SPECIES: Scientific [common] [Giant helleborine; Stream orchid] Forest: Salmon–Challis National Forest Forest Reviewer: Brittni Brown, Rose Lehman, John Proctor Date of Review: 3 January 2018, 27 March 2018 Forest concurrence (or YES recommendation if new) for inclusion of species on list of potential SCC: (Enter Yes or No)

FOREST REVIEW RESULTS: 1. The Forest concurs or recommends the species for inclusion on the list of potential SCC: Yes _X_ No___

2. Rationale for not concurring is based on (check all that apply): Species is not native to the plan area ______Species is not known to occur in the plan area ______Species persistence in the plan area is not of substantial concern ______

FOREST REVIEW INFORMATION:

1. Is the Species Native to the Plan Area? Yes _X_ No___

If no, provide explanation and stop assessment.

2. Is the Species Known to Occur within the Planning Area? Yes_ X _ No___

If no, stop assessment. Table 1. All Known Occurrences, Years, and Frequency within the Planning Area

Year Number of Location of Observations (USFS Source of Information Observed Individuals District, Town, River, Road Intersection, HUC, etc.) 1990 9 Warm Spring Creek drains west IDFG Element Occurrence into the Salmon River at river EO Number: 9 mile 285, about 37 miles north EO_ID: 2207 of Challis.

Salmon–Cobalt Ranger District 1997 100 Loon Creek Hot Springs along IDFG Element Occurrence lower Loon Creek just upstream EO Number: 14 from the Middle Fork Salmon EO_ID: 1789 River.

Middle Fork Ranger District 1989 11 to 50 Hot Springs Creek, circa 1 mile IDFG Element Occurrence above confluence with Panther EO Number: 15 Creek, Salmon NF, Cobalt RD. EO_ID: 7914

Salmon–Cobalt Ranger District 1989 51-100 Owl Creek Hot Springs, ca 2 mi IDFG Element Occurrence ramets above confluence of Owl Creek EO Number: 16 with the Salmon River. EO_ID: 333

North Fork Ranger District 2002 150 In meadows of southernmost IDFG Element Occurrence major hot springs on Loon EO Number: 27 Creek trail, between 0.25 and 1 EO_ID: 3056 mile south of confluence of Warm Spring Creek and Loon Creek. Also at Owen Cabin Hot Springs, circa 0.1 mile south of Owen Cabin along Loon Creek.

Middle Fork Ranger District 1980 No data Circa 0.25 mile to 0.5 mile up IDFG Element Occurrence Hot Creek, Warm Spring Creek EO Number: 29 drainage. EO_ID: 3570

Middle Fork Ranger District 1986 No data Sheepeater Hot Springs, along IDFG Element Occurrence the Middle Fork of the Salmon EO Number: 30 River, Frank Church-River of No EO_ID: 3569 Return Wilderness

Middle Fork Ranger District

1992 400 ramets Warm Spring ca 1.25 miles up IDFG Element Occurrence Warm Spring Creek from EO Number: 44 Mormon Ranch, which is at the EO_ID: 3452 confluence of Warm Spring Creek with the Middle Fork Salmon River.

North Fork Ranger District

a. Are all Species Occurrences Only Accidental or Transient? Yes___ No_X_

If yes, document source for determination and stop assessment.

b. For species with known occurrences on the Forest since 1990, based on the number of observations and/or year of last observation, can the species be presumed to be established or becoming established in the plan area?

Yes_X__ No___

If no, provide explanation and stop assessment

c. For species with known occurrences on the Forest predating 1990, does the weight of evidence suggest the species still occurs in the plan area?

Yes__ No___

Provide explanation for determination N/A. Occurrences have been recorded since 1990. If determination is no, stop assessment

d. Map 1, Giant helleborine range in Idaho and surrounding states and provinces (NRCS 2017)

NRCS (United States Department of Agriculture, Natural Resources Conservation Service). 2017. Epipactis gigantea Douglas ex Hook. Stream orchid. Internet website: https://plants.usda.gov/core/profile?symbol=EPGI. Accessed on September 1, 2017.

e. Map 2, Giant helleborine observations on the Salmon–Challis National Forest (Idaho Fish and Wildlife Information System [January 2017])

3. Is There Substantial Concern for the Species’ Capability to persist Over the Long-term in the Plan Area Based on Best Available Scientific Information?

