A new study, co-authored by Professor Gary Kendrick in The University of Western Australia's School of Plant Biology, has shown that seagrass loss rates around the world are comparable to those reported for coral reefs, tropical rainforests and mangroves - with potential negative impacts for the more than one billion people who live within 50km of them.
The first global study of its kind, entitled "Accelerating loss of seagrasses across the globe threatens coastal ecosystems", will be published in the prestigious journal Proceedings of the National Academy of Sciences of the United States of America next week.
By assessing more than 200 studies carried out on seagrass around the world, the authors found that seagrasses have been vanishing at the rate of about 110 square kilometres a year since 1980, and that 29 per cent of the known extent has disappeared since seagrass areas were initially recorded in 1879.
"Our report of mounting seagrass loss reveals a major global environmental crisis in coastal ecosystems, for which seagrasses are sentinels of change," they write. "More importantly, in contrast to coral reefs, which also herald environmental change but occupy a relatively small portion of the world's oceans, seagrasses are global in extent except for the highest polar regions. Coastal ecosystems are under pressure from coastal development; growing human populations; climate change; and ecological degradation.
"Seagrass meadows provide important ecosystem services, including an estimated US $1.9 trillion a year in the form of nutrient cycling; enhancement of coral reef fish productivity; a habitat for thousands of fish, bird and invertebrate species; and a major food source for endangered dugong, manatee and green turtle," they write.
The study argues that coastal ecosystems have recognised ecological and economic values. For example, seagrass meadows support commercial fisheries; subsistence fisheries that ensure the livelihood of entire communities; nutrient cycling; sediment stabilisation; and globally significant carbon sequestration. They also provide links to other marine habitats.
For a copy of the paper: https://www.pnas.org/