Commentary: Applicability of points raised in an American dengue-related article to the Singapore context

Hi guys! I just read “Dengue, Urbanization and Globalization: The Unholy Trinity of the 21st Century” by Gubler (2011). It’s a fun and easy-to-read article, and I felt that many of the statements raised by the author (mostly focused on the American context) were interesting to discuss in relevance to Singapore.

First, Gubler points out that “The dramatic global geographic expansion and the increased incidence of epidemic dengue coincided exactly with urban growth and globalization”. Similarly, we have seen isolated cases of malaria surfacing in our small and densely-populated island, usually from infected foreigners travelling to Singapore. With the possibility of microbial mutations, we may soon witness the re-emergence of once-eradicated diseases on our shores. So, is it wise for our country to invest resources in mandatory year-round screening of arrivals at the airport, and quarantine those that display symptoms for highly-communicable and serious illnesses? After all, it only takes one person to start an outbreak in population-dense Singapore. What are some of the barriers that this initiative will face?

Second, Gubler makes some points which he believes are the main cause for America’s failure in controlling the flourishing of mosquito vectors. I highlight two of them here:

  1. The “lack of political will and thus resources”
  2. “Too much emphasis on high technology such as space spraying of insecticides”

I believe that point a) was made with reference to the successful eradication program of Aedes aegypti in America, which led to increasing apathy and complacency towards subsequent mosquito control efforts. However, in the case of tropical Singapore, we seem to be fighting a year-round war with the dengue virus. Even though there are ‘off-peak’ periods in the emergence of new dengue cases, the risk of infection is still present.

As for point b), Guber mentions that “successful mosquito control programs were replaced by emergency space spraying of nonresidual insecticides in response to reported cases of dengue”, which had “high visibility and was very popular politically”, but lacked efficacy as it failed to target mosquitoes which were seeking refuge within homes. This point resonates strongly with me, as I recall frequently seeing pest-control workers years ago lugging huge canisters on their backs and fogging up neighbourhoods to kill adult mosquitoes, or applying some sort of chemical to public drains and gutters, presumably to eliminate mosquito larvae. Back then, I was wondering if such efforts were really useful, since I was bitten at home shortly after a fumigation event near my house. However, I don’t seem to see these efforts recently, at least not in my neighbourhood. Instead, some strange sort of container (possibly a mosquito trap?) by the National Environment Agency (NEA) has been placed near my lift- with no explanatory text whatsoever.

IMAG6415 IMAG6416

Fig.1. Mosquito trap-like container found near my lift

There has also been a strong focus on community outreach, such as the highly publicised “5-step Mozzie Wipeout” campaigns, (somewhat intimidating) door-to-door surveillance by NEA officers, as well as huge banners which state the colour-coded ‘dengue alert’ status of the neighbourhood. Thus, I believe that Guber’s statement does not hold for Singapore. In fact, the situation seems to have been reversed, with more focus being placed at individual household levels.

Fig. 2. The ubiquitous “5-step Mozzie Wipeout” banner which can be found at many bus stops and on SBS buses (Photo credit: NEA)

In all, I feel that these two points raised in Guber’s article with regards to the causes for America’s failure in controlling mosquito populations generally have limited applicability to the Singapore context. This is a good thing, for it means that our government has already taken steps to resolve and/or prevent them. In fact, the NEA seems to be doing quite a fair bit in terms of managing the dengue situation, as observed from their multi-pronged approach. However, is it working effectively? One 47-year-old man has already succumbed to the dengue virus this year, and a shocking 628 dengue cases were reported between Jan 10 to 16, which is the highest weekly figure in more than a year. Furthermore, with the onset of El Nino, which has caused an increase in temperature and thus favourable mosquito breeding conditions, the problem is expected to worsen.

With these issues in mind, should any changes be made to our current approach, which is largely remedial (e.g. focused on vector-elimination and medical treatment)? Should the government focus on pre-emptive measures instead (e.g. vaccines)? Also, should extra effort be made to provide safety-nets for more vulnerable members of public, such as immuno-compromised elderly who live alone?



