Human activity is destroying the habitat of the wild grey snub-nosed monkey, a critically-endangered species in southwest China's Guizhou Province, conservationists said Tuesday.

"Their habitat is now restricted to a 260-square-kilometer area in the Fanjingshan Nature Reserve," said Yang Yeqin, the reserve's chief. "Few monkeys are found outside the area these days."

Even in the quietness of the mountain area, human activity and its attendant pollution threatens the monkeys, Yang said.

"Many tourists travel to the nature reserve these days. Environmental pollution -- water pollution in particular -- poses a threat to the monkeys," he said.

When the reserve area becomes crowded, contagious diseases are more easily spread, another threat to the monkeys' health, said Yang. "Snub-nosed monkeys live in groups, and so contagious diseases spread quickly and can even endanger the species."

Last year, the reserve's management demolished an 80-bed mountain-top hotel because the garbage it produced polluted the monkeys' habitat.

The grey snub-nosed monkeys of Guizhou Province are the rarest of the three species of golden monkeys that inhabit China's Sichuan, Yunnan, Gansu and Hubei provinces.

Chinese scientists found groups of snub-nosed monkeys in the early 1980s. At the time, the species's population was estimated to be around 200. After years of protection, the population has expanded to around 850. But even that number is less than the wild population of giant pandas, which is estimated at around 1,600.