Ecological and economic value of mangroves

 
A complex ecosystem and cycle of substances
 
Many organisms are living in the mangrove forests. By visiting the mangroves, you can watch the shrubs, the birds and the crabs. In the tides, all the little creatures move around, look for food and reproduce their offspring following the tempo of the nature. An interdependent relationship in the circle of nature was established between the many kinds of living things inside mangrove forests. Plants in mangrove forest provide organic crumbs for crabs, fishes and shellfishes, and they provide food for raptors of different sizes. At the end, all the corpses and excretion of organisms decompose and recycle, going back the the whole region as the most basic organic substances. This is a very complex ecosystem, a food chain relationship and an energy transfer process, which play an imperative role in ecological balance of the nature.
 
Maintaining ecological balance of the nature
By photosynthesis, the mangroves supply nutrients and oxygen to animals and plants in the ecosystem. As mangrove forests link up the ecosystems of the land and sea, their importance in stabilising and reserving the peripheral ecosystems is unquestionable (e.g. every hectare of mangroves can feed 12 tonnes of living things including insects, reptiles, amphibians, birds, invertebrates and various aquatic microorganisms).
 
Foraging and living places for wildlife
Mangrove forests provide abundant food resources. Plants in mangroves can be hiding places and shelters for adverse weather. Many animals spend parts their life cycles, or the entire ones, with the mangroves. The examples are marine shrimps (Penaeus sp. and Metapaneus sp.). Some bird species, mostly waterfowls like egrets, frequently look for food in mangroves. They mainly eat aquatic organisms like fishes, shrimps, crabs and worms. Because of that, the mangroves became their ideal habitat.
 
Reducing water pollution
The root systems of mangrove species absorb inorganic substances and reduce water pollution. Through the metabolism of microorganisms, soil surface absorption, chemical sedimentation and plant digestion, the amount of suspended particles, elements including nitrogen and phosphorous, metals as well as chemical oxygen demand in water can be lowered.
 
Protecting the coastlines
Mangroves can stabilise the coastlines of the river shores and river mouths. They also protect the coastline from wave erosion.
 
Flood prevention
Mangroves can stabilise water capacity of the substratum and on the soil surface, hence steady and retain water to prevent flooding. In recent years, the low-lying areas in New Territories have been affected by floods during thunderstorms. It is largely because the development projects have changed the land use of wetlands.
 
Mangroves and fisheries
Mangroves are important for keeping the fishery yields in coastal and offshore areas. Not only do they supply the coastal habitat with nutrients, they also give an ideal living environment to fishes, shrimps, crabs and other aquatic organisms.
 
Ornamental value
A mangrove forest is a beautiful environment. It provides wildlife places for living and foraging, and gives human places for economic activities (like fishery and agriculture) or interactive classrooms for outdoor teaching. It acts as a sight-seeing route of eco-tours, and it brings financial incentives to the community.
 
Others
 
Charcoal and firewood
A few decades ago, villagers living along the coast of Mai Po always used the wood of mangrove for fuel to cook. In southeast Asian countries like India, Bangladesh, the Philippines, Malaysia and Indonesia, quite a lot of people living offshore are still using mangrove wood as the cooking fuel. In Thailand, some villagers sell mangrove wood as firewood for their livings. Owing to their hardness, high heat emission and little smoke during burning, some species of mangrove are made into charcoal, and they are popular in Thailand and Malaysia. Mangrove swamps and all wetland swamps possess complex ecosystems. They are essential areas for substance cycling on Earth. They are as well the lively classroom for nature observation. It is pitiful that we human, by intention or otherwise, ignored the destructions and impacts to brought to the original environment. Facing the pressure from developments and various kinds of pollution, the living place for mangroves and the wildlife is shrinking.

The Conservancy Association is carrying out a series of wetland conservation, education and promotion programmes. If you are interested in the related information and want to join us in protecting the wetland, please contact us.