2011-13910. Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Abronia ammophila, Agrostis rossiae, Astragalus proimanthus, Boechera (Arabis) pusilla,

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of 12-month petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding on a petition to list Abronia ammophila (Yellowstone sand verbena), Agrostis rossiae (Ross' bentgrass), Astragalus proimanthus (precocious milkvetch), Boechera (Arabis) pusilla (Fremont County rockcress or small rockcress), and Penstemon gibbensii (Gibbens' beardtongue) as threatened or endangered, and to designate critical habitat under the Endangered Species Act of 1973, as amended (Act). After review of all available scientific and commercial information, we find that listing A. ammophila, A. rossiae, A. proimanthus, and P. gibbensii is not warranted at this time. However, we ask the public to submit to us any new information that becomes available concerning the threats to A. ammophila, A. rossiae, A. proimanthus, and P. gibbensii or their habitats at any time. After a review of all the available scientific and commercial information, we find that listing B. pusilla as threatened or endangered is warranted. However, currently listing B. pusilla is precluded by higher priority actions to amend the Federal Lists of Endangered and Threatened Wildlife and Plants. Upon publication of this 12-month petition finding, we will add B. pusilla to our candidate species list. We will develop a proposed rule to list B. pusilla as our priorities allow. We will make any determinations on critical habitat during development of the proposed listing rule. In any interim period, we will address the status of the candidate taxon through our annual Candidate Notice of Review.

DATES:

The finding announced in this document was made on June 9, 2011.

ADDRESSES:

This finding is available on the Internet at http://www.regulations.gov at Docket Number FWS-R6-ES-2011-0023. Supporting documentation used in preparing this finding is available for public inspection, by appointment, during normal business hours at the U.S. Fish and Wildlife Service, Wyoming Ecological Services Field Office, 5353 Yellowstone Road, Suite 308A, Cheyenne, WY 82009. Please submit any new information, materials, comments, or questions concerning this finding to the above address.

FOR FURTHER INFORMATION CONTACT:

R. Mark Sattelberg, Field Supervisor, Wyoming Ecological Services Field Office (see ADDRESSES); by telephone at 307-772-2374; or by facsimile at 307-772-2358. If you use a telecommunications device for the deaf (TDD), please call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

Section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.), requires that, for any petition to revise the Federal Lists of Endangered and Threatened Wildlife and Plants that contains substantial scientific or commercial information that listing the species may be warranted, we make a finding within 12 months of the date of receipt of the petition. In this finding, we will determine that the petitioned action is: (1) Not warranted, (2) warranted, or (3) warranted, but the immediate proposal of a regulation implementing the petitioned action is precluded by other pending proposals to determine whether species are threatened or endangered, and expeditious progress is being made to add or remove qualified species from the Federal Lists of Endangered and Threatened Wildlife and Plants. Section 4(b)(3)(C) of the Act requires that we treat a petition for which the requested action is found to be warranted but precluded as though resubmitted on the date of such finding, that is, requiring a subsequent finding to be made within 12 months. We must publish these 12-month findings in the Federal Register.

Previous Federal Actions

Federal action for Agrostis rossiae and Astragalus proimanthus began as a result of section 12 of the original Act, which directed the Secretary of the Smithsonian Institution to prepare a report on plants considered to be endangered, threatened, or extinct in the United States. This report, designated as House Document No. 94-51, was presented to Congress on January 9, 1975. That document lists A. rossiae as a threatened species and A. proimanthus as an endangered species (House Document 94-51, pp. 57, 90, 163). On July 1, 1975, we published a notice in the Federal Register (40 FR 27823) accepting the Smithsonian Institution report as a petition within the context of section 4(c)(2) (petition provisions are now found in section 4(b)(3) of the Act), and giving notice of the Service's intention to review the status of the plant taxa listed therein.

As a result of that review, we published a proposed rule on June 16, 1976, in the Federal Register (41 FR 24523) to determine endangered status pursuant to section 4 of the Act for approximately 1,700 vascular plant taxa, including Astragalus proimanthus. This list of plant taxa was assembled based on comments and data received by the Smithsonian Institution and the Service in response to House Document No. 94-51 and the July 1, 1975, Federal Register publication. General comments received in response to the 1976 proposal are summarized in an April 26, 1978, Federal Register publication (43 FR 17909). In 1978, amendments to section 4(f)(5) of the Act required that all proposals over 2 years old be withdrawn. However, proposals already over 2 years old were given a 1-year grace period. On December 10, 1979, we published a notice in the Federal Register (44 FR 70796) withdrawing the portion of the June 16, 1976, proposal that had not been made final. This removed both A. proimanthus and Agrostis rossiae from proposed status, but retained both species as candidate plant taxa that “may qualify for listing under the Act.”

On December 15, 1980, we published a current list of those plant taxa native to the United States being considered for listing under the Act; this identified both Agrostis rossiae and Astragalus proimanthus as category 1 taxa (45 FR 82480). The Service defined category 1 taxa as a taxonomic group for which we presently had sufficient information on hand to support the biological appropriateness of these taxa being listed as threatened or endangered species (45 FR 82480). On November 28, 1983, A. rossiae was lowered to a category 2 taxon “currently under review,” whereas A. proimanthus was moved to the “taxa no longer under review” list, and given a 3C rank, indicating the species was more abundant or widespread than previously believed or not subjected to any identifiable threat (48 FR 53640). We defined category 2 taxa as those for which we had information at that time that indicated proposing to list was possibly appropriate, but for which substantial data on biological vulnerability and threat(s) was not currently known or on file to support proposed rules. Boechera (formerly Arabis) pusilla and Penstemon gibbensii were added as category 2 taxa during the same review (48 FR 53640). These four species retained the same ranking for the subsequent review on September 27, 1985 (50 FR 39526). The February 21, 1990, list kept A. rossiae, B. pusilla, and P. gibbensii as category 2 taxa, and reverted A. proimanthus back to a category 2 taxon (55 FR 6184).

The September 30, 1993, review changed the status of Boechera pusilla to a category 1 species (58 FR 51144). This review added a “status trend” column. Each species was identified as increasing (I), stable (S), declining (D), or unknown (U). The 1993 review added Abronia ammophila and assigned it a 2U rank, moved Boechera pusilla up to a 1D rank, and listed Agrostis rossiae as 2U, Astragalus proimanthus as 2S, and Penstemon gibbensii as 2U (58 FR 51144).

On February 28, 1996, we proposed discontinuing the designation of category 2 species as candidates due to the lack of sufficient information to justify issuance of a proposed rule (61 FR 7596). This proposal included eliminating candidate status for four of the five species addressed in this finding; only Boechera pusilla was proposed to remain a candidate (61 FR 7596). This policy change was finalized on December 5, 1996, stating that the listing of category 2 species was not needed because of other lists already maintained by other entities such as Federal and State agencies (61 FR 64481).

