Marine habitats and biodiversity of Singapore's coastal waters: a review

Rapid and sustained coastal development, land reclamation, and intense use of surrounding waters by shipping, have changed the original land- and seascape of Singapore in the last two centuries. Reclaimed land now account for more than 30% of the current land area, with a concomitant loss of original intertidal and subtidal habitats across most of the southern shoreline of Singapore mainland as well as other offshore islands. The extent of coral reefs, mangroves, mudflats, seagrass beds, estuarine reefs, sandy and rocky shores has diminished considerably, so much so that man-made habitats such as seawalls, tidal canals, swimming lagoons and other artificial structures now form significant marine habitats in their own right. These remarkable changes in the marine environment have affected marine organisms to a greater or lesser extent, based on the very limited information available on marine habitats in Singapore prior to large-scale reclamation. However, the present extent and diversity of marine life that can be observed in Singapore today is still impressive. Much remains to be discovered and deciphered in terms of their biology and ecology. New records and species new to science continue to be described, even as new coastlines are built, and organisms continually adapt to a changing environment characterized by chronic disturbance. This review serves as a snapshot of the current state of knowledge of marine habitats and biodiversity in Singapore based on existing literature. Key threats and knowledge gaps are also highlighted.