Issue:
119
Page: 40-55
Protecting Goldenseal:
How Status Assessments Inform Conservation
by Leah E. Oliver, Danna J. Leaman, PhD
HerbalGram.
2018; American Botanical Council
Summary
A recently
published global assessment of the conservation status of goldenseal (Hydrastis
canadensis, Ranunculaceae) has found that the species is Vulnerable to
Extinction (i.e., it faces a higher risk of extinction in the wild throughout
its distribution in the United States and Canada than many other species).
However, the extinction risk is not yet at the level of Endangered (very high
risk of extinction) or Critically Endangered (extremely high risk of
extinction). This article explains two complementary conservation ranking
methods — the International Union for the Conservation of Nature (IUCN) Red List
and NatureServe — and the criteria applied to assess the conservation status of
goldenseal. These assessments consider all primary threats to goldenseal
conservation, including the impact of habitat loss and other factors, such as
domestic and international trade, and propose measures to support in situ and
ex situ conservation of this species.
Introduction
In 2017, the IUCN
published the first comprehensive global Red List assessment of goldenseal,
which concluded that the species is globally Vulnerable, a category that
indicates a high risk of extinction in the wild.1,2 To determine
risks of extinction, the IUCN Red List of Threatened Species uses a
scientifically rigorous approach that is applicable to all species. It has
become a world standard, providing information and analyses on the status,
trends, and threats to species in order to inform and catalyze action for
biodiversity conservation.3 The assessment was authored by
NatureServe, a nonprofit network of scientists that provides access to and analysis
of current data on biodiversity. The 2017 IUCN assessment followed and built on
NatureServe’s 2012 global ranking update, which classified goldenseal as G3G4 —
a range rank that spans G3 (Vulnerable; a moderate risk of extinction) and G4
(Apparently Secure; some cause for long-term concern).4
Over the last two
decades, the North American herb industry has made substantial efforts to
recognize threats to goldenseal populations, raise industry and consumer
awareness about the need for goldenseal conservation, and invest in
commercial-scale cultivation of the species.5-7 However,
wild-collectors, cultivators, conservationists, and other members of the herbal
community have questioned the rationale for the IUCN and NatureServe
conservation assessments and the information on which they are based. This
article aims to provide transparency about these assessments by explaining the
history, rationale, and challenges behind them, and to explore what the
conservation status of goldenseal signifies for the current and future
sustainability of this important North American herb.
What
is Goldenseal?
Goldenseal is a
long-lived, perennial plant that is native only to North America, where it
grows in densely shaded, deciduous forests. Naturally growing populations are
known to occur in 26 states in the eastern United States, ranging from southern
Vermont, west to Minnesota, and south to Georgia, Alabama, and Arkansas. In
Canada, naturally growing populations are known to occur only in southwestern
Ontario.1,8 The core part of its range includes the Ohio River
Valley states of Indiana, Kentucky, Ohio, and West Virginia.9,10
There are no state-level or range-wide population estimates for goldenseal,
which is typical of most wild-harvested plant species.11
Goldenseal appeared
in early records of medicinal uses of North American plants.12
Native Americans and Canadian First Nations have used various parts of this
plant — especially the rhizomes and roots — in traditional remedies for cancer,
eye ailments, inflammation, digestive problems, pneumonia, and heart problems.13
European colonists adopted and popularized some of these applications. In the
1900s, increased demand for goldenseal was caused in part by its unfounded
reputation for masking illicit or performance-enhancing drugs in urine tests.14-16
This myth apparently grew from a murder mystery published in 1900 in which
goldenseal bitters were erroneously identified as strychnine, which inspired an
otherwise unfounded association of goldenseal with chemical testing errors in
American folklore.15,17 Demand for goldenseal has increased over
time, as applications have expanded beyond traditional and local uses and
interest has been renewed in herbal medicines in North America and
internationally.4,17 More recently, the identification of the
alkaloids berberine, hydrastine, and canadine in goldenseal provided a
scientific basis for its use in certain conditions.18
Goldenseal
currently is used mainly as a component of traditional herbal medicine
formulations marketed as licensed Natural Health Products (NHPs) in Canada19
and as dietary supplements in the United States. The export market is
relatively small and limited primarily to countries with Western herbal
medicine traditions, such as Australia and the United Kingdom. Goldenseal also
is exported to Europe in small quantities for use in two traditional German
systems of medicine: anthroposophical medicine and homeopathic medicine (J.
