Reef-scale variability in fish and coral assemblages on the central Great Barrier Reef

Coral reefs are threatened by changing climatic conditions, which will potentially alter the frequency and severity of disturbances in coming decades, casting doubt over the potential for reefs to recover and re-assemble the structure of their fish and coral assemblages. Here, fish and coral assemblages were examined at four reefs similar in size, aspect, disturbance history and latitudinal position from 2006 to 2016. We quantified variation in species and functional level assemblage structure among reefs before and after disturbance and examined whether there was evidence of any recovery. Fish and benthic assemblages varied in density and diversity, but the proportion of fish functional groups was similar among reefs. While some post-disturbance recovery of the benthos was evident, changes in fish functional structure did not uniformly reflect benthic recovery patterns. The apparent disconnect between changes in fish community structure and coral recovery may be due to lagged responses of some fishes post-disturbance, lack of reliance on hard coral cover by some fish trophic groups, or retention of habitat complexity. These results highlight the importance of reef-scale data in determining capacity of coral reefs to recover from disturbance.