Disturbance and the structure of coral reef fish communities on the reef slope

Three levels of physical disturbance were applied to corals in permanent 10 x10 m quadrats along a section of fringing reef at Lizard Island on the Gre at Barrier Reef to investigate the response of fish assemblages. Tabular an d corymbose corals were overturned and left in situ, reducing total hard co ral cover from similar to 55% to similar to 47%, similar to 43%, and simila r to 34%. Despite pre-existing associations with benthic cover, all fish gr oups examined (pomacentrids, labrids, chaetodontids, and acanthurids) were resistent to benthic disturbances at the level and scale at which they were applied. Partial Mantel's tests, in combination with partial Canonical Cor respondence Analysis enabled spatial and temporal variation to be factored out from experimental effects. Most of the variation in the fish community could be assigned to spatio-temporal variables, indicating that spatial str ucture over the reef landscape may moderate localised disturbance effects. This study indicates that coral reef fish assemblages may be more resistant to disturbance than many correlative studies would suggest, and highlights a need for further information on levels and scales of natural habitat dis turbance in order to apply a structured approach to the experimental invest igation of the importance of habitat in structuring coral-reef fish assembl ages. (C) 1998 Elsevier Science B.V. All rights reserved.