Distribution and abundance of Hydrastis canadensis L. (Ranunculaceae) and Panax quinquefolius L. (Araliaceae) in the central Appalachian region1

Journal of the Torrey Botanical Society, Apr-Jun 2003 by McGraw, James B, Sanders, Suzanne M, Van der Voort, Martha

MCGRAW, J. B., S. M. SANDERS, AND M. E. VAN DER VOORT. (Department of Biology, West Virginia University, Morgantown, WV 26506-6057). Distribution and abundance of Hydrastis canadensis L. (Ranunculaceae) and Panax quinquefolius L. (Araliaceae) in the central Appalachian region. J. Torrey Bot. Soc. 130: 62-69. 2003.-As demand for goldenseal (Hydrastis canadensis L.) and ginseng (Panax quinquefolius L.) intensifies due to the herbal plant trade, basic information about distribution and abundance is needed to inform management strategies. We surveyed 16 sites focusing on West Virginia, but including nearby sites in Pennsylvania, Kentucky, Ohio, and Maryland to determine H. canadensis and P. quinquefolius presence and abundance. In total we surveyed 29.32 ha over two summers in a wide range of aspects, elevations, management regimes and forest cover types. So few patches of goldenseal were encountered that we were unable to detect statistically significant effects of elevation, aspect, land use or vegetation on either encounter probability or density. Ginseng was more frequently encountered than goldenseal. The probability of encountering ginseng increased with elevation. Overall, ginseng was not more frequent or abundant on north-facing 'cove' forests. A significant elevation x aspect interaction was found, whereby ginseng was most abundant on west-facing slopes at low elevation, but more abundant on east-facing slopes at middle elevations. Extrapolations of ginseng densities to the state of West Virginia suggest that the species is not rare in the typical sense. Instead, it is widespread, but scarce everywhere it is found. Harvest rates are estimated to be ca. 5% of the natural ginseng population annually. Understanding basic ecological relationships and management of these species is made difficult by the widespread, dispersed nature of individuals, patches and populations and the complex interaction with human harvesters.

Key words: Panax quinquefolius, ginseng, Hydrastis canadensis, goldenseal, rare plant distribution, central Appalachian, wild harvested plants, herbal plants.

Ginseng (Panax quinquefolius L.) and goldenseal (Hydrastis canadensis L.) are herbaceous perennial plants of the eastern deciduous forest, and are actively sought and harvested from the wild. They are sold on the herbal market where P. quinquefolius has commanded from $330/kg to $1,100/kg in recent years (Robbins 1998; 2000; Bailey 1999). The price of H. canadensis was $66.00/kg in 1998 (Bailey 1999). This demand provides a significant incentive for harvesters to dig plants from the wild, particularly in areas where unemployment is high (Bailey 1999). Although few sources document historic population levels (Davis 1976; Eichenberger and Parker 1976; Carlson 1986; Anderson et al. 1993), there is general agreement among biologists, natural resource managers and harvesters that abundance of these species is declining (Charron and Gagnon 1991; Catling and Small 1994; Sinclair and Catling 2000a). Both species are currently listed on Appendix II of the CITES treaty (Convention on International Trade in Endangered Species of Flora and Fauna). Therefore, the species must be monitored, and the federal government must certify that their harvest remains "non-detrimental" to permit international trade (Robbins 2000).

Little is known about the distribution and abundance of wild harvested plant species within their ranges (Anderson et al. 1993; Sanders and McGraw, 2002). Characterization of the environment where known populations occur can partially describe a species' niche (Anderson et al. 1993). With stratified random sampling, however, one can define the boundaries of the niche by learning where the species is absent, as well as where it is present.

The objectives of this study were twofold. First, we wanted to determine the mesotopographic distribution patterns of H. canadensis and P. quinquefolius near the center of their ranges. Specifically, we examined their presence and abundance among sites varying in aspect and elevation. Obviously, the present distribution and abundance may represent a shift from historical, preharvest distributions. Nevertheless, an understanding of the current distribution and abundance of these two species should clarify their realized niche breadth and thereby aid in their management as non-timber forest resources. Our second objective was to estimate roughly the density of P. quinquefolius across a representative area in the central part of its range (the state of West Virginia). Using this information, along with estimates of harvest over the past several years, we estimated the harvest pressure on wild ginseng populations. The rate of harvest is a key statistic for understanding impacts and sustainability of harvesting that was heretofore unknown.

Materials and Methods. P. quinquefolius is found throughout the eastern United States with the exception of the extreme south and southeast. Its range extends westward to the states forming the western border of the Mississippi River and north into Canada, in Ontario and Quebec. Close relatives include P. trifolius L. (dwarf ginseng) which also grows in eastern North America and P. ginseng C. A. Meyer (Asian ginseng), native to Asia. P. quinquefolius emerges each year from an underground rhizome in May. Flower buds are evident in mature plants after full expansion, flowering occurs in June, and berries ripen in August and September. The ginseng root is used in traditional Chinese cooking and medicine. In part because the root sometimes resembles a human form, it is believed by users to have therapeutic powers. Since this plant does not have any means of asexual propagation, harvest of an individual kills the plant.