Figure 5

Hypothesized response of Caribbean coral reef communities to overfishing and sea urchin disease. 

Source: Jackson (1994).

Temperate Zone Rocky Shores

Rocky intertidal zones, and the shallow sublittoral kelp forests just below them, have provided the conceptual framework for research on most other benthic ecosystems (Connell, 1961; Paine, 1980). They therefore offer one of the best possible opportunities for rapid advance in understanding of the dynamics of regional systems.

Many temperate rocky shores have been very extensively altered by the virtual removal of large vertebrate predators such as sea otters (Estes and Palmisano, 1974). Human foraging on intertidal shores and, in more recent decades, recreational tidepool tourism have resulted in some of the more dramatic demonstrations of how direct removal of large numbers of invertebrate and vertebrate carnivores and herbivores, combined with sustained trampling, can locally obliterate the fauna and flora of a rocky shore (Beauchamp and Gowing, 1982; Bally and Griffiths, 1989). Thirty years of visits by hundreds of thousands of school children to the tidepools of what is now a "marine reserve" in central California have resulted in the complete local absence of seashore snails and crabs that are considered to be the most typical representatives of Pacific marine life (R. Breen, pers. comm., 1994). In Chile, the best experimental examples of the devastating effects of human extraction of animals on a marine community come from the rocky intertidal zone (see Box 13).

Rocky shore systems, because of their geographic ubiquity and experimental tractability, remain prototype systems for exploring the connection between biodiversity and ecosystem function. Biodiversity issues at all trophic levels, especially at the microbial level, remain unexplored. The interaction between nearshore oceanography and larval transport is basic to understanding the presence, absence, and distribution of species. This interaction, set against the high



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