Tuesday, November 22, 2005

Pseudokarst Granite

Ubin Jetty at low tide, exposing large granite boulders commonly known as "flute rocks" with vertical grooves or "flutings". Photo by November Tan

As a person arrives at the Pulau Ubin jetty, the first thing that may capture their attention are the large granite boulders that line the coast of the island. These are we commonly referred to as flute rocks. It has always been mentioned by various sources such as Dr Chua Ee Kiam that these rocks are really unique features and has been described in various books about Singapore such as Edmund Waller's "Landscape Planning in Singapore". In fact, according to this quote from a book on coastal features around the world by Heather Viles and Tom Spencer (1995), these flute rocks are indeed rare features even around the world.

"Granite cliffs in Singapore with its presence of deep 'pseudokarstic' fluting on the granite, extending way below present sea level, bears witness to the antiquity of their formation." (Page 117)

There are also mentions of Pulau Ubin's pseudokarst features in a journal article by H.M. French and M. Guglielmin (2002) on "Cryogenic grooves on a granite nunatak, Northern Victoria Land, Antarctica" published in Norsk Geografisk Tidsskrift.

Our coastal features does appear to be well known around the world. Not only are these granite features popular, we also appear to be along the ranks of famous coastal locations in terms of having a rock shore environment and shore platforms as again Viles and Spencer (1995) writes that "shore platforms are found in many parts of the world including Australia, Antarctica, Norway and Singapore." (Pg 111)

They also quoted Swan (1971) that while most cliffs in the humid tropics are not being undergoing active erosion activities, Singapore is one of such unique exceptions where "active" cliffs are found on relatively exposed coasts. (Swan, 1971)

These brings to mind the few remaining rocky shore beaches and cliffs that remains in Singapore today, such as that in Labrador Park, Changi and Sentosa. Hopefully these cliffs would remain for some time to come along with the rare pseudokarst granite "flute rocks" of Ubin.

  • Viles, H. and Spencer, T. (1995) "Coastal Problems: Geomorphology, Ecology and Society at the Coast" Edward Arnold
  • Swan S.B.StC. (1971) "Coastal Geomorphology in a Hot Humid Low-energy Environment: The Islands of Singapore" in Journal of Tropical Geography, Vol 33
  • French, H.M. and Guglielmin, M. (2002) "Cryogenic grooves on a granite nunatak, Northern Victoria Land, Antarctica" Norsk Geografisk Tidsskrift
  • Monday, November 21, 2005

    Food for thought

    Would we now expect to see an increased number of tourists from India to Pulau Ubin?


    Great film! Now let's visit Singapore
    Visitor numbers from India up by 24%, even as S'pore courts Bollywood, film fans
    7 November 2005
    Today Online
    By Jasmine Yin

    WHAT Winter Sonata did for South Korea, the Singapore Tourism Board (STB) hopes Bollywood blockbusters like Krrish will do for Singapore.

    If the board gets its way, fans of the upcoming flick will flock to Singapore to re-live the sights and sounds their movie idols experienced here. About 60 per cent of the film — which is directed by Rakesh Roshan and stars Hrithik Roshan and Priyanka Chopra — is currently being shot in Singapore.

    Local attractions featured include the Singapore Zoo, Changi Airport, the Esplanade, Clifford Pier, Chinatown, Pulau Ubin and Orchard Road.

    Krrish is the first Indian mega movie to be shot under STB's $10-million Film in Singapore! Scheme, launched last May to generate more awareness of Singapore in STB's key target markets.

    The scheme, which will disburse the $10 million over three years, will subsidise up to half of the expenses incurred by international film companies during their shoots here.

    "India is among Singapore's top 10 visitor-generating markets … (and) promises great potential to the tourism sector. The Indian film industry is also one of the most dynamic, prolific and illustrious in the world and has a wide international reach beyond India," STB's brand management director Bill Ang told Today.

    "We are always keen to work with quality productions which are aired in our key target markets and which showcase Singapore as a fun and unique destination."

    Latest statistics from STB show that visitor arrivals from India grew by 24 per cent for the month of September, as compared to last year.

    The top five visitor-generating markets for September were Indonesia, China, Australia, Japan and Malaysia.

    Mr Ang said that several film companies in various overseas markets have indicated strong interest in the scheme. So far, STB has approved nine projects, with a few more under evaluation.

    These projects, which must showcase Singapore in positive light, are for distribution in Europe, China, India and South-east Asia.

