Threats to Wild American Ginseng:
Poor Harvest Practices
Throughout history, dramatic increases in harvest rates ('boom times') have been followed by 'busts', in which harvest falls quickly because the resource has been depleted. Even since being listed on CITES in 1975, which has afforded some protection, harvest has been shown to have dramatic negative impacts, especially when done poorly.
Scientific research has revealed the precise nature of these poor harvest practices, identifying not only why populations decline, but what alternative behaviors could improve the equation for wild populations. This scientific documentation has led to significant policy changes, but it is even more important that harvesters learn how to leave behind an abundant resource for their children's' and grandchildren's' generations.
Aftermath of an early, out of season harvest, June 19 2017.
Taken in the field during a McGraw Labs field study.
Credit: J.B. McGraw
The 'Down Side' of Wild Harvest
Harvest of ginseng has a long history in eastern North America, and there is no doubt that unregulated harvest can harm wild populations. Here is what scientific studies have shown about the direct and indirect effects of harvest:
• Unethical harvest is common and occurs in three ways: (7)
(1) Harvest occurs frequently in places where it is not legal.
National parks, nature preserves, state parks, and state forests appear to be particularly vulnerable, yet harvest is illegal in most such settings.(7) Harvesters must resist the urge to dig plants where it is illegal. Not only is this behavior criminal, and subject to prosecution, it prevents our nature preserves and parks from acting as intended… as society’s “Noah’s Arks.” Like marine reserves in the ocean (where fishing is prohibited), parks and preserves on land act as genetic reservoirs that can be sources for later re-colonization elsewhere.
(2) Harvest often occurs out of season.
This makes it impossible to harvest sustainably because seeds are not yet ripe, and unripe seeds do not germinate. (6,7)
(3) Plants are harvested that are too small.
Most state regulations stipulate that plants must be 3-pronged prior to harvesting, yet many are taken before that size threshold is reached. (7) This means that those plants have likely not replaced themselves before being removed from the population.
• Even ‘compliant’ harvest – in which diggers follow the letter of the law – is not sustainable in the long-term.
However, harvesters acting in a stewardship manner can not only sustain populations, but grow them. (3)
• Harvest that reduces population sizes has indirect negative effects, including:
(1) Reduced ‘mating success’ (lower seed production)(8)
(2) Lower genetic diversity (9)
(3) Lower fitness due to inbreeding (10)
(4) Selection against large sized plants (11)
(5)Decreased root sizes, as evidenced by shrinkage over the past two centuries (12)
• The effects of harvest may worsen when other factors are considered.
-Harvest effects are more severe in a warmer climate (13)
-Effects of climate change on viability may be worse when harvest is also present (13)
Reducing Effects of Harvest - Beyond 'Compliance'
Harvesters can reduce negative effects of harvest by harvesting only (1) during the harvest season, on land where permission has been explicitly granted, and (3) complying with size requirements. In other words, comply with regulations designed to reduce impacts of harvest.
• Harvesters can further reduce their impacts by on-site planting of the seeds from harvested plants in an optimal manner.
A study showed that optimal planting depth is about 1 inch deep. (6) It has been speculated (though not shown with experiments) that each seed should be planted separately near the parent plant, because if the parent succeeded in that environment, the offspring would likely succeed too, but not too near (to avoid disease transmission to the young seedling) – perhaps 2 – 4 ft away, with some consideration given to reducing visibility/access to both deer and harvesters.
• Harvesters can reduce impacts of removing large plants by taking only plants with viable seeds. (3)
This is one component of a stewardship approach to harvesting, whereby diggers sacrifice some current profit – leaving behind non-reproductive individuals – in order to ensure a profit in the future in the form of a sustained or growing population.
• Good harvesting practices are outlined by the American Herbal Products Association, with links to downloadable brochures specific to each state that allows harvesting.
It is relatively simple to practice good harvest behavior, which doesn’t negatively impact ginseng population growth.
• Good Stewardship is crucial for the future of wild American ginseng.
(1) Charron and Gagnon 1991. The demographic of northern populations of Panax quinquefolius (American ginseng)
(2) Nantel et al. 1996. Population viability analysis of American ginseng and wild leek harvested in stochastic environments.
(3) Van der Voort and McGraw 2006. Effects of harvester behavior on population growth rate affects sustainability of ginseng trade.
(4) Farrington et al. 2008.
(5) McGraw et al. 2013. Ecology and conservation of ginseng (Panax quinquefolius) in a changing world.
(6) McGraw et al. 2005 Berry ripening and harvest season in wild American ginseng.
(7) McGraw, Souther, and Lubbers 2010. Rates of harvest and compliance with regulations in natural populations of American ginseng (Panax quinquefolius L.).
(8) Hackney and McGraw 2001. Experimental demonstration of an Allee effect in American ginseng.
(9) Cruse-Sanders and Hamrick 2004. Consequences of harvesting for genetic diversity in American ginseng (Panax quinquefolius L.): a simulation study.
(10) Mooney, E. H. and J. B. McGraw. 2007. Effects of self-pollination and outcrossing with cultivated plants in small natural populations of American ginseng, Panax quinquefolius (Araliaceae).
(11) Mooney and McGraw 2009. Relationship between age, size and reproduction in populations of American ginseng, Panax quinquefolius (Araliaceae), across a range of harvest pressures.
(12 ) McGraw 2001. Evidence for decline in stature of American ginseng plants from herbarium specimens.
(13) Souther and McGraw in press (Ecological Applications)
How to be a good steward of American ginseng:
(2) If harvesting wild American ginseng, use ethical harvest guidelines and reduce the impact of harvest using the principles of good stewardship.
(3) Learn about and support programs, groups and businesses that practice sustainable or ethical sourcing, for American ginseng and other plants like it.
Collecting American ginseng berries to plant. Credit: batcavebotanicals, 2016