Table 2. Status summary based on existing conservation assessments

Entity Status/Rank (include definition if Other) Global Rank G4—Apparently Secure (Uncommon, but not rare)1

State Rank S3—Vulnerable (Vulnerable globally either because very rare and local throughout range, found only in a restricted range [even if abundant in some locations], or because of other factors making it vulnerable to extinction or elimination [typically 21 to 100 occurrences])1 USDA Forest Region 1: Bitterroot, Idaho Panhandle, Custer-Gallatin, Helena, Kootenai National Forests (Sensitive), Beaverhead-Deerlodge, Service Flathead, Lewis and Clark, Lolo, and Nez Perce National Forests (Known)2 Region 4: Not listed3 USDI FWS Not Listed as a candidate species4 5 Other Idaho Native Society: G3G4S3 RARE

BLM: Type 3 (Species that are globally rare or very rare in Idaho, with moderate endangerment factors. Their global or state rarity and the inherent risks associated with rarity make them imperiled species)6 1. Idaho Natural Heritage Program. 2016. IDNHP Tracked Plant Species 2016. On file. Accessed January 12, 2018 2. USFS Region 1. 2011. 2011 Sensitive Species List Idaho and Montana. Website: http://fsweb.r1.fs.fed.us/wildlife/wwfrp/TESnew.htm. Accessed January 10, 2017. 3. USFS Region 4. 2016. Proposed, Endangered, Threatened, and Sensitive Species List. On file. Accessed January 11, 2017. 4. USFWS. 2017. Candidate species believed to or known to occur in Idaho. Website: https://ecos.fws.gov/ecp0/reports/species-listed-by-state-report?state=ID&status=candidate. Accessed January 12, 2018. 5. Idaho Native Plant Society. 2018. INPS to Present at 2018 RPC. 2018 Idaho Rare Plant Conference. On file. Accessed March 1, 2018. 6. BLM. 2016. Bureau of Land Management Idaho Special Status Plants List Aug 2016. On file. Accessed 15 January, 2018.

Table 3. Status summary based on best available scientific information.

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations 1 A There are eight recorded occurrences of E. gigantea in four ranger districts, IDFG. 2017. Idaho Fish and Wildlife Distribution on which are distributed disjunctly across the north portion of SCNF with little Information System, Species Salmon–Challis opportunity for dispersal among patches (Rank A). Although a floristic Diversity Database, Idaho Natural National Forest inventory of the SCNF took place (Irwin 2014), targeted systematic surveys Heritage Data. Accessed on February have not been conducted. Potential habitat (see Criterion 6) is likely 27, 2017.

somewhat limited on the Forest. Irwin, J.J. 2014. A Floristic Inventory of East-Central Idaho, USA. Master’s Confidence in Rank: High, Medium, or Low thesis, University of Wyoming, Laramie.

2 C This species is known to occur in 14 western states and British Columbia NRCS (United States Department of Distribution in (NRCS 2017). This species is also widely distributed in Idaho (NRCS 2017). Agriculture, Natural Resources surrounding Since E. gigantea is well reported with wide distribution outside of the Conservation Service). 2017. The geographic area SCNF and throughout western North America, this criterion was ranked C. PLANTS database [Web Page]. Located at: National Plant Data Center, Baton Rouge, LA. Internet Confidence in Rank: High, Medium, or Low website: http://plants.usda.gov/plants/index. html. Accessed on September 1, 2017. 3 B E. gigantea disperses through wind-blown propagules and has the ability to Prendergast, G.1994. Growing Dispersal start new populations with the establishment of as little as a single Epipactis species from at Kew. Capability individual. This capability is due to E. gigantea populations existing with The Orchid Review 102:199-203. little or no genetic diversity. The flowering time for E. gigantea is for approximately two months during the summer season in Idaho, ranging Rocchio, J., M. March, and D. Anderson. 2006. Epipactis gigantea from as early as May to as late as August (Prendergast 1994; Smith and Dougl. Ex Hook. (stream orchid): A Read 1997). Technical Conservation Assessment. Prepared for the USDA Forest Service, Rocky Mountain Region,