Brinckmann email to C. Yearsley, March 17, 2018). The World Health Organization
includes goldenseal rhizome (Rhizoma Hydrastis) among materials that have
global importance in alternative medicine, with its main use described in
pharmacopeias and “well established documents” as a treatment for digestive
complaints, in addition to a variety of other traditional uses.20
Conservation
Concerns
Wild goldenseal
subpopulations have declined dramatically due to habitat loss and degradation
through forest conversion for agricultural use, urban expansion, road
intrusion, and recreational use. Population decline also has been caused by
commercial collection that began in the mid-1800s.17,21 Concerns
about the conservation of goldenseal have existed since at least 1884, when
American pharmacist John Uri Lloyd (author of the aforementioned murder mystery
novel) and his brother, mycologist Curtis Gates Lloyd, observed that goldenseal
rhizome harvesting and habitat loss were causing significant declines in
goldenseal subpopulations.22 Botanists’ observations from this
period onward provide anecdotal and observational evidence of the continued
decline and loss of goldenseal subpopulations from habitat loss and degradation
and increasing demand for wild-collected rhizomes.23-39 Approximately
80% of the original forests in New England have been lost to land conversion,
which reached its peak during the 1800s.40 In the Canadian portion
of goldenseal’s range, less than 5% of its forest habitat remains from
pre-settlement times.8
Although goldenseal
was cultivated on a small scale for more than a century throughout its native
range, most of its domestic and international trade until the early 2000s came
from wild-harvested rhizomes and roots.10 There have been efforts to
account for harvest and trade volumes in national and international trade by
using records of phytosanitary certificates issued by the US Department of
Agriculture (USDA) and by tracking trends in supply and demand (e.g., using
wholesale prices published in US herb catalogs).39 However, in the
absence of any official monitoring and reporting requirements, it was not
possible to accurately quantify the volumes of roots harvested, traded in
domestic markets, or exported from North America.5,41
Subpopulations in
Canada were first assessed as Threatened in 1991 by the Committee on the Status
of Endangered Wildlife in Canada (COSEWIC).42,43 By the mid-1990s,
goldenseal in the United States was considered Critically Imperiled, Imperiled,
or Uncommon in 17 of the 26 states in which it occurs.39,44
According to Bannerman (1997), wild harvest was prohibited in a number of
states due to concerns about population decline.5
Herbalists also
are concerned. United Plant Savers (UpS), a nonprofit organization dedicated to
the conservation of native American medicinal plants, included goldenseal in
its original list of “Species At-Risk” that identified plants in decline due to
expanding popularity and shrinking habitat and range. This list was created in
1997 by “concerned herbalists and conservation-minded plant enthusiasts” to
encourage practical and educational programs and to promote organic cultivation
of “At-Risk” herbs.6,45
CITES
Listing
In 1997, the North
American office of TRAFFIC: The Wildlife Trade Monitoring Network formally
petitioned the US Fish and Wildlife Service (USFWS) to propose goldenseal for
inclusion in Appendix II of the Convention on International Trade in Endangered
Species of Wild Fauna and Flora (CITES).17 The proposal was adopted
at the 10th meeting of the Conference of the Parties to CITES in June 1997.39
While conservation experts and officials in importing countries were concerned
that supplies of goldenseal would fall and prices would rise if goldenseal were
included in Appendix II, the conference decided to adopt the proposal.
Goldenseal was
listed in Appendix II on September 18, 1997, with an annotation to focus on
trade in “whole and sliced roots and parts of roots, excluding manufactured
parts or derivatives such as powders, pills, extracts, tonics, teas and confectionary.”
This listing means that all international exports and re-exports of goldenseal
roots and rhizomes, whether wild, forest-grown, or cultivated, require permits
issued by the CITES Scientific Authority to enable monitoring and control of
materials and volumes in international trade. A CITES export permit signifies
that the transaction is legal and does not threaten the species’ survival in
the wild.46 Obtaining a permit to export goldenseal also requires
proof that the roots, rhizomes, or seeds came from legally acquired parental
material and from plants that were at least four years old.47
Increased export
of powdered goldenseal roots and rhizomes from the US after 1997 made it
difficult to monitor international trade48,49 and led the USFWS to
amend the annotation for goldenseal in 2007 to include “underground parts
(i.e., roots, rhizomes): whole, parts and powdered,”49
(emphasis added) so that all of the major goldenseal products in international
trade could be monitored.
Inclusion of
goldenseal in Appendix II stimulated industry investment in research and
education campaigns supporting commercial cultivation of the species.5
For example, propagators and growers worked for more than a decade to improve
seed stratification requirements of goldenseal so that the germination rate
would support sexual propagation (E. Fletcher email to C. Yearsley, March 21,
2018). The herbal industry also implemented measures to track wild and
cultivated production.6,7 Although
nearly all material in trade continued to come from wild collection until the
early 2000s, there has been a shift in the international market to cultivated
sources in recent years.50-52 The CITES Trade Database (2000-2016)
indicates that the majority of material in international trade is now from artificially
propagated plants. Industry surveys of raw herbal materials producers in the
United States undertaken by the American Herbal Products Association (AHPA), a
trade association for the US herb industry, documented an increase in
cultivated goldenseal roots and rhizomes (compared to wild-collected materials)
from a low of 2% cultivated in 1998 to a high of 41% cultivated between 2000
and 2010.51,52
Although CITES and industry trade data indicate that cultivated
goldenseal makes up an increasing portion of international trade, the most
recent publicly available AHPA survey data from 2010 suggest that the majority
of goldenseal raw material in US domestic trade was sourced from wild
collection. For example, in 2010, 59,197 pounds of goldenseal root and rhizome
and 10,791 pounds of leaf were reported from wild sources, while cultivated
sources accounted for 17,931 pounds of root and rhizome and 782 pounds of leaf.51,53
History, Rationale, and Challenges behind the Recent
NatureServe and IUCN Conservation Status Assessments
The transition of international trade of goldenseal from wild-harvested
to cultivated sources has had an impact on goldenseal conservation. In 2012,
the US CITES Scientific Authority, part of the USFWS, initiated a status review
of the species. USFWS engaged NatureServe to carry out the review, with a focus
on filling gaps in information about goldenseal’s abundance, population trends,
life history, core range states, and current threats, particularly the impacts
of ongoing wild harvest. This new information was used to update NatureServe’s
state, national, and global rankings for goldenseal and to complete a global
(United States and Canada) IUCN Red List assessment of this species.