On September 19, 1997, we published a notice of review that retained Boechera pusilla as a candidate species (62 FR 49398). However, on October 25, 1999, we published a notice of review that indicated our intent to remove several species, including B. pusilla, from the list of candidate species because evidence suggested that these taxa were either more abundant than previously believed or that the taxa were not subject to the degree of threats sufficient to warrant continuance of candidate status, issuance of a proposed listing, or a final listing (64 FR 57534). The change of status for B. pusilla was finalized on October 20, 2000, on the basis that regulatory mechanisms and changes to management of the associated land reduced or eliminated the threats facing B. pusilla and ensured the survival and conservation of this species (65 FR 63044).

On July 30, 2007, we received a formal petition dated July 24, 2007, from Forest Guardians (now WildEarth Guardians), requesting that we: (1) Consider all full species in our Mountain-Prairie Region ranked as G1 or G1G2 by the organization NatureServe, except those that are currently listed, proposed for listing, or candidates for listing; and (2) list each species as either threatened or endangered. The petition identified 206 species as petitioned entities, including the 5 species we address in this status review. A species ranking of G1 is defined as a species that is critically imperiled across its entire range (or global range) (NatureServe 2010b, p. 3). A ranking of G1G2 means the species is either ranked as a G1 or a G2 species, with G2 defined as imperiled across its entire range (NatureServe 2010b, pp. 3-4). The petition incorporated all analysis, references, and documentation provided by NatureServe in its online database at http://www.natureserve.org/​ into the petition. The petition clearly identified itself as a petition and included the identification information, as required in 50 CFR 424.14(a). We sent a letter to the petitioners, dated August 24, 2007, acknowledging receipt of the petition and stating that, based on preliminary review, we found no compelling evidence to support an emergency listing for any of the species covered by the petition.

On March 19, 2008, WildEarth Guardians filed a complaint (1:08-CV-472-CKK) indicating that the Service failed to comply with its mandatory duty to make a preliminary 90-day finding on their two multiple-species petitions—one for mountain-prairie species and one for southwest species. We subsequently published two initial 90-day findings on January 6, 2009 (74 FR 419), and February 5, 2009 (74 FR 6122). The February 5, 2009, finding determined that there was not substantial scientific or commercial information indicating that listing 165 of the 206 petitioned species in the mountain-prairie region may be warranted (74 FR 6122). Two additional species were evaluated in a January 6, 2009, 90-day finding (74 FR 419), and no determination was made on whether substantial information had been presented on the remaining 39 species included in the petition (74 FR 6122). The 5 species covered in this 12-month finding were among the remaining 39 species. An additional species was determined to qualify for candidate status (73 FR 75175; December 10, 2008). On March 13, 2009, the Service and WildEarth Guardians filed a stipulated settlement in the District of Columbia Court, agreeing that the Service would submit to the Federal Register a finding as to whether WildEarth Guardians' petitions present substantial information indicating that the petitioned actions may be warranted for the remaining 38 mountain-prairie species by August 9, 2009.

On June 18, 2008, we received a petition from WildEarth Guardians dated June 12, 2008, to emergency list 32 species under the Administrative Procedure Act and the Endangered Species Act. Of those 32 species, 11 were included in the July 24, 2007, petition to be listed on a non-emergency basis. Although the Act does not provide for a petition process for an interested person to seek to have a species emergency listed, section 4(b)(7) of the Act authorizes the Service to issue emergency regulations to temporarily list a species. In a letter dated July 25, 2008, we stated that the information provided in both the 2007 and 2008 petitions and in our files did not indicate that an emergency situation existed for any of the 11 species. The Service's decisions whether to exercise its authority to issue emergency regulations to temporarily list a species are not judicially reviewable. See Fund for Animals v. Hogan, 428 F.3d 1059 (DC Cir. 2005).

On August 18, 2009, we published a notice of 90-day finding (74 FR 41649) on the remaining 38 species from the petition to list 206 species in the mountain-prairie region of the United States as threatened or endangered under the Act. We found that the petition presented substantial scientific and commercial information for 29 of the 38 species, indicating that listing may be warranted for those species. The 5 species we address in this 12-month finding were included within these 29 species. We also opened a 60-day public comment period to allow all interested parties an opportunity to provide information on the status of the 29 species (74 FR 41649). The public comment period closed on October 19, 2009. We received 224 public comments. Of these, 38 specifically addressed Abronia ammophila, Agrostis rossiae, Astragalus proimanthus, Boechera pusilla, and Penstemon gibbensii. All information received has been carefully considered in this finding. This notice constitutes the 12-month finding on 5 of the 206 species identified in WildEarth Guardians' petition dated July 24, 2007, to list Abronia ammophila, Agrostis rossiae, Astragalus proimanthus, Boechera pusilla, and Penstemon gibbensii as threatened or endangered.

Summary of Procedures for Determining the Listing Status of Species

Review of Status Based on Five Factors

Section 4 of the Act (16 U.S.C. 1533) and implementing regulations (50 CFR part 424) set forth procedures for adding species to, removing species from, or reclassifying species on the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, a species may be determined to be endangered or threatened based on any of the following five factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

In making these findings, information pertaining to each species in relation to the five factors provided in section 4(a)(1) of the Act is discussed below. In considering what factors might constitute threats to a species, we must look beyond the exposure of the species to a particular factor to evaluate whether the species may respond to the factor in a way that causes actual impacts to the species. If there is exposure to a factor and the species responds negatively, the factor may be a threat, and during the status review, we attempt to determine how significant a threat it is. The threat is significant if it drives or contributes to the risk of extinction of the species such that the species warrants listing as endangered or threatened as those terms are defined by the Act. However, the identification of factors that could impact a species negatively may not be sufficient to compel a finding that the species warrants listing. The information must include evidence sufficient to suggest that the potential threat has the capacity (i.e., it should be of sufficient magnitude and extent) to affect the species' status such that it meets the definition of endangered or threatened under the Act.

Findings

Distinct Population Segments

After considering the five factors, we assess whether each species is threatened or endangered throughout all of its range. Generally, we next consider in our findings whether a distinct vertebrate population segment (DPS) or any significant portion of the species' range meets the definition of endangered or is likely to become endangered in the foreseeable future (threatened). Section 3(16) of the Act defines a species to include only a vertebrate species as a DPS. Therefore, the Service's Policy Regarding the Recognition of Distinct Vertebrate Population Segments Under the Endangered Species Act (DPS Policy) (61 FR 4722; February 7, 1996) is not applicable to plants and no population segments under the review could qualify as DPSs under the Act. Although the Service's DPS Policy is not applicable to plants, we do determine in our findings whether a plant species is threatened or endangered in a significant portion of its range.

