Conservation of North American Medicinal Plants Begins With Comprehensive Status Assessment

– Danna J Leaman, Co-Chair and Medicinal Plant Red
List Authority, Medicinal Plant Specialist Group, Species
Survival Commission, IUCN – International Union for
Conservation of Nature (
– Clayton Meredith, IUCN Red List Offi cer for Plants, New
Mexico BioPark Society
– Anne Frances, Lead Botanist and North American Plant
Red List Authority, NatureServe

Approximately 2,000 species of medicinal and aromatic plants are native to North America. The conservation status of these species is currently being assessed and updated by the IUCN Medicinal Plant Specialist Group and NatureServe, in partnership with New Mexico BioPark Society/ Albuquerque BioPark. Conservation status assessments will identify key threats to these species and their habitats, and support priorities for action to prevent resource decline and species extinction.


Native species of medicinal and aromatic plants comprise ten percent of the North American flora, and 0.05 percent of the known flora of the world. However, the North American native flora may provide nearly half of the medicinal and aromatic plants in global trade. Conservation, and sustainable use of this resource is therefore of great importance for the domestic and international supply of this resource.

The flora native to North America – considered in the Flora of North America to include the continental United States, Canada, the French islands Saint Pierre and Miquelon, and Greenland – comprises 20,000 species of vascular plants and bryophytes (Flora of North America, 2019), approximately 5% of the world’s known 400,000 plant species (World Flora Online, 2019). At least 2,000 of these species have reported historical or current medicinal uses. This estimate is derived primarily from two data sources: the Native American Ethnobotany database (Native American Ethnobotany, 2019) and the Medicinal and Aromatic Plants of the World (MAPROW) database (Schippmann, 2019).

Conservation Status of North American Medicinal and Aromatic Plants

The proportion of the world’s medicinal flora for which the IUCN Red List status is known is small, just seven percent of the nearly 30,000 taxa included in the MAPROW database. In partnership with NatureServe and the New Mexico BioPark Society, where a North American “hub” for Red List assessment, assessment training, and conservation planning has recently been established, North American members of MPSG and other regional experts have begun to identify North American medicinal plant species with a high priority for new or updated Red List assessments and subsequent conservation planning and action. The IUCN Red List has search functions that will enable evaluation of the degree to which medicinal plants in North America are threatened with extinction compared with other regions of the world, which types of threat are most significant for medicinal plants, need for additional research and conservation action, and types of conservation action that will be most eff ective. This initiative also supports updating NatureServe ranks for North American medicinal plants.

The conservation status of a majority of plant species native to North America has been evaluated at the continental, national, and state or provincial level by NatureServe, a non-government organization established in 1994 (NatureServe, 2019). In North America, NatureServe compiles and analyzes species distribution and other population data from a network of partners, including state-supported natural heritage programmes throughout the United States, and provincially supported natural heritage conservation bodies throughout Canada. The conservation status of a species is expressed by NatureServe as a rank, or a range of rank values, that indicate the severity of the threat of extinction to the wild population, ranging from “presumed extinct” to “secure” (Table 1).

The IUCN Red List is organized and published by the International Union for Conservation of Nature (IUCN) with assessments contributed by a large network of expert specialist groups, Red List authorities, and Red List partners (IUCN, 2019a). It is considered to be the global standard for conservation status assessments; for example, the IUCN Red List is the official indicator of progress on Target 15.8 – Life on Land – of the global Sustainable Development Goals (IUCN 2019b). Red List assessors assign a category of extinction risk using a rule-based system of criteria and thresholds that accommodate both data-poor and data-rich species. Assessment categories and criteria are applied on a global scale (IUCN, 2012a), with adjustments for nationaland regional-scale applications (IUCN, 2012b).

Both systems enable assessors to objectively apply rules for conservation status assessments, but also allow assessors to adjust the calculated rank or threat category.

The North American Medicinal and Aromatic Plant Assessment Project

In early 2018, IUCN Species Survival Commission (SSC) began a partnership with Albuquerque BioPark (Albuquerque, New Mexico) and funded through the New Mexico BioPark Society to develop staff capacity for conservation status (IUCN Red List) assessment and conservation planning. Clayton Meredith is working with the IUCN SSC Medicinal Plant Specialist Group on North American medicinal plant Red List assessments.



This project is part of the broader IUCN Plants for People initiative (IUCN 2019c). In 2019 and early 2020, with additional support from numerous experts, we completed draft Red List assessments for more than 60 species of North American medicinal plants, including 42 species in the genus Trillium, 15 species in the genus Ligusticum, and 17 species found only in the American southwestern “Borderlands” within and surrounding New Mexico. Included in these assessments are numerous species identifi ed by MPSG as high priorities for global assessment of extinction risk. Our high priority list currently focuses on medicinal and aromatic plant species included in the Convention on International Trade in Endangered Species of Fauna and Flora (CITES 2019), species included in the World Health Organization’s series of monographs on medicinal plants of global importance (WHO 1999, 2002, 2007, 2009), and species included in the United Plant Savers’ “At Risk” and “To Watch” lists (United Plant Savers 2019).

What happens next?

We aim to produce or revise conservation status assessments for all North American species of medicinal and aromatic plants (ca 2,000) by 2022, with a broadening base of institutional, expert, and funding support for assessments and conservation planning/ action.