The CITES Scientific Authorities in the United States and Canada rely
on these and other data sources to determine whether international trade is
detrimental to the survival of the listed species. This determination is
referred to as a non-detriment finding (NDF). Although CITES permits and
monitoring focus on material in international trade, for the purposes of making
an NDF, the Scientific Authority “should consider the volume of legal and
illegal trade (known, inferred, projected, estimated) relative to the
vulnerability of the species (intrinsic and extrinsic factors that increase the
risk of extinction of the species),” and, “in considering whether an export may
be detrimental, the sustainability of the overall harvest will usually be a
necessary consideration.”54
Methods and Processes of the Conservation Assessments
Information from scientific literature and databases was collated to
update the population status and threat information already contained in
NatureServe’s central databases and in IUCN’s Species Information Service
(SIS), the database used to compile and manage Red List assessments.
NatureServe carried out formal status assessments based on both NatureServe’s
global ranks55 and IUCN’s Red List categories and criteria.2
Each assessment entailed compiling information relevant to understanding the
risk of extinction for a species: geographic distribution; population size;
number, size, and distribution of subpopulations; population and habitat
trends; type and scale of threats; and existing conservation actions.
Although published literature contains a wealth of useful data about
conservation status factors, active field researchers have the most current
information about the status of wild populations. In 2012, the NatureServe team
contacted botanists at state and federal agencies, natural heritage programs,
and universities, among other experts, to gather information on factors
contributing to goldenseal’s conservation status. NatureServe engaged these
botanists by distributing a survey that included questions about goldenseal’s
distribution on state, federal, and private lands, and protection and
regulation on those lands. A section of the survey focused on information about
population size, viability, and evidence of wild collection. Additionally,
botanists were asked for information about cultivation and wild collection in
each state.
The synthesized data from the scientific literature and expert surveys
provided higher quality and more current rank factor values, which were entered
into NatureServe’s global rank calculator and IUCN’s Red List assessment. Draft
assessments using both the NatureServe rank calculator and IUCN’s SIS were
completed and peer reviewed.
Results of the Assessments
NatureServe previously assessed goldenseal’s global population as
Apparently Secure (G4), indicating that the species is uncommon but not rare,
and that there is some cause for concern due to decline over the long term.1,4
The updated global conservation status of goldenseal using NatureServe’s rank
calculator and ranking guidance is Vulnerable/Apparently Secure (G3G4), which
suggests that there is uncertainty about which of these two ranks (G3 or G4)
best reflects the available information about the species.1,4,55 The
G3 rank indicates that the species’ status may have declined to Vulnerable
(i.e., at moderate risk of extinction due to a restricted range, relatively few
subpopulations or occurrences, or recent and widespread declines or other
threats).55,56 Due to uncertainty about ongoing loss of habitat,
population estimates across the species’ range, and actual levels of wild
collection for the domestic market, G3G4 is believed to convey the most
accurate extinction risk for goldenseal. Based on the available biological and
trade information, including the NatureServe assessment, goldenseal remains in
Appendix II of CITES so that international trade does not reduce the wild
population to a level that would threaten its survival.
The first IUCN Red List global assessment of goldenseal from 2017
determined that the species is Vulnerable.1 This category indicates
that it faces a higher risk of extinction in the wild throughout its
distribution than many other species, but that the extinction risk is not yet
at the level of Endangered or Critically Endangered.
The 2017 IUCN assessment is based on indicators that goldenseal’s
population has declined by at least 30% over the past three generations of the
plant and the assumption that this trend will continue in the absence of more
effective conservation measures. The indicators of population reduction
include: inferred population decline based on firsthand observations in some
subpopulations10,11,63; suspected population decline based on
observed and estimated declines in habitat availability and quality8,21,23;
and suspected population decline based on observed harvest impacts and
suspected levels of exploitation.23 Suspected levels of exploitation
also were based on increasing numbers of requests for wild-harvest permits for
goldenseal, as reported by the Indiana Natural Heritage Program. Adequate
evidence was available to determine that, in the recent past, the area occupied
by all known subpopulations has declined within goldenseal’s native range,
habitat quality has declined, and exploitation of wild subpopulations has
reduced the number of individuals. These are continuing threats.
Assessment Challenges Related to Population Size and Trends
Knowledge of
population biology and trends for goldenseal is more extensive than for many
native species of medicinal herbs, yet estimating the total number of
individuals and the rate of population decline for goldenseal is challenging
because of its widely scattered distribution, relatively long generation length
for an herbaceous plant, clonal habit of reproduction, and the absence of
high-quality population monitoring and genetic diversity data.
Scattered
Distribution
Anecdotal
information from historical documents indicates that goldenseal subpopulations
have declined significantly throughout its range since the early 1800s, but
little quantitative trend data are available for the last 30 years
(approximately three generations).64 Botanical accounts of
goldenseal since the mid-1800s describe dramatic reduction of once-abundant
subpopulations to isolated, scattered patches in parts of its range, and
attribute these declines to habitat destruction, collection for medicinal uses,
and increasing pressure on managed and previously unharvested subpopulations.21,23,25,65
Declines in goldenseal subpopulations have been qualitatively documented in New
York, West Virginia, and Indiana (P. Harmon personal communication to L.
