Hello guys! Last week Sarah-Ann posed me a thought-provoking question regarding trash accumulating in our mangroves, and coincidentally last Saturday I went down to Sungei Pandan Mangroves to participate in a cleanup organized by the BES Student Committee. So I thought it would be really apt to reflect on this issue this week while the experience is still fresh in my mind.

On Saturday, we began our cleanup at the Sungei Pandan Mangroves at around 2pm. The tide was high and just beginning to recede, hence my 3-person group’s area of responsibility was limited to only about a 15m stretch of the upper shore. Yet, the moment we entered the vegetation and set foot onto the mangrove shore, it was clear to me that we were going to have quite a bit of work to do!

While it wasn’t like those horror pictures on the internet of beaches covered in plastic bags, distinct pieces of litter were immediately visible, especially in patches overgrown with roots and branches. My group and I spent the next hour or so attempting to pick as much trash as we could, while documenting on a data sheet how many of each kind we collected. The most common items we found were food wrappers, kopi takeaway bags, straws and cigarette boxes.

After everything was done, we had a little conversation with Prof N Sivasothi, our locally renowned Otterman, who shared with us some insights into the situation there. He told us that what we experienced was only a “low load” of litter, as cleanups were conducted at least annually. If that was a “low load”, I shudder to imagine what a “high load” would look like! He also mentioned that the trash tended to be washed in from the sea, from as far away as the Riau Archipelago.

Looking back, I infer that the trash in Sungei Pandan Mangroves comes from 2 main sources, namely from people who physically litter there, and washed-in marine litter/debris. Perhaps because my group worked on the upper shore which is above the high-tide line, we mainly picked up litter deposited in-situ by workers from the adjacent industrial estates who go there to “chill”. My course-mates who worked on the lower shore later on reported that their most commonly found litter was “broken-down debris”, particularly styrofoam and plastic pieces, which probably belong to the latter category of trash.

What do these mean to us? We cannot blame our mangrove trash solely on washed-in marine debris. Instead, we need to be acutely aware that our local littering habits can also be a major contributor to the issue. Hence, we must advocate for more responsible litter disposal.

Now back to my thoughts on mangrove trash. In my reply to Sarah-Ann, I raised the idea of utilizing our mangroves as a natural filter to collect marine debris, which we can periodically clear as part of efforts to clean up our coastal trash. My main gripe with this is the excessive trampling that could occur from overly frequent cleanup projects. Studies have shown that human trampling into mangroves can cause significant reduction in quality and quantity of mangrove roots, as well as adversely impact the macrofauna present (Ross, 2006). If mangrove cleanups were to happen too regularly, this impact would inevitably be of considerable significance. There is limited research available on the negative impacts of mangrove cleanups, but my take on this now is that it is not feasible to treat our mangroves as a natural “dustpan”. The ecological cost would be too high, and ecosystems are usually best left untouched. Rather, the best we can do is to have a basal level of tolerance to “low loads” of litter, while conducting cleanups just regularly enough to keep litter level at a minimum.

See you all next week! Cheers!

References

Ross, P. M. (2006). Macrofaunal loss and microhabitat destruction: The impact of trampling in a temperate mangrove forest, NSW Australia [Article]. Wetlands Ecology and Management, 14(2), 167-184. https://doi.org/10.1007/s11273-005-7552-y