ATTACHMENT SS2 REGION 2 SENSITIVE SPECIES EVALUATION FORM Species: Erigeron subtrinervis / Three-nerve Fleabane; There are two varieties of Erigeron subtrinervus present in Region 2 and in Wyoming, E. S. VAR. SUBTRINERVIS and E. S. VAR. CONSPICUUS. Criteria Rank Rationale Literature Citations (subtrinervis/ conspicuus) Region 2 harbors the central portion of E. s. var. subtrinervis’ distribution. It • Dorn 2001 1 C/B occurs widely across the state of Wyoming as well as in Colorado, South Dakota, Distribution • Great Plains Flora Association within R2 and Nebraska. In Wyoming this variety occurs in Black Hills National Forest, 1986 Bighorn National Forest, Medicine Bow National Forest, and Thunder Basin • Hitchcock 1955 National Grassland. • NatureServe 2002 • USDA Forest Service R2 2001 Region 2 harbors the southeastern portion of E. s. var. conspicuus distribution. It • University of Wyoming 1998 occurs in west and central Wyoming, including Bighorn National Forest and Shoshone National Forest. This variety is not present in other Region 2 states. NOTE: The table of species R2 distribution that follows pertains only to this variety as the less common of the two. In Wyoming, E. s. var. subtrinervis is commonly found between 4200-10,000 feet in elevation on limestone outcrops in sagebrush grasslands and shaded forests, such as Pinus ponderosa with Juniperus scopulorum understory, Pseudotsuga menziesii, or Populus tremuloides. These habitats are common within Wyoming’s national forest and national grassland boundaries where many E. s. var. subtrinervis collections have been made, specifically in Bighorn National Forest, Black Hills National Forest, Thunder Basin Grassland, and Medicine Bow National Forest. It is also found on the Oglalla National Grassland of Nebraska. E. s. var. conspicuus is commonly found between 6300-9400 feet in elevation on grassy, rocky slopes with scattered Populus tremuloides, Picea engelmannii, or Pinus flexilis. These habitats are common in Bighorn National Forest and Shoshone National Forest where this variety has been collected. Habitats for both varieties represent a variety of substrates and vegetation types that are discontinuous though widespread on the landscape. Confidence in Rank High USDA-Forest Service R2 Sensitive Species Evaluation Form Page 1 of 4 ATTACHMENT SS2 Species: Erigeron subtrinervis / Three-nerve Fleabane; There are two varieties of Erigeron subtrinervus present in Region 2 and in Wyoming, E. S. VAR. SUBTRINERVIS and E. S. VAR. CONSPICUUS. Criteria Rank Rationale Literature Citations (subtrinervis/ conspicuus) Outside of Region 2, E. s. var. subtrinervis is known to occur from southern • Hitchcock et al. 1994, Part 5 2 B/C Montana and North Dakota south to New Mexico and Nebraska, but is largely Distribution • NatureServe 2002 outside R2 centered in the Rocky Mountain Region 2. E. s. var. conspicuous occurs from British Columbia and Alberta south to Washington, Idaho and Wyoming. Both varieties occur outside of Region 2 in western Wyoming, specifically Teton County. Confidence in Rank High It may be inferred that the bristly pappus is appropriate for wind dispersal across • - 3 D unsuitable habitat. Dispersal Capability Confidence in Rank High E. s. var. subtrinervis is known from more than 40 locations in Wyoming. All but • NatureServe 2002 4 C/B one of these are in Region 2. E. s. var. subtrinervis is ranked “S3” in Wyoming Abundance in • University of Wyoming 1998 R2 and is not tracked. It is not ranked in Colorado, Nebraska or South Dakota. • WYNDD 2002 E. s. var. conspicuous is known from 11 sites in Wyoming, 7 of which are in Region 2. It is ranked “S2” in Wyoming but is not tracked. Confidence in Rank Medium 5 D Not known. • - Population Trend in R2 Confidence in Rank High 6 D Not known. • - Habitat Trend in R2 Confidence in Rank High USDA-Forest Service R2 Sensitive Species Evaluation Form Page 2 of 4 ATTACHMENT SS2 Species: Erigeron subtrinervis / Three-nerve Fleabane; There are two varieties of Erigeron subtrinervus present in Region 2 and in Wyoming, E. S. VAR. SUBTRINERVIS and E. S. VAR. CONSPICUUS. Criteria Rank Rationale Literature Citations (subtrinervis/ conspicuus) Both varieties largely occur on national grasslands and national forests, which • University of Wyoming 1998 7 BD are managed for multiple use. Their habitats might be vulnerable to overgrazing Habitat Vulnerability and timber management though the range of habitats may indicate that there is or limited vulnerability. Modification Confidence in Rank Medium 8 D Three-nerve fleabane flowers mostly from July to August. • Hitchcock 1955 Life History and Life history information on this species, including life history stages, population Demographics structure, longevity, mortality, pollination biology and seed biology, are not available. Confidence in Rank High Initial Evaluator(s): Date: March 22, 2002 Scott Laursen and Bonnie Heidel National Forests in the Rocky Mountain Region where species is KNOWN (K) or LIKELY(L)1 to occur: 1 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. USDA-Forest Service R2 Sensitive Species Evaluation Form Page 3 of 4 ATTACHMENT SS2 Colorado NF/NG Kansas NF/NG Nebraska NF/NG South Dakota Wyoming NF/NG NF/NG y y y y y Known Likel Known Likel Known Likel Known Likel Known Likel Arapaho-Roosevelt NF Cimmaron NG Samuel R.McKelvie NF Black Hills NF Shoshone NF X White River NF Halsey NF Buffalo Gap NG Bighorn NF X Routt NF Nebraska NF Ft. Pierre NG Black Hills NF Grand Mesa, Ogalala NG X Medicine Bow NF Uncompahgre, Gunnison NF San Juan NF Thunder Basin NG Rio Grande NF Pike-San Isabel NF Comanche NG Literature cited Dorn, R.D. 2001. Vascular Plants of Wyoming, third edition. Mountain West Publishing, Cheyenne, WY. Great Plains Flora Association. 1986. Flora of the Great Plains. Univ. Kansas Press, Lawrence, KS. Hitchcock, C.L. 1955. Pt. 5. Compositae, IN: Hitchcock, C.L., A. Cronquist, M. Owenbey, and J.W. Thompson (eds). Vascular Plants of the Pacific Northwest. University of Washington Publications in Biology 17(5): 1-343. NatureServe. 2002. Explorer – an encyclopedia of life. Plant and animal data posted at www.natureserveexplorer.org, Arlington, VA. USDA Forest Service – Region 2. 2001. “Wyoming plant species” evaluation list and criteria provided to Wyoming Natural Diversity Database. Denver, CO. University of Wyoming – Rocky Mountain Herbarium. 1998. Atlas of the Flora of Wyoming. Posted electronically through 1998 at: http://www.esb.utexas.edu/tchumley/wyomap/ and unposted accession information at the Rocky Mountain Herbarium through 2001. Wyoming Natural Diversity Database. 2002. Ongoing documentation of sensitive species distribution, biology, status, and references for the state of Wyoming. University of Wyoming, Laramie. USDA-Forest Service R2 Sensitive Species Evaluation Form Page 4 of 4 .