Oliver, November 28, 2012; C. Floyd email to L. Oliver, November 30, 2012).40,63
Fewer subpopulations, patches per subpopulation, and ramets (genetically
identical individuals of clonal species) per patch provide additional evidence
of subpopulation decline.63
Generation Length
The most significant challenge in determining the IUCN Red List assessment ranking of Vulnerable was providing evidence that goldenseal population decline has been and will continue to be at least 30% over three generations. According to the IUCN Red List Guidelines, “generation length should be averaged over asexually and sexually reproducing individuals in the population, weighted according to their relative frequency” in the population.64 Because these parameters are unknown for goldenseal (as indeed they are unknown for most plant species), it is accepted practice to estimate generation length as the age at first flowering and fruiting, believed to be seven to nine years for goldenseal.66 (An expert reviewer of this article noted that there are instances of goldenseal’s life cycle being three to four years in cultivation settings.) The IUCN assessment, however, eventually settled on an estimated generation length of 10 years.
Clonal
Reproduction
Like many plant
species, goldenseal reproduces both sexually and clonally, but this
mixed-mating system makes it difficult to visually distinguish genetically
distinct individuals from clonally identical individuals (ramets) in a
population. Sanders (2004) described goldenseal subpopulations as forming
“dense patches of a few to greater than 1,000 ramets with patches frequently
sparsely distributed across the landscape, such that many patches are isolated
from others by great distances.”67
Plant species that
reproduce clonally create a baffling situation for field biologists attempting
to count or estimate numbers of reproductive individuals in a subpopulation or
the total population. The count of ramets (individual stems in a clone) and
estimates of subpopulation sizes overestimate the number of genetically
distinct individuals and genetic diversity in the population because the ramets
of each clone are genetically identical. Goldenseal ramets have a single stem,
so it is not possible to visually differentiate genetically distinct
individuals.
The current IUCN
Red List guidance recommends that assessors define an individual as the
smallest entity capable of independent survival and reproduction (sexual or
asexual),64 but this guidance does not adequately account for
concerns about limited genetic diversity within and between such populations
that cannot be equated to species that reproduce only sexually (e.g., mammals).
Genetic
Diversity
Several recent
studies have begun to fill a long-standing gap in information about the genetic
diversity of goldenseal. Torgerson (2012) reported low genetic variation across
subpopulations examined in North Carolina.68 In a study that
compared the genetic variation between cultivated and natural populations of
goldenseal in Ohio, Pennsylvania, West Virginia, and North Carolina, genetic
diversity in both settings was found to be low.69 Six cultivated and
11 wild subpopulations shared a high degree of genetic similarity, which is not
surprising, the authors noted, given that the original plants in cultivation
were propagated from wild genetic material.
For most crop
species, plants in cultivation typically have far less genetic diversity than
those in the wild, but this may not be the case for goldenseal. Preliminary
evidence, based on small sample sizes, suggests that goldenseal’s genetic
diversity is low both in the wild and in cultivation.69,70 Wild
subpopulations for most crops are genetic reservoirs that can be accessed to
breed disease resistance or environmental tolerance (e.g., drought resistance)
into cultivated stock. Overall, low genetic diversity in wild populations means
there is less adaptive capacity for environmental stressors, disease, and other
pathogens for both wild and cultivated plants.
High genetic
diversity that is spread across subpopulations implies frequent gene flow from
pollination events among the subpopulations. In contrast, if genetic diversity
is higher within a subpopulation than among them, this suggests that the
subpopulations are genetically isolated from one another, with little
pollination occurring among them. Goldenseal follows the latter scenario. Inoue
et al. (2013) found the highest levels of genetic variation within
subpopulations, and low genetic similarity across subpopulations.69
These results support the hypothesis that goldenseal subpopulations are
isolated from one another, and that pollen exchange among subpopulations occurs
with limited frequency.67
Habitat
Loss, Population Extirpations, and Decline in Habitat Quality
Recognizing that
complete information about population size and trends is lacking for many
species, the IUCN Red List criteria are designed to support the use of other
types of information, such as inference of long-term and short-term population
reductions from observed declines in the area occupied by species
subpopulations and in the number of subpopulations or occurrences.64
Observations of substantial long-term decline of goldenseal’s forest habitat
since the early 1800s contributed to the conservation concerns that led to the
listing of goldenseal in CITES Appendix II. While the pace of land conversion
has slowed since then, habitat loss remains a threat to goldenseal throughout
its range. These ongoing threats have been corroborated by personal
communications with more than a dozen natural heritage botanists from 12 US
states with goldenseal populations.8
Another source of
information used in the conservation status assessments was data on population
extirpations (local extinctions) in the heart of goldenseal’s range. In Ohio, a
state in the core of the species’ range, a study by Mulligan and Gorchov (2004)
found that nine of 71 historical occurrences were extirpated.21 Of
the 42 goldenseal sites documented in Ohio from 1977-1998, 14 sites were
extirpated as of 2002. If the rate of extirpation is assumed to be constant,
approximately 1.6% of goldenseal subpopulations are extirpated each year in
Ohio, amounting to an approximately 30% decline in the number of subpopulations
