by Dorcas Coleman|
According to lore, Maryland’s March bellows in like a beast snarling through hoops of fire and exits as some sweet confection wrapped in brightly colored foil and placed inside a child’s Easter basket. With each passing day the sun climbs a little higher in the sky and the dark, dull tones of winter begin to give way to green shoots and buds, popping out from twigs and branches and softening brown soil.
And perhaps nowhere is this more apparent than in the odd, watery holes nestled among forest and field along the Delmarva peninsula. These unassuming depressions are the Delmarva bays, long the red-headed stepchildren of the state’s network of wetland communities. For these ecological marvels, their time has come.
Driving north on MD Route 213 through Queen Anne’s and Kent counties, one is easily lulled by seemingly endless miles of agricultural fields, broken up by small clusters of houses here and there. But turn down an east bound side road - Rt. 305 or 300 or 291, perhaps - and off on the horizon lies a wall of forest, running north-south as far as the eye can see. This is Crescent Preserve, a soggy yet verdant region of seasonally flooded, wooded wetlands and an area pockmarked by thousands of Delmarva bays.
Elliptical depressions with distinct sandy rims, the value of these subtle aberrations in the Shore’s topography has long been underestimated. Part of the phenomenon of Carolina bays, seasonally flooded upland depressions found in an arc from New Jersey to Georgia, they once numbered between 1,500 and 2,500 on the Shore. Many have since been destroyed, however, through clearing and contouring the land for farming purposes.
Known by a variety of colorful terms - potholes, kettles, sinkholes, whale wallows, round ponds, black bottoms and loblollies - their origin is still the subject of considerable controversy. An appealing but improbable idea suggests that primeval whales, stranded by shallow receding seas, were left to wallow helplessly, thus creating the depressions. Others include ancient meteorite impact and the melting of stranded ice debris following the last Ice Age.
What is known is that the Delmarva bays are part of an extensive sand dune wetland ecosystem, the bays being the actual interdunal depressions. They are estimated to be 16,000 to 21,000 years old, probably forming when the peninsula’s climate was similar to that of the Siberian taiga - cold, sandy and very, very windy.
Delmarva bays are in every sense of the word geological and biological enigmas. Seasonally flooded, they are formed from rainwater or snow melt in late winter, drying out by late summer. Unlike marshes, they are fed by rain and groundwater only; there is no natural drainage into or out of them. Their entire ecosystem is dependent upon the natural fluctuation of rain and the water table.
Although they are not covered by water year round, Delmarva bays are classified as wetlands -- areas that hold water for significant periods during the year, characterized by anaerobic (low oxygen) conditions favoring the growth of specific plant species and the formation of specific soil types. While wetland communities vary dramatically, all are important natural resources providing fish and wildlife habitat, flood protection, erosion control and water quality preservation.
According to the 1995 National Wetlands Inventory survey, about 10 percent of Maryland is classified as wetland. They are most abundant on the Eastern Shore, occupying 16 percent of the land area. The majority are non-tidal palustrine (freshwater wetlands, which lack flowing water), representing 57 percent of the State’s total, about 342,626 acres.
Considered non tidal wetlands of Special State Concern, Delmarva bays are designated for special protection under Maryland’s non- tidal wetland regulations. Like many other special wetlands, these bays contain some of the last remaining populations of native plants and animals that are now threatened with extinction in the state.
Maryland has lost roughly half of its original wetlands and Delmarva Bays have been particularly hard hit. The most humble of wetlands - sometimes little more than glorified puddles - to the untrained eye a Delmarva bay would be unrecognizable, particularly during the summer or fall months. Averaging 3 acres, with some being as large as 15 acres, most are small and easily overlooked. Because they often lie unprotected on private lands, they are sometimes destroyed even before being discovered.
Over the years, many bays have been drained and contoured for agricultural purposes, while others have been built upon, bulldozed or paved over without anyone knowing the ponds were present. These natural depressions have also been turned into stormwater ponds to receive runoff from nearby roads and parking lots, which can be extremely detrimental to a bay’s inhabitants.
Fertile Breeding Ground
Nesting colonies of green herons, great blue herons, and various species of waterfowl, feed on the animals and plants that come to life when the pond is full of water. As the water dries up, several of these species then become dormant, forming protective coverings or burrowing into the drying mud until the pond fills again. Some plants die back, leaving their seeds to germinate during the next wet season, while others like the Canby’s dropwort and Harper’s sedge, both state endangered and nationally rare, emerge from seeds in the damp, exposed soil.
Delmarva bays also provide both a breeding ground and nursery to many imperiled species, foremost among them amphibians, a group of animals in decline worldwide. Rare Eastern tiger salamanders, seldom seen above ground, slither out of their subterranean dens each winter to breed and lay eggs, often under ice, while the endangered barking tree frog and the threatened carpenter frog await the warmer weather of spring and summer to breed in the bays.
What lures these reclusive creatures to the bays as opposed to other bodies of water is exactly what these temporary ponds lack: fish. Because the bays dry up every year, they cannot support fish, which leaves these amphibians to breed in relative safety.
Unlike fish, salamanders and frogs are only water dwellers for part of their lives. They spend their first two to five months as larvae, swimming in the bays and feeding throughout the night. When the pools begin to dry out in the summer, the larvae reabsorb their gills and tail fins and emerge from the water, spending the remainder of their lives on land.
Among the other Delmarva bay breeders is the spring peeper. Like the salamanders, they congregate in the water in late winter and spring, where they mate and lay gelatinous eggs. The Shore’s fields and forests offer a cacophony of sound for the region’s residents as spring evenings warm and bedroom windows open. The peepers' chorus of croaks and creaks not only serve to announce the season but often reveals the location of more remote bays. Many insects, especially mosquitoes, also breed in the bays, which in turn attract dragonflies, damselflies, frogs and toads to feed while the water lasts.
June arrives, local girls will marry, emerald green corn will rocket up and begin to get leggy by month’s end. And as unceremoniously as they formed, the bays will begin to disappear. As the plentiful spring rains give way to the typical thirsty Maryland summer, the bays will dry up, leaving nothing more than a slight pocket in the contour of the otherwise flat Delmarva landscape.
For the residents of the Crescent Preserve whose front yards have been swamped with water for several cold, dank months, this will come as a relief. But look beyond the obvious. For as the year wanes and another commences, the Delmarva bays will once again flood and emerge as vitally important, albeit often invisible, worlds of their own.
The Maryland Department of Natural Resources, in conjunction with the Nature Conservancy, is currently monitoring several Delmarva bay complexes in the Crescent Preserve. Studies are underway to link these sites in an attempt to preserve and protect the unique biodiversity of the region’s flora and fauna.
Like to see a Delmarva bay? The 3,800-acre Millington Wildlife Management Area in Kent County is home to numerous bays and is rich in history as the former home of the Lenni Lenape Indians. Many trails wind through the area’s forests and fields and are open year-round for hiking. For additional information, contact the Millington Work Center at (410) 928-3650 or check it out on the DNR website at www.dnr.state.md.us/publiclands/eastern/millington.html
Dorcas Coleman is a staff writer in DNR's Public Communications Office and assistant editor of this publication.
Photos were taken by state restoration ecologist R. Wayne Tyndall, who also graciously shared his vast knowledge and expertise on the subject for this article.