Fig. 1.

GBR. (A) High coral cover is typical of the far northern GBR, where disturbances by cyclones and crown-of-thorns starfish are infrequent. (B) Repeated outbreaks by the coral-eating crown-of-thorns seastars have devastated reefs like that shown here. (C) Crown-of-thorns seastars feed on coral. (D) Tropical cyclones are also a major cause of recent coral mortality, as illustrated by a reef seen a few months after it was hit by a category 4 cyclone. (E) Structures provided by reef-building corals are an essential habitat for many of the hundreds of thousands of species associated with coral reefs. (Photographs courtesy of Katharina Fabricius, Australian Institute of Marine Science.)