over a 20-year period (D. Gorchov email to L. Oliver, November 1, 2012).21
The observed rate of extirpation of goldenseal occurrences in Ohio is likely to
be about the same or higher in states on the periphery of goldenseal’s
distribution, where subpopulations are smaller and more scattered. This rate of
decline meets the threshold criterion for the IUCN Red List category
Vulnerable, inferring from the estimated rate of subpopulation decline an
overall population reduction of at least 30% over the past three generations
(21-28 years).1,2
Mulligan and
Gorchov determined that only 13% of documented extirpations in Ohio were due to
deforestation, which suggests that threats other than land conversion caused
most of the observed extirpations of goldenseal subpopulations.21
Decline in the quality of goldenseal habitat also results from ongoing impacts
of agricultural expansion, urbanization, recreational use of forests, and road
building and maintenance. Other threats leading to habitat degradation include
loss or disturbance by flooding and/or fire, invasive species, trampling,8,71
and browsing by deer.21
Population
Impacts of Wild Collection
Continuing decline
in the global goldenseal population resulting from habitat threats is
exacerbated by wild collection. Mulligan and Gorchov attributed 10% of the
observed rate of decline in goldenseal subpopulations in Ohio to wild
harvesting.21 They also noted that goldenseal subpopulations in Ohio
are smaller, with fewer flowering plants than goldenseal subpopulations in
Ontario, and suggested that the difference may be attributed to wild collection
being permitted in Ohio and prohibited in Ontario. Christensen and Gorchov (2010)
observed that goldenseal harvesters usually collect rhizomes of the largest
individuals. They explain that this practice, over time, results in smaller
subpopulation sizes and smaller proportions of large, reproductive individuals
by adversely affecting population regeneration through both sexual and asexual
reproduction.10
The volume of wild goldenseal rhizomes and roots exported from the
United States and Canada has been monitored and documented based on CITES
permit data since the end of 1997 in compliance with these countries’
obligations as signatories of CITES.52 These trade data indicate
that wild-harvested goldenseal material has substantially declined relative to
the increasing supply of cultivated material in the international market. As
mentioned previously, herbal industry surveys of relatively small numbers of
primary raw material producers of goldenseal documented an average of 40 tons
of goldenseal root (wild and cultivated) in trade per year in the United States
between 2004 and 2010.51 These surveys also indicated that 75% of
the tonnage of wild goldenseal in US trade from 1999-2010 was wild harvested.
In the absence of more comprehensive and systematic monitoring and
documentation of wild goldenseal baseline population data and volumes in
domestic trade in the United States, the harvest pressure on the wild
population is not quantifiable.
Some illegal wild harvest of goldenseal subpopulations in Canada occurs.71,72
Wild harvest in some parts of the species’ range in the United States is likely
increasing, especially where wild collection remains an important source of
income and unemployment is high.47 In Indiana, for example,
collection pressure has increased dramatically over the last decade (C. Floyd
email to L. Oliver, November 30, 2012).
Current Outlook and Moving Forward
Conservation concerns that led to goldenseal’s inclusion in CITES
Appendix II in 1997 stimulated research on what is needed for goldenseal to
survive in its remaining natural habitat, much of which informed the updated
NatureServe ranking in 20124 and the first global IUCN Red List
assessment in 2017.1 Without the inclusion of goldenseal in CITES
Appendix II and the subsequent shift in the international commercial goldenseal
market from wild-harvested to cultivated supply, it is probable that this
species would now be more seriously threatened with extinction than it appears
to be at present. CITES permit requirements reduce unsustainable wild harvest
and promote protection of goldenseal and its habitat, and removing these
requirements could eliminate the most effective mechanism currently available
to avoid greater extinction risk. Failure of resource managers and the herbal
industry to take stronger actions to reduce the main threats — population
decline from habitat loss and unsustainable levels of wild harvest — risks the
viability of the species, commerce, and the livelihoods of those that rely on
this resource.
In Situ Conservation
Goldenseal is not listed under the US Endangered Species Act and
therefore is not protected under US federal law. Protection within states
varies considerably, both in terms of how states designate and protect
imperiled plants in general, and goldenseal’s protection across the states in
which it occurs. The USDA PLANTS database tracks state-level legal protection.
In 2018, goldenseal was considered Endangered, Threatened, Vulnerable, or of
Special Concern in 12 out of the 26 states in which it occurs.73
Another measure of species imperilment at the state level is NatureServe’s
state conservation rankings. According to NatureServe’s state ranks, goldenseal
is Critically Imperiled or Imperiled in 12 states on the periphery of its
range; Vulnerable in seven states, some of which are in the core of its range;
and Apparently Secure or Secure in the remaining seven core-range states where
it is native.4 There is a need to more adequately assess whether
state regulations are sufficient to protect wild populations of goldenseal.
Targeted field studies are warranted to ensure that the population integrity
(area occupied and conditions) meets the lower threshold of each state’s
NatureServe ranking. Field inventory is an ideal method to inform these
thresholds; however, they are typically reserved for the “rarest of the rare”
species due to limitations in resources. Given goldenseal’s economic and
medicinal value and the ongoing threats that it faces, states should consider
prioritizing goldenseal for field inventory to avoid further decline in its
habitat and population.
