Early in the morning, my group from the NUS GE3255 module embarked on a field trip down the Coastal Trail of Sungei Buloh Wetland Reserve (SBWR). We struck the perfect time to be there as the tides were low and the mudflats were teeming with wildlife. However, a thought had crossed my mind… how could this flourishing mangrove ecosystem be located this close to the shores of Malaysia, where the scenery across the waters was plastered with nothing but buildings?

Johor Urban Development Across the Johor Strait (Source: Ann Ralls)

I wanted to know if the construction in Malaysia had sent more sediments towards SBWR, and how affects the health of this thriving ecosystem. I turned to the data we collected later that day to analyse the water’s sediments.

Horiba Water Quality Meter used to Measure Total Dissolved Solids and Turbidity (Source: Collin Chua)

We found that although the total amount of dissolved solids at the surface and near the bottom of the Buloh Besar tidal slough were nearly identical, the turbidity of the water at these two depths differed by over four times! Upon reflection, I thought that as the tide continued to flow out of the mangroves, a large amount of sediments would be deposited onto the mudflats, ultimately smothering mangrove roots with sediment build-up. This happens as sediments that are denser than water sink to the riverbed and stay there as the tides roll out, and may settle around mangrove roots that are used for the plant to breathe! Additionally, if turbidity close to the riverbed got too high, not enough light would penetrate through to newly-deposited propagules, preventing their growth.

However, I found that not only were the root adaptations of mangrove tree species advantageous for the plant to receive oxygen in hypoxic soils, but they also allow trees not to be smothered by sediments deposited near its base… how clever! Take a look at those pencil roots (pneumatophores) that are growing everywhere out of the soil!

Pencil Roots Emerging From the Mudflats in SBWR (Source: Ann Ralls)

Overall, I’ve learnt on our field trip to SBWR that mangrove restoration is crucial for shoreline resilience, wave breaking and wildlife support, and is more vital than ever in an increasingly urbanised world. My recommendations for future mangrove restoration projects would be to ensure that there are no new urban development plans close by, or to restrict construction work at the doorsteps of mangrove ecosystems. “Earth Control Measures” could be used to stop excessive sediments from entering mangrove ecosystems – for example, sediments can be trapped in gabions (a metal cage of rocks) upstream before reaching mangroves!

Finally, I would love to show you why SBWR is unique to Singapore through its wildlife! Check out the Buffy Fish owl my friend captured on this trip. It’s definitely worth the travel time to visit!

Buffy Fish Owl (Source: Collin Chua)

Written by: Ann Ralls