Significant Portion of the Range

In determining whether a species is threatened or endangered in a significant portion of its range, we first identify any portions of the range of the species that warrant further consideration. The range of a species can theoretically be divided into portions an infinite number of ways. However, there is no purpose to analyzing portions of the range that are not reasonably likely to be both (1) significant and (2) threatened or endangered. To identify only those portions that warrant further consideration, we determine whether there is substantial information indicating that: (1) The portions may be significant, and (2) the species may be in danger of extinction there or likely to become so within the foreseeable future. In practice, a key part of this analysis is whether the threats are geographically concentrated in some way. If the threats to the species are essentially uniform throughout its range, no portion is likely to warrant further consideration. Moreover, if any concentration of threats applies only to portions of the species' range that are not significant, such portions will not warrant further consideration.

If we identify portions that warrant further consideration, we then determine whether the species is threatened or endangered in these portions of its range. Depending on the biology of the species, its range, and the threats it faces, the Service may address either the significance question or the status question first. Thus, if the Service considers significance first and determines that a portion of the range is not significant, the Service need not determine whether the species is threatened or endangered there. Likewise, if the Service considers status first and determines that the species is not threatened or endangered in a portion of its range, the Service need not determine if that portion is significant. However, if the Service determines that both a portion of the range of a species is significant and the species is threatened or endangered there, the Service will specify that portion of the range as threatened or endangered under section 4(c)(1) of the ESA.

Evaluation of the Status of Each of the Five Plant Species

For each of the five species, we provide a description of the species and its life-history and habitat, an evaluation of listing factors for that species, and our finding that the petitioned action is warranted or not for that species. We follow these descriptions, evaluations, and findings with a discussion of the priority and progress of our listing actions.

Species Information for Abronia ammophila

Species Description

Abronia ammophila is a low-growing, mat-forming perennial herb (Clark et al. 1989, p. 7; Fertig 1994, unpaginated; (National Park Service (NPS) 1999b, p. 3; Fertig 2000b, unpaginated; Saunders and Sipes 2006, p. 76). A. ammophila is a highly restricted endemic (occurring only in one location or region) to the Yellowstone Plateau (NPS 1999a, p. 1). In addition to the common name of Yellowstone sand verbena, A. ammophila has been called Tweedy's sand verbena (Clark et al. 1989, p. 7; Marriott 1993, p. 1) and Wyoming sand verbena (Integrated Taxonomic Information System 2010a, unpaginated).

Abronia ammophila has a large taproot (primary root that grows vertically downward, not highly branched) that can be over 0.5 meter (m) (1.6 feet (ft)) in length, which helps the plant root into the loose sand (Whipple 1999, p. 3; Whipple 2002, p. 257; Saunders and Sipes 2004, p. 9). Its stems can grow up to 2 to 4 decimeters (dm) (0.66 to 1.31 ft) in length; however, this plant is only 2.5 to 10.2 centimeters (cm) (1 to 4 inches (in.)) tall (Rydberg 1900, p. 137; Galloway 1975, p. 344; Fertig 1994, unpaginated; NPS 1999b, p. 3; Fertig 2000b, unpaginated; NPS 2000, unpaginated). A. ammophila is covered by sticky glands, which result in the plants being covered with sand (Coulter and Nelson 1909, p. 175; NPS 1999b, p. 3; NPS 2000, unpaginated; Whipple 2002, pp. 257-258; Saunders and Sipes 2006, p. 76). The leaf blades are succulent (fleshy) and oval or diamond-shaped with smooth edges (Fertig 1994, unpaginated; NPS 1999b, p. 3).

The flowers of Abronia ammophila are whitish to light pink or light green and grow in a capitulum (head-like group of flowers) typically containing 4 to 21 flowers (Saunders and Sipes 2006, p. 79). The flowers are hermaphroditic (possessing both male and female reproductive organs) (Saunders and Sipes 2004, p. 9; 2006, p. 76). As with other members of the Nyctaginaceae (the Four O'Clock) family, A. ammophila lacks true petals (Saunders and Sipes 2004, p. 9; 2006, p. 76).

Discovery and Taxonomy

Frank Tweedy made the first collection of Abronia ammophila in 1885; however, he labeled it as Abronia villosa (desert sand verbena). The collection was from the sandy beaches on the north side of Yellowstone Lake at the mouth of Pelican Creek (Tweedy 1886, p. 59). A. villosa is a common purple-flowered species of the American southwest (Whipple 2002, p. 256). In 1900, Per Axel Rydberg determined that Tweedy's sample was sufficiently different from other Abronia to warrant recognition as a unique species; he named it Abronia arenaria (coastal sand verbena) (NPS 1999b, p. 2; Whipple 1999, p. 3; 2002, p. 256). However, the name A. arenaria had previously been used (NPS 1999b, p. 2; Whipple 1999, p. 2; 2002, p. 256). E.L. Greene proposed the name A. ammophila for the Yellowstone sand verbena species (Greene 1900 as cited in Whipple 2002, p. 256).

The name Abronia ammophila was formally recognized (Coulter and Nelson 1909, p. 175); however, midway through the 20th century it was combined with Abronia fragrans (snowball sand verbena), a widespread western species (Hitchcock et al. 1964 and Despain 1975 as cited in Whipple 2002, p. 257). In 1975, a study of the Abronia genus determined that the Yellowstone species was unique (Galloway 1975, p. 344; NPS 1999b, p. 3; Whipple 2002, p. 257). Plant material collected from scrub communities of sandy hills near Big Piney, Sublette County, Wyoming, also was included under A. ammophila (Galloway 1975, p. 344, NPS 1999b, p. 3; Whipple 2002, p. 257). Further examination revealed that the specimens from Sublette County are actually Abronia mellifera (white sand verbena) (Marriott 1993, pp. 6, 9; Fertig 1994, unpaginated).

Abronia ammophila is a member of the New World plant family Nyctaginaceae that typically lives in warmer climates, such as deserts and tropical areas (NPS 2000, unpaginated). The genus Abronia contains approximately 20 to 30 species (NPS 1999b, p. 2, Flora of North America 2010a, unpaginated). Most Abronia occur in the western United States and Mexico, but some extend into southern Canada and east into the Great Plains and Texas (NPS 1999b, p. 2). A. ammophila is similar to Abronia mellifera (Fertig 1994, unpaginated) and Abronia fragrans (Flora of North America 2010, unpaginated). We recognize A. ammophila as a valid species and a listable entity.

