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Are Singapore’s mangroves to remain ecologically-sustainable over the long-term?

In conjunction with the World Migratory Bird Day on 12 May 2012, Sungei Buloh Wetland Reserve (SBWR) organized several talks and an exhibition to celebrate the World Migratory Bird Day and   its role as  a roosting ground for migratory birds.

Although migratory birds were made the main focus of the event, mangroves and its mudflats that provide habitats for the birds were not neglected during the celebration.

Mangrove Maestro a.k.a. Dr. Dan Friess held an educational talk to SBWR’s visitors on the state of Singapore’s mangroves and how the public volunteers can assist NParks in their investigation of the current state the mangroves.

Title of Dan’s talk

Dan introducing title of his talk to his attentive audience

Highlights of the talk

Dan talked about mangrove loss around the world and in Singapore itself.

Evidence statements of mangrove loss worldwide

A substantial decline of Singapore mangroves was recorded since  the 1950s.

Singapore has lost a lot  of mangroves over the past 50 years. In addition, our mangroves  have been and are currently facing threats to their survival. To illustrate the threats faced by Singapore mangroves, Dan has used Mandai mangrove as a case-study to exemplify the threats.

List of threats faced by mangroves of Singapore

Sea level rise  (SLR) threat: mangrove  would survive and expand when the increase in surface elevation > increase in SLR.

Otherwise,  mangrove degradation and erosion, as seen in Mandai and Sg Buloh is  due to surface elevation < increase in SLR.

Sea level rise is dependent on surface elevation and sea level ; these factors affect life and death of a mangrove patch.

Damming of Kranji River has caused  a major loss of sediment input for Northwest Singapore mangroves including Mandai and Sg. Buloh-therefore leading to erosion i.e. reduced sediment input vs. sediment output

Dan also talked about the impacts on coastal reclamation which have led to disconnection of mangroves i.e. fragmentation  mangrove areas. For example, Mandai mangrove and SBWR are no longer connected as a Northwestern mangrove patch.

Another threat to survivability of mangroves: fragmentation!

So why mangrove  fragmentation is bad?

Mangrove fragmentation would eventually  lead to disturbance of  flora and fauna species near the edges of a mangrove patch. Sensitive animals would not be able to cross over to another mangrove patch to search for food, mating partners, etc and therefore may not survive.

Plant wise, some mangrove tree species disperse their young i.e. propagules to different places via water dispersal. Therefore, if  mangrove patches are disconnected, mangrove trees cannot disperse their propagules to neighbouring mangrove patches.

Different mangrove propagules of different mangrove species found in Singapore. Picture courtesy of Ria Tan from Wild Singapore

Rhizophora propagules disperse via water currents

Dan channeling his ‘wit’ by placing a Sonneratia propagule over his nose!

Illustration on how fragmented mangroves will influence the dispersal properties of mangrove plants

The disconnection often leads to short-term sustainability of mangroves i.e. mangroves will eventually die! Noooooooo….

Therefore, NUS and NParks are collaborating on several projects to investigate the scale of mangrove fragmentation  in Singapore by predicting  the sustainability of  Singapore’s mangrove.

Effects of mangrove fragmentation on mangrove dispersal

How  do we investigate the fragmentation status of Singapore’s mangroves?

Fruiting  and flowering seasons of our mangroves will be studied. Meanwhile, NUS PhD student Alison Wee is currently conducting research on gene flow of our mangroves.

Combined with data from a hydrodynamic model, the extent of the fragmentation in Singapore’s mangrove will be better understood in order to mitigate plans to save and conserve our mangroves from further loss.

Studying fragmentation of Singapore’s mangrove from several aspects


You CAN play a role in the project! How? NParks is looking for public volunteers who are interested to help collect, count and sort propagules of mangrove trees in SBWR.

Volunteers can assist this project by several ways

Please contact Dr. Friess at  if you are interested to help out with the project.

Andy has been kind enough to record the whole-length of the talk (thanks Andy!), feel free to watch the talk below: