SPECIES: Scientific [common] besseyi var. salmonensis – Barneby [Challis Crazyweed] Forest: Salmon–Challis National Forest Forest Reviewer: Brittni Brown; John Proctor Date of Review: 2 March 2018; 01 April 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.) June 18, Not Challis–Yankee Fork Ranger IDFG Element Occurrence EO 1979 reported District Number: 7 Lime Creek, Alt. 93 nearly 11.5 EO_ID: 4278 miles SE of Challis to Lime Creek Old EO_ID: 10888 Road, E to Section 31. 6,800 feet elevation. July 29, 400+ Challis–Yankee Fork Ranger IDFG Element Occurrence EO 1988 mature District Number:17 Gooseberry Spring, US Route EO_ID: 1418 93, cross Salmon River at Round Old EO_ID: 3710 Valley and E to road turning N, about 1.4 miles past the

Year Number of Location of Observations (USFS Source of Information Observed Individuals District, Town, River, Road Intersection, HUC, etc.) crossing. Turn on first road going E and follow to the end (turns to dirt). Gravelly to ashy reddish soil, sloping but not particularly unstable; N and S slopes, 0-20 degrees. 5,960 feet elevation. July 11, Not Lost River Ranger District, IDFG Element Occurrence EO 1975 reported Challis–Yankee Fork Ranger Number:25 District EO_ID: 284 Doublespring Pass, along dirt Old EO_ID: 1110 road between Dickey and May, at Doublespring Pass, on low ridge just south of the pass. Rocky soils, 8,350 feet in elevation. July 18, 76-150 Lost River Ranger District Irwin, J.J. 2014. “A Floristic 2011 plants Custer County, White Knob Inventory of East-Central Idaho, Mountains: head of Stag Creek USA.” Master’s thesis, where the ridge splits toward University of Wyoming, Castle Rock, 18.8 air mi W of Laramie. Mackay. Xeric, coarse textured soil on barren ground, 20-degree slope, SW aspect, trachyandesite geology, 8,885 feet in elevation. June 24, 76-150 Challis–Yankee Fork Ranger Irwin, J.J. 2014. “A Floristic 2011 plants District Inventory of East-Central Idaho, Custer County, Pahsimeroi USA.” Master’s thesis, Mountains: breaks on the east University of Wyoming, side of the Gerry Gulch Laramie. watershed, 8.5 air mi NE of Challis. Xeric soil within desert scrub vegetation, 17-degree slope, SW aspect, trachyandesite geology, 6,007 feet in elevation. August 16, 26-75 plants Challis–Yankee Fork Ranger Irwin, J.J. 2014. “A Floristic 2011 District Inventory of East-Central Idaho, Custer County, Salmon River USA.” Master’s thesis, Mountains: E of White Cloud University of Wyoming, Peaks: ridge dividing Pine and Laramie. Sheep Creeks, 25.6 air mi N of

Year Number of Location of Observations (USFS Source of Information Observed Individuals District, Town, River, Road Intersection, HUC, etc.) Sun Valley. Xeric soil within a forb dominated vegetation, 16- degree slope, WSW aspect, trachyandesite geology, 9,927 feet in elevation.

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, Challis crazyweed range in Idaho and surrounding states and provinces (NRCS 2017)

NRCS (United States Department of Agriculture, Natural Resources Conservation Service). 2017. Oxytropis besseyi (Rydb.) Blank. var. salmonensis Barneby, Salmon River . Internet website: https://plants.usda.gov/core/profile?symbol=OXBES. Accessed on October 17, 2017.

e. Map 2, Challis crazyweed occurrences on the Salmon–Challis National Forest (IDFG. 2017. Idaho Fish and Wildlife Information System, Species Diversity Database, Idaho Natural Heritage Data. Accessed on February 27, 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 G5T3+ — Vulnerable (At moderate risk of extinction due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors. A “+” follows the G and/or T rank if the species is an Idaho endemic and has the sole rank global and/or trinomial rank authority.)1 State Rank S3— Vulnerable (At moderate risk of extinction due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or other factors.)1 USDA Forest Region 1: Not listed2 Service Region 4: Sensitive Salmon–Challis National Forest3 USDI FWS Not listed as a candidate species4 Other Idaho Native Society: 2016 – on list, not yet ranked5; 2011 – GP36

