IJnimpacted stations may be separated on the basis of those with little Chondrus cover in Zone 3 

 ( < 25% on average; group lA) and those with greater Chondrus cover ( > 40%; group IB). These groupings 

 may be further subdivided on the basis of Fucus cover; groups IA2 (FS) and IBl average 30-40% Fucus, 

 groups lAl (SS) and IB2 average about 10%, and group IB3 (BP) with only a trace of Fucus. 



Further subdivisions are based on species complexes unique to each station, and consistent over time. 

 The obvious pattern is for each station to resemble itself more than any other station. Fox Island-Exposed 

 is the only station to show clear changes over time. Collections from FE separate into periods when Fucus 

 was abundant (1979-81), when Fucus was less abundant (and collections were similar to those at Millstone 

 Point, 1982-83), and the period when FE was thermally impacted (1984-85). 



In summary, local rocky intertidal communities, as represented in the undisturbed transects, have 

 undergone drastic changes in the immediate vicinity of MNPS, little change elsewhere. Analyses of data 

 collected during 2-unit operation show that community parameters vary within predictable limits, and that 

 the ob.served patterns of distribution and abundance of intertidal organisms may be explained in terms of, 

 e.g., seasonality, degree of exposure, intertidal height, inter- and intraspecific competition. Similar analyses, 

 using data collected during 3-unit operation, coupled with analyses of individual community components, 

 permit assessment of possible changes to nearby rocky shore communities, especially those that may be 

 affected by the 3-Unit thermal plume. 



Recolonization Studies 



Transects 



Recolonization of denuded areas on local rocky shores is an on-going, naturally occurring process; 

 grazing/predation, storms, senescence, ice/sand scour all clear areas of intertidal rock, and make space 

 available for recolonization. Our recolonization experiments, therefore, allow isolation and identification 

 of some factors that influence the structure of local rocky shore communities. .luvenile stages of 

 recolonization organisms in the denuded transects could be more susceptible to power-plant effects than 

 adults in established populations, and comparisons of rates and patterns of community recovery under the 

 exclusion cages permit determination of the influence of grazing and predation on local intertidal community 

 structure. 



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