Impact of urbanization on developmental responses

Embryonic and larval development form a significant part of many species’ life history. Animal development is governed by gene expression within the cell that specifies tissues and regulates cell differentiation. However, it is increasingly being recognized that environmental factors such as temperature, photoperiod, diet, population density, or the presence of predators, play a major role in determining gene expression patterns thereby producing variation in developmental responses and phenotypes. With increasing urbanization and associated ecological changes, species might further alter their development to adapt to new environmental challenges presented by urbanization.

One example of development being affected by the environment is temperature-dependent sex determination where at one temperature, embryos become males and at another temperature, they become females. For example, in painted turtles, Chrysemys picta, the sex ratio is linked to temperature, with the sex ratio become increasingly female when temperature increases. Habitat modification during urbanization changes the temperatures of their nest sites and may lead to biased sex ratios. Anthropogenic alteration of habitats can therefore disrupt the developmental responses of animals.

Hatching of the embryos can also be affected by environmental cues such as increased presence of predators. For example, the embryos of the red-eyed tree frog, Agalychnis callidryas, sense the presence of the snake and vigorously shake in their egg cases when attacked. They hatch prematurely into the water to prevent getting eaten. However, premature hatching also means that hatchlings are at higher risk of being eaten by the aquatic predators once in the water. Variation in hatching rates is also observed in other species at different temperatures and when there are environmental contaminants. Moreover, the morphology of the tadpoles is also altered in the face of these environmental assaults. Introduction of novel predators or altered abiotic conditions caused by urbanization therefore easily influence the developmental behaviours and phenotypes of the species.

Source: Karen Warkentin

Figure 1: Embryos of the red-eyed tree frog. At early developmental stages, they are already actively responding to the environment, which is critical to its long-term survival. Source: Karen Warkentin

Video on how the embryos of red-eyed tree frog hatch prematurely, in the presence of the parrot snake as a predator, so as to escape the predator attack.

As seen, development and the environment is intrinsically linked and environmental cues play a role in determining the developmental trajectory of the species. As we become more aware of the how development is critically influenced by the environment, we are also realizing that increasing urbanization may be affecting species in more ways than we think.

What other ways do you think urbanization could be affecting developmental responses?


Gilbert, S. (2001). Ecological Developmental Biology: Developmental Biology Meets the Real World. Developmental Biology 233, 1-12.

Kolbe, J., and Janzen, F. (2002). Impact of nest-site selection on nest success and nest temperature in natural and disturbed habitats. Ecology 83, 269-281.

Warkentin, K. (2005). How do embryos assess risk? Vibrational cues in predator-induced hatching of red-eyed treefrogs. Animal Behaviour 70, 59-71.

Purpose of greening

So in class I asked Prof Tan about his thoughts on increasing indoor greenery to help increase the greenery of Singapore. He said that while indoor greenery like green walls can help with the greening efforts, it needs to have a specific function and cannot be installed for the sake of being there.

It got me thinking about the greening efforts by some buildings in Singapore and whether those greening efforts are for a functional use or merely for aesthetic appeal or to spread the message “Hey, we have some plants on our buildings. We are a green building!”. Can the pursuit of greenery be too tokenistic? Do developers/building owners blindly chase the greening fad just to be ‘in’?

If you take a look at Kent Vale, the greenery on the sides of its buildings are poorly maintained and, well, almost non-existent. What purpose does it serve? Aesthetics? The CREATE building in UTown, too, has some plants on the sides of its building but they are small in numbers and honestly do not look very appealing to me. What purpose does it serve, then?

What do you guys think? Should there be a purpose behind every act of greening? Do you think developers might be guilty of blindly chasing the green fad without the adequate technical knowledge required?


Effectiveness of Rooftop gardens

Rooftop gardens have increasingly becoming a trend in the housing estates, hotels and corporate buildings. All these are mainly due to the promotion of sustainable living and conservation of nature by the government agencies. The Building and Construction Authority (BCA) Green Mark scheme was implemented in 2005 to create a rating system to evaluated the environmental sustainability of the building. This sparks of  industries interest in trying to reduce their carbon footprint by using sustainable materials, installing energy efficient appliances and increasing green spaces in the building. One of the more innovative ways is to build a roof top garden at the top of the building.