Many subpopulations throughout goldenseal’s range occur on land managed
by national, state, local, or private organizations, including some
subpopulations within Nature Conservancy preserves. Plant collecting on federal
land is either forbidden (e.g., on National Park Service land) or requires
permits (e.g., on Forest Service land). Harvest regulations differ from state
to state. Some states, such as Pennsylvania, require permits for collection on
State Forest land or the written permission of landowners for collection on
privately owned land.74 But harvest and interstate commerce of
goldenseal root and rhizome as a botanical commodity remain largely unregulated
and unmonitored. The Indiana Department of Natural Resources reported an
increased demand for this species and concern that the volume of material
exported from Indiana will lead to decline of the species in the state. Plants
on public and protected lands need protection from illegal collecting71
and application of good stewardship practices (e.g., late-season harvest to
allow seed dispersal) where collecting is permitted.74 Existing
regulations protecting goldenseal and other non-timber forest products on
public and protected lands need to be better integrated into forest and other
resource management plans and practices.75
Goldenseal was assessed as threatened by COSEWIC in 199142
and reassessed as threatened in 2000.43 Goldenseal has federal
protection in Canada under the Species at Risk Act and in the province of
Ontario under Ontario’s Endangered Species Act. Monitoring undertaken in
Ontario in 1998 documented the loss of three previously known subpopulations
but an overall stable, or possibly increasing, colony size.76 A
recovery strategy for goldenseal in Ontario was published in 2016 in compliance
with federal and provincial requirements for species at risk, and it
recommended measures “to maintain existing populations at sustainable levels.”71
International trade of wild-collected goldenseal from Canada has not
been permitted since the species was listed in CITES Appendix II because all
wild harvest is considered by the Canadian CITES Scientific Authority (Canadian
Wildlife Service, Environment and Climate Change Canada) to be detrimental to
the survival of the Canadian subpopulations. All herbal medicinal products
containing goldenseal, whatever their origin, must contain only cultivated
material to receive marketing authorization and a product license for
commercial sale in Canada.19
The NatureServe and IUCN conservation status assessments of goldenseal
highlight “habitat depletion as one of the biggest negative impacts on
goldenseal” and the need for legal protection “that prevents the destruction of
habitat where goldenseal grows natively,” according to Ed Fletcher, the
director of quality and sustainability at Herbal Ingenuity, a raw material
supplier based in Wilkesboro, North Carolina (E. Fletcher email to C. Yearsley,
March 17, 2018). Josef Brinckmann, the medicinal plants and botanical supply
chain research fellow at Traditional Medicinals, a wellness teas company based
in Sebastopol, California, explained that habitat loss through deforestation
and land use change threatens “all wild forest plants, including goldenseal.
Our last remaining biodiverse forests need to be conserved and expanded through
reforestation,” he wrote (J. Brinckmann email to C. Yearsley, March 21, 2018).
One such example of wild forest conservation is the 379-acre UpS Sanctuary in
Rutland, Ohio, and other sanctuaries maintained by UpS members.77
Potential for Sustainable Wild Collection
In his monograph on goldenseal published in 2011, herbal expert,
photographer, and author Steven Foster wrote, “One of the big questions facing
the future of goldenseal is whether there is enough supply, especially of
wild-harvested root, to meet the demand.”17 Although loss of forest
habitat has been the primary cause of decline of goldenseal over time, the
sustainability of wild harvest is also a concern. A conservation assessment of
goldenseal prepared by the USDA Forest Service in 200378 recommended
that “to successfully maintain and increase the existing Hydrastis
canadensis populations [on Forest Service lands], harvesting should not be
allowed.”17
In 1997, ecologist and educator Joy Bannerman, in an HerbalGram
article from issue 41, wrote:
There is presently no scientifically valid guideline for
“ethical and sustainable harvesting” [of goldenseal] in the wild since
significant aspects of population and reproductive biology are unknown.
Statements by herbal companies that such material has been “ethically
wildcrafted” or the assurance that such is the case by having collectors or
sellers sign a document to this effect is scientifically indefensible at this
time.5
Since then, however, there has been more research on what goldenseal
needs to survive and population dynamics of this species (low instances of seed
production, high energetic cost of flowering, low genetic diversity, and small,
isolated populations), and work on protocols for sustainable wild harvest of
medicinal plants in general also has advanced.79-82 The herbal
industry is in a better position now to demonstrate that goldenseal can be wild
harvested sustainably.
The USDA requires implementation of a detailed, audited,
and monitored sustainable resource management plan for wild-collected herbs in
the United States that are certified as organic under the National Organic
Program in compliance with the Organic Wild-crop Harvesting Practice Standard.83
In addition, AHPA has developed voluntary guidelines for Good Agricultural and
Collection Practices (GACPs) that focus on desired quality and long-term
sustainability for botanicals in general.81 AHPA’s recommendations
include:
- Obtain necessary permits,
licenses, and permissions for access to public or private property.
- Choose collection
sites that contain “healthy stands of plants growing in their normal range and
in large enough quantities for collection to be sustainable.”
- Use “collection
practices that are appropriate to each species and collection area and that
minimize damage to the local habitat.”
- Avoid harvest of
“species listed as endangered or that are not allowed to be harvested under
state regulations due to concerns about over-harvest.”
- Collect mature
plants “only from stands … that are abundant and healthy, with multiple plants
of differing ages (seedling, juvenile, and mature).”
- Use collection
practices for specific plant parts “that maintain population stability.”
- Use “propagation and
regeneration techniques during harvest.”
- Use “habitat
stewardship techniques during harvest.”
- Maintain records
“that document information and collection practices that ensure the
sustainability of the harvest.”
- Ensure all
harvested plants are identified correctly.
