Executive summary 



The past and present-day distribution of eelgrass (Zostera marina 

 L.) in Buzzards Bay was documented using aerial photographs, field 

 surveys, nautical charts, sediment cores, and first-hand accounts. 

 Today, eelgrass is a dominant habitat along the shallow margins of 

 Buzzards Bay. Eelgrass growth correlates with local temperature and 



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insolation, and annual production is -350 g C m ^ y . In Buzzards Bay, 

 eelgrass covers 41 km^ of substrate and accounts for 11% of primary 

 production; in small shallow bays, eelgrass beds account for 40% of all 

 production. Equally important, these beds act as a nursery, refuge, and 

 feeding ground for many fish, invertebrates, and waterfowl. 



A "wasting disease" destroyed virtually all eelgrass in Buzzards 

 Bay (and elsewhere in North America) during 1931-32. All documentation 

 suggests that eelgrass populations equaled or exceeded present-day 

 abundance prior to this catastrophe. Photographs taken 6 to 10 years 

 after the disease show that eelgrass covered less than 10% of the 

 present-day habitat area in Buzzards Bay, and many areas were not 

 recolonized for decades. 



The process of recolonization was similar in many areas: new beds 

 initially appeared on bare substrates, beds expanded, additional new 

 beds appeared, and some beds were removed by disturbance. In this way 

 eelgrass population saturated small areas (1-10 ha) 5 to 15 years after 

 initial colonization. Rates of eelgrass colonization over larger 

 regions (100 's of ha) depended on distance from refuge populations and 

 heterogeneities of the environment. The greatest rates of eelgrass 



