AAP Perth Now 15 Oct 15;
Mangrove forests across the Indo-Pacific could be under water by 2070, though Australian and New Zealand plants are well-placed to withstand the rising tide.
Even accounting for lower-than-expected sea-level rises in the coming years, many mangrove forests have a poor outlook, the study suggests.
Mangroves in Thailand, Sumatra, Java, Papua New Guinea and the Solomon Islands are predicted to be submerged within the next 45 years.
But it's brighter news for other Australasian mangrove hotspots.
"Our modelling shows mangroves are likely to persist in east Africa, the Bay of Bengal, eastern Borneo and north-western Australia," Queensland University Professor Catherine Lovelock said.
Areas with relatively large tidal ranges and more sediment are better prepared, she said.
The submerging of mangroves could have a significant economic effect with some forests valued at $US194,0000 ($A2.67 million) per hectare per year for their ecosystem services to fisheries, coastal protection and carbon sequestration.
"This is of particular concern as this region is expected to have variable but high rates of future sea-level rise," Professor Lovelock said.
The results of the study, undertaken at 27 sites across the Indo-Pacific, will be published in Nature.
Australia could lose mangroves to sea level rise, research warns
Sara Phillips ABC News 15 Oct 15;
Parts of Australia could lose their coastal mangroves to sea level rise before the end of this century, according to new research.
The loss of the quintessential coastal tree with built-in snorkels could have major knock-on effects for fisheries and nearby communities.
"Without mangrove forests, fish decline, there's reduced coastal protection, there's reduced coastal carbon sequestration," lead researcher Catherine Lovelock, who is a professor of biological sciences at the University of Queensland, said.
"Mangroves provide a whole range of ecosystem services."
In Australia, there are approximately a million hectares of coastal mangrove forests.
A rough estimate of the value of the services they provide to Australians has been put at $194 billion each year.
Australia has the second largest area of mangroves in the world, behind Indonesia. And it is not just Australia's trees that would be affected.
Calculations by Professor Lovelock and her team for the Indo-Pacific region showed that even with measures to control the release of climate-changing greenhouse gases, areas along the Gulf of Thailand, Papua New Guinea and the Solomon Islands could lose their mangroves in the next 50 years.
"We singled out the Mekong [River, in Vietnam] because it's one of the locations where mangroves are very important for people and it's also a river that has large dams proposed," she said.
"In the process of building dams, the sediment supply to the coast will be altered. That will be a negative for coastal systems. That will pose a problem in the future."
She said sediment washing off the land was usually trapped in the knotted roots of mangroves, building up soil as time goes by.
In most places in the world, mangroves accumulating soil in this way are expected to keep pace with sea level rise resulting from climate change.
But when sediments are reduced, the tidal flats that are usually home to the trees will gradually become inundated and become unsuitable for mangroves.
If there is development on the coast, the trees would have nowhere new to colonise, sealing their fate.
Mangroves in areas where there is only a small difference between high and low tide are especially at risk.
Professor Lovelock nominated Shark Bay in WA and around Adelaide as mangrove flats in Australia that are particularly vulnerable.
Mangroves in places such as north-western Australia, where the tidal range can be as much as 10 metres, are expected to cope even in scenarios with high sea level rise.
Loss of mangroves of concern to fishing community
Professor Lovelock said measuring rising sea level against accumulating sediment was all about finding a steady reference point. The technique is surprisingly low-tech.
"We go out into the mangroves with lots of stainless steel and hammer down rods that are connected to each other until they can't go anymore," she said.
"So we basically fix them into the sediment as deep as we can. Often that means hitting the rock surface that's below.
"And that forms this point deep in the sediment that we measure everything relative to."
Professor Lovelock said a loss of mangroves was particularly concerning for communities that rely on fishing for their livelihood.
"Mangroves are nurseries for some fish species. In some part of their life cycle, many fish species will use mangroves," she said.
"They might forage into mangrove forests when the tide is in... they are refuges for predation in some cases.
"Another good reason to conserve your mangroves is to stop CO2 emissions. Land use change accounts for 25 per cent of global CO2 emissions.
"And the destruction of mangroves and seagrasses and salt-marsh might actually contribute to that substantially because they're so carbon rich."
The research was published in Nature.
Rising seas will drown mangrove forests
UNIVERSITY OF QUEENSLAND EurekAlert 15 Oct 15;
Mangrove forests around the Indo-Pacific region could be submerged by 2070, international research published today says. Even with relatively low sea-level rises, many mangrove forests had a poor outlook said Professor Catherine Lovelock, a University of Queensland ecologist.
"Mangrove forests are particularly vulnerable," she said.
"Mangroves are predicted to be submerged in parts of Thailand, Sumatra, Java, Papua New Guinea and the Solomon Islands."
However the outlook in other parts of the world was more positive.
"Our modelling shows mangroves are likely to persist in east Africa, the Bay of Bengal, eastern Borneo and north-western Australia - areas where there are relatively large tidal ranges and/or higher sediment supply," said Professor Lovelock, who works in UQ's School of Biological Sciences and the Global Change Institute.
