“City in Nature” – Singapore’s oft-quoted slogan representing its aspirations to be a modern yet biophilic city, in which a world-class built environment and natural greenery co-exist in harmony. Where better to learn about Singapore’s “City in Nature” ambitions than its most famous nature heritage site, the Singapore Botanic Gardens (SBG). On my “GE4224: Applied Biogeography” learning journey in SBG on 5 February 2022, I had the opportunity to learn about one of SBG’s major restoration projects: the Keppel Discovery Wetlands (KDW).

Figure 1: A visitor’s picture of the Keppel Discovery Wetlands in the year it was opened. Photo by: Little Day Out, 31 March 2017.

KDW is a restored wetland forest ecosystem (Fig. 1) inspired by maps of its historical natural environment from the 19th century (although this map was itself produced after some human modification to the original site had already taken place). KDW was restored using engineering and landscaping techniques that facilitates the collection and retention of rainwater in the wetlands (Fig. 2), with the end-product being its eye-catching marsh lake. Much of this restoration work was funded by a $2.08 million grant from Keppel Corporation.

Figure 2: Example of weirs and sluice gates (in the middle ground), engineering installations used to retain water in the wetlands. Photo by: Elliott Foo, 5 February 2022.

KDW provides the public with an excellent opportunity to learn about the important ecosystem services that wetlands provide (e.g. regulating natural water flows), as well as the fascinating biota it supports. Examples of the floral life that have made their home in KDW are various species of aquatic plants like rushes and sedges (Fig. 3). These plants have a special adaptation to the wetland’s anoxic water and soil conditions known as aerenchyma, which are tissues that help facilitate gas exchange. Some plants have also been specially planted along the wetlands’ edge to simulate the succession of flora that occurs in wetland ecosystems in the Malayan Peninsula (Fig. 4), an acknowledgement of the wider natural environment Singapore is situated in.

Figure 3: Picture of a species of rush that is adapted to growing in the water-logged conditions of KDW. Photo by: Elliott Foo, 5 February 2022.

 

Figure 4: Picture of Barringtonia reticulata (Sumatran Putat) in KDW, a tree that grows in the Putat-belt vegetation zone along wetlands in Malaysia. Photo by: Elliott Foo, 5 February 2022.

Singapore’s only remaining sizeable freshwater wetland ecosystem is the Nee Soon Swamp Forest, where public entry is prohibited to protect its fragile state. Thus, for anyone keen on learning more about Singapore’s freshwater wetlands, visiting KDW is perhaps the only way to get first-hand experience – this is not an opportunity to be missed for any nature enthusiast! However, despite its many positives, KDW is also facing challenges. The picture of KDW taken in 2017 (Fig. 1) has been a largely accurate depiction of its appearance since it opened, however in recent times, its state has more closely resembled the picture below:

Figure 5: Picture of KDW taken in 2022. Photo by: Elliott Foo, 5 February 2022.

An invasive plant, Hydrilla verticillate (Hydrilla), is now prevalent across the wetlands’ water surface (Fig. 5). How the Hydrilla came to inhabit the wetlands remains unknown, however reasons as to why the problem persists are much clearer. For one, fresh funds for the long-term maintenance of the project likely remain limited, presenting practical challenges to the upkeep of the wetlands. Run-off from nutrient-rich soil in the area surrounding the wetlands, facilitated by the high rainfall of the tropics, is also abetting the Hydrilla’s rampant growth. This speaks to the difficulty of maintaining a restored ecosystem in the city, where nature is desired but the resources and capacity to conserve it are not always available. A volunteer-led effort to clean up the wetlands might be a solution. If so, would you lend your aid?

By: Elliott Foo