Biology and Life History

Abronia ammophila starts to flower by the middle of June and continues producing flowers until a frost occurs that kills its aboveground parts, usually in late August or early September (NPS 1999b, p. 6; Whipple 1999, p. 3; NPS 2000, unpaginated; Whipple 2002, p. 258). This extended blooming period is unusual in comparison to other plants in Yellowstone National Park (YNP) (Whipple 1999, p. 3). Additionally, unlike many of its associated species, A. ammophila continues to flower vigorously even after setting fruit (NPS 1999b, p. 6; Whipple 2002, p. 258).

Abronia ammophila is visited by several orders of insects (Saunders and Sipes 2004, p. 10; 2006, p. 80). The most frequent visitors to A. ammophila are lepidopterans (butterflies and moths) (Saunders and Sipes 2004, p. 10; 2006, p. 80). Even though Abronia ammophila is visited by a diverse range of pollinators, the total number of pollinator visitations is extremely low (Saunders and Sipes 2006, p. 81). The low level of pollinator visits may be offset by A. ammophila exhibiting a mixed-mating system (Saunders and Sipes 2004, pp. 6, 10, 12; 2006, p. 82). In addition to cross-pollination facilitated by pollinators, A. ammophila is able to self-pollinate with or without a pollen vector (Saunders and Sipes 2004, pp. 6, 10, 12; 2006, pp. 80-82; Whipple 2010b, pers. comm.). Self-pollination is highly likely due to the floral morphology (the structure of the flower) and the functional phenology (life cycle) of A. ammophila (Saunders and Sipes 2006, p. 81).

Abronia ammophila is capable of producing large numbers of flowers (Saunders and Sipes 2004, p. 13). Seed dispersal mechanisms of Abronia ammophila have not been extensively studied. Primary seed dispersal appears to occur beneath the parent plant (Saunders and Sipes 2006, p. 79). Seeds also accumulate in depressions of the sand, where the wind has blown them (NPS 1999b, p. 6; Whipple 2002, p. 258). The sticky surface of the seeds may facilitate dispersal, for example on the feet of waterfowl (NPS 1999b, pp. 6-7; Whipple 2002, p. 258). Water also may facilitate dispersal (Saunders and Sipes 2006, p. 79). As A. ammophila occurs in locations that are not located adjacent to each other, there appears to be an effective method of seed dispersal (NPS 1999b, pp. 6-7; Whipple 2002, p. 258). However, the longevity of A. ammophila seeds in the seed bank in unknown (NPS 1999b, p. 7; Whipple 2002, p. 258).

Habitat

Abronia ammophila is endemic to YNP, within Park and Teton Counties of Wyoming (Whipple 2002, p. 256; Fertig 2000b, unpaginated; Saunders and Sipes 2006, p. 76). Specifically, A. ammophila occurs around Yellowstone Lake typically within 40 m (131.2 ft) of the shoreline (NPS 1999b, p. 5; Whipple 1999, p. 3; Fertig 2000b, unpaginated; Whipple 2002, p. 262). The plant has been found up to 60 m (196.9 ft) inland and up to approximately 10 m (32.8 ft) above the high-water line (NPS 1999b, p. 5; Whipple 1999, p. 3; Fertig 2000b, unpaginated; Whipple 2002, p. 262). A. ammophila generally occurs above the high-water mark; no plants grow in areas that are regularly inundated (NPS 1999b, p. 5; Whipple 1999, p. 3; 2002, p. 262). Yellowstone Lake is a high-elevation (2,360 m (7,742 ft)), freshwater lake that was formed by volcanic activity (Pierce et al. 2007, pp. 131-132; NPS 2006a, unpaginated). The lake level was originally 61 m (200 ft) higher than its present level, and the level is not entirely stable (Pierce et al. 2007, pp. 131-132; NPS 2006a, unpaginated). A. ammophila appears to be able to adapt to the continually changing boundaries of its habitat as defined by Yellowstone Lake's fluctuations.

Occurring between the area of beach affected by wave action and the more densely vegetated areas inland, Abronia ammophila prefers open, sunny, sparsely vegetated sites (NPS 1999b, p. 5; Whipple 2002, p. 262; Saunders and Sipes 2006, p. 77). Associated vegetative species include Phacelia hastata (silver-leaf scorpion-weed), Rumex venosus (veiny dock), Polemonium pulcherrimum (Jacob's-ladder), and Lupinus argenteus (silvery lupine) (NPS 1999b, p. 5; Whipple 2002, p. 262; Saunders and Sipes 2006, p. 77). A. ammophila loses its competitive advantage on more stable soils or in areas where Artemisia tridentata (big sagebrush) or Eriogonum umbellatum (sulfur flower buckwheat) occur (Whipple 2002, p. 262; Saunders and Sipes 2006, p. 77).

Abronia ammophila occurs at four locations around Yellowstone Lake; these locations are identified as North Shore, Rock Point, Pumice Point, and South Arm (NPS 1999a, pp. 3-6; NPS 1999b, pp. 4-5; Whipple 2002, p. 262). These populations cover an area of 0.6 hectares (ha) (1.48 acres (ac)) (Whipple 2011, pers. comm.). The populations all occur in loose, unconsolidated (loosely arranged) sand with a minimal amount of fines (powdered material), gravel, or organic matter (NPS 1999b, p. 5; Whipple 2002, p. 262; Saunders and Sipes 2006, p. 77). All sites are located on beach sand except the Pumice Point site, which occurs on black sand (NPS 1999b, p. 5; Whipple 2002, p. 262). Some of the populations occur in horseshoe-shaped, sandy depressions (blowouts) (NPS 1999a, p. 3; 1999b, p. 5; Whipple 2002, p. 262; Saunders and Sipes 2006, p. 77). Additionally, the largest subpopulation in the North Shore area—the “Thermal” site—is located adjacent to a small thermal barren (area where no vegetation grows) (NPS 1999a, p. 6; NPS 1999b, p. 6). This area hosts an extremely dense population of Abronia ammophila with some of the largest individuals (NPS 1999b, p. 6). A. ammophila is able to coexist with thermal influences; however, most of the populations grow on ground that is not thermally influenced (NPS 1999a, p. 6).

Distribution and Abundance

Herbarium records show that Abronia ammophila was previously more widely distributed along the northern shore of Yellowstone Lake (NPS 1999b, p. 9; Whipple 2002, p. 258). Locations such as 0.40 kilometer (km) (0.25 mile (mi)) west of the mouth of Pelican Creek and several locations near the current Fishing Bridge development have been recorded as collection locations of A. ammophila (NPS 1999b, p. 9; Whipple 2002, pp. 258-259). Many additional areas of the northern shoreline provide suitable habitat for A. ammophila, such as west of Pelican Creek to the outlet of the Yellowstone River and Mary Bay (NPS 1999b, p. 9; Whipple 2002, p. 259; Whipple 2010a, pers. comm.). Construction of the East Entrance Road and the Fishing Bridge campground, an area that was near the current parking area for the Fishing Bridge Museum, as well as higher human use may have extirpated populations of A. ammophila in these areas (NPS 1999b, pp. 8-9; Whipple 2002, pp. 258-259; Whipple 2010a, pers. comm.).