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations The species’ genetic variability and ability to be self-compatible make it Species Conservation Project. well suited for establishment in geographically isolated areas – such as Colorado Natural Heritage Program, isolated seeps, hot springs, and wetlands. Once E. gigantea becomes Colorado State University, Ft. Collins, established in an area, it is likely that no new genetic material will migrate CO. into the population, keeping genetic variability low (Thornhill 1996; Rocchio Smith, S.E., and D.J. Read. 1997. et al. 2006). Mycorrhizal symbiosis. Ed. 2. Academic Press, San Diego, CA. E. gigantea is also known to spread through rhizomatous roots that grow laterally through suitable habitat (Rocchio et al. 2006). Thornhill, A. 1996. Species and occurrence-level patterns of genetic Although E. gigantea can establish a population with at minimum a single variation in Epipactis gigantea individual, its suitability of small, isolated warm and hot springs limits its (), with examination of dispersal capacity to rare habitats. Therefore, the criterion was ranked B. local genetic and clonal structure in riparian and bog occurrences Confidence in Rank: High, Medium, or Low inferred from allozyme analysis. Ph.D. Dissertation, University of California, Irvine, CA. 4 B EO records indicate that populations range from as few as ten to over 400 IDFG EO: Number 69 & EO_ID Abundance on individuals. Rocchio et al. (2006) suggest that correctly identifying E. 26736 the Salmon– gigantea from other orchids without is very difficult, and may have Challis National led to misidentification during previous surveys. Although there are Irwin, J.J. 2014. A Floristic Inventory Forest reported occurrences on the SCNF (Irwin 2014; IDFG 2016), it is likely that of East-Central Idaho, USA. Master’s thesis, University of Wyoming, the remoteness of many warm springs, and their fragility to disturbance Laramie. and hydrologic changes (Thornhill 1996; Rocchio et al. 2006), provide only partial evidence of the abundance of E. gigantea throughout the Forest. Rocchio, J., M. March, and D. Anderson. 2006. Epipactis gigantea Since there are a number of occurrences on the Forest, some with fairly Dougl. Ex Hook. (stream orchid): A Technical Conservation Assessment. abundant populations, this criterion is ranked B, uncommon. Prepared for the USDA Forest Service, Rocky Mountain Region, Confidence in Rank: High, Medium, or Low Species Conservation Project. Colorado Natural Heritage Program,

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations Colorado State University, Ft. Collins, CO.

Thornhill, A. 1996. Species and occurrence-level patterns of genetic variation in Epipactis gigantea (Orchidaceae), with examination of local genetic and clonal structure in riparian and bog occurrences inferred from allozyme analysis. Ph.D. Dissertation, University of California, Irvine, CA. 5 D Populations on the Forest have not been monitored consistently, and Irwin, J.J. 2014. A Floristic Inventory Population although Irwin (2014) relocated one population no monitoring was of East-Central Idaho, USA. Master’s Trend on the conducted at that time. No data is available to would provide population thesis, University of Wyoming, Salmon–Challis trends (Rank D). Laramie. National Forest Confidence in Rank: High, Medium, or Low 6 A The species is known to occur along streambanks, lake margins, seeps, and Google Earth. 2017. Salmon–Challis Habitat Trend especially near thermal waters, where most occurrences on the Forest are National Forest. Internet website: on the Salmon– documented. E. gigantea is always restricted to perennially moist, nutrient- https://www.google.com/earth/. Challis National rich habitats but many of the habitats are isolated and are rare warm Accessed on October 3, 2017. Forest springs with small habitat footprints (Roccio et al. 2006). Little is known IDFG. 2017. Idaho Fish and Wildlife about the soil requirements for the species, but it is believed to have a Information System, Species wide tolerance for pH (Roccio et al. 2006). Diversity Database, Idaho Natural Heritage Data. Accessed on February Considering known populations, aerial imagery, USFS GIS data, and EO 27, 2017. information was used to assess current habitat conditions and suggest that E. gigantea populations are experiencing moderate non-native plant cover IDFG. 2017b. Idaho State Wildlife and moderate to considerable anthropogenic disturbance. Aerial imagery Action Plan, 2015. Boise, ID. was assessed for the time periods between 1999 and 2017 and no evidence of residential or agricultural development or mining was depicted. Standing Rocchio, J., M. March, and D.

