Satellite data generated by Global Forest Watch (GFW) under the World Resources lnstitute (WRI) have confirmed the huge loss of mangrove forests in the Philippines, Indonesia, Malaysia and neighboring countries. GFW’s findings were published in the article “Satellite Data Reveal State of the World’s Mangrove Forests,” written by Asa Strong and Susan Minnemeyer for WRI on February 20.
“Asia is a hub for global mangrove loss, with annual loss rates nearly double the global average,” Strong and Minnemeyer said.
“More than half of the mangrove loss over the past decade occurred in the Asia insular region, comprised of Indonesia, Malaysia, Papua New Guinea, Solomon Islands, Brunei Darussalam, East Timor, Singapore and the Philippines,” they noted.
Mangrove loss rates are not as high as the rate of tropical deforestation, but the steady loss rate in the current decade has not reassured experts about its long-term impact not only on fisheries but also on biodiversity.
“GFW data indicate that the world lost between 9,000 hectares and 25,000 hectares of mangroves each year between 2001 and 2012, and that’s not considering the enormous damage done prior to 2001,” the authors argued. Asked for his position on the matter, Filipino fisheries expert Virgilio B. Marzo said local aquaculturists should start working on sustainable ventures. He said one method of producing various types of fish for sale to the market is through the use of water tanks.
Scientifically acclimatizing fish that spawns in the sea in growing areas inland can enable the mature fish to lay eggs in hatcheries and fishponds, Marzo added. “As countries race to protect their forests, they must also protect the vital mangrove ecosystems along their coastlines.
With continued data analysis, conservation, management and restoration, we can halt the loss of the world’s remaining mangrove forests and begin to reverse it,” Strong and Minnemeyer said.
Nevertheless, the loss is particularly worrisome, they added, since it occurs in a region that has the planet’s largest mangrove area that possesses high biodiversity and enormous carbon-storage potential.
“It’s particularly suitable for mangrove growth because of its extensive coastlines, abundant islands, high rainfall and significant freshwater sources,” they noted.
Nonetheless, Asia’s mangroves are at high risk as the aquaculture industry expands to feed a surging global population, with freshwater ventures now producing nearly half of the fish consumed in the entire planet.
“The aquaculture industry is one of the fastest-growing animal-producing sectors in the world, and as it’s grown, so have concerns about its impact on mangroves and other ecosystems,” Strong and Minnemeyer warned.
They said that in the 1980s and 1990s, a largely unregulated boom in shrimp aquaculture led to a clearing of a significant area of mangroves for aquaculture ponds.
Fortunately, mangrove conversion to aquaculture has greatly slowed since 2000, thanks to improvements in shrimp-farming practices and mangrove-protection policies. Still, it’s an ongoing challenge to reconcile plans for aquaculture expansion with mangrove protection in the region, they noted. Encroachment by palm-oil plantations has also been tagged as a major cause of mangrove loss in Asia.
“Oil spills and other chemical pollution, such as fertilizers and pesticides from nearby farms, also pose threats to Asian mangroves, while growing populations increasingly impact mangrove habitats through coastal and urban development,” Strong and Minnemeyer warned.
The only bright spot for mangrove in Asia is the Sundarbans, the world’s largest area of mangrove forest that spans million hectares (2.47 million acres) in India and Bangladesh.
This huge mangrove area has not sustained a tree loss from 2001 to 2012 even as pollution, overexploitation, aquaculture and agriculture threaten the ecosystem.
“The forest is a famous biodiversity hot spot, harboring 270 species of birds, 35 reptiles and 42 mammals, as well as protecting threatened and endangered species like the estuarine crocodile, Indian python and Bengal tiger. Notably, it’s the only area known to have tigers that are ecologically adapted to mangrove habitats,” Strong and Minnemeyer said.
Image credits: AP/Bikas Das