Wetlands: "The Earth's kidneys"

Wetlands perform a number of functions, depending on their type and location:- they act as a sponge (storing, releasing and spreading water), limiting the intensity of flooding and run-off;- they filter and purify transiting water;- they act as a natural regulator: wetlands ensure good quality and quantity of water resources and limit natural and health risks;- they are a vital ecosystem for many species that depend on their existence. Wetlands are threatened environments: more than two-thirds of the surface area of wetlands in France disappeared in the 20th century, with 50% between 1960 and 1990.