Freshwater decapod crustaceans serve important ecological functions in tropical stream ecosystems. Stream surveys for decapod crustacean fauna were conducted between February 2015 and April 2016 at nine sites in Bukit Timah Nature Reserve (BTNR). A total of eight species (four freshwater crab, three freshwater shrimp and one crayfish species) out of the nine species known from BTNR were recorded. In general, the species were recorded from sites matching environmental conditions previously known or reported for each species, with some crab species showing minor overlap in their spatial distributions. This highlights the importance of broad-based conservation efforts focusing on the entire stream network in BTNR rather than on specific/selected streams as the various species each appear to have largely unique habitat requirements. The updated information on freshwater decapod crustaceans in BTNR can be used to inform the formulation of conservation and management measures including the establishment of monitoring programs for the protection of our native and threatened aquatic fauna in BTNR.

Bukit Timah Nature Reserve (BTNR) holds the largest remnant patch of primary rainforest in Singapore and its hill streams supports many native and threatened freshwater fauna. As the last comprehensive survey of freshwater fishes in BTNR was published nearly two decades ago, a series of surveys was carried out at 12 streams permeating BTNR and the Singapore Quarry to update the status of the fishes. Of the 27 species documented, 16 are native to Singapore and 11 are introduced. Two native species known from other parts of the Central Catchment Nature Reserve are recorded for the first time in BTNR. Species distribution, richness and abundance have been qualitatively assessed in relation to habitat characteristics. Potential threats and mitigation measures are discussed, which are important in the formulation of conservation and management strategies to safeguard the current diversity of freshwater fishes, many of which are threatened in rapidly developing Singapore.

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