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Climate change, overfishing can spoil an expensive parasite



A parasitic fungus that grows wild in the Himalayas and sells for more than its weight in gold could disappear as the current crop and climate trends continue, according to a new Stanford University study.

  Handful of caterpillar fungus, with a box full in the background

High quality pieces of caterpillar fungus were sold in Beijing in 2017 for more than $ 140,000 per kilogram, more than three times as much as gold. The caterpillar fungus harvest has become a major source of income for hundreds of thousands of collectors in the remote high mountains where it grows. (Photo credit: Kelly Hopping)

The fungus Ophiocordyceps sinensis survives by capturing caterpillars of Ghostmoth in some of the highest regions of the Himalayas. The fungus infects and eats the inside of a caterpillar, which penetrates underground into the winter. What the parasite does next may be too scary to mention about an allegedly healing bowl of aphrodisiac soup (Price: $ 688), made in Las Vegas in fifteen minutes.

"It kills them and then sprouts their heads, like a unicorn," said lead author Kelly Hopping, an ecologist who conducted research as a postdoctoral fellow at the Stanford Earth, Energy, and Environmental Sciences (Stanford Earth).

Beginning in the 1990s, demand for mushroom as an aphrodisiac, anti-impotence drug, and cure for the deadly SARS virus helped – without scientific evidence – to spur global trade. Since then, belief in a wide range of beneficial effects of the fungus has spurred a $ 11 billion market, as well as concerns that crop yields have become unsustainable.

The official crop records, however, are unreliable, as many of the caterpillar fungus trade passes through illegal channels. This new study, published in the reviewed Proceedings of the National Academy of Sciences presents the most comprehensive data to date on whether and why caterpillar fungus production is declining and what consequences a possible crash will have the communities that rely on the fungus

Endangered Species and Livelihoods

Hop and study co-author Eric Lambin, a professor of Earth system science at Stanford, was interested in the mushroom as a way to understand what happens when a niche product gives affluent consumers an overseas influence on rural livelihoods, land use options and ecosystems in producer regions.

  Infected caterpillar grows from the ground

From May to June, collectors dig out infected caterpillars that are still associated with the fungus, typically before it begins to produce spores – a strategy that could damage population dynamics in the long term. (Photo: kelly hopping)

Ecosystem degradation research focuses on the expansion of globally traded agricultural commodities such as oil palm, soybean, livestock, and wood – the main drivers of deforestation. The wave effects of commodities that grow and trade on a smaller scale are less understood – but potentially profound, Lambin said. He refers to the rhino horn as an example.

"An emblematic mammal species is becoming extinct due to the demand for a product that is considered a virtue in some traditional cultures," said Lambin.

Caterpillar mushroom may lack the charisma of a rhinoceros, but as one of the world's most expensive biological raw materials, it has become a major source of income for hundreds of thousands of collectors. And at a time when up to a third of Earth's parasite species could die out in a matter of decades – which could open new niches for other invasive parasites – conservation biologists are increasingly seeing the need to protect parasites and their hosts.

According to Lambin, who is also a Senior Fellow at the Stanford Woods Institute for the Environment, there is no question that an intense harvest in an increasingly vulnerable landscape is affecting people and the environment. While many local collectors are trying to minimize impact, he said, large influx of people in the Himalayan areas during the Harvest Harvest can relegate degrading ecosystems through disturbing soils, shrubs and trees for fuel and waste to their crops

& # 39; Himalayan gold & # 39;

Widely known in Tibet as yartsa gunbu or "summer grass, winterworm", caterpillar fungus has been used in traditional medicine in the Himalayan region and in China for centuries to treat diseases ranging from cancer and kidney disease towards inflammation and aging processes. In recent years it has been nicknamed "Himalayan Viagra" and "Himalayan Gold".

To overcome the problem of patchy trade data for the valuable fungus, the team turned to collectors' knowledge of production trends in China, Bhutan, Nepal, and India, as reported in dozens of case studies. The researchers then confirmed the published reports by interviewing 49 collectors on the Tibetan Plateau.

Using these data and 400 records of where the fungus was found in the four countries since the 1970s, the group built models of how much fungus would grow in a given area based on factors such as climate and altitude. The results indicate that the fungus tends to be more productive in higher, colder areas around the edges of areas that have permafrost soils.

Warmer Winter

At present, the caterpillar fungus is plentiful in spring in major production areas, which many people may gather enough in a month or two to sustain themselves for the rest of the year. However, production is already declining due to the intense harvest – and warming winters could worsen this trend.

In a region where average winter temperatures have risen by as much as 4 degrees Celsius in some places since 1979 – "a tremendous warming," said Lambin – the researchers found that every degree of winter warming makes it harder for thrive the mushroom. When the permafrost disappears from the lower elevations, the fungus can adapt by shifting into colder, ascending habitats, only if its caterpillars – and the vegetation and seasonal patterns on which they depend – also shift upward.

In the long term, if income from caterpillar fungus can be sustained, the study suggests it could provide an important financial cushion for those whose livestock farming living on Hochalm prairie faced growing threats from climate change. "The caterpillar fungus collection has emerged as a way for people in these areas to make relatively easy money," Hopping said, "and in some cases, really increase their standard of living." However, reducing the environmental impact could exacerbate the tensions over access to the harvesting areas, Hopping said. English: www.cosmetic-business.com/en/showar…p?art_id=575. "Communities in areas where they are still growing need to remain alert to potential conflicts and poaching as humans seek to harvest this increasingly rare and valuable species."

Lambin is also the Prostial Professor of George and Setsuko Ishiyama. Hopping is now Assistant Professor at Boise State University College of Innovation and Design. Study co-author Stephen Chignell is now a Ph.D. student at the University of British Columbia.


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