Coral Recruitment Potential on Singapore’s Urban Reefs
摘要
The successful recruitment of coral juveniles to reefs damaged or degraded by disturbance events is a key mechanism of reef recovery and resilience. Coral larvae and newly settled corals are particularly sensitive to external influences, and environmental conditions during critical post-settlement periods play a crucial role in driving recruitment rates. Coral reef communities in Singapore persist in a highly sedimented, urban environment subjected to frequent and multiple anthropogenic and climate change-related disturbances. Here we examined the spatio-temporal patterns of coral recruitment on Singapore’s reefs. Recruitment of coral spat observed in this chapter was influenced by density and diversity of the adult coral population in the vicinity, competitive interactions with other benthic species, climate and water conditions. Overall mean recruitment rate of 167.4 ± 8.6 spat m−2 y−1 was generally higher than previously reported for Singapore’s reefs. Highest numbers of recruits were observed at Pulau Satumu, which also had the highest coral cover and diversity of the three reefs examined in this study, and lowest number of recruits was observed at Pulau Hantu. Only small numbers of juvenile colonies have been observed over the years, possibly indicating high post-recruitment mortality caused by suboptimal environmental conditions. From the 15-year ecological monitoring dataset, it was apparent that climate change-induced warming of seawater played a significant role in depressing coral recruitment in Singapore. However, there is a possibility of reef replenishment for as long as the corals continue to produce viable larvae.