‘Unprecedented’ mangrove dieback worries scientists

By David Sigston
10 May 2016 (AAP) – Scientists are worried about an “unprecedented” dieback of mangroves in northern Australia and the link with large-scale coral bleaching of the Great Barrier Reef. The widespread damage to mangroves around the Gulf of Carpentaria has been highlighted at an international wetland conference held this week in Darwin. While a detailed scientific survey has yet to be undertaken, photographs revealed hundreds of hectares of mangroves dying in two locations along both the west and east coastlines of the gulf. Professor Norm Duke, spokesman for Australian Mangrove and Saltmarsh Network, said the scale and magnitude of the loss appears “unprecedented and deeply concerning”. Prof Duke said the damage was particularly alarming given this year’s severe coral bleaching of the Great Barrier Reef, as it appeared to correlate with extreme warming events in the region. Until more extensive research is done, the James Cook University professor isn’t sure if the mangroves are beyond saving but is warning more needs to be done. “Shoreline stability, and fisheries values, amongst other benefits of mangrove vegetation, are under threat,” he said. Prof Duke has called for increased monitoring of mangroves, particularly in the remote areas of northern Australia, so scientists can establish baseline conditions and isolate and manage any dieback. Australia is home to seven per cent of the world’s mangroves.

Mangrove dieback worries scientists

(James Cook University) – A James Cook University professor has warned that scientists are witnessing a large-scale dieback of mangroves in northern Australia. JCU’s Professor Norm Duke, spokesman for the Australian Mangrove and Saltmarsh Network, said the scale and magnitude of the loss appears “unprecedented and deeply concerning”. The extent of the damage came to light during an international wetland conference in Darwin. A detailed scientific survey is yet to be done, but Professor Duke said photographs were produced of hundreds of hectares of mangroves dying in two locations on the coast of the Gulf of Carpentaria – at Limmin Bight, in the Northern Territory and Karumba in Queensland. “Shoreline stability and fisheries values, amongst other benefits of mangrove vegetation, are under threat,” he said. Professor Duke said the phenomenon was especially alarming in light of the large-scale coral bleaching of the Great Barrier Reef, as it also appeared to correlate with this year’s extreme warming and climate events in the region. Preliminary observations were presented at this week’s Australian Mangrove and Saltmarsh Network Conference in Darwin, hosted by Charles Darwin University Research Institute for the Environment and Livelihoods (RIEL). Professor Duke said understanding of the scale of the mangrove loss is currently hampered by the critical lack of detailed shoreline monitoring, particularly in the remote areas of northern Australia. Professor Duke and conference delegates called for mangrove monitoring efforts to be scaled-up as a matter of priority, so scientists could establish baseline conditions of national shorelines, and quickly isolate and manage dieback events such as those seen in the gulf. He said the next step in the investigation into the Gulf of Carpentaria dieback would be to start field investigations to determine the cause and begin appropriate management measures. Mangroves and coastal wetlands take in 50 times more carbon than tropical forests by area. Australia is home to seven per cent of the world’s mangroves.

Contact

Professor Norm Duke, James Cook University TropWATER Centre, Spokesman, Australian Mangrove and Saltmarsh Network
M: 0419 673 366
E: norman.duke@jcu.edu.au
(Dr Duke is currently on the Gold Coast).

Large-scale mangrove dieback “unprecedented”