For a long time, they were regarded by mankind as sterile, unhealthy, even dangerous places. Now, however, it is understood that wetlands are home to amazing ecosystems and a biological diversity that is almost beyond compare. Whether they take the form of salt marshes, mangroves, deltas, or peat bogs, these stretches of land shaped and dominated by water occupy some 6% of the planet’s continental landmass, an area of almost 2.3 million square miles (6 million square kilometers). They are found in the polar regions (the enormous Hudson Bay, for example) and in the tropics (the Okavango delta lies close to the Kalahari desert).
The density of species in wetland areas is very high. The Pantanal region of Brazil, at 77,000 square miles (200,000 square kilometers) is one of the largest in the world and is comparable to the nearby (and much more famous) Amazon rainforest. Some 3,500 species of plants, 400 fish, 300 mammals, and nearly 500 different reptiles have been identified here, with many as yet unrecorded, and the beauty of the landscape attracts naturalists from all over the world.
These places where land and water meet and mingle are under serious threat from human activity: they are being drained for farming, invaded by intensive aquaculture, redeveloped into industrial or commercial properties, and their area is shrinking at a startling rate. An international agreement known as the Ramsar Convention was signed in 1971 to protect wetlands, but as is often the case, there have been many obstacles to putting it into practice. Nevertheless, the last few years have seen a rise in awareness of the importance of wetlands to mankind, albeit primarily on an economic level. When well managed, these rich ecosystems can fulfill many functions: as well as being a potential source of fish and fodder, they can be developed into lucrative areas for eco-tourism. Wetlands are also able to store water—reducing the risk of drought—and can filter it too, acting as natural depollutants. All good reasons for ensuring their future protection.