Indonesian mangroves and global warming

Sukristijono Sukardjo, Jakarta Post 12 Dec 07;

The majority of the world's mangroves lie in Indonesia and Indonesian mangroves contribute 27 percent of the world's mangrove area.

Because the mangrove forest grows at the interface between land and sea, the destruction of this ecosystem causes severe damage to both terrestrial and aquatic neighboring ecosystems.

Straddling two environments -- land and sea -- the frontal edge of the mangrove stand is characterized by thick vegetation, tangled roots and glutinous mud.

The soil is periodically waterlogged, rich in organic matter and therefore low in oxygen. Water and nutrients are abundant, but the water is salty. It is called the waterlogged forest.

The environment in which mangroves grow is harsh. Only a few of the mangrove species are normally seen at or close to the water's edge and that is why most people seem to find these forests somewhat monotonous.

The other members of the group tend to be hidden from view by those at the front, but nonetheless often cover large areas and are important in the general ecology.

Rarely are all species found in any one estuary. It is true to say, in fact, that no two estuaries are exactly alike. Like any other plant, each mangrove has its particular environmental preferences.

To the experienced eye, therefore, mangrove forests display far greater diversity than one might imagine and it is beginning to appear these differences may affect such things as fishing.

Only careful research will tell whether or not this is so.

To date, approximately 110 to 204 plants species being found associated with Indonesian mangroves and numerous species of micro flora (fungi, lichens, diatoms and algal), the associated fauna and the microbial species of the soils, waters and air. Some are still waiting a proper identification.

Walking in an Avicennia forest is hampered by a dense growth of short, woody pegs projecting from the soil. These are pneumatophores -- aerial extensions of the mangrove's roots. The prop-roots of Rhizophora spp stabilize the mangrove in soft mud and hold it against currents.

The roots of the living trees serve as hiding places for fish and as substrate for much-desired oysters. The seeds within the fruits will germinate before falling from the tree.

Viviparity, as this phenomenon is called, enables the young mangroves to root quickly.

Tidal forests contain distinctive vegetation zones, reflecting differences in the duration of inundation, the input of freshwater from the hinterland, salinity, geomorphology, human interference and other factors.

Indonesian mangroves grow in areas of high solar radiation and have the ability to take up fresh water from salt, so they are in an excellent position to achieve high primary productivity. Mangroves provide an interesting natural laboratory for ecologists and biologists.

Mangroves are also valuable outdoor classrooms and in the Suwung in Bali for example, boardwalks have been built allowing easy public access. The mangroves of Indonesia's coast are exhilarating to view and exciting to explore.

The republic's mangroves are one of the most important parts of the country's estuaries (as a major component of river-basin or river catchment) and a source of conflicts in terms of tropical ecosystems for the direct and indirect benefits it produces.

The mangrove forest plays many roles including a coastal stabilizer, dispersant of the energy of storms, tidal bores and winds.

It is also a convenient nursery area for fish, shrimp, crabs, mollusks. The role of mangroves in the cycle of nutrients and energy, which makes estuaries among our most important sources of seafood has been recognized only in recent years.

This is a considerable challenge which, if effectively pursued, could prove the only long-term means of sustaining an economically viable fishery.

Mangroves along the coasts of Indonesia are vital for global climate changes and also to South China Sea fishing, ecologists say.

The destruction of Indonesian mangroves by mankind, however, is progressing extensively and intensively in a massive manner. Also, the natural calamities at the present day play a significant role too. We should pay attention to the coastal environment, especially in Aceh, Sumatra Utara and Nias.

Conservation of the mangrove ecosystem is a way for "real lasting development. Because the mangrove forest grows at the interface between land and sea, the destruction of this ecosystem causes severe damage to both terrestrial and aquatic neighboring ecosystems.

The majority of the world's mangroves lie in Indonesia and Indonesian mangroves contribute 27 percent of the world's mangrove area. The time has come for Indonesia to establish a National Strategy for Mangrove Ecosystem Management in Indonesia (NSMEMI) that clearly states the values of mangroves resources to the nation, takes steps to keep our remaining mangrove forests and initiates the process of restoring the mangrove environment for the future.

A national policy must increase the role of resource management agencies in development projects and require that all development agencies prevent mangrove forest loss or fully mitigate such loss when it is unavoidable.

As a national policy develops and is implemented we will see significant changes that not only slow, and eventually stop, mangrove forests loss, but ultimately result in a reversal of mangrove loss.

The establishment and implementation of a national policy (e.g., for green belt, national parks, nature reserve, wildlife sanctuaries) on coastal resources in general and the mangrove ecosystem in particular, will not be easy task, but it is necessary one.

Mangroves mean too much to the national interest to be squandered for quick profits or political expediency. Instead, these tidal wetlands should be declared endangered habitats and given national recognition as a critical resource. The question is do we Indonesians have the will?

The writer is professor of mangrove ecology at the Center for Oceanological Research and Development, Indonesian Institute of Sciences (LIPI), Jakarta, Indonesia.