An understanding of the functions of the intertidal emergent wetlands of the 

 estuarine system is valuable to the overall understanding of the ecology of 

 the Maine coast ecosystem. Estuarine emergent wetlands represent a fragile 

 and highly productive community. 



In Maine, estuarine emergent wetlands are dominated by three persistent 

 species: salt marsh cordgrass ( Spartina alternif lora ) , salt hay ( Spartina 

 patens ) , and black rush ( Juncus gerardii ) . Intertidal emergent wetlands that 

 are characterized by these species are called salt marshes. The term salt 

 marsh can be subdivided into two categories: (1) low marsh, generally 

 dominated by the regularly inundated cordgrass; and (2) high marsh, 

 irregularly flooded areas dominated by salt hay and black rush. 



The importance and roles of the estuarine intertidal emergent wetlands and the 

 estuarine intertidal subsystem in areas outside Maine have been well 

 documented (Odum 1961; Teal 1962; Niering 1966; Cooper 1969; Redfield 1972; 

 Gosselink et al. 1974; Wiegart et al. 1975; and Chapman 1977). Only a few 

 researchers (Vadas et al. 1976; Linthurst 1977; Linthurst and Reimold 1978; 

 Keser et al. 1978; and McGovern et al., in press ) have attempted to 

 characterize the ecology of salt marshes in Maine. Consequently, when 

 reviewing the characteristics and interactions of Maine's intertidal wetlands 

 it is often necessary to draw from research on similar intertidal wetland 

 systems in other New England States. 



Descriptions of the physical and biological features and physical/biological 

 interactions in Maine's estuarine emergent wetlands are given below. 



The two physical features which most influence the natural history of the 

 estuarine intertidal salt marsh habitat are geology and hydrography. The 

 contributed effects (e.g., icing and storm tides) of climate are discussed 

 above. 



Coastal Maine possesses a unique geological history that is reflected in its 

 distinctive physiographic structure. Glaciation helped create a coastal 

 ecosystem characterized by long, deep, steep shores and rocky headlands. The 

 geological foundation, formation, evolution, and overall physical structure of 

 the intertidal salt marsh in Maine is discussed under "Geology" above. 



Hydrographic parameters are important in determining the distribution of 

 intertidal salt marshes. Tidal inundation, frequency, and duration, and 

 salinity are the most important hydrographic parameters that influence salt 

 marshes. The process driving succession and the effects of both geology and 

 hydrology on plant distribution are discussed below. 



The physical features of the characterization area are much different from 

 those of southwestern coastal Maine, New Hampshire, and other States in New 

 England. In general, the steep nearshore-to-upland relief, lack of suitable 

 sedimentary material (usually deposited by rivers), and relatively high energy 

 tidal currents, limit the formation of intertidal wetlands. In Maine, 

 intertidal wetlands tend to be small, contiguous, fringing in nature, and 

 located in drowned sediment-filled valleys of estuaries, as in the Sheepscot 

 River drainage (Vadas et al. 1976; see atlas map 1). 



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