Beijing (PTI): Global warming could trigger a dramatic decline in diversity of plant species on the rangelands in the Qinghai-Tibet plateau in southwest China, American and Chinese scientists warned, as research showed a 26 to 36 per cent drop in plant species from 1998 to 2001.

Experts said global warming specifically caused loss of 21 per cent of medicinal plants and 25 per cent of pasture plants.

Research into climate change and grazing in northeastern Qinghai-Tibet plateau had shown the decrease in plant species, Julia Klein, a US Colorado State University Assistant Professor who led the research said.

The experts warning came at a joint meeting of the International Rangeland Congress and the Internatonal Grassland Congress during their week-long meet at Hohhot, capital of Inner Mongolia Autonomous Region, which concluded on Saturday, official Xinhua news agency said.

The research was carried out at four sites at the Haibei Alpine Research Station where annual temperature is minus 2 degress Celsius and the elevation is 3,200 metres. Two sites were in grasslands and two in the shrubland habitats, which form about 35 per cent of the area in the plateau.

Researches simulated warming by using open top greenhouses and grazing through selective clipping. The greenhouses were left on the plots year-round, raising the average daily temperature by 0.6 degrees to 2 degrees celsius in the growing season. There were around 30 plant species in each.