NParks' research shines light on 'mother' of northern mangroves

A 2013 file photo of biology lecturer N. Sivasothi (left) and mangrove expert Dan Friess, both from the National University of Singapore, at a mangrove area in Mandai.
A 2013 file photo of biology lecturer N. Sivasothi (left) and mangrove expert Dan Friess, both from the National University of Singapore, at a mangrove area in Mandai.ST FILE PHOTO

The Sungei Buloh Wetland Reserve has for years been the poster child for mangrove forests in Singapore, but now studies have shed light on its quietly giving "mother".

The Mandai Mangrove and Mudflat, located about 3km east of the reserve, has been found to be the main "seeding source" for mangrove propagules for many other mangrove areas.

These areas include the wetland reserve, as well as the mangroves in Kranji, Lim Chu Kang and other downstream mangrove areas, according to research by the National Parks Board (NParks).

The findings were made through a "predictive agent-based model for mangrove propagules" developed in 2016 by NParks.

The model essentially incorporates information on currents, habitat condition, and other biological and ecological parameters of the mangrove propagules.

"Such studies guide our conservation and habitat enhancement efforts," said Dr Adrian Loo, group director of conservation at NParks.

"The decision to safeguard buffer zones and complementary wetland habitats around the Sungei Buloh Wetland Reserve was determined through extensive research that established the ecological connectivity and complementarity between the sites," he added.

Last month, the Sungei Buloh Nature Park Network was launched in an effort to safeguard wetland habitats and strengthen the conservation of wetland biodiversity in the northern region.

Key habitats along this network include the existing Sungei Buloh Wetland Reserve and Kranji Marshes, as well as the upcoming Mandai Mangrove and Mudflat, which was designated a nature park in 2018 and is estimated to open to the public in 2022.

These habitats are also crucial feeding grounds for wildlife.

Bird surveys, as well as radio and satellite tracking technology, have shown that the majority of the shorebirds that roost in Sungei Buloh Wetland Reserve at high tide will forage at the extensive Mandai mudflat exposed at low tide.

The Mandai Mangrove and Mudflat, located about 3km east of Sungei Buloh Wetland Reserve, has been found to be the main "seeding source" for mangrove propagules for many other mangrove areas.

"This means that both sites are ecologically inter-dependent habitats for shorebirds," said Dr Loo.

On land, trees usually produce seeds that get dispersed and germinate thereafter.

But many mangrove species are unique in that they have seeds that germinate while still on the parent plant. At this stage, they are known as propagules.

"The propagules detach from the parent plants and are dispersed by water until they are implanted in a favourable location," said Dr Loo.

National University of Singapore mangrove expert Dan Friess said having a good source of propagules is the first step for a thriving network of mangroves in the north.

But propagules also face many challenges before becoming trees.

 

"Most importantly, it has to find a place where the conditions are suitable to grow. This means a place where there aren't too many waves to dislodge it, and where the regular tidal flooding is at a level that the seedling can tolerate," said Associate Professor Friess.

Dr Loo said NParks will continue to work with researchers and other experts to validate and build on the mangrove model, to increase understanding of the ecological connectivity between mangrove areas in Singapore.

In an interview with The Straits Times earlier this month, National Development Minister Desmond Lee had noted that the tussle between development and conservation will be a perennial challenge for land-scarce Singapore.

 

But science and technology could help in the decision-making process, he added, citing the conservation of the Mandai Mangrove and Mudflat as a nature park.

"The Mandai Mangrove and Mudflat will be what it will, because we have agent-based modelling... (to determine) where are the sources and sinks," he said.

This had also been done for the Sisters' Islands Marine Park, Mr Lee added.

 

"It is what it is in terms of its current status as a marine park because of science and data... and then we make the case, and then we strike a balance."

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A version of this article appeared in the print edition of The Straits Times on September 19, 2020, with the headline 'NParks' research shines light on 'mother' of northern mangroves'. Print Edition | Subscribe