Mark Kinver BBC News 4 Jan 16;
The threat posed by the development of rice and palm oil plantations to mangroves in South-East Asia has been underestimated, a study has suggested.
Rice and oil plantations accounted for 38% of mangrove deforestation between 2000 and 2012, the research showed.
As well as being important carbon sinks and rich in biodiversity, mangrove forests provide fuel and food for coastal communities.
The findings appear in the Proceedings of the National Academy of Sciences.
"Aquaculture has largely been held responsible for causing mangrove deforestation, particularly in countries like Thailand and the Philippines," explained co-author Daniel Richards from the National University of Singapore.
He told BBC News that a study of eight countries around the world between the 1970s and the early 2000s found that 54% of deforested mangroves were replaced with aquaculture ponds used for fish or shrimp/prawn production.
"Our study found that aquaculture was still important but we were surprised that in South-East Asia between 2000 and 2012, just 30% of deforested mangroves were replaced with aquaculture.
"The impact of other drivers, like rice and oil palm agriculture, was greater than we expected."
Mangroves - natural defences
•Mangroves are salt-tolerant evergreens that grow along coastlines, rivers and deltas
•Found in more than 120 tropical and subtropical nations
•The plants' root systems have been shown to dissipate wave energy
Dr Richards observed: "Almost 25,000 hectares of Myanmar's mangroves were converted to rice paddy between 2000 and 2012."
He added that while there had been a few previous studies that had highlighted the role of oil palm production as a cause for mangrove loss, they had no idea of the scale of the deforestation.
"Sixteen percent of all deforested mangroves in Southeast Asia were replaced with oil palm plantations during our study period," he said.
"We usually think of oil palm as an issue which affects tropical forests on land but our study shows that demand for oil palm is also driving deforestation in coastal mangrove forests."
'Very threatened'
Dr Richards and his colleague, Daniel Friess, used Google Earth to monitor how land was used once mangrove forests had been felled.
"We viewed [more than] 3,000 deforested mangrove patches, and recorded the land-use that they were replaced with," Dr Richards said.
"This study also builds on some great existing data sets that were provided by scientists at the University of Maryland and the US Geological Survey."
He warned that mangrove forests in the region were "very threatened":
"Our study focused on quite a recent period of time but mangroves in South-East Asia have experienced widespread deforestation for decades.
"Previous research suggests that around 90% of Singapore's original mangrove forests have been lost."
The region is home to about one third of the world's mangroves, including some of the most biodiverse.
The researchers said mangroves were important to people because they provide fish and crabs, wood and charcoal, and can help protect coastlines from erosion.
Mangrove forests also stored very high densities of carbon so had a role in regulating carbon in the atmosphere, they added.
In other regions, such as Sri Lanka, the value of intact mangrove forests has been recognised by authorities and measures have been put in place to protect them.
Growing awareness
Dr Richards said that the importance of mangrove forests is becoming better understood, but it was a slow process.
"It is encouraging that our study found low rates of mangrove deforestation in Vietnam, the Philippines, and Brunei, and this is partly due to stronger protection of mangroves in these countries.
"There are initiatives to restore mangroves in some countries: the Mangrove Action Project in Thailand, and Blue Forests in Indonesia, are working with governments and local communities to protect and restore mangrove forests."
But he warned that more needed to be done: "Indonesia has more mangrove forests than any country in the world, and the mangroves in the more remote parts of the country, such as Indonesian Papua, are almost intact.
"However, these mangroves may be at risk of deforestation [as a result of] recent plans to grant concessions and develop the agriculture industry in this region.
"If we want to protect Indonesia's remaining mangroves then we need to act quickly."
Land conversion threatens Southeast Asia's mangrove forests: NUS study
Continued expansion for rice farming in Myanmar and conversion of magroves into oil palm plantations in Malaysia and Indonesia could accelerate deforestation, according to researchers.
Channel NewsAsia 5 Jan 16;
SINGAPORE: The conversion of mangrove forests for other uses poses a big threat to their existence here in Southeast Asia, according to a study by National University of Singapore (NUS) researchers.
In a press release on Tuesday (Jan 5), NUS said that while the rate of deforestation was lower than previously thought, 2 per cent, or more than 100,000 hectares, of mangroves in the region were deforested from 2000 to 2012.
The study was authored by Assistant Professor Daniel Friess, from the Department of Geography at NUS, and Dr Daniel Richards, who was formerly from the same department. Dr Richards is now with the Department of Animal and Plant Sciences at The University of Sheffield.
According to the study, Southeast Asia has the greatest diversity of mangrove species in the world, which store substantially higher densities of carbon as compared to most other ecosystems globally. Thus, the mangrove forests play an "important role" in mitigating carbon dioxide emissions and climate change, the press release said.
