COSEWIC Assessment and Status Report on the Giant Helleborine Epipactis gigantea in Canada - 2015

Photo of the flower and leaves of the Giant Helleborine
Photo: Giant Helleborine © M. Miller, 2015

Not at Risk
2015

Table of Contents

List of Figures

  • Figure 1. Giant Helleborine in its non-flowering phase (lower left) and flowering state (upper left and right). Photos by M. Miller, with permission.
  • Figure 2. North American range of Giant Helleborine.
  • Figure 3. Canadian range of Giant Helleborine, showing extant, historical, and extirpated subpopulations. Black dot = extant; orange dot = historical (unknown); open
    dot = presumed extirpated; red dot = possibly extirpated. Some dots are overlapping due to the map scale. Adapted and updated from Ministry of Environment (2013).
  • Figure 4. Dense stand of Giant Helleborine in a fully saturated, late successional habitat (mature fen) with sedges, Common Cattail (Typha latifolia) and bulrush (Schoenoplectus sp.). Roderick Haig-Brown Provincial Park. Photo by M. Miller, with permission.
  • Figure 5. Giant Helleborine growing through a dense stand of Creeping Juniper (Juniperus horizontalis) adjacent to a busy public trail at Fairmont Hot Springs.
  • Figure 6. Belt transect establishment and sampling at Holiday Creek, 2014. Note dense Giant Helleborine growth in lower photo. Photos by M. Miller and B. Kelly-McArthur, with permission.
  • Figure 7. Former occupied habitat along Peachland Creek, with recently installed silt fencing. Photo by J. Symonds, with permission.
  • Figure 8. Giant Helleborine (foreground) below encroaching native and non-native shrubs along the highway embankment near Boswell, 2013. Photo by M. Miller, with permission.
  • Figure 9. Stem of Giant Helleborine showing evidence of deer browse at McTaggart-Cowan WMA, 2014. The upper stem with inflorescence and developing fruit capsules has been removed. Photo by M. Miller, with permission.

List of Tables

  • Table 1. Giant Helleborine locations and subpopulations in British Columbia, indicating current status (extant, extirpated, or unknown), population size (number of ramets), year of last survey and source, land status, and most likely plausible threats. EO# is the corresponding Element Occurrence number used by the BC Conservation Data Centre to track a particular subpopulation (Element Occurrence). Bolded subpopulations are ones newly documented (or rediscovered in the case of EO #32) since the last status report update (White and Douglas 1998).

List of Appendices

  • Appendix 1. Threats Assessment for Giant Helleborine.
  • Appendix 2. Threat classification table for Giant Helleborine in BC. From BC Ministry of Environment (2013).

 

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Document Information

COSEWIC
Committee on the Status
of Endangered Wildlife
in Canada

COSEWIC logo

COSEPAC
Comité sur la situation
des espèces en péril
au Canada

COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows:

COSEWIC. 2015. COSEWIC assessment and status report on the Giant Helleborine Epipactis gigantea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xi + 41 pp. Species at Risk Public Registry website.

Previous report(s):

Brunton, Daniel, 1984. COSEWIC assessment and status report on the Giant Helleborine Epipactis gigantea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 26 pp.

COSEWIC. 1998. (In Press). COSEWIC assessment and status report on the Giant Helleborine Epipactis gigantea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 7 pp.

David J. White,1998. (In Press). COSEWIC status report on Giant Helleborine Epipactis gigantea in COSEWIC assessment and status report on Giant Helleborine Epipactis gigantea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 1 – 7 pp.

Production note:

COSEWIC would like to acknowledge Michael T. Miller (LGL Limited Environmental Research Associates) for writing the status report on Giant Helleborine, Epipactis gigantea, in Canada, prepared under contract with Environment Canada. This report was overseen and edited by Bruce Bennett, Co-chair of the COSEWIC Vascular Plants Specialist Subcommittee.

For additional copies contact:

COSEWIC Secretariat
c/o Canadian Wildlife Service
Environment and Climate Change Canada
Ottawa, ON
K1A 0H3

Tel.: 819-938-4125
Fax: 819-938-3984
E-mail: COSEWIC E-mail
Website: COSEWIC

Également disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur L’épipactis géant (Epipactis gigantea) au Canada.

Cover illustration/photo:

Giant Helleborine -- Photo by M. Miller, with permission.

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COSEWIC Assessment Summary

Assessment Summary – November 2015

Common name
Giant Helleborine
Scientific name
Epipactis gigantea
Status
Not at Risk
Reason for designation
In Canada, the range of this orchid is restricted to a small region of southern British Columbia. It was previously assessed as Special Concern, but additional subpopulations have been found. Therefore the species is much more abundant than previously documented. Almost half of known subpopulations occur in protected areas. It also appears to be much less threatened by orchid collectors than previously thought.
Occurrence
British Columbia
Status history
Designated Threatened in April 1984. Status re-examined and designated Special Concern in April 1998. Status re-examined and designated Not at Risk in November 2015.

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COSEWIC Executive Summary

Giant Helleborine
Epipactis gigantea

Wildlife Species Description and Significance

Giant Helleborine is a perennial, leafy-stemmed orchid up to 1 m tall that spreads from short rhizomes. Flowering stems have 3-15, 2-3 cm wide flowers that are coppery-green to reddish with brownish to purplish veins. Giant Helleborine is one of Canada’s most distinctive showy orchids and has been grown as an ornamental.

Distribution

Giant Helleborine occurs in southern British Columbia (BC) and the western United States as far east as South Dakota and Texas, with at least one collection from central Mexico. In BC, it is known from 23 subpopulations (25 “locations”) in the Columbia and Fraser river drainages, occurring east as far as Fairmont Hot Springs, north as far as Mt. Revelstoke National Park, and west as far as Cultus Lake in the Fraser Valley.

Habitat

Giant Helleborine grows on wet or moisture-receiving sites including fens, forest seeps, roadside ditches and embankments, stream banks, wet cliffs, lakeshores, and hot spring margins, in direct sunlight or shade. Sites are usually, but not always, calcareous (lime-rich).

Biology

Giant Helleborine is a long-lived perennial that reproduces both sexually (from seeds) and vegetatively (from rhizomes). Aboveground stems (ramets) emerge in the spring and die back in the fall; the flowers bloom between June and August in BC. Each fruit capsule contains thousands of tiny wind- or water-dispersed seeds. Although seedlings have been observed in the field, the most common reproductive strategy appears to be through vegetative spread. The species’ clonal nature allows it to form densely packed aggregations containing hundreds or sometimes thousands of ramets. Only a fraction of mature ramets produce flowers in any given year; many (typically >70%) produce only leafy stems. The average age of Giant Helleborine plants in Canada is estimated to be 10+ years.

The species appears to be tolerant of interspecific competition and is found in both early- and late-successional habitats. However, availability of suitable microsites for seedling recruitment and establishment may be limiting. Although occasional long-distance dispersal events evidently do occur, rescue from populations outside Canada is highly unlikely.

Population Size and Trends

There is considerable site to site variation in the size of individual subpopulations in BC. The smallest may support <20 stems, whereas many of the larger ones exceed 5,000 ramets. The largest known subpopulation is estimated to contain around a half million ramets. The estimated total size of the Canadian population is between 475,000 and 1.08 million ramets. The number of flowering stems (i.e., mature individuals) is estimated at between 50,000 and 300,000.

There are no rigorous data from which to determine recent population trends for Giant Helleborine in Canada. Over the past century, there has been a 26% decline in the total number of known Canadian subpopulations. Based on recent (confirmed or suspected) extirpations, a trend of slight but continuing decline in the total number of mature individuals is inferred.

Threats and Limiting Factors

The majority of Giant Helleborine subpopulations in Canada are currently considered secure. Where they have been identified, the most serious plausible threats are from (a) droughts that lower the water table or otherwise alter the hydrological regime, (b) habitat loss associated with land development, and (c) recreation-related disturbances such as trampling.

Protection, Status, and Ranks

COSEWIC most recently assessed this species as Not at Risk in November 2015. This species is currently is listed on the Species at Risk Act (SARA) Schedule 3 as Special Concern. However, species on Schedule 3 are not afforded any protection under SARA, and no federal management plan is in place. Ten of 23 confirmed subpopulations (43%) occur within protected areas (provincial parks, ecological reserves, wildlife management areas, and national parks) and thus are afforded some form of habitat protection (e.g., under provisions of the BC Park Act).

Globally, Giant Helleborine is ranked by NatureServe as G4 (Apparently Secure). It is ranked N3 (Vulnerable) in Canada and N3N4 (Vulnerable to Apparently Secure) in the United States. Provincially, it is ranked S3 (Vulnerable) in BC and has a Conservation Framework (CF) highest priority rank.

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Technical Summary

Scientific Name:
Epipactis gigantea
English Name:
Giant Helleborine
French Name:
Épipactis géant
 
Range of occurrence in Canada (province/territory/ocean):
British Columbia

Demographic Information

Demographic Information of the species
Summary ItemsInformation
Generation time (usually average age of parents in the population; indicate if another method of estimating generation time indicated in the IUCN guidelines(2011) is being used)Likely >10 years
Is there an inferred continuing decline in number of mature individuals?Yes
Estimated percent of continuing decline in total number of mature individuals within 5 yearsLess than 1%
Inferred percent reduction in total number of mature individuals over the last 10 years.Less than 2%
Projected percent reduction in total number of mature individuals over the next 10 years.Less than 2%
Inferred percent reduction in total number of mature individuals over any 10 year period, over a time period including both the past and the future.Less than 2%
Are the causes of the decline a. clearly reversible and b. understood and c. ceased?a. No
b. Yes
c. No
Are there extreme fluctuations in number of mature individuals?No

Extent and Occupancy Information

Extent and Occupancy Information of the species
Summary ItemsInformation
Estimated extent of occurrence (EOO).
(Based on Canada Albers Equal Area Conic Projection)
56,861 km2
Index of area of occupancy (IAO)
(Always report 2x2 grid value).
92 km2
Is the population “severely fragmented” i.e., is >50% of its total area of occupancy in habitat patches that are (a) smaller than would be required to support a viable population, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?No
Number of locations
(Note: See Definitions and Abbreviations on COSEWIC website and IUCN (Feb 2014) for more information on this term.)
25 known. Number likely to increase with additional survey efforts. A doubling of locations on public land possible, but unlikely to exceed 100
Is there an observed, inferred, or projected decline in extent of occurrence?No
Is there an inferred decline in index of area of occupancy?Yes
Is there an inferred decline in number of subpopulations?Yes; 3 subpopulations in the past 30 years (or approx. 3 generations; Table 1), for an inferred 11% decline
Is there an inferred decline in number of “locations”?
(Note: See Definitions and Abbreviations on COSEWIC website and IUCN (Feb 2014) for more information on this term.)
Yes; 3 locations in the past 30 years (or approx. 3 generations; Table 1), for an inferred 10% decline
Is there an observed or projected decline in area, extent and/or quality of habitat?Yes
Are there extreme fluctuations in number of subpopulations?No
Are there extreme fluctuations in number of “locations”?
(Note: See Definitions and Abbreviations on COSEWIC website and IUCN (Feb 2014) for more information on this term.)
No
Are there extreme fluctuations in extent of occurrence?No
Are there extreme fluctuations in index of area of occupancy?No

Number of Mature Individuals

Number of Mature Individuals of the species
SubpopulationN Stems (date of most recent estimate)
Ainsworth Hot Springs5,000-6,000 (2014)
Holiday Creek30,000-80,000 (2014)
CelistaUnknown
Columbia Lake ER8,000-9,500 (2015)
Mara Meadows ER1,300-1,500 (2010)
White Lake PP1,000-2,000 (2010)
Mabel Lake30-40 (2010)
Roderick Haig-Brown PP380,000-890,000 (2014)
Bilbo’s Bog200 (2010)
Cranberry Creek23,000-57,000 (2014)
Cultus Lake PP300 (2004)
Fairmont Hot Springs6,500-11,500 (2013)
Kent1,000-2,000 (2011)
Revelstoke, east of500-600 (2014)
Kearns Creek-Mahoney Lake0? (2010)
Mountain Slough, island40 (2010)
Hopyard Hill, island3 (2010)
Okanagan Falls27 (2013)
NaramataUnknown
Okanagan Lake west (Camp Owaissi)243 (2013)
Skaha Lake Southwest804 (2013)
Hardy Falls Park0? (2013)
Pilot Bay PP12,200 (2014)
Cape Horn900 (2013)
McTaggart-Cowan WMA320 (2014)
Tappen5,000-10,000 (2014)
Park Rill12 (2012)
Total475,000-1,080,000 (of which an estimated 50,000-300,000 were flowering [i.e. “mature”] stems in 2014)

Quantitative Analysis

Quantitative Analysis of the species
Summary ItemsInformation
Probability of extinction in the wild.Not available

Threats (actual or imminent, to populations or habitats, from highest impact to least)

  1. Droughts (increase in frequency and severity of)
  2. Habitat loss associated with land development
  3. Recreation-related disturbances (e.g., trampling)

Was a threats calculator completed for this species and if so, by whom?
Yes, original review by BC Ministry of Environment (2013), reviewed and revised by Bruce Bennett, Dave Fraser, Mike Miller, Stephanie Pellerin, and Karen Timm (March 24, 2015) (Appendix 1).

Rescue Effect (immigration from outside Canada)

Rescue Effect of the species
Summary ItemsInformation
Status of outside population(s) most likely to provide immigrants to Canada.

Populations in Washington, Idaho,

and Montana are rated as Vulnerable (S3)

Is immigration known or possible?Unknown and unlikely
Would immigrants be adapted to survive in Canada?Probably
Is there sufficient habitat for immigrants in Canada?Probably
Are conditions deteriorating in Canada?
See Table 3 (Guidelines for modifying status assessment based on rescue effect) 
Yes
Are conditions for the source population deteriorating?
See Table 3 (Guidelines for modifying status assessment based on rescue effect) 
Yes
Is the Canadian population considered to be a sink?
See Table 3 (Guidelines for modifying status assessment based on rescue effect) 
No
Is rescue from outside populations likely?No

Data-Sensitive Species

Data-Sensitive information of the species
Summary ItemsInformation
Is this a data sensitive species?No

Status History

COSEWIC: Designated Threatened in April 1984. Status re-examined and designated Special Concern in April 1998. Status re-examined and designated Not at Risk in November 2015.

Status and Reasons for Designation:

Status:
Not At Risk
Alpha-numeric code:
Not applicable
Reasons for designation:
In Canada, the range of this orchid is restricted to a small region of southern British Columbia. It was previously assessed as Special Concern, but additional subpopulations have been found. Therefore the species is much more abundant than previously documented. Almost half of the known subpopulations occur in protected areas. It also appears to be much less threatened by orchid collectors than previously thought.

Applicability of Criteria

Criterion A (Decline in Total Number of Mature Individuals):
Does not meet criteria. Declines do not meet thresholds.
Criterion B (Small Distribution Range and Decline or Fluctuation):
Does not meet criteria. Although IAO is below the threshold for Endangered, the species occurs in greater than 10 locations, is not severely fragmented, and does not undergo extreme fluctuations.
Criterion C (Small and Declining Number of Mature Individuals):
Does not meet criteria. Exceeds thresholds for number of mature individuals.
Criterion D (Very Small or Restricted Population):
Does not meet criteria.
Criterion E(Quantitative Analysis):
Not applicable. Not done.

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Preface

Significant new survey information on Giant Helleborine has become available since the last Status Report update (White and Douglas 1998). Currently there are 23 subpopulations confirmed as extant, a 77% increase over the 13 reported by White and Douglas (1998). All but two of the 13 subpopulations reported by White and Douglas (1998) have updated observations as recent as 2010. The current status of two subpopulations--Naramata and Celista--is unknown.

The subpopulation at Cultus Lake (EO #28), first reported in 1926, was not included in the 1998 Status Report but was last surveyed in 2004 with approximately 300 plants observed. The Columbia Lake site was also not mentioned in the 1998 update status report, even though the first observation was in 1978. This subpopulation was confirmed in 2013. The Ainsworth Hot Spring subpopulation had not been reported since the 1950s and was presumed extirpated, but this site was confirmed as extant in 2014. Kearns Creek and Mahoney Lake, which were considered separate sites in the 1998 report, have been determined to be based on the same historical observation. Recent searches at this site (in 2009 and 2010) have been unsuccessful and this subpopulation is likely extirpated. Also now extirpated is the subpopulation at Vernon, while the Okanagan Falls subpopulation may have declined.

Since the 1998 status update, 13 newly discovered or rediscovered subpopulations have been observed in the province. Most of these are in the Columbia River drainage (Okanagan and Shuswap regions), with a few in the lower Fraser Valley. A subpopulation first reported near Peachland in 2010 has not been observed again in recent years and is possibly extirpated. The total reported Canadian population in 1998 was estimated at 3,175 to >12,250 stems, or ramets. The estimated total population size in 2014 was between 475,000 and 1.08 million ramets (approximately 10-20% of which were flowering ramets). This increase is likely due to greater counting and search effort, rather than to any recent population increase.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2015)

Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.
Extinct (X)
A wildlife species that no longer exists.
Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.
Endangered (E)
A wildlife species facing imminent extirpation or extinction.
Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.
Special Concern (SC)
(Note: Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.)
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.
Not at Risk (NAR)
(Note: Formerly described as “Not In Any Category”, or “No Designation Required.”)
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.
Data Deficient (DD)
(Note: Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” [insufficient scientific information on which to base a designation] prior to 1994. Definition of the [DD] category revised in 2006.)
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.

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Wildlife Species Description and Significance

Name and Classification

Scientific Name: Epipactis gigantea Douglas ex Hooker

Synonyms: Amesia gigantea(Douglas ex Hooker) A. Nelson & J.F. Macbride;
Helleborine gigantea (Douglas ex Hooker) Druce

Common English Names: Giant Helleborine, Stream Orchid, Chatterbox

Common French Name: épipactis géant

Family Name: Orchidaceae (Orchid Family)

Giant Helleborine is a well-established taxon with no described subspecies or varieties and no taxonomic complications. Two distinct colour forms of this species have been described in California: Epipactis giganteaforma rubrifolia P.M. Brown, with deep red stems and leaves, and E. gigantea forma citrina P.M. Brown, with lemon-yellow flowers (Brown and Argus 2002).

Morphological Description

Giant Helleborine (Figure 1) is a perennial herb, 30–100 cm tall, with a short rhizome and thick clustered roots that give rise each year to one or several leafy shoots (ramets). The numerous leaves are lance-shaped to egg-shaped, 5–20 cm long and 2–7 cm broad. They are unstalked with bases that sheath the stem. Flowering ramets have 3–15 showy, 2–3 cm wide flowers usually on one side of the stem. The sepals and petals are coppery-green to reddish with brownish to purplish veins. The lower petal (lip) is 1.5–2 cm long and sac-like at the base, the sac with prominent, raised, purplish lines leading to the base. The fruit, a nodding capsule, is elliptic in shape, 2–3 cm long, and contains thousands of tiny seeds (Douglas et al. 2001; Brown and Argus 2002).

The tall stems with reddish flowers in the leaf axils make this one of our most distinctive orchids. When in flower, it is not easily confused with any other native species, although it may be confused with the introduced Broadleaf Helleborine (Epipactis helleborine). Besides being abundant in some places where Giant Helleborine grows in the Fraser Valley, Broadleaf Helleborine now occurs in the interior of British Columbia (Lomer pers. comm. 2015). In a vegetative (non-flowering) state, Giant Helleborine may be confused in the field with other, co-occurring monocots with similar leaves such as Large False Solomon’s Seal (Maianthemum racemosum).

Figure 1. Giant Helleborine in its non-flowering phase (lower left) and flowering state (upper left and right). Photos by M. Miller, with permission.
three separate images of the Giant Helleborine
Long description for Figure 1

Three photos showing (a) the non-flowering phase of the Giant Helleborine (leaves), (b) a single Giant Helleborine flower, and (c) a stand of flowering Giant Helleborine.

Population Spatial Structure and Variability

Giant Helleborine is a self-compatible, clonal orchid. Reproduction routinely involves a single colonization event followed by asexual propagation and selfing (Argue 2012). The species occurs in discrete subpopulations scattered over a broad geographic range and appears to possess an unusually large amount of genetic variation (Thornhill 1996). Occurrences in California are genetically different from one another, suggesting minimal gene flow among occurrences (Thornhill 1996). There are no data available on genetic variability or characteristics of Giant Helleborine in British Columbia (BC).

Designatable Units

The Canadian population is being treated as a single designatable unit. Although the known range spans two COSEWIC National Ecological Areas (Southern Mountain and Pacific), there is currently no evidence of morphological or genetic differentiation that would warrant their separation.

Special Significance

Giant Helleborine is one of Canada’s most showy native orchids yet is rarely seen in the wild. In addition to being of conservation concern in BC (BC Ministry of Environment 2013; BC Conservation Data Centre 2014b), Giant Helleborine is considered a species of conservation concern by most U.S. state heritage programs including Arizona, Colorado, Idaho, Montana, New Mexico, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, and Wyoming (see Non-Legal Status and Ranks; NatureServe 2014). The species has been used as an ornamental (NatureServe 2014) and can be purchased from nurseries, including from nurseries as far afield as the UK (e.g., Edrom Nurseries 2014). Giant Helleborine is used by herbalists (e.g., Kane 2015) for pain and anxiety relief (Zapotoczny 2015), and other species of Epipactis are used to treat arthritis and gout.

Because of its specific hydrological requirements, Giant Helleborine has the potential to be an important indicator species for wetland integrity.

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Distribution

Global Range

Giant Helleborine is native to North America, although some recent taxonomic work indicates that its global range may include Asia (India, Japan, and China including Tibet). The occurrence in Asia is based on Royle’s Epipactis, Epipactis royleana “being given as a synonym in a study of the Monocotyledoneae of Karakorum (Dickoré 1995) and an embryologic study (Vij et al. 1999)” (Brown and Argus 2002). At the present time Giant Helleborine and Royle’s Epipactis are considered separate species (The Plant List 2010).

The North American range of Giant Helleborine extends from southern BC through the western United States, reaching eastward to South Dakota and Texas (Figure 2). There has also been at least one collection made in central Mexico (NatureServe 2014). Giant Helleborine is most abundant in California, where it is the most widely distributed orchid in the state (Coleman 1988; Hickman 1993; NatureServe 2014). Throughout its broader range, it occurs infrequently as isolated occurrences but can be locally abundant (Rocchio et al. 2006). Erroneous reports exist for Nebraska (Rocchio et al. 2006; Enns pers. comm. 2014; Steinauer pers. comm. 2014), and Kansas (Freeman pers. comm. 2014; Treher pers. comm. 2014).

Figure 2. North American range of Giant Helleborine.
Map of North America
Long description for Figure 2

Map of the North American range of the Giant Helleborine, which extends from southern British Columbia through the western United States, reaching eastward to South Dakota and Texas. There has also been at least one collection made in central Mexico.

