GROWTH AND ECOLOGY OF Spartina alterniflora 



427 



Biomass 



The increase in biomass of Spartina in Maine follows an 

 exponential growth curve that usually peaks in August. Biomass 

 estimates at Causeway Marsh for 1972 to 1974 averaged 1.04 kg/m'^ 

 for July and August (Vadas et al., 1976). Average biomass values for 

 July and August 1975 to 1977 decHned by 42% over the average of 

 the previous three summers. These changes resulted from natural 

 variability (Vadas et al., 1976) and likely from physical changes 

 (especially sEilinity) in Montsweag Bay. Negative correlations between 

 biomass and salinity were observed for other marsh grasses, e.g., S. 

 alterniflora (Adams, 1963) and S. foliose (Phleger, 1971). However, 



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1976 



CAUSEWAY MARSH 



Fig. 4 Monthly size distributions for Spartina alterniflora at Cause- 

 way Marsh (control) (1976 only) and at Bailey Marsh (stressed) during 

 the last full year of surface discharge (1974) and after diversion of 

 effluent through the diffuser (197 5—1977). 



(Figure continues on following page.) 