    STB has previously worked with major international networks like MTV, CNN and National Geographic to create programmes that build awareness of Singapore as an attractive destination. Its regional offices have also collaborated with national networks in their respective countries, such as China's Sun TV and India's Zee TV, on programmes such as travelogues and game shows.

    Using entertainment culture to attract tourists is not a strategy unique to Singapore. One needs only to turn to South Korea to witness the phenomenal effects that its entertainment stars, who are fervently embraced across the region, have had on its tourism industry.

    Popular culture has become big business in South Korea, with more than 100 million followers in Asia of its programmes and music, and a fast-growing cultural industry worth $122 million last year.

    Tour packages themed around its popular dramas, such as Winter Sonata, were snapped up by avid fans flocking to visit these filming locations. Tourist arrivals increased by more than 40 per cent in the first eight months of last year, as compared to the same period in 2003.

    When asked to assess the impact of STB's one-year-old film scheme, Mr Ang said it was "still too early" to determine the impact on Singapore's image as a destination because some of these projects have either just completed filming or are still in the production stage.

    He added: "Our officers in international officers are always on the look-out for opportunities to attract film-makers to Singapore and have been actively meeting up with the film industry in their respective markets to share the scheme with film-makers and producers."

    Copyright MediaCorp Press Ltd. All rights reserved.

    Source: Today

    Friday, November 18, 2005

    Bird flu checks for migratory birds stepped up

    The Straits Times
    18 November 2005

    EVERY year, about 20,000 birds flying south for the winter take a breather at the Sungei Buloh Wetland Reserve in Kranji. Many others stop off at Pulau Ubin and the Changi coastal area during the September-March migratory season.

    It might be a natural marvel, but this year it brings with it the potential threat of bird flu.

    To deal with this threat, Singapore's Agri-Food and Veterinary Authority (AVA) and the National Parks Board have set up an ongoing surveillance programme to test wild birds for the virus at the wetland reserve. During this peak migratory season, officers are carrying out weekly tests.

    They have also extended surveillance efforts to Pulau Ubin and widened their net to test resident birds around the island throughout the year.

    More than 400 birds have already been given a clean bill of health since testing started in August 2003.

    The deadly virus can infect many species of birds. In general, domestic poultry such as chickens and quails are most susceptible. Many species of waterfowl, especially wild geese, ducks and swans, may carry the virus without appearing to be ill.

    However, the current H5N1 strain also appears to cause severe disease even in wild waterfowl. Why this is so is not well understood.

    The AVA has given the assurance that Singapore is free from bird flu and it is safe to visit nature reserves.

    However, it has warned that people should wash their hands thoroughly with soap if they come into contact with birds.

    Thanks to: WildSingapore

    Singapore steps up testing of wild birds for bird flu as winter season approaches

    By Lee Ching Wern
    Today Online
    18 November 2005

    As the danger of bird flu infiltrating Singapore heightens with the arrival of the winter season, the Government is stepping up the testing of wild birds for avian flu at wetlands reserves islandwide.

    During the migratory season from September to March every year, about 20,000 birds flying south for the winter stop over at the Sungei Buloh Wetland Reserve in Kranji for a breather. Migratory birds, in particular, are a cause of concern to the Agri-Food and Veterinary Authority (AVA) because these birds could have come from countries affected by the disease.

    To ensure visiting birds do not spark off a bird flu epidemic here, the AVA, in collaboration with the National Parks Board (NParks), increased its surveillance on these birds about two months ago.

    In addition, animal health officers from the AVA perform weekly tests on the birds' faecal and blood samples. These officers visit Sungei Buloh and Pulau Ubin to trap and collect samples from migratory birds as well as resident birds such as mynahs and crows. Swabs of stool and blood samples from the birds are then sent to the AVA's Animal and Plant Health Centre for testing.

    So far, the 411 birds tested here have been found to be clear of the H5N1 virus.

    "There is no control over the movement of migratory birds. It is likely that they are infected from other infected migratory birds or domestic poultry," said Mr Madhavan Kannan, head of AVA's Centre for Animal Welfare and Control.

    Domestic poultry such as chickens and quails are the most susceptible to bird flu. Meanwhile, many species of waterfowl, especially wild geese, ducks and swans, may carry the virus without clinical signs.

    "We're concerned migratory birds may spread it to poultry farms, so the critical point is to stop that avenue," said Mr Madhavan. "For that, we've got all our farms to take bio-security measures so if some birds have it, the trigger point won't be set."