Green roofs serve many purposes – helps in storm water management as water can be stored by the substrates, mitigate the Urban Heat Island effect that is a major concern in cities, increase recreational spaces for the community. However, there are also many speculated cons about rooftop gardens. It will increase the cost of water drainage systems, increase insurance costs due to possible accidents that can happen at a high rise building and also the weight of structures which can put a strain on the building.

Now the problem comes with regards to practicality and feasibility issues. Is it worth spending so much capital on rooftop gardening and maintenance as compared to investments in other areas of maintenance and expansion such as the reservoirs, streetscapes and nature corridors ? This boils down to different perspective and what is best for the country. Personally, from the society perspective, I feel that green roofs are still a rather novel idea which is attractive to people and can play a significant role in the well-being of individuals.

Having said that, rooftop gardens do actually have the means to generate revenues even though rooftop farming is still not a common sight in Singapore. Singapore’s first commercial aquaponic rooftop farm on the top of the *SCAPE building in Orchard is run by Comcrop (a social enterprise). They supply vegetables and herbs to F&B outlets and hotels nearby which has significantly minimized carbon footprint. This initiative has been a success every since its implementation.


Fig 1. First commercial rooftop garden in Singapore. (Photocredit : Nicole Poi)

18Fig 2. Wide variety of tomatoes were planted from heirloom tomatoes to cherry tomatoes.

(Photocredit: Nicole Poi)

What are your thoughts about rooftop gardening? Do you think that it is sustainable and worth the effort?


Potential of high-rise greenery

In the past decade, we have seen the rise of high-rise greenery in Singapore. A new target of achieving 200ha of high-rise greenery by 2030 was set in 2014 after the previous target of 50ha by 2030 was met two decades earlier. As of 2014, Singapore has 61ha of greenery covering the exterior of the buildings; one of the highest among cities in the world. This huge increase could be due to the Skyrise Greenery Incentive Scheme (SGIS). Under the SGIS, NParks will fund up to 50% of the installation costs of rooftop greenery and vertical greenery.

Green roofs and vertical greening improves the thermal performance of the building, saving energy needed for air-conditioning. This is especially significant in Singapore given our climate. In addition, green roofs help with storm water discharge control, reduce noise pollution, improving air quality and reducing the urban heat island! With more buildings having vertical greenery coming up, I wonder about the potential for fauna among such urban greenery and its potential to be used as biodiversity corridors or stepping stones that allow connectivity between different urban parks and nature areas in Singapore. Would developers/building tenants choose to not attract biodiversity (or actively getting rid of them) as it would add to the maintenance cost of the green roof/wall making it sub optimal to plant? After all, I think the vertical greenery is mainly planted due to its attractiveness and for its properties of cooling the building.

Do contribute your thoughts and any possible ideas for improving connectivity through green roofs/walls!



Paradise tree snake, a successful reptile in urban area?

This blog is inspired by Sherry’s post on S12 “mini-forest”. I recalled my encounter with a Paradise tree snake, or Paradise flying snake (Chrysopelea paradisi) near that patch of forest. I was a little bit surprised as the place is no way near a natural reserve or a park.



The IUCN Red List classify them as Least Concern:

Listed as Least Concern in view of its wide distribution, presumed large population, it occurs in a number of protected areas, is tolerant of a degree of habitat modification, exists as an apparently stable population, and is not subject to any major threats.

They appear to be urban adapters as they can inhabit a wide range of urbanized habitats.

It has been recorded from coconut plantations adjacent to forests, rural villages, tree-shaded gardens, and within the attics of old houses.

They are also widespread in Singapore.

Commonly encountered in a variety of habitats including mangrove, secondary forest, and parks and gardens.


