Greening of Eco-Link @ BKE

Greening of Eco-Link @ BKE
A Safe Passage for Wildlife


The completed Eco Link spanning across the BKE

Way back in 1986, when the roads engineers of the then Public Works Department designed the Bukit Timah Expressway (or BKE as we acronym-mad Singaporeans know it by), their emphasis was to create an efficient transport link from the Causeway to downtown Singapore. Back then, probably the most efficient route took the expressway right through the Central Catchment, splitting the Bukit Timah Nature Reserve from the rest of the Central Catchment Nature Reserve.

Elbowed Pierrot (Caleta elna elvira) one of the species observed 

Over the decades that passed, nature observers lamented the fragmentation of the two major high biodiversity nature areas by the BKE. Animals separated by the BKE remained on the two sides and were unable to cross the expressway without the risk of being killed by vehicles. The expressway became an insurmountable barrier.

Lesser Harlequin (Laxita thuisto thuisto)

In 2005, the nature community and the government authorities mooted the idea of a nature or green corridor to re-connect BTNR to the CCNR. After some debate and feasibility studies, the location selected for this biodiversity-bridge was confirmed. It took some time for the realisation of this Eco-Link as there were issues like design, budget, effectiveness and environmental impact of the link to be dealt with.

After further delays, the contract was finally awarded to local contractor Eng Lee Engineering for a contract sum of $11.8M. The Ground Breaking Ceremony for the Eco Link was held on 30 Jul 2011. Today, slightly over two years after work commenced on the Eco Link, I attended the Greening of the completed Eco Link.


Group Photo at the Tree Planting site (via Twitter by ©Debby Ng)

This was basically an event to celebrate the completion of the biodiversity link with a tree-planting ceremony involving the nature community. The event was graced by the Minister of State for National Development, Mr Desmond Lee.

The morning started with an imminent threat of another thunderstorm. The NEA weather radar showed a massive front coming in from Sumatra, and it had begun raining cats and dogs in parts of Singapore. However, the nature community, being a determined bunch, braved the prospects of planting trees in the heavy rain!



When I arrived at the meeting point, I was pleasantly surprised to see that a decent crowd had already made their way to the Dairy Farm area. The dark rain clouds were also beginning to clear up, and it looked like the event was a go!

MOS Desmond Lee hard at work digging the tree hole

The guests were ferried to the Eco Link by coaches, and before long, the group made its way to the top of the Eco Link, led by MOS Desmond Lee. After the traditional group photo, everyone got busy with the tree planting. MOS was even game enough to plant more than one!

As everyone took in the sights around the Eco Link and the speeding vehicles on the BKE below, I could imagine that this "narrow" 50m wide link could indeed be a bridge across which animals can use to move safely between BTNR and CCNR.



I was also told that the Eco Link will not be opened to the general public and will be kept inaccessible so that the animals that may use it will not be disturbed by human presence. There was also concerns that poachers may also use it as a convenient means to capture their prey.

MOS Desmond Lee entertaining the crowd with his handling of the Oriental Whip Snake

Very soon, all the trees were planted, and the group made its way down to the exhibition area and our much-needed refreshments. As if on demand, a couple of snakes showed up and got the attention of the group, including our Guest of Honour. As it was still cool and cloudy, I didn't manage to spot any butterflies in the area.

As for ButterflyCircle's involvement, members had earlier conducted a pre-construction survey in April 2011 in the area. On that single day alone, a total of 54 species of butterflies were recorded. A few rarities like the Lesser Harlequin, Malay Tailed Judy, Indigo Flash were spotted. After the contractors vacate the site and the vegetation recovers on the Eco Link and the surrounding forests, another survey will be conducted to ascertain the butterfly count.

So there you have it, a biodiversity bridge over an expressway, just for nature. There were concerns that the Eco Link would not be effective or is too narrow for animals to want to use it. Will all this effort will be in vain? To me, it is a little effort that may go a long way in trying to bridge the fragmented nature reserves. These reserves are important in the sense that the forest-dependent butterfly species are dependent on the preservation of this habitat. Although the Eco Link itself may not be directly beneficial to butterflies, since they can easily fly across the BKE, the selection of plants and regeneration of habitats across the bridge may help butterfly populations to spread between the two nature reserves.