    Until the whole bird flu scare blows over, Singapore will continue with the weekly surveillance.

    Source: Today

    Living on the Edge: The Straw-headed Bulbul in Pulau Ubin

    Review contributed by Mr Budak

    Straw-headed Bulbul. Picture by Sian, courtesy of Dr. Ho Hua Chew

    Singapore tends to be seen as a place where wildlife is barely hanging on. Its native megafauna has long been extinguished, while a handful of endemics cling to the precipice of extinction in the island's fragile central reserves. So it might surprise some that a species of global conservation significance is actually finding sanctuary in Singapore, even as it faces extermination in neighbouring countries.

    The creature in question is an unspectacular songbird called the straw-headed bulbul (Pycnonotus zeylanicus), which has found a safe haven in Singapore's wooded areas, in particular Pulau Ubin. Remarkably, there is no record of this species in Singapore prior to 1951, and even till to 1970s, the bulbul was not known to be common, even on Ubin. A bird survey in 1992 counted 50 birds on Ubin, which fell to 30 in 2000. However, the population rebounded to about 32 breeding pairs in 2001, whilst the mainland recorded a estimate of 76-93 birds.

    Revealing these figures, Dr. Ho Hua Chew of the Nature Society of Singapore shared the background behind a recent field study he conducted on Pulau Ubin to analyse the habitat preferences and prevalence of the bulbul. The largest bulbul species in Southeast Asia, the straw-headed bulbul is a perky brown-bodied bird boasting a yellow crown, white throat and a black streak across its cheek.

    Liquid gold
    The bulbul's rich, melodious song, described as liquid gold, is more often heard than the bird itself, and has led to the species' disappearance from of its former range. Once found throughout the Sunda Shelf from Burma to Borneo, the bulbul is now believed to be extinct in peninsular Thailand and Java and near extinction in Sumatera. Veteran birder Ivan Polunin notes that suitable habitats in Southwestern Johor are also devoid of the bird. Habitat destruction such as clearing of secondary forests and mangroves is one reason for this fate, but the widespread practice of trapping songbirds for the pet trade is thought to be a significant factor in the bird's rarity, a fate shared by the once common white-rumped sharma. The bulbul is now classified under the CITES Division 2, which allows for trapping and trade of the species under specified permits and quotas.

    A mosaic landscape
    To obtain updated data on the bird's population and habitats on Ubin, Dr. Ho conducted extensive field work on the island in 2001-2002. The study sought to determine the extent of the species in Ubin and why the island is proving to be a stronghold for the bird. There is a "need to see how the species fits the island; it's preferred habitats, nest sites, habits etc..," Dr. Ho said at his talk this Wednesday evening at the NSS office in Geylang.

    Firstly, it was necessary to develop a profile of Ubin's biophysical environment. The island sits between mainland Singapore and Southern Johor, and according to Dr. Ho, serves as a kind of stepping stone that allows species from Johor to disperse into Singapore.

    Ubin spans some 102 hectares and a human population of about 500. The island serves as a refuge for many species once found on the mainland, including the wild boar, oriental pied hornbill, jungle fowl, buffy fish owl and white-rumped sharma. Smallholdings, rubber estates, coconut plantations and orchards used to dot the island, but many of these are now disused and dismissed to the care of mother nature, whose tendrils and creepers are reclaiming what was once her virgin territory.

    Dr. Ho pointed out four primary threats to wildlife on Ubin. There is the encroachment of modernisation in the form of future high rise developments and resort centres (e.g. the Lagoon Resort). Land reclamation is also changing the landscape; for instance, a part of Pulau Ketam (an islet off Ubin) has been cleared of its original mangroves and turned into a landfill for no discernible purpose. Large camping grounds also play a role; Dr. Ho notes that the NPCC campground on the northeast of the island required the clearing of nearly 30 hectares of secondary forest. Finally, as visitors to the island and observers of its residents' backyards would know, there is poaching. In Singapore, however, the straw-headed bulbul is not a popular cagebird.

    Dr. Ho divides Ubin into three broad biophysical sections. The island's narrow centre is dominated by mangroves, ponds and other wetland, serving as a sort of watery gulf between the extremities. The western side of the island has been largely given over to the Outward Bound School, for better or worse, and is covered by secondary forest (led by Adinandra belukar and Caryota palms), abandoned orchards and wasteland that is being recolonised by fast growing Acacia and Paraserianthes falcataria (aka Albizia) trees. The east end contains higher ground, secondary forest and old rubber plantations. A 'mosaic' landscape is how Dr. Ho terms the island's features. His survey estimates the following land composition: rubber plantations (32%), secondary forest (14%), mangroves (14%), orchards (12%), open ground (10%) and wet areas (17%).