Table 1 below presents available information regarding the four populations of Abronia ammophila. The 1998-1999 survey was a rigorous population count (NPS 1999a, entire). The other years were generally estimates, except for some of the smaller populations where an exact count was easily obtained (Correy 2009, entire; Whipple 2010d, pers. comm.).

Table 1—Population Estimates of Abronia ammophila

Population (year of discovery)	Estimated numbers (year)
North Shore (prior to 1998)	Approx. 1,000 (early 1990s). 7,978 (1998-1999) rigorous count. Approx. 3,600 (2010).
Rock Point (1998)	325 (1998). 120 (2009).
Pumice Point (1998)	22 (1998). 1 (2001). 5 (2009). 24 (2010).
South Arm (1998)	1 (1998). 3 (2005). 2 (2010).
Totals	1,000 (early 1990s) (only North Shore known). 8,326 (1998-1999) rigorous count. 2,728 (2009) estimate. 3,626 (2010) estimate.
References: NPS 1999a, Appendix A; Corry 2009, Table 1; Whipple 2002, p. 259; 2010d pers. comm.

The majority of Abronia ammophila is found in the North Shore population scattered along a 2.41-km (1.5-mi) stretch of beach on the northern shoreline of Yellowstone Lake between the mouth of Pelican Creek and Storm Point (NPS 1999a, p. 3; 1999b, p. 4; Correy 2009, p. 2). This population contains 95 percent or more of all A. ammophila (NPS 1999a, pp. 2, Appendix A; Whipple 2002, p. 264; Correy 2009, p. 4). Prior to surveys conducted between 1995 and 1999, the North Shore population of A. ammophila was the only known population (NPS 1999a, p. 3; Correy 2009, p. 2). Of the additionally discovered sites, two are located on the west shore of Yellowstone Lake: One at Rock Point, and one at a picnic area 1.6 km (1 mi) west of Pumice Point (NPS 1999a, p. 5; NPS 1999b, p. 4). Additionally, a single plant was found during surveys on the east shore of the South Arm (NPS 1999a, p. 5). Not all suitable habitat within YNP has been surveyed (NPS 1999a, pp. 6-7).

Casual surveys of the North Shore area in the early 1990s estimated the population to be around 1,000 plants (Correy 2009, pp. 1-2), with the majority of the plants of a large-size class representing mature, older plants (NPS 1999a, p. 1; 1999b, p. 7). No seedlings were observed (NPS 1999b, p. 7). Extensive surveys during the 1998-1999 field seasons conservatively estimated the North Shore population to consist of 7,978 Abronia ammophila plants, with 45 percent of the population represented by young recruitment within the prior 2 years (recruit and medium class plants) (NPS 1999a, p. 1). The record high lake levels of 1996 and 1997 appeared to improve the habitat conditions for A. ammophila by eroding the southern edge of the stabilized sand along the northern shoreline (NPS 1999b, p. 7; Whipple 2002, p. 265). Although this erosion washed away part of the existing habitat, it also improved conditions for recruitment of seedlings (NPS 1999b, p. 7; Whipple 2002, p. 265).

During the 2009-2010 field season, surveys of the North Shore population yielded an approximate count of 3,600 A. ammophila plants (Correy 2009, p. 3; Whipple 2010d, pers. comm.; Whipple 2011, pers. comm.). The North Shore population can be split into four subpopulations (Correy 2009, p. 2). Two of these subpopulations had comparable population counts during both the 1998-1999 survey and the 2009-2010 estimate (Correy 2009, pp. 3-4). The remaining two subpopulations, the Thermal and Long Skinny groups, had decreased in both total area populated and total number of plants (Correy 2009, p. 5). The central portion of the Thermal group is now bare or mostly bare sand due to increased ground temperatures (due to changes within the Yellowstone geothermal basin), ground subsidence, increased scouring during storms, or a combination of such factors (Correy 2009, p. 5). The Long Skinny group also may have been affected by increased ground temperatures, particularly on the western end; furthermore, some of the habitat may have eroded (Correy 2009, p. 5). Additional factors potentially affecting the low population count include many years of drought (Whipple 2002, p. 265; Correy 2009, pp. 5-6) and lack of rigorous survey methods (Correy 2009, pp. 5-6).

The Rock Point and Pumice Point Abronia ammophila populations were accurately counted in 1998 and 2009 (Correy 2009, Table 1). In 1998, the Rock Point population consisted of 324 individual plants; the 2009 survey counted 120 individual plants (NPS 1999a, p. 6; Correy 2009, Table 1). An area of Rock Point surveyed in 1998 had no A. ammophila in June, but contained many medium-sized plants later in the summer (NPS 1999a, p. 6). The Pumice Point population consisted of 22 plants in 1998, whereas only 5 were counted in 2009 (NPS 1999a, p. 6; Correy 2009, Table 1). In 1998, the Pumice Point population contained a higher percentage of large (diameter greater than or equal to 5 up to 30 cm (2 up to 11.8 in.)) and very large (diameter greater than or equal to 30 cm (11.8 in.)) plants when compared to the North Shore population distribution (NPS 1999a, p. 6). Additionally, the Pumice Point population contained 24 plants in the 2010 field survey (Whipple 2010e, pers. comm.), which is comparable to the 1998 population count.

The South Arm population contained only one large Abronia ammophila plant when it was discovered in 1998 (NPS 1999a, p. 6). When this site was revisited in 2005, the large individual found in 1998 was no longer present, but three small A. ammophila plants were present (Correy 2009, p. 2). Additionally, during the 2010 field survey, this population consisted of two plants (Whipple 2010e, pers. comm.).

Dead and dying plants were counted during the 1998-1999 field surveys. Dead and dying Abronia ammophila plants accounted for 1.3 percent of the total population (NPS 1999a, Appendix A). Of the dead A. ammophila plants, many were large individuals; however, some were failed seedlings (NPS 1999b, p. 7). The majority of dead and dying plants did not display obvious causes of mortality; they were interspersed throughout the communities (NPS 1999b, p. 7). Additionally, stressed A. ammophila plants are able to recover and put out new growth later in the season (NPS 1999b, p. 7).