An exhibition showing the flora and fauna of the Nature Reserves

The Central Catchment and Bukit Timah Nature Reserves are the last remaining remnants of a once awesome primary forest that covered Singapore. These are certainly worth preserving as our natural heritage, and as a home to an amazing diverse spectrum of flora and fauna. The controversy that surrounds the construction of an underground MRT line cutting across the southern part of the Central Catchment Nature Reserve in the MacRitchie Reservoir area stems primarily from the critical need to protect this precious 'green heart' that is home to an awesome biodiversity. That debate is still ongoing, and it will be another story for another time on this blog.

Text & Photos by Khew SK : Group Photo courtesy of Debby Ng

References and Past Articles about the Eco Link

• From WildSingapore : http://wildsingaporenews.blogspot.sg/2010/12/singapore-bukit-timah-eco-bridge-to.html
• From the Biology Refugia : http://biologyrefugia.blogspot.sg/2009/09/ecological-corridor-for-bukit-timah-and.html
• From SGLinks : http://sglinks.com/pages/1202944-eco-link-bke-links-nature-reserves
• From IYB 2010 : http://iyb2010singapore.blogspot.sg/2010/05/bridge-for-biodiversity-eco-link-to.html

List of Butterflies observed during the pre-construction survey on 9 Apr 2011 :

1) Papilio polytes romulus (Common Mormon)
2) Graphium sarpedon luctatius (Common Bluebottle)
3) Chilasa clytia clytia (Common Mime) (caterpillar)
4) Euploea mulciber mulciber (Striped Blue Crow)
5) Leptosia nina malayana (Psyche)
6) Catopsilia pomona pomona (Lemon Emigrant)
7) Eulaceura osteria kumana (Purple Duke)
8) Eurema blanda snelleni (Three-Spot Grass Yellow)
9) Elymnias hypermnestra agina (Common Palmfly)
10) Elymnias panthera panthera (Tawny Palmfly)
11) Mycalesis mineus macromalayana (Dark Brand Bush Brown)
12) Mycalesis perseus cepheus (Dingy Bush Brown)
13) Mycalesis visala phamis (Long Brand Bush Brown)
14) Mycalesis fusca fusca (Malayan Bush Brown)
15) Orsotriaena medus cinerea (Nigger)
16) Ypthima baldus newboldi (Common Five Ring)
17) Ypthima pandocus corticaria (Common Three Ring)
18) Tanaecia iapis puseda (Horsfield's Baron)
19) Tanaecia pelea pelea (Malay Viscount)
20) Lebadea martha parkeri ( The Knight )
21) Moduza procris milonia (Commander)
22) Hypolimnas anomala anomala (Malayan Eggfly)
23) Athyma nefte subrata (Colour Sergeant)
24) Junonia hedonia ida (Chocolate Pansy)
25) Junonia almana javana (Peacock Pansy)
26) Lasippa tiga siaka (Malayan Lascar)
27) Phaedyma columella singa (Short Banded Sailor)
28) Abisara saturata kausambiodes (Malayan Plum Judy)
29) Abisara savitri savitri(Malay Tailed Judy)
30) Laxita thuisto thuisto ( Lesser Harlequin )
31) Logania marmorata damis (Pale Mottle)
32) Acytolepis puspa lambi (Common Hedge Blue)
33) Caleta elna elvira (Elbowed Pierrot)
34) Eooxylides tharis distanti (Branded Imperial)
35) Iraota rochana boswelliana (Scarce Silverstreak)
36) Surendra vivarna amisena (Acacia Blue)
37) Zizina otis lampa (Lesser Grass Blue)
38) Jamides celeno aelianus (Common Caerulean)
39) Prosotas dubiosa lumpura (Tailless Line Blue)
40) Arhopala centaurus nakula (Centaur Oakblue)
41) Arhopala major major
42) Anthene emolus goberus (Ciliate Blue)
43) Zeltus amasa maximinianus (Fluffy Tit)
44) Rapala varuna orseis (Indigo Flash)
45) Rapala pheretima sequeira (Copper Flash)
46) Hypolycaena erylus teatus (Common Tit)
47) Neopithecops zalmora zalmora ( The Quaker)
48) Pelopidas mathias mathias (Small Branded Swift)
49) Tagiades japetus atticus (Common Snow Flat)
50) Tagiades calligana (Malayan Snow Flat)
51) Hasora badra badra (Common Awl)
52) Iambrix salsala salsala (Chestnut Bob)
53) Potanthus omaha Omaha (Lesser Dart)
54) Taractrocera archias quinta (Yellow Grass Dart)

