24 
Ganl. Bull. Singapore 70 (Suppl. 1) 2018 
of a dryland forest (Corner, 1978). In addition, Corner (1978) noted that the vegetation 
of the Mandai Swamp Forest, of which the Nee Soon freshwater swamp forest is the 
largest surviving remnant, was intermediate between a freshwater swamp forest and 
a peat swamp forest. Corner (1978) further suggested that patches of substrate that 
contain peat mats and decaying organic matter may transition to a full peat swamp 
forest at some point in the future (Ng & Lim, 1992). 
Studies are lacking on the aquatic flora of the Nee Soon freshwater swamp 
forest; nevertheless, the investigations of Lok et al. (2009) documented the occurrence 
of the locally rare forest water lily, which they called Barclaya kunstleri Ridl. 
(Nymphaeaceae) but which is treated as a synonym of Barclaya motleyi Hook.f. by 
Kiew (2015). This was noted as occurring within the forest at least until 1954 but now 
it appears to be extinct at Nee Soon and only present in Singapore at Bukit Timah. 
Aquatic fauna structure of Nee Soon freshwater swamp forest 
The fauna of the Nee Soon freshwater swamp forest is rich and highly diverse. Insects 
and birds make up the largest proportion of animals, whilst molluscs and annelids 
make up a total of 3% of the species documented from Nee Soon. Additionally, Ng & 
Lim (1992) and Yeo & Lim (2011) have documented that 71% of the amphibians, 28% 
of the reptiles, 47% of freshwater prawn and 57% of freshwater crab species known 
in Singapore still exist in the Nee Soon freshwater swamp forest. The forest also 
contains the highest proportion of threatened native freshwater fish and crustaceans in 
Singapore (Ng, 1997; Ng & Lim, 1997). 
It is also the only area in Singapore where 11 out of 26 known species of native 
freshwater fish can be found, including species such as the dwarf snalcehead ( Channa 
gachua ), which was thought to be extinct in Singapore for 20 years before being 
rediscovered in 1989 (Ng & Lim, 1989), as well as the black snakehead ( Channa 
melasoma ), which was first recorded from Singapore only in 1990 (Ng & Lim, 1990). 
Some other fish species in the Nee Soon freshwater swamp forest that cannot be found 
elsewhere in Singapore include the spotted eel-loach (. Pangio muraeniformis ) and the 
grey-banded loach (. Nemacheilus selangoricus ), while many other fish species known 
from the Nee Soon freshwater swamp forest are also forest specialists that are only 
found within such habitats. 
The Nee Soon freshwater swamp forest is also a vital area for conservation of 
freshwater invertebrates (Ng & Lim, 1992) in Singapore, as it was found to have the 
highest diversity of water beetles in the country (Balke et al., 1997), whilst odonate 
diversity was also found to be very high with eight species being exclusively found 
in the Nee Soon freshwater swamp forest (Murphy, 1997). Additionally, the forest 
also has the highest diversity of semi-aquatic bugs (Gerromorpha) in Singapore, with 
83% of Singapore’s Gerromorpha species having been recorded in the swamp forest 
(Yang et al., 1997). The forest is also a stronghold for freshwater decapods, with 
multiple species of freshwater shrimp, such as Macrobrachium platycheles (which 
was originally described from the area), having thriving populations there. Perhaps 
the most important decapod found within the Nee Soon freshwater swamp forest is 
the endemic swamp forest crab, Parathelphusa reticulata. It was described from the 
