ECOLOGY OF BUZZARDS BAY: An Estuarine Profile 



67 



(Cancer irroratus), green crab {Carcinus 

 maenas), and blue crab (Callinectes sapidus); 

 these species migrate on and off the flats with the 

 tide, feeding on submerged bivalves and annelids. 

 The lady or calico crab (Ovalipes ocellatus) fre- 

 quently buries itself in the sandy sediments of these 

 flats. Hermit crabs (Pagurus longicarpus and P. 

 pollicaris) and snails (Ilyanassa and Nassarius) 

 also coexist on the tidal flats; the hermit crabs utilize 

 the empty shells of the snails for semipermanent 

 homes. The horseshoe crab frequently uses the tidal 

 flats as feeding and spawning grounds and deposits 

 its eggs at the high water line. As with marshland. 

 Westport has the largest areas of tidal flat and bar- 

 rier beach within Buzzards Bay. Additional infor- 

 mation on New England tidal flat communities can 

 be found in Whitlatch ( 1 982). 



4.3. Terrestrial 



The physical processes that formed Buzzards 

 Bay not only led to a wide variety of marine envi- 

 ronments but also resulted in a diversity of land 

 forms, habitats, and natural resources within its up- 

 land regions. Human activities within the watershed 

 area over the past several centuries, however, have 

 significantly altered the structure and composition 

 of many of these terrestrial systems. 



Numerous kettle ponds, common to pitted 

 outwash plains such as Buzzards Bay, are a domi- 

 nant feature of the landscape. These deep ponds 

 were formed when large blocks of ice left by the 

 retreating glaciers were buried by glacial debris and 

 outwash sands that collapsed as the ice melted, leav- 

 ing the depressions. When the base of the depres- 

 sion was below the water table, a pond was formed. 

 Many of these ponds support freshwater marshes, 

 typically dominated by Typha and Phragmites, and 

 provide important habitat for many species of 

 animals. 



Other freshwater environments within the Buz- 

 zards Bay watershed, like the freshwater marshes, 

 are structured by the amount and duration of fresh- 

 water saturation. Critical habitats such as sphag- 

 num bogs, cedar swamps, and vernal pools dot the 



landscape around the bay. Sphagnum bogs are simi- 

 lar to marshes in that they become established in 

 areas of persistently saturated soils. These bogs are 

 dominated by Sphagnum spp. or "peat" mosses 

 and low-growing shrubs like cranberry ( Vaccinium 

 macrocarpon). The live sphagnum or peat mosses 

 grow in thick mats overlying deep layers of accu- 

 mulated peat. A very fragile system, these bogs of- 

 ten support a variety of rare and unusual plants 

 such as wild orchids and carnivorous plants such as 

 sundews (Droscra sp.). Sphagnum bogs can be 

 found around the bay. notably in Falmouth 

 (Chappaquoit) and Bourne (near the railroad 

 bridge). 



Like sphagnum bogs, cedar swamps, which are 

 dominated by the Atlantic white cedar 

 (Chamaecyparis thyoides), highbush blueberry 

 (Vaccinium corymbosum), and swamp azalea 

 (Rhododendron viscosum), occur in areas of satu- 

 rated soils and acidic waters that affect decompo- 

 sition and nutrient availability. The white cedar 

 swamp is commonly found along with red maples 

 (Acer rubrum), which often restrict the extent of 

 white cedar growth. These cedar swamps can be 

 found in pockets or associated with cranberry bogs 

 around Buzzards Bay. in Bourne (east of the Bourne 

 Bridge) and Falmouth (east of Woods Hole and 

 east of Little Sippewissett Marsh in West Falmouth), 

 but most notably in the Acushnet Cedar Swamp in 

 New Bedford and Dartmouth, considered to be one 

 of the last truly wilderness areas in southeastern 

 Massachusetts. Cedar swamps, like huckleberry and 

 maple swamps, were historically much more abun- 

 dant but were cleared and diked to form many of 

 the existing cranberry bogs, which is the dominant 

 agriculture of the region (White 1870; Thomas 

 1990). Cranberry bogs require damp but not satu- 

 rated soils for best production, conditions found in 

 many of the swamp forests. Some attempts were 

 made by the early settlers to conserve the white 

 cedar swamps because their wood was used in the 

 construction of moisture-proof foundations and for 

 the cedar shingles prevalent on many houses in the 

 region. The diminished availability of firewood with 

 progressive deforestation, however, increased the 



