ABSTRACT
Habitat degradation has detrimental effects on ecological assemblages, and on coral reefs it is manifest as declines in the cover of habitat forming scleractinian corals. The causes of coral reef degradation are many and vary geographically. These impacts are very concerning as millions of people rely on coral reefs for food and livelihoods, and chronic habitat degradation is threatening goods and services provided by these systems. Parrotfishes are a conspicuous and important component of coral reef fish faunas that are considered fundamental to the resilience and functioning of coral reefs. However, there are conflicting reports about the vulnerability of the group to the chronic degradation of coral reefs. This chapter explores species specific differences in the vulnerability of parrotfishes to different disturbances by firstly compiling published data on the changes in parrotfish abundance during disturbances that have caused coral loss. This is then complemented with new data from long-term and spatially extensive surveys across the Great Barrier Reef to explicitly examine responses of parrotfishes to temporally and spatially discrete disturbance events. Parrotfishes are generally resilient to coral depletion and habitat degradation caused by major disturbances affecting contemporary reef environments (e.g., cyclones, coral bleaching, and outbreaks of crown-of-thorns starfish), though parrotfishes (like most reef fishes) are sensitive to widespread or significant loss of topographic complexity, which may occur due to extensive coral loss. Currently however, the major threat to parrotfishes is fisheries exploitation, which is of considerable concern given their importance to coral reef resilience.
