Distribution, Temporal Change, and Conservation Status of Tropical Seagrass Beds in Southeast Asia: 2000–2020

Seagrass beds consist of marine flowering plants and are one of the most important habitats in the coastal ecosystem of the world. Seagrass beds support numerous flora and fauna, including endangered and commercially important species. They provide many valuable ecosystem services to humans, such as seafood provision, water quality control, disaster resilience, blue carbon stock, disease control, climate regulation, and tourism. The total economic value of seagrass ecosystem services per area exceeds that of terrestrial ecosystems such as forests. Costanza et al. (2014) estimated values of seagrass/algae beds were $28,916 ha−1 year−1, while values of tropical forests were$5,382 ha−1 year−1. Seagrass beds have been threatened by various types of human-induced stressors, including eutrophication, coastal development, and global climate change. Such multiple human-induced impacts cause rapid loss and deterioration of this important coastal habitat. Waycott et al. (2009) estimated that seagrass beds were disappearing at a rate of 7% year−1 globally. However, their data did not contain those from Southeast Asia, where seagrass diversity is the highest in the world (Green and Short, 2003). The estimated global decline of seagrass beds may have been underestimated due to a lack of long-term quantitative scientific data from this region. Thus, it is urgently needed to collect more data and compile already existing data on the distribution of seagrass beds, and to conduct analyses of their recent status and temporal trends for promoting their effective conservation and management.