the restraining influence of the predator, could monopolize the space 

 or food resources and thus squeeze out less competitive species. For 

 example, the starfish Pisaster ochraceus feeds primarily on mussels. When 

 these starfish are absent, the mussels are the masters of the tidal zone, 

 squeezing out the balanuses and other animals and greatly reducing the 

 species variety (Dayton, 1971; Fotheringham, 1974; Menge, 1972; Paine, 

 1966, 1969a, b, 1974). In exactly the same way, the starfish Pycnopodia 

 hel ianthoides holds down the number of the urchins Strongylocentrotus spp.-- 

 macrophyte feeders (Mauzey and other, 1968). In the opinion of Payne (1966), 

 the local species diversity is directly related to the effectiveness with 

 which predators prevent monopolization of the primary necessary resources by 

 a single dominant species. The number and biomass of such key predators 

 are low--they also have a vulnerable link in their life cycle. This is 

 usually so for the pelagic larvae or fry. In particular, one important 

 limiting aspect in the life of the predator might be the heterogeneous 

 and, consequently, unpredictable for the predator, distribution of the 

 food on which the young animals feed (Birkeland, 1974). 



The formation and existence of climax communities are possible only 

 under stable environmental conditions, in which changes are predictable 

 in terms of period, phase, and amplitude, and do not go beyond the limits 

 of tolerance of the organisms. If the changes are sharp and unpredictable, 

 the climax community is disintegrated or disrupted. The places which are 

 liberated are occupied first by opportunistic species, characterized by 

 rapid reproduction, early maturation, high fertility, short life cycle, 

 high mortality, and simple population structure (Pianka, 1970, 1972). 

 During the course of the succession, they are gradually replaced by more 

 competitive dominant species. In permanently unstable biotopes, a climax 

 is not established and opportunistic species predominate permanently. 

 However, even in stable communities, they may exist, due to aperiodic (and 

 therefore unpredictable) disruptions in the structure of the community, 

 forcibly throwing it into the initial stages of succession. On the land, 

 these disruptions are caused by forest fires, floods and other factors; 

 at sea--by hurricanes, tsunamis, earthquakes, outbursts of predators, etc. 

 Thus, during the past decade on the coral reefs of the Indo-West Pacific 

 area (Great Barrier Reef, Guam, etc.), an unprecedented burst in the 

 development of the "crown-of-thorn" starfish Acanthaster placi has been 

 observed (Chesher, 1969; Pearson, Endean, 1969; and many others). The 

 coral reefs of the Indo-West Pacific are among the most mature and stable 

 of all ecosystems in shallow waters of the world ocean. Acanthaster is 

 usually an extremely rare animal (a few individuals per square kilometer), 

 with old individuals predominating in the population. The mature starfish 

 feed exclusively on hermatypic corals, and the substances excreted as the 

 starfish feed on the coral attract other starfishes. In cases of massive 

 multiplication, this property may lead to the formation of accumulations 

 of many starfish in small areas of reef damage, frequently hundreds of 

 individuals. The starfish attack the coral and destroy it almost completely, 

 and all of the fauna associated with the living coral die. On the surface 

 of the dead coral, algae develop immediately, followed by soft corals, etc. 

 This same succession is observed during restoration of a reef destroyed by 

 an earthquake (D. V. Naumov, personal communication). Complete restoration 



