Assessing of coral reef resilience on Lembeh Island, North Sulawesi

Abstract

Resilience is the ability of a system to reach equilibrium after a temporary disturbance. When an ecosystem is disturbed, then the recovery of the system is very dependent on the diversity of species that are still left. The remaining communities determine the direction of new successional communities formed after the disturbance has passed, including coral, fish, and other biota communities. This study aimed to determine the level of resilience of coral reef ecosystems on Lembeh Island. The observation was carried out from January 16-19, 2019, at a 7-meter depth. Determination of the coral reef index will refer to coral reef resilience index table. It is found that the resilience of coral reefs on Lembeh Island currently has a high potential for recovery (resilience) from natural stressors based on the 16 parameters. Seven parameters have very high resilience values: the proportion of bleaching resistant species, community resistance to bleaching, taxonomic diversity, size/age distribution, the abundance of reef fish on live coral, and the abundance of coral benthos on live coral and coral disease levels. Lembeh Island is dominated by hard corals measuring between 5.1 to 25 cm (size M) by ~46%, then sizes more than 25 cm (size L) by ~37% and juvenile size (size S) by 17%. The coral health index on Lembeh Island has the capacity to recover if the condition of coral cover is minimally maintained or improved and lower fleshy seaweed cover by increasing the abundance and biomass of herbivorous fish.