Canadian Range

In Canada, Giant Helleborine occurs only in southern BC (Figure 3), which represents the northern extent of its North American range (Figure 2). Within BC, it is known from the Columbia and Fraser river drainages, occurring east as far as Fairmont Hot Springs, north as far as Mt. Revelstoke National Park, and west as far as Cultus Lake (Brunton 1984; White and Douglas 1998; BC Ministry of Environment 2013; BC Conservation Data Centre 2014b). Its BC range spans several distinct biogeoclimatic zones including the Bunchgrass (BG), Ponderosa Pine (PP), Interior Douglas-fir (IDF), Interior Cedar–Hemlock (ICH), and Coast Western Hemlock (CWH) zones.

Figure 3. Canadian range of Giant Helleborine, showing extant, historical, and extirpated subpopulations. Black dot = extant; orange dot = historical (unknown); open dot = presumed extirpated; red dot = possibly extirpated. Some dots are overlapping due to the map scale. Adapted and updated from Ministry of Environment (2013).
Map of southern BC
Long description for Figure 3

Map of the Canadian range of the Giant Helleborine, showing the locations of extant, historical, and extirpated subpopulations. In Canada the Giant Helleborine occurs only in southern British Columbia, where it is known from the Columbia and Fraser river drainages, occurring east as far as Fairmont Hot Springs, north as far as Mount Revelstoke National Park, and west as far as Cultus Lake.

Thirty-four subpopulations have been reported in Canada since Giant Helleborine was first reported in the late 1800s (BC Ministry of Environment 2013). Twenty-three of these are known to be extant (Figure 3). There are two historical (unknown), two possibly extirpated, and seven presumed extirpated subpopulations of Giant Helleborine in Canada (Table 1).

Table 1. Giant Helleborine locations and subpopulations in British Columbia, indicating current status (extant, extirpated, or unknown), population size (number of ramets), year of last survey and source, land status, and most likely plausible threats. EO# is the corresponding Element Occurrence number used by the BC Conservation Data Centre to track a particular subpopulation (Element Occurrence). Bolded subpopulations are ones newly documented (or rediscovered in the case of EO #32) since the last status report update (White and Douglas 1998).
LocationEO#Subpopulation/EO nameStatusNo. of stems (ramets)Last survey & sourceLand statusPlausible threats
1. Ainsworth32Ainsworth Hot SpringsExtant5000-60002014
Miller and Kelly-McArthur
PrivateResort development, hydrological alterations
2. Boswell-Hwy 3A19Holiday CreekExtant30,000-80,000 (multiple sites)2014
Miller and Kelly-McArthur
Provincial CrownShrub ingrowth, invasive species, highway maintenance
3. Boswell-private19Holiday CreekExtantIncluded under Boswell-Hwy 3A estimate2014
Miller and Kelly-McArthur
PrivateHabitat loss, hydrological alterations
4. Boswell-transmission corridor19Holiday CreekExtantIncluded under Boswell-Hwy 3A estimate2013
Miller and Hulland
Provincial CrownTransmission corridor maintenance
4. Boswell-transmission corridor4CelistaUnknownUnknown1994
Ceska
UnknownUnknown
5. Columbia Lake18Columbia Lake ERExtant8000-9,500 (in two patches)2015
Kelly-McArthur
Ecol. ReserveNone
6. Mara Meadows3Mara Meadows ERExtant1,300-1,5002010
Dyer and Bunge
Ecol. ReserveNone
7. White Lake7White Lake PPExtant1,000-2,0002010
Dyer and Bunge
Provincial ParkNone
8. Mabel Lake11Mabel LakeExtant30-402010
Dyer and Bunge
Provincial CrownRange use
9. Adams River13Roderick Haig-Brown PPExtant380,000-890,0002014
Miller
Provincial ParkNone
10. Upper Violet Creek PP17Bilbo’s Bog, Larch HillsExtant2002010
Coffey
Provincial ParkRecreational ATV use
11. Cranberry Creek26Cranberry CreekExtant23,000-57,0002014
Miller and Kelly-McArthur
Provincial CrownNone
12. Cultus Lake28Cultus Lake PPExtant3002004
Lomer
Provincial ParkNone
13. Fairmont Hot Springs1Fairmont Hot Springs ResortExtant6,500-11,500 (multiple sites)2013
Antifeau
PrivateLand development, hydrological alterations
14. Agassiz21KentExtant1,000-2,0002011
Lomer
Federal CrownNone
15. Revelstoke NP24Revelstoke, east ofExtant500-6002014
Miller
National Park / Highway ROWHighway ROW maintenance
15. Revelstoke NP5Kearns Creek-Mahoney LakeLikely extirpated0?2009 & 2010
Dyer and Bunge
Private or Highway ROW?Hydrological alterations, road ROW maintenance
16. Lower Fraser River 120Mountain Slough, islandExtant402010
Lomer
Provincial CrownFlooding, deer browsing
17. Lower Fraser River 222Hopyard Hill, islandExtant32010
Lomer
Provincial CrownFlooding, deer browsing
18. Okanagan Falls8Okanagan FallsExtant27 (multiple sites)2013
Symonds
PrivateRange use, residential development, haying
18. Okanagan Falls2Naramata, north ofUnknownUnknown1977
Ray
PrivateUnknown
19. West Okanagan Lake23Camp OwaissiExtant2432013
Symonds and Leathem
PrivateInvasive species
20. Southwest Skaha Lake25Southwest Skaha LakeExtant8042013
Symonds and Leathem
UnknownInvasive species, hiker trampling
20. Southwest Skaha Lake-Peachland Creek (Hardy Falls Park)Likely extirpated0?2013
Symonds and Leathem
Regional ParkHydrological alterations, hiker trampling
21. Pilot Bay PP9South of Boomer’s LandingExtant12,200 (multiple sites)2014
Miller and Kelly-McArthur
Provincial ParkHydrological alterations, hiker trampling
22. Cape Horn10Cape Horn-MacDonald BeachExtant9002013
Gall and Hulland
PrivateResidential development, hiker trampling
23. Northeast Skaha Lake-McTaggart-Cowan WMAExtant320 (multiple sites)2014
Miller, Symonds, Weston, and Bunge
Wildlife Management AreaHiker trampling, invasive species
24. Shuswap Lake27TappenExtant5,000-10,0002014
Miller
Provincial CrownRoad ROW maintenance
25. White Lake Grasslands PA29Park RillExtant122012
Bunge
Provincial Protected AreaRange use
25. White Lake Grasslands PA6Enderby Cliffs ParkPresumed extirpatedUnknown1954
Taylor
UnknownUnknown
25. White Lake Grasslands PA15VernonPresumed Extirpatedextirpated2014
Miller
PrivateExtirpated by housing development
25. White Lake Grasslands PAN/ALower Arrow LakePresumed ExtirpatedUnknownUnknownUnknownFlooded by dam construction
25. White Lake Grasslands PAN/AHowser (Duncan Lake)Presumed ExtirpatedUnknownUnknownUnknownFlooded by dam construction
25. White Lake Grasslands PAN/ARadium Hot SpringsPresumed ExtirpatedUnknownUnknownUnknownDestroyed by resort development
25. White Lake Grasslands PAN/AOsoyoosPresumed extirpatedUnknown1877UnknownUrban development
25. White Lake Grasslands PAN/ASicamousPresumed extirpatedUnknown1954UnknownUnknown

Total count: 475,000-1,085,000

Extent of Occurrence and Area of Occupancy

Giant Helleborine has an estimated extent of occurrence (EOO) of 56,861 km2 (Wu pers. comm. 2014; Figure 3). The index of area of occupancy (IAO) for extant sites is 92 km2 (23 2 x 2 km grids). The EOO estimate is not affected by excluding the two historical sites at Celista and Naramata as well as the two likely extirpated sites at Kearns Creek and Peachland Creek. Exclusion of these sites does not affect the EOO estimate. The biological area of occupancy (AO), or the area actually occupied, is estimated to be 0.07 km2 or 7 hectares.

Search Effort

Field verification of Giant Helleborine sites was conducted when the plant was flowering over two field seasons (2013 and 2014). Surveys were conducted by the report writer (M. Miller) with supplemental contributions from staff at the BC Conservation Data Centre, BC Parks, BC Ministry of Environment, BC Ministry of Forests, Lands & Natural Resource Operations, and from volunteers. The survey spanned most of the geographic regions of BC where Giant Helleborine is known to occur, including the East and West Kootenays, south Okanagan, north Okanagan, and Columbia-Shuswap. Sites in the Fraser Valley were not visited; however, these have all been verified since 2004, and most as recently as 2010/2011 (Table 1).

A total of 17 localities were visited in 2013 and 2014 (Table 1). Of the 17 sites surveyed, 14 represented previously known extant subpopulations and one (McTaggart-Cowan Wildlife Management Area [WMA]) is a newly discovered subpopulation supporting multiple discrete colonies. Two subpopulations (Vernon and Ainsworth Hot Springs) were believed to be extirpated or likely extirpated. The Vernon subpopulation was confirmed as extirpated. However, the Ainsworth site was found to be extant, supporting a vigorous subpopulation of several thousand ramets. This subpopulation had not been verified since the 1950s (Table 1).

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Habitat

Habitat Requirements

Giant Helleborine grows on wet or moisture-receiving sites including fens, forest seeps, roadside ditches and embankments, stream banks, wet cliffs, lakeshores, and hot spring margins, in direct sunlight or shade (Brunton 1984, 1986; Coleman 1988; Mancuso 1991; Hornbeck et al. 2003; BC Ministry of Environment 2013). Sites are often, though not always, calcareous (lime-rich) and are typically associated with minerotrophic habitats--localized areas fed by spring or surface water that has flowed over or through rocks or other minerals, in the process acquiring dissolved chemicals that raise the nutrient levels and reduce acidity.

Nevertheless, little is known about the soil requirements of Giant Helleborine (Rocchio et al. 2006). The species tolerates a wide soil pH range in California (Coleman 1988). Mantas (1993) found a positive correlation between extractable soil potassium (K+) concentration and ramet height for Giant Helleborine occurrences in Montana fens. In Colorado and Wyoming, occurrences grow in alkaline or calcareous mineral soils (Rocchio et al. 2006). The species appears to do well at the margins of hot springs that have calcium carbonate precipitate in the water derived from limestone bedrock or exposed tufa (porous rock composed of calcium carbonate; Brunton 1986; Hornbeck et al. 2003), although it is not restricted to thermal waters. Some of the largest and most robust sites in BC are in cool environments such as fens (Miller pers. obs. 2014). In riparian areas, flooding may create sites for propagules or clonal spread (Levine 2000). Its close association with localized ground or surface water sources may help account for Giant Helleborine’s distinctly patchy and fragmented distribution across its range.

Within the constraints imposed by its need for a constant supply of water at the roots, Giant Helleborine exhibits a rather broad ecological range. It is one of the few orchids that grow in the desert (California), albeit in wet habitats. Its global range includes life zones ranging from desert to montane (Rocchio et al. 2006). In BC, its range spans the Bunchgrass, Ponderosa Pine, Interior Douglas-fir, Interior Cedar – Hemlock, and Coastal Western Hemlock biogeoclimatic zones at elevations up to 1375 m (Brunton 1986; White and Douglas 1998; BC Conservation Data Centre 2014b). Within these zones, it is found in microsite types ranging from lakeshore spray zones (Cultus Lake, Skaha Lake, Okanagan Lake, Kootenay Lake), to road embankments (Tappen, Revelstoke National Park, Ainsworth, Holiday Creek), to sedge fens (Mara Meadows, White Lake, Mabel Lake, Adams River, Cranberry Creek, Bilbo’s Bog), to riverine islands (lower Fraser River), to lime-encrusted cliff seepages (Kootenay Lake), to hot spring tufa deposits (Ainsworth and Fairmont Hot Springs), to seasonally moist shrubby draws on dry Ponderosa Pine (Pinus ponderosa) slopes (McTaggart-Cowan WMA near Penticton), to bunchgrass grasslands (White Lake PA), to riparian thickets (Okanagan Falls).