BLM: Type 4 (These are species generally rare in Idaho with small populations or localized distribution and currently have low threat levels. However, due to the small populations and habitat area, certain future land uses in close proximity could significantly jeopardize these species.)7 1. Idaho Natural Heritage Program. 2016. IDNHP Tracked Plant Species 2016. 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. 2016. INPS Rare Plant List May 2016. https://idahonativeplants.org/rare-plants-list/ Accessed January 10, 2018. 6. Idaho Native Plant Society. 2011. Results of the twenty-fifth Idaho Rare Plant Conference – The Idaho Native Plant Society rare plant list. Website: https://idahonativeplants.org/rpc/pdf/2011_Results_IRPC_v2.2.pdf. Accessed on January 11, 2018. 7. 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): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations 1 B1 Challis crazyweed is known from three historic (predating 1990) IDFG. 2017. Idaho Fish and Wildlife Distribution on occurrences and three contemporary (post-1990) occurrences on the Information System, Species Diversity Salmon–Challis Salmon–Challis National Forest (IDFG 2017). Of the historic occurrences, Database, Idaho Natural Heritage National Forest two are from the Challis–Yankee Fork Ranger District, and one is from the Data. Accessed February 27, 2017. Lost River Ranger District. Of the contemporary occurrences, two are Irwin, J.J. 2014. “A Floristic Inventory from the Challis–Yankee Fork Ranger District, and one is from the Lost of East-Central Idaho, USA.” Master’s River Ranger District. Although, a floristic inventory of the SCNF took thesis, University of Wyoming, place (Irwin 2014), targeted systematic surveys have not been Laramie. conducted. Spahr, R., L. Armstrong, D. Atwood, Challis crazyweed is a narrow endemic variety restricted to the and M. Rath. 1991. Threatened, immediate vicinity of the Salmon River Canyon generally between endangered, and sensitive species of Clayton, downstream to the north of Challis and Mackay, in Custer the Intermountain Region. U.S. Forest County (Spahr et al. 1991). Irwin (2014) encountered Challis crazyweed in Service, Intermountain Region, Ogden, scattered, isolated populations “at all elevations” in the dry mountains of Utah. the East Fork Salmon River and Big Lost River watersheds on the Salmon– Challis National Forest. Irwin noted that this taxon was previously unknown from alpine-subalpine elevations and that additional surveys are warranted.

Suitable habitat for Challis crazyweed (see Criterion 6) is likely distributed as patches within suitable volcanic substrates; some patches may be small or isolated to the degree that species interactions are limited by movements between patches. Local sub-populations may act as a meta- population or a patchy population. For these reasons, this criterion was ranked “B1.”

Confidence in Rank: High, Medium, or Low

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations 2 B Challis crazyweed is a narrow Idaho endemic; its distribution is limited to Barneby, R. C. 1952. “A Revision of the Distribution in the Salmon River, Big Lost River, and Pahsimeroi River canyons in Custer North American Species of Oxytropis surrounding County in central Idaho (NatureServe 2017). DC.” Proceedings of the California geographic area Academy of Sciences, Fourth Series. Outside of the Forest, this species occurs in the immediate vicinity of the Volume XXVII. San Francisco, California. Pp 234-235. Big Lost River canyon (Barneby 1952) and Salmon River canyon generally

between Clayton, downstream to north of Challis and Mackay, in Custer CPNWH (Consortium of Pacific County (Spahr et al. 1991). The Consortium of Pacific Northwest Herbaria Northwest Herbaria). 2017. Specimen has recorded 23 occurrences of this species in Custer County, apparently Database Query – Oxytropis besseyi including those on the Forest (CPNWH 2017). var. salmonensis. Internet website: http://www.pnwherbaria.org/data/ . This species has a limited distribution outside of the Salmon–Challis Accessed October 17, 2017. National Forest, so this criterion was ranked “B.” Confidence in this ranking is high because there are multiple records of this species outside NatureServe. 2017. NatureServe of the Forest in Custer County. Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia Confidence in Rank: High, Medium, or Low Internet website: http://explorer.natureserve.org/index. htm. Accessed October 17, 2017.