"Even in other areas though, the good news is that through accretion of sediment and maintenance of wetland soils, mangrove forests do have the capacity to avoid inundation and keep pace with sea-level rise."
Professor Lovelock said this was why there was an urgent need to plan for the maintenance of sediment supply in river systems that were likely to be dammed or heavily modified in future.
"The Indo-Pacific region holds most of the world's mangrove forests, but sediment delivery in this region is declining, due to activities such as dam construction," she said.
"This is of particular concern as this region is expected to have variable but high rates of future sea-level rise."
Forest degradation had to be reversed because it reduced organic inputs to soils that was vital for mangrove survival, Professor Lovelock said.
Plans should be made for the landward migration of vulnerable mangrove forests to higher elevations.
"Intertidal mangrove forests occur on tropical and subtropical shorelines, and provide a wide range of ecosystem services - to fisheries, in coastal protection and in carbon sequestration - with an estimated value of $USD194,000 per hectare per year," she said.
"Sea-level rise could threaten the long-term sustainability of coastal communities and of valuable ecosystems such as coral reefs, salt marshes and mangroves.
Professor Lovelock said the researchers analysed trends based on data from an international network of 27 sites.
UQ's Global Change Institute and the Australian Research Council funded the project.
The vulnerability of Indo-Pacific mangrove forests to sea-level rise is published today in Nature.
###
Co-authors are from the US Geological Survey; National University of Singapore; Cambridge University; University of Wollongong; Ministry of Marine Affairs and Fisheries, Indonesia; National Institute of Water and Atmospheric Research, New Zealand; Macquarie University; Vietnam National University; and the International Crane Foundation, US.
Rising seas will drown mangrove forests
University of Queensland Science Daily 14 Oct 15;
Summary: Mangrove forests around the Indo-Pacific region could be submerged by 2070, international research says. Even with relatively low sea-level rises, many mangrove forests had a poor outlook according to an ecologist.
Mangrove forests around the Indo-Pacific region could be submerged by 2070, international research published today says. Even with relatively low sea-level rises, many mangrove forests had a poor outlook said Professor Catherine Lovelock, a University of Queensland ecologist.
"Mangrove forests are particularly vulnerable," she said.
"Mangroves are predicted to be submerged in parts of Thailand, Sumatra, Java, Papua New Guinea and the Solomon Islands."
However the outlook in other parts of the world was more positive.
"Our modelling shows mangroves are likely to persist in east Africa, the Bay of Bengal, eastern Borneo and north-western Australia -- areas where there are relatively large tidal ranges and/or higher sediment supply," said Professor Lovelock, who works in UQ's School of Biological Sciences and the Global Change Institute.
"Even in other areas though, the good news is that through accretion of sediment and maintenance of wetland soils, mangrove forests do have the capacity to avoid inundation and keep pace with sea-level rise."
Professor Lovelock said this was why there was an urgent need to plan for the maintenance of sediment supply in river systems that were likely to be dammed or heavily modified in future.
"The Indo-Pacific region holds most of the world's mangrove forests, but sediment delivery in this region is declining, due to activities such as dam construction," she said.
"This is of particular concern as this region is expected to have variable but high rates of future sea-level rise."
Forest degradation had to be reversed because it reduced organic inputs to soils that was vital for mangrove survival, Professor Lovelock said.
Plans should be made for the landward migration of vulnerable mangrove forests to higher elevations.
"Intertidal mangrove forests occur on tropical and subtropical shorelines, and provide a wide range of ecosystem services -- to fisheries, in coastal protection and in carbon sequestration -- with an estimated value of $USD194,000 per hectare per year," she said.
"Sea-level rise could threaten the long-term sustainability of coastal communities and of valuable ecosystems such as coral reefs, salt marshes and mangroves.
Professor Lovelock said the researchers analysed trends based on data from an international network of 27 sites.
UQ's Global Change Institute and the Australian Research Council funded the project.
The vulnerability of Indo-Pacific mangrove forests to sea-level rise is published today in Nature.
Co-authors are from the US Geological Survey; National University of Singapore; Cambridge University; University of Wollongong; Ministry of Marine Affairs and Fisheries, Indonesia; National Institute of Water and Atmospheric Research, New Zealand; Macquarie University; Vietnam National University; and the International Crane Foundation, US.
Story Source:
The above post is reprinted from materials provided by University of Queensland. Note: Materials may be edited for content and length.
Journal Reference:
Catherine E. Lovelock, Donald R. Cahoon, Daniel A. Friess, Glenn R. Guntenspergen, Ken W. Krauss, Ruth Reef, Kerrylee Rogers, Megan L. Saunders, Frida Sidik, Andrew Swales, Neil Saintilan, Le Xuan Thuyen, Tran Triet. The vulnerability of Indo-Pacific mangrove forests to sea-level rise. Nature, 2015; DOI: 10.1038/nature15538
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