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Ganl. Bull. Singapore 70 (Suppl. 1) 2018 
strubelli, Hemiplecta Humphreysiana, Dyakia kintana, Amphidromus atricallosus 
temasek and Amphidromus inversus. There has been no comprehensive information 
on the terrestrial snail and slug species found in Nee Soon freshwater swamp forest, 
even during the last extensive biodiversity survey of the nature reserves conducted in 
1993-1997. Therefore, this study aims to provide baseline information on the biology 
and distribution of terrestrial snails and slugs within Nee Soon. This information will 
be useful in updating the status of individual species and will contribute to the design 
of conservation efforts for the freshwater swamp forest. 
Material and Methods 
Quantitative hand picking sampling was carried out from September 2013 to October 
2015 in 15 plots spread broadly across the Nee Soon catchment in four different 
areas: Upper Swamp (Upper 1 & 2 Sub-catchments), Middle Swamp (Mid 1-3 Sub¬ 
catchments), Lower Swamp (Lower 3 Sub-catchments) and Outskirts (Lower 1 & 2 
Sub-catchments) (Fig.l). The plots were sampled repeatedly for six collection cycles. 
Each plot consisted of two 10 x 5m quadrats. Each quadrat was searched thoroughly 
by two people for half an hour to locate any snails or slugs. Most of the specimens 
were found on the forest floor, hidden within the leaf litter or up on the trees, on 
the underside of leaves. Shell height, width and chirality were recorded at time of 
collection. Shell height was measured from the apex to the lowest part of the outer 
lip parallel to the coiling axis and shell width was measured at the widest part of the 
body whorl perpendicular to the coiling axis. Body length was recorded for slugs. 
Temperature and humidity were also measured at each site and summarised in Table 1. 
The Shannon-Weiner Index (EP) was used to study and compare species diversity 
at each site. The equation for the Shannon-Weiner Index is as follows: 
H’ = -S(Pilog[Pi]), 
where Pi = number of individual species / total number of individuals 
Results 
Family CYCLOPHORIDAE 
Cyclophorus perdix aquila (Sowerby, 1843), Fig. 2A 
Cyclophorus perdix aquila is one of several forest land snail species that survive in 
Singapore’s rainforests. Species from Cyclophoridae require moisture to be secreted 
on the surface of the mantle cavity to aid in respiration, thus most of them are restricted 
to areas that are wet and moist (Tan et al., 2012). All specimens were found near to 
forest streams or swampy areas. 
