Fears Northern Australian Mangrove Forests Could 'Drown' Due To Rising Seas

ABC News - Nick Hose

Northern Australia's mangroves could be under threat by rising sea levels. (ABC News: Nick Hose)

Key Points: Mangroves could be wiped out by the end of the century, researchers say Research is being done to work out how the ecosystem will cope with rising seas Sea level rise is happening at a faster rate in northern Australia than in the south

It's low tide on a sunny, dry season afternoon in the mangrove forest at East Arm in Darwin Harbour.
As the tide laps at the dense tangle of roots that run for thousands of hectares along northern Australia's pristine coastline, it's hard to comprehend these forests could be wiped out by the end of the century.
"They're definitely vulnerable," said Madeline Goddard, a PhD candidate at Charles Darwin University.
Ms Goddard is studying mangroves to see how they will adapt to rising sea levels.

Mangroves could drown
"Across the world the sea level is rising, increasing the amount of time mangroves spend underwater, potentially flooding and killing these valuable forests," Ms Goddard said.
The Bureau of Meteorology has been monitoring sea level rise and found it is happening at a faster rate in northern Australia than in the south.
"We've seen for the last 7,000 years the water level has slowly risen and that mangroves have persisted, they are really resilient," Ms Goddard said.

"But they can't keep up with our really dramatic projected rise."

Charles Darwin University PhD candidate Madeline Goddard (right) studies mangroves in northern Australia (ABC News: Nick Hose)

 
It is a fear shared by the Australian Marine Conservation Society.
Northern Territory manager Jason Fowler said the mangroves could drown because sediment was accumulating slower than the rate that the sea level was rising.

"So the mangroves will literally run out of mud, slowly get flooded, and drown out," he said.

"We've already seen that mangroves are vulnerable to climate change after one of the worst instances of mangrove forest dieback struck Australia's Gulf of Carpentaria in the summer of 2016."

Carbon-storing superpowers
Ms Goddard said there was a huge amount of carbon that mangroves store in the mud.
"But also in the forest themselves," she said.
It's a superpower that could prove crucial in the fight against climate change.
"Mangroves store a lot of carbon — upwards of 50 times more than identical areas of rainforest," Ms Goddard said.

Mangroves in northern Australia are under threat. (ABC News: Nick Hose)

 
Best hope of survival could lie in careful planning
Ms Goddard said mangroves might be able to adapt to sea level rise if they have space to grow.

"What's really critical is they can also move landward," Ms Goddard said.

She said many coastlines in northern Australia were not developed, which would leave new habitat for mangroves to move into.
"As you get elevated sea level rise you get increased flooding times, and so the area behind the mangroves has potential for them to move into," she said.

Links

• Extreme weather explains 'unprecedented' mangrove deaths: study
• 'Shocking images' reveal death of 10,000 hectares of mangroves
• 'They Died Of Thirst': Extreme Conditions Wipe Out Forest Over 1000 Kilometres
• 'Shocking images' reveal death of 10,000 hectares of mangroves across Northern Australia
• Mexican desert mangroves – small but valuable in dealing with climate change
• Extreme weather likely behind worst recorded mangrove dieback in northern Australia
• Rising seas threaten to drown important mangrove forests, unless we intervene