Evolutionary Paleoecology of Caribbean Coral Reefs

Aronson, Richard; Precht, William

Ecologists have radically altered their thinking about coral reefs, and those views continue to evolve. Coral reefs, formerly viewed as stable, equilibrial systems (Newell 1971), are now interpreted as nonequilibrial on ecologically relevant scales of time (years to decades) and space (landscapes to reef systems) (Grigg and Dollar 1990; Karlson and Hurd 1993; Edmunds and Bruno 1996; Brown 1997). Increasing awareness of this variability is motivating a strategic shift in coral reef research. Paleontologists are , taking up the quest for predictability, searching for large-scale patterns in the fossil record (Jackson, Budd, and Pandolfi 1996). The nonequilibrial view of reef ecology gained initial support when the intermediate disturbance hypothesis was formulated for coral reefs in the 1970s (Grassle 1973; Connell 1978). This hypothesis predicts maximum diversity at intermediate levels of disturbance. At low disturbance levels the competitive dominants exclude other species, whereas at high disturbance levels good colonizers, which are poor competitors, are the only ones able to persist. Intermediate disturbance levels strike a balance between the slowly recruiting competitive dominants and the rapidly recruiting competitive subordinates, leading to coexistence and higher diversity than at the extremes of the disturbance continuum. In 1980, Hurricane Allen further promoted the idea of nonequilibrium on coral reefs by devastating the best-studied reef in the Caribbean: Discovery Bay, on the north coast ofJamaica (Woodley et al. 1981). Attempts to fit the effects of Hurricane Allen into an intermediate disturbance scenario of increasing coral diversity (Porter et al. 1981) helped convince many ecologists that hurricanes are an important structuring force in coral reef communities. ... Many coral reefs worldwide have changed dramatically since the 1970s. Coral cover has typically declined, and the cover of noncoralline, fleshy and filamentous macroalgae (henceforth "macroalgae") has increased (Done 1992a; Wilkinson 1993; Ginsburg 1994; Cortes 1997). This transition has been particularly pronounced in the Caribbean region, including the Florida Keys and the Bahamas (Rogers 1985; Porter and Meier 1992; Ginsburg 1994; Hughes 1994; Connell1997).

Evolutionary Paleoecology of Caribbean Coral Reefs

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