31 Dec 2018 - First global coastline survey shows 16% of tidal flats lost between 1984 and 2016.
Coastal development and sea level rise are causing the decline of tidal flats along the world’s coastlines, according to research that has mapped the ecosystems for the first time.
Scientists from the University of New South Wales (UNSW) and the University of Queensland used machine-learning to analyse more than 700,000 satellite images to map the extent of and change in tidal flats around the globe.
The study, published in Nature, found tidal flat ecosystems in some countries declined by as much as 16% in the years from 1984 to 2016.
Tidal flats are mud flats, sand flats or wide rocky reef platforms that are important coastal ecosystems. They act as buffers to storms and sea level rise and provide habitat for many species, including migratory birds and fish nurseries.
Almost 50% of the global extent of tidal flats is concentrated in just eight countries: Indonesia, China, Australia, the US, Canada, India, Brazil and Myanmar
Nicholas Murray, the study’s lead author and a senior research fellow at the centre for ecosystem science at the University of New South Wales, said because tidal flats were often at least partially covered by water they had been difficult to monitor in the past.
“This is a big ecosystem,” he said. “It’s all over the planet and highly susceptible to threats but we haven’t known where they are, which has limited the ability to monitor them.”
The research team worked with Google and used its computing resources to analyse every satellite image ever collected of the world’s coastlines.