Many scientists with long-term research programs find a system that fits their interests perfectly and provides an endless series of significant questions to pursue. For me, this opportunity came when I discovered the charismatic medicinal plant, American ginseng (Panax quinquefolius). We have also studied goldenseal (Hydrastis canadensis) and black cohosh (Actaea racemosa, formerly Cimicifuga racemosa), but ginseng has fascinated us for the past decade for several reasons. First, people care about ginseng. Thousands of rural harvesters take to the woods each year to dig roots, then dry and sell them to dealers. Worth about a dollar a root at current prices, this can yield a substantial income supplement in areas of Appalachia where economic opportunities are few. There is a lore associated with the plant...a level of fascination, even reverence, that is unusual for any plant. That reverence follows the harvested root all the way to Asian markets, where the use of wild roots in traditional Chinese medicine as an 'adaptogen' and energy restorative, particularly for the elderly, has a long and storied history. Widespread harvest triggered protection under CITES (the Convention on International Trade in Endangered Species), Appendix II. Harvest seasons were put in place, along with dealer licensing and export monitoring. Precious little was known about the effects of harvest, or whether the regulations were working to enhance sustainability. Ecologists are interested in ginseng as a bellwether, a 'canary in the coalfields', so to speak, an indicator species of larger human-induced changes occurring in the eastern deciduous forest where ginseng grows: land use shifts, global warming, invasive species, deer overpopulation - all factors that affect most understory plants of the rich mixed mesophytic forest. Can a long-lived perennial plant such as ginseng survive and thrive in the face of these changes?
Our first (2002-2006) four-year National Science Foundation-funded project involved an in-depth evaluation of population viability in up to 30 populations of American ginseng spread across the central portion of its range. We were concerned with population viability as it may be affected by human harvesters, as well as by deer, which are increasingly browsing ginseng each year. This has been a productive avenue of research over the past several years. Erin Hackney’s (MS) work, published in Conservation Biology, clearly showed the existence of an Allee effect (lowered reproductive output) in small experimental populations ginseng (Hackney and McGraw 2001). Martha Van der Voort’s (PhD) work (Van der Voort et al. 2003) showed that goldenseal recovers rapidly from harvest via root sprouts, while ginseng recovers much more slowly and appears more vulnerable to harvest over the long-term. Her PhD work provided a detailed examination of the effect harvester behavior on ginseng population growth (Van der Voort and McGraw 2006). Our work has also shown that the distribution of ginseng is more widespread than previously thought, while goldenseal is relatively specialized (McGraw et al. 2003). A study of herbarium specimens showed a century-long decline in ginseng plant size range-wide (McGraw 2001). Suzanne Sanders’ PhD study of goldenseal helped to elucidate reasons for its rarity in nature. Mary Ann Furedi’s PhD work on the deer-ginseng interaction demonstrated clear negative effects and is adding substantively to the call to control deer overpopulation. Emily Mooney's PhD project examined the selective effects of harvest (Mooney and McGraw 2007) as well as the prevelance of inbreeding and outbreeding depression (Mooney and McGraw, in press, American Journal of Botany).
Most exciting was the publication of our population viability analysis in the journal Science (McGraw, and Furedi (2005). This work resulted in coverage by NPR's All Things Considered, National Geographic, Scientific American, USA Today, New York Times, Washington Post, LA Times, and over 100 other news outlets.
Our ginseng research is continuing full steam ahead with our recently funded NSF LTREB (Long-term Research in Environmental Biology) grant (2006-2011). Conservation Fellow and PhD student Sara Souther is studying the effects of global warming on population distribution and viability. MS student Kerry Wixted is studying the effects of invasive species, especially garlic mustard, on ginseng seedlings and adults. Each summer, we train conservation interns to participate in large-scale censusing of ginseng populations, and encourage them to develop independent research projects as well. In 2007, our summer interns were Allison Kenyon, Clare Maloy, and Mark Guido.
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Three prong adult ginseng plant in late August. The most valuable wild harvested plant in West Virginia. Dried ginseng root can bring as much as $500 per pound to rural harvesters. Over $6 million of root is sold every year in West Virginia alone. Increasing rarity of this species has prompted our research on how to regulate harvest in such a way that harvesters may actually improve ginseng’s long-term prospects for survival.
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