Lee Kong Chian Natural History Museum

Freshwater Swamp

Photo credit: Wang Luan Keng

Description

Freshwater swamp habitats occur in the flooded riparian zones of slower flowing stretches of forest streams. The only substantial freshwater swamp and the last ecosystem of its kind in Singapore is found in the Nee Soon Swamp Forest, which houses a small remnant of the original freshwater swamp. It is left in its pristine state due to it being confined in the firing buffer zone where human access is restricted by the Ministry of Defence.

The low-lying swamp is formed where slow-flowing streams drain into shallow valleys. Its water is clear but stained with dark-tea colour due to tannins leeching out from decomposing plant matter accumulated in the swamp. Thus, the pH of the water is more acidic (pH 5.5) than usual forest streams. The swamp is flooded periodically or semi-permanently, resulting in waterlogged soils that are anaerobic and unstable. All these factors form a unique habitat supporting a high diversity of flora and fauna that are adapted to this surrounding. Up to 700 species of vascular plants were recorded in this habitat whereas about 16% of the total fauna in Singapore ranging from freshwater arthropods to amphibians and fishes are mainly, if not exclusively, found in this small habitat. This includes 18 freshwater fishes, two frogs, two snakes, five lizards, two turtles, five prawns and three crabs. Among these, the swamp freshwater crab (Parathelphusa reticulata) is endemic to Singapore and found nowhere else in the world, making it potentially one of the most endangered species on Earth.

Freshwater swamps are extremely sensitive to disturbances due to the nature of this ecosystem and its drainage. It is threatened by changes in drainage regime, soil erosion, development and also introduction of exotic species.

Keywords

Freshwater Swamp

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