LET'S VISIT A SALT MARSH 
     
    
   
   
    
       
     
    
   
   
    
       
     
    
   
   
    
     At the mere mention of a salt marsh many of us quickly turn up our noses, with 
     
     visions of dank sultry places swarming with hordes of ravenous mosquitoes. However 
     
     our ancestors viewed salt marshes quite differently and rapidly recognized their 
     
     value as pasture land. Today we see little obvious commercial importance in our 
     
     coastal marshes but they certainly are fascinating places for a naturalist. 
     
    

    
     On the Island there are several thousand acres of salt marsh. These usually 
     
     are found in sheltered coves, behind-a barrier beach system, or in estuaries where 
     
     salt and fresh water mix. Salt marshes form where shallow coastal waters receive 
     
     sediment deposits carried by the tides. As silt loads accumulate upward, tidal flats 
     
     eventually become exposed at low tides, permitting colonization by land plants. With 
     
     the growth of marsh vegetation, leaves, stems and roots help to catch and hold even 
     
     more sediment. 
     
    

    
     Silt laden waters flooding over the marsh are slowed by the vegetation and soon 
     
     drop much of their load. This can cause the seaward edge of the marsh to become 
     
     higher than landward portions. Needing drainage routes ebbing tide waters gradually 
     
     cut a pattern of tidal creeks across the marsh surface. Ice scouring in winter, 
     
    

    
     ' slumping of saturated creek banks to block drainage, and settling of algal mats to 
     
     create shallow depressions and pools all work to further influence marsh topography. 
     
    

    
     To live in a salt marsh plants must overcome many difficulties. These include 
     
     battering by storm tides, innundation by silt, soil with low oxygen content, and 
     
     large temperature, salinity and moisture fluctuations. Because of the physical 
     
     problems of the marsh habitat a relatively small number of plants has developed the 
     
     necessary adaptations for dwelling there. A large part of the marsh surface is 
     
     dominated by fairly pure stands of only one or two species. These are arranged in 
     
     distinct bands or zones, and are quite readily identifiable by colour even from a 
     
     distance. 
     
    

    
     Below the seaward edge of the marsh lie tidal flats of bare mud. Above, a small 
     
     bank marks the transition to vegetated marsh dominated by salt water cord grass 
     
     (Spartina alterniflora). This tall tough grass provides the characteristic fresh 
     
     greenness of marsh vegetation. Landward from.the broad cord grass zone lies a 
     
     narrower band of salt marsh hay (Spartina patens). This fine hair-like grass was 
     
     in earlier days prized for livestock fodder. The weak stems of salt marsh hay allow 
     
     the winds to flatten it into swirled mats. This upper zone of the marsh is often 
     
     poorly drained, thus permitting the formation of shallow pools. Around and above 
     
     these, two more typically freshwater species sometimes occur: the coarse yellow— 
     
     green sedge Carex paleacea and the dark green rush Juncus balticus. These four 
     
     perennial grasswtype plants and especially the Spartinas have extensive root systems 
     
     penetrating into the marsh soils. Although their above ground parts are scoured 
     
     away by winter ice, the sturdy roots hold the marsh together as a firm sod. 
     
    

    
     Where, for whatever reason, the cover of the dominant grasses has been destroyed, 
     
     several salt tolerant annuals are quick to take advantage. Samphire (Salicornia 
     
     europa), a small stubby plant whose leaves and stems have a swollen succulent 
     
     appearance, is quick to move in on the bare mud surface. Easily recognized by its 
     
     fiery red colour of late summer, samphire is eaten as tasty greens earlier in the 
     
     season. Sea lavender (Limonium nashii) prefers the more elevated sites provided 
     
     when retreating winter ice deposits large clods of sod on the marsh surface. In 
     
     late summer sea lavender blossoms into a mass of tiny lilac flowers which are 
     
     excellent for dried arrangements. 
     
    

    
     Two other showy salt tolerant species found along the upland edges of salt 
     
     marshes are seaside goldenrod (Solidago sempervirens) and Scotch lovage. Sometimes 
     
     the upper edges of mature salt marshes merge with brackish and fresh water marsh 
     
     systems, and here cat tails, bulrushes and a host‘of other more inland plants may 
     
    
   
   
    
     be found. 
     
     IO