Spahr, R., L. Armstrong, D. Atwood, and M. Rath. 1991. Threatened, endangered, and sensitive species of the Intermountain Region. U.S. Forest Service, Intermountain Region, Ogden, Utah. 3 B Literature describing the dispersal strategies or capability of Challis Barneby, R. C. 1952. “A Revision of the Dispersal crazyweed is not available; however, the dispersal strategy may be North American Species of Oxytropis Capability inferred by examining the preferred habitat and lifeform. As shown in DC.” Proceedings of the California Table 1, this species occupies a variety of aspects, landforms, and slopes Academy of Sciences, Fourth Series. Volume XXVII. San Francisco,

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations in shrub-steppe and desert scrub vegetation. Reviewing observation California. Pp 234-235. records in the CPNWH (2017) yields similar findings. Further, Barneby (1952) describes the seedpods as “strongly inflated.” Given the varied CPNWH (Consortium of Pacific microhabitats the species grows in, and the inflated nature of the Northwest Herbaria). 2017. Specimen seedpods, it is likely that wind and water both play a role in seed Database Query – Oxytropis besseyi var. salmonensis. Internet website: dispersal. http://www.pnwherbaria.org/data/ . Accessed October 17, 2017. Spahr et al. (1991) also note that it often grows where subject to rapid soil erosion, indicating that mass soil movement and gravity may also Spahr, R., L. Armstrong, D. Atwood, serve to disperse seed. This dispersal method likely transports seeds and M. Rath. 1991. Threatened, smaller distances than wind and water. Birds and small mammals may endangered, and sensitive species of also transport seeds between patches of suitable habitat. the Intermountain Region. U.S. Forest Service, Intermountain Region, Ogden, Challis crazyweed disperses only through suitable habitats. Since suitable Utah. habitats are non-ephemeral, dispersal may play a less critical role in population dynamics. For these reasons, this criterion was ranked “B.” Because specific studies for the dispersal capabilities of this taxon have not been completed, confidence is low.

Confidence in Rank: High, Medium, or Low 4 A Challis crazyweed is known from three historic and three contemporary IDFG. 2017. Idaho Fish and Wildlife Abundance on the occurrences from two Ranger Districts; the Challis–Yankee Fork and Lost Information System, Species Diversity Salmon–Challis River Ranger Districts (IDFG 2017). EO 17 is the only historic occurrence Database, Idaho Natural Heritage National Forest to report abundance; at this location, over 400 individuals were observed Data. Accessed February 27, 2017. in 1988. At EO 7 (1979), the observed noted the species was “common in Irwin, J.J. 2014. “A Floristic Inventory rocky volcanic soil.” At contemporary observations, Irwin (2014) reported of East-Central Idaho, USA.” Master’s a range of individuals between 26 and 75 (one occurrence) and 75 and thesis, University of Wyoming, 150 (two occurrences). Laramie.

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations As described in Criteria 1, Irwin (2014) found the species at higher elevations than had previously been reported, and notes that additional surveys are warranted. This indicates that abundance on the Forest may be under-reported.

Nonetheless, the low number of known occurrences, and the low number of individuals observed at occurrences where reported, indicate that this species is likely rare on the Forest. Current abundance is low enough that stochastic and other factors could lead to potential imperilment. Thus, this criterion was ranked “A.” Because the full abundance of this taxon on the Forest is likely not well known, confidence is somewhat lowered.

