SPECIES EVALUATION Erigeron humilis, Priority 1. Erigeron humilis Graham (ERHU). low fleabane, arctic alpine fleabane. CNHP G4 / S1, Track A G4 N?. CO S1, WY S2. WY Disjunct, 6 SNF, 1 BNF;GMUG-Taylor River-Cebolla, ARP-Clear Creek, WR-Aspen Confi- Criteria Rank dence Rationale Sources of Information Distribution in R2 is patchy, so I have ranked B; but the terminology in the Specimens at COLO and RM, Dorn 2001, 1 discussion does not apply to this plant, hence the low confidence. Weber and Wittmann 2001a, Fertig 2000. Distribution B L Ranked S1 in Colorado and S2 in Wyoming; not ranked in Montana. Unknown within R2 whether ranked in Utah. The plants are small and inconspicuous; I estimate that 10-15 more sites remain to be discovered in Colorado and Wyoming. Widespread across northern Canada and the Northern Rockies, in Alaska and Hultén 1968. 2 western Siberia. Distribution C H outside R2 “It may be inferred that the bristly pappus is appropriate for wind dispersal across 3 unsuitable habitat” (Handley and Laursen 2002), but this is really unknown. Dispersal D L Capability Most populations have been reported to be relatively small (10-25 individuals in one Handley and Laursen 2002, Fertig 2000, 4 survey in Wyoming). About ten occurrences in Wyoming and six to eight in Colorado; my observations. Abundance in B M three or four in Utah. R2 “Presumed to be stable at present, although no trend data are available” (Fertig Fertig 2000, my observations. 5 2000). Population B L Trend in R2 Alpine “granite and limestone cliff faces, talus slopes, alpine meadows and tundra. Fertig 2000, Weber and Wittmann 2001a, Often in mossy, moist microsites” (Fertig 2000). “Extremely rare, mossy tundra on Dorn 2001. 6 high peaks … The plants are minute, less than 3 cm tall; the heads are on very short Habitat Trend B M stems no longer than the basal leaves” (Weber and Wittmann 2001a). in R2 Many of these sites are fairly stable at present, but we have no monitoring data specific to Erigeron humilis. Many habitats occur in wilderness areas and other lightly-protected areas. Habitats Fertig 2000, my observations. 7 in scree slopes and on cliffs are not vulnerable, but grassy tundra might be, depending Habitat C M on whether it is located near a trail or other route. Recreational use of these areas is Vulnerability or steadily increasing every year, but I expect the habitats overall will be fairly resilient to Modification the moderate disturbance they are likely to get. Nothing known of life history and demographics. 8 Life History and D H Demographics 1 SPECIES EVALUATION National Forests in the Rocky Mountain Region where species is KNOWN (K) or LIKELY (L)* to occur: *. Likely is defined as more likely to occur than not occur on the National Forest or Grassland. This generally can be thought of as having a 50% chance or greater of appearing on NFS lands. COLORADO NF/NG K L K L K L Arapaho-Roosevelt NF K NEBRASKA NF/NG WYOMING NF/NG White River NF K Samuel R. McKelvie NF Shoshone NF K Routt NF Halsey NF Bighorn NF K Grand Mesa Uncompahgre Gunnison NF K Nebraska NF Black Hills NF San Juan NF K Ogalala NG Medicine Bow NF Rio Grande NF SOUTH DAKOTA NF/NG Thunder Basin NG Pike-San Isabel NF Black Hills NF KANSAS NF/NG Comanche NG Buffalo Gap NG Cimarron NG Pawnee NG Ft. Pierre NG Taxonomy. Erigeron humilis is accepted as a species by many botanists, but a few call these plants E. uniflorus var. unalaschkensis. I prefer E. humilis. Discussion. This is a tiny plant, easily missed, and there are probably several to many more sites awaiting discovery. Most populations appear small to very small in number, but the habitats are mostly protected and not very vulnerable. Erigeron humilis does not seem to have great concerns for viability in R2 at this time. References Albee, Beverly J.; Leila M. Shultz; and Sherel Goodrich. 1988. Atlas of the Vascular Plants of Utah. Utah Museum of Natural History. http://www.nr.usu.edu/Geography-Department/utgeog/utvatlas/ut-vascatlas.html, accessed September, 2002. Dorn, Robert D. 2001. Vascular plants of Wyoming, Third Edition. Cheyenne, WY: Mountain West Publishing, 412 pp. Fertig, Walter. 2000. State species abstract: Erigeron humilis. Laramie, WY: Wyoming Natural Diversity Database, 2 pp. http://uwadmnweb.uwyo.edu/WYNDD. Handley, Joy; and Scott Laursen. 2002. Sensitive species evaluation: Erigeron humilis. Attached below. Harrington, Harold D. 1954. Manual of the plants of Colorado: For the identification of the ferns and flowering plants of the state. Denver, CO: Sage Books. 666 pp. Hultén, Eric. 1968. Flora of Alaska and neighboring territories. Stanford, CA: Stanford University Press, 1008 pp. Rocky Mountain Herbarium. 1998. Atlas of the vascular plants of Wyoming. http://www.esb.utexas.edu/tchumley/wyomap/atlas.htm, accessed September, 2002. Spackman, Susan; Bill Jennings; Janet Coles; Carol Dawson; Mark Minton; Andrew Kratz; Carol Spurrier; Christopher S. Johnson; and Mike Barry. 1999. Colorado rare plant field guide. http://ndis.nrel.colostate.edu/ndis/rareplants/cover.html, last updated March 1, 1999. Hultén, Eric. 1968. Flora of Alaska and neighboring territories. Stanford, CA: Stanford University Press, 1008 pp, Rocky Mountain Herbarium. 