The Wyoming Natural Diversity Database (WNDD) has designated Abronia ammophila as a plant species of concern with ranks of G1 and S1 (Heidel 2007, p. 1). This designation indicates that A. ammophila is considered to be critically imperiled because of extreme rarity (i.e., often less than five occurrences (a location where a plant or plants has been recorded)) or because some factor makes it highly vulnerable to extinction both at the global and State level; however, this ranking does not grant A. ammophila any special status under State legislation (WNDD 2009, unpaginated; WNDD 2010, unpaginated). Since A. ammophila is endemic to Wyoming, the Wyoming occurrences encompass the entire global range. Additionally, YNP considers A. ammophila to be a sensitive species of concern; therefore, it evaluates effects to this species in conjunction with any project or action that has the potential to affect the plant (Whipple 2011, pers. comm.).

Trends

Natural fluctuations in the Abronia ammophila population from year to year or even within a season are not understood (Correy 2009, p. 6). From the first population estimates of the North Shore population in the early 1990s to the more rigorous survey conducted in 1998-1999, there was extensive recruitment and the A. ammophila population increased approximately 87 percent (NPS 1999a, p. 1; Correy 2009, pp. 6, Table 1). Notably, 1996 and 1997 had high precipitation, with resultant high lake levels (NPS 1999a, p. 2). The 1998-1999 surveys recorded approximately 20 percent of the population to be seedlings or recruit size class (NPS 1999a, Appendix A). The 2009 population estimate of the North Shore populations shows a decrease from the 1998-1999 survey (Correy 2009, Table 1). However, the 1998-1999 survey was an exact count, whereas the 2009 was an estimate. Additionally, the subsequent 2010 population estimate shows a slight increase in the population size compared to the 2009 population estimate (Whipple 2010e, pers. comm.). Hypotheses for population fluctuations are changing thermal activity of the underlying area, ground subsidence, changing precipitation levels, and human and animal activity (Correy 2009, pp. 5-6). The A. ammophila population seems to be stable within the parameters of a population that lives in an unstable habitat that fluctuates with wave action and weather (Whipple 2010a, pers. comm.).

Five Factor Evaluation for Abronia ammophila

Information pertaining to Abronia ammophila in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

Potential factors that may affect the habitat or range of Abronia ammophila are discussed in this section, including: (1) Development, (2) trampling, (3) nonnative invasive plants, (4) climate change, and (5) drought.

Development

Abronia ammophila occurs entirely inside YNP, which limits potential threats to its habitat. By statute, regulation, and policy, YNP conserves wildlife and habitat; preserves and maintains biological processes, ecosystem components, and ecological integrity; controls invasive plants; and protects and monitors populations of sensitive plants and animals (See Yellowstone National Park under Factor D. The Inadequacy of Existing Regulatory Mechanisms in this Five Factor Evaluation for Abronia ammophila section). YNP was established prior to the States in which it is located (Mazzu 2010, pers. comm.; Whipple 2010e, pers. comm.). This means that YNP owns not only the land, but also the mineral rights; therefore, energy development is not a threat (Mazzu 2010, pers. comm.; Whipple 2010e, pers. comm.). Construction of new roads, trails, or structures within YNP is rare, with reconstruction of existing features occurring occasionally. When new construction or reconstruction occurs in areas where there are sensitive species, YNP analyzes and carries out construction in a manner that minimizes adverse effects. A. ammophila populations are located a sufficient distance from roads; therefore, road reconstruction does not impact any of the A. ammophila populations (Whipple 2010e, pers. comm.).

As noted above (see Distribution and Abundance), Abronia ammophila has been extirpated in some areas in which there is no longer habitat due to the construction of roads or structures. However, the construction in these areas occurred prior to YNP identifying A. ammophila as a species of conservation concern. Now, when new construction or reconstruction occurs, YNP analyzes and carries out construction in a manner that avoids adverse effects to sensitive species. Additionally, projects must be accompanied by a Resource Compliance Checklist that requires the evaluation of any potential impacts to resources including rare plants; if there are impacts, mitigation measures are developed (Schneider 2010, pers. comm.). The majority of YNP remains undeveloped, and we have no information that this will change; therefore, we do not consider development to be a threat to the species now or in the foreseeable future.

Trampling

Trampling of Abronia ammophila, by both humans and wildlife, is a potential concern at most sites (Whipple 2010a, pers. comm.). The Abronia genus is vulnerable to disturbance by trampling (NPS 1999b, p. 8; Whipple 2010e, pers. comm.). Trampling is frequently indicated as a threat to A. ammophila (e.g., NPS 1999a; 1999b); however, studies that seek to document trampling indicate that there is very little foot traffic actually impacting the populations of A. ammophila (NPS 1999a, pp. 2, 5).

The North Shore population is located in one of the least visited portions of the north side of Yellowstone Lake's shoreline (NPS 1999b, p. 8). A large wetland restricts access to this site from the west (NPS 1999b, p. 8). The Storm Point Trail approaches the east end of the North Shore population, and visitors occasionally walk down the beach toward this population (NPS 1999b, p. 8). The YNP plans to install a sign just past the Storm Point Trail requesting that visitors remain near the water and avoid sensitive vegetation areas (Schneider 2010, pers. comm.).

The Pelican Creek Nature Trail is also near the North Shore population (Schneider 2010, pers. comm.). No plants currently occur in this area; however, it is historical habitat (Whipple 2010a, pers. comm.; Schneider 2010, pers. comm.). YNP is currently considering conservation measures, including closing all or part of this trail to protect the potential habitat (Whipple 2010a, pers. comm.; Schneider 2010, pers. comm.). A final decision, on this trail, has not been made at this time (Whipple 2011, pers. comm.).

The Pumice Point population of Abronia ammophila is located near an unmarked picnic area; the plants are located within 10 m (32.8 ft) of the picnic tables (NPS 1999b, p. 8). This area is currently unsigned (not marked as a picnic area from the main road), and the entrance is inconspicuous (Whipple 2010c, pers. comm.). Additionally, the A. ammophila in this area may be benefiting from the disturbance; if foot traffic did not occur, the area might be more densely vegetated and not available as habitat for A. ammophila (NPS 1999b, p. 8; Whipple 2010c, pers. comm.).

The two remaining populations are in areas with little visitation (NPS 1999b, p. 8). The Rock Point population is approximately a half-hour walk from the closest access point (Whipple 2010c, pers. comm.). The South Arm population is accessible by boat, with a backcountry campsite located about 200 m (656.2 ft) from the population (Whipple 2010c, pers. comm.). This backcountry campsite has no trail access (Whipple 2010c, pers. comm.).

YNP has received approximately 3 million visitors a year for the past 20 years; visitation was over 3 million for 11 of those years (NPS 2010a, unpaginated). From January to September of 2010, YNP received 3.4 million visitors, an increase of 8.7 percent over the previous year (NPS 2010b, unpaginated). Even with increases to visitation, we have no information indicating that the number of visitors correlates with increased trampling of Abronia ammophila populations to a level that poses a threat to the species.