Confidence in Rank: High, Medium, or Low 5 D Little information exists to be able to draw conclusions about the Population Trend population trend of Challis crazyweed on the Salmon–Challis National on the Salmon– Forest, because known occurrences have not been monitored Challis National consistently. Further, precise population data is not known at most Forest known occurrences (Rank D)

Confidence in Rank: High, Medium, or Low 6 A O. besseyi var. salmonensis grows in fine talus and ash in sandy wash or Barneby, R. C. 1952. “A Revision of the Habitat Trend on open lower slopes within the shrub-steppe, often where subject to rapid North American Species of Oxytropis the Salmon–Challis soil erosion (Spahr et al. 1991). Barneby (1952), in describing the species, DC.” Proceedings of the California National Forest noted that it occupies friable clay declivities along the Salmon and Big Academy of Sciences, Fourth Series. Lost Rivers in Custer County, and is found “in some quantity” on soft, Volume XXVII. San Francisco, California. Pp 234-235. shaley clay banks of lateral canyons leading into the Salmon River Gorge.

Barren, rocky outcrops are estimated to account for approximately 3% of Google Earth. 2017. Salmon–Challis land cover (based on Landfire biophysical settings). It is unclear what National Forest. Internet website: percentage of this habitat type occurs within the appropriate elevational https://www.google.com/earth/.

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations band for this species. Accessed on October 18, 2017.

Dry, open sagebrush communities that are generally associated with IDFG. 2017. Idaho Fish and Wildlife habitat descriptions for this species outside of the SCNF are relatively Information System, Species Diversity common on the Forest. The Idaho Wildlife Action Plan (IDFG 2017b) Database, Idaho Natural Heritage Data. Accessed February 27, 2017. indicates sagebrush habitats on the SCNF have “high ecological integrity

relative to other Idaho Sections based on their large spatial extent, IDFG. 2017b. Idaho State Wildlife contiguous distribution, and comparatively low human footprint.” Action Plan, 2015. Boise, ID. However, historical land management practices have often negatively impacted native sagebrush steppe communities, and alongside fire Schuldt, D. 2015. Salmon–Challis suppression policies, is thought to be a contributor to annual grass National Forest Invasive Plant invasions and conifer encroachment. Treatment – Sensitive Plant Report prepared in support of the DEIS and Aerial imagery (1992-2016) of habitat at each occurrence was assessed FEIS. for ground disturbing activities which might result in an impact to habitat (Google Earth 2017). Examples of significant ground-disturbing events Spahr, R., L. Armstrong, D. Atwood, and M. Rath. 1991. Threatened, include agricultural or residential development, wildfires, roads or trails, endangered, and sensitive species of mining, and livestock grazing. Further, a database of existing grazing the Intermountain Region. U.S. Forest allotments on the Forest was queried for allotments that overlapped any Service, Intermountain Region, Ogden, population (USFS 2016). A database of known invasive plant populations Utah. was also reviewed for nearby plant invasions. A database of historical wildfires in the area was reviewed as wildfires may degrade habitat. USFS. 2016. SDE RMU Range Notes from historical collections were also reviewed as they contain Allotments. GIS Database Information. information on threats to habitat (IDFG 2017). Data source: S_R04_SCF.rmu_unit. Last updated March 30, 2016. The results of the imagery and database analysis indicated that there was no residential or agricultural development at any EO. Likewise, no

evidence of wildfires or mining was observed.

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations All occurrences were within an active livestock grazing allotment. Habitat at EO 17 may be the most affected by livestock grazing. A cattle trough is visible less than 0.1 mile from the EO boundary, and numerous animal trails radiate from this trough through the occurrence (Google Earth 2017). A dirt road traverses the edge of the EO17, and multiple fence lines are visible in and near the occurrence. Other EOs display indicators of less intense impacts, such as visible game/cattle paths through vegetation, but they lack obvious visible grazing infrastructure. In the account for this species in Spahr et al. (1991), livestock grazing and grazing by antelope are identified as potential management implications which may affect populations.