From previous lectures we learned that reptiles are heavily impacted by urbanization because of their low mobility, ground-dwelling nature and so on, yet there are still abundant Paradise tree snakes in the heavily urbanized Singapore. Are there any properties that make them successful? Here are my speculations:


  1. The ability to “fly”
    Snakes in this genus perform parachute jump, giving them the name of “flying snakes”. Their bodies form a concave surface that acts like a parachute, and therefore prolong the “flight”.   They generally move from tree to tree, but sometimes land on the ground. This greatly increase their mobility in terms of distance and speed, and perhaps the ability to cross gaps. This could potentially justify their presence in habitats with relatively fragmented canopy cover, such as parks.
  2. Arboreal nature
    They usually live in tree canopies and rarely land on the ground. This greatly reduce their encounter with humans as well as the frequency of road kill. In addition, Singapore as a garden city provides more canopy cover as their potential habitats compared to most cities.
  3. Favouring coconut palms
    Their favorite habitat seem to be the crown of coconut palms. Fortunately, there are plenty of coconut palms in Singapore.
  4. Lizard-hunters
    Their diet mainly consists of tree-dwelling lizards, which are abundant in Singapore. They also eat rodents, frogs and birds. Compared to snakes that prey on larger animals (e.g. King Cobra prey on other snakes; adult reticulated pythons prey on mammals and birds), their is more food available for Paradise tree snakes in Singapore.
  5. Mild venom
    Their venom is mild and harmless to human. Although many residents still find it terrifying, there is usually not a need to eliminate Paradise tree snakes despite their abundance in city.


It seems that Paradise tree snakes have many traits that make them successful in Singapore, perhaps also other tropical cities. However, these five points are far from complete. I would love to know your thoughts on this.

We can further look at other snakes abundant in cities to study their common traits. Here is a website on snake encounters:




Exploring possible luxury effect in Singapore


Luxury effect refers to the positive correlation between urban canopy cover and wealth of the neighbourhood [1] [2]. In some context, the concept is also applied to plant diversity [3] or even animal diversity (e.g. birds [4] and lizards [5]).

It got me curious about whether or not there is a similar pattern in Singapore. Without looking at the data, there can be very different predictions:

  1. No, there isn’t, because plants in Singapore are managed by the governments rather than the residents.
  2. Yes, there is, because wealthier people likes to live near vegetated areas. (e.g. Condominiums are mostly near natural reserves.)

Therefore, I explored the possible luxury effect in Singapore by comparing vegetation cover and monthly income of 35 planning area. I used ArcGIS, Excel and R as my analysis tools. Now I will show you the detailed methods that I used.

Methods and Results

Step 1: Mapping income data

The source of income data is Census of Population 2010. Population from each monthly income level was reported for 35 planning areas. The other 20 areas were not reported possibly because of small population.


I then calculated the mode, median, and average income for each planning area and typed the information into a map consisting of all planning areas. The map for planning area boundary was retrieved from The following map presents median of income in each area. I changed the symbology so that the darker the red color is, the wealthier the area is. Areas without data has no color.



Step 2: Land cover type classification

I used a satellite image exported from The good thing about cartodb is that I can export map with a pretty high resolution (2400 *2400 in this case).


I clipped out Singapore using the boundary of planning areas.


Using the Image Classification tool, I was able to perform interactive supervised classification on the satellite image. In other words, I picked some typical samples of vegetation, waterbody and non-vegetated area to train ArcGIS, and then ArcGIS identified the class for the rest of the map.

Here are the training samples I chose. I feel that the training samples can be improved, because I doubt it can classify southern Singapore very accurately. Please give me some suggestions if you know how to improve it!


Here is the result of classification. Green represents vegetation, blue represents waterbody, and beige represents non-vegetated areas.


I converted this raster layer into a vector layer for further analysis.



Step 3: Visual comparison

Let’s overlay the Income Layer and Land Cover Type layer from Step 1 and 2.


With the Effects toolbar in ArcGIS you can swipe the top layer to compare. You may observe that some of the wealthiest areas, such as Tanglin, Bukit Timah, and Mandai have pretty high proportion of vegetation. However, visual comparison is not enough.


Step 4: Intersection

I did an intersection of Income and Land Cover Type layers, in other words, identifying all patches of vegetation, waterbody, and non-vegetated area in all planning areas.


I used the Summary Statistics tool to sum up the total area of the three land cover types in all planning areas. I obtained the following output table.


I exported this table to Excel and processed the data further there.


Step 5: Linear regression

I plotted the percentage of vegetated in total area (waterbodies subtracted) against mode, median, and average monthly income. The subtraction of waterbodies actually didn’t make a great difference to the results, but I did it so that the data makes more sense.