Habitat Trends

Historically, urbanization and other forms of land development (e.g., hydroelectric reservoirs, hot spring resorts), combined with hydrological alterations, have been the leading factors in declining habitat availability and habitat loss for Giant Helleborine in Canada (Table 1). The one known instance of recent habitat extirpation (Vernon) was directly attributable to residential development, albeit within city limits. For a minority of extant sites, namely those occurring on private lands (Table 1), residential, lakeshore, or commercial (hot springs) development may be producing declines in habitat availability or quality, although there is no current direct evidence for this. Most other extant sites occur within protected areas or on provincial or federal crown lands where further land development is not anticipated and/or where habitat trends appear generally stable. Possible exceptions to this are areas, such as at Holiday Creek, Pilot Bay, and Kearns Creek, where recent or historical changes to the hydrological regime may be resulting in the drying of habitats as well as facilitating increased shrub and tree encroachment into occupied habitats. In the case of Holiday Creek, successional changes have been attributed to local upslope processes (water extraction on adjacent private property), whereas at Pilot Bay there may be lingering impacts associated with the damming of Kootenay Lake in the 1950s, and the subsequent lowering of the permanent high water mark (Hulland pers. comm. 2014).

It is difficult to identify general habitat trends that apply consistently across the Canadian range, both because the known range encompasses such a broad area (>58,000 km2) and because Giant Helleborine occurs in a wide variety of habitats where the most immediate habitat influences tend to be specific and localized. Generally speaking, it can be presumed that along with the widespread valley-bottom urban and agricultural development that has occurred in the Columbia, Kootenay, Okanagan, and Fraser river watersheds, there has been a parallel decline in the areal extent of preferred natural habitats such as seeps, fens, lakeshores, and hot springs. At the same time, these inferred declines may have been somewhat offset historically by the accidental creation of ruderal (disturbed) habitats through road construction and ditching, given that Giant Helleborine shows evidence of being able to colonize (and dominate) such disturbances under the right conditions (such as where roads cut across an aquifer; Coleman 1998).

The Colorado Natural Heritage Program states that the general trend of Giant Helleborine is “one of decline due principally to habitat loss” (Rocchio et al. 2006).

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Biology

The biology of Giant Helleborine has been the subject of various technical reports and some peer-reviewed articles and graduate theses (e.g., Mantas 1993; Thornhill 1996). Probably the most comprehensive current review of published and unpublished information is that provided by Rocchio et al. (2006). Much of the information in the following sections is derived from this review, supplemented by provincial species accounts (BC Ministry of Environment 2013; BC Conservation Data Centre 2014b) and from field observations of the report writer and other individuals involved directly with monitoring Giant Helleborine in BC.

Life Cycle and Reproduction

Giant Helleborine is a long-lived perennial that reproduces both sexually (from seeds) and asexually (from rhizomes). Aboveground stems (ramets) emerge in the spring and die back in the fall. Individual ramets may alternate between a reproductive and non-reproductive state from year to year.

Flowering rates vary widely from year to year, with non-reproductive ramets generally making up about 70-90% of most patches in a given year. The determinants of flowering and fruiting success are not well understood, although climatic factors likely play a significant role. In addition to temporal variation in flowering, individuals that flower also vary in fruit set, with variability in fruit set is thought to be partly attributable to summer weather conditions (high rainfall) that reduce pollinator visitation (Mantas 1993). In a two-year study of flowering and fruiting success in Montana fens, Mantas (1993) found that the probability of a non-flowering juvenile maturing to a flowering adult in any given year was 0.03 to 0.05, while the probability of a flowering adult producing fruit capsules was 0.06 to 0.63.

Each mature fruit capsule contains thousands of tiny seeds. The seeds have no endosperm or seed coat and are relatively short-lived in ambient temperatures (Thornhill 1996). Arditti et al. (1981) reported average germination rates in the laboratory of 20%. No data exist on germination success under natural field conditions, although seeds require mycorrhizae for germination. It is unknown how long seeds remain viable in the soil, or how long seeds take to germinate and develop visible shoots in the field (Rocchio et al. 2006).

Although seedlings have been observed in the field, the most common reproductive strategy appears to be asexual. Vegetative reproduction in Giant Helleborine occurs by means of short, fibrous rhizomes (Brown and Argus 2002) that grow laterally across the substrate to form either a dense monoculture or a looser colony. Plants can reproduce asexually at a rate of up to three new above-ground ramets per season (under greenhouse conditions; Thornhill 1996). The connections between Giant Helleborine parent and daughter ramets are often severed within one season (Thornhill 1996). However, demographic studies of Giant Helleborine are lacking, and it is unknown at what age plants begin to spread vegetatively or how long it takes before the plants reach reproductive age or size (Rocchio et al. 2006).

There is no information on the average age of Giant Helleborine plants in Canada or elsewhere. The plant’s perennial rhizomatous nature, its apparent slow maturation rate from seedling to juvenile to mature ramet, evident ramet longevity, and complex life cycle involving progression and reversion between life stages suggest that individuals are very long-lived. It appears probable that the average age of mature individuals exceeds 10 years.

Physiology and Adaptability

Although Giant Helleborine thrives under a range of climatic regimes, it is consistently associated with moist or wet minerotrophic habitats and appears to require a constant supply of water. It is easy to cultivate as long as a wet habitat can be provided (Cronquist et al. 1977). In cultivation, the species can spread rapidly, and flowering stems that are produced on rhizomes often flower in their second year. Under favourable conditions, such as a garden setting, the species can be aggressive (Fraser pers. comm. 2015). Seeds require soil mycorrhizae (fungal symbionts) for germination (Arditti et al. 1981; Dressler 1981).

Arditti et al. (1981) noted that shade is needed for germination, but that plants prefer sunny environments at later stages of development. Coleman (1988, 2002) notes that Giant Helleborine grows under tree canopies, but many northern sites are found in full sun. In BC, sites are located in both shaded and sunny situations, although the largest and most vigorous subpopulations tend to be on sunny sites or sites with partial shade.

There is no strong evidence that disturbance is necessary for successful establishment, but the species can colonize bare ground and appears capable of exploiting disturbances when they occur by pre-emptively capturing resources and maximizing vegetative growth (Brunton 1986; Rocchio et al. 2006). Examples of early successional habitats where Giant Helleborine forms dominant stands include tufa mounds and road embankments. Once established, the rhizomes may be able to tolerate moderate levels of surface disturbance. For example, in 2014, along the shoulder of TransCanada Highway in Revelstoke National Park, ramets of Giant Helleborine were observed emerging through sand piles left behind by the previous winter’s snow ploughs (Miller pers. obs. 2014).

Dispersal and Migration

Seeds are dispersed by wind and possibly water (Dressler 1981). There is little specific information on Giant Helleborine dispersal ecology. However, the presence of apparently suitable but unoccupied habitat in close proximity to many occupied sites suggests that the species is slow to colonize new areas. Whether this is due to inefficient seed dispersal mechanisms, a lack of mycorrhizal symbionts in the soil, or inadequate light/moisture conditions for seed germination and seedling recruitment, is unclear. At the same time, the occurrence of disjunct subpopulations scattered over a broad geographic range indicates that occasional successful long-range dispersal events do occur. Thornhill (1996) and Rocchio et al. (2006) note that long-range dispersal ability in conjunction with high genetic variability and self-compatibility (ability to self-pollinate) may enable Giant Helleborine to colonize, and adapt to, a variety of geographically isolated habitats.

Interspecific Interactions

Pollination is primarily by syrphid flies (Argue 2012), which are described as specialist pollinators of Giant Helleborine (Luer 1975).

In BC, field observations indicate that the upper stems of Giant Helleborine are frequently grazed by Mule and/or White-tailed Deer (Odocoileus hemionus and O. virginianus). The relative impact of herbivory tends to be highest within small subpopulations, where in extreme cases over 90% of the plants may be cropped, resulting in the loss up to 100% of the seed crop production.

Brunton (1986) indicates that Giant Helleborine is not a good competitor. However, Schassberger (1988) and Levine (2000) both suggest that Giant Helleborine is tolerant of interspecific competition, and observations in BC appear to support this (Figure 4). At several BC sites, the species forms colonies so dense that they actually exclude all other vegetation. At Fairmont Hot Springs, one subpopulation has persisted for several decades interspersed with, and overtopped by, a dense stand of Creeping Juniper (Juniperus horizontalis). This juniper stand in fact appears to be shielding Giant Helleborine from the threat of human foot traffic in this heavily visited resort area (Figure 5). In South Dakota, Giant Helleborine has persisted despite periods of disturbance associated with recreation, invasion by exotic plants, mowing, and weed control, further suggesting a level of tolerance toward interspecific competition following disturbance (Rocchio et al. 2006).

Figure 4. Dense stand of Giant Helleborine in a fully saturated, late successional habitat (mature fen) with sedges, Common Cattail (Typha latifolia) and bulrush (Schoenoplectus sp.). Roderick Haig-Brown Provincial Park. Photo by M. Miller, with permission.
Image of Giant Helleborine habitat
Long description for Figure 4

Photo of a dense stand of the Giant Helleborine in a fully saturated, late successional habitat (mature fen) with sedges, Common Cattail and bulrush.

Figure 5. Giant Helleborine growing through a dense stand of Creeping Juniper (Juniperus horizontalis) adjacent to a busy public trail at Fairmont Hot Springs.
Image of Giant Helleborine habitat
Long description for Figure 5

Photo showing Giant Helleborine growing through a dense stand of Creeping Juniper adjacent to a busy public trail at Fairmont Hot Springs.

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Population Sizes and Trends

Sampling Effort and Methods

Estimating population sizes for Giant Helleborine is challenging due to the species’ vigorous clonal habit, which can result in very dense patches of ramets spread over large (>1 ha) areas and containing many tens of thousands of stems. Survey approaches have varied over the years depending on the subpopulation size and extent, and the individual surveyor. For smaller subpopulations (<200 ramets or so), a complete enumeration of visible ramets was generally attempted. For larger subpopulations (>200 ramets), rough visual estimates were usually made. It should be noted that not everyone contributing count data in previous years distinguished between flowering and non-flowering ramets in their estimates; consequently, counts of mature individuals (i.e., flowering ramets) are unavailable for some subpopulations.

In surveys conducted by M. Miller in 2014, abundance was estimated in one of three ways depending on subpopulation size, extent, and configuration: (i) by counting all visible ramets; (ii) by visual estimate; or (iii) via randomized subsampling of the subpopulation. Complete ramet counts were carried out whenever feasible (i.e., when the subpopulation did not exceed a couple of hundred ramets in size). For visual estimates, the usual approach was to count the number of flowering and non-flowering ramets within a representative (with respect to stem density) 1 m2 plot, then extrapolate this number to the larger subpopulation based on the total patch area occupied.

In the more formal subsampling approach, employed to minimize observer bias when sampling the largest subpopulations (>~5,000 ramets), 1 m2 plots were randomly located through the subpopulation (either through blind stick tosses or using belt quadrats sampled at predetermined random intervals; Figure 6). All ramets (flowering and non-flowering) within the sample plots were enumerated. The mean numbers of flowering and non-flowering ramets per m2 were estimated, together with the standard deviations and 90% confidence intervals. These values were then extrapolated to the total patch area occupied to obtain 90% confidence intervals for the entire subpopulation. For larger areas, areal extent was estimated using a GPS to delimit the subpopulation perimeter. This more rigorous sampling approach tended to yield considerably higher subpopulation estimates than previous cursory estimates (usually consisting of a quick visual estimate in the case of very large subpopulations). For example, the Adams River subpopulation is presently estimated to contain around a half million ramets, compared to the previous estimate of “at least 5,000” plants (BC Conservation Data Centre 2014a). Similarly, stratified-random sampling at the Cranberry Creek site indicates that this subpopulation supports >20,000 ramets, in contrast to the previous reported estimate of 100-500 plants (BC Conservation Data Centre 2014a).

