Book highlights: “Dynamic Environments of Singapore”

I borrowed a book called “Dynamic Environments of Singapore” by Daniel Friess and Grahame Oliver (published in 2015) from a public library recently, which I find quite informative, though slightly dense.

Here’s sharing some noteworthy details:

1. The oldest dated rock in Singapore is the Gombak Gabbro (260 million years old, +/- 2 million years).
2. Singapore is situated at the southern terminus of the Indosinian Mountain Belt formed around 220 to 200 million years ago.
3. Bukit Mandai, Bukit Batok and Bukit Timah are made of igneous rocks such as Bukit Timah Granite and Gombak Gabbro. These hills above 100 m form the highest relief in Singapore.
4. Slope failure in Singapore often occurs during the wet monsoon period on steep topography, where the forest has been removed and where slopes have been engineered for building purposes (e.g. slope failure at Mount Faber in June 2013).
5. Though Singapore barely has any agriculture, soils are essential to support vegetation growth in the green areas (e.g. Central Catchment, nature reserves, parks, gardens, open green areas) and to sequester carbon.
6. Mudflats are a rare habitat type in Singapore, with one of the best examples found in northwest Singapore, fronting Mandai Mangrove. This is a key habitat for the endangered Mangrove Horseshoe Crab.
7. Singapore’s subtidal habitats are threatened by local changes in biophysical conditions, such as reclamation and dredging, as well as regional and global-scale changes such as ocean acidification.
8. Some species, especially mammals, have large home ranges, and each individual requires a minimum area of habitat to support a viable population. If a habitat patch is smaller than this minimum area, local extinctions may occur.
9. In July 2013, The Straits Times reported that almost 360 macaques (20% of the national population) were culled in the first 6 months of the year in response to complaints by residents…. Sha et al. (2009) recommended better land use planning (e.g. leaving a forest buffer zone instead of developing right up to the boundary of the Nature Reserve) and increased public education to manage potential human-macaque conflict.
10. Singapore’s habitats are extremely patchy and fragmented. A number of actions can be taken to address this. Firstly, existing habitat fragments should be protected under law to ban new development and reduce further fragmentation. Secondly, developed areas could be converted back to natural habitats through habitat restoration. This option would increase the size of current habitat patches, reducing the impact of edge effects. If planned correctly, it could also improve the connectivity of current habitat patches.
11. Green space provision utilises the biophysical watershed protection value of green spaces (e.g. filtration – water quality) and the interception and infiltration benefits of green spaces (water quantity).
12. If we effectively incorporate green spaces into building and land use planning, we may be able to reduce surface air temperatures and energy demand (from air-conditioning). This should not be purely seen as a gardening project; we need a concerted effort to understand and attempt to replicate the biophysical functions of green spaces.
13. Species endemic to Singapore include the Singapore Whiskered Bat and the Singapore Freshwater Crab, a critically endangered crab species only discovered in 1986, and only found in streams near Bukit Timah and Bukit Gombak. These species are at great risk of extinction as they are found exclusively in Singapore and nowhere else.

Which of these points stands out for you the most?

Igneous rocks at Little Guilin, Bukit Gombak, Singapore

For me, the first two points particularly stand out because they remind me that the Singapore story can be told through the rocks.

For example, the story of Singapore began millions of years ago when the island was formerly part of a huge landmass before plate tectonic forces, sea level changes, weathering and erosion etc shaped it to its present state, where anthropogenic factors have recently been making dynamic changes in the past couple of centuries as well.

Screenshot of a page about how the urban heat island effect is offset by the cooling effect of green spaces, such as Tengah forest, in Singapore

P.S. On a similar note, SG Climate Rally is co-organising an event called Deep Time Walk this coming Sunday (17 March 2024). If you are interested, please click here for more information.

P.P.S. My debut poetry book “Nature Sketch: A poem about the Twelve Apostles in Victoria, Australia” is about ancient rocks too. Feel free to check it out here.

Beach cleanup at Sungei Durian, Pulau Ubin (24 February 2024)

Nature and us are inseparable – this truism becomes evident as we venture into the wild and participate in environmental stewardship.

Last month, the Pulau Ubin cleanup session was postponed due to inclement weather during the northeast monsoon season.

