Alarm as mangrove recovery is derailed

WHILE mangrove forest near Cairns appears to be thriving, mangroves in the Gulf of Carpentaria are not faring as well.

Scientists investigating the mangrove dieback in the Gulf of Carpentaria from three years ago have found the coastal stretch of more than 1500km is struggling to recover. James Cook University researchers, led by Dr Norman Duke from the university’s Centre for Tropical Water and Aquatic Ecosystem Research, returned to the 8000ha area southwest of Karumba in August. Dr Duke said the results were not promising, following losses of the foreshore forest ranging from 10-100 per cent in 2015-16.

“While there has been limited resprouting with seedling establishment and regrowth, the recovery looks like it’s being overwhelmed by erosion combined with physical scouring by masses of drift logs and branches from dead mangroves,” he said. “Each high tide, dead material scrapes across the seedlings, breaking and killing them.”

The coastal mangrove dieback was believed to have been caused by five years of belowaverage rainfall, and a drought in 2015-16. This was worsened by record-level temperatures in the area, which left mangroves high and dry as the sea level dropped about 20cm during a very strong El Nino.

Charles Darwin University researcher Professor Lindsay Hutley said the dieback was regarded as the largest recorded incident of its kind.