Figure 6. Belt transect establishment and sampling at Holiday Creek, 2014. Note dense Giant Helleborine growth in lower photo. Photos by M. Miller and B. Kelly-McArthur, with permission.
Two images of researches in Giant Helleborine habitat
Long description for Figure 6

Two photos illustrating the establishment of a belt transect for sampling the Giant Helleborine at Holiday Creek (refer to report text for details on how sampling was carried out).

Abundance

As noted above, the size of the Canadian population is difficult to assess accurately. The plants often grow in densely packed aggregations (almost resembling grass in some areas), large portions of which may arise from the same rhizome. The species’ clonal nature also makes it difficult to estimate the number of genetic individuals at a particular site, which would entail intensive genetic sampling of stems. For this reason, abundance estimates are typically given as the number of aboveground ramets, not the number of genetically individual plants (genets). NatureServe (2014) estimates that the actual number of genets is small but there are many thousands of ramets of Giant Helleborine across its range. The total size of the number of ramets in the Canadian population, derived from estimates for BC subpopulations surveyed since 2004 (Table 1), is between 475,000 and 1.08 million ramets. The number of mature individuals (i.e., flowering stems) is estimated at between 50,000 and 300,000 (or about 10-30 percent of the number of ramets). These values, which are probably conservative, represent a substantial increase from earlier status report estimates (Brunton 1984; White and Douglas 1998). The increase is due largely to the recent discovery of new subpopulations combined with more rigorous methods estimating population sizes.

There is considerable variation in the size of individual subpopulations in BC. The smallest sites (e.g., Park Rill, Hopyard Hill) may support <20 ramets, whereas many of the larger sites (e.g., Roderick Haig-Brown Provincial Park, Cranberry Creek, Holiday Creek, Pilot Bay, Fairmont Hot Springs) exceed 5,000 ramets. The largest known subpopulation, at Roderick Haig-Brown Provincial Park, is estimated to contain around a half million ramets (Table 1).

Fluctuations and Trends

Globally, NatureServe (2014) states that the general trend of decline is due principally to habitat loss and the loss and modification of wetlands and riparian habitats. Of the 34 known (including historical) Canadian subpopulations, nine have been extirpated or are likely extirpated (Table 1). This translates to a 26% decline in the total number of known Canadian subpopulations over the past century. Three subpopulations appear to have been lost within the last 30 years or approximately three generations (11% inferred decline) (Table 1). At the same time, Giant Helleborine is often described as locally abundant and very persistent, flourishing for decades in suitable habitats (NatureServe 2014). Within Canada, numerous subpopulations are known to have persisted since at least the late 1800s or early 1900s when first recorded, attesting to their vigour and longevity. All extant subpopulations with at least 100 stems or more (18 of 23 subpopulations) currently are thought to possess good to excellent estimated viability (BC Conservation Data Centre 2014a).

Four subpopulations (Radium Hot Springs, Lower Arrow Lake, Duncan Lake, and Vernon) appear to have been extirpated as a result of flooding due to dams, drainage alteration for hot springs development, or wetland drainage for housing development. Another three subpopulations (Enderby, Osoyoos, and Sicamous) are presumed extirpated as Giant Helleborine has not been relocated in more than 50 years (Figure 3, Table 1).

The status of two historical subpopulations (Naramata and Celista) is unknown; precise locality information for these sites is unavailable and they have not been surveyed in more than 20 years (Figure 3, orange dots). Recent searches at Kearns Creek (in 2009 and 2010) have not yielded any plants and this subpopulation is likely extirpated (BC Ministry of Environment 2013; Figure 3, southern red dot). A subpopulation first reported near Peachland in 2010 has not been observed again in recent years and is also likely extirpated (Symonds 2013; Figure 3, northern red dot). There is anecdotal evidence to suggest that the Kootenay Lake subpopulations (Pilot Bay and Holiday Creek) have been decreasing in abundance since they were first observed in the 1990s (Hulland pers. comm. 2013). The Okanagan Falls subpopulation is also in a downward trend, having declined from “>200 stems” in 1987 to <30 stems in 2013.

All but two of the 13 subpopulations reported as extant by White and Douglas (1998) have updated observations at least as recent as 2004, and most as recent as 2010. Subpopulations at Kearns Creek and Mahoney Lake, which were considered separate sites in the 1998 report, are apparently based on the same historical observation (COSEWIC 2013). The subpopulation at Cultus Lake (EO #28), first reported in 1926, was not included in the 1998 Status Report but was last confirmed in 2004. The Columbia Lake site was also not mentioned in the 1998 update status report, even though the first observation was in 1978. This subpopulation was reconfirmed in 2013 (BC Ministry of Environment 2013). The Ainsworth Hot Springs subpopulation had not been reported since the 1950s and was presumed extirpated (BC Ministry of Environment 2013), but this site was reconfirmed as extant during the 2014 surveys.

Since the last Status Report update (White and Douglas 1998), increased search effort has discovered 12 additional subpopulations (BC Conservation Data Centre 2014a). Most of these are in the Columbia River drainage (Okanagan and Shuswap regions), with the remainder in the lower Fraser Valley. The current total of 23 extant subpopulations represents a 77% increase over the 13 reported by White and Douglas (1998). Meanwhile, over the last 10 years, there has been one confirmed extirpation (Vernon) and two possible extirpations (Kearns Creek and Peachland Creek). Aside from the subpopulation at Okanagan Falls, which is presently very small and declining, no other subpopulations appear to be at imminent risk of extirpation. Given the recent additions to the range, it is possible that further targeted searches in southern BC will continue to yield additional subpopulations and sites.

While the data imply an ongoing decline in the total number of mature ramets (i.e., flowering stems), it is the historically smaller subpopulations (<500 stems) that have shown the most recent susceptibility to large proportional declines and/or extirpation; larger subpopulations appear generally stable. Over the last 10 years the number of mature ramets lost is inferred to be <1000, or a very small fraction of the standing population. Consequently, the inferred rate of decline in the total population size over this period is relatively small, likely less than 2%. A similar rate of decline is projected for the next 10 years, assuming current conditions do not change.

Rescue Effect

With its wind-dispersed seeds and ability to colonize early successional habitat, Giant Helleborine exhibits characteristics of a pioneer species. As indicated by its disjunct, fragmented distribution, occasional long-range dispersal events do evidently occur. However, successful dispersal events appear to be relatively uncommon. Given the characteristically large separation distances between subpopulations, the likelihood of additional migrants from the same or related founder subpopulation is very slight (Thornhill 1996).

The nearest known non-Canadian occurrence (within the last 100 years) is 50 km south of the Canada-US border in the town of Colville, Washington State (Consortium of Pacific Northwest Herbaria 2014).

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Threats and Limiting Factors

Current data suggest that the majority of Giant Helleborine subpopulations in Canada are not facing any severe, imminent threats. Furthermore, the large separation distance between most subpopulations greatly limits the likelihood of any single event affecting multiple subpopulations simultaneously. The recent threats assessment rates the province-wide threat impact as “Negligible”; however, a number of threats have been identified, and the combined impact is expected to cause an overall decline that may exceed 1% in the Canadian population (also see Fluctuations and Trends). As such the assigned impact is “Low” (Appendix 1).

Where potential risks have been identified, the most serious plausible threats are from (a) droughts that lower the water table or otherwise alter the hydrological regime, (b) habitat loss associated with residential and commercial development, and (c) recreation-related disturbances such as trampling (Table 1).

A number of other plausible site-specific threats have also been identified (Table 1; BC Ministry of Environment 2013; BC Conservation Data Centre 2014b), including: livestock grazing, tufa mining, orchid harvesting, forestry activities, utility corridor maintenance, and road pollution (e.g., from herbicides, salting, and highway runoff). However, there is a higher level of uncertainty around the severity and imminence of these threat factors. Consequently, they tend to fall under the category of “threats where the imminence and harm are both hypothetical but possible” (COSEWIC 2011). In keeping with COSEWIC guidelines, these possible but hypothetical threats are not described further in this status report. Additional information on these factors as they pertain to Giant Helleborine is provided in the provincial Management Plan (BC Ministry of Environment 2013).

Only the most serious plausible threats are discussed below. These are listed under their corresponding IUCN threats classification scheme headings (IUCN 2014b).

IUCN Threat 11. Climate Change & Severe Weather

11.2 Droughts

The species depends on water, often at the edge of a water body, and may be affected by drought-related changes to hydrology or water levels. All sites likely have some potential to be impacted, thus the threat scope is rated as pervasive. The severity is likely variable depending on the site and may be slight to serious but is unknown.

IUCN Threat 1. Residential & Commercial Development

1.1 Housing & urban areas

Most known Giant Helleborine sites are in remote localities or protected areas where little immediate threat exists from land development. However, one site (Vernon) has recently been extirpated as a result of residential development. Residential construction has been identified as a likely, but not necessarily imminent, threat at two other sites situated on private property (Fairmont Hot Springs and Cape Horn). The local severity of this threat is rated as serious. However, given the relatively few localities where the threat applies, the present and future level of impact to the overall Canadian population is rated as low.

1.3 Tourism & recreation areas

Commercial recreational development of hot springs, mineral springs, or lakeshores has resulted in past habitat loss for this species and likely continues to harm plants indirectly, via water use resulting in changes to the hydrological regime. One Giant Helleborine subpopulation (Radium) has been extirpated due to development of hot springs. Further development of existing resort areas poses a potential, though not imminent, threat at two other commercial hot springs (Fairmont and Ainsworth). The local severity of this threat is rated as serious, while the present and future level of impact to the overall Canadian population is rated as negligible.

IUCN Threat 5. Biological Resource Use

5.2 Collecting terrestrial plants

Giant Helleborine is targeted in the wild by herb gatherers, with the best known population at Mara Meadows, which is likely too small to support any level of ongoing harvest of plants (Fraser pers. comm. 2015). In Montana, the species is on a watchlist developed for herbalists in order to conserve wild populations (Lee 2015). The “Reasons For Designation” as Special Concern by COSEWIC identified the potential risks from orchid collectors; however, this threat is currently considered negligible.

IUCN Threat 6. Human Intrusion & Disturbance

6.1 Recreational activities

Trampling by hikers and pedestrians is suspected of causing soil compaction, erosion, and stem breakage at some sites, which reduces reproductive success and may also impact plant survival. Trail erosion and trampling by hikers, and trampling by boaters landing near lakeshore subpopulations, has been reported at Pilot Bay Provincial Park and Cape Horn. At Peachland Creek, pedestrian trampling associated with salmon viewing may have contributed to the recent decline (and possible extirpation) at this small site, although this is unconfirmed. The Peachland site also appears to have been impacted by bridge construction in 2012, with silt fencing still present in the riparian area (Symonds 2013; Figure 7). Some pedestrian trampling also occurs at Fairmont Hot Springs, where many people come annually to bathe at the pools. Mud-bogging with off-road vehicles has occurred in the past at the Upper Violet Creek (Bilbo’s Bog) site but is presently being mitigated through summer use management measures and the erection of physical barriers (BC Ministry of Environment 2013). The local severity of the threat from recreational activities is rated as medium. The present and future level of impact to the overall Canadian population is rated as negligible.

Figure 7. Former occupied habitat along Peachland Creek, with recently installed silt fencing. Photo by J. Symonds, with permission.
Image of Giant Helleborine habitat along a river bank
Long description for Figure 7

Photo of habitat formerly occupied by the Giant Helleborine along Peachland Creek. The photo shows silt fencing in the riparian area.