Thankfully, the weather was dry when we embarked on our first beach cleanup session of the year 2024 yesterday, albeit a tad too hot and humid in the mid afternoon, causing us to perspire even before we started picking up litter in the vicinity of Sungei Durian near Kelichap Hut on the eastern side of the island.

Despite our small number (only nine of us volunteers turned up), we managed to collect a sizable amount of waste items, which weighed a total of 95 kg!

Some of the discarded engines that were washed ashore were too bulky and heavy for us to carry back to the hut for proper disposal.

I was heartened to see a number of slender mudskippers (Periophthalmus gracilis), aka graceful mudskippers, at the mouth of Durian River which flows into the sea. As potential bio-indicators of heavy metal pollution, their presence suggests a fairly healthy ecosystem despite the apparent pervasiveness of pollutants in the water.

A slender mudskipper (Periophthalmus gracilis), whose conservation status in Singapore is vulnerable

The mangroves and mudflats of Sungei Durian were exposed at low tide that afternoon.

The types of waste that we have collected include plastic tubes, plastic bottles, plastic food packaging wrappers, shoes and slippers, broken glasses, fishing nets, cloths, lighters, batteries, pulley, engines, tire inner tubes, straws, boat fabrics, electrical wires, plastic utensils, PVC floor carpets and metal cans.

Kudos to the event organiser Joseph Tan and my fellow volunteers for the great teamwork and efforts in making the natural environment cleaner and more habitable for the inhabitants.

Here’s to our dedication in keeping our islands clean. (Group photo by Joseph Tan)

P.S. If you would like to take part in the future Pulau Ubin cleanup activities, please follow the event website here to stay updated on the upcoming sessions.

Sungei Buloh wetland reserve: 30th Anniversary | World Wetlands Day celebration with Biking 4 Biodiversity

On 25 November 2023, I attended the celebration of the 30th anniversary of Sungei Buloh wetland reserve at the main visitor centre.

Excerpt of a speech about the history of Sungei Buloh Wetland Reserve, Singapore. The speech was delivered by Mr Desmond Lee, Minister for National Development and Minister-in-charge of Social Services Integration.

Sungei Buloh has gone from strength to strength, and has been transformed from glory to glory since its inception in 1993, thanks to conservation efforts by Nature Society (Singapore) and volunteers among the general public.

Even as Singapore aims to become a metropolis, the few remaining mudflats are gaining ground in nature education and conservation.

Increasingly, Nature is being recognised for providing exemplary solutions to climate change, such as sequestering carbon, combating sea level rises, and cooling the urban heat island effect.

Hence, to buffer the mangrove habitat at Sungei Buloh, key wetlands such as Kranji marshes, Kranji coastal park, Mandai mangroves and mudflats, and Lim Chu Kang nature park have been designated by NParks for ecological connectivity and biodiversity protection.

White-bellied sea eagles, smooth-coated otters and other wildlife have been observed to roam Mandai mangroves and mudflats as their feeding ground. Since the eagles usually roost on Albizia trees, it is important to protect the forest fragment along Kranji north original alignment of the green corridor from the proposed redevelopment of Kranji water reclamation plant. The projected increase in effluents from the future redeveloped water reclamation plant may also affect marine life, since most of the culverts in the Johor-Singapore causeway are reportedly damaged and result in stagnation of sea current flows.

It is likely that fishes mainly congregate near the mangroves instead of the causeway, since the damaged culverts might have resulted in water stagnation and toxin buildup in the immediate vicinity.

On 6 February 2024, in celebration of World Wetlands Day (2 February), I had the pleasure of hiking with cyclists-cum-biologists Hanna Öllös and Jonas Sommer from Biking For Biodiversity (B4B) in Sungei Buloh wetland reserve and the periphery of Mandai Mangroves and Mudflats nature park, with Nanyang Technological University lecturer Dr Sng Bee Bee as our guide.

We were blessed to see a number of interesting wildlife, including a critically endangered estuarine crocodile, a milky stork, an uncommon green crested lizard and water monitor lizards.

Plantain squirrel

Garden orb weaver spider

Short-nosed fruit bat

Lesser adjutant

Malayan water monitor lizard

Grey heron

Purple heron

Saltwater crocodile

Great-billed heron

Harlequin butterfly

Dragonflies (common scarlet)

Yellow-barred flutterer

Rufous-legged grasshopper

Milky stork

Milky stork

Green crested lizard

Scaly-breasted munia

Thai vinegar crab

Snapshot of the rich biodiversity of Sungei Buloh wetland reserve and Mandai mangroves & mudflats, as seen on 6 February 2024, some with the help of my fellow hikers.

