Distribution and significance of seagrass ecosystems in Malaysia

Seagrasses are the only flowering plants (monocotyledonous Angiosperms) that have adapted themselves to living in marine and estuarine habitats, and are submerged most of the time. They are rooted in sediments on the sea bottom, with shoots appearing above the substrate. Seagrasses occurred at 78 sites scattered in the west and east coasts of Peninsular Malaysia and in Sabah and Sarawak in East Malaysia. They are usually found along the coasts growing in association with shallow inter-tidal, mangroves, coral reefs, semi-enclosed lagoons and shoals. In these habitats, seagrass beds or meadows have distinct species assemblage completely adapted to the submerged life. There are fourteen major species of seagrasses recorded in Malaysia: Enhalus acoroides, Halophila beccarii, H. decipiens, H. ovalis, H. minor, H. spinulosa, Halodule pinifolia, H. uninervis, Cymodocea rotundata, C. serrulata, Thalassia hemprichii, Syringodium isoetifolium, Ruppia maritima and Thalassodendron ciliatum. Although seagrasses make up only a small portion of the marine ecosystem, the physical settings and their interactive community within and from outside account for their high diversity and ensure survival of an assortment of vertebrates (fish), invertebrates (shrimps, starfish, sea cucumbers, bivalves, gastropods), and seaweeds. Seagrass form the food and habitats for the vulnerable dugongs or sea cows (Dugong dugon), seahorses (Hippocampus spp.) and endangered green turtles (Chelonia mydas), and for other fish, and also a feeding ground for seasonal migratory birds, Egretta garzetta. Seagrasses provide conditions for the growth and abundance of invertebrates and fish that many local coastal communities collect and catch for their livelihood. Seagrass ecosystems are sources of food and yet they are continually threatened by human activities, causing their degradation and possible habitat loss. The purpose of this review is to give information on the significant linkages of seagrasses with the coastal inhabitants and to suggest recommendations for the protection and conservation of this important ecosystem and the associated resources.