- Develop a “comprehensive written wild collection plan.”
While general guidance on good harvesting practices is a step forward,
companies are not required to develop standard operating procedures to
implement AHPA’s GACP guidelines. There is a significant gap in assurance and
rigor between recommendations and audited standards. Species that are at high
risk of unsustainable harvest require a management system that includes careful
evaluation of sustainable yield, monitoring of harvest impacts, verification of
good practices, and traceability from the source to the market.
Two verification schemes that focus specifically on these aspects
include the FairWild Standard and the Pennsylvania Certified Organic (PCO)
Forest Grown Verification Program. The FairWild Standard is an independent,
third-party-audited certification program.80 It is, according to
Brinckmann, “arguably the most rigorous voluntary international standard
designed specifically for sustainable wild collection of medicinal plants” (J. Brinckmann
email to C. Yearsley, March 17, 2018). The FairWild Standard has been
implemented in Europe, Africa, and Asia, but not yet in North America.
The PCO Forest Grown Verification Program is a voluntary,
third-party-audited certification scheme for non-timber forest products.84
Although it primarily focuses on organic principles, the program may address
some of the sustainability concerns about the effects of non-local plants with
limited genetic diversity on wild subpopulations of goldenseal. American
ginseng (Panax quinquefolius, Araliaceae) root, for example, is
currently available with this certification,85 and a USDA
Conservation Innovation Grant was awarded to Rural Action, Inc. and UpS to
support the development of Forest Grown Verification standards for goldenseal
and several other wild-harvested species in the eastern United States.86
Conservation of Goldenseal as a Crop Wild Relative
Techniques for cultivated and forest-grown botanical species have become
better known and more accessible (e.g., Davis and Persons 2014),47
and the positive effect of cultivation on product quality has become better
understood.87 However, little information is available about the
degree to which cultivation of goldenseal depends on wild sources of
propagating stock (i.e., goldenseal roots, rhizomes, and/or seeds).
The continued growth and viability of commercial goldenseal cultivation,
including forest-grown, will rely on the availability of germplasm from
genetically diverse and ecologically robust wild sources.88
Availability of locally adapted germplasm is particularly important for the
expansion of forest-grown operations.
Conservation of in situ wild populations of crop species and ex situ
conservation of genetically diverse and viable seed and other genetic material
(e.g., using tissue culture for clonal species or species with recalcitrant
seeds) for propagation are essential to maintaining and improving agricultural
production. Wild populations of species in cultivation may have “traits that
infer protection from environmental stressors and disease.”61 As
molecular and genetic techniques become more cost effective, they can be used
to identify and select the desired genetically beneficial traits for crop
plants.61
Ex situ conservation of goldenseal germplasm and other genetic material
is also important for restoration in its natural habitat. US government
agencies, led by the Bureau of Land Management, have created a National Seed
Strategy to provide plant material for cultivation and restoration of native plant
species.89
If goldenseal has relatively low genetic diversity within and across its
wild subpopulations, as indicated by preliminary studies,69 a major
conservation objective for this species should be to maintain genetic diversity
in isolated wild subpopulations (both large and small), and to carefully select
and store genetically diverse plants ex situ.63,69
Additionally, safeguarding the genetic variability of goldenseal will require
ensuring the persistence of even the smallest patches until the genetic
variability on a regional scale has been established.
A Path Forward
A successful
conservation plan for goldenseal must ensure that the species persists, and it
must also satisfy a persistent commercial market. A research, protection,
management, and communication plan that focuses on the distribution of
goldenseal across the landscape in patches and on the importance of each patch,
and that combines the efforts of regulators, resource managers, researchers,
industry, and conservationists, offers a way forward. We (the authors) propose
an emphasis on:
- Field inventory in
key states with the highest reported abundance of goldenseal to verify state conservation
status ranks;
- Improved protection
of wild goldenseal subpopulations across its remaining distribution;
- Population viability
analyses to better understand patch extinction risk, growth, and response to
harvest by region;
- Application of a
robust monitoring and management system of wild harvest where it can be
sustainable, and that builds on traditional, local knowledge and practices of
experienced harvesters;
- Adoption of
ecologically sound protocols for forest-grown production;
- Use of goldenseal sourced
from verifiable and traceable sustainable production systems, whether
cultivated, wild-harvested, or forest-grown (and willingness to support related
additional costs);
- Genetic studies by
region to identify and locate patches with different genotypes;
- Preservation of seed
for genotypes identified, and creation of sources of root and rhizome stock for
cultivators by region; and
- Use of new kinds of
data to track the status of goldenseal, including remote sensing, genetic
sampling, citizen science, and social media.
Conclusion
The IUCN Red List and NatureServe criteria and processes are designed to
draw upon the best available information about a species to assess the species’
risk of extinction. This includes information about a species’ population distribution,
size, and trends, as well as its ecology, habitat preferences, impacts of
threats, and existing conservation actions. Another aim of these complementary
assessments is to provide transparency and documentation in the process of
assigning a conservation rank. Conservation status assessments of economically
important species such as goldenseal can be controversial, given what is at
stake: the species’ conservation, market demand, and livelihoods of harvesters
and others involved in the industry. However, these risk-ranking protocols have
been shown to reliably forecast extinction risk even when there is some degree
of data uncertainty.90
Neither IUCN Red
List assessments nor NatureServe rankings are directly linked to legislative or
regulatory responses. Their intended use is to inform the development of
policy, legislation, and conservation actions at local, regional, national, and
international levels to prevent extinction and improve conservation status.91
In the case of goldenseal, maintaining monitoring and control of international
trade, strengthening monitoring and control of domestic wild-harvest and trade,
and improving in situ and ex situ conservation of subpopulations in the United
States and Canada will help ensure that this popular medicinal herb continues
to be available to the herbal industry and consumers.