Habitat at EO 25 is likely affected by road development. This occurrence is located at Doublespring Pass, on a low ridge near the pass (Google Earth 2017). A review of the imagery reveals several fence lines, old dirt road cuts, and other surface disturbance associated with Doublespring Road near the occurrence.

Musk thistle is mapped extensively on the east side of the pass along the road, and bull thistle is likewise mapped on the west side of the pass along the road at EO 25. The Forest invasive plant treatment EIS rare plant report (Schuldt 2015) notes that Challis crazyweed is present near some roads, and that its habitat is susceptible to invasion.

While past and present habitat trends for this species have not been researched, observations on trends of rangeland productivity suggest that habitat for this species is vulnerable. There is some evidence to suggest that there has been a downward trend in habitat quality, thus this criterion was ranked “A.” Confidence in this rank is lowered as there have been no site visits to confirm the condition of habitat.

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations

Confidence in Rank: High, Medium, or Low

7 B Within suitable shrub-steppe habitat for this species, the most significant Behrens, P.N., R.E. Keane, D.L. Vulnerability of drivers would likely be unrestricted livestock grazing, invasive species, Peterson, and J.J. Ho. 2018. Chapter 6: Habitats on the and changes in climate. effects of climatic variability and Salmon–Challis change on forest vegetation. In National Forest The effects of grazing on Challis crazyweed have not been researched. Halofsky, J.E., D.L. Peterson, J.J. Ho, N.L. Little, L.A. Joyce, editors. 2018. However, potential impacts include trampling of individual plants, as well Changes in climate vulnerability and as the defoliation and removal of palatable plant species, which changes adaptation in the Intermountain plant community structure, soil compaction, abrasion, and Region. Gen. Tech. Rep. RMRS-GTR- destabilization, and redistribution of soil nutrients and ecological XXX. Fort Collins, CO: US Department succession (Fleischner 1994). As the actual extent of the impacts from of Agriculture, Forest Service, Rocky grazing are unknown, the threat may be considered as low. Mountain Research Station.

Grazing is an important land use on the SCNF contributing economically Fleischner, T. L. 1994. “Ecological Costs and socio-culturally to the local communities (USFS 2017b). Grazing of Livestock grazing in Western North allotments dominate SCNF landscapes outside of wilderness and research America.” Conservation Biology. 8(3): natural areas. Although roughly 23% of these allotments are currently 629-644.

vacant, grazing is expected to continue to be a dominant land use on the Halofsky, J.E., D.L. Peterson, J.J. Ho, Forest into the future. N.L. Little, L.A. Joyce, editors. 2018. Changes in climate vulnerability and Invasive plant species have been mapped as overlapping a known adaptation in the Intermountain occurrence of this species (see Criterion 6). Invasive plants have been Region. Gen. Tech. Rep. RMRS-GTR- identified as a major threat to the biological diversity and ecological xxx. Fort Collins, CO: US Department of integrity within and outside the SCNF. Untreated invasive plant Agriculture, Forest Service, Rocky infestations have the potential to expand at an average rate of 1.3 to 25 Mountain Research Station. percent per year (USFS 2017). Invasive plants create many adverse environmental effects, including, but not limited to: displacement of Hatfield, R., Jepsen, S., Mader, E., native plants; reduction in functionality of habitat and forage for wildlife Black, S.H., Shepherd, M. 2012.

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations and livestock; threats to populations of threatened, endangered and Conserving bumble bees: guidelines sensitive species; alteration of physical and biological properties of soil, for creating and managing habitat for including productivity; changes to the intensity and frequency of fires; America’s declining pollinators. The and loss of recreational opportunities (USFS 2017). Xerces Society for Invertebrate Conservation.

