Wetlands shrinking

Posted: 26 March 2008

Wetlands capture and retain rainfall, and prevent valuable sediments from being washed into lakes and rivers. They add moisture to the atmosphere, which falls as rain and cools the environment. Despite their value to humanity, half the world's wetlands have been lost, with most of the destruction taking place over the past 50 years. Since these fecund areas harbour a wealth of wildlife, their loss has contributed directly to the erosion of biodiversity and species loss.

Mesopotamian MarshlandsClick here for graphics illustrating the decline in the Mesopotamian Marshlands from 1973 to 2000

Take the example of the United States. The lower 48 states have lost over half of their wetlands to development since independence was declared 200 years ago. Wetlands have been whittled away at a relentless pace - decreasing from 200 million hectares in 1780 to 100 million hectares in 2000 - a loss of 247 million acres. A total of 22 states have lost more than 50 per cent of their wetlands, while seven states - Indiana, Illinois, Iowa, Missouri, Ohio and California - lost over 90 per cent.

In some areas of Europe, such as France and Germany, 80 per cent of wetlands have been lost, mostly during the last century.

Wetlands are drained for agriculture, urban expansion and industrial development. They are also drained for urban expansion and industrial development, polluted by runoff from farms, factories and municipal wastes, paved over for roads, mined for peat and minerals, over-run by introduced, non-native specie, and grazed to death by domestic animals.

Ramsar Convention

In an effort to preserve the world's remaining wetlands of international significance, a global Convention on Wetlands was signed in Ramsar, Iran in 1971. It is the only environmental treaty for a particular ecosystem and was the first to link conservation with the sustainable use of natural resources.

Lake Butrint, Albania, a wetland site of international importance. Credit: RAMSARAs an inter-governmental treaty, it provides a common framework for national action and international cooperation for the preservation and management of wetland ecosystems. As of the beginning 2008, there were 158 signatories to the Ramsar Convention with 1,722 wetland sites protected. These total about nine per cent of the world's wetlands, or about 160 million hectares - an area larger than Portugal.

Originally intended primarily to protect waterbird habitat, the Convention's remit has broadened over the years to recognise wetlands, including coastal wetlands such as mangroves, coral reefs and seagrass beds, both for their biodiversity and the well-being of human communities.

The problem is many of these sites are themselves under threat from development pressures. Listing the site in the Ramsar Convention is no guarantee of protection. Many countries fail to fulfill their pledges and in many cases named sites are being damaged. One example is a site in Germany where an airport runway is being extended, other is an oil terminal in Georgia. Spain is planning 100 dams in its National Hydrological Plan which would inflict massive damage on the country's wetlands.

National governments need to back up their commitments with appropriate legislation and management systems.

For further information on wetlands, visit the websites of:
IUCN's Water and Wetlands Programme
Wetlands InternationalAn excellent report on wetlands from the Worldwatch Institute (Worldwatch Paper 170: Liquid Assets) by Sandra Postel, published in 2005 at US$7 plus shipping and handling, can be purchased through the Worldwatch website (www.worldwatch.org) or by calling 1.888.544.2303 (in U.S.) or 1.570.320.2076 (from overseas), or by faxing 570.320.2079.