Our Splendid Swamps

In the summer of the last academic year, I joined the Department of Biological Sciences as a part time research assistant helping with surveys in Nee Soon Swamp Forest. While it may sound mundane for most people, it was like dream come true for me. I had always heard about the ecological significance of this area but never had I ever thought that I would have a chance of working in it.

The job scope involved surveying different tree species in the swamp forest for flowers and fruits in order to determine patterns and trends. The forest was divided into different plots which could be broadly categorised into wet and dry plots. Dry plots tend to be located on hillslopes and ridges while wet plots are situated in the valleys. On the first day of the job, armed with binoculars, my colleague and I excitedly made our way to our first wet plot. There, what I saw was vastly different from any of the forests I had seen before. The entire area was flooded and waterlogged, with trees forming a mosaic of small islands.

Flooded swamp forest with a patchwork of trees forming small islands. Source: Me

Some of the trees had unique morphological characteristics and produced massive pneumatophores which were almost a meter in height. Other trees had stilt roots, much like trees from our mangrove forests. The water was very slow flowing and stained brown due to the presence of tannins from decaying vegetation.

Pneumatophores of Lophopetalum multinervium to aid with oxygen intake in anaerobic mud. Source: Me

Stilt roots of an unidentified tree species. Source: Me

After the initial excitement, we got down to work. Using our binoculars, we looked at the crown of the trees for signs of flowers and fruits. After that, the data would be recorded on a data sheet. At times, when the trees were ambiguously labelled, the diameter-at-breast-height (dbh) would be taken and then compared against the value on the data sheet to ensure that the correct tree was being surveyed. While these may sound easy enough, it was more challenging than I had expected. For a start, the swampy terrain and lack of solid ground made navigation a chore as time was spent trudging through the mud. Secondly, some of the tree species such as Lophopetalum multinervium had inconspicuous fruits which made it challenging to spot from the ground, especially when the crown is heavily backlit due to the bright sky above. Lastly, the large number of spiny plants in the plots meant that we were almost always left with small bruises and cuts after every fieldwork session.

The green fruit of Lophopetalum multinervium was difficult to differentiate from green leaves when viewed from afar. Source: Me

Huge spiny Pandanus artrocarpus which can cause cuts and tear clothing! Source: Me

Through the weeks, I started to understand the importance of Nee Soon Swamp Forest. Since the 19th century, freshwater swamps in Singapore have progressively been cleared for agriculture and reservoir construction. [1] Nee Soon Swamp Forest which is a tributary of Sungai Seletar is the last of its kind and was likely preserved through the gazettement of Chan Chu Kang Forest Reserve in 1885. To the north of Nee Soon lies the other tributary of Sungai Seletar which contained freshwater swamps in the past. However, the entire valley and swamp was flooded and consumed during the expansion of Upper Seletar Reservoir between 1940 and 1967. [2]

Although the remaining freshwater swamp occupies a much smaller land area compared to mangroves, it contains over 200 species of plants compared to 30 species found in mangroves. Unlike mangroves, the plants and animals are also exclusively freshwater dwelling, with no adaptations for saltwater. Moreover, many of the flora and fauna found in Nee Soon cannot be found elsewhere on the island. [2] I have included pictures of some interesting flora and fauna spotted during my fieldwork sessions. Nee Soon Swamp Forest is of great ecological significance, with many threatened freshwater creatures confined solely in that area. In fact, it is the only place in the world where the swamp forest crab (Parathelphusa reticulata) is found. [3] As such, I do hope that it can continue being preserved while degraded swamp forests in places like Sime Road and Admiralty Park can be restored, using the methods outlined in a paper by the Nature Society. [2]

Curved Spiny Spider (Marcracantha arcuata). Source: Me

Copper-cheeked Frog (Hydrophylanx raniceps). Source: Me

White Back Giant Flat Millipede (Platyrhacus lineatus). Source: Me

Aquatic aroid Cryptocoryne griffithii growing in a slow-moving stream

Stick insect, most likely Necroscia confusa. Source: Me

While I do not have any specific advice for research assistant positions, I think that for any fieldwork related tasks or jobs, it would be good to be mentally prepared to work under challenging conditions and push yourself. Many of the skills and techniques must be learnt out in the field where conditions may not be the most favourable given the hot and humid weather and tough terrain. Of course, it would help greatly to invest in some outdoor gear such as long pants or boots to make the fieldwork more comfortable for yourself. On a whole, this job was fulfilling, and I finally understood why Nee Soon Swamp Forest is so precious and why we should conserve it for posterity.

Written by: Ke Yao

References

[1]: Corner, E. J. H. (1978). The freshwater swamp-forest of South Johore and Singapore. Singapore: Botanic Parks & Recreation Department.

[2]: O’Dempsey, T., & Chew, P. T. (2011). THE FRESHWATER SWAMP FORESTS OF SUNGEI SELETAR CATCHMENT: A STATUS REPORT, 1–46. Retrieved from https://www.nss.org.sg/documents/Pages 121 – 166 Tony OD & Chew PT THE FRESHWATER SWAMP FORESTS OF SUNGEI SELETAR CATCHMENT.pdf

[3] Clews, E., Corlette, R., Ho, J., Kim, D., Koh, C., Liong, S., . . . Ziegler, A. (2018). The biological, ecological and conservation significance of freshwater swamp forest in Singapore. Gardens’ Bulletin Singapore Hydrology and Biodiversity of Nee Soon Freshwater Swamp Forest, 70(1), 9-31. doi:10.26492/gbs70(suppl.1).2018-02

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