Young, John, David Smith, and Tim King. USGS Leetown Science Center, Kearneysville, WV.

(Presented at The Future of Ginseng and Forest Botanicals Symposium, July 12-14, 2017, Morgantown, WV)

Abstract

In an effort to better understand the distribution, population density, and genetic structure of American ginseng (Panax quinquefolius) on mid-Atlantic US National Forests, the USGS, at the request of the USFS, conducted a comprehensive study on four National Forests in 2014-2015.  Field surveys, guided by a randomized field survey design and species distribution modeling, were conducted on the Monongahela (WV), Wayne (OH), Pisgah (NC), and Nantahala (NC) National Forests.  Data collected in field surveys was used in subsequent statistical population density estimates, population simulation under various harvest and stewardship scenarios, and genetic analysis.    We found American ginseng plants generally widely distributed in accordance with predicted habitat, but at low densities in field plots. The highest densities were found on the Nantahala NF, followed by the Pisgah NF, the Monongahela NF, and lowest densities on the Wayne NF.  Through population survival modeling we found that probability of extinction decreases with stewardship behaviors, especially re-planting of seeds, but the probability of extinction was never zero.  Simulated population viability was highly dependent on initial population size, survivorship scenario, harvest timing, and stewardship type.  Results of genetic analysis were highly variable among sample sites, with some sites highly diverse and others consisting largely of selfed progeny.  In general, we found that more genetic diversity is held among populations within Forests (51%) than within populations (36%), and only a small fraction of genetic diversity is held among the four Forests (13%).  These findings suggest that care should be taken to maintain as many individual populations as possible as a large proportion of the existing genetic variation is apparent among populations, and remaining populations, while widely dispersed, currently exist at low densities and are susceptible to harvest pressure.