilex glabra) predominating. Sphagnum moss (
) is the principal ground cover, forming lush green carpets throughout the swamp and resting on the deep layers of peat, the dead, partially decomposed remains of earlier sphagnum layers. When the water table is high, as in spring or after heavy summer rains, the swamp floor is covered with sodden mats of sphagnum and has areas of pooled water. In conditions of drought, one can walk through cedar swamps and stay relatively dry. The abundance of decaying vegetable matter turns the pools of water a tea brown color.
Since early colonial times Atlantic White Cedar swamps have been logged for their valuable wood. The wood is extremely rot-resistant and is best known for use as building shingles. The uniquely American Cape Cod saltbox house is usually covered with cedar shingles. The wood is light brown to red-brown in color, and it weathers to a pleasing gray. It is ideally suited to withstanding coastal New England hurricanes, norteasters, and a steady rain of salt spray. White Cedar Swamps are a critical forested wetland habitat which has declined severely in distribution over the past several centuries due to extensive clearcut logging and drainage for conversion to agricultural uses. Connecticut has a number of well-developed white cedar swamps, although in our state also, cedar wetlands have been filled in or converted to other uses. In New England, many of these swamps have been converted to cranberry bogs. Extant white cedar swamps in Connecticut are located in approximately 20 different towns, mostly in New London County.
The Atlantic White Cedar is a tree species with highly specialized growth requirements. White cedars are fairly slow-growing, longlived species which historically grew to large size but which are generally restricted to small- to medium-sized trees today. They are capable of colonizing fire-, hurricane- or logging-disturbed sites successfully, outcompeting such hardwood trees as Red Maple. They are, however, dependent on regular disturbances occurring approximately in a twenty year cycle in order to maintain their dominance in the swamp forest. Cedars are more resistant to fire than are red maples, and even if they are killed by fire they will seed in and initially outgrow red maple seedlings. They similarly fill in clearcut swamps faster than do maples. If Red Maple is given extended opportunity to grow, as in long-undisturbed sites, it will overtop the cedars, cause them to die, and cut off the regeneration of younger cedar trees. Lie down on a boardwalk in an Atlantic White Cedar swamp, look straight up, and you can see that Red Maple stretches and bends to fill all available gaps in the swamp canopy. Mature maples also overtop the cedar canopy.
The predominant forest management strategy of past decades has been fire suppression, a disruption of the natural cycle of cedar swamp disturbance resulting in cedar swamps which year by year approach a condition of replacement by Red Maple swamp. Cape Cod National Seashore, the Regional Water Authority, and private landholders such as the Mashantucket Pequots will face decisions on whether to disturb and preserve existing cedar swamps or see them disappear.
Vertebrate life is less apparent to the observer in cedar swamps than in other forested wetlands, in part because of the near monoculture nature of these stands—impeding biological diversity and in part because of the shortage of available food for wildlife. The one notable exception to this is the widespread presence of Highbush Blueberry in cedar swamps. Representative raptorial birds of the swamp include Red-shouldered Hawk (
) a nester in swampy woodlands, Barred Owl (
—not found on Cape Cod) which occupies abandoned Red-shouldered Hawk nests, and Northern Sawwhet Owl (
). Several woodpecker species are found in cedar swamps, as are such perching birds as Tufted Titmouse and Blackcapped Chickadee. In comparison, the surrounding upland forest always seems to teem with a broad diversity of mixed canopy species. Whitetailed Deer can negotiate cedar swamps, and gray and red squirrels and a variety of smaller rodents live here.