IUCN Threat 7. Natural System Modifications

7.2. Dams & water management/use

Flooding associated with dam construction has extirpated two historical occurrences but is not expected to impact any known sites in the next 10 years (BC Ministry of Environment 2013). Dam control of water levels in Kootenay Lake, which since the 1950s has led to a reduction in the height of annual flooding along the shoreline, may be acting to reduce Giant Helleborine abundance at Pilot Bay and Cape Horn, both by altering the available water for Giant Helleborine and by facilitating forest tree incursions onto riparian habitat. At Holiday Creek, a proportion of the subpopulation has been lost in the last 10 years due to habitat drying resulting from upslope water diversions on private lands. Habitat drying may also have contributed to the possible extirpation of the Kearns Creek site, although this has not been confirmed.

Water extraction and management for commercial and private hot spring operations pose an ongoing potential threat to subpopulations at Ainsworth Hot Springs and Fairmont Hot Springs (see Threat 1.3, above). At Fairmont, alterations to thermal water flows over the past few decades (either due to natural or anthropogenic processes) have resulted in documented local extirpations of the associated hot spring-dependent and SARA-listed species Southern Maiden-hair Fern (Adiantum capillus-veneris; Environment Canada 2013). Giant Helleborine has also been reduced from its historical abundance levels at these localities (Brunton 1984). Nevertheless, stable subpopulations of Giant Helleborine have also persisted at these commercial sites, presumably for many decades, under the current water use regimes (Figure 5; Table 1). While the local severity of this threat is rated as serious, further impacts are only likely if present water use patterns change in some substantive way. The present and future level of impact to the overall Canadian population from dams and water management/use is rated as negligible.

IUCN Threat 8. Invasive & Other Problematic Species & Genes

8.1. Invasive non-native/alien species

Invasive alien plants have been reported at several sites, albeit effects of co-occurring alien invasive species are generally unknown. For example, Purple Loosestrife (Lythrum salicaria) has become established at Skaha Lake Southwest. This highly competitive species is capable of taking over shallow waters of lakeshores and ditches and forming monocultures, but at this point appears to have little impact on Giant Helleborine (BC Ministry of Environment 2013). At Holiday Creek, the invasive shrub Himalayan Blackberry (Rubus armeniacus) has become established (along with native shrubs), but does not yet occur at density levels sufficient to significantly impact the very large Giant Helleborine subpopulation there (Miller pers. obs. 2014).

Reed Canary Grass (Phalaris arundinacea) dominates the herbaceous layer at the Camp Owaissii (Okanagan Lake west) site and may be competing with Giant Helleborine here (Symonds 2013). Invasive species are well established at Okanagan Falls and appear to pose the greatest threat to this small site (Symonds 2013). Several invasive plants were recorded near the Columbia Lake site in 2013 (BC Ministry of Environment 2013), including: Oxeye Daisy (Leucanthemum vulgare), knapweed (Centaurea sp.), thistle (Cirsium sp.), and dandelions (Taraxacum sp.), but no direct impacts were noted. The local severity of the threat from alien invasive species is rated as medium. The present and future level of impact to the overall Canadian population is rated as negligible.

8.2. Problematic native species

Infill by upland forest trees and shrubs such as snowbrush (Ceanothus spp.) and Saskatoon (Amelanchier alnifolia) is creating shading for Giant Helleborine as well as possible competition for resources at the Holiday Creek site (Table 1; Figure 8). Forest encroachment onto riparian habitats at Pilot Bay and Cape Horn (a direct consequence of the lower lake levels experienced since the 1950s) also appears to be negatively impacting orchid abundance at Pilot Bay and Cape Horn (Hulland pers. comm. 2014). Trampling of Giant Helleborine by Bighorn Sheep (Ovis canadensis) has been noted at Columbia Lake (BC Ministry of Environment 2013), although with unknown long-term effect. Evident signs of deer browse have been observed at some sites (e.g., McTaggart-Cowan WMA and Hopyard Hill; Figure 9). Deer appear to preferentially target developing seed capsules, which can result in substantial losses to the standing seed crop (see “Interspecific Interactions,” above). The local severity of the threat from problematic native species is rated as medium. The present and future level of impact to the overall Canadian population is rated as negligible.

Figure 8. Giant Helleborine (foreground) below encroaching native and non-native shrubs along the highway embankment near Boswell, 2013. Photo by M. Miller, with permission.
Image of Giant Helleborine habitat
Long description for Figure 8

Photo of Giant Helleborine below encroaching native and non-native shrubs along the highway embankment near Boswell (Holiday Creek subpopulation).

Figure 9. Stem of Giant Helleborine showing evidence of deer browse at McTaggart-Cowan WMA, 2014. The upper stem with inflorescence and developing fruit capsules has been removed. Photo by M. Miller, with permission.
close up image of Giant Helleborine
Long description for Figure 9

Photo of a Giant Helleborine stem with evidence of deer browse at the McTaggart-Cowan/nsek'tniw't Wildlife Management Area. The upper stem with the inflorescence and developing fruit capsules has been removed.

Number of Locations

Subpopulations tend to be small in area (<1 ha), patchily distributed, and widely disjunct from one another, and they occur in a variety of jurisdiction types (private lands, provincial parks, ecological reserves, provincial protected areas, provincial crown land, and federal crown land) and ecosystems. Furthermore, most of the specific threats (e.g., shrub encroachment, water manipulation) tend to be idiosyncratic (peculiar to the site) and localized in nature. For this reason, each subpopulation is here considered to equate to a distinct location (sensu IUCN 2014a), with the following exception. The habitat supporting the Holiday Creek subpopulation spans a highway right of way (ROW), a power line ROW, and a parcel of private property, each of which is associated with different threat factors. This subpopulation is therefore counted as three separate locations (Table 1).

In all, there are 25 identified “locations” (29 locations if the historical and likely extirpated subpopulations prove to be extant; Table 1).

Applying the same location criteria retrospectively to the site data of White and Douglas (1998) produces an estimate of 14 known locations in 1998. The number of known locations has thus slightly less than doubled in the last 16 years--a comparable increase to that noted above for subpopulations. As for subpopulations, this increase reflects recent search effort rather than range expansion or recovery. The number of sites is likely to increase over time with additional survey effort, especially as surveys begin to focus on areas away from the populated valleys where to date most known sites occur. Another doubling of locations on public land is not unexpected, although the final total is unlikely to exceed 100.

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Protection, Status and Ranks

Legal Protection and Status

Giant Helleborine, as are all orchids, is protected under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES 2014).

COSEWIC assessed this species as Not at Risk in November 2015. Giant Helleborine is listed on the Species at Risk Act(SARA) Schedule 3 as Special Concern. However, species of Schedule 3 are not afforded any protection under SARA, and no federal management plan is in place. The species is not protected under provincial species at risk legislation, nor does it receive specific protection through any federal or state laws in the U.S.

A provincial Management Plan is in place for Giant Helleborine in British Columbia (BC Ministry of Environment 2013). Actions implemented under this Management Plan include monitoring of trends (in progress); and habitat protection and private land stewardship (also in progress). The BC Ministry of Forests, Lands and Natural Resource Operations; Ministry of Environment Parks Staff; consultants; and volunteers have monitored populations in 2009, 2010, 2011 (Dyer and Bunge 2012) and 2013 (Symonds 2013). Landowner contact at Fairmont Hot Springs and Okanagan Lake west is ongoing.

Non-Legal Status and Ranks

Globally, Giant Helleborine is ranked by NatureServe (2014) as G4 (Apparently Secure). It is ranked N3 (Vulnerable) in Canada and N3N4 (Vulnerable to Apparently Secure) in the United States.

At the provincial level, it is ranked S3 (Vulnerable) in BC and has a Conservation Framework (CF, approach for guiding conservation actions) Priority rank of 2 (second highest priority, BC Conservation Data Centre 2014a). In the U.S. it is ranked Critically Imperiled (S1) in South Dakota and Wyoming, Critically Imperiled to Imperiled (S1S2) in Oklahoma, Possibly Imperiled (S2?) in New Mexico, Imperiled to Vulnerable (S2S3) in Colorado, Vulnerable (S3) in Idaho, Montana, Texas, and Washington, and Vulnerable to Apparently Secure (S3S4) in Arizona and Utah. It is Not Ranked (SNR) for California and Oregon (NatureServe 2014), although apparently secure in California (Coleman 1988; Hickman 1993; Rocchio et al. 2006).

Giant Helleborine has not been assessed for inclusion on the IUCN Red List (IUCN 2014c).

Habitat Protection and Ownership

Eight Giant Helleborine subpopulations are within provincial parks, protected areas, or ecological reserves and are afforded some measures of protection through the legal provisions of the B.C. Park Act and the Ecological Reserve Act. One location is in a Wildlife Management Area and is afforded some measure of protection through provisions of the Wildlife Act and conservation lands managed by the Province of BC. One location is within a federal park, which is afforded some measure of protection through provisions of the Canada National Parks Act.

In all, 10 of 25 confirmed locations (or 40%) receive some form of formal habitat protection. Another eight locations (32%) are on provincial or federal crown lands. The remaining seven locations (28%) occur either on private lands or on lands of uncertain ownership status. In terms of total plant numbers, the great majority of ramets (~80%) are located within areas that are afforded some measure of protection (Table 1).

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Acknowledgements and Authorities Contacted

Numerous individuals have participated in monitoring and inventory for this species over the years, and their contributions are gratefully acknowledged. Those contributing field time in 2013 and 2014 include: Ted Antifeau, Craig Browne, Sara Bunge, Orville Dyer, Mike Gall, Jamie Leathem, Bryan Kelly-McArthur, Mike Miller, Susan Hulland, Verne Smythe, Robert Stewart, Josie Symonds, Mark Weston, and Brett Yeates. Additional data and advice were provided by Bruce Bennett, Brenda Costanzo, and Jenifer Penny. The in-kind support of the B.C. Ministry of Environment (in the form of person-days) is gratefully acknowledged. Special thanks to Susan Hulland and Bryan Kelly-McArthur, who generously volunteered their time to accompany the report writer on field trips and assist with plant counts.

Authorities Contacted

Bruce Bennett, Co-Chair Vascular Plants Specialist Subcommittee, COSEWIC, Whitehorse, YT

Rhonda Milliken, Head Population Assessment, Canadian Wildlife Service, Delta, BC

Danielle Backman, Ecologist Team Leader, Mount Revelstoke and Glacier National Parks, Revelstoke, BC

Bryan Chruszcz, Fire and Vegetation Ecologist, Mount Revelstoke and Glacier National Parks, Revelstoke, BC

Dave Fraser, Unit Head, Species Focused Conservation, Conservation Science Section, BC Ministry of Environment, Victoria, BC

Jenifer Penny, Program Botanist, BC Conservation Data Centre, Victoria, BC

Brenda Costanzo, Senior Vegetation Specialist, Conservation Science Section, BC Ministry of Environment, Victoria, BC

Neil Jones, Scientific Project Officer & ATK Coordinator, COSEWIC Secretariat, Canadian Wildlife Service, Gatineau, QC

Jenny Wu, Scientific Project Officer, COSEWIC Secretariat, Canadian Wildlife Service, Gatineau, QC

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Information Sources

Arditti, J., J.D. Michaud, A.P. Olivia, and P. Allison. 1981. Seed germination of North American orchids, I. Native California and related species of Calypso, Epipactis, Goodyera, Piperia, and Platanthera. Botanical Gazette 142(4):442-453.

Argue, C.L. 2012. The Pollination Biology of North American Orchids: Volume 2: North of Florida and Mexico. DOI 10.10007/978-1-4614-0622-8_3, Springer Science+Business Media, LLC. New York, NY.