Interestingly, the “blueberry jam lookalike” poop of a palm civet (aka musang) was found near Musang Hut in Sungei Buloh wetlands reserve extension. Among their ecological roles, these nocturnal mammals serve as seed dispersers, as they eat fruits of plants, such as fish-tail palms.

In our conversations, we talked about how natural habitats and biodiversity have been lost over the decades, how housing can be built on previously developed lands instead of forested areas, and why the “infinite growth” economic model needs to transition into a more sustainable and equitable economic model, such as degrowth (or post-growth) or doughnut economic model that respects ecological and social well-being.

In the evening, both Hanna and Jonas shared their experiences of learning about how local people tackle nature conservation issues, which they became aware of while cycling through various countries in Europe and Asia.

During the talk, the participants had an open discussion on nature conservation issues, which include:

1. Animal tourism (welfare of animals in captivity)
2. Illegal wildlife trade (implications on rehabilitation/rewilding of rescued animals that are habituated to the human environment)
3. Habitat loss and fragmentation (implications on human-wildlife conflicts and endangerment of rare animals)
4. How Singapore can contribute to nature conservation across Southeast Asia

Regarding the question on how Singapore can contribute to nature conservation across Southeast Asia, I think it’s about cultivating awareness among as many people as possible. Out of that awareness, people’s attitudes and behaviours can be changed eventually.

Rescue of an injured waterhen at West Coast Vale

On 9 January 2024, I was involved in the rescue of an injured bird, which I passed by around 7.30 pm while cycling along West Coast Vale during my dinner shift.

After stopping to examine the stationary body of the bird in the middle of the road, I recognised it was a white-breasted waterhen and initially thought it was dead as it wasn’t moving and its eyes were closed, even as a car passed by next to us.

However, when I prepared to scoop up its body using a plastic bag as a makeshift glove, the bird opened its eyes at my touch.

I gingerly carried the waterhen to the roadside and contacted ACRES (Animal Concerns Research & Education Society) via WhatsApp to request for rescue.

ACRES advised me to call NParks (National Parks Board) instead, as their rescue centre has reached maximum capacity for injured animals.

So I called NParks Animal Response Centre, and their representative asked me to send photos and videos to them via WhatsApp, which I did.

Then another NParks representative called me to inform me that a contractor has been dispatched to collect the waterhen.

She also wanted to confirm if the waterhen was still alive since one of the photos I sent to them showed the waterhen with its eyes closed, and she asked me to contact them if the waterhen happened to die before the contractor arrived.

While waiting for the contractor to arrive, I observed the waterhen who appeared to be in pain as it closed its eyes intermittently.

I spoke words of comfort to the waterhen, assuring it that all would be well.

About half an hour later, the contractor’s van arrived on the scene, and the waterhen flapped its wings as if sensing that help was coming.

After examining its legs, which appeared limp, the contractor gently placed the waterhen in a cage to be transported safely for treatment.

Locations of various sightings of white-breasted waterhens at West Coast Vale and around Sungei Pandan (Source: iNaturalist)

Come to think of it, West Coast Vale is a dangerous zone for wildlife crossings because it was located between two green spaces inhabited by wildlife such as birds and reptiles.

Over the past year or so, while doing my delivery shifts, I have come across other roadkills, such as snakes and lizards, along this road where cars tend to travel at high speed.

Monitor lizard roadkill seen along West Coast Vale on 30 September 2023. This, together with other such roadkills that I chanced upon, has been reported to the Herpetological Society of Singapore for their records.

Maybe having culverts (for safe wildlife crossings), speed bumps/humps and animal crossing signs to alert drivers can help prevent or reduce accidents involving wildlife?

Impact of deforestation and urbanisation on parakeets and mynahs in Singapore

Fringe of a forest fragment in Tengah Forest East

Long-tailed parakeets

Red-breasted parakeets

Javan mynahs

Much like humans and other primates, certain bird species such as parakeets and mynahs are social creatures.

