The coastal bays watershed has lost nearly three quarters of its historic forest and wetland habitat since colonial times. Although the rate has slowed considerably in recent years, concern exists that new development resulting from tourist and residential growth projections may once again increase the loss of valuable coastal bays’ habitat.

Although some impacts may be irreversible, natural processes such as forest regrowth, reestablishment of sea grass beds, and succession of vegetation in wetland areas have partially reduced the environmental consequences of some habitat loss. While recovery of some bay bottom habitats may take a year or two, recovery of forested wetlands may take decades. Other habitat losses, like urban neighborhoods built on a salt marsh, will be essentially permanent.

Habitat loss and alteration have direct and indirect effects on the coastal bays’ ecology. While habitat loss reduces space, food, and other resources available to plants, fish, and wildlife, destruction of certain habitats may have disproportionate effects. For example, destruction of wetlands and salt marshes decreases their ability to filter nutrients and sediment from surface runoff and groundwater, and deprives waterfowl and shorebirds of important foraging and resting areas. Loss of sea grass beds not only deprives marine species of habitat and food sources, but also exacerbates sediment resuspension problems and increases shoreline erosion from wave action.

A number of activities cause habitat loss including residential and commercial development, marina and boat slip construction, dredging, draining and clearing of wetlands and forest for agriculture and development, shellfish harvesting, bulkheading, boating, erosion and overwash of the north end of Assateague Island. Even the Assateague ponies contribute their share by grazing in the salt marshes.

Forests

While forests and wetlands are still the predominant land use, most of today’s forests are intermixed with agricultural and urban lands, which account for approximately 43% of the watershed’s land area. Unfortunately, the value of forest as habitat for native wildlife is still being reduced as fragmentation reduces a few large forests to many smaller ones. Loss of riparian forests is also harmful because these areas serve as filters that remove sediment, nutrients and some chemical contaminants from surface runoff and groundwater before they reach the bays. Riparian forests also serve as critical habitats to many terrestrial and aquatic species.

Wetlands

Freshwater and estuarine wetlands improve water quality, reduce the frequency and severity of flooding, and provide habitat for waterfowl and other wildlife. Wetlands also store and reduce surface water flows and act as groundwater discharge or recharge areas in addition to trapping sediments and nutrients before they enter the coastal bays.

Since settlement of the area began, an estimated 21,000 areas of forested wetlands within the watershed have been drained and cleared for agriculture with approximately 4,000 areas drained for development. Loss of tidal wetlands since the 1930s are estimated to be between 1,575 and 2,115 areas; however, legislative actions such as Maryland’s Tidal Wetlands Protection Act and the Federal Clean Water Act have slowed but not stopped the process. Since 1991 permits to drain and alter wetlands have been issued for 20 acres of non-tidal wetlands in the coastal bays watershed. Most of these permits were associated with urban development in areas platted before the wetlands protection laws were enacted. Mitigation of developed wetlands since 1991 has reduced the net loss to about four acres.

Subtidal Habitats

Large-scale impacts on subtidal habitats are most significant in the northern bays where extensive navigation improvements have occurred. The Army Corps of Engineers estimates that 330 acres of bay bottom have been dredged for navigation, another 185 acres dredged to acquire fill material to restore Ocean City and Assateague Island beaches, and an estimated 520 acres have been filled by accelerated sediment overwash into Sinepuxent Bay from the stabilization of Ocean City’s inlet.

There is also concern about potential impacts on sea grass beds and other bottom habitats from recreational boaters and commercial shellfish harvesting. Propeller wash, boat groundings, and boat wakes can disturb the bay bottom, resuspend sediments and chemical contaminants, uproot sea grasses, and accelerate shoreline erosion. The noise recreational boats make in shallow waters nearer shore is also a concern.

Oyster reefs--hard-bottom communities that are also home to many fish and invertebrate species that live on or near the oyster bar--are also in danger. A combination of disease, eutrophication, and over fishing has reduced oyster habitat in Chincoteague Bay to 200 acres today from more than 2,000 acres a century ago.

Shoreline Habitat

Shoreline protection efforts in the coastal bays have produced miles of bulkhead and stone revetments (rip-rap). While bulkheads effectively protect shorelines from erosion they reflect rather than absorb waves which accelerates erosion and sediment suspension in nearby areas. Bulkheads also provide little cover for fish and shellfish.

Conversely, stone revetments dissipate wave energy on a gradual slope or among the rocks. Crevices and cracks in the rocks also provide hiding places for marine life. Although preferable to bulkheads, revetments exacerbate natural shoreline loss and can eliminate the supply of sediment that maintains beach and shallow water habitats. Salt marsh plantings, on the other hand, limit erosion as well as provide valuable habitat for fish, wading birds, and invertebrates in moderate to low-energy applications.

Monitoring Data on DNR's website.