PREFACE 



Submarine forests of giant kelp 

 ( Macrocystis ) , with plants over 50 m tall 

 growing from the bottom to the surface of 

 the sea, probably intrigued humans long 

 before the first published insights into 

 their ecology by Darwin in 1860. Even 

 with only a limited view from the surface 

 and observations from collections, Darwin 

 was clearly fascinated by giant kelp and 

 the diverse organisms associated with it, 

 and made the first analogy between this 

 community and terrestrial forests. Except 

 for a few subsequent reports on the extent 

 of the Macrocystis resource in California, 

 it was almost a hundred years after 

 observations in South America 

 study of California kelp forests 

 Andrews' (1945) 

 on the fauna of 

 included some 



Darwin's 

 that the 

 began, 

 research 

 holdfasts 



pioneering 



giant kelp 



underwater 



observations, but this and other early 

 studies were hampered by the lack of 

 simple diving equipment. With the advent 

 of SCUBA in the early 1950's, direct 

 observations of kelp forests became 

 relatively simple and, because of mounting 

 concern over the effects of sewage 

 discharges, loss of kelp habitat, and 

 possible impacts of kelp harvesting, a 

 number of kelp research programs were 

 Thus, giant kelp communities 

 examined in detail for only 

 more than 30 years. The 

 of this profile are to review 

 what is known about kelp 

 emphasis on Macrocystis 



started, 

 have been 

 si ightly 

 objectives 

 and summarize 

 forests, with 



pyrifera communities in California, and to 

 suggest future research needs and 

 approaches necessary to improve our 

 understanding of the ecology of these 

 complex communities. 



Cowardin et al . (1979) classified 

 these habitats as occurring in the 

 Californian Province, marine system, 

 subtidal subsystem, aquatic bed class, 



algal bed subclass, and Macrocystis 

 dominance type. Although we recognize the 

 need for such a classification system, 

 much of the recent work on kelp 

 communities emphasizes their considerable 

 natural variation. Thus, within a 

 particular forest there may be areas of 

 rock bottom class and unconsolidated class 

 with most associated subclasses (bedrock, 

 rubble, cobble-gravel, sand) and with 

 various dominance types ( Laminaria , 

 Pterygophora , various red algae, various 

 invertebrates); the classification of a 

 particular area may change with time. The 

 modifiers used by Cowardin et al. (1979) 

 are less variable in kelp forests; the 

 water regime is almost always subtidal, 

 and the water chemistry is euhaline. We 

 have restricted our detailed review to M. 

 pyrifera forests in California (including 

 the Pacific coast of Baje California, 

 Mexico) because this section of coastline 

 includes the entire geographic range of 

 the plant in the northern hemisphere (see 

 Chapter 1), because the environment within 

 this range is more similar than between it 

 and other geographic areas, and because 

 most research has been done here. In 

 addition, the majority of the profile is 

 devoted to Macrocystis itself because we 

 know more about it than other species in 

 the community, because it defines the 

 subject of the profile, and because our 

 own work has focused on it and associated 

 plants. 



To accomplish the above objectives, 

 we have attempted to review most of the 

 available literature on California kelp 

 forests, and to compare and contrast this 

 information with relevant studies on kelp 

 forests and beds in other areas. Most of 

 the early work on Macrocystis in 

 California is reviewed in North TT971a). 

 We acknowledge the pioneering work of 

 Wheeler J. North, and have relied heavily 



in 