Towards end of the day, parakeets and mynahs would flock to their roosting trees to congregate, chat/chatter loudly to exchange notes and greetings before retiring to bed.

One difference is that parakeets are forest-dependent birds and prefer to roost in the woods, while mynahs are urban-adaptative and prefer to roost in trees in residential or industrial areas.

Long-tailed parakeets seen briefly at the fringe of Tengah Forest East on 1 January 2024, which has been partially cleared to make way for housing.

Javan mynahs flocking to a tree in Potong Pasir housing estate in the evening on 10 October 2021

However, as regenerating secondary rainforests, such as Tengah forest, dwindle over the years, the displaced parakeets have to roost along the forest fringe or find new homes in other forests (where they may have to compete for living space with the existing wildlife residents).

One limitation of forest fringes is that they are exposed to light pollution from the roads and buildings nearby.

Hence, some parakeets are forced to adapt to roosting in trees in residential areas nearby, such as Choa Chu Kang, perhaps as an interim stopover until they can find a more permanent home.

However, these parakeets have to jostle for space with mynahs and other urban-adaptative birds, such as crows and pigeons (especially since roadside trees are relatively few and are often heavily pruned).

Long-tailed parakeets and red-breasted parakeets hanging on a bare tree in Choa Chu Kang housing estate in August 2023 (Photo by James Teiw)

Moreover, the parakeets’ loud calls may not be welcomed by some human residents in the neighbourhood.

Sadly, many of these parakeets were captured for culling by the authorities who responded to complaints by residents in recent years.

The native long-tailed parakeets have been captured together with the non-native red-breasted parakeets, and the latter were put to death for being seen as “invasive”, “noisy” and “competing with the native long-tailed parakeets”.

Regardless of whether the red-breasted parakeets are responsible for endangering the survival of the long-tailed parakeets, it is clear that habitat loss and fragmentation have contributed to their population decline, such that they are now nationally vulnerable.

The red-breasted parakeets are globally near-threatened, but they seem to be better adapted to urban environments than the indigenous long-tailed parakeets in Singapore.

Now that the facts are clearly established and the knowledge of science is made known to everyone, any further deforestation resulting in further reduction in the population of long-tailed parakeets (as they inch towards extinction) — or any further culling of red-breasted parakeets through no fault of their own for that matter — would be tantamount to pre-meditated murder or structural genocide or ecocide.

“There has been no direct evidence demonstrating the negative impact of the red-breasted parakeets in Singapore’s ecosystem. These birds favour open good spaces in Singapore instead of mature secondary forests such as those in the Central Catchment Nature Reserve and are hence generally away from sites where most of Singapore’s endangered resident birds reside.”

From “Commentary: Should we be worried about mandarin ducks and parakeets squeezing out Singapore’s native birds?” (CNA, 17 September 2023)

Bukit Batok hillside park: Water pollution of rare natural freshwater stream caused by silty runoff from construction site

The stream flowing from the source near the well in the central vale of Bukit Batok hillside park on 28 November 2023 was clear until it flowed downstream past the round water tank near a construction site.

While I was checking out the cascades of the natural freshwater stream (indicated as Stream A in the Bukit Batok hillside park EIS report) during a storm on Tuesday 28 November 2023 around 4 pm, I noticed that the originally clear water of the stream was eventually mixed with the muddy storm runoff flowing from the West Hill BTO (Build To Order) construction site towards the pond downstream.

I wonder how the native wildlife, such as dragonflies, damselflies and the uncommon copper-cheeked frogs, will be affected, which are found along this rare natural freshwater stream in this ecologically sensitive ecosystem, which is located near the construction site.

Please refer to the video below for reference.

Some members of the Nature community are also concerned about the environmental impacts of the stream pollution.

One of them commented that the wildlife that depended on the stream would die.

Another wrote “Looks like a failure of their ECM. HDB needs to be informed.”

As noted on page 79 of Bukit Batok EMMP (Environmental Mitigation and Monitoring Plan) report:

“Stream A and Stream B should be preserved as much as possible, or at least Stream A, as they are a couple of forest-dependent frog species. The stream can be retained as natural water features within the housing area. Some vegetation along the stream should also be retained as habitat for the frogs. Gentle slope and earth retaining measures such as geotextile should be designed along the remaining stream if it is remained”.

