A new report, launched on World Oceans Day, highlights the key role played by seagrass ecosystems in combating the climate crisis.
Professor Mark Huxham, of Edinburgh Napier’s School of Applied Sciences, was one of the contributors to Out of the Blue: The Value of Seagrasses to the Environment and to People.
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The report was released today by the United Nations Environment Programme (UNEP) together with GRID-Arendal and UNEP’s World Conservation Monitoring Centre (UNEP-WCMC).
Seagrass meadows can be a powerful nature-based climate solution and help sustain communities hard-hit by stressors such as the Covid-19 pandemic, but these important ecosystems continue to decline.
Among the most common coastal habitats on Earth, covering more than 300,000km2 in at least 159 countries, they nurture fish populations, weaken storm surges, and provide numerous other services to coastal communities.
Seagrass ecosystems are biologically rich and highly productive, providing valuable nursery habitats to more than 20 per cent of the world’s largest 25 fisheries. They can filter pathogens, bacteria, and pollution out of seawater, and are home to endangered and charismatic species such as dugongs, seahorses, and sea turtles.
But an estimated 7 per cent of seagrass habitat is being lost worldwide each year, and at least 22 of the world’s 72 seagrass species are in decline. Since the late 19th century, almost 30 per cent of known seagrass area across the globe has been lost. The main threats to seagrass meadows include urban, industrial, and agricultural run-off, coastal development, dredging, unregulated fishing and boating activities, and climate change.
Though they cover only 0.1 per cent of the ocean floor, seagrass ecosystems are highly efficient carbon sinks, storing up to 18 per cent of the world’s oceanic carbon. Countries aiming to do their part under the Paris Agreement can include seagrass protection and restoration in their nationally determined contributions (NDCs) to help reduce the amount of heat-trapping carbon in our atmosphere.
Edinburgh Napier's Professor Huxham said: “Seagrass meadows are ecological marvels. They provide food and habitat for turtles, in the tropics, and geese here in Scotland, and fish all around the world. They protect our shorelines from erosion and capture and store carbon. So it is time we worked to protect them. This report shows that we know how to do it and calls for governments, NGOs and individuals to get together and get to work on seagrass conservation.”
Professor Huxham also co-authored a related report, published by UNEP and formally launched today, which gives guidance to community groups on seagrass conservation.
Inger Andersen, Executive Director of UNEP, said: “As the world faces the double-whammy of an environmental and, global public health crisis, countries should embrace a range of actions and policies to halt the worrying decline of nature, including our often underappreciated but vital seagrass meadows.
“The Covid-19 pandemic has brought into sharp focus the devastating consequences of unsustainable environmental practices on the natural world and our global human community – intact and healthy ecosystems, including seagrasses, are a critical element of sustaining both planetary and human health.”
As the global community works to build back better and strengthen economies and societies in the wake of the devastation wrought by this pandemic, preserving and restoring seagrass ecosystems can be a highly effective way to protect food chains and create jobs in industries such as fishing and tourism.
The well-being of human communities all around the globe is closely tied to the health of seagrass meadows. In Tanzania, a decline in seagrass was found to have a negative impact on the livelihoods of women who collect invertebrates, such as clams, sea snails and sea urchins, from seagrass meadows. In the North Atlantic, seagrass provides critical habitat to juvenile Atlantic cod, a major commercial species that is fished by fleets from more than a dozen nations. Seagrasses are also part of the cultural fabric of many island communities. For example, in the Solomon Islands, fishers twist seagrass leaves together and shout to seagrass spirits for good luck.
Dr Maria Potouroglou, seagrass scientist at GRID-Arendal and lead editor of the report, said: “Seagrasses are the super ecosystems of our oceans, providing an incredible range of benefits to people around the world. Yet, while their flashier counterparts attract more attention, they remain among the most unheralded aquatic environments on Earth. The Out of the Blue report showcases the many ways that seagrasses help people thrive and sustain the healthy natural environment that we all depend on.”
Despite their importance, new data suggest that seagrasses are among the least protected coastal habitats. Only 26 per cent of recorded seagrass meadows fall within Marine Protected Areas (MPAs) compared with 40 per cent of coral reefs and 43 per cent of mangroves.