spring, disappeared in summer, and returned in autumn. At the more 

 exposed stations, Ulothrix , Bangia , and Blidingia were also common in 

 spring and autumn. The Fox Island-Exposed station was unique in having 

 approximately 30 percent each of Fucus and barnacles, and less than 25 

 percent rock; all other stations had a least 45 percent rock and much 

 lower coverage by barnacles and Fucus (Table 1). In general, the develop- 

 mer^ of a high intertidal (Zone I) community was primarily dependent on 

 degree of desiccation, on a seasonal basis and according to degree of 

 exposure; and secondarily, on abundance and distribution of predators 

 and grazers, which also varied seasonally and with exposure. 



Zone II was largely covered by fucoids. In general, Fucus vesiculosus 

 was the dominant alga, but given more protection from surf, Ascophyllum 

 nodosum became more abundant. Bay Point was atypical because of high 

 exposure and concomitant low fucoid coverage; it was dominated by mussels 

 and barnacles. At most stations, barnacle set into Zone II was heavier 

 than that in Zone I and survival was higher (Table 2) . 



Zone III was characterized by high coverage of Chondrus crispus (34 

 percent), and fucoids and ephemerals (approximately 13 percent each). 

 Because Fox Island-Sheltered was subjected to more severe ice scouring, 

 this station differed from the others by having less Chondrus in Zone 

 III (less than 5 percent) , but more Fucus and bare rock (30 and 47 

 percent, respectively). 



The abundances of the perennial algae (e.g., Fucus , Ascophyllum , 

 Chondrus) are not as variable seasonally as those of ephemeral algae or 

 intertidal invertebrates, but changes in percent coverage of these 

 species do occur with time. Coverage can increase as young plants are 

 recruited into the population, or growth and branching of older plants 



14 



