Benthic structure drives butterflyfish species composition and trophic group abundance

Corals provide structure and food sources vital for the maintenance of coral reef fish diversity. However, coral reefs are currently under threat from climate change, which has led to the largest recorded loss of live coral. The loss of live coral, and corresponding shift in reef benthic composition, are predicted to impact the abundance and composition of coral reef fish species and communities. In this study, we investigate the effect of changes in reef benthic composition (eg. live coral, dead coral, algae), on the diversity and composition in an assemblage of butterflyfish species, in Faafu Atoll in the Maldives after the 2016 bleaching event. We show that differences in community composition of butterflyfish are associated to benthic structure, reflecting species feeding preferences. Interestingly, however, we also show that lower coral cover is not associated to lower abundance and species richness of butterflyfish. Our results suggest that maintenance of coral reef structure after a disturbance provides key microhabitats to accommodate non-corallivorous butterflyfish, thus maintaining abundance and species richness. Overall our study provides support for regulation of richness and abundance of coral reef fish assemblages to short term changes in coral reef benthic composition after disturbance via turnover in composition.