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

Wetlands have been systematically destroyed over the past 300 years like many natural habitats on the planet. Bogs, swamps and marshes have disappeared from maps and memory, having been drained, excavated and built upon.

Close to a reliable source of water and generally flat, wetlands have always been prime targets for building cities and farms. The drainage of its waterlogged soils has produced some of the most fertile agricultural land available.

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

Peatlands, a special type of wetland, store at least twice as much carbon as all the forests in the world.

The amount of Earth’s precious wetlands that have been lost since 1700 has recently been addressed by a major new study published in Nature. Previously, it was feared that up to 50% of our wetlands were gone. However, the latest research suggests the figure is actually closer to 21%, an area the size of India.

Some countries have seen much greater losses, with Ireland losing over 90% of its wetlands. The main reason for these overall losses was the drainage of wetlands for cultivation.


Wetlands are not wastelands

This is the most comprehensive survey of its kind. Researchers used historical records and the most recent maps to monitor land use globally.

Despite this, the new paper highlights some of the scientific and cultural barriers to studying and managing 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 every region and season. What is the right amount of humidity? Some classification systems list coral reefs as wetlands, while others argue that it’s too wet.

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

Wetlands have disappeared around the world in a different way

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

The United States, Central Asia, India, China, Japan and Southeast Asia are also said to have lost 50% of their original wetlands. It is these regional differences that have fostered the idea that half of the world’s wetlands have disappeared.

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

An organic tonic

Losing a few hectares of wetlands may not seem like much on a global or even national scale, but it is very serious for the nearby town which now floods when it rains and is catastrophic for specialist animals and plants such as curlews. and swallowtail butterflies, live there.

Fortunately, countries and international organizations are beginning to realize how important wetlands are locally and globally, with some adopting ‘net zero loss’ policies that require developers to restore any habitat they destroy. The UK has promised to ban the sale of peat-based compost to home growers by 2024.

Wetland habitats are being conserved around the world, often at enormous cost. Have spent more than 10,000 million dollars (8,200 million pounds sterling) in a plan of 35 years to restore the Everglades of Florida, a red única of subtropical wetlands, lo que lo convierte en el project de restauración ecological más grande y costoso of the world.

The creation of new wetlands is also underway in many places. The reintroduction of beavers to enclosures in Britain is expected to increase the country’s wetland cover, 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 boost wildlife in the area. A study showed that the number of local mammal species skyrocketed by 86% thanks to these fur engineers.

Sustainable drainage systems

Even the sustainable drainage system ponds developers are creating on the outskirts of new housing estates could see pocket wetlands appear in cities across the UK. By mimicking natural drainage patterns 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 loss of wetlands is 20% or 50%. What matters is that people stop thinking of wetlands as waste land, there for us to drain them and turn them into ‘useful’ land.

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

This article was written by Christian Dunn, Lecturer in Natural Sciences at Bangor University.


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