Miracle mangrove “land builders” adapt to ocean rise amid climate change

CIFOR scientist Daniel Murdiyarso at a research site in Secanggang, North Sumatra, Indonesia. CIFOR/Mokhamad Edliadi
Julie Mollins
20 June 2018

BONN, Germany (Landscape News) – Understanding how ecosystems function can help scientists develop strategies to ensure the planet will withstand the risks of climate change.

Mangrove ecosystems, recognized for their capacity to store large amounts of carbon and protect shorelines from erosion caused by rigorous ocean activity, also provide a buffer by capturing sediment high in organic carbon that can accumulate in tandem with sea level rise, according to research.

In a new study, scientists determined that sediment in mudflat, fringe and interior mangrove systems in Indonesia’s North Sumatra province accumulates at a rate of roughly 3.7 to 5.6 mm (an eighth to a quarter of an inch) each year.

They paired findings from test results with annual global and regional sea level rise rates of 2.6 to 4.2 mm respectively.

“Although mangroves can tolerate inundation resulting from tidal activity, they can be killed and their habitat destroyed if frequency and duration breaches their physiological threshold,” said Daniel Murdiyarso, a principal scientist with the Center for International Forestry Research (CIFOR), who conducted the study with a student from Indonesia’s Bogor Agricultural University and the country’s National Nuclear Energy Agency.

“Our results indicate that unless unpredictable sub-surface shifts occur, most mangrove ecosystems can keep apace with sea level rise — except for interior mangroves, which wouldn’t survive regional rise – they have a remarkable ability to adapt to climate change.”

Globally, the “land building” sedimentation rate of mangroves is between 1 and 10 mm each year. About 80 percent of sediment deposited by tidal activities is retained by the complex root systems of the trees.

“Natural regeneration should be promoted,” Murdiyarso said, adding that mangrove sediment can continue to play a key role in carbon sequestration – even as ocean levels rise.

The findings, which will be presented at the upcoming Blue Carbon Summit in Jakarta on July 17 and 18, show that regardless of immense environmental pressure in North Sumatra related to shrimp pond production, coastal oil palm plantations and a busy harbor port, mangroves can tough it out.

Despite their widely recognized significant climate change mitigation potential in international environmental policies aimed at reducing emissions from deforestation and forest degradation, known as REDD+ initiatives, mangroves are not yet included in Indonesia’s Nationally Determined Contributions (NDCs).

The need to implement NDC guidelines, which detail actions countries plan to take in efforts to address climate change risks with regard to both adaptation and mitigation — was established as part of the 2015 U.N. Paris Agreement on climate change.

The Paris pact stipulates that global temperature increases should be kept well below 2 degrees Celsius above pre-industrial levels. Goals also include pursuing efforts to limit the temperature increase to 1.5 degrees Celsius above pre-industrial levels to significantly reduce the risks from climate change.

A research paper published in the Proceedings of the National Academies of Sciences published earlier this year, said that at the current rate, the world’s oceans will be on average at least 60 cm (2 feet) higher by the end of the century.

Learn more about mangroves at Blue Carbon Summit in Jakarta on July 17-18, 2018. Click here.

Sign up for digital summit on blue carbon, July 11. Click here: Mainstreaming blue carbon to meet global commitments 

Find out more about restoration initiatives throughout Africa at the Global Landscapes Forum GLF Nairobi summit, August 29-30, 2018Click here

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