To project the future climate and impacts to resources in the Joyce, L.A. and M. Talbert. 2018. Intermountain Region including the Salmon-Challis, the Intermountain Chapter 3: Historical and projected Adaptation Partnership (IAP) used Representative Concentration climate. In Halofsky, J.E., D.L. Peterson, Pathway [RCP] 4.5 and 8.5, which capture a moderate and high future J.J. Ho, N.L. Little, L.A. Joyce, editors. warming, respectively (Halofsky et al. 2018). Although pathways 2018. Changes in climate vulnerability predicting lower warming exist, the 4.5 and 8.5 pathways were chosen by and adaptation in the Intermountain the IAP because they are, in comparison, well studied providing a large Region. Gen. Tech. Rep. RMRS-GTR- set of projections that enhance our understanding of the possible range xxx. Fort Collins, CO: US Department of in future climate. Thus, this represents best available science for our Agriculture, Forest Service, Rocky Forest with regard to a warming climate. Mountain Research Station.

Miller-Struttmann, N.E., Geib, J.C., Although uncertainty exists about the magnitude and rate of changes in Franklin, J.D., Kevan, P.G., Holdo, R.M., climate (For a discussion of this see Behrens et al. 2018), warming Ebert-May, D., Lynn, A.M., Kettenbach, temperatures are the most certain consequence of increased CO2 in the J.A., Hedrick, E., Galen, C. 2015. atmosphere. By 2100, median minimum temperature in the Middle Functional mismatch in a bumble bee Rockies subregion, which includes the Salmon-Challis, is projected to rise pollination mutualism under changes about 5˚F under the moderate warming scenario and about 10˚F under in climate. Science, 349(6255): 1541- the high warming scenario. Regardless of scenario, the greatest 1544. departure from historical seasonal minimum temperatures occurs in the summer. Annual precipitation projections are highly variable with no USFS (United States Department of discernible trend under moderate warming and a slight increasing trend Agriculture Forest Service). 2017. with high warming (Joyce and Talbert 2018). Salmon-Challis National Forest Plan Revision Assessments. Topics 1& 2:

Terrestrial Ecosystems, Aquatic Under changes in climate scenarios, sagebrush steppe habitats and Ecosystems, Watersheds, Air, Soil, adjacent rocky outcroppings are projected to experience an increased Water.

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations risk of wildfires and greater risk of invasive species invasion (which tend to become more frequent with wildfires outside of natural fire regimes in USFS (United States Department of this habitat type), such as cheatgrass, halogeton, and Russian thistle Agriculture, Forest Service). 2017b. (Halofsky et al. 2018). The invasion of cheatgrass can increase the fire- Salmon–Challis National Forest Data return intervals, further exasperating threats. Warmer temperatures and Assessment (Draft). On file at Salmon- decreased precipitation may also impact sagebrush steppe communities. Challis National Forest, Salmon, ID. Ultimately, dry sagebrush types such as Wyoming big sagebrush are highly vulnerable and have one of the lowest adaptive capacities to projected changes in climate impacts (Halofsky et al. 2018).

Changes in temperature and precipitation may also lead to greater variability in forb flowering, which could create an asynchronistic effect with native pollinator emergence (Halofsky et al. 2018; Miller-Struttmann et al. 2015), leading to decreased reproduction in native plants. As pollinators are critical for successful reproduction and seed set for approximately 85% of flowering species globally (Hatfield et al. 2012), this asynchronistic effect may have profound implications.

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 changes in climate, invasive species, and future grazing management decisions (Rank B).

Confidence in Rank: High, Medium, or Low 8 A Challis crazyweed is a low, tufted perennial herb in the pea family Barneby, R. C. 1952. “A Revision of the Life History and (). Plants are tap-rooted and long-lived. It flowers from June to North American Species of Oxytropis Demographics July, and produces strongly inflated seed pods (Barnaby 1952; Spahr et DC.” Proceedings of the California al. 1991). It is unknown if this species maintains a large, dormant seed Academy of Sciences, Fourth Series. bank in the soil; however, this strategy is employed by another perennial Volume XXVII. San Francisco, California. Pp 234-235. member of this genus in the Rocky Mountains, whitepoint locoweed