Down Memory Lane - Small Red Bob

Down Memory Lane
The Small Red Bob (Idmon obliquans obliquans)

This small and rather insignificant skipper was recorded in Singapore by the early authors. It resembles the related species from the genus Iambrix, of which there are two representatives in Singapore - Chestnut Bob and Starry Bob. The Small Red Bob is predominantly dark reddish-brown, with a short orange-red post-discal band on the forewing. It flies mainly along open paths in forested areas and is not uncommon.  It flits from perch to perch and often sunbathes in the usual skipper fashion.

It is likely that the Small Red Bob's caterpillars feed on grasses. It was found in Singapore in the past, but has not been reliably observed over the past 4-5 decades. It may have been overlooked as it is not a particularly spectacular looking butterfly.  But what caused this species to disappear from Singapore? Will it be back here again one day? Or will it remain only in our memories and is gone forever from Singapore?

Butterflies Galore! : Common Palmfly

Butterflies Galore! 
The Common Palmfly (Elymnias hypermnestra agina)

The Common Palmfly is quite widespread in Singapore, and is observed in urban parks and gardens, particularly where its caterpillar host plants (various palms) are cultivated. A favourite host plant is the Yellow Cane Palm (Dypsis lutescens) which is often used as an ornamental palm in home gardens. The butterfly has a slow flight, although it is very skittish and not easily approached.

The upperside of the Common Palmfly features dark bluish black forewings with light blue submarginal spots and reddish purple hindwings. The underside is reddish brown with light grey striations. There is usually a white spot at the costa of the hindwing, although in some individuals, this spot can be missing. This shot of the Common Palmfly was taken by young ButterflyCircle member Jerome Chua.

Life History of the Large Snow Flat

Life History of the Large Snow Flat (Tagiades gana gana)

Butterfly Biodata:
Genus: Tagiades Hübner, 1819
Species: gana Moore, 1866
Sub-species: gana Moore, 1866
Wingspan of Adult Butterfly: 38-45mm
Caterpillar Local Host Plants: Dioscorea pyrifolia (Dioscoreaceae), Dioscorea orbiculata var. tenuifolia (Dioscoreaceae) and other Dioscorea spp.

Physical Description of Adult Butterfly:

Above, the wings are brown with obscure post-discal and discal spots in darker brown. On the forewing, there are three white hyaline sub-apical spots in spaces 6,7,8. On the hindwing, the tornal area is whitened and there are black marginal spots at the end of veins 2, 3 and 4, and in some specimens, another spot at the end of vein 1b. Below, the wings are similarly marked as per above but with the whitened area on the hindwing extended to the basal area and almost to the costal margin.

Field Observations of Butterfly Behaviour:  
This species is common in Singapore and can be found in the forested areas in the Central Catchment and Bukit Timah nature reserves, and several other sites across the island. The adults are rapid flyers and are more active in the cooler hours of the day. As is the case for the other Tagiades species, the adults have the habit of perching on the underside of a leaf between flights, and with wings opened flat. The adults are often seen visiting flowers for nectar.

Butterflies Galore! : Plain Palm Dart

Butterflies Galore!
The Plain Palm Dart (Cephrenes acalle niasicus)

The Plain Palm Dart is one of two extant species of the genus Cephrenes in Singapore. Males of this species are often confused with the commoner Telicota species which are lookalikes and not easy to identify when in the field. However, the Plain Palm Dart is slightly more unique than the other species in that the females are purple-brown and can be distinguished immediately. The species can be found in urban parks and gardens, and is also quite regularly observed on Pulau Ubin, especially when there are flowering Syzygium trees.

This female Plain Palm Dart was photographed by ButterflyCircle member Loke PF. The butterfly is feeding on the flower of a common "weed", Bidens sp. Females are rarer than males.  The caterpillar of the Plain Palm Dart feeds on the common coconut palm (Cocos nucifera) and one of the "fan" palms (Livistonia sp).  The life history has been recorded here.