In my report via Life SG app on 2 December 2023, I asked if the relevant agency could kindly look into this serious issue and rectify the problem, so as to prevent irreversible damage to the environment and survival of vulnerable wildlife species.

On 13 December 2023, HDB (Housing & Development Board) of Singapore responded to my feedback, saying:

“We refer to your feedback dated 28 Nov 2023, regarding potential environmental issues at Bukit Batok Hillside Park, which was conveyed to HDB by NParks.

2. We wish to share that, following your feedback, our BTO project team carried out an investigation at site with specialists of various field (hydrology, environmental management, erosion control, etc). The investigation showed that there was no silty runoff from our BTO sites into the stream and the silty water you observed likely originated from exposed soil at other parts of the hill which got eroded during the heavy downpour. The specialists also verified that the stream flow and clarity are normal; the effect of silty water to the stream is therefore transient and there were no signs of stress to its ecology.

3 We noted the concerns you shared on behalf of the community. Our BTO sites will continue to maintain effective Earth Control Measures (ECM) and monitor the situation with support from the specialists.”

However, my personal observations on site show that the silty runoff flowed from the West Hill BTO housing site (where densely growing trees have been cut down to make way for buildings), contrary to HDB’s claim, as shown in greater detail in the video below.

Also, it is possible that this siltation or water contamination issue has been going on for some time, probably weeks or months, and I believe it will have caused considerable stress to the ecology of the stream, especially along the stretch where it flows into the pond.

Date and time stamp as well as map location of the video showing the silty runoff flowing into the natural stream on 28 November 2023, 3.57 pm

The stretch of the stream in the lower course of the drainage system where the muddy water ends up in the pond.

Hence, HDB’s claim that “there were no signs of stress to its ecology” is debatable. For example, I remember seeing many dragonflies around the pond/marsh in previous visits, and I didn’t see any dragonflies during my brief visit on 28 November 2023, so I wonder to what extent these creatures have been affected by the siltation.

Flashback: Aerial view of West Hill BTO worksite at Bukit Batok hillside park area, dated 3 July 2023. A section near the eastern boarding appears to have exposed soil. Could it be the source of the water pollution, where the silty runoff occurs whenever there is heavy rain?

Flashback: The water in the pond downstream of Stream A was much clearer about a year ago, such as shown here on 17 August 2022.

Update on stream observation at Bukit Batok hillside park on 16 & 25 December 2023

There appears to be marked improvements in the water quality along the natural freshwater stream, as the silty runoff was no longer seen during the heavy rain.

I suppose the HDB contractors would probably have stepped up their Earth/Erosion Control Measures (ECM) by that time.

That also suggests the silty runoff did originate from the West Hill construction site rather than from other parts of the hillside park forest.

Ultimately, regardless of whether or how much of the silty runoff originated from the construction site or other parts of the hill, the fact remains that soil erosion is mainly caused by the clearing of the forest and the exposure of bare soil to the rain.

Hence, there must be accountability and responsibility on the part of the developer in applying effective mitigation measures to prevent siltation of the rare natural freshwater stream and minimise/avoid harm to the ecosystem and biodiversity in the vicinity at all times.

Littering and water pollution in Kallang River

About seven years ago, I wrote to the Straits Times forum:

“It has been said that Singapore is not so much a “clean” city as it is a “cleaned” city. I agree. On 23 August 2016, I saw lots of rubbish floating in the river next to Braddell bus depot. It must have been washed into the river from drains flowing through Bishan and Toa Payoh after a storm.”

Water pollution issue in Singapore

Although Public Utilities Board (PUB) responded by sending contractors to clean up Kallang River after that, I noticed that the water pollution would recur over the years.

Earlier today, I observed the same problem at Kallang River while doing my lunch shift at Potong Pasir.

The discarded trash, such as styrofoam boxes and plastic waste, not only affects the aesthetic value of the environment, but also harms the aquatic life in the water, which in turn affects other wildlife, such as smooth-coated otters and white-bellied sea eagles, who have been spotted hanging around there.

As if to confirm my thoughts, a white-bellied sea eagle appeared in front of me and swooped down to catch a fish while I was taking pictures at the river bank.

One can only hope that the eagle won’t suffer from food poisoning after eating the fish caught in the polluted river.

“When we do not think about how our actions affect the animals, plants and the environment, our actions will ultimately affect ourselves adversely because we are all interconnected in the ecosystem.”

