JOHANNESBURG - The destruction of the world's wetlands is exacerbating global disasters such as floods and famines and is a potential source of conflict in volatile regions, environmentalists said last week. "By a conservative estimate, about 50 percent of the wetlands worldwide are gone. These include rivers, swamps, marshes, small ponds, and mangrove systems," said Jane Madgwick, the chief executive officer of conservation group Wetlands International. "They are viewed as the most threatened ecosystems in the world and their degradation can amplify natural disasters and hurt the poor the most," she told Reuters by phone from the South African resort of St. Lucia, which is hosting a global conference on the issue. Last Thursday was World Wetlands Day.

The poor suffer the most because wetland loss often denies them access to safe drinking water or sources to irrigate their small plots, contributing to food insecurity. Wetlands have fallen prey to a range of practices, including being drained to make way for farmland or urban settlement. In developing regions such as Africa, the situation has been worsened by overgrazing and excessive burning. In South Africa's KwaZulu-Natal province where the conference is being held, this can be a spark for communal violence over scarce pasture land.

It has also contributed to floods in neighbouring Mozambique, where thousands of people were left homeless last month after heavy rains. The erosion of wetlands and overgrazing of grasslands on the upper watersheds of the Limpopo river in Botswana, Zimbabwe and South Africa channel raging waters into its lower watersheds or catchments in Mozambique and Malawi. Grasslands that are overgrazed are hardened, enabling water to flow over the ground and into rivers instead of seeping into the soil. Adding to the problem is the shrinkage of wetlands as these absorb excess water.

"Floods can be exacerbated by a hardening of surfaces which increases the runoff as the water does not soak into the grounds," said South African wetland ecologist David Lindley. He said the problems were global. More frequent floods and drought, blamed by some scientists on global warming but also linked to diminished wetlands, brought a near 20 percent rise in natural disasters in 2005. Wetlands are also a crucial habitat for countless species which vanish with them. In South Africa, the government has earmarked over $10 million annually to a project to restore degraded wetlands which also provides work to the rural unemployed. Reuters