Unlike its counterparts in the uplands, mangroves are somewhat neglected. Most environmentalists and some media howl when forests are trimmed down. But there’s not so much noise when it comes to mangroves.
Another ecosystem that is not being paid attention to are the seagrass meadows. In fact, no one bothers about them. But what most Filipinos don’t know is that our country has the second highest number of seagrass species in the world. We have 16 of the globe’s 50 known seagrasses. Only Western Australia has more, but just by one species.
Perhaps it may come as a surprise that both mangroves and seagrasses have the natural capacity to sequester the carbon dioxide which are released into the atmosphere. Over the centuries, they have stored enormous amounts of “blue carbon” in their sediments.
“As carbon sinks, they are a cheap and readily available natural resources useful in mitigating the negative impacts of climate change,” said Dr. Miguel D. Fortes, a retired marine science professor at the marine science institute of the University of the Philippines at Diliman.
He knows what he is talking about. He has more than two decades of experience as a coastal zone ecologist with research focus on coastal and marine resource assessment and sustainable use. He is also the first Filipino to receive the prestigious International Biwako Prize for Ecology.
“Unfortunately, they are at great risk of being lost and if the trend continues at current rates, a further 30-40% of seagrasses and nearly all unprotected mangroves could be lost in the next 100 years,” he warned.
Mangroves are very important to marine life. They serve as sanctuaries and feeding grounds for fish that nibble on detritus trapped in the vegetation, and on the bark and leaves of living trees.
From 450,000 hectares in the 1920s, there are only less than 100,000 hectares left of our mangrove forests. Most of these mangroves are “secondary growth” and only a small portion is primary growth, mostly in Palawan and a little in Mindanao.
According to Dr. Fortes, all 16 seagrass species are widely distributed in the country: from Bolinao Bay in the north, Palawan and the Cebu-Bohol-Siquijor area to the center, and Zamboanga and Davao in the south. Seagrass beds cover an estimated area of about five million hectares.
A report from the Department of Environment and Natural Resources said the Philippines lost about 30-50 of its seagrasses. This was 17 years ago; the figure may be dwindled as more coastal areas are being developed for various uses.
“Once they are degraded or destroyed, their blue carbon stores are released as carbon dioxide and contribute to global climate change,” warned Dr. Fortes in a position paper which I obtained.
Recent studies have shown that mangroves, seagrass meadows and tidal marshes (this is not found in the country) mitigate climate change by sequestering carbon dioxide from the atmosphere and oceans “at significantly higher rates per unit area” than terrestrial forests.
“The carbon within these systems are stored aboveground (tree trunks, stems and leaves), belowground (root systems and rhizomes) in the plant biomass and in the carbon-rich organic soils of these ecosystems for even thousands of years,” explained Dr. Fortes.
The annual carbon sequestration rate for mangroves averages between 6-8 megarams (tons of carbon dioxide equivalent per hectare). One megagram is equal to one million grams. “These rates are about two to four times greater than global rates observed in mature tropical forests,” the Filipino marine scientist said.
Seagrasses account for less than 0.2% of the world’s oceans but they sequester approximately 10% of the carbon buried in ocean sediment annually, according to Dr. Fortes.
“Current rates of loss of these ecosystems may result in 0.15 to 1.02 billion tons of carbon dioxide released annually,” he pinpointed. “Hence, it is imperative that these blue carbon ecosystems be conserved and well-managed.”
In his position paper, Dr. Fortes pushed for the formulation of a blue carbon research and development. Consistent with the policies laid down by the International Blue Carbon Initiative, the country’s program on the matter should aim to do the following:
Fully integrate the outcomes into the natural coastal conservation and management policies and carbon financing (e.g. voluntary carbon market) of the government as part of mechanisms for climate change mitigation;
Incorporate the outcomes in appropriate regulated processes of government as part of an integrated output of scientific research, policy design, economic analysis and policy advocacy;
Integrate the outcomes into other national, regional and international coastal and marine regulatory frameworks and policies;
Facilitate the inclusion of the carbon value of coastal ecosystems in the accounting of ecosystem services; and
Harmonize existing guidelines and policies governing conservation and management of seagrass, mangroves and coral reef ecosystems.
“In the Philippines, knowledge is still insufficient to develop effective carbon policy, management, and conservation incentives for coastal blue carbon, despite the preponderance of studies on coral reefs, mangroves and coastal management undertaken in the 1980s till at present,” Dr. Fortes lamented.
