emergent salt marsh: (1) water content, (2) water table, (3) fluctuation of 

 water levels, (4) soil types, (5) aeration, (6) nutrients, (7) acidity, (8) 

 salinity, (9) temperature, (10) light, and (11) chemistry. Biotic forces 

 include animal actions, plant competition, and human activities. 



In Maine the sharp physiography between subtidal and terrestrial habitats 

 tends to compact the salt marsh and enhance zonation. Two zones can be 

 characterized (figure 5-44); (1) the low marsh, which is regularly flooded by 

 the tides and dominated by smooth cordgrass; (2) the high marsh, which is 

 irregularly flooded by the tides and dominated by salt hay, with black rush 

 dominating along the highest fringe of the marsh. Above the black rush zone a 

 variety of transitional and terrestrial species may be found as the influence 

 of tidal inundation and salinity becomes markedly reduced. The macrophytes 

 most commonly found in Maine salt marshes and their habitat preferences are 

 listed in table 5-15. 



The low intertidal marsh zone in Maine is dominated by salt marsh cordgrass. 

 Smooth cordgrass is a stout marsh grass with long, smooth, tough leaf blades 

 and strong creeping rhizomes. It usually grows in dense stands in the low 

 marsh. It tends to occur in a tall form near the water edge, followed by a 

 shorter "dwarf" form farther up the marsh. 



TIDAL MARSH 



IfTik 



I 



Panicum virgatum 



>\ 



Juncus 



> Upland u land Upper I 



'" TL Shrub i Border I Upper Slope 



*^^jT' Border , ^ . , 



«\l„5*^ ' Exceptions! 



Spartina patens 

 I Lower Slope 



Spartina alterniflora 

 Lower Border 



Figure 5-44. Cross section of an upland-to-bay sequence in a New England 

 salt marsh showing intertidal high and low marsh (adapted 

 from Miller and Egler 1950). 



5-115 



10-80 



