Utilizing the Autonomous Reef Monitoring Structure (ARMS) to study the temporal variation of benthic community on coral reef ecosystems in Pemuteran, Bali, Indonesia

Tracking changes in community composition in the coral reef ecosystem is essential, mainly to understand the complexities of the ecosystem and its long-term response to environmental and anthropogenic threats. A standardized method sensitive to changes and comparable across sites is needed to provide robust data helpfully. We used a standardized monitoring protocol Autonomous Reef Monitoring Structure (ARMS), to investigate the growth of marine sessile communities and observe variations in motile taxa (decapods) composition through time. Eighteen units of ARMS were deployed at a depth of ∼10–15 m in the coral reef ecosystem in Pemuteran, Bali, Indonesia; three units were then recovered every two months for one year. The sessile community in each ARMS plate was then photographed and annotated using a web-based annotation tool called CoralNet, while the motile decapods were identified using their morphological characteristics. We observed twenty-four benthic categories of sessile communities and three infraorder of decapods across the sampling duration. The sessile community was contributed mainly by Encrusting Sponge, Brown Flesh Algae, and Bryozoan in almost every sampling duration. The ANOVA result shows that the composition is significantly different over time, showing apparent changes in composition. However, the NMDS result indicated similar structure composition during the ARMS’s time retrieval. Future research on temporal changes in benthic diversity can be used to understand the dynamic more about relationship between motile and sessile and how their interaction can affect the coral reef community.