    Picture by Sian, courtesy of Dr. Ho Hua Chew

    Bulbul ecology and observation
    What we know about the straw-head bulbul is that the bird is an omnivore, feeding on fruits, berries, insects, spiders and other small animals. The bird is often seen in territorial pairs, and nests all year round, although February to April appear to be the main breeding months for the Singapore population. The nest, a cup-shaped mesh of leaves, plant fibres, roots and grasses, is built 1-5 metres above the ground and the normal clutch size is two. After the nesting period, the birds may move around in groups of 3-8 individuals.

    Describing his methodology in surveying Ubin's habitats, Dr. Ho said he employed three ways to observe the birds: the archaic 'look-see method', territorial mapping of observed pairs and playback of recorded birdsong to register vocal responses. Several variables pertaining to the nature of the habitats surveyed were gathered and the data analysed by a logistical regression programme to ascertain correlations between the bulbul's presence and the characteristics of the habitat. The variables were collated from 30 randomly-selected 'presence' sites (locations where birds have been sighted) as well as 30 random 'absence' sites (which serve as a control).
    The result allowed Dr. Ho to build a model that would help predict the probability of the bulbul's presence in a particular habitat, given knowledge of certain variables. After mapping out both presence and absence sites on a map, he determined that at least 32 clusters (one breeding pair each) existed on the island.

    The study's rationale is based on the need to clarify the ecology of the bulbul in terms of its population density, breeding success and feeding patterns in carefully evaluated habitats. Information about where the birds feed and nest in relation to the island's habitats would hopefully aid in the design of reserves as well as habitat management and future efforts to secure viable populations of the species. Prior to Dr. Ho's study, there were no ecological studies on the bulbul's population in Ubin and Singapore. On the mainland, the bird is known to exist in scattered groups in Bukit Batok, Bukit Timah and the Botanic Gardens. Ubin was thus chosen for its biogeographic bridging role between Johor and Singapore as well as its relatively high concentration of bulbuls.

    Birds on the edge
    Dr. Ho observed that in rubber plantations, pairs were more dispersed, compared to birds living in secondary forest, which had more clustered populations. In addition, the birds tended to be found at the edge of habitats, rather than the centre. The birds were commonly seen at the edges of plantations and the fringes of mangrove swamps and secondary forests. In contrast to observations in other countries, the Ubin bulbuls preferred low ground, being absent from areas more than 20 metres above sea level.

    The population and density of bulbuls on Ubin were recorded as follows:
    SectorPairsHectareDensity (per Ha)
    Total321020 0.03

    The specific habitats frequented by the birds were recorded.
    Secondary Forest
    Number of Pairs

    The variable data collected from the 30 presence and 30 absences sites for logistical regression of habitat preferences were:
    • Altitude
    • Nearest edge (of habitat)
    • Tree density
    • Tree richness
    • Undergrowth density
    • Nearest waterbody
    • Nearest coast
    • Nearest track/road
    • Nearest building
    The crunched numbers indicated that only four variables were correlated to the bulbul's presence: altitude, the nearest edge, tree density and tree richness. A mathematical model was formulated to predict the relative probability of the bulbul's presence given data on these four relevant variables. Dr. Ho noted that the birds seem to be fairly tolerant of human activity on Ubin, being indifferent to the existence of tracks, roads and buildings. Ubin's bulbuls were also indifferent to the proximity of waterbodies, in contrast to studies in Borneo which found the bird to be highly riverine, never straying more than 20 metres beyond a riverbank.

    Altitude proves to be negatively correlated to the bulbul's presence, with a decreasing chance of sightings as one enters higher ground. This feature may be linked to the species' marked presence for edge habitats; habitat centres on the island also tend to be located on high ground.

    Edges, however, appear to be the single most vital feature of bulbul habitats. Dr. Ho notes that the probability of sighting a bulbul rises strongly as one approaches the fringes of a habitat. So what matters is not just the habitat itself, but also the adjacent habitats with which it borders. For instance, a habitat that borders a mangrove swamp would yield a 33% chance of a sighting. Habitats fringed by open ground were also favourable spots (see table below).

