that the rates of loss in Maine and 

 New Hampshire during 1954-74 (and 

 presumably earlier) were much lower 

 than for most of the other Northeast- 

 ern States. 



Marsh vegetation, however, 

 changes in response to many other 

 factors besides those related to 

 human development. For example, 

 Niering and Warren (1980) described 

 shifts that have taken place during 

 the past 25 years on the Wequetequock- 

 Pawcatuck marshes, including a loss of 

 the Juncus belt and a replacement of 

 the S^. pa tens by short S^. alterni- 

 flora . After studying more than 100 

 marshes on Long Island Sound, Niering 

 and Warren felt that while: 



"the Miller and Egler pattern was 

 found to be generally valid ... 

 tidal marsh vegetation is highly 

 dynamic, and our field observa- 

 tions and peat core studies have 

 shown that traditional succes- 

 sional concepts are of limited 



value in terms of interpreting 

 vegetation changes. " 



As a result of their work, they 

 developed a revised version of the 

 often reproduced generalized cross 

 section of the vegetation on a New 

 England salt marsh that was first 

 published by Killer and Egler (1950). 

 The resulting diagram (Figure 17) 

 illustrates the complex distribution 

 that may result from a sequence of 

 changes that Chapman (1940) tried to 

 represent with an involved web of 

 potential vegetation sequences on the 

 New England marshes. After struggling 

 to understand salt-marsh succession, 

 Chapman commented with understatement: 



"This scheme may appear somewhat 

 bewildering as it is very com- 

 plex, but the present author has 

 been forced to the conclusion 

 that salt marsh succession is by 

 no means the simple phenomenon 

 seen by earlier authors, and 

 that it can only be represented 



UPPER BORDER 



Pa 



HIGH MARSH 



LOW MARSH 



/ Jg/Ds 

 Jg Ds 



Sp 

 Sp/Ds If 



Forbs 



'nHm\UNim^iV^4Vlll^!f tl,f^^^^[j^^^^Sas 



DITCH 



PANNE 



DITCH 



Figure 17. Generalized transect from the uplands to the low intertidal in a 

 "typical" New England salt marsh showing the common vegetation types. Key to 

 symbols: Sat = tall Spartina alterniflora ; Sp = Spartina patens ; Ds = 

 Distichlis spicata ; Sas = short Spartina alterniflora ; If = Iva frutescens ; 

 Jg = Juncu s gerardi ; Pv = Panicum virgatum ; Pa = Phragmites austral is . From 

 Niering and Warren (1980). 



27 



