SYDNEY, May 13 (Xinhua) -- Researchers from Australia's James Cook University have revealed that 4,000 square kilometers of the world's tidal wetlands have been lost in the last 20 years, and showed that conservation efforts were balancing the scales.
The research, published in the Science journal and released to the public on Friday, analyzed more than 1 million satellite images taken over 20 years to chart the decline.
"We wanted to address that, so we developed a machine-learning analysis of vast archives of historical satellite images to detect the extent, timing and type of change across the world's tidal wetlands between 1999 and 2019," said lead researcher Dr. Nicholas Murray.
Globally, 13,700 kilometers of tidal wetland were lost, however. This was offset by 9,700 square kilometers reclaimed through conservation works.
Murray said that the team found that 27 percent of the lost and reclaimed wetland was due to "direct human activities" such as agricultural conservation, and all other changes were due to indirect factors such as extensive development along coastal areas, and the processes of climate change.
The team also found that the majority, about three quarters, of the change happened in Asia, where human activity on coastlands is more intense.
"Asia is the global center of tidal wetland loss from direct human activities," said Murray.
"These activities had a lesser role in the losses of tidal wetlands in Europe, Africa, the Americas and Oceania, where coastal wetland dynamics were driven by indirect factors such as wetland migration, coastal modifications and catchment change," he said.
Murray noted that over 1 billion people now live in low-elevation coast areas, and that maintaining the health of these ecosystems was crucial to them and all of humanity.
"Tidal wetlands are of immense importance to humanity, providing benefits such as carbon storage and sequestration, coastal protection, and fisheries enhancement," the expert said.
He said that the continued monitoring of how wetlands change, combined with robust conservation programs, would be crucial to managing this unique ecosystem. ■