    Open ground
    Secondary forest
    Rubber Plantation

    Tree richness (i.e. the number of tree species in a habitat) is positively correlated with bulbul presence. Dr. Ho believes this stems from the greater availability of food sources in heterogeneous forests, in contrast to the uniformity of Acacia secondary woodland and rubber plantations. The Ubin bulbuls also prefer a lower tree density, contradicting earlier observations that the bulbul is an early successional species that colonises newly abandoned land.

    Conservation strategies
    Dr. Ho outlined a number of conservation strategies based on his study's conclusions. Firstly, it is important to preserve tree diversity as well as maintain a varied number of habitats. Thus, Ubin's existing mosaic of landscapes consisting of patches of woodland, orchards, mangroves, old plantations and open areas should be retained in preference to monocultured habitats. And rather than allowing nature to overwhelm the entire island and recreate an endless firmament of forests, the existing orchards and plantations should be managed to control tree density and preserve the borders between varied habitats. Such management would also have to take into account the preferences of other species which may prefer denser habitats, such as the jungle fowl and white-rumped sharma.

    The birds' implied indifference to human activity, however, does not mean that the erection of high rise developments would necessarily prove insignificant to the welfare of the island's species. What remains as well is the question of whether the bulbuls in mainland Singapore share the preferences of their Ubin counterparts. Given the species' precarious situation in much of its former range, the maintenance of suitable habitats on Ubin and Singapore may well prove vital to the survival of the straw-headed bulbul.

    Thursday, November 17, 2005

    Singapore steps up bird flu tests among local and migratory birds

    By Rita Zahara
    17 November 2005

    SINGAPORE : Tests on local and migratory birds for bird flu have been stepped up islandwide, from once a fortnight to once a week.

    The tests by the Agri-Food and Veterinary Authority (AVA) and NParks also include poultry raised on farms and resident birds like mynahs and crows.

    Some 100 species of migratory birds, among them the Siberian Marsh Sandpiper, flock to Singapore during the winter months between September and March each year. Starting from the northern hemisphere, they travel some 6,000 kilometres from areas like Russia, Siberia and Mongolia to South-East Asia, with stopovers in Thailand, Malaysia, Singapore and Australia.

    Sungei Buloh is one of the places migratory birds like to visit to rest and feed. Some might stay for a few days before flying off; others are known to remain here till the end of March. It is estimated some 20,000 migratory birds fly into Singapore, with the November and December months being the peak period.

    Since there is no guarantee the birds are free of the avian flu virus, AVA is not letting its guard down. Said K Madhavan, head (Animal Welfare and Control Centre), AVA, "We're concerned that the migratory birds, if infected, would spread it to our poultry farms. The critical point here is to stop that avenue and for that we have got all our farms to take bio-security measures so that in the event that some migratory birds have this virus, they will not affect our farms and the trigger points will not be set."

    So while the birds are in transit, NParks randomly captures different species and clips them with identification tags. AVA then takes swabs from the birds, and these samples are processed and tested. The samples are injected into eggs, which act as testbeds for viruses. The eggs are monitored to see if they grow healthily. If present, the bird flu virus can be detected between 24 to 72 hours.

    Said James Gan Wan Ming, senior conservation officer, NParks, "This is a cooperative and collaborative project in which AVA is riding on Sungei Buloh's existing bird ringing programme. This is our part to enable AVA to do the necessary tests."

    Since the AVA-NParks partnership began two years ago, more than 400 birds have been tested.

    All were negative for the virus.

    But as long as countries in the region are affected by the avian flu, AVA says the weekly surveillance will continue.

    Source: CNA /ct

    Tuesday, November 15, 2005

    Talk on the Straw-Headed Bulbul on Pulau Ubin

    Date: 16 November 2005, Wednesday
    Time: 7.30pm
    Venue: NSS office, The Sunflower
    Organized by: Nature Society (Singapore)
    Speaker: Dr Ho Hua Chew

    The Straw-headed Bulbul is the most conspicuous and loudest bulbul on Pulau Ubin. The species is doing relatively well on the island. It is also a popular cagebird. Sadly, it has become endangered in many areas of its distribution range and is considered extinct in Thailand and Java where it was once common. It is now globally vulnerable. The talk focuses on its habitat requirements and the possibility of Pulau Ubin as a model protection area for this lively and bubbly species.

    All are welcomed.

    How to get there?

    510 Geylang Road, #02-05 The Sunflower, Singapore 389466