B.C. Conservation Data Centre. 2014a. BC Species and Ecosystems Explorer. B.C. Ministry of Environment, Victoria, B.C. [accessed June 4, 2014].

B.C. Conservation Data Centre. 2014b. Species summary: Epipactis gigantea. B.C. Ministry of Environment, Victoria, B.C.. [accessed March 10, 2014].

B.C. Ministry of Environment. 2013. Management Plan for Giant Helleborine (Epipactis gigantea) in British Columbia. B.C. Ministry of Environment, Victoria, BC. 17pp.

Brown, P.M., and G.W. Argus. Epipactis. 2002. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford. Vol. 26, p. 585.

Brunton, D.F. 1984. Status report on the Giant Helleborine, Epipactis gigantea, in Canada. Unpublished report submitted to the Committee on the Status of Endangered Wildlife in Canada. Canadian Wildlife Service, Ottawa, ON. 32 pp.

Brunton, D.F. 1986. Status of the Giant Helleborine, Epipactis gigantea (Orchidaceae), in Canada. Canadian Field-Naturalist 100:414–417.

CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). 2014. CITES Species+ Database. [accessed 26 October 2014].

Coleman, R.A. 1988. The Epipactis of California. Fremontia 16:24-27.

Coleman, R.A. 2002. The Wild Orchids of Arizona and New Mexico. Cornell University Press, Ithaca, NY. 272 pp.

Consortium of Pacific Northwest Herbaria. 2014. Specimen data for Epipactis gigantea. University of Washington Herbarium, The Burke Museum of Natural History and Culture. Seattle, WA. [accessed 10 October 2014].

COSEWIC(Committee on the Status of Endangered Wildlife in Canada). 2011. Appendix F1. Instructions for the Preparation of COSEWIC Status Reports. Committee on the Status of Endangered Wildlife in Canada. [accessed 10 October 2014].

COSEWIC (Committee on the Status of Endangered Wildlife in Canada). 2013. COSEWIC draft unpublished 2013 Status Appraisal Summary for Giant Helleborine, Epipactis gigantea in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 14 pp.

Cronquist, A., A.H. Holmgren, N.H. Holmgren, J.L. Reveal, and P.K. Holmgren. 1977. Intermountain Flora Vascular Plants of the Intermountain West, USA: Vol. 6. New York Botanical Garden, Bronx, NY.

Dickoré, W.B. 1995. Systematische Revision und chorologische Analyse der Monocotyledoneae des Karakorum (Zentralasien, West-Tibit). Flora Karakorumensis 1, Angiospermae, Monocotyledoneae. Stapfia 39:1-298.

Douglas, G.W., D. Meidinger, and J. Pojar, eds. 2001. Illustrated flora of British Columbia, Vol. 7, Monocotyledons (Orchidaceae through Zosteraceae). BC Min. Sustainable Resour. Manage. and BC Min. For., Victoria, BC. 379 pp.

Dressler, R.L. 1981. The Orchids: Natural history and classification. Harvard University Press, Cambridge, MA. 344 pp.

Dyer, O., and S. Bunge. 2012. Giant Helleborine (Epipactis gigantea) inventory and monitoring in the Southern Interior of British Columbia 2009 to 2012. B.C. Min. Forests, Lands and Natural Resource Operations, and Ministry of Environment, Parks Branch, Penticton, BC. Draft internal working report.

Edrom Nurseries. 2014. Epipactis gigantea. [accessed 10 October 2014].

Enns, A., pers. comm. 2014. Email correspondence with Bruce Bennett, 28 October 2014. National Data Manager, NatureServe Canada. Vancouver, BC.

Environment Canada. 2013. Recovery Strategy for the Southern Maidenhair Fern (Adiantum capillus-veneris) in Canada. Species at Risk Act Recovery Strategy Series. Environment Canada, 13 pp. + Appendix.

Fraser, R., pers. comm. 2015. Phone conversation to David Fraser Feb 2015. Horticultural specialist, Victoria, BC.

Freeman, C. pers. comm. 2014. Email correspondence with Bruce Bennett, 28 October 2014. Senior Scientist, University of Kansas, Lawrence, KS.

Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp.

Hornbeck, J.H., D. Reyher, C.H. Sieg, and R.W. Crook. 2003. Conservation Assessment for Southern Maidenhair Fern and Stream Orchid in the Black Hills National Forest, South Dakota and Wyoming. United States Department of Agriculture, Forest Service, Rocky Mountain Region, Black Hills National Forest. Custer, SD. [accessed October 2014].

Hulland, S., pers. comm. 2013. Verbal communication with M.T. Miller, 22 July 2013. Resident, Crawford Bay, BC.

Hulland, S., pers. comm. 2014. Email communication to M.T. Miller, 8 October 2014. Resident, Crawford Bay, BC.

IUCN (International Union for Conservation of Nature and Natural Resources). 2014a. Guidelines for Using the IUCN Red List Categories and Criteria. Version 11. Prepared by the Standards and Petitions Subcommittee.

IUCN (International Union for Conservation of Nature and Natural Resources). 2014b. The IUCN Red List of Threatened Species. Threats Classification Scheme (Version 3.2). [accessed October 2014].

IUCN (International Union for Conservation of Nature and Natural Resources). 2014c. The IUCN Red List of Threatened Species. [accessed 26 October 2014].

Kane, C.W. 2015. Epipactis gigantea |Stream Orchid | Medicinal Uses. [accessed 18 February 2015].

Lee, B. 2015. Montana Herbalist. Website: http://www.montanaherbalist.com/at-risk-herbal-alert.html [accessed 18 February 2015].

Levine, J. 2000. Complex interactions in a streamside plant community. Ecology 81:3431-3444.
Lomer, F., pers. comm. 2015. Email communication to M.T. Miller, 25 March 2015. Botanist, Vancouver, BC.

Luer, C.A. 1975. The Native Orchids of the United States and Canada, Excluding Florida. New York Botanical Garden, New York, NY. 362 pp.

Mantas, M. 1993. Ecology and Reproductive Biology of Epipactis gigantea Dougl. (Orchidaceae) in Northwestern Montana. M.S. Thesis, University of Idaho.

Mancuso, M. 1991. Field Investigation of Epipactis gigantea (giant helleborine), a Region 4 Sensitive Species, on the Payette National Forest. Idaho Department of Fish and Game, Boise, ID.

NatureServe. 2014. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. [accessed: March 25, 2014].

Rocchio, J., M. March, and D.G. Anderson. 2006. Epipactis gigantea Dougl. ex Hook. (stream orchid): a technical conservation assessment. [Online]. USDA Forest Service, Rocky Mountain Region. [accessed Oct. 1 2014].

Schassberger, L.A. 1988. Status review of Epipactis gigantea, USDA Forest Service, Region 1, Flathead National Forest. Unpublished report. Montana Natural Heritage Program, Helena, MT. 42 pp.

Steinauer, G., pers. comm. 2014. Email correspondence with Bruce Bennett. 28 October 2014. Botanist/Ecologist, Nebraska Natural Heritage Program, Lincoln, NE.

Symonds, J. 2013. Giant Helleborine (Epipactis gigantea) Inventory and Monitoring Summary Report (2013). Unpubl. Report for BC Ministry of Forests, Lands and Natural Resource Operations, Ecosystems Section, Thompson Okanagan Region (Penticton). 12 pp.

The Plant List (2010). Version 1. [accessed 29 August 2015].

Thornhill, A.D. 1996. Species and population-level patterns of genetic variation in Epipactis gigantea (Orchidaceae), with examination of local genetic and clonal structure in riparian and bog populations inferred from allozyme analysis. Univ. California, Irvine, Calif. Dissertation. 73 pp.

Treher, A., pers. comm. 2014. Email correspondence with Bruce Bennett, 28 October 2014. Research Botanist, NatureServe, Arlington, VA.

Vij, S.P., P. Kaur, and R.K. Bhamura. 1999. Embryological studies in Epipactis gigantea(Orchidaceae). Lindleyana 14:160-167.

White, D.J., and G.W. Douglas. 1998. Update COSEWIC status report on Giant Helleborine, Epipactis gigantea, in Canada. Unpublished report submitted to the Committee on the Status of Endangered Wildlife in Canada. Canadian Wildlife Service, Ottawa, ON. 4 pp.

Wu, J., pers. comm. 2014. Email correspondence to M.T. Miller, 21 October 2014. Scientific Project Officer, COSEWIC Secretariat, Canadian Wildlife Service, Environment Canada, Gatineau, QC.

Zapotoczny, W. 2015. Common native medicinal plants of California.

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Biographical Summary of Report Writers

Dr. Michael T. Miller has a Ph.D. in Biology from University of Victoria (2004). He has worked on the demography, inventory, and recovery of rare species for approximately 15 years, and has authored and co-authored numerous COSEWIC status reports.

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Collections Examined

Collections at the University of British Columbia (UBC), Royal British Columbia Museum (V), University of Washington (WTU), and University of Idaho (ID) were consulted through the online database of the Consortium of Pacific Northwest Herbaria (2014).

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Appendix 1. Threats Assessment Worksheet.