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations (Oxytropis sericea) (Esser 1993). This trait would enable the species to CPNWH (Consortium of Pacific take advantage of favorable environmental conditions (Ralphs et al. Northwest Herbaria). 2017. Specimen 1989). Database Query – Oxytropis besseyi var. salmonensis. Internet website: Pollinators for this species have not been described. Seed dispersal http://www.pnwherbaria.org/data/ . Accessed October 17, 2017. mechanisms are unknown, but the landscape position of habitat suggests

wind, water, and potentially soil movement and gravity as potential Ellstrand, N. C., and D. R. Elam. 1993. dispersal mechanisms; but other biotic mechanisms may also be “Population genetic consequences of important (see Criterion 3). The germination rates for this species are small population size: Implications for also unknown. plant conservation.” Annual Reviews of Ecology and Systematics. 24: 217- Little is known of the demographics of this species. There are seven 242. known populations of this species on the Forest and 23 occurrences have been documented in the region (CPNWH 2017) database. There is some Esser, L. L. 1993. Oxytropis sericea. In: evidence to suggest that the populations are small and somewhat Fire Effects Information System, isolated (see Table 1 and Criterion 4). [Online]. U.S. Department of Agriculture, Forest Service, Rocky

Mountain Research Station, Fire The impacts of a small population may include reduced genetic diversity Sciences Laboratory. Internet website: and fitness (Ellstrand and Elam 1993). Reduced genetic diversity and https://www.fs.fed.us/database/feis/p fitness can be a result of genetic drift and inbreeding. Genetic drift and lants/forb/oxyser/all.html#30. inbreeding is most likely to occur in small (less than 100 individuals) and Accessed October 18, 2017. isolated populations (Ellstrand and Elam 1993). Also, small populations may be more vulnerable to stochastic events that may result in a local Ralphs, M. H., B. Benson, and J. C. extinction. Small populations may also be less able to recover rapidly Loerch. 1989. “Soil-site relationships of following a disturbance. white locoweed on the Raft River Mountains.” Great Basin Naturalist The species has demographic characteristics that suggest populations 49(3): 419-424.

may not recover rapidly from disturbance events and this species may Spahr, R., L. Armstrong, D. Atwood, also be prone to reduced fitness from a lack of genetic diversity. and M. Rath. 1991. Threatened, Therefore, this criterion was ranked “A.” Confidence in this rank is endangered, and sensitive species of

Species (Scientific and Common Name): Oxytropis besseyi var. salmonensis (Challis crazyweed)

Criteria Rank Rationale Literature Citations lowered somewhat due to the historic nature of the majority of most the Intermountain Region. U.S. Forest occurrences on the Forest, undocumented population size of most Service, Intermountain Region, Ogden, populations on the Forest, and potentially poorly-known extent of Utah. populations on the Forest.

Confidence in Rank: High, Medium, or Low Summary and recommendations: Challis crazyweed, a narrow Idaho and “Challis endemic” only found in Custer Date: 10/18/2017 County, is considered vulnerable at the global (G5T3+) and state (S3) levels. It is a Forest Service Region 4 Sensitive species, and BLM Type 4 species. Abundance is low enough that the species is likely susceptible to stochastic events on the Forest.

This species is known from shrub-steppe habitat on volcanic deposits, in the immediate vicinity of the Salmon River, Big Lost River, and Pahsimeroi River canyons. The species is known from six occurrences on the Forest (three of which are historic). Population trends have not been monitored on the Forest. Habitat trends are likely declining. Many EO records have documented potential impacts from grazing activities; unrestricted livestock grazing should be considered a substantial threat to populations. The invasive species musk thistle and bull thistle have been documented near populations and likely pose a threat. Road development has likely impacted habitat for the species and further development would be a threat for some occurrences. Changes in climate is projected to have long-term impacts on the habitat for this species on the Forest.

There is substantial concern for the capability of Oxytropis besseyi var. salmonensis to persist over the long-term on the Salmon-Challis, therefore, it is recommended as a SCC.

Evaluator(s): Morgan Trieger