Butterflies Galore! : Archduke

Butterflies Galore!
The Archduke (Lexias pardalis dirteana)

The large, robust-bodied butterflies of the genus Lexias are forest-dependent species that seldom stray from the sanctuary of the forested nature reserves of Singapore. They are largely ground feeders, preferring to forage amongst leaf litter and fallen fruits on forest floor. Two of the three extant species of the genus display distinct sexual dimorphism in that the male and female look very different from each other.

This shot, taken by ButterflyCircle member Nelson Ong, shows a male of the Archduke feeding on some liquid nutrients on a tree trunk. The males are velvety black above with a prominent blue marginal border on the hindwing, which continues to the termen of the forewing. The Archduke is a powerful flyer and is usually skittish.

Butterfly of the Month - September 2013

Butterfly of the Month - September 2013
The King Crow (Euploea phaenareta castelnaui)

The first week of September saw another unprecedented flood in Singapore - this time on the western side of the island near the National University of Singapore. For the first time, an entire major expressway was completely shut down to all classes of vehicles for about 40 minutes. The Ayer Rajah Expressway, or the AYE was inundated by the sudden downpour in the early morning hours, and coupled with the high tide, caused the flooding of all four lanes.



This 'rainy season' that is known as the South-West monsoon has seen several wet days in September, including weekends, that caused ButterflyCircle members to be cooped indoors (rather unhappily) instead of going out on their regular outings. The 'Sumatras' as these seasonal monsoon winds are called, are forecasted to taper off in October as the inter-monsoon lull will hopefully bring better weather.



For the nature groups, the concerns over the 50km Cross Island MRT line that will start in Changi and end in Jurong will be given a short reprieve as the Land Transport Authority announced that a two-year Environmental Impact Assessment will be conducted to ascertain the impact on biodiversity and the habitats where the line cuts through MacRitchie Nature Reserve. Some initial thought-provoking questions can be found on this site. The NSS also published a position paper on the concerns regarding the initial soil investigation works, as well as the potential ecological damage that the underground tunnelling work may cause during the construction stage.



Dr Wee YC, the author behind the Bird Ecology Study Group, has also penned a series of articles showcasing the biodiversity that may be lost with the Cross Island Line, if it goes ahead as planned. His latest article is posted here. A site to showcase the biodiversity of MacRitchie forest, and to lobby concerned nature enthusiasts and anyone who shares the common cause has been set up. It's called the Love Our MacRitchie Forest site.



Our feature butterfly for the month is the largest species in the genus Euploea often referred to as the 'Crows'. The genus features large distasteful butterflies, usually black or blue, with white spots or stripes on their wings. The King Crow (Euploea phaenareta castelnaui) is the largest member of the genus, with a wingspan between 90-105mm.



The King Crow is a moderately rare species, although it can be regularly observed in local areas, particularly where its caterpillar host plant grows. It is often spotted in the back-mangrove areas of Pasir Ris Park, Pulau Ubin and even in urban areas in the vicinity of its host plant, the Pong Pong Tree (Cerbera odollam).



On the upperside the predominantly dark brownish-black butterfly features a series of violet-tinged apical spots on the forewings. There is a series of white marginal and submarginal spots on both wings. The spots on the underside are smaller although there are some individuals where some of these spots appear violet in colour.



On the upperside of the hindwings, male King Crows feature a raised scent patch in the cell, and there is a certain obvious discolouration at the tornal area of the hindwing. The forewing dorsum of the female is straight, whilst in the males, the forewing dorsum is strongly bowed. Females are typically larger, with a wider wingspan.



The King Crow flies slowly but can be alert and skittish. It tends to fly at higher levels amongst the treetops, stopping occasionally to rest with its wings folded shut. At times, the butterfly is observed to rest with its wings opened flat, as if to sunbathe. It can also be observed feeding on a variety of nectaring plants, and is particularly attracted to the flowers of the Syzygium trees.



The caterpillar host plants were previously planted as a roadside tree and in some housing estates. But in recent years, the tree has fallen out of favour, as the large apple-like fruits have been known to drop and damage parked cars, prompting the authorities to remove the Pong Pong as a roadside tree. It is now more often seen in backmangrove areas and parks, away from carparks.



The complete life history of the King Crow has been recorded in this blog here.  The photo below shows the eclosion sequence of the King Crow.

Text by Khew SK : Photos by Sunny Chir, Khew SK, Loke PF, Bobby Mun, Horace Tan, Tan Ben Jin & Benedict Tay