Global warming could destroy Tibetan economy

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Yujing Yan, Yi Li, Wen-Jing Wang, Jin-Sheng He, Rui-Heng Yang, Hai-Jun Wu, Xiao-Liang Wang, Lei Jiao, Zhiyao Tang, and Yi-Jian Yao. “Range shifts in response to climate change of Ophiocordyceps sinensis, a fungus endemic to the Tibetan Plateau,” Biological Conservation, Volume 206, February 2017, Pages 143-150. DOI: 10.1016/j.biocon.2016.12.023.

Tuesday, January 2, 2018

Rising sea levels and melting glaciers are certainly worrisome consequences of climate change — but there are more subtle changes that could also be disastrous. The geographical shift of caterpillar fungus, for example, could spell economic disaster for Tibetan people.

Global warming causes plants and animals to migrate to higher elevations, a phenomenon known as upward migration. Over 200 plants have shifted upward almost 30 meters every decade for the last century. In the 21st century, this pace is projected to accelerate around the world. The Tibetan Plateau is one of the regions most susceptible to global warming – and it is experiencing serious changes in the distribution of many of its plant and animal species. However, the most medicinally, ecologically, and economically concerning to the Tibetan people is an endemic fungal species called Yartsa Gunbu or Yartsa for short, which literally means summer grass winter worm. It’s also known as the caterpillar fungus. 

In 2016, a group of Chinese scientists from Peking University, Chinese Academy of Sciences and Fujian Agricultural and Forestry University published an article in Biological Conservation about the effect of global warming on the migration of Yartsa. The scientists collected field data about Yartsa for more than a decade and compiled their findings with weather data from 21 nearby National Weather Stations. They also collected records from 84 counties in Tibet and 12 different locations in Nepal that covered the majority of Yartsa’s natural habitats. Based on the data and the researchers’ models, the team predicted that potential habitat loss of Yartsa would reach 36.6 percent for the year 2050.

This particular fungal species is associated with larvae of ghost moth, which feeds on certain alpine plants. The ghost moths serve as hosts for the fungus. These moths have low migration rates and are unlikely to migrate to the predicted new habitats at higher elevations. In addition, other studies have shown that while species composition may have changed, vegetation type has barely changed on the Tibetan Plateau. As a result, the moths feed in the same range as before. However, global warming has caused the natural habitat of Yartsa to recede, but, unlike other plants and animals, this fungal species is not likely to move upward.

What does this mean to Tibetan economy? Yartsa has been used in both Chinese and Tibetan medicines for centuries. The fungus is believed to have healing qualities that benefit the lungs and kidneys. As China’s economy started to boom in the 1990s, the price of Yartsa increased. In the past two decades, its price has surpassed gold. Tibetans sell finer quality Yartsa at prices 3 or 4 times higher than the price of gold per kilogram.

Yartsa has become the most important source of income for many Tibetans. In Yartsa-rich communities, people only work during the harvest season from late May to late June and live off of what they earn for the rest of the year. Yartsa sale accounts for 70 percent to 90 percent of annual cash income in these communities. Daniel Winkler, a mycologist, assessed that Yartsa took up about 40 percent of the Tibetan economy in 2004. And unlike other monoculture products, this fungal species is difficult for human to cultivate. So if that number still holds true, losing 36.6 percent of its natural habitat would spell economic catastrophe for the Tibetan people.