Occurrence and Distribution of Primary Freshwater Molluscs in Singapore

Freshwater molluscs are important components of the fauna of Singapore. However, a perusal of local literature has shown a paucity of information on these animals. A survey was conducted to investigate the occurrence and distribution of the primary (non-brackish) freshwater molluscs of Singapore. Six different types of habitats were sampled from around the island. Four localities were chosen to represent each habitat type, giving a total of 24 localities. A total of 21 species of primary freshwater molluscs were collected, of which 12 were new records for Singapore. The information on the distribution and ecology of each species were provided in this paper. The means for molluscan species richness, abundance, diversity indices, pH and hardness of each habitat type were also calculated and compared. The results of this study showed significant differences in molluscan species richness and abundance among the six habitats. Molluscan species richness was only slightly correlated with pH, but was significantly correlated with hardness across the habitats. Molluscan abundance was significantly correlated with pH and hardness across the habitats.