1998. Atlas of the vascular plants of Wyoming. http://www.esb.utexas.edu/tchumley/wyomap/atlas.htm, accessed September, 2002. Weber, William A.; and Ronald C. Wittmann. 2000. Catalog of the Colorado flora: A biodiversity baseline. Boulder, CO: University of Colorado Museum. Revised March 11, 2000. http://www.colorado.edu/CUMUSEUM/research/botany/Catalog/Catalog.htm, downloaded September, 2002. Weber, William A.; and Ronald C. Wittmann. 2001a. Colorado flora: Western slope, Third Edition. Niwot, CO: Colorado Associated University Press. 488 pp. Weber, William A.; and Ronald C. Wittmann. 2001b. Colorado flora: Eastern Slope, Third Edition. Boulder, CO: University Press of Colorado. 521 pp. Welsh, Stanley L.; N. Duane Atwood; Sherel Goodrich; and Larry C. Higgins, Editors. 1993. A Utah flora. Provo, UT: Brigham Young University, 986 pp. Author and date: Barry C. Johnston, Botanist, Grand Mesa-Uncompahgre-Gunnison National Forests, 216 N. Colorado St., Gunnison, CO 81230-2197. (970) 642-4467. [email protected]. Last modified September 26, 2002. 2 SPECIES EVALUATION REGION 2 SENSITIVE SPECIES EVALUATION FORM Species: Erigeron humilis / Low Fleabane (E. uniflorus var unalaschkensis) Criteria Rank Rationale Literature Citations In Wyoming, Low Fleabane occurs in the Beartooth, Bighorn, and Absaroka ranges in Big Horn • Colorado Native Plant Society 1 BD and Park counties on the Bighorn and Shoshone national forests. It is also known from the 1997 Distribution within R2 Arapaho-Roosevelt, White River, and Grand Mesa, Uncompahgre, Gunnison national forests in • Dorn 2001 Colorado, therefore, additional information is needed to determine its status in Region 2. • Evert 1986 Low Fleabane is found on montane granite and limestone cliff faces, talus slopes, and in alpine • Fertig 1997, 1998, 1999, 2000 meadows and tundra. It is often in mossy, moist microsites. It is sporadic in Region 2 at the • Jones and Fertig 1999 southern end of its range. • Lofgren 1956 Confidence in Rank High • Mills and Fertig 1996 • Scott 1997 • USDA Forest Service R2 2001 • University of Wyoming 1998 Low Fleabane is circumpolar species, found in North America south to central Idaho, northwest • Cronquist 1955 2 C Montana, northern Wyoming, and Colorado. In Wyoming, it is known from outside Region 2 in Distribution • Dorn 2001 outside R2 the Wind River and Gros Ventre mountains in Sublette County. Reports from the Medicine Bow • Moseley 1989 Range (Albany County) are probably based on immature specimens of Erigeron melanocephalus. Confidence in Rank High It may be inferred that the bristly pappus is appropriate for wind dispersal across unsuitable • Cronquist 1955 3 CD habitat. Dispersal • Scott 1997 Capability Confidence in Rank High Low Fleabane is known from 9 records in Wyoming, 8 of which are recent and presumed extant • Evert 1986 4 AB (the oldest known record dates from 1955). Three sites have been located since 1990 (most Abundance in • Fertig 1997, 1998, 1999, 2000 R2 recently in 1998). Six locations are on the Shoshone National Forest and one is on the Bighorn • Jones and Fertig 1999 National Forest. Known populations are small in number and occupied area. Surveys in 1996 in • Lofgren 1956 the Beartooth Mountains reported colonies of 10-25 plants. This species is ranked “S2” in • Mills and Fertig 1996 Wyoming and “S1” in Colorado. • NatureServe 2002 Confidence in Rank High • University of Wyoming 1998 • WYNDD 2002 5 D Populations are presumed to be stable at present, although no trend data are available. • - Population Trend in R2 Habitat is presumed to be stable at present, although no trend data are available. • - 6 D Confidence in Rank High Habitat Trend in R2 Threats are not known, but are presumed to be low. Most Wyoming populations of Low • Evert 1986 7 BD Fleabane are in wilderness areas on the Bighorn, Bridger-Teton, and Shoshone National Habitat • Fertig 1997, 1998, 1999, 2000 Vulnerability or Forests. • Jones and Fertig 1999 Modification Confidence in Rank High • Lofgren 1956 • Mills and Fertig 1996 3 SPECIES EVALUATION Species: Erigeron humilis / Low Fleabane (E. uniflorus var unalaschkensis) Criteria Rank Rationale Literature Citations Low Fleabane is a perennial forb. Flowering and fruiting occur from July through August. • Cronquist 1955 8 D Additional information on the species, including life history stages, population structure, Life History and • Fertig 2000 Demographics longevity, mortality, and seed biology, are not available. • Scott 1997 Confidence in Rank High Initial Evaluator(s): Date: March 6, 2002 Joy Handley and Scott Laursen National Forests in the Rocky Mountain Region where species is KNOWN (K) or LIKELY(L)1 to occur: Colorado NF/NG Kansas NF/NG Nebraska NF/NG South Dakota Wyoming NF/NG NF/NG Likely Likely Known Known Known Likely Known Likely Known Likely Arapaho-Roosevelt NF X Cimmaron NG Samuel R.McKelvie NF Black Hills NF Shoshone NF X White River NF X Halsey NF Buffalo Gap NG Bighorn NF X Routt NF Nebraska NF Ft.