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Climate change, overheating can make an expensive parasite

A parasite sponge that grows wild throughout the Himalayas and sells for more than its weight in gold can disappear…

A parasite sponge that grows wild throughout the Himalayas and sells for more than its weight in gold can disappear if current harvest and climate trends continue, according to recent research from Stanford University.

High quality caterpillar mushrooms sold for more than 140,000 dollars per kilo in Beijing in 2017, more than three times the price of gold. Harvest of larvae has become a primary source of income for hundreds of thousands of collectors in remote, high mountains where it grows. (Image Credit: Kelly Hopping)

The mushroom, Ophiocordyceps sinensis survives by preying on ghost moth larvae in some of Himalayas highest reach. The fungus infects and eats the inside of a larva that digs underground for the winter. What the parasite does next can be too cruel to mention over a probably leaking bowl of aphrodisiac soup (price: $ 688) made in Las Vegas with just a quarter of a gram of the stuff.

“It kills them and runs out of their head like a unicorn corner,” said lead author Kelly Hopping, an ecologist who conducted the postdoctoral research at Stanford Earth School, Stanford Earth.

From the 1990s the mushroom was requested as an aphrodisiac, impotence and cure for the fatal SARS virus – without the support of scientific evidence – helped to skip global trade. Since then, belief in a wide range of healthy effects from the fungus has encouraged a market like valued at about $ 11 billion, as well as concerns that the harvest has become untenable.

Official harvest records are unreliable, as much of Caterpillar mushroom trade goes through illegal channels. This new study, published in the Scientific Review Proceedings of the National Academy of Sciences present to date the most comprehensive information about whether and why caterpillar sponge production may decrease and the likely consequences of a possible crash for the communities that depend on the fungus for their livelihood.

Art and Life Danger in Danger

Jump and study co-author Eric Lambin, a Stanford Professor of Earth Systems Science, became interested in the fungus as a way to understand what happens when a niche biologic product gives rich consumers a major influence over rural livelihood , land use choices and ecosystems in producer regions.

From May to June, collectors collect infected larvae with the fungus still attached, usually before it begins to produce spores – a strategy that can harm the long-term dynamics of the population. (Image Credit: Kelly Hopping)

Ecosystem degradation research tends to focus on expansion of globally traded agricultural products such as oil palm, soy, cattle and wood – the main drivers for deforestation. The ripple effects of raw materials that grow and act on a smaller scale are understood less but potentially deep, Lambin said. He points to the Rhinoceros horn as an example.

“An emblematic mammalian species is put to extinction because of the demand for a product seen in some traditional cultures as virtues,” said Lambin.

Caterpillar fungus can lack the character of a rhino, but as one of the world’s most expensive biological raw materials, it has become a primary source of income for hundreds of thousands of collectors. And at a time when up to a third of the world’s parasitic species could be eradicated within a few decades – potentially open new niches for other invasive parasites to exploit – conservation biologists are increasingly looking for a need to protect parasites and their hosts.

According to Lambin, who is also a senior colleague at Stanford Woods Institute for the Environment, there is no question. Intensive harvesting takes a charge on both humans and the environment in an increasingly vulnerable landscape. While many local collectors try to minimize effects, he said that high inflows of people affected by the Himalayan field during the high season may endanger degrading ecosystems by disturbing fragile fields, cutting bushes and trees for fuel and leaving the trash around their crops

& # 39; Himalayan Gold & # 39;

Commonly known in Tibet as yartsa gunbu or “summerwood, wintertime” larvae has been used in traditional medicine throughout the Himalayan region and in China for centuries to treat diseases ranging from cancer and kidney disease to inflammation and aging. In recent years, it has been given the first name “Himalayan Viagra” and “Himalayan Gold”.

To address the problem of clever trade data for the valuable sponge, the team turned to collectors own knowledge of production trends in China, Bhutan, Nepal and India, reported in dozens of case studies. The researchers then reinforced the published accounts by interviewing 49 collectors across the Tibetan plateau.

With these data and 400 records of where the fungus has been found in the four countries since the 1970s, the group built models that predict how much fungus would grow in a certain area based on factors such as climate and height. The results show that the fungus tends to be more productive in higher, colder areas around the margins of areas underneath permafrost.

Warmer winters

Currently, the larvae sponge is rich enough in spring in the premier production areas that many people can gather enough in a month or two to support themselves for the rest of the year. However, production is already falling due to intensive harvesting – and heating winters can exacerbate this trend.

In a region where average winter temperatures in some places have already increased by as much as 4 degrees Celsius since 1979 – “a huge warming,” said Lambin researchers found that every degree of winter warming makes it more difficult for the fungus to thrive. Because permafrost disappears from lower heights, the fungus can adapt by changing to colder habitats only if its larvae are hosted – and the vegetation and seasonal patterns to which they depend – are also moved upwards.

In the long term, if revenue from Caterpillar fungus can be maintained, the study suggests that it could provide an important economic pillow for those whose livestock slaughter cattle on high-rise grasslands faces increased threats from climate change. “Caterpillar mushroom collection has emerged as a way for people in these areas to make relatively easy money,” Hopping said “and in some cases really raise their living standards.”

If demand continues to grow as deliveries decrease, it can exacerbate tensions over who has access to the harrows, Hopping said. “The communities in areas where it is still growing must be vigilant about potential conflicts and poaching when people try to harvest this increasingly rare and valuable species.”

Lambin is also George and Setsuko Ishiyama Provostial Professor. Hopping is now a deputy professor at Boise State University College of Innovation and Design. Study co-author Stephen Chignell is now a PhD student at the University of British Columbia.

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