After 13000 B.C., wetlands played an important role in early civilizations. For prehistoric communities throughout the world they provided food, water, and materials for clothing, shelter, and tools. Wetlands are able to reveal many of these ancient civilizations' secrets to scientists. Bodies of animals and humans, and artifacts (objects made by humans, including tools, weapons, jars, and clothing) have been well preserved in some wetlands and give information about how ancient people lived. Evidence of these ancient communities has been found in bogs. Conditions in bogs are excellent for preserving artifacts and bodies.
Wetlands have had an affect on the supply of food and water, on shelter, and on other resources.
Food and water: Wetlands are a source of water for drinking and crops. Areas near wetlands also continue to provide food in a variety of ways for tribal cultures in Asia and Africa and for urban peoples elsewhere. Since wetlands are a habitat for much wildlife, hunting and fishing are common there.
Cattle can be raised near wetlands because water and grazing land are available. Crops such as sorghum (a cereal grain native to Africa and Asia) are commonly grown in wetland areas. Grain sorghums, such as milo, kafir, and durra, have adapted to the extremes of the wet/dry cycle of the wetland and are among the most drought-tolerant grains. Millions of people in China, India, and Africa rely on sorghum as a food staple. In the United States, sorghum is used mostly as livestock feed.
Besides sorghum, American farmers use wetland plants, such as marsh grass, reeds, and sedges, for feeding livestock. Wetlands are also an excellent place to grow rice, which is a major food source for much of the world's population.
Shelter: Materials for dwellings are also available from wetland sources. Roofs made from reeds are used on huts in Egypt and in stilt houses in Indonesia to keep the occupants cool and dry. A tightly woven reed roof can last for 40 years. House frames are constructed from the timber of mangrove, palm, and papyrus trees. Wetland sediments, such as clay and mud, may be used to produce bricks that are used for walls.
Other resources: Wetlands provide other resources that humans rely on besides building materials. For example, dried peat is used in homes for heat and to fuel electric generators in countries, such as Ireland, where coal is scarce. Peat is a source of protein for livestock feed, and chemically processed peat is used as a base for polishes and waxes. In horticulture, peat moss is used as groundcover, a soil conditioner, and a growing medium. Peat is also found in medicinal baths and cosmetics.
Other wetland soils are sources of gravel and phosphate. Phosphate is used as a raw material for making fertilizers, chemicals, and other commercial products.
About 25 percent of medicinal drugs come from plants, some of which grow in wetlands. The Madagascar periwinkle, for example, provides vineristine, an agent that has helped reduce the death rate of childhood leukemia.
The important role of the wetland for plant and animal communities and for the environment in general has not always been understood. For more than 2,000 years, people in different countries have been draining wetlands to get rid of mosquitoes and disease, to increase land for farming, and to make room for development. By 1990, more than half of the wetlands in the United States were destroyed, and more than 90 percent of bogs in the United Kingdom are gone.
As the value of wetlands becomes more recognized, government agencies, such as the U.S. Department of the Interior and U.S. Fish and Wildlife service, as well as environmental groups, are working to preserve existing wetlands and to create new ones.
The Convention on Internationally Important Wetlands was signed by representatives of many nations in Ramsar, Iran, in 1971. Commonly known as the Ramsar Convention, it is an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.
Use of plants and animals: When animals and plants are overharvested they become endangered. Overharvesting means they are used up and destroyed at a faster rate than they can reproduce. When this happens, wetland, timber, fuel, medicines, and sources of food for humans and animals are all lost.
Use of natural resources: The two primary resources found in wetlands are water and peat. Wetlands often act as part of the groundwater system. When they are lost, the supply of drinking water may be affected.
It takes twenty years for one inch of peat to form, and its overuse has caused significant peatland losses. Western European peat mining companies are rapidly using up local areas of peat and expanding their mining operations into eastern European countries. All natural peatlands or bogs in the Netherlands and Poland have been destroyed. Switzerland and Germany have only 1,250 acres (500 hectares) each remaining.
Quality of the environment: Wetlands are endangered by industrial and municipal (city) contaminants, by the accumulation of toxic chemicals, and from acid rain.
Acid rain is a type of air pollution especially dangerous to wetlands. It forms when industrial pollutants such as sulfur or nitrogen combine with moisture in the atmosphere and form sulfuric or nitric acids. These acids can be carried long distances by the wind before they fall either as dry deposits or in the form of rain or snow. Acid rain can significantly damage both plant and animal life. It is especially devastating to wetland amphibians such as salamanders, because it prevents their eggs from maturing.
