Yahoo News 3 Apr 11;
PARIS (AFP) – Mangroves, which have declined by up to half over the last 50 years, are an important bulkhead against climate change, a study released on Sunday has shown for the first time.
Destruction of these tropical coastal woodlands accounts for about 10 percent of carbon dioxide emissions from deforestation, the second largest source of CO2 after fossil fuel combustion, the study found.
Fewer trees not only mean less CO2 absorbed from the air, but also the release of carbon stocks that have been accumulating in shallow-water sediment over millennia.
Mangroves -- whose twisted, exposed roots grace coastlines in more than 100 countries -- confer many benefits on humans living in their midst.
The brackish tidal waters in which the trees thrive are a natural nursery for dozens of species of fish and shrimp essential to commercial fisheries around the world.
Another major "ecosystem service," in the jargon of environmental science, is protection from hurricanes and storm surges.
Cyclone Nargis, which killed 138,000 people in Myanmar in 2008, would have been less deadly, experts say, if half the country's mangroves had not been ripped up for wood or to make way for shrimp farms.
Daniel Donato of the US Department of Agriculture's Forest Service in Hilo, Hawaii and an international team of researchers examined the carbon content in 25 mangroves scattered across the Indo-Pacific region.
The trees stored atmospheric CO2 just as well as land-based tropical forests, they found. Below the water line, they were even more efficient, hoarding five times more carbon over the same surface area.
"Mangroves are among the most carbon-rich forests in the tropics," Donato and his colleagues said in the study, published in Nature Geoscience.
"Our data show that discussion of the key role of tropical wetland forests in climate change could be broadened significantly to include mangroves."
In a companion commentary, Steven Bouillon from the Katholieke Universiteit Leuven in Belgium said the carbon inventory uncovered by the study "provides a strong incentive to consider mangrove ecosystems as priority areas for conservation."
Study: Mangroves are vital carbon store
UPI 4 Apr 11;
HILO, Hawaii, April 4 (UPI) -- The world's coastal mangrove forests are capable of storing more carbon than almost any other forest on Earth, U.S. government scientist say.
Researchers from the U.S. Forestry Service research stations, along with scientists from the University of Helsinki in Finland and the Center for International Forestry Research in Indonesia, analyzed the carbon content of 25 mangrove forests across the Indo-Pacific region and found that mangrove forests store up to four times more carbon per acre than most other tropical forests around the world, a USFS release said Monday.
"Mangroves have long been known as extremely productive ecosystems that cycle carbon quickly, but until now there had been no estimate of how much carbon resides in these systems," Daniel Donato, a research ecologist at the USFS Pacific Southwest Research Station in Hilo, Hawaii, said.
"That's essential information because when land-use change occurs, much of that standing carbon stock can be released to the atmosphere," he said.
The mangrove forest's ability to store such large amounts of carbon can be attributed, in part, to the deep organic-rich soils in which the trees thrive, researchers said, and in fact mangroves have more carbon in their soil alone than most tropical forests have in all their biomass and soil combined.
"When we did the math, we were surprised to see just how much carbon is likely being released from mangrove clearing," Donato said, suggesting mangroves should be strong candidates for programs aiming to mitigate climate change by reducing deforestation rates.
Mangroves among the most carbon-rich forests in the tropics
Coastal trees key to lowering greenhouse gases
USDA Forest Service, Pacific Southwest Research Station EurekAlert 4 Apr 11;
HILO, Hawaii— Coastal mangrove forests store more carbon than almost any other forest on Earth, according to a study conducted by a team of U.S. Forest Service and university scientists. Their findings are published online in the journal Nature Geoscience. (www.nature.com/naturegeoscience.com)
A research team from the U.S. Forest Service's Pacific Southwest and Northern research stations, University of Helsinki and the Center for International Forestry Research examined the carbon content of 25 mangrove forests across the Indo-Pacific region and found that per hectare mangrove forests store up to four times more carbon than most other tropical forests around the world.
"Mangroves have long been known as extremely productive ecosystems that cycle carbon quickly, but until now there had been no estimate of how much carbon resides in these systems. That's essential information because when land-use change occurs, much of that standing carbon stock can be released to the atmosphere," says Daniel Donato, a postdoctoral research ecologist at the Pacific Southwest Research Station in Hilo, Hawaii.
The mangrove forest's ability to store such large amounts of carbon can be attributed, in part, to the deep organic-rich soils in which it thrives. Mangrove-sediment carbon stores were on average five times larger than those typically observed in temperate, boreal and tropical terrestrial forests, on a per-unit-area basis. The mangrove forest's complex root systems, which anchor the plants into underwater sediment, slow down incoming tidal waters allowing organic and inorganic material to settle into the sediment surface. Low oxygen conditions slow decay rates, resulting in much of the carbon accumulating in the soil. In fact, mangroves have more carbon in their soil alone than most tropical forests have in all their biomass and soil combined.
This high-carbon storage suggests mangroves may play an important role in climate change management. Aside from the main greenhouse gas contributor of fossil-fuel burning, the forestry sector can play a part—especially carbon-rich forests that are being cleared rapidly on a global scale, such as mangroves.
"When we did the math, we were surprised to see just how much carbon is likely being released from mangrove clearing," says Donato. This suggests, says Donato, that where consistent with local management objectives, mangroves may be strong candidates for programs aiming to mitigate climate change by reducing deforestation rates.
Recently, mangroves have experienced rapid deforestation worldwide—a 30 percent decline in the past 50 years. Mangrove deforestation generates greenhouse gas emissions of 0.02.12 petagrams of carbon per year, which is equivalent to up to 10 percent of carbon emissions from global deforestation, according to the research team's findings.
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The Pacific Southwest Research is headquartered in Albany, Calif. The station develops and communicates science needed to sustain forest ecosystems and other benefits to society. It has laboratories and research centers in California, Hawaii and the United States-affiliated Pacific Islands. For more information, visit www.fs.fed.us/psw/.
