At present, the wetlands in the world cover an area of 514 million ha. The area of wetlands in
Though the area of global wetlands occupies only 6 percent of the entire surface of the globe, the carbon concentration of the global wetlands makes up 35 percent of that of the terrestrial biospheres, and it is about 77 billion t, exceeding that of agricultural ecosystems of 15 billion t, that of temperate forest ecosystems of 15.9 billion t and that of tropical rain forest ecosystems of 42.8 billion t. The freshwater ecosystems like rivers, lakes and swamps, which only cover 0.8 percent of the surface of the earth though, possess 12 percent of the animal species in the world and 44, 000 recorded freshwater aquatic species, which take up 2.4 percent of all the known species in the world. The recorded fishes in the world are of 22, 000 species, of which the freshwater fishes are of 8, 400 species; the recorded freshwater algae in the world are of 25, 000 species; among the free-living protozoa in the world, the species living in freshwater are about 5 to 6 thousand in the world. In all the inland wetlands of our country including saltwater wetlands, the higher plants are of over 2,200 species alone (including the varieties), and the mammals are of 65 species, fertiles are of 50 species, amphibians are of 45 species, fishes are of 1,040 species and the wetland birds are of about 300 species.
According to the international study, the environment service values which the global ecosystem can provide are up to 3.33 billion dollars, the service values of which provided by wetlands are 490 million dollars, covering 14.7 percent of that provided by ecosystem.
The protected wetlands’ areas of all the countries can be seen in table 11-5, the form of conditions on the natural reserves in the world countries.