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations dead trees indicated wildfires at EO 9, 14, 15, 16, 27, and 44, while a Anderson. 2006. Epipactis gigantea mosaic of living and dead conifers indicated pine beetle infestations at EO Dougl. Ex Hook. (stream orchid): A 29 and 30. Technical Conservation Assessment. Prepared for the USDA Forest Active grazing allotments overlap EO 9 and EO 15 and animal trails were Service, Rocky Mountain Region, Species Conservation Project. noted at EO 14. A dirt road was identified near EO 15, and hiking trails were Colorado Natural Heritage Program, identified at each EO. Recreational activity including hiking and soaking in Colorado State University, Ft. Collins, thermal springs is popular and known to cause substantial impact in some CO. areas (SCNF pSCC working group, pers. commun.). Invasive plant species were mapped at EO 9, 15, 16, 27, and 44. Smith, G., Lemly, J., & Schroder, K. 2017. Fen mapping for the Salmon- In considering potential habitat, The Idaho State Wildlife Action Plan Challis National Forest. Colorado reports springs and groundwater dependent wetlands are in poor condition Natural Heritage Program, Colorado across all landownerships due to historic heavy grazing, continued season- State University, Fort Collins, CO. long grazing, development to provide livestock water, and OHV recreation (IDFG 2017b). The Spring Stewardship Institute has documented 669 USFS. 2016. SDE RMU Range Allotments. GIS Database springs and seeps on the SCNF. These were identified with the aid of the Information. Data source: National Hydrography Dataset GIS layer, which typically underestimates the S_R04_SCF.rmu_unit. Last updated true number of springs (USFS 2017). A recent assessment of spring March 30, 2016. distribution on the SCNF indicates that 97% of land type associations (LTAs) on the Forest have spring distribution within NRV. It is unknown how many USFS (United States Department of acres of high quality thermal wetland habitat exists on the Forest. Agriculture Forest Service). 2017a. Salmon-Challis National Forest Plan Within the SCNF, there has been historical degradation of suitable habitat Revision Assessments. Topics 1& 2: for this species and known populations are experiencing impacts from Terrestrial Ecosystems, Aquatic recreation and possibly grazing. Given this information, the lack of surveys Ecosystems, Watersheds, Air, Soil, to assess the quality of potentially suitable habitat, it is assumed current Water.

habitat trends may be declining in some places (Rank A).

Confidence in Rank: High, Medium, or Low

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations 7 A Potential threats to habitats of E. gigantea include invasive species Behrens, P.N., R.E. Keane, D.L. Vulnerability of infestations, grazing, recreation, hydrologic alterations, and climate change Peterson, and J.J. Ho. 2018. Chapter Habitats on the impacts (Jankovsky-Jones 1999; Rocchio et al. 2006). 6: effects of climatic variability and Salmon–Challis change on forest vegetation. In National Forest Invasive plant species have been mapped as overlapping a known Halofsky, J.E., D.L. Peterson, J.J. Ho, N.L. Little, L.A. Joyce, editors. 2018. occurrence of this species (see Criterion 6). Invasive plants have been Climate change vulnerability and identified as a major threat to the biological diversity and ecological adaptation in the Intermountain integrity within and outside the SCNF. Untreated invasive plant infestations Region. Gen. Tech. Rep. RMRS-GTR- have the potential to expand at an average rate of 1.3 to 25 percent per XXX. Fort Collins, CO: US Department year (USFS 2017). Invasive plants create many adverse environmental of Agriculture, Forest Service, Rocky effects, including, but not limited to: displacement of native plants; Mountain Research Station. reduction in functionality of habitat and forage for wildlife and livestock; threats to populations of threatened, endangered and sensitive species; Halofsky, J.E., D.L. Peterson, J.J. Ho, alteration of physical and biological properties of soil, including N.L. Little, L.A. Joyce, editors. 2018. productivity; changes to the intensity and frequency of fires; and loss of Climate change vulnerability and recreational opportunities (USFS 2017). adaptation in the Intermountain Region. Gen. Tech. Rep. RMRS-GTR-

xxx. Fort Collins, CO: US Department Grazing is an important land use on the SCNF contributing economically of Agriculture, Forest Service, Rocky and socio-culturally to the local communities (USFS 2017b). Grazing Mountain Research Station. allotments dominate SCNF landscapes outside of wilderness and research natural areas. Although roughly 23% of these allotments are currently IDFG (Idaho Department of Fish and vacant, grazing is expected to continue to be a dominant land use on the Game) GIS 2017. GIS data obtained Forest into the future. Inappropriately managed livestock grazing can by the Forest Service of species adversely affect the biota and hydrology of wetlands and riparian habitats occurrences on the Salmon–Challis (USFS 2017). National Forest and may include data from the Idaho Natural Mineral hot springs (and trails leading to them) where E. gigantea is known Heritage.