As you can see, there are very slight positive correlations between vegetation and income in all three cases, but unfortunately, all correlations are non-significant (p>0.05).



Does this mean that the luxury effect does not hold in Singapore? Not necessarily, I would say. There are still some more factors to consider.

1 Boundary and scale

I looked at the top five areas with highest percentage of vegetation:

  1. Mandai
  2. BukitPanjang
  3. BukitBatok
  4. Tanglin
  5. Yishun

Bukit Panjang and Yishun had high vegetation cover but low income. However, residents most likely do not live in the large patches of vegetation. We need to take note that:

When it comes to ecology, political boundaries are often not meaningful.

The inclusion of large patches of vegetation in these planning areas might mask the real pattern. Instead of planning areas, neighbourhoods together with buffer zones around them may be better units of analysis, so that we can exclude the non-habitable areas.

However, income data for neighbourhoods is not available, so I decided to take another approach: looking at the locations of private landed properties, as private landed properties are usually associated with high income. We can potentially use condominiums and HDBs, as condominiums are generally more expensive than HDB, but there is not a good map for condominiums.

I retrived a map for private landed properties from URA website: Landed Properties

I overlaid it on Land Cover Type layer.


I noticed that for Bukit Panjang and Yishun, rich people still live near natural reserve. This map also showed us:

Scale is important in spatial ecology.

We can get more useful information by zooming into neighbourhoods.

2 Preference for housing location

I also looked at the top five areas with lowest percentage of vegetation:

  1. Singapore River
  2. Geylang
  3. Rochor
  4. River Valley
  5. Downtown Core

I noticed that apart from Geylang, all the other areas are near Singapore River, or Singapore’s CDB. This is contradictory to the prediction from luxury effect, but again, more study needs to be done on the scale of neighborhoods.

Unlike North American cities where better residences are at the outer zone of the city, wealthy residents’ preference for housing location in Singapore shows two extremes: near natural reserves (high percentage of vegetation), or near Singapore River (low percentage of vegetation).  This difference, together with the fact that most plants are not managed by residents, might explain why luxury effect does not hold true in Singapore.

3 Limitation

A limitation of this study is that income data was given in categories, so that I had to designate a value to each income level, which may reduce the accuracy. In addition, most of the areas have a median income between 2500-3999 SGD, represented by only two income levels. Having more income levels will give us more information.

Canopy cover could potentially be measured on a finer scale, with a satellite image of higher resolution. The type of vegetation and diversity of plants could be studied with field work.



The luxury effect is not observed in Singapore on the scale of planning areas. However, study on neighbourhood scale is needed to confirm.



Although income data is not available on neighbourhood scale, I think we can use housing type as a proxy. That would require us to produce a map with all resident areas and corresponding housing type in Singapore. That is a lot of work. SLA actually has a map for this: They sell it for 100 SGD. I and my friends have asked SLA and they responded that NUS has paid for it, but I have not been able to obtain it yet.



[1] Zhu, P., & Zhang, Y. (2008). Demand for urban forests in United States cities. Landscape and urban planning, 84(3), 293-300.

[2] Schwarz, K., Fragkias, M., Boone, C. G., Zhou, W., McHale, M., Grove, J. M., O’Neil-Dunne, J., McFadden, J. P., Buckley, G. L., Childers, D., & Ogden, L. (2015). Trees grow on money: urban tree canopy cover and environmental justice. PloS one, 10(4), e0122051.

[3] Hope, Diane, Corinna Gries, Weixing Zhu, William F. Fagan, Charles L. Redman, Nancy B. Grimm, Amy L. Nelson, Chris Martin, and Ann Kinzig. “Socioeconomics drive urban plant diversity.” Proceedings of the national academy of sciences 100, no. 15 (2003): 8788-8792.

[4] Lerman, S. B., & Warren, P. S. (2011). The conservation value of residential yards: linking birds and people. Ecological Applications, 21(4), 1327-1339.

[5] Ackley, J. W., Wu, J., Angilletta, M. J., Myint, S. W., & Sullivan, B. (2015). Rich lizards: How affluence and land cover influence the diversity and abundance of desert reptiles persisting in an urban landscape. Biological Conservation, 182, 87-92.


