Rony V. Diaz, The Manila Times 8 Jun 08;
THE storm surge that devastated villages in Irrawaddy at the height of cyclone Nargis would have been less destructive if there were mangroves in the estuaries and mudflats of the delta.
Mangroves are among the best natural defense of sheltered coastlines against wind and water during storms. This is one of the lessons of the tragedy in Myanmar that we should not overlook.
There were, at one time, according to the World Mangrove Atlas (International Society for Mangrove Ecosystems, Okinawa, Japan, 1997), more than 200,000 square kilometers of mangrove forests in tropical and subtropical coastlines all over the world. They have been disappearing at the rate of one percent to 2 percent a year or at about the same rate as the disappearance of coral reefs and rainforests. The rate of loss is faster in developing countries where in the last 25 years 35 percent to 86 percent of mangrove forests have been destroyed, according to the Food and Agriculture Organization (FAO) of the United Nations.
In the Philippines, the rate of destruction, extrapolated from international data sources, is between 40 percent and 45 percent in the last 10 years. Mangrove areas in Bulacan, Davao, Palawan, the two Mindoros, Bohol, Samar and Zamboanga have shrunk, putting their long-term survival at risk. If this rate of loss is not reversed, we would have no mangrove stands by the middle of the century.
Mangrove destruction is due mainly to human settlement and aquaculture but as the pace of urbanization quickens, reclamation and pollution will begin to take their toll.
Mangrove forests are ecosystems that sustain unique plant and animal species, many of which we still have to discover and study. It’s possible that many of them have become extinct with unforeseen effects on fragile mangrove ecology. Loss of functional diversity is particularly serious because mangrove ecosystems are species-poor. The FAO reports that in 26 of 120 countries, mangroves are critically endangered or fast becoming extinct. (“Status and trends in mangrove area extent worldwide,” FAO, 2003).
What are the known consequences of mangrove deforestation?
Mangrove ecosystems are an integral part of terrestrial and marine food webs. Their destruction will have an immediate effect on fishery productivity.
Mangroves also protect seaweed beds and coral reefs against river-borne silts and serve as breeding ground of certain species of fish that thrive in brackish water.
They also maintain salt marshes as filters of industrial and household wastes.
Certain species of mangrove are sources of fibers, chemicals and medicine. Palawan mangroves, for example, are raw materials for Japan’s chemical industries.
Mangrove forests function both as an atmospheric CO2 sink and a source of ocean carbon. They are important in the effort to slow down global warming. (E. McLeod and R.V. Salm, Managing Mangroves for Resilience to Climate Change, IUCN, 2006)
Finally, as said earlier, mangrove forests protect human settlements near coastlines from rising seas, storm surges and tsunamis. Myanmar, Thailand, Indonesia and India are object lessons.
In light of all this, there’s an urgent need to conserve, protect and renew the mangrove trees and shrubs in sheltered coastlines and tidal wetlands. The endemic species—Rhizophora mangle, Avicenna nitida, and the Sonneratia varieties —are relatively easy to propagate.
Effective and enforceable policies and education strategies have to be implemented right away to reverse the loss of mangrove forests.
The Department of Agriculture, the Department of Environment and Natural Resources and UP Los Baños should lose no time in putting together a plan to save and to expand the mangrove forests of the Philippines.