to occur are popular recreation destinations on the Forest and see Jankovsky-Jones, M. 1999. substantial use. The habitat surrounding these hot springs may be Conservation Strategy for Wetlands threatened by human trampling or pollution. Furthermore, human in East-Central Idaho. Idaho activities have the potential to considerably alter the chemistry of the Department of Fish and Game.

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations surrounding area, which may impact E. gigantea. Many potential smaller Natural Resource Policy Bureau, habitats, such as seeps and springs located in remote locations throughout Boise, ID. the Forest, are at a lower level of vulnerability and risk from human impact, but are subject to indirect disturbance from groundwater pollution and Joyce, L.A. and M. Talbert. 2018. alterations to surface water flow and drainage (Jankovsky-Jones 1999). Chapter 3: Historical and projected climate. In Halofsky, J.E., D.L.

Peterson, J.J. Ho, N.L. Little, L.A. To project the future climate and impacts to resources in the Joyce, editors. 2018. Climate change Intermountain Region including the Salmon-Challis, the Intermountain vulnerability and adaptation in the Adaptation Partnership (IAP) used Representative Concentration Pathway Intermountain Region. Gen. Tech. [RCP] 4.5 and 8.5, which capture a moderate and high future warming, Rep. RMRS-GTR-xxx. Fort Collins, CO: respectively (Halofsky et al. 2018). Although pathways predicting lower US Department of Agriculture, Forest warming exist, the 4.5 and 8.5 pathways were chosen by the IAP because Service, Rocky Mountain Research they are, in comparison, well studied providing a large set of projections Station. that enhance our understanding of the possible range in future climate. Thus, this represents best available science for our Forest with regard to a Mantas, M. 1993. Ecology and warming climate. Reproductive Biology of Epipactis gigantea Dougl. (Orchidaceae) in

Northwestern Montana. MS Thesis, Although uncertainty exists about the magnitude and rate of climate University of Idaho. change (For a discussion of this see Behrens et al. 2018), warming temperatures are the most certain consequence of increased CO2 in the Rocchio, J., M. March, and D. atmosphere. By 2100, median minimum temperature in the Middle Rockies Anderson. 2006. Epipactis gigantea subregion, which includes the Salmon-Challis, is projected to rise about 5˚F Dougl. Ex Hook. (stream orchid): A under the moderate warming scenario and about 10˚F under the high Technical Conservation Assessment. warming scenario. Regardless of scenario, the greatest departure from Prepared for the USDA Forest historical seasonal minimum temperatures occurs in the summer. Annual Service, Rocky Mountain Region, precipitation projections are highly variable with no discernible trend under Species Conservation Project. moderate warming and a slight increasing trend with high warming (Joyce Colorado Natural Heritage Program, Colorado State University, Ft. Collins, and Talbert 2018). CO.

Riparian and wetland communities in the Intermountain Region will be USFS (United States Department of moderately to highly vulnerable to climate warming depending on Agriculture Forest Service). 2017.

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations elevation (Halofsky et al. 2018). Plant communities composition and Salmon-Challis National Forest Plan structure will be affected by increased water stress, and this could drive the Revision Assessments. Topics 1& 2: replacement of riparian and wetland species with drought-tolerant upland Terrestrial Ecosystems, Aquatic species. This will be exacerbated where diversions and dams have been Ecosystems, Watersheds, Air, Soil, constructed. The adaptive capacity of systems will be greatly reduced Water.

where dewatering occurs and in systems impacted by improper grazing, USFS (United States Department of roads, and nonnative species (Halofsky et al. 2018). Changes in flow Agriculture, Forest Service). 2017b. regimes due to reduced snowpack, earlier snowmelt, and changes in Salmon–Challis National Forest Data precipitation could also drive changes in wetland species dependence on Assessment (Draft). On file at fluvial geomorphic processes, surface water, and groundwater (Halofsky et Salmon-Challis National Forest, al. 2018). Salmon, ID.