Threats Assessment Worksheet

Species or Ecosystem Scientific Name:
Giant helleborine, Epipactis gigantea
Element ID
-
Elcode
-
Date:
23/03/2015
Assessor(s):
Bruce Bennett, Dave Fraser, Mike Miller (report writer), Stephanie Pellerin, Karen Timm
References:
Original draft spreadsheet proved by BC provincial staff
Overall Threat Impact Calculation Help:
Threat ImpactThreat Impact (descriptions)Level 1 Threat Impact Counts:
high range
Level 1 Threat Impact Counts:
low range
AVery High00
BHigh00
CMedium00
DLow00
-Calculated Overall Threat Impact:--
Assigned Overall Threat Impact:
D = Low
Impact Adjustment Reasons:
-
Overall Threat Comments
The calculated overall threat impact was “Negligible”; however, a number of threats have been identified, and the combined impact is expected to cause an overall decline that may exceed 1% in the Canadian population. As such the assigned impact is “Low”.
Threats Assessment Worksheet Table.
#ThreatImpact
(calculated)
Scope
(next
10 Yrs)
Severity
(10 Yrs
or
3 Gen.)
TimingComments
1Residential and commercial developmentNegligibleNegligible (<1%)Serious (31-70%)Moderate (Possibly in the short term, < 10 yrs) 
1.1Housing and urban areasNegligibleNegligible (<1%)Serious (31-70%)Moderate (Possibly in the short term, < 10 yrs)22 extant sites, 7 on or partly on private land, 1 (5%), Fairmont Hot Springs, has potential for ongoing development that may include residential and tourism-oriented buildings. Cape Horn has been identified as a potential cottage development site (pers. comm. to Mike Miller) but no development expected on other sites in next 10 years. Severity could be extreme but likely will be mitigated by Water Act regulations affecting developing directly in water or affecting water flow. Overall scope is below 1% because the number of stems at impacted sites is small.
1.2Commercial and industrial areas    No proposed sites are known. See above.
1.3Tourism and recreation areasNegligibleNegligible (<1%)Serious (31-70%)Moderate (Possibly in the short term, < 10 yrs)22 extant sites, 7 on or partly on private land. 1 site (5%), Fairmont Hot Springs, has potential for ongoing development. No development expected on other sites in next 10 years. Severity could be extreme. Overall scope is below 1% because the number of stems at impacted sites is small.
2Agriculture and aquacultureUnknownSmall  (1-10%)UnknownHigh (Continuing) 
2.3Livestock farming and ranchingUnknownSmall  (1-10%)UnknownHigh (Continuing)Range use occurs at Okanagan Falls, Mabel Lake north end, Park Rill (3/22 = 14% of extant sites). Impacts of trampling likely vary. No documentation was found to quantify impact severity. Ongoing and fairly intensive cattle use at Park Rill hasn’t extirpated the population. Flowering stems may be broken from trampling, reducing reproduction but likely won’t kill the plant or cause a population level reduction. Grazing may also compact soil and affect hydrology but little information. Severity is tentatively estimated as unknown. Haying may occur at part of the Okanagan Falls site; the impact is unknown. Livestock may be the cause of the extirpation at Kearns Creek.
3Energy production and miningNegligibleNegligible (<1%)UnknownUnknown 
3.2Mining and quarryingNegligibleNegligible (<1%)UnknownUnknownTufa mining has been mentioned for lands adjacent to Columbia Lake in the Kootenays but it is in an ecological reserve surrounded by a wildlife management area so seems unlikely. It is considered unknown at this point.
4Transportation and service corridorsNegligibleSmall  (1-10%)Negligible (<1%)High (Continuing) 
4.1Roads and railroadsNegligibleSmall  (1-10%)Negligible (<1%)High (Continuing)Road herbicide runoff or maintenance activities (e.g., mowing) have been identified as potential impacts for Revelstoke, Ainsworth, Holiday Creek, Tappen, and potentially Columbia Lake (5/22 = 23% of known subpopulations). Scope is considered to be small based on the impact to the Canadian population. The subpopulations appear stable using current maintenance practices (Mike Miller pers. comm.) and the overall impact to the Canadian population appears negligible.
4.2Utility and service linesNegligibleNegligible (<1%)Negligible (<1%)High (Continuing)The utility corridor at Holiday Creek has a potential impact but is considered negligible: likely should contact the corridor operator to implement stewardship. Columbia Lake has a power line corridor and ongoing management might impact the plants. These include tree falling and piling - they would be included in other categories (e.g., 5.3 logging) but are considered here and not considered to be substantial.
5Biological resource useNegligibleNegligible (<1%)Negligible (<1%)High (Continuing) 
5.1Hunting and collecting terrestrial animals     
5.2Gathering terrestrial plantsNegligibleNegligible (<1%)Negligible (<1%)High (Continuing)Collection for medicinal uses is an ongoing threat, particularly at the Mara Meadows site. Orchid collecting has been identified as a potential threat but no evidence is available to suggest it is a concern for this species. At this point it is considered negligible
5.3Logging and wood harvestingNegligibleNegligible (<1%)UnknownLow (Possibly in the long term, >10 yrs)Upslope logging, which could result in hydrological changes to lakeshore habitat, has been indicated as a potential threat to some Pilot Bay subpopulations (pers. comm. to Mike Miller), but does not appear imminent.
6Human intrusions and disturbanceNegligibleNegligible (<1%)Negligible (<1%)High (Continuing) 
6.1Recreational activitiesNegligibleNegligible (<1%)Negligible (<1%)High (Continuing)Helleborine occurs in several parks so recreation has been identified as a potential threat. Mud bogging was a problem at Bilbo’s Bog (Upper Violet Creek PP) but barriers have eliminated this activity at this site. Trampling appears to be fairly limited and irregular but has been reported at Pilot Bay and Fairmont (2/22 sites = 9%). Severity has not been quantified. It seems likely that breakage of flowering stems could result in reduced reproduction but is unlikely to kill the plant. Severity is estimated at negligible. Trampling has been mentioned at Columbia Lake as well but it is not a formal development and impacts are not clear. Although 3-4 sites are potentially impacted, <1% of plants overall would likely be affected.
7Natural system modificationsNegligibleNegligible (<1%)UnknownModerate (Possibly in the short term, < 10 yrs) 
7.1Fire and fire suppression    not expected, not likely
7.2Dams and water management/useNegligibleNegligible (<1%)UnknownModerate (Possibly in the short term, < 10 yrs)Dams and water management have extirpated sites in the past. New dams are not expected in the next 10 years. The damming of Kootenay Lake for flood control (in the 1930s) has resulted in forest encroachment onto lakeshore habitat at Pilot Bay (pers. comm. to M. Miller). Ongoing water management may be an issue at Fairmont Hot Springs (1/22 sites = 5%). A range of severity from serious to moderate might be expected.
8Invasive and other problematic species and genesNegligibleNegligible (<1%)Slight  (1-10%)High (Continuing) 
8.1Invasive non-native/alien speciesNegligibleNegligible (<1%)Slight  (1-10%)High (Continuing)Himalayan Blackberry occurs at the Holiday Creek site and may pose a threat. Purple Loosestrife occurs at the Skaha Lake site, although impacts appear to be negligible. Invasive alien spp. are thought to be the primary threat to the small Okanagan Falls site. Reed Canary Grass is a dominant species at the Camp Owaissi site. Non-native thistles occur at Fairmont Hot Springs and McTaggart-Cowan WMA (6/22 = 27%). To date, however, there have been no documented extirpations or declines directly linked to invasive alien spp., and the overall impact is likely negligible.
8.2Problematic native speciesNegligibleNegligible (<1%)Negligible (<1%)High (Continuing)Potential impacts from competition with encroaching native shrubs (e.g., Red-osier Dogwood and alder at Holiday Creek, juniper at Fairmont), browsing by deer at Hopyard Hill and McTaggart-Cowan WMA, and trampling by deer and Bighorn Sheep at Columbia Lake have been identified as potential issues (5/22 sites = 23%). The severity of the impact is not quantified, although deer browse was identified as a potentially serious issue at Hopyard Hill and Mountain Slough due to the small number of plants (most observed plants were grazed). A range of severity is expected. Browse and trampling likely won’t kill the plants directly, so likely is negligible except potentially for small populations. Impacts from shrub ingrowth may be more serious, although Giant Helleborine has shown an ability to persist beneath shrub thickets at several sites.
9Pollution     
9.3Agricultural and forestry effluents    Herbicide spraying along the TransCanada Highway has occurred in the past in the vicinity of the Mt. Revelstoke site and may be an issue at Cranberry Creek (addressed in Roadside Maintenance 4.1)
10Geological events     
10.3Avalanches/landslides    A mudslide recently occurred near one site (1/22 = 5%) (Fairmont), but the Giant Helleborine habitat was not impacted (Halverson pers. comm.).
11Climate change and severe weatherNot Calculated (outside assessment timeframe)Pervasive (71-100%)UnknownLow (Possibly in the long term, >10 yrs) 
11.2DroughtsNot Calculated (outside assessment timeframe)Pervasive (71-100%)UnknownLow (Possibly in the long term, >10 yrs)The species depends on water, often at the edge of a water body, and may be affected by drought related changes to hydrology or water levels. All sites likely have some potential to be impacted. The scope applies to all sites (pervasive). The severity is likely variable depending on the site and may be slight to serious but is unknown.

Glossary

Impact
The degree to which a species is observed, inferred, or suspected to be directly or indirectly threatened in the area of interest. The impact of each threat is based on Severity and Scope rating and considers only present and future threats. Threat impact reflects a reduction of a species population or decline/degradation of the area of an ecosystem. The median rate of population reduction or area decline for each combination of scope and severity corresponds to the following classes of threat impact: Very High (75% declines), High (40%), Medium (15%), and Low (3%). Unknown: used when impact cannot be determined (e.g., if values for either scope or severity are unknown); Not Calculated: impact not calculated as threat is outside the assessment timeframe (e.g., timing is insignificant/negligible or low as threat is only considered to be in the past); Negligible: when scope or severity is negligible; Not a Threat: when severity is scored as neutral or potential benefit.
Scope
Proportion of the species that can reasonably be expected to be affected by the threat within 10 years. Usually measured as a proportion of the species’ population in the area of interest. (Pervasive = 71–100%; Large = 31–70%; Restricted = 11–30%; Small = 1–10%; Negligible < 1%).
Severity
Within the scope, the level of damage to the species from the threat that can reasonably be expected to be affected by the threat within a 10-year or three-generation timeframe. Usually measured as the degree of reduction of the species’ population. (Extreme = 71–100%; Serious = 31–70%; Moderate = 11–30%; Slight = 1–10%; Negligible < 1%; Neutral or Potential Benefit > 0%).
Timing
High = continuing; Moderate = only in the future (could happen in the short term [< 10 years or 3 generations]) or now suspended (could come back in the short term); Low = only in the future (could happen in the long term) or now suspended (could come back in the long term); Insignificant/Negligible = only in the past and unlikely to return, or no direct effect but limiting.

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Appendix 2. Threat classification table for Giant Helleborine in BC. From BC Ministry of Environment (2013).
Threat #Threat descriptionImpactaScopebSeveritycTimingd 
1Residential & commercial developmentLowSmallSeriousHigh
1.1 Housing & urban areasLowSmallSeriousHigh
1.3 Tourism & recreation areasLowSmallSeriousHigh
2Agriculture & aquacultureUnknownRestrictedUnknownHigh
2.3Livestock farming & ranchingUnknownRestrictedUnknownHigh
3Energy Production & MiningNegligibleNegligibleNot ScoredLow
 3.2 Mining & QuarryingNegligibleNegligibleNot ScoredLow
5Biological resource useNegligibleNegligibleNot ScoredLow
5.2 Gathering terrestrial plantsNegligibleNegligibleNot ScoredLow
6.Human intrusions & disturbanceNegligibleSmallNegligibleHigh
6.1 Recreational activitiesNegligibleSmallNegligibleHigh
7Natural system modificationsLowSmallSerious - ModerateModerate
7.2 Dams & water management/useLowSmallSerious - ModerateModerate
7.3 Other ecosystem modificationsNegligibleNegligibleNot ScoredHigh
8Invasive & other problematic species & genesLowRestrictedSlightHigh
8.1 Invasive non-native/alien speciesLowSmallSlightHigh
8.2 Problematic native speciesLowRestrictedSlightHigh
9PollutionUnknownSmallUnknownHigh
9.3 Agricultural & forestry effluentsUnknownSmallUnknownModerate
10Geological eventsUnknownSmallUnknownModerate
10.3 Avalanches/landslidesUnknownSmallUnknownModerate
11Climate change & severe weatherUnknownPervasiveUnknownModerate
11.2 DroughtsUnknownPervasiveUnknownModerate

a. Impact – The degree to which a species is observed, inferred, or suspected to be directly or indirectly threatened in the area of interest. The impact of each threat is based on Severity and Scope rating and considers only present and future threats. Threat impact reflects a reduction of a species population or decline/degradation of the area of an ecosystem. The median rate of population reduction or area decline for each combination of scope and severity corresponds to the following classes of threat impact: Very High (75% declines), High (40%), Medium (15%), and Low (3%). Unknown: used when impact cannot be determined (e.g., if values for either scope or severity are unknown); Not Calculated: impact not calculated as threat is outside the assessment time (e.g., timing is insignificant/negligible [past threat] or low [possible threat in long term]); Negligible: when scope or severity is negligible.

b. Scope – Proportion of the species that can reasonably be expected to be affected by the threat within 10 years. Usually measured as a proportion of the species’ population in the area of interest. (Pervasive = 71–100%; Large = 31–70%; Restricted = 11–30%; Small = 1–10%; Negligible < 1%).

c. Severity – Within the scope, the level of damage to the species from the threat that can reasonably be expected to be affected by the threat within a 10-year or 3-generation timeframe. Usually measured as the degree of reduction of the species’ population. (Extreme = 71–100%; Serious = 31– 70%; Moderate = 11–30%; Slight = 1–10%; Negligible < 1%; Neutral or Potential Benefit > 0%).

d. Timing – High = continuing; Moderate = only in the future (could happen in the short term [< 10 years or 3 generations]) or now suspended (could come back in the short term); Low = only in the future (could happen in the long term) or now suspended (could come back in the long term); Insignificant/Negligible = only in the past and unlikely to return, or no direct effect but limiting.

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