UNESCO, in partnership with the FAO & IUCN, carried out a field excursion into the mangroves of Samut Songkhran, on the 19th of August. Participants included specialists, as well as the general public, with adults and children.
Aspects, such as the urgent need for better mangrove conservation and restoration, were addressed. The unique ecological niche of mangroves, being located in the inter-tidal zone, thus being exposed to inundation with seawater at high tide, and to air at low tide, as well as the fact that mangroves are tolerant to high salinity, were discussed.
The aspect of above seawater salinity tolerance was elaborated on, related to the fact that our plant’s water resources are made up of ca. 97 % saline water, whereas the existing freshwater resources are only 2-3 %. Therefore, salt-tolerant plants, such as mangroves and other halophytes, have a huge potentially for biomass production, without the need for freshwater. The biomass can potentially be used for the production of food, fibre, fuel, and construction materials. This, of course, needs to be developed in tune with the urgent need for better protection of natural mangroves, of which globally 35 – 50 % have been lost. We need to conserve what we have and restore what we have lost. This was also the motto of the excursion.
Mangroves are of great significance to local ecological environment also because their dense root system contributes to reduce coastal erosion. Their aerial roots sticking out of the ground could slow down water flow and promote sedimentation. The complex root system of mangroves could filter nitrates, phosphates and other pollutants in the water and improve the quality of water flowing from rivers to estuaries and oceans. Meanwhile, mangroves have important coastal disaster prevention and mitigation functions, such as providing shelter against waves and storm surges during near-shore flood disasters.
Birdlife and monkeys in the mangroves were observed, as well as marine biodiversity including mud-skippers, bivalves, and crustaceans. Mangroves provide habitats and refuges for a variety of wildlife such as birds, fish, invertebrates, mammals and plants. Estuary habitats with mangrove coastlines and tree roots are usually important spawning and breeding areas for juvenile marine species and many commercial fish. For many marine species, the mangrove forest is a “nursery” in their early life. The branches of the mangroves can be used for nesting of coastal wading birds, such as egrets, herons, cormorants and roseate spoonbills. The roots of mangrove trees are ideal habitats for oysters.
The immense capacity of mangrove biomass and soil for the sequestration of atmospheric and oceanic carbon was discussed. Mangroves absorb large amounts of carbon and store them in the sediment for thousands of years. Scientists dug samples from the roots of coastal mangroves and tropical mangroves, and found that the peat layer of coastal mangroves can be traced back two thousand years. The coastal mangrove system stores more than five times as much carbon underground as the tropical forest system. Living mangrove biomass is very important for maintaining the world’s carbon balance. This buried carbon is stored underwater in coastal ecosystems, such as mangroves, seagrass beds, and salt marshes, and is called “blue carbon”.
The adaptation of mangroves to germinate and seek anchorage rapidly in the soft-muddy semi-sub-hydric substrates was demonstrated, by dropping the arrow-shaped propagules from a height of 4 meters into the substrate. The fruit of the mangrove forest does not break away from the mother tree in the early stage, but continues to grow on the mother tree, sprouting hypocotyls, and then leaving the mother tree when the hypocotyls mature, and are scattered in the tidal flat. When encountering a suitable environment, they will take root and sprout quickly. Moreover, the hypocotyls are rich in nutrients and tannins, ensuring the consumption of long-distance drifting and avoid seawater corrosion or animal bites. This method of reproduction allows mangroves to overcome the intermittent tide washing environment and reproduce smoothly.
Finally, the local community leader gave a presentation on mangrove conservation and restoration costs, sponsorship programmes, survival rates of restored mangroves, as well as the planning, implementation and seeking further support for nature conservation and restoration.
From this trip, one of the lessons we learned was the importance of the public and youth’s involvement. For example, one participant mentioned that since his elementary school teachers taught him that littering was immoral, he is now a conscientious adult. The same, after exploring mangroves and seeing how monkeys, mud-skippers and crabs live in this biosystem peacefully, he better understands the importance of mangroves and our need to conserve and restore it. From him, we can also imagine that if more people, especially the young, who are impressionable and extremely receptive to new ideas, attend workshops about mangroves and visit mangroves themselves, it is less likely that they will become the one who destroy mangroves in the future.
It is vital that school children are taught to integrate conservation into their subconscious thinking, so that all their actions reflect measures for reducing the adverse environmental impacts of human actions. Thus, the aim of the field excursion is to increase awareness among the public on mangroves ecosystem and its importance. This kind of educational programme can ensure that useful information was being conveyed to students at an early age and empower them to create the world they want to inherit.
Therefore, UNESCO and partners have decided to arrange for a larger field excursion into the mangrove conservation sites of the Ranong UNESCO Biosphere Reserve and the Satun UNESCO Global Geopark, in 2021, possibly with a significant aspect of high school and university student participation, with the objective of enhancing knowledge and skills for nature conservation needs.
Quest 4 Action
Haoyu Jiao, Kuanyi Shen & Benno Böer