The degree to which both populations and habitats are vulnerable to loss or disturbance on the Forest are dependent upon variability in severity of impacts from climate change, habitat modification, and future grazing and recreation management decisions. Seep-springs and mineral hot springs are known to be highly susceptible to degradation and habitat loss (Mantas 1993) (Rank A).

Confidence in Rank: High, Medium, or Low 8 B E. gigantea flowers for approximately two months during summer, from Arditti, J., J.D. Michaud, and A.P. Life History and approximately May through early August (Brunton 1986). Reproduction Oliva. 1981. germination of Demographics occurs through microscopic seeds and through rhizomatous shoots that North American orchids, I. Native create clusters of clonal ramets (Brunton 1986). Average germination rates California and related species of for E. gigantea are approximately 20%, although seeds lose viability with Calypso, Epipactis, Goodyera, Piperia and Platanthera. Botanical Gazette. age (Arditti et al. 1981). A unique aspect of the life history of E. gigantea is 142(4): 442-453. its requirement of endomycorrhizal funal symbiot for the germination of seeds (Smith and Read 1997). Brunton, D.F. 1986. Status of the Giant Helleborine, Epipactis gigantea E. gigantea attracts generalist pollinators that include common yellow (Orchidaceae) in Canada. Canadian jackets, wasps, and syrphid flies amongst other insects (Burns-Balogh et al. Field-Naturalist. 100(3): 414-417.

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations 1987; Mantas 1993). Relationship with pollination agents does not likely limit this species. Burns-Balogh, P., D.L. Szlachetko, and A. Dafni. 1987. Evolution, Spring browsing by native wildlife has been noted on E. gigantea. Little is pollination, and systematics of the known regarding the parasites or disease in E. gigantea, however, a fungal tribe (Orchidaceae). Plant Systematics and Evolution. 156: 91- pathogen was observed in populations in Montana. The fungus damaged 115. and appeared to affect flowering production, but did not kill the plant (Rocchio et al. 2006). Mantas, M. 1993. Ecology and reproductive biology of Epipactis The low reproductive rate, combined with a strong fungal symbiotic gigantea Dougl. (Orchidaceae) in relationship, likely limits the species’ ability to recover from population northwestern Montana. Moscow, declines (Rank B). Since research into the life history and demographics of Idaho: University of Idaho. 73 p. both E. gigantea and plants of the orchid family are well known, confidence Thesis. in this ranking is high. Rocchio, J., M. March, and D. Confidence in Rank: High, Medium, or Low Anderson. 2006. Epipactis gigantea Dougl. Ex Hook. (stream orchid): A Technical Conservation Assessment. Prepared for the USDA Forest Service, Rocky Mountain Region, Species Conservation Project. Colorado Natural Heritage Program, Colorado State University, Ft. Collins, CO.

Smith, S.E., and D.J. Read. 1997. Mycorrhizal symbiosis. San Diego, California: Academic Press: 349-375. Summary and recommendations: Globally, E. gigantea is considered apparently secure, while in Idaho it is Date: 9/12/2017 considered vulnerable. There are eight known EOs on the Forest, with variable population sizes.

Species (Scientific and Common Name): Epipactis gigantea (Giant helleborine) Criteria Rank Rationale Literature Citations E. gigantea is a rhizomatous forb that is known to disperse through suitable habitat by seed and vegetatively through . The species has a moderate ability to disperse through suitable habitat, although populations are isolated and genetic diversity may be lose and pose potential threats to populations. The species is restricted to perennially moist habitats and is known to occur along streambanks, lake margins, seeps, and especially near thermal waters, where all occurrences on the Forest are documented.

The species is vulnerable to grazing, and unrestricted grazing should be considered a threat. Invasive species were documented and most EO records and pose a threat to populations. Recreational activities such as hiking and soaking in the thermal pools where this species occurs have likely caused a decline in habitat quality for the species. Further recreational development and unrestricted recreational activities should be considered threats to the populations. Climate change is projected to be a long-term threat to both populations and habitat for this species on the Forest.

There is concern for the capability of Epipactis gigantea to persist over the long-term on the Salmon-Challis, therefore, it is recommended as a SCC.

Evaluator(s): Spencer Rubin