Wildlife trampling, particularly by ungulates, is occasionally indicated as a concern (Whipple 2010a, pers. comm.) We believe that these anecdotal observations do not add up to routine impacts on a scale that would cause the species to be threatened or endangered. Additionally, we believe that trampling by wildlife represents a natural ecological interaction in YNP that the species would have evolved with and poses no threat to long-term persistence.

In summary, the populations of Abronia ammophila are located in areas of YNP that do not receive the bulk of visitor traffic. When surveys have attempted to document trampling by humans, observers had determined that the impact is minor. We have only anecdotal evidence of wildlife trampling. Therefore, we have no information indicating that trampling by either humans or wildlife is a threat to the species now or in the foreseeable future.

Nonnative Invasive Plants

After habitat loss, the spread of nonnative invasive species is considered the second largest threat to imperiled plants in the United States (Wilcove et al. 1998, p. 608). Nonnative invasive plants alter ecosystem attributes including geomorphology, fire regime, hydrology, microclimate, nutrient cycling, and productivity (Dukes and Mooney 2004, pp. 411-437). Nonnative invasive plants can detrimentally affect native plants through competitive exclusion, altered pollinator behaviors, niche displacement, hybridization, and changes in insect predation (D'Antonio and Vitousek 1992, pp. 74-75; DiTomaso 2000, p. 257; Mooney and Cleland 2001, p. 5449; Levine et al. 2003, p. 776; Traveset and Richardson 2006, pp. 211-213).

As of 2010, YNP has documented 218 nonnative plant species occurring within its boundaries (NPS 2010e, p. 1). Encroachment of invasive plants may potentially affect A. ammophila, as this species prefers open, sparsely vegetated sites and does not compete well in areas that are more densely vegetated.

Currently, nonnative invasive plants have affected only a few sites occupied by Abronia ammophila (NPS 1999b, p. 8; Whipple 2010a, pers. comm.). The invasive grass Bromus tectorum (cheatgrass) has been noted in the vicinity of the North Shore population, and Cirsium arvense (Canada thistle) occurs near the Rock Point population (Whipple 2010a, pers. comm.). Additionally, some B. tectorum was documented around the Storm Point population (NPS 1999b, p. 8). To combat these occurrences, YNP has an exotic vegetation management plan in place that emphasizes prevention, education, early detection and eradication, control, and monitoring (Olliff et al. 2001, entire).

In summary, nonnative invasive plants occur within YNP; however, the majority of these species do not impact the habitat of Abronia ammophila. A few nonnative invasive species have been documented near the habitat of A. ammophila. These species are being monitored and the National Park System (NPS) has mechanisms in place to help control these encroachments. We have no information indicating that nonnative invasive species are modifying the species habitat to the extent that it represents a threat to the species now or in the foreseeable future.

Climate Change

The Intergovernmental Panel on Climate Change (IPCC) was established in 1988 by the World Meteorological Organization and the United Nations Environment Program in response to growing concerns about climate change and, in particular, the effects of global warming. The IPCC Fourth Assessment Report (IPCC 2007, entire) synthesized the projections of the Coupled Model Intercomparison Project (CMIP) Phase 3, a coordinated large set of climate model runs performed at modeling centers worldwide using 22 global climate models (Ray et al. 2010, p. 11). Based on these projections, the IPCC has concluded that the warming of the climate system is unequivocal, as evidenced from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level (IPCC 2007, pp. 6, 30; Karl et al. 2009, p. 17). Changes in the global climate system during the 21st century are likely to be larger than those observed during the 20th century (IPCC 2007, p. 19). Several scenarios are virtually certain or very likely to occur in the 21st century including: (1) Over most land, weather will be warmer, with fewer cold days and nights, and more frequent hot days and nights; (2) areas affected by drought will increase; and (3) the frequency of warm spells and heat waves over most land areas will likely increase (IPCC 2007, pp. 13, 53).

In some cases, climate change effects can be demonstrated and evaluated (e.g., McLaughlin et al. 2002, p. 6073). Where regional effects from global climate change have been demonstrated, we can rely on that empirical evidence to predict future impacts, such as increased stream temperatures (see status review for Rio Grande cutthroat trout, 73 FR 27900; May 14, 2008) or loss of sea ice (see determination of threatened status for the polar bear, 73 FR 28212; May 15, 2008), and treat these effects as a threat that can be analyzed. In instances for which a direct cause and effect relationship between global climate change and regional effects to a specific species has not been documented, we rely primarily on synthesis documents (e.g., IPCC 2007, entire; Independent Scientific Advisory Board 2007, entire; Karl et al. 2009, entire) to inform our evaluation of the extent that regional impacts due to climate change may affect our species. These synthesis documents present the consensus view of climate change experts from around the world. Additionally, we have examined models downscaled to specific regions (e.g., Ray et al. 2010, entire; WRCC 2011, p. 1; CIG 2011, p. 1)—including some in-progress finer-scaled models that include Wyoming and the surrounding area—in order to inform our evaluation of the extent that regional impacts may threaten species. Typically, the projections of downscaled models agree with the projections of the global climate models (Ray et al. 2010, p. 25). Climate change projections are based on models with assumptions and are not absolute.

Portions of the global climate change models can be used to predict changes at the regional-landscape scale; however, this approach contains higher levels of uncertainty than using global models to examine changes on a larger scale. The uncertainty arises due to various factors related to difficulty in applying data to a smaller scale, and to the paucity of information in these models such as regional weather patterns, local physiographic conditions, life stages of individual species, generation time of species, and species reactions to changing carbon dioxide levels. Additionally, global climate models do not incorporate a variety of plant-related factors that could be informative in determining how climate change could affect plant species (e.g., effect of elevated carbon dioxide on plant water-use efficiency, the physiological effect to the species of exceeding the assumed (modeled) bioclimatic limit, the life stage at which the limit affects the species (seedling versus adult), the life span of the species, and the movement of other organisms into the species' range) (Shafer et al. 2001, p. 207). Moreover, empirical studies are needed on what determines the distributions of species and species assemblages.

Regional landscapes also can be examined by downscaling global climate models. Two common methods of downscaling are statistical downscaling and dynamic downscaling (Fowler et al. 2007, p. 1548). These downscaled models typically inherit the broad-scale results of global climate change models, imbed additional information, and run the models at a finer scale (Ray et al. 2010, p. 25, Hostetler 2011, pers. comm.). These methods provide additional information at a finer spatial scale (i.e., all of Wyoming downscaled to a 15-km (9.3-mi) resolution (Hostetler 2010, pers. comm.). However, they are not able to account for the myriad of processes that may affect a species that only inhabits a narrow range, as local effects may reduce or amplify the large-scale patterns that are projected over the larger spatial resolution of the global climate models (Ray et al. 2010, p. 24). In summary, global climate models can play an important role in characterizing the types of changes that may occur, so that the potential impacts on natural systems can be assessed (Shafer et al. 2001, p. 213). However, they are of limited use to assess local impacts to species with a limited range, such as the five plants discussed in this finding.

