Overexploitation and climate change threaten the Himalayan viagra
A parasitic fungus that infects moth larvae in the Himalayan region is one of the world’s most expensive biological niche commodities. Its prices have skyrocketed following the increasing demand of traditional remedies from urban dwellers, and the parasite has become essential for the livelihoods of hundreds of thousands of people in Asia. However, whether the production of the fungus is now in decline is not clear, nor what the reasons for decline might be.
To overcome the lack of quantitative observations and the high number of confounding factors, Hopping and colleagues used a ‘multiple evidence base’ approach. They combined local ecological knowledge gathered through interviews with harvesters with species distribution modeling based on information from the literature and from recent field studies. The authors reported a decrease in most of the fungus populations due to habitat degradation, climate change and overexploitation. Among collectors, over-harvesting was perceived as the main reason for decline, whereas the models pointed at the ongoing climate change effects as a major cause of the diminishing fungus production. Only the highest elevations in the region now host ideal habitats for the fungus to thrive, but it seems unlikely the parasite and the moth will be able to move upwards at the same pace as climate is changing. This study also highlights the usefulness of complementarity of different knowledge systems for assessing resource sustainability (PNAS 115, 11489–11494; 2018).
Because of the diversity of plant species the caterpillar host can feed on, and the variety of moth species the parasite infect, estimating the ecological impacts of a fungus population collapse is extremely challenging. However, the economical implications would be enormous for the communities who rely on the parasite as a resource.
Hopping, K.A., Chignell, S.M. and Lambin, E.F., 2018. The demise of caterpillar fungus in the Himalayan region due to climate change and overharvesting. Proceedings of the National Academy of Sciences, 115(45), pp.11489-11494. https://doi.org/10.1073/pnas.1811591115
