Global significance of freshwater swamp forest 
25 
swamp almost thirty years ago (Ng, 1990) and today, the entire world’s population 
of P. reticulata is still confined to the Nee Soon freshwater swamp forest. Hence, 
if Nee Soon freshwater swamp forest were to be lost or modified, this species could 
potentially be rendered globally extinct. 
Conclusions 
Nee Soon freshwater swamp forest constitutes Singapore’s last remaining patch of 
primary freshwater swamp forest. From the viewpoint of species richness alone, this 
makes the conservation of the Nee Soon freshwater swamp forest a top priority. Its 
large number of plant and animal taxa, currently found nowhere else in Singapore, only 
emphasises its conservation value. Finally, given that Nee Soon freshwater swamp 
forest houses a large proportion of Singapore’s overall flora and fauna, conservation of 
this habitat undoubtedly has larger-scale, positive effects for biodiversity conservation 
in Singapore (Ng & Lim, 1992; Turner et al., 1996), accomplishing conservation of 
biodiversity from species to landscape scales. 
Owing to the nature of its ecosystem and drainage, the Nee Soon freshwater 
swamp forest is extremely sensitive to external disturbances (Ng & Lim, 1992). 
Furthermore, many of the species or groups of species found here are rather specialised 
and thus, disturbance of the Nee Soon freshwater swamp forest and its surrounding 
areas would pose a great threat to these unique groups. Therefore, it is important to 
maintain Nee Soon freshwater swamp forest in its current state, as well as ensure 
that it is not affected adversely by development. These are amongst the reasons for 
conducting a long-term research project to intensify knowledge of the freshwater 
swamp forest system (Davison et al., 2018). 
Gaps in research 
Singapore has been gradually building up knowledge on freshwater biodiversity, 
which includes the area in the Nee Soon freshwater swamp forest (Kottelat & Whitten, 
1996; Ng & Lim, 1997). The several biodiversity surveys conducted during the 1990s 
in the nature reserves of Singapore further contributed to this store of information. 
However, the knowledge of wildlife in Singapore is still inconsistent between groups. 
Several surveys have been conducted to record vascular plant species in 
Singapore, including specifically from freshwater swamp forests such as Nee Soon 
(Corner, 1978; Turner et al., 1996). As such, vascular plants are comparatively well 
studied. Among the different groups of plants, angiosperms are by far the most 
extensively studied plant group. Nevertheless, information on diversity of plants is 
probably still incomplete as demonstrated by continuing discoveries in Nee Soon and 
its vicinity (Chong et al., 2018). 
In terms of the understanding of fauna in Singapore, several groups have 
been covered extensively. For example, much is known about the freshwater fish in 
Singapore, and our understanding of this group is among the best in the region (Ng & 
Lim, 1997). The surveys of the 1990s also improved our knowledge of several other 
groups of animals. 
