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Earth has lost a fifth of its wetlands since 1700, but most can still be saved

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Wetlands have been systematically destroyed over the last 300 years like many of the planet’s natural habitats. Swamps, swamps and swamps have disappeared from maps and memory, having been drained, dug and built.

Because they are close to a reliable source of water and generally flat, wetlands have always been prime targets for building cities and farms. Drainage of its waterlogged soils has produced some of the most fertile farmland available.

But wetlands also offer some of the best natural solutions to modern crises. They can clean water by removing and filtering pollutants, displacing floodwaters, sheltering wildlife, improving our physical and mental well-being, and sequestering climate-altering amounts of carbon.

Peat bogs, a particular type of wetland, store at least twice as much carbon as all the world’s forests.

How much of Earth’s precious wetlands have been lost since 1700 has recently been addressed by an important new study published in Nature. Previously, it was feared that up to 50% of our wetlands could disappear. However, the latest polls suggest the number is closer to 21%, an area the size of India.

Some countries had much greater losses, with Ireland losing over 90% of its wetlands. The main reason for these global losses has been the drainage of wetlands for cultivation.

Wetlands are not wastelands

This is the most comprehensive investigation of its kind. The researchers used historical records and the most recent maps to monitor land use on a global scale.

Despite this, the new document highlights some of the scientific and cultural barriers to the study and management of wetlands. For example, even identifying what is and what is not a wetland is more difficult than for other habitats.

The defining characteristic of a wetland, being wet, is not always easily identified in all regions and seasons. How much is the correct amount of moisture? Some classification systems list coral reefs as wetlands, while others argue that this is too wet.

And for centuries, wetlands were seen as unproductive wasteland ready to be converted into farmland. This makes records of where these ecosystems used to be sketchy at best.

Wetlands disappeared from the world in a different way

The report clearly shows that wetland removal is not evenly distributed around the world. Some regions lost more than average. Around half of Europe’s wetlands are gone and the UK has lost 75% of its original area.

The US, Central Asia, India, China, Japan and Southeast Asia also lost 50% of their original wetlands. It is these regional differences that have promoted the idea that half of all the world’s wetlands have disappeared.

This disparity is somewhat hopeful, as it suggests that there are still many wetlands that have not been destroyed, particularly the vast bogs of northern Siberia and Canada.

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Losing a few acres of swamp might not seem like much on a global or even national scale, but it is very serious for the neighboring town that now floods when it rains and is catastrophic for specialized animals and plants, such as sandpipers and swallowtail butterflies, that live there.

Fortunately, countries and international organizations are starting to understand just how important wetlands are locally and globally, with some adopting “zero net loss” policies that force developers to restore any habitat they destroy. The UK has pledged to ban the sale of peat-based compost to hobby growers by 2024.

Wetland habitats are being conserved around the world, often at enormous cost. More than 10,000 million dollars (8,200 million British pounds) have been spent on a 35-year plan to restore the Florida Everglades, a unique network of subtropical wetlands, which makes it the biggest and most costly ecological restoration project of the world.

The creation of new wetlands is also underway in many places. The reintroduction of beavers into enclosures in Great Britain is expected to increase the wetland coverage of the country, bringing with it all the benefits of these habitats.

Beaver dams and the wetlands they create reduce the effects of flooding by up to 60% and can increase the area’s wildlife. One study showed that the number of local mammal species skyrocketed by 86% thanks to these furry engineers.

Sustainable drainage systems

Even sustainable drainage system ponds that developers create on the outskirts of new housing developments could see swamps appear in towns and cities across the UK. By mimicking natural drainage regimes, rather than removing surface water with pipes and sewers, sustainable drainage systems can create areas of plants and water that have been shown to increase biodiversity, especially invertebrates.

It does not matter whether the total global wetland loss is 20% or 50%. What matters is that people stop seeing wetlands as wastelands, so that we can drain them and transform them into “useful” land.

As the UN recently noted, approximately 40% of Earth’s species live and breed in wetlands, and a billion people depend on them for their livelihoods. Preserve and restore these vital habitats is the key to achieving a sustainable future.

This article was written by Christian Dunn, Senior Professor of Natural Sciences at Bangor University.


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