SPECIES: Scientific [Common] Bombus Occidentalis [Western
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SPECIES: Scientific [common] Bombus occidentalis [Western bumble bee] Forest: Salmon-Challis National Forest Forest Reviewer: Mary Friberg Date of Review: 2/23/2018 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.) 2017 1 Salmon-Cobalt Ranger District Personal communication, Katherine Baumann (November 6, 2017) 1993 1 Cobalt Ranger Station (Lemhi The Global Biodiversity County) Information Facility Occurrence Download (October 2017) 1967 26 8 miles south of Cobalt, ID The Global Biodiversity (Lemhi County) Information Facility Occurrence Download (October 2017) 2017 1 Donnelly Gulch (Lemhi County) Personal communication, Katherine Baumann (November 6, 2017) 1967 3 3 miles north of North Fork, ID The Global Biodiversity (Lemhi County) Information Facility Occurrence Download (October 2017) 1965 8 5 miles north of North Fork, ID The Global Biodiversity (Lemhi County) Information Facility Occurrence Download (October 2017) 1934, 1960 21 Gibbonsville, ID (Lemhi County) The Global Biodiversity Information Facility Occurrence Download (October 2017) 1940 6 ~12 miles SW of North Fork, ID The Global Biodiversity (Lemhi County) Information Facility Occurrence Download (October 2017) 1926 1 Middle Fork, Salmon River The Global Biodiversity (Lemhi County) Information Facility Occurrence Download (October 2017) 1966 1 Jordan Creek (Custer County) The Global Biodiversity Information Facility Occurrence Download (October 2017) 1974 1 Elk Creek Ranger Station (Valley The Global Biodiversity County) Information Facility Occurrence Download (October 2017) 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 documented since 1990 If determination is no, stop assessment d. Map 1, Western bumble bee range in Idaho (IDFG 2017a) IDFG (Idaho Department of Fish and Game). 2017. Western bumble bee (Bombus occidentalis). Internet website: https://idfg.idaho.gov/species/taxa/ 78169. Accessed on October 23, 2017. e. Map 2, Western bumble bee occurrences 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) NatureServe G4- Apparently secure (Uncommon but not rare; some cause for long-term concern due to declines or other factors) Global Rank NatureServe S3- Vulnerable (due to a restricted range, relatively few populations (often 80 or fewer), recent and widespread declines, or State Rank other factors making it vulnerable to extirpation. State List IDAPA- Arthropod Status SGCN- Tier 1 (Highest priority for the SWAP; represents species with the most critical conservation needs, i.e., an early-warning list of taxa that may be heading toward extirpation) USDA Forest No Region 1 Status Service No Region 4 Status USDI FWS No species profile Other Not BLM Type 2 Xerces Society Red List Species – Imperiled (At high risk of extinction due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors.) Table 3. Status summary based on best available scientific information. Species (Scientific and Common Name): Bombus occidentalis [Western bumble bee] Criteria Rank Rationale Literature Citations 1 B2 The Western bumble bee is a year-round resident of the Salmon-Challis Distribution on National Forest (IDFG 2017a). Its estimated range encompasses all of the Salmon-Challis Forest (see Map 1). In historic surveys, it was widely distributed on the National Forest Forest (see Table 1). Since 1998, however, the Western bumble bee has experienced significant population (see Criterion 5) and range (see Criterion 2) declines, and using historic occurrence records to determine Cameron et al. 2011. Patterns of present distribution would likely overestimate its current presence widespread decline in North (Cameron et al. 2011). 2017 surveys found occurrences on the Salmon- American bumble bees. Cobalt Ranger District, confirming its presence on the Forest (see Table Proceedings of the National 1). Due to its mobility (see Criterion 3) and habitat requirements (see Academy of Sciences: Vol. 108: No. Criterion 6), potential habitat is widely distributed across the Forest, and 2. connectivity between habitat patches is good. Based on distribution maps and habitat requirements, the Western IDFG (Idaho Department of Fish bumble bee is probably widely distributed across the Forest in patches of and Game). 2017a. Western suitable habitat, exhibiting metapopulation dynamics with some isolated bumble bee (Bombus occidentalis). subpopulations (Rank B2). Confidence in this assessment is low, however, Internet website: considering recent population trends and limited recent current https://idfg.idaho.gov/species/taxa occurrence data. /78169. Accessed on October 23, 2017. Confidence in Rank: High, Medium, or Low Species (Scientific and Common Name): Bombus occidentalis [Western bumble bee] Criteria Rank Rationale Literature Citations 2 C The Western bumble bee is widely distributed in western North America Cameron et al. 2011. Patterns of Distribution in (NatureServe 2017). Its western distribution ranges from southern British widespread decline in North surrounding Columbia to central California and extends eastward to the Dakotas, American bumble bees. geographic area Nebraska, Colorado, and New Mexico (NatureServe 2017). Additional Proceedings of the National populations of the subspecies Bombus occidentalis mckayi occur in Academy of Sciences: Vol. 108: No. northern British Columbia, Yukon, and Alaska (NatureServe 2017). 2. Bombus occidentalis has been documented from sea level to over 2,000 m (Williams et al. 2014 in Hatfield et al. 2015). Recent surveys have Hatfield, R., S. Jepsen, R. Thorp, L. documented its presence in the Rocky Mountains, but the current range Richardson, S. Colla, and S. Foltz of the Western Bumble bee is estimated to be reduced by 28% from Jordan. Bombus occidentalis. The historic occurrences, particularly along the western margin of its range IUCN Red List if Threatened Species (Cameron 2011). Statewide conservation assessments indicate that the 2015: e.T44937492A46440201. Western bumble bee is critically imperiled along the western edge of its http://dx.doi.org/10.2305/IUCN.UK distribution. Recent surveys have confirmed its persistence in northern .2015- Idaho (Rhoades et al. 2016). 2.RLTS.T44937492A46440201.en NatureServe. 2017. NatureServe Despite recent range contractions, the Western bumble bee is still widely Explorer: An online encyclopedia of distributed outside the Salmon-Challis National Forest (Rank C). life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Confidence in Rank: High, Medium, or Low Internet website: http://explorer.natureserve.org. Accessed on August 29, 2017. Rhoades et al. 2016. Evidence for Bombus occidentalis (Hymenoptera: Apidae) populations in the Olympic Peninsula, the Palouse Prairie, and Forests of Northern Idaho. Journal of Insect Science: Vol. 16: No. 1. 3 C The Western bumble bee is a central place forager, meaning that Hatfield, R., S. Jepsen, R. Thorp, L. Dispersal foraging adults depart from and return to a fixed colony location. It is Richardson, S. Colla, and S. Foltz Capability also a social species, producing individuals that belong to either a non- Jordan. 2015. Bombus occidentalis. mating worker caste or a reproductive caste. Mated females (gynes) The IUCN Red List of Threatened leave their natal nest to establish new colonies; therefore movement of Species 2015: gynes, not workers, is the source of genetic and colonial dispersal. eT44937492A46440201. Temporally, dispersal is limited to the late summer or fall, when mated gynes leave their natal nest, and early spring, when mated gynes Lepais et al. 2010. Estimation of (queens) establish new colonies (Hatfield et al. 2015). Studies in the UK bumblebee queen dispersal that used a conservative method to estimate dispersal distances of distances