ABSTRACT
Wetlands are a major feature of the landscape in many parts of the world. They are among the most important ecosystems on Earth as they are the kidney of the landscape. Up to the mid-nineteenth century, wetlands were often given a sinister image. As a consequence of this view and the need for more agriculture land, wetlands have disappeared at alarming rates. They were drained and turned into agriculture land, which has resulted, particularly in the industrialized countries, in a massive pollution threat of pesticides and nutrient discharge by agricultural activities—a pollution that the wetlands and other natural ecosystems (ditches, trees, wind shelterbelts, ponds, forests, and so on) would otherwise eliminate. Today, the lack of many different small or big ecosystems as a pattern in the landscape has been a disaster for the abatement of the nonpoint pollution from agriculture. The various natural ecosystems are crucial for the health of the landscape.