Further links and useful readings

Lizards in Phoenix:

The Luxury Effect

Urbanization and plant diversity:

Walker, J. S., Grimm, N. B., Briggs, J. M., Gries, C., & Dugan, L. (2009). Effects of urbanization on plant species diversity in central Arizona.Frontiers in Ecology and the Environment, 7(9), 465-470.

Map of HDBs:

Map of condominiums:

A step in the right direction?

As a member of the Green Party of Canada, I receive occasional updates on my FB page. This morning, it was a shared link to an article about the conversion of a decommissioned coal-fired power plant in Ontario to a solar farm. My initial reaction was “looks like a step in the right direction”. And it may well be one. After all, burning coal is the dirtiest way to generate electricity. But I’m left with two big questions. First, how much electricity will this solar farm generate (as in the percentage of the original capacity of the coal-fired plant)? Here, I’m thinking about land-use. Second, considering that cradle-to-grave analysis of solar energy production reveals some negative environmental impacts, especially related to the production of panels (which uses rare-earth metals and some pretty nasty chemicals) and their eventual disposal, what are the downsides of going this route? I don’t mean to denigrate clean technologies – I am supportive of developing solar, wind and geothermal power generation – but I can’t help thinking that there should be at least as much, if not more, emphasis placed on reduction of demand as there is on implementation of alternative sources of energy. Why doesn’t the Green Party and, for that matter, the Government of Canada (well, why not all governments?) really starting pushing urban populations to reduce consumption?

All abuzz about bees

In yesterday’s lecture, we had the privilege of listening to Dr John Ascher share more about bees in the city. Of all the new information gleaned, perhaps the most relevant one – to daily life, that is – we learnt was how to differentiate between a wasp and a bee: bees are usually [1] hairy, with broad hind legs and a tongue for sipping nectar, all of which wasps lack. Because most people are unable to tell the difference, bees are often misrepresented as dangerous creatures when in fact, it is wasps that are much more aggressive and lethal [2] – as natural predators, their streamlined bodies allow them to attack at much greater speeds and sting their prey multiple times, whereas bees are much slower and die after stinging once.


This Greater Banded Hornet (a social wasp) is the deadly one! (Photographed by Eddie Tan, 2012 )

The giant honey bee, Apis dorsata, also has a deadly sting (if you’re allergic), but don’t worry, it lives in the treetops so you’re not likely to spot it! (Photographed by Zestin Soh, in (Soh & Ngiam, 2013))

The giant honey bee, Apis dorsata, also has a deadly sting (if you’re allergic), but don’t worry, it lives in the treetops so you’re not likely to spot it! (Photographed by Zestin Soh, in (Soh & Ngiam, 2013 [3])

Most bees we see in urban parks and gardens, unlike the giant honeybee (pictured above), are actually non-aggressive and also non-venomous [4]. Thus, there is actually no need to run away screaming whenever we see or hear that familiar buzzing sound – unless, of course, you think you’ve met a hornet, then by all means please do run! [5]

On a more serious note, we also learnt why cities are important habitats for bees – they serve as a refuge from agricultural pesticides, mammalian megafauna and droughts, especially in cities located in drier climates. In our own tropical garden city, bees are in fact more commonly found in rooftop gardens. This is because they are unable to thrive in heavily manicured ground-level vegetation, which often grow in compact soil that are not suitable nesting sites for ground-nesters. As early successional colonizers, bees prefer habitats that have weeds and shrubs, which provide good shelter and food resources.

Following Dr Ascher’s lecture, we had a hands-on activity whereby we were given datasets on Singapore bees, which were then mapped out using this really cool online mapping tool and analyzed. After playing around with the tabs and trying to figure out how things worked, I managed to map out the distribution of Hylaeus sp.

