Coral reef benthic composition and its influence on reef fish communities in Buton Islands

Abstract

Benthic communities in coral reef ecosystems are very dynamic and influenced by environmental conditions and human factors. Unfortunately, changes in benthic communities can impact reef fish communities which are essential to support fishery industries. This study investigates the change and relationships between coral reef benthic and fish communities in Buton Islands from 2016 to 2018. The methods used were underwater photo quadrat to estimate percent covers of benthic communities and belt transect to observe the reef fish communities. The result shows that, based on an ordination analysis, the majority of reefs within the years were characterized by Dead Coral with Algae (DCA) and hard coral (HC), indicating that the reef conditions, in general, remained stable during the period. In this case, DCA covers were 42.13 ± 3.66% (SE) in 2016, 42.97 ± 2.21% (SE) in 2017, and 28.46 ± 4.27% (SE) in 2018, whereas, percent covers of hard corals were 28.83 ± 3.92% (SE), 30.16 ± 3.49% (SE) and 35.76 ± 4.41% (SE) for 2016, 2017, and 2018 respectively Although not significantly changing, this stable condition was correlated significantly with overall fish diversity. Furthermore, corallivore species richness and diversity were subject to change when the benthic gradients changed. Although not all fish functional groups were affected (probably due to low percent covers of algae, sponges, soft corals, and others), the change in benthic communities requires more attention, especially when the reefs shift to non-reef building corals-dominated reefs. Continuous monitoring and local communities’ participation need to be improved to maintain the current reef condition and provide better insight regarding coastal ecosystem management.