Medicinal plants are sometimes harvested in the wild, both in small quantities for personal use and in large quantities sold to companies that market herbal products to the public. The sustainability of this wild harvesting (or wildcrafting) depends on many anthropogenic factors, environmental context and species life-history traits.

Well-known examples of frequently wildcrafted herbs include American ginseng (Panax quinquefolius L.), black cohosh (Actaea racemosa L.), goldenseal (Hydrastis canadensis L.) and oshá (Ligusticum porteri J.M. Coult. & Rose).

In the U.S., harvest of wild medicinal plants, if not on private lands, occurs within the jurisdiction of the U.S. Forest Service. These plants are considered non-timber forest products. Managers of federal and other protected lands are often responsible for conserving populations of medicinally important plants.

Variable environmental conditions in which medicinal plant populations grow may influence their response to harvest, and thus the relative threat posed by harvest, which makes it difficult for land managers to develop generalized conservation strategies. Because strategies that work for American ginseng are unlikely to work for oshá, conservation planning for medicinal plant species requires an understanding of basic population structure under different environmental conditions to develop and implement customized sustainability strategies.

Oshá: A Case Study
This article explores the sustainability of oshá in order to demonstrate how sustainability efforts need to be customized for various species of wildcrafted medicinal plants. Oshá is an ethnobotanically important North American medicinal plant with large, pungent and distinctively spicy roots that are used traditionally to treat influenza, bronchitis and sore throat. Oshá roots are wild harvested by Native Americans, Hispanics, herbalists and other individuals for personal use and commercial sale by herbal product companies.

However, little is known about population structure, root production or the capacity of oshá to recover from harvest in different environmental contexts. Because oshá has historically been difficult to cultivate, and because of considerable consumer demand for its medicinal properties, the wildcrafting of oshá roots has raised concerns about sustainability. Oshá was proposed for inclusion, but has not been listed, on Appendix II of the Convention on International Trade in Endangered Species (CITES), an international treaty drawn up in 1973 to protect wildlife against over-exploitation. Oshá is listed as an at-risk species by the United Plant Savers, the only U.S. non-profit organization focused on medicinal plant conservation.

However, concern about declining oshá populations is difficult to substantiate, as oshá populations currently are not tracked by any state or federal conservation agencies. Additionally, there are no comprehensive management strategies in place for the conservation of this species.

The American Herbal Products Association’s (AHPA) Education and Research on Botanicals (ERB) Foundation has been funding a multi-year sustainability study on oshá to help inform conservation efforts of this valuable plant. In September 2012, the AHPA ERB foundation began funding research by Kelly Kindscher, PhD, of the University of Kansas to study the impact of wild collection on oshá populations.

The AHPA ERB Foundation research has gathered data on the location and inventory of oshá in the U.S., and is evaluating the sustainability of current harvest practices in southeastern Colorado and other locations, and developing best practices to ensure oshá is protected from over-collection and other threats that could limit the long-term viability of this plant species.

The research funded by the AHPA ERB Foundation has revealed key factors about oshá that can inform sustainability efforts. For example, the research found that canopy cover significantly reduced oshá growth, suggesting that oshá populations benefit from increased light availability. According to the research, average root weight per plant in meadow plots was three times higher than in forested plots. Lower canopy cover, and thus increased light availability, led to an increase in the count and cover of reproductive plants, the number of flowering stems, and the average root weight per plant. The abundance of vegetative plants, however, did not respond to canopy cover, indicating that light is most strongly influencing reproduction. Specifically, 72% of mature plants flowered in meadow plots, while only 60% flowered in the forest.

These results suggest that oshá population structure and root production are significantly influenced by canopy cover, but that plants have a high capacity for post-harvest re-colonization under variable light conditions. The results also demonstrate the need to account for environmental factors that influence population structure when addressing concerns about the overharvest of wild medicinal plants.

Open habitats with low canopy cover appear to promote reproduction and higher root biomass in oshá plants. The scarcity of seedlings observed across the canopy cover gradient suggests that recruitment is episodic, and that population recovery following harvest is mostly dependent upon vegetative re-colonization. Land managers should consider environmental variation in conjunction with harvest pressure when determining whether, how and where oshá populations should be permitted for harvest, and also where conservation should take priority.

This is the last year of the AHPA ERB Foundation’s current funding of this multi-year oshá harvest impact research project being conducted by Dr. Kindscher. Dr. Kindscher is requesting additional funding for follow-up work in 2017 and to help in the process to develop the oshá wildcraft permitting. If you would like to support this ongoing research, you can make a donation online.

Parallel to the research project, an AHPA Oshá Working Group is developing a manual on oshá best practices for harvesting techniques and conservation, and to explore the possibility of producing an accompanying visual presentation. AHPA’s hope is that the research and resources developed for oshá sustainability will provide a template for creating additional, customized sustainability strategies for other species of wildcrafted medicinal plants.

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Maged Sharaf, PhD
American Herbal Products Association (AHPA)

Maged Sharaf, PhD, is the chief science officer of the American Herbal Products Association (AHPA), the national trade association with a focus primarily on herbs and herbal products. AHPA’s membership represents U.S. and international growers, processors, manufacturers, marketers and institutes specializing in botanicals and herbal products. Before AHPA, Dr. Sharaf was the director, Foods, Dietary Supplements and Herbal Medicines at the United States Pharmacopeial Convention (USP). Before USP he was pharmacy associate professor and has preceding experience conducting bioanalytical assay development and validation, and human bioequivalence studies in support of the pharmaceutical industry; and quality control and manufacturing of pharmaceutical dosage forms. He can be reached at 301-588-1171; E-mail: msharaf@ahpa.org; Website: www.ahpa.org.