April 2003
Biodiversity and resilience of coral reefs With over 3000 fish species, Indo-Pacific coral reefs represent one of the most diverse ecosystems on the globe. It is easy to assume that the loss of one or two species from these systems would have little impact. However, in an article in the April issue of Ecology Letters, Bellwood and colleagues document major changes in Indo-Pacific coral reef ecosystems as a result of over-fishing just one species, the giant humphead parrotfish.As each parrotfish consumes over 5 tonnes of reef carbonate per year, this species represents a major bioeroding agent on reefs. On unexploited reefs this bioerosion balances reef growth. This species, however, is highly vulnerable to spearfishing. The researchers found that human activity was negatively correlated with fish bioerosion rates, regardless of local fish biodiversity. High biodiversity does not ensure ecosystem resilience. The loss of just one species may markedly change the nature of coral reef ecosystems. | |