Hylaeus sp. (photographed by Zestin Soh, in (Soh & Ngiam, 2013))

Hylaeus sp. (photographed by Zestin Soh, in (Soh & Ngiam, 2013 [3])

Map of Singapore showing the distribution and density of Hylaeus sp. (Created using Cartodb)

Map of Singapore showing the distribution and density of Hylaeus sp. (Created using Cartodb)

At first glance, the distribution of Hylaeus sp is concentrated in the southern part of Singapore, though they are present in other parts of the city as well. Given that Hylaeus sp is found in a variety of green areas [6], they are likely to be urban adapters. This means that they are able to live opportunistically in close proximity to humans. Urban adapters are usually generalists – they aren’t picky about their meals, unlike specialists – and are able to live in altered habitats or patches. Thus, they are likely to be found in a range of urbanization gradients, which is what we see for Hylaeus sp.

However, upon closer look at the data, I realized that 1 sighting was recorded on 1876 while the rest were dated from 1972 to 1978. Hence, it is likely that the urban structure of Singapore has changed quite substantially since then (especially for the 19th century record) and the distribution seen on the map above may be misleading. To properly analyze the occurrence and habitat of Hylaeus sp, we would then need to refer to older maps of Singapore and match those with the data.

Still, based on the datasheet, we do know that Hylaeus sp is a native species and a cavity-nester. Thus, it is unsurprising that they are able to adapt well to urban environments, since man-made structures such as sidewalk or building cracks could very well serve as a home for these little creatures.

What do you guys think?


[1] Do note that there are always exceptions in nature!

[2] That is, if you happen to have an allergic reaction to its sting

[3] Soh, Z. W. W., & Ngiam, R. W. J. (2013). Flower-visiting bees and wasps in Singapore Parks (Insecta: Hymenoptera). Nature in Singapore6, 153-172.

[4] some don’t even have stings!

[5] Perhaps this would be a good time to brush up your knowledge of the 3 hornets we have in Singapore.

[6] They seem to be able to survive in urban parks, forests, and mangroves

The mini Blk S12 “forest”

Back in those days when I was in Year 1/ 2, most of my lectures started at 10 a.m. and were held at LT32. Once in a while my friend would be late for class and so at 10.05 a.m., I would text her to ask her where she is and she would reply, “climbing the LT32 mountain!!” Ten minutes into the lecture, she would appear at the door then make her way towards her seat next to me, panting. To most of us who have had lessons at LT32, it is probably intuitive to us that my friend’s “LT32 mountain” refers to the laborious “hike” up the slope along Science Drive 4, and then up again the long flight of stairs that would eventually lead us to the carpark behind LT32.

For the past coming to 4 years in NUS, I’ve “hiked” that path umpteen times. Along the way, once in a while I would slow down just to spend a couple more minutes enjoying the vegetation on the left of the walkway, i.e., this:

(that's Blk S12 in the background)

(that’s Blk S12 in the background)

To most of us who started started studying in NUS only 3 to 4 years ago, perhaps this patch of vegetation seems just like any other “garden” or “park” in the middle of a built-up area. Me too, until a year ago when I learnt from my then UROPS (and current FYP) supervisor how this space was greened up.

Unfortunately, I was unsuccessful in sourcing for photos of the area before it was greened up, but here’s how it looked like on Google Earth:

Satellite image in 2010

Satellite image in 2010.

We can see that it was still a very bare area with hardly any green cover six years ago in 2010 (the triangular patch in the middle of the photo). But today, the same patch is thriving and growing so well with NATIVE SPECIES. Yes, species that are native to Singapore. Theoretically speaking, planting native flora may support greater local wildlife. I wanted to experience for myself how this patch of native green cover has attracted native wildlife in our NUS campus and so I spent a short one hour at the area. To my pleasant surprise, my eyes were treated to a feast! Here are some of the fauna and flora I found:

Spotted Dove (Streptopelia chinensis)

Spotted Dove (Streptopelia chinensis)

This gentle dove was happily feeding on the ground before it flew to this concrete ledge, seemingly aware I was snapping photos of it.

Pink-necked Green Pigeon (Treron vernans)

A pair of pink-necked Green Pigeons (Treron vernans)

These two love birds were comfortably roosting high up in the tree canopy. The male pigeon (left) looks much more colourful with pink nape and neck, and orange covering the lower breast area, while the female (right) is largely covered in a green coat.

