Despite the apparent randomness, several generalizations may be 

 drawn from the recolonization studies to date. Recovery is more rapid 

 in the low intertidal than in the upper inter tidal, and faster and more 

 complete at exposed stations than at sheltered ones. Predators and 

 grazers have a profound effect on recolonization (Lubchenco 1978) ; they 

 may retard development of some species (e.g., Fucus ) , but they also 

 prevent the monopolization of space by one or a few species (e.g., 

 mussels, Enteromorpha ) . Depending upon time of year, some components of 

 the community (e.g., barnacles, ephemeral algae) may recolonize almost 

 immediately, and others (e.g., Fucus ) recover more slowly (8 mo at an 

 exposed station, up to 30 mo at a sheltered one). Some species (e.g., 

 Chondrus , Ascophyllum ) may require many years to re-establish populations 

 (Prince and Kingsbury 1973; Sundene 1973). 



The slow recovery rates for Chondrus and Ascophyllum in our study 

 are partly an artifact of the experimental design. The method of experi- 

 mental denuding (i.e., scraping and burning) was far more drastic than 

 would be natural removal (e.g., ice-scouring), which would typically 

 remove only the upright thalli, and permit regrowth from the basal or 

 crustose holdfasts. Additionally, the areas denuded were not optimal 

 for the growth of these species; Ascophyllum was not dominant even 

 before the denudation, and Chondrus is more of a subtidal alga, and is 

 usually found intertidally under a fucoid canopy. 



To get a more representative idea of recolonization rates for these 

 species, we propose clearing some areas in established Chondrus and 

 Ascophyllum beds, with denudation to consist of scraping and burning, 

 and scraping only. These experiments should allow us to better determine 

 the ability of. these algae to recover from perturbation. The Ascophyllum 



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