American ginseng: COSEWIC assessment and status report: chapter 10

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Limiting Factors and Threats

The main threats to ginseng are small population size, harvest, and habitat loss and degradation from clearing and logging. Most known ginseng colonies are small in Canada (Figures 3 and 4). Small populations are highly vulnerable to environmental stochasticity, natural catastrophes and to a lesser extent, demographic stochasticity (Menges, 1992). Most small populations revisited in Ontario in 1997, were declining (Nault, et al., 1998). Harvest is a very common practice in Canada, especially in Ontario, where it affected 55% of surveyed sites. Nine populations were apparently lost due to harvest. The conservative life history strategy of ginseng explains its high sensitivity to harvest. Diggers collecting the largest plants found, remove the part of the colony that ensure population maintenance. It severely reduces the colony reproductive potential. Sutter (1982) estimated that a collected population is producing the equivalent of 12-25% of seeds produced in a non-harvested population. According to Nantel et al. (1996), a 5% annual root harvest is sufficient to bring a viable ginseng population toward extirpation.

Figure 3: Sizes of American Ginseng Populations Surveyed from 1996 to 1998 in Ontario

Figure 4: Sizes of American Ginseng Populations Surveyed from 1994 to 1998 in Quebec

Historically, diggers in Ontario seemed to have a responsible approach, harvesting roots late in the season, replanting seeds found on collected plants, and leaving some mature plants to enhance recruitment (White, 1988). The major increase in harvesting rates, however, suggests that attitudes have changed. In North Carolina, diggers harvest everything they find before another digger can come and take the rest (Sutter, 1982). Since the ban on exporting wild ginseng root from Ontario, there is no source of information concerning the amount of wild root harvested every year. It was estimated that an average of 330,000 ginseng roots per year (i.e. 248 pounds of dry roots) were harvested in Ontario between 1983 and 1986 (White 1988). The impact of stopping wild ginseng export in Canada on harvest rates is unknown. Although domestic sale is taking place, there is no estimate of sales volume currently available. Therefore, the impact of domestic sales on wild populations cannot be evaluated. Wild ginseng is widely available in the Asian natural food stores of Toronto (Wilkins, 1998).

Habitat loss and degradation is also a major threat for ginseng. Logging contributed to the loss or decline of 25% of sampled sites in Ontario. In Quebec, habitat loss and degradation seem responsible for the extirpation of seven populations (Table 3). American ginseng usually grows under closed forest canopy. Logging activities open the canopy and strongly modify the ecological parameters of a site (Nault, et al., 1998). After the canopy is opened, light intensity increases, soil moisture declines, daily temperature fluctuations of the forest floor are higher, invasive species are introduced, and competition from tree seedlings, shrubs and herbs increases dramatically. Large individuals that survive such major habitat disturbances, also face intense grazing and seed predation by deer who are attracted by the vigourous forest floor regrowth (pers. observ.). In the eastern Ontario and Quebec portion of ginseng’s range, there was a severe ice storm in January of 1998 that caused major damage to the forest canopy. The canopy loss in many ginseng colonies is comparable to heavy selective logging (pers. observ., 1998) and this storm may have a lasting negative impact on a number of colonies.

Ginseng cultivation is a very lucrative industry in Canada. In 1995, the export market value was estimated at $65 million (Clark and Kort, 1996). Canada is presently the fourth ginseng producer in the world (N. Charest, AgCan, pers. comm., 1998). In Ontario, from 1991 to 1995, cultivated ginseng areas increased 250%, from 1564 to 5500 acres (Clark and Kort, 1996). This increase in production has reduced the price paid for field-cultivated ginseng root. The price for wild ginseng root, however, remains high. As a result, there has been an increased interest in woodland-cultivation of ginseng that may represent a major threat for wild ginseng. The habitat disturbances associated with site preparation (understorey clearing) and maintenance (i.e. uses of fertilizers and fungicides), the introduction of seed-borne pathogens that are common in commercial seeds, and the introduction of foreign genes by planting seeds from unknown sources can have a significant impact on wild populations (Nault, 1998). Woods-grown ginseng plantations presently cover from 1000 to 2000 acres in Ontario (Jan Schooley, OMAFRA, pers. comm., 1998). In Quebec, where this industry started only a few years ago, ginseng plantations already occupy about 100 acres (Isabelle Nadeau, CLDE, pers. comm., 1998). Considering the constant habitat loss and degradation of mature forests due to logging, forest management and development, additional habitat loss and degradation due to ginseng cultivation is critical.