"UNDER-RECOGNISED THREATS"
Despite the lower than expected rate of deforestation, the researchers found that continued agricultural expansion for rice in Myanmar and conversion of mangroves into oil palm plantations in Malaysia and Indonesia were "under-recognised threats" and may threaten the existence of the mangrove ecosystems in the region.
In Myanmar, rice expansion has accounted for more than a fifth of the total mangrove change in Southeast Asia over the study period, and these trends are likely to continue with the country's ongoing economic transformation, the press release said.
As for the development of oil palm plantations, this is already a "major driver" of terrestrial forest and peat swamp deforestation in Malaysia and Indonesia, and contributes to regional issues such as haze, the researchers said. With palm oil production in Indonesia expected to increase steadily over the next few years, especially into frontier areas such as Papua, this is likely to pose "severe threats" to the mangrove forests there, they added.
“Our study provides detailed information for evidence-based conservation of mangrove forests. Future research and policy interventions, at the national and subnational level, must consider the diversity of drivers of mangrove deforestation,” said Dr Richards.
The findings were published in the journal, Proceedings of the National Academy of Sciences of the United States of America, in December last year.
- CNA/kk
Plantations main cause of mangrove loss
The Star 6 Jan 16;
PETALING JAYA: Plantations are the top cause of mangrove deforestation in Malaysia, a National University of Singapore study found.
Covering Asean, the study found that Malaysia lost 18,836ha of mangrove forests from 2000 to 2012.
At least 38.2% of this was due to mangroves being converted to oil palm plantations.
Other notable causes of mangrove loss, the report found, were due to logging – legal or illegal – which was reflected in the study as mangrove forest regrowth (17.6%).
“Malaysia has quite a lot of mangrove regrowth,” Dr Daniel Richards, one of the paper’s two authors, told The Star in an email.
“A big chunk of mangrove regrowth occurred in the Matang Mangrove Forest Reserve in Perak.”
Oil palms and rice join aquaculture in destroying mangroves
Today Online 8 Jan 16;
SINGAPORE — Oil palms and rice plantations have been identified as key drivers of mangrove deforestation in South-east Asia in recent times, alongside the traditional culprit, aquaculture.
About 100,000 hectares of mangroves in South-east Asia were lost between 2000 and 2012, and a recent study by researchers linked to the National University of Singapore (NUS) found that about 22 per cent of that area was converted to rice agriculture, while 16 per cent was converted to oil palm plantations.
Rice agriculture expansion in Myanmar, especially in Rakhine state, as well as expansion of oil palm plantations in Malaysia, Sumatra and Borneo, are under-recognised threats to mangrove ecosystems, which offer coastal protection, are highly biodiverse and store disproportionately large amounts of carbon, said the researchers.
While the study confirmed aquaculture — the farming of fish and other aquatic creatures — as the main driver of mangrove destruction in the region, responsible for about 30 per cent of mangrove forests lost, its role was smaller than in previous decades.
During the 1980s and 1990s, as much as double the percentage of mangrove forest destroyed was estimated to be for fish or shrimp ponds, wrote researchers Daniel Richards and Daniel Friess in their paper published last month in the journal, Proceedings of the National Academy of Sciences of the United States of America.
Mangrove conversion to aquaculture now occurs mainly in Kalimantan and Sulawesi in Indonesia.
Assistant Professor Friess is from NUS’ geography department; his former colleague Dr Richards is now with the University of Sheffield.
The pair used global forest-change datasets and satellite imagery in their analysis, supported by Singapore’s Ministry of Education.
“This is the first study to systematically quantify the conversion of mangroves to different land use types in South-east Asia and identify the key drivers of mangrove deforestation over the past decade,” said Asst Prof Friess.
Available data potentially shows mangrove destruction slowing down, but the problem remains substantial, he said.
South-east Asia lost its mangrove forests at a rate of 0.18 per cent a year between 2000 and 2012, with the highest rates of loss found in Myanmar, Malaysia, Cambodia and Indonesia.
Singapore, whose mangrove forests make up about 0.5 per cent of its total land area from an estimated 13 per cent in the 1820s, did not suffer any mangrove loss from 2000 to 2012.
In future, mangroves will probably continue to be under siege in Myanmar and Indonesia — given few environmental safeguards for mangrove forests and the importance of rice production for food security in the Indochinese country, and future oil-palm expansion slated for Papua, said the researchers.
Besides mangrove loss, oil palm expansion has also been blamed for the drainage of carbon-rich peatlands, which has contributed to haze-causing forest fires.
The study could aid decision makers in formulating targeted, evidence-based policies to conserve mangrove forests, said the researchers.
Read more!
Posts
visitors since Nov 07