Plantain squirrel (Callosciurus notatus)

Plantain squirrel (Callosciurus notatus)

The playful squirrel was foraging for food for a good 10 to 15 minutes, running up and down the treelets and across the ground, and I managed to snap this shot (still slightly blur though) after several failed attempts.

Unknown bird with orange beak

Unknown bird with orange beak

I’m not sure what species this is, but it could be a lineated barbet ( I’m just guessing though.

Silhouette of another unknown bird

Silhouette of unknown bird 2

Silhouette of unknown bird 3

Silhouette of unknown bird 3 (it could be a dove based on it’s horizontal posture)

The call of a Collared Kingfisher (Todiramphus chloris) (it’s a bit soft, please try to increase the volume level of your computer!)

Our all time (not so) favourite, the  Javan Myna (Acridotheres javanicus)

Our all time (not so) favourite, the Javan Myna (Acridotheres javanicus)

I also saw quite a few Weaver Ants' (Oecophylla smaragdina) nests

I also saw quite a few Weaver Ants’ (Oecophylla smaragdina) nests.

In particular, insects are an interesting one because they form the lower tropic levels and may underpin food webs, thus supporting more charismatic species at higher trophic interactions. But the most important of all is of course the plants, which is the basis on which all life is based. Just to share some of the beautiful flora that can be found in this patch of native green area!

Blue Strawberry Flowers (Memecylon caeruleum)

Blue Strawberry Flowers (Memecylon caeruleum)

Peach-pinkish coloured fruits of Memecylon caeruleum

Peachy-pinkish coloured fruits of Memecylon caeruleum

False Lime (Suregada multiflora)

False Lime (Suregada multiflora) flowers (not freshly blossomed ones though)

Fruits of Suregada multiflora

Fruits of Suregada multiflora. They do look similar to our “normal” lime!

Sometimes when this plant (Suregada multiflora) is producing lots of flowers, it’ll be easy to pick up a very slight fragrance that whiffs past when the wind blows. This is a critically endangered species and one whole row of it is planted just next to the brick walkway.

Wild Pepper (Piper sarmentosum)

Wild Pepper (Piper sarmentosum)

Im not sure what species this is

Im not sure what species this is, but it sure does look elegant!

Nibung Palm (Oncosperma tigillarium)

Nibung Palm (Oncosperma tigillarium)

These three palms are probably the most conspicuous plants as they are “sticking out” of the entire patch. In fact, several species of back mangroves/ mangrove associates/ swamp-adapted species were planted at the bottom of the slope because of the more water-logged conditions below. These include:

Mangrove Fan Palm (Licuala spinosa)

Mangrove Fan Palm (Licuala spinosa)

I’m not 100% certain of this species ID, but it does seem like it, from the bright orange fruits!

Pandanus spp.

Pandanus spp.

My conclusion at the end of my mini field trip was that there is so much biodiversity in the area! This is a good example to illustrate how urban biodiversity can be enhanced by providing (or planting) species’ habitats. Plus, an added bonus is that most of the plants in the area are native, some of which are locally threatened, e.g., the Nibung palm and False Lime, and thus this helps in the conservation of local species as well. While urbanisation has inevitably led to the loss of natural habitats and human-wildlife conflicts, I guess we can still make the best out of a not-so-good thing (e.g., by creating artificial habitats for organisms and still try to attract fauna into our urbanised areas). I will illustrate this using the following two examples:

This huge exotic rain tree is being navitised by the native Hoya spp. that is climbing on it

This huge exotic rain tree is being navitised by the native Hoya spp. that is climbing on it!

Wild Pepper seedlings growing at the shady areas below larger shrubs and trees

Wild Pepper seedlings growing below larger shrubs and trees. Where space is a constraint, plants can be cultivated at different layers so as to increase the number of plants per unit area!


Who would have known? Everyday we walk in and out of our campus not knowing that all these beautiful flora and fauna exist just right at our doorstep! Of course, as an amateur, I’ve probably only scratched the surface of the much more diverse and rich urban biodiversity we have in NUS, as well as the rest of Singapore, but this only goes to show that while we can’t “un-urbanise” an area, or “un-plant” exotic species, or undo the damages already done, we still can work around the situation and make the best out of it!

(all photographs were taken by me)