Water pollution issue in Singapore

Let us continue to do our part in taking care of Nature by not littering, by disposing trash responsibly, and by practising the 4Rs (Refuse, Reduce, Reuse, Recycle).

Water pollution issue in Singapore

How does Singapore compare with five other cities regarding making room for Nature?

Skyline of Marina Bay at Singapore city (Photo by Jimmy Tan)

An article by BBC Earth explores how “six cities have found ways to incorporate greenery into their cityscapes – to the benefit of their populations and the environment.” They include Singapore, Curitiba, Izmir, New York City, Seoul and Liverpool.

According to the article, “these projects from all around the globe show just how possible it is to incorporate nature into every cityscape. Some of these ventures are large scale, while others have a far more localised impact – but all are innovative and inspirational ways to give the whole planet a helping hand, even in the most urban of environments.”

However, the six cities do not all experience the same climates and are not on equal footing.

Climate regions of the world, with approximate locations of the six cities (Base map by BCG Harlem)

Among them, Singapore is the only lowland city experiencing tropical climate with warm, humid and wet weather all year round because of its location at the Equator, so it definitely needs a lot more dense greenery, aka forests (which used to cover almost the entire island, compared to about 20 percent today), both for our survival and quality of life.

In contrast, Curitiba in northwest Brazil, the only other tropical city, is located close to 1,000 m in elevation, which experiences cool mild temperatures all year round, so the population can still get by without having much dense vegetation.

The other 4 cities – Izmir, New York City, Seoul and Liverpool – all experience moderate Mediterranean or cool temperate temperatures, with seasonal changes, so they also don’t need many dense forests for survival or a high quality of life.

Climate graphs of the 6 cities (Source: Climate-Data.org)

At the most, these temperate cities may suffer heat waves during summer, but they enjoy cooler weather in spring, autumn and winter.

On the other hand, Singapore has to endure warm temperatures all year round, which has been intensifying over the years to the point that we recently experienced a record maximum temperature of 37 degrees Celsius in Ang Mo Kio on 13 May 2023.

Aerial view of Ang Mo Kio housing estate dated September 2022 (Photo by Jimmy Tan)

In conclusion, while the efforts to green the cityscape by NParks and community volunteers deserve recognition, Singapore needs to do much more than the other cities to conserve and restore the forests, in order to not only boost our climate resilience but also protect our biodiversity as well as our health and well-being.

Pulau Ubin cleanup event (22 July 2023, Saturday)

Organised by the founder of Pulau Ubin cleanup group, Samuel Gmehlin, this environmental cleanup event was attended by about 20 volunteers.

My teammates picked up about 137 kg of discarded trash by the end of the 1.5 hour session in the central part of the island near the main jetty.

The collected rubbish includes old wires, drink cans, plastic bottles, styrofoam boxes, and so on.

Located between Peninsular Malaysia and mainland Singapore (which itself is an island), Pulau Ubin regularly serves as a stepping stone for wildlife migrating or escaping deforestation in Johor, the southernmost state in Malaysia.

Notable wildlife from Malaysia that has sought refuge in Pulau Ubin over the years include elephants and tapirs, who are rare and endangered.

Thus, it is vital that Ubin island remains as rustic and clean as possible in order to ensure that the forest habitat is conducive for the wildlife to survive.

Pulau Ubin cleanup (near Jalan Durian), 10 June 2023

Almost a decade ago, I lamented in a blog post that “littering and improper waste disposal are still a perennial problem, especially along the southern and eastern coasts of Pulau Ubin”.

Today, I found myself in the eastern forest of Ubin island taking pictures of a cleanup event as a voluntary photographer.

Although picking up trash is by no means dealing with the root cause of the persistent environmental problem, it can raise awareness of this issue.

Besides, there is a sense of purpose and camaraderie among the volunteers who set aside time on a Saturday afternoon to help make the world a better and cleaner place for all.

Along the way, I saw native white-bellied sea eagles soaring in the clear blue sky amidst the cumulus clouds above the coast.

Globally endangered long-tailed macaques were also seen hanging out along a trail off Jalan Durian.

They looked relaxed and didn’t approach us too closely, nor were they aggressive in any way, which I believe is a good sign that they haven’t been fed or provoked by human visitors.