It will take at least 10 years to curb the desertification that is exacerbating erosion around the world's highest and largest wetlands, the Sanjiangyuan Nature Reserve, preservation experts have said.

Desertification has proven one of the worst ecological problems affecting the reserve in Northwest China's remote Qinghai Province, Li Xiaonan, an official in charge of wetland preservation in the reserve, said.

In 2005, authorities launched an ecological preservation project in the region to restore pastureland and move herders out of vulnerable areas.

"These measures have proven effective, but it will take about five years to restore the ecology and at least 10 years to curb desertification in the region," Li said.

Sanjiangyuan, which means "the source of three rivers", is the area where the Yangtze, Yellow River and the Lancang River originate.

The 363,000-sq-km area, located more than 4,000 m above sea level, is home to the world's highest wetlands.

But a 2003 national survey indicated there were 2.88 million hectares of sandy land at the origins of the Yangtze and Yellow River alone.

A group of scientists with the Qinghai-Tibet Plateau Study Institute of the Chinese Academy of Sciences warned the situation would continue to deteriorate because of climate change, overgrazing and increasing human activity.

Desertification is not only damaging the pastureland and hindering the development of the local animal husbandry industry, it also destroys water conservancy by burying waterways and speeding up evaporation, Li said.

The government has earmarked 16.5 billion yuan (US$2.2 billion) to protect and restore the wetlands during the 11th Five-Year Plan (2006-10).

(Xinhua News Agency September 18, 2007)