There “ain't no mountain high enough”?: The drivers, diversity and sustainability of China's Rhodiola trade

Abstract Ethnopharmacological relevance Across Asia, Rhodiola species have been used in Bhutanese, Mongolian, Nepalese, Kazakh, Kyrgyz and Uzbek traditional medical systems. China is globally significant in terms of Rhodiola species diversity, with over 60% (55 species) of the world's 90 Rhodiola species, including 16 species found nowhere else in the world. Since the late 1980's there has been a shift from relatively low demand for infusions using chopped dried Rhodiola roots, to high 21st century demand for a wide variety of processed products. China's trade in Rhodiola products is now very diverse, with use in cosmetics and foods in addition to herbal products. Rhodiola crenulata (Hook.f. & Thomson) H.Ohba is the most widely traded species in China. In addition to R. crenulata and Rhodiola rosea L., 19 Rhodiola other species are used. Aims of the study These were to: (i) better understand why adulteration occurs in Rhodiola products; (ii) become more aware of what drives the growing market demand for Rhodiola products in China; (iii) find out whether increased demand is reflected in wholesale prices for Rhodiola raw materials traditional medicine markets; (iv) to examine Rhodiola supply chains and (v) given that wild populations are the primary supply source, to review the implications of growing demand for conservation and sustainable use. Materials and methods Firstly, we assessed growth in the diversity of Rhodiola products using three approaches: (i) by assessing patent applications for Rhodiola products in China (1990–2019); (ii) in 2018, through on-line searches of CFDA (China Food and Drug Administration) records for medicines and dietary supplements that had Rhodiola as an ingredient and (iii) by visiting retail stores in 2018 and 2019 to assess the diversity of commercial Rhodiola based products in trade. Secondly, we visited traditional medicine markets in Yunnan, Sichuan, and Qinghai provinces to investigate the trade in Rhodiola (folk taxonomy, trade names, prices, source areas, levels of processing and grading). Thirdly, we analysed the wholesale price data for Rhodiola raw materials in trade over a 16-year period (2002–2018). Fourthly, as most products come from wild collected Rhodiola species, we documented the extent of Rhodiola cultivation in China. Results International exports of Rhodiola products from China, particularly extracts, is a major driver of commercial trade. One proxy indicator of Rhodiola product diversification in China has been the rapid rise in patent applications from single applications in 1990 and 1991, to a peak of 1017 patent applications in 2015. Wholesale price data from 2002 to 2018 shows a steady increase in wholesale prices. As the growing market for Rhodiola products in China is currently supplied entirely from wild collection, there are justifiable concerns about sustainability. Commercial cultivation needs to expand to meet future demand. Conclusions In contrast to Europe and North America, where R. rosea is the focal species in commerce, the trade in Rhodiola products in China is much more diverse. In the face of growing demand, both effective conservation of wild populations and cultivation are needed.