Our plans for 2020 and onward include:

1. Publication of a comprehensive list of the approximately 2000 North medicinal plant species native to North America
This list is derived by comparing species included in the Flora of North America with the MAPROW (Medicinal and Aromatic Plants of the World) database that is managed by Uwe Schippmann, former Chair of MPSG. MAPROW incorporates key North American sources such as the Native American Ethnobotany database compiled by Dan Moerman and the American Herbal Products Association’s Herbs of Commerce (McGuffin et al. 2000), as well as many global and regional pharmacopoeias and other sources. This comprehensive North American list will be available on-line as an open-access resource, to engage MPSG members and the wider interested expert community and public in identifying additional priorities, resources, and expertise for IUCN Red List assessment of extinction risk, as well as in identifying errors and gaps.

2. Expert review of draft assessments
We will be reaching out to members of MPSG and beyond for assistance in reviewing draft assessments. A few North American MPSG members have undergone training in application of the IUCN Red List criteria; others have expertise in particular taxa or regional floras. We encourage you to let us know if you are willing to review draft assessments and/or undertake training to become an IUCN Red List assessor. An online training package is available to anyone interested, and training workshops may be available through ABQ BioPark in 2020.

3. Conservation Assessment workshops
We plan to continue a series of workshops to review draft Red List assessments in several regions of North America with significant medicinal plant diversity. The fi rst workshop, held in July 2019, focused on medicinal plant species that occur in the Southwestern United States including and bordering New Mexico. The second workshop, hosted by Mount Cuba Centre in Delaware, USA, focused on all Trillium species native to North America. Additional workshops will likely focus on species that occur in Southern Appalachia, Great Lakes, and Pacific Northwest regions.

We employ methods developed by the IUCN Conservation Planning Specialist Group to ensure that outcomes of these workshops include recommended conservation action, as well as an understanding of extinction risk for North American medicinal plant species.

4. Fundraising and new partnerships
We are working with New Mexico BioPark Society, NatureServe, and IUCN SSC to access additional sources of funding for this initiative.

Learn more:

Plants for People – Medicinal Plants – in other regions

We’re exploring additional Plants for People initiatives focusing on medicinal plants native to Latin America and the South Pacific, based on interest and enthusiasm of MPSG members and potential partnerships. We know that other regions are exceptionally important for medicinal plant conservation and encourage you to let us know about opportunities for developing Plants for People – Medicinal Plants – partnerships in your region.


Some of the content of this article is extracted from Leaman (in press).


  • CITES (2019) How CITES works. Convention on International Trade in Endangered Species of Fauna and Flora (CITES). Accessed 21 Aug 2019
  • Flora of North America (2019) Introduction. Accessed 17 Aug 2019
  • Frances A, Khoury C, Smith A (2019) Conservation status and threat assessments of crop wild relatives. In: Greene S, Williams K, Khoury C, Kantar MB, Marek L (eds) Crop wild relatives of North America. Springer, Dordrecht (in press)
  • IUCN (2012a) IUCN Red List categories and criteria: version 3.1, second edition. International Union for Conservation of Nature (IUCN), Gland, Switzerland and Cambridge, UK. Accessed 23 March 2018.
  • IUCN (2012b) Guidelines for application of IUCN Red List criteria at regional and national levels, version 4.0. International Union for Conservation of Nature (IUCN), Gland, Switzerland and Cambridge, UK. Accessed 21 August 2019
  • IUCN (2019a) The IUCN Red List of Threatened Species. Version 2019-2. Accessed 25 Nov 2019.
  • IUCN (2019b) SDG 15. Accessed 21 January 2020.
  • IUCN (2019c) Plants for People. Accessed 20 January 2020.
  • Leaman, DJ (in press). Diversity, Conservation, and Sustainability of North American Medicinal Plants. In A. Má the, ed, Medicinal and Aromatic Plants of North America. Springer Nature, Switzerland.
  • Native American Ethnobotany DB (2019). Available via Accessed 21 Aug 2019
  • NatureServe (2019) Our history. Accessed 21 August 2019
  • Oliver LE, Leaman DJ (2018) Protecting Goldenseal: how status assessments inform conservation. Herbalgram 119:40-55
  • Schippmann, U (2019) Medicinal and aromatic plants of the world (MAPROW) database. Not available online
  • United Plant Savers (2019) Species At-Risk list. Accessed 21 Aug 2019
  • Westwood M, Frances A, Man G, Pivorunas D, Potter KM (2017) Coordinating the IUCN Red List of North American tree species: a special session at the USFS gene conservation of tree species workshop. In: Sniezko RA, Man G, Hipkins V, Woeste K, Gwaze D, Kliejunas JT, McTeague BA (tech cords). Gene conservation of tree species—banking on the future. Proceedings of a workshop, Gen Tech Rep PNW-GTR-963. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, OR, pp 12-23
    – WHO (1999) WHO monographs on selected medicinal plants, volume 1. World Health Organization, Geneva
    – WHO (2002) WHO monographs on selected medicinal plants, volume 2. World Health Organization, Geneva
    – WHO (2007) WHO monographs on selected medicinal plants, volume 3. World Health Organization, Geneva
    – WHO (2009) WHO monographs on selected medicinal plants, volume 4. World Health Organization, Geneva
    – World Flora Online (2019) World Flora Online Consortium. Accessed 21 Aug 2019