Evaluation and Proposed Status

Ginseng was designated as a threatened species in 1988 on the basis of continuing habitat loss, the small size of most populations, and, most importantly, the continuing overharvest of the plant for medicinal use. Before 1988, much wild ginseng was being harvested in Ontario and exported to Asia, however, shortly after the status report was written, exporting wild ginseng was no longer permitted. Harvesting ginseng for domestic sale was unaffected and the root is still widely available in natural food stores (Wilkins 1998). The continuing reduction and eradication of populations due to harvest suggest that closing the export market for wild ginseng has had little impact on ginseng conservation.

There is 139 records for American ginseng in Canada, 65 in Ontario and 74 in Quebec. Among those, 42 Ontario sites were surveyed from 1996 to 1998; 31 populations are extant and 11 extirpated. In Quebec, among the 59 sites studied in detail from 1994 to 1998, 49 are extant and 10 are extirpated. The status of the species, both in Ontario and Quebec, is very precarious. Extirpation rates in the last five to ten years are high (i.e. Ontario: 27%; Quebec: 17%). The distribution range in Quebec is reduced by more than 100 km at its north-eastern limit. Most populations surveyed in Ontario between 1988 and 1997 have been extirpated or are declining. Only seven viable populations are known in Ontario, and 15 in Quebec, but none of them is secure. In Ontario, harvesting between 1988 and 1997 was confirmed or suspected in 55% of the sites visited (9 were lost) and logging was suspected of causing declines in 25% of the colonies. Clearly, harvest and habitat loss and degradation since the 1988 status report have significantly reduced the ginseng population in Canada. Moreover, the potential threat from the quickly-developing woods-grown ginseng industry could have a major impact on the species survival. If this trend is not quickly reversed, ginseng could disappear from much of its Canadian range. Thus, it is recommended that the status designation of threatened be changed to endangered.

The very precarious situation of ginseng in Canada demands concrete actions to promote its survival. We make the following recommendations :

1. Conduct additional field surveys in Ontario to document populations in under-represented areas.
2. Establish a monitoring program in protected areas.
3. Develop a preventive approach to protect all viable populations.
4. Promote restoration of small populations to avoid further extinctions.
5. Conduct an impact-assessment study of the effects of wood-cultivation on the ginseng habitat.
6. Apply phytosanitary control for commercial seeds.
7. Legislate an outright ban on the domestic sale of wild ginseng root.
8. Re-evaluate the species’ status within three to five years.

Protection

Since the designation of ginseng as a threatened species, few steps have been taken to enhance the species’ chances of survival in Canada. Since ginseng is listed under Appendix II of CITES, the Ontario government was required to monitor the species to ensure that it did not become endangered due to overharvest for international trade. Shortly after the COSEWIC designation of threatened status was made, export permits were no longer issued for Ontario-dug wild ginseng. Surprisingly, U.S. Customs data shows that the United States imported 6000 kg of wild ginseng roots from Canada in 1996 (Robbins, 1998). Two possibilities are suggested to explain the situation : 1) misreporting cultivated ginseng for wild ginseng and 2) Canada exporters using the term “woods-grown” on shipping manifests that is interpreted and reported as wild ginseng by U.S. Customs. Some wild ginseng has been seized during the inspection of materials submitted for export permit to CITES. A single shipment of 16 pounds of dry roots was confiscated in 1997 (Coote, 1998). Lack of resources to verify each parcel submitted to CITES for permit delivery can result in the illegal export of wild ginseng along with cultivated roots. High quality wild roots are suspected of being exported from Canada to Asia in small quantities in personal luggage (Coote, 1998). In the United States, the exportation of wild ginseng increased dramatically from 1990 to 1996, from 67 to 190 metric tons (Robbins, 1998). It is not known how much of this vast quantity is truly wild root and how much is woods-grown.

Several populations of ginseng occur in provincial parks or other “protected areas”. In Ontario, trails near at least two populations in protected areas have been relocated in order that the ginseng remain “out of sight”. One trail relocation occurred after a partial harvest. In the second case, only a minor change was made to the trail; the large population nearby was harvested a few years later. Another large colony in a soon-to-be-developed private woodlot in eastern Ontario was relocated to a protected area in 1991 (by DJW).

In Quebec, a conservation project for ginseng was initiated in 1994 at the Biodome of Montreal, to 1) characterize ginseng populations and their habitat; 2) develop micropropagation techniques for restoration purposes and 3) restore 10 depauperate populations (Nault, et al., 1997). In 1997, a monitoring program was established in 10 key sites through the province and restoration efforts were maintained. Collaboration is also taking place with ginseng producers in the province (via the Centre local de développement de l’érable, Plessisville). They are informed of the species status in the wild, and of the possible impact of wood cultivation on wild colonies. Ginseng should soon be designated a “threatened” species in Quebec, under the Endangered Species Act (bill 108) (Nault, 1997).