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the absence of Macrobrachium idae, M. neglectum and Caridina gracdirostris implies 
that these species may have been extirpated from Nee Soon freshwater swamp forest. 
All three species need brackish waters to complete the development of their larvae. It 
is likely that the dam built to construct the Lower Seletar Reservoir in 1986 prevented 
the downstream breeding migrations of these three species and rendered them unable 
to complete their life cycles (Cai et al., 2016). The Green Tree Snail, Amphidromus 
atricallosus temasek was listed as “Endangered” in the Singapore Red Data Book and 
was found to have a widespread population in Nee Soon freshwater swamp forest being 
recorded at eleven sites, although its mean abundance was low. Other rare species may 
deserve a national conservation status of Endangered or Vulnerable such as Cyclotus 
rostellatus, Japonia ciliocinctum and Microparmarion strubelli. All were extremely 
restricted in their distribution and exist only within a few isolated patches of Nee Soon 
freshwater swamp forest. 
Recommendations 
In view of these results in the context of existing scientific knowledge, specific 
recommendations for i) long-term monitoring, ii) future research, and iii) management 
options to ensure continued protection of the aquatic fauna of the Nee Soon freshwater 
swamp forest are as follows: 
i) Future monitoring 
Long term monitoring and sampling of faunal populations are needed to build on 
current knowledge and capture long-term trends. This is to optimise the value of the 
knowledge/data of Nee Soon freshwater swamp forest faunal communities gained 
from this study. Ecological and water quality monitoring at the downstream “edge 
habitat” sites in association with similar monitoring of (and access to physicochemical 
data from) the spillway itself as well as in Upper Seletar Reservoir (close to the 
spillway outlet) and access will be particularly valuable to assess the medium- to 
long-term effect of the spillway transfer on the Nee Soon freshwater swamp forest 
faunal communities and/or the stability (e.g. resistance, resilience, adaptation) of these 
communities to disturbance. A spatially localised project of this nature (of at least 2 
year duration to capture temporal and seasonal patterns) is highly feasible, and would 
help to answer important questions pertaining to the spillway and its effects on Nee 
Soon freshwater swamp forest. 
Adoption of standardised survey techniques, such as those applied here for faunal 
as well as habitat and other abiotic factors will enable comparison of long-term changes 
as well as spatial comparisons within the forest catchments but also against locations 
elsewhere in the context of a national monitoring programme. Ecological monitoring 
programmes for inland waters including aspects of these techniques are in various 
stages of application across Singapore, supported by NParks and PUB (e.g. Clews 
et al., 2012, 2014; Blakely et al., 2014; http://emid.nus.edu.sg/Inland/ecostandards. 
jsp) in line with programmes developed internationally (e.g. Barbour et al., 1999; 
ANZECC 2000a, 2000b; CEC, 2000). Ideally, at least annual screening for surveillance 
monitoring should be conducted at multiple stations (preferably representing a range 
