BEIJING, Aug. 30 (Xinhuanet) -- It measures 6 cm in length at most, but it can be worth up to 20 yuan (US$2.40) a piece. But even more costly than the dumbfounding price of the worm-like fungus Cordyceps, or aweto, experts say, could be a deteriorating ecosystem in one of China's most ecologically vulnerable places, said China Daily on Monday.

    Up here, on the roof of the world, the Qinghai-Tibet Plateau is the source of the Yangtze, Yellow and Lancang (or Mekong) rivers.

    But it is also the source of a rare and treasured ingredient that has been used in Chinese medicine for thousands of years.

    Known as dongchong xiacao, the "winter-worm summer-herb" gets its name from its unique life cycle.

    Growing mainly in highland meadows at heights of between 3,000 and 5,000 metres above sea level, the worm comes from a fungus that spends its whole life cycle living off one host - in this case, a moth.

    It stays with the moth while it lives underground in the winter, then breaks through the soil in the summer to grow.

    The worm was thought by Chinese traditional doctors to improve people's immunity to all illnesses, which it why was and is still so highly prized.

    Caiji Lamo, 60, lives in the Yushu Tibetan Autonomous Prefecture in Qinghai, and says digging became rampant in the early 1990s.

    Yushu and its neighbouring Golog Tibetan Autonomous Prefecture claim the best aweto worms in the country, and as such bear witness to the worst devastation of mountain slopes where it is supposed to grow.

    Every year, from April to June, more than 100,000 diggers swarm to the meadows there for the golden collecting season. Eyes peeled to hunt the "soft gold," this digging army leaves behind it slopes peppered with numerous holes that disturb the fragile vegetation of the plateau, where soil can take 10,000 years to become one centimetre thick.

    "You didn't see so many people digging here years ago," says Lamo. "Local people have always dug for chongcao traditionally, but not on such a massive scale."

    The driving force behind the digging craze is money, says Qiuying Lanze, an official working for the prefecture government of Yushu.

    His remark is backed up by Jin Xingqi, an aweto worm dealer based in Xining, the capital of Qinghai. In the 1970s, the government-set purchase price for aweto worms was only 21 yuan (US$2.50) per kilogram, but the price has been soaring since the early 1990s, he says, to 42,000 yuan (US$5,060) per kilogram this year for top- grade herbs. In coastal cities in East China and Southeast Asia, Jin says, it can cost 4,000 yuan (US$481) more.

    Few diggers bother to refill the holes they make so the vegetation can grow back, and thus the meadows are destroyed, says Lei Jun, a farming official in Qumalai County of Yushu. He calculates that for every worm-herb, a digger has to turn over a minimum of 30 square centimetres' soil, which means all nearby plants are eradicated.

    Landscape experts say there is only one aweto worm for every square metre of meadow, and diggers have to guess under which plants the worm is likely to hide.

    If they misjudge, land is damaged needlessly.

    "The diggers are not confined to digging," Lei says. "They trample on grass to build their tents and cut down bushes for cooking fuel. This is disastrous in a place where the climate is severely cold and the air is extremely thin. If the ecosystem is spoiled, it may never revive."

    Although the aweto worm does regenerate and many believe it is a waste to leave the rare herb underground, Lei says the devastating digging leaves little chance for it to come back. "We are suffering a decline in the number of worm-herbs, and the individual bodies of aweto are shrinking," he says.

    There has not yet been a specific study into the environmental impact of aweto digging, but Lei says devastated meadows are showing scarcer and scarcer grass covering.

    Fragile ecosystem

    "Such damage to the vegetation in this critical area may trigger a deterioration of the mega ecosystem, because Yushu alone claims the sources of three major rivers that flow through more than half of China and several countries in Southeast Asia," warns Ma Shenglin, a researcher with the Qinghai Provincial Academy of Social Sciences, who has been charting ecological problems for years. "Any environmental change in this area may have a ripple effect."

    The Yellow River, the country's second longest and dubbed "the cradle of the Chinese civilization," stopped flowing at its source between December 2003 and April 2004. Although there is no evidence to suggest the digging caused it, Ma predicts that this will happen more frequently if the digging frenzy, which will inevitably lead to ecological deterioration, is not checked.

    To try and protect the fragile ecosystem of the Qinghai-Tibet Plateau, China in 2003 zoned an area of 150,000 square kilometres under the jurisdiction of Yushu and Golog prefectures as a State nature preserve. Three years even before the State move, the local governments of the two prefectures had issued a ban on aweto digging. The digging mania has still retained its momentum.

    One reason is that the local ban targeted outsiders coming to the area to dig and did not stop locals, Lei said.

    There were at least 60,000 diggers from outside the area in Golog alone this year, according to estimates by the local farming department. But without an indiscriminate ban on all digging, the mandate cannot be effective.

    Such a ban would be hard to enforce, says Qiuying Lanze of Yushu, because the herb has become a major income source for local farmers and herdsmen, and in fact could account for 70 to 80 per cent of an average farmer or herdsman's annual cash income.

    People who have a contract with the local government to farm land consider they may do as they choose on it, says Lei.

    "And to make even more money, they let people from other places pay to dig the herb on their land," he says. And this, local officials believe, has fuelled the digging mania.

    A ban would also drive diggers into other prefectures in Qinghai, spreading the damage.

    Baima, a herdsman in Gangca County in the Haibei Tibetan Autonomous Prefecture, 800 kilometres north of Yushu, says there never used to be many diggers there, but this year some 10,000 outsiders flocked to his hometown. "The government ban pales at the rocketing price of the worm-herb market," laments Lei. "It seems to lead to growing demand for it, which in turn boosts its market price even further."

    Wang Haining, a digger who travelled 800 kilometres from Ledu County in northern Qinghai to Qumalai, says digging at a high altitude, in defiance of the extreme cold and thin air, is a tough pursuit that no one would do except farmers and herdsmen. "I'm digging aweto to pay for my children's annual school fees and the family's daily expenses," he said.

    Director with Qinghai Province's supervision centre of grassland resources Han Kai says there is no point blaming inefficient management for the rampant digging. "It is quite simply a case of defining who should own the rights to aweto - the government as land owners, or the farmers and herdsmen as contractors of the meadows," he said.

    Han says the provincial legislature is considering implementing regulations to tame the digging for a more rational exploitation of these rare resources. The regulations are expected to take effect next year.

    Scientists are also working to find a way to ease the ecological pressure caused by the digging mania. More than 40 research institutes in China have tried to cultivate the worm-herb artificially, with agriculturists in Xining reporting they successfully bred one example in 1998.

    But difficulties in simulating the alpine environment in test-tube conditions have meant no further breakthrough, says Wang Hongsheng, an expert with the Qinghai Provincial Farming and Veterinary Academy.

    Before scientists are able to find a solution, the struggle between the need to feed people and the urge to preserve an already fragile ecosystem will continue.

    But while earnings at an environmental cost may temporarily fill people's wallets, warns sociologist Ma Shenglin, merciless human exploitation of natural resources will eventually throw people into the abyss of poverty anyway.

    (China Daily)