Extensive coastal development along the East Asia coastline has led to rapid declines of tidal flat ecosystems, which are the principal coastal ecosystems protecting coastal populations in China Credit: Nicholas Murray
More than four thousand square kilometres of tidal wetlands have been destroyed worldwide in the last two decades, according to satellite pictures analysed by more than one million researchers.
Wetlands including tidal marshes, mangroves, and tidal flats around the world are rapidly changing as a result of global warming and human activity. Natural processes and ecosystem restoration, on the other hand, are helping to reduce overall losses.
Tidal wetlands, on the other hand, remain difficult to assess because of ambiguity about how they respond to changes in the environment.
Wetlands throughout the world are changing at an unprecedented rate, and researchers have built a machine-learning analysis of satellite photos from 1999 to 2019 to detect the extent, timing, and type of change.
More than 13,700 square kilometres of tidal wetlands were lost around the world during the two-decade period, which was offset by 9,700 square kilometres that were gained.
The findings were published in the prestigious scientific journal Science today.
Scientists at James Cook University’s Global Ecology Lab lead by Dr. Nicholas Murray found that 27% of gains and losses were directly linked to human activities such as agricultural conversion and restoration of devastated wetlands.
Direct human impacts on river catchments, coastal expansion and subsidence, coastal natural processes and climate change were blamed for all other changes.
Net global tidal wetland losses occurred primarily in Asia, with Indonesia, China, and Myanmar accounting for more than 70% of the losses in this region.
“The loss of tidal wetland habitat from direct human activity is concentrated in Asia. Wetlands in Europe, Africa, the Americas and Oceania, where wetland migration, coastal alteration, and catchment change were more important factors in the loss of tidal wetlands, were less affected by these activities “According to Murray.
According to the researchers, tidal wetland expansion, particularly in the Ganges and Amazon deltas, has compensated for about three-quarters of the global loss of tidal wetlands.
Tidal wetland expansion and natural regeneration are mostly the product of large-scale coastal processes, such as storm surges, tidal currents, and tidal currents.
According to Murray, “this result shows that we need to allow for the mobility and migration of coastal wetlands to account for rapid worldwide change”.
For successful management of changes in coastal habitats, he continued, “global-scale monitoring is now needed.”
Coastal low-lying zones currently host more than a billion people.
In addition to carbon sequestration, coastal protection, and fisheries enhancement, tidal wetlands are critical to human well-being.
“The well-being of coastal communities and the earth as a whole depends on the preservation of our coastal wetlands. Many plants and animals have nowhere else to go “According to research co-author and University of Cambridge Senior Research Associate Dr. Thomas Worthington,
“This data can assist identify coastal areas most impacted—and hence in need of protection, or areas where we should prioritise restoration,” he said.
Further information: Nicholas J. Murray et al, High-resolution mapping of losses and gains of Earth’s tidal wetlands, Science (2022). DOI: 10.1126/science.abm9583
Journal information: Science
Source: University of Cambridge