Mining for minerals near a wetland can have a negative impact on the biome. Mercury, a poisonous liquid metal used in gold mining operations, often contaminates wetlands close to the mines. Mining operations also require a lot of water, and nearby wetlands may be drained.
The world's climate may be growing warmer because of human activity. If polar ice caps melt, there will be a rise in sea level. As this happens, more salt water will flood into coastal wetlands and increase the salinity not only of the wetlands but of rivers, bays, and water supplies beneath the ground. As these habitats change, animal and plant life would he affected, and some wetlands may be destroyed.
Artificial wetlands: Artificial wetlands are those created by humans. In 1989, U.S. president George Bush, asked that the United States work toward the goal of no net loss of wetlands. This means that if a natural wetland is destroyed by development, an artificial one must be built to replace it. However, creating a wetland is very difficult. All the right conditions need to be met, including a water source and soil that contains a lot of water but not much oxygen.
An artificial wetland that works quite well and is extremely valuable worldwide is a rice paddy. A rice paddy is simply a field that is flooded for the purpose of growing rice, a food staple for about 3,000,000,000 people — more than one half of the world's population. Some are flooded naturally, by monsoon (tropical) rains or overflowing rivers. Others are flooded by irrigation (watering). Mud dams and waterwheels are built to bring in and hold the water level at approximately 4 to 6 inches (10 to 15 centimeters) while the rice grows. Ninety percent of rice paddies are in Asia, especially China and India. However, some rice is also grown in Europe and the United States.
Artificial wetlands can also be found on the Arabian Peninsula, where they are used for water storage and sewage treatment. Other human-made wetlands have been created as winter homes for migrating waterfowl.
The Marsh Arabs of Iraq and the Nilotic peoples of Africa live in or near wetlands that provide most all of the resources they need.
Marsh Arabs of Iraq: The Mesopotamian wetland, one of the largest in the world, lies between the Tigris and Euphrates Rivers in southern Iraq. The Marsh Arabs, or Ma'dan, have lived there for more than 6,000 years. The water there is clean, calm, and fairly shallow — about 8 feet (2.4 meters) deep.
The Marsh Arabs' houses are made of reeds and built on islands that they also make. To construct the islands, they create a fence from reeds and partially submerge it. Then they fill the area inside the fence with cut rushes, add layers of mud, and stamp it all down. When the pile reaches the water's surface, they fold the top of the fence onto the pile and add more reeds to finish it. The completed island is big enough not only for the family to build a house and live on, but for their cattle as well.
Because their home is isolated from the outside world, the Marsh Arabs' way of life has remained the same for hundreds of years. Daily life consists of fishing, buffalo herding, and growing rice. Reeds are gathered every day to feed the buffalo. Transportation from house to house or to other villages is by means of small canoes called mashhufs.
The survival of the Marsh Arabs is threatened, however, by irrigation practices, which have drawn water from their wetlands. Some of the marshes have already been drained for agricultural use and oil exploration.
Nilotic peoples: The Nilotic peoples live near the Nile River or in the Nile Valley in Africa. Two Nilotic tribes, the Dinka and the Nuer, live in southern Sudan. This area is a rich floodplain, and during the wet season, from July through October, the people live on high ground in permanent villages. From December through April, when the floodwater recedes, they move to the floodplains. There, the Dinka build temporary villages right along the banks of the Nile River. Their homes, made from reeds and grasses, are circular at the base and come to a point at the top, much like a teepee. Their neighboring tribe, the Nuer, lives in a similar fashion but in the marsh, savanna (grassland), and swamp areas.
Wetland grasses and plants grow in the flooplain after the waters recede. The grasses provide food for cattle and also attract wildlife, which is often hunted for food. Nilotic tribes fish, hunt, and grow some grains. The Dinka use their cattle for meat and milk, but the Nuer will eat cattle only during religious ceremonies. For them, cattle represent wealth and are used for bridal dowries (gifts) and to sell. Animal hides are made into clothing and bedding, and dried cattle dung (waste) is used for fuel.
Source: "Wetland." U·X·L Encyclopedia of Biomes, Vol. 3. U·X·L, Detroit: 2000.