production. In Maine, cordgrass and salt hay dominate the emergent salt marsh 

 flora. Research in Maine salt marshes has concentrated on characterizing the 

 intertidal emergent cordgrass community. 



Causeway Marsh, a cordgrass marsh in Montsweag Bay, was studied in detail over 

 a 5-year period by Vadas et al. (1976) and Keser et al. (1978). Linthurst 

 (1977) made a comprehensive study of Maine salt marsh productivity in Franklin 

 and Salisbury Cove near Ellsworth, Maine. McGovern (1978) looked at above- 

 and below-ground biomass, net productivity, elemental composition, and 

 elemental release of cordgrass at Herrick Bay near Brooklin, Maine. The 

 following is based largely on their work. 



In Maine, cordgrass shows two distinct peaks of plant density (figure 5-46) 

 during the growing season (Vadas et al. 1976; and Keser et al. 1978). A high 

 density appears in spring when young plants first appear. In late spring and 

 early summer, densities decrease as intraspecif ic competition for light, 

 nutrients, and space increases (Vadas et al. 1976). In late August or 

 September an increase in density is produced by a new crop of small plants 

 from tillers and rhizomes of mature plants. At Causeway Marsh stem densities 

 per square meter in late summer ranged from 1676 in 1972 to 1306 in 1974. 

 Spring densities were 1541 in 1972 and 2035 in 1974. 



Linthurst (1977) reported the following stem densities for three dominant 

 species of salt marsh emergent vegetation in Maine salt marshes: 



Stem densities for salt hay in Maine are far higher than those in Delaware 

 (5900 ±574) or Georgia (2900 ±484; Linthurst 1977). Shoot densities for 

 cordgrass not growing on creek banks are remarkably similar (Linthurst 1977; 

 and Vadas et al. 1976). 



In June, the new spring growth of cordgrass is approximately 8 to 24 inches 

 (20 to 60 cm) high. Most plants are tallest (7 feet; 2 m) in July. By August 

 a second growth of small plants begins. The second crop rarely grows higher 

 than 1 foot (30 cm; figure 5-46; Vadas et al. 1976). 



Vadas and coworkers (1976) observed that cordgrass plants over 3 feet (1 m) 

 tall usually begin to flower in August. A maximum net estimate of biomass 

 (peak standing crop) was 1419 g dry wt/m^ in 1974 at Causeway Marsh, according 

 to Vadas et al. (1976). Maximum biomass usually occurs between July and 

 September and often is followed by a decrease of 40% to 50% within a month 

 after the maximum biomass is attained (Vadas et al. 1976). The maximum living 

 and dead biomass of cordgrass in the Franklin and Salisbury Cove area is 863 ± 

 140 g dry wt/m for creek bank cordgrass (Linthurst 1977). The biomass of 

 cordgrass near Herrick Bay peaked at 508 g dry wt/m ^ (McGovern 1978). 



5-122 