Leah
E. Oliver is a
senior research botanist at NatureServe, where she assesses the conservation
status of plants native to North America. For more than 15 years, she has
collaborated with botanists in the United States and Canada on topics related
to threats and trends impacting plant conservation through the lens of
NatureServe and IUCN methodologies. Her research interests include medicinal
and economically important plants, endemism and rarity, bioinformatics, and
non-vascular plants.
Danna
J. Leaman, PhD,
is an ethnobotanist and conservation biologist. She co-chairs the Medicinal
Plant Specialist Group of the Species Survival Commission of the IUCN and is
currently the IUCN Red List Authority for medicinal plant assessments. She is a
member of the American Botanical Council Advisory Board, a trustee of the
FairWild Foundation, and a non-government science member of COSEWIC.
SIDEBAR
Conservation Status Assessments
Conservation
status assessments are key to ensuring the implementation of appropriate
conservation measures. These unbiased metrics of conservation condition are
used to identify which species are most at risk of extinction, and are separate
from governmental regulation and policy. For example, analyses of NatureServe’s
data have repeatedly shown that the number of species listed under the US
Endangered Species Act is an order of magnitude less than the number of at-risk
species in the United States — a disparity that stems largely from politics and
lack of resources.57 As a result, federal and subnational (i.e.,
state or provincial) organizations and government agencies in the United States
and Canada rely on NatureServe’s status assessments, called “ranks,” for
conservation prioritization. Internationally, the IUCN Red List assessments are
the most widely used methodology for conservation prioritization.
NatureServe
Ranks and IUCN Red List Categories
NatureServe is
a nonprofit biodiversity conservation organization made up of a network of more
than 80 Natural Heritage Programs in the United States and Latin America, and
provincial or regional Conservation Data Centers in Canada. The NatureServe
Network collects comprehensive information about imperiled species and entire
ecosystems, transforms the data into knowledge products and visualizations, and
provides meaning through expert analyses to guide decision-making, implement
action, and enhance conservation outcomes. NatureServe rankings are undertaken
on three geographic scales: Subnational (S ranks), National (N ranks), and
Global (G ranks).
The IUCN Red
List is organized and published by the IUCN with assessments contributed by a
large network of expert specialist groups, Red List authorities, and Red List
partners. It is considered to be the global standard for conservation status
assessments. Red List assessors assign a category of extinction risk using a
rule-based system of criteria and thresholds that accommodate both data-poor
and data-rich species. Assessment categories and criteria are applied on a
global scale,1 with adjustments for national- and regional-scale
applications.58
NatureServe’s
ranks and Red List assessments consider similar factors related to each
species’ distribution, threats, and trends, but weigh and evaluate the data
differently (Table 1).59,60 These differences produce complementary
interpretations of extinction risk and provide users with nuanced perspectives
to make informed conservation decisions. Recent publications have compared the
two systems and provide a more detailed overview of the similarities and
differences.59,61 Both systems enable assessors to objectively apply
rules for conservation status assessments. The IUCN Red List assessments
require two external reviewers of content, information quality, and consistency
with the Red List methodology.
As the North
American Red List Authority for plants and a Red List partner institution,
NatureServe has years of experience applying Red List criteria to assess
species. Similarity between the two systems makes it more cost-efficient to
assign Red List categories and global ranks at the same time rather than
separately. NatureServe’s database is broadly compatible with IUCN’s Red
List database, the Species Information Service (SIS), so the information can be
shared across platforms.
A species
assessment is considered a snapshot in time, or a reflection of the knowledge
available when the species was assessed. Due to changing threats, conservation
actions, and natural events, the conservation status of a species can change
over time. Consequently, conservation status must be regularly reviewed.
NatureServe and the Red List both recommend that assessments be updated at
least once every 10 years.
Data
Uncertainty and Risk Tolerance
The
incompleteness and imperfect quality of available information that is
considered relevant to extinction risk and the potential for assessors to be
biased toward more precautionary (i.e., risk-averse) assessments are common
concerns about assessing the conservation status of species. These concerns are
valid because complete population data are not available for most plant
species, and there is evidence suggesting that the tolerance of risk (i.e., a
tendency toward lower or higher levels of risk in assessments) is most
inconsistent for valuable, exploited species.62
Conservation
status assessments for valuable, exploited species often require more and
higher-quality data, and are more rigorously reviewed, so that the burden of
proof is more stringent than assessments for less-valued species. To this
end, NatureServe’s ranks and Red List assessments have standardized methods and
tools to address uncertainty so that the resulting rank or category is
comparable to those of other species. Additionally, NatureServe and the
IUCN Red List have steps built into their assessment methodologies to reduce
the potential for bias. NatureServe assessors, for example, are required
to use a rank calculator that weighs factor information and determines a rank. The
IUCN Red List requires consistency checks and two reviewers who are
knowledgeable about the species and the Red List process. Both NatureServe
and Red List assessments can be updated with new information or a new
interpretation of existing information.
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