Northeast Coastal Areas Study
Significant Coastal Habitats
Site 35 (MA)
I. SITE NAME: Sippewisset Marshes
II. LOCATION: Located along the lower eastern Buzzards Bay shoreline of Cape Cod, approximately 5 miles (8 km) north of Woods Hole and 1 mile (2 km) southwest of West Falmouth.
USGS 7.5 MIN QUAD: Woods Hole, Mass 41070-56
USGS 30x60 MIN QUAD: New Bedford 41070-E1
III. GENERAL BOUNDARY: This saltmarsh area consists of Great Sippewisset Marsh to the north and Little Sippewisset Marsh to the south, separated from each other by a narrow tongue of land (Saconesset Hills). The entire area is about 1.5 miles (2 km) long in a north-south direction and ranges in width (east-west) from 0.25 to just under 1 mile (0.5-2 km). The boundary is delineated on the accompanying map and includes a narrow stretch of sand beaches and nearshore waters of Buzzards Bay.
IV. OWNERSHIP/PROTECTED STATUS: Ownership in this area consists of private and Town-owned lands.
V. GENERAL HABITAT DESCRIPTION: This classic New England salt marsh has two distinct grass communities: low marsh, in which the sediments are covered by water on most high tides, characterized primarily by saltmarsh cordgrass (Spartina alterniflora); and high marsh, lying above mean high tide level and dominated by salt meadow cordgrass (Spartina patens) and spikegrass (Distichlis spicata). Black grass (Juncus gerardii) is distributed mainly in a narrow fringe along the landward edge of the high marsh. These two types are often referred to as regularly flooded and infrequently flooded marshes, respectively. Saltmarsh cordgrass growing on regularly flooded low marshes of this area occurs in two growth forms, tall and short. The tall form, between 4-7 ft (1.25 to 2 meters) in height, grows along the banks of the tidal creeks and on areas where marsh sediments are actively accumulating and the marsh is building outward. The short form is found over the remaining low marsh areas and may be as short as 4 inches (10 cm) in height. The low marsh is almost a monoculture of saltmarsh cordgrass, although a few other species of higher plants also commonly occur here, including glassworts (Salicornia spp.) and sea lavender (Limonium nashii), and several species of macro- and microscopic algae, especially knotted wrack (Ascophyllum nodosum), sea lettuce (Ulva lactuca) and green fleece (Codium fragile). The invertebrate fauna includes two species of fiddler crabs (Uca pugilator and U. pugnax), common periwinkle (Littorina littorea), salt marsh snail (Melampus bidentatus) and ribbed mussels (Modiolus demissa). Spiders and grasshoppers are generally very abundant. Many migrant and resident birds frequent these marshes, including several species of waterfowl, shorebirds, sparrows, warblers and others. Fishes of these salt marshes can be divided into two groups: 1) relatively permanent residents such as mummichog (Fundulus heteroclitus), Atlantic silverside (Menidia menidia) and sheepshead minnow (Cyprinodon variegatus); and 2) those that use the marshes mostly as a nursery area, such as winter flounder (Pseudopleuronectes americanus), menhaden (Brevoortia tyrannus), tautog (Tautoga onitis), American sandlance (Ammodytes americanus), striped bass (Morone saxatilis) and bluefish (Pomatomus saltatrix).
VI. SIGNIFICANCE/UNIQUENESS OF AREA: One of the most significant characteristics of the Sippewisset Marshes is their relatively pristine, unditched condition, a rarity among New England and New York coastal marshes, particularly of this size. It is primarily for this reason that these marshes have been the subject of a great many field research studies on all aspects of salt marsh structure and function conducted by scientists at Woods Hole Oceanographic Institution and the Boston University Marine Program, Marine Biological Laboratory in Woods Hole, Massachusetts, and other universities. Their value as a baseline and standard for salt marsh studies and characterizations for over 20 years is unsurpassed in the region. A community profile on the ecology of regularly flooded salt marshes of New England, published by the U.S. Fish and Wildlife Service in 1986, is based primarily on Great Sippewisset Marsh.
These marshes are used extensively by American black duck (Anas rubripes) in winter, which feed primarily on salt marsh snails that climb on the stalks of cordgrass, while wintering flocks of snow geese (Chen caerulescens) and Canada geese (Branta canadensis) graze on the stems of saltmarsh cordgrass. Ospreys (Pandion haliaetus), terns, herons, egrets and bitterns feed on various fish along the edge of the marsh and in the tidal creeks. Piping plovers (Charadrius melodus), a U.S. Threatened species, nested not too long ago on Black Beach in this complex, but not in recent years. Nearby waters of Buzzards Bay are important feeding areas for roseate tern (Sterna dougallii), a U.S. Endangered species, that nest on Bird Island across the Bay to the northwest. Northern diamondback terrapin (Malaclemys t. terrapin) feed and nest in these marshes and sandy borders. These marshes and adjacent shallow waters and creeks are critical nursery areas for a number of commercially important fish species, including winter flounder, bluefish, striped bass and tautog. Saltpond grass (Diplachne maritima), a regionally rare grass species, has been recorded from the general area in recent times, as has bushy rockrose (Helianthemum dumosum) on nearby uplands.
VII. THREATS: Because much of this area is privately owned and the population of Cape Cod continues to grow at a tremendous rate, far above that of the general region as a whole, there is considerable development pressure adjacent to these marshes. In addition to potential loss of habitat, residential and marina development along the shoreline and adjacent uplands could threaten the water quality of both groundwater and surface waters in this area. Degradation of waters, including excessive nutrient loading, can potentially lead to vegetation and faunal changes in the marshes and adjacent waters and impact the suitability of this area for those fish and wildlife species now using the area. Disturbance of piping plover nesting areas by human and pet incursions are a serious problem throughout the region and have led to the abandonment of many former piping plover and tern colonies. The lack of any recent breeding activity on beaches in this area may possibly be the result of human-related disturbances.
VIII. CONSERVATION CONSIDERATIONS: Strategies and opportunities should be sought and developed for the long-term protection of the regionally important fish, wildlife, ecological, educational and scientific values of this marsh complex, using whatever cooperative or regulatory land and water protection and management means that might be available. Such measures might include the development and implementation of cooperative conservation and management agreements among the various multiple private landowners and Federal, State and local governmental agencies, private conservation organizations and the research/educational community at Woods Hole to ensure the protection of these marshes and the water quality of this area. Other measures to consider include promulgation and enforcement of stringent environmental and land-use zoning policies and regulations, and seeking conservation easements, land exchanges, and, in some cases, acquisition of particularly important or vulnerable tracts. Water quality needs to be closely monitored, enhanced and protected. Human intrusions into beach nesting areas of terns or piping plovers should be prevented throughout the critical nesting season (mid-April to August), and efforts made to enhance the suitability and recolonization potential of the former piping plover nesting area on Black Beach. Disturbances to nesting Northern diamondback terrapins also needs to be assessed and measures implemented to protect nesting areas and individuals.
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