Climate change is likely to affect the habitat of Abronia ammophila, but we lack scientific information on what those changes may ultimately mean for the status of the species . Yellowstone Lake water levels affect habitat conditions for A. ammophila. As noted previously, the record high lake levels of 1996 and 1997 (due to increased snowpack and subsequent spring snowmelt) had both positive and negative effects on A. ammophila (NPS 1999b, p. 7; Whipple 2002, p. 265). In general, the outflow and maximum water surface elevation of Yellowstone Lake are functions of winter snow accumulation and spring precipitation inputs; these vary significantly from year to year (Farnes 2002, p. 73). Analysis of snow depth and last date of snow cover in YNP from 1948 to 2003 has shown that winters are getting shorter, as measured by the number of days with snow on the ground (Wilmers and Getz 2005, entire). This change is due to decreased snowfall and an increase in the number of days with temperatures above freezing (Wilmers and Getz 2005, entire).

Climate change effects are not limited to the timing and amount of precipitation; other factors potentially influenced by climate change may in turn affect the habitat conditions for Abronia ammophila. For example, fire frequency, insect populations (e.g., mountain pine beetle, Dendroctonus ponderosae), and forest pathogens may be influenced by climate change (Logan and Powell 2001, p. 170; Westerling et al. 2006, pp. 942-943) and may in turn affect forest canopy cover and the timing of snowmelt within the Yellowstone Lake watershed. The increased rate of snowmelt caused by fire-generated openings in the forest canopy from the 1988 fires in YNP may have slightly reduced the annual maximum Yellowstone Lake level because it spread the snowpack melt rate over a longer period of time (Farnes 2002, p. 73). Impacts of specific events on A. ammophila and its habitat have not been analyzed.

Climate change is likely to affect multiple variables that may influence the availability of habitat for A. ammophila. As lake levels have fluctuated in the past and A. ammophila has adapted to these fluctuations, this species should be able to persist so long as climate change does not result in extreme changes to important characteristics of the species habitat, such as the complete loss of water from Yellowstone Lake. At this time, the best available scientific information does not indicate that impacts from climate change are likely to threaten the species now or in the foreseeable future.

Drought

Precipitation studies show that YNP weather cycles typically follow the larger weather patterns across the larger Northern Rockies ecosystem (Gray et al. 2007, p. 24). The reconstruction of precipitation levels in YNP from AD 1173-1998 shows strong interannual variability (Gray et al. 2007, entire). Moreover, extreme wet and dry years, which have occurred recently, fall within the range of past variability (Gray et al. 2007, entire).

We believe that Abronia ammophila has evolved to adapt to recurring drought conditions because it persists in this type of environment. Short-term population fluctuations appear to be typical for the species. The population at Rock Point was thought to have been extirpated due to drought; however, a survey in 2004 located seedlings at this site (Saunders and Sipes 2004, p. 4). The Pumice Point population completely vanishes some years. It is located on sand that does not connect to the aquifer, and during drought years the population can be 9.1 m (30 ft) above water (Whipple 2010e, pers. comm.). Although drought may temporarily influence the abundance of plants at some specific locations, we have no information indicating that drought threatens the species now or in the foreseeable future.

Summary of Factor A

YNP offers protection of Abronia ammophila populations from all kinds of development including roads, campgrounds, buildings, mining, and energy development. There are currently no plans for any further development in YNP near the existing populations or potential habitat of A. ammophila. We have no information to suggest that trampling, nonnative invasive plants, climate change, or drought represents a threat to the species.

We conclude that the best scientific and commercial information available indicates that Abronia ammophila is not in danger of extinction or likely to become so within the foreseeable future because of the present or threatened destruction, modification, or curtailment of its habitat or range.

Factor B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

There has been limited use and collection of Abronia ammophila and its parts for scientific study (Saunders and Sipes 2006, p. 77). Additionally, the Denver Botanical Gardens (DBG) collected approximately 3,300 A. ammophila seeds in 2005 (DBG 2008, p. 3). The DBG is a participating institution in the Center for Plant Conservation, an organization dedicated to preventing the extinction of plants native to the United States (Center for Plant Conservation 2010, unpaginated). Because these collections were limited, we do not believe this collection constituted a threat to the species. The collections also contribute to the long-term conservation of the species.

Specimens, seeds, and parts of Abronia ammophila are occasionally collected for scientific purposes in order to increase the knowledge of this species (e.g., Saunders and Sipes 2006; DBG 2008); however, these collections are rare. We do not have any evidence of risks to A. ammophila from overutilization for commercial, recreational, scientific, or educational purposes, and we have no reason to believe this factor will become a threat to the species in the future. We conclude that the best scientific and commercial information available indicates that A. ammophila is not in danger of extinction or likely to become so within the foreseeable future because of overutilization for commercial, recreational, scientific, or educational purposes.

Factor C. Disease or Predation

Disease

Abronia ammophila is not known to be affected or threatened by any disease. Therefore, we do not consider disease to be a threat to A. ammophila now or in the foreseeable future.

Predation—Grazing and Herbivory

No studies have been conducted investigating the effects of grazing or herbivory on Abronia ammophila. Minimal insect herbivory has been noted. Sphingid moth larvae and others tentatively identified in the family Noctuidae have been seen feeding on the aboveground plant parts (Saunders and Sipes 2004, p. 11). Also, what appeared to be an army cutworm caterpillar was observed eating the belowground parts of an uprooted plant (NPS 1999b, p. 7).

Additionally, some uprooted, partially eaten taproots were found in areas with abundant rodent tunnels (NPS 1999b, p. 7). Ungulate grazing has been noted on species that grow near Abronia ammophila; however, none has been noted on A. ammophila (NPS 1999b, p. 7). Any predation, as noted above, would represent a natural ecological interaction in YNP. We have no evidence that the extent of such predation represents a population level threat to A. ammophila. Therefore, we do not consider predation to be a threat to the species now or in the foreseeable future.

Summary of Factor C

We have no evidence of adverse impacts to Abronia ammophila from disease or predation. We conclude that the best scientific and commercial information available indicates that A. ammophila is not in danger of extinction or likely to become so within the foreseeable future because of disease or predation from herbivory or grazing.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

The Act requires us to examine the adequacy of existing regulatory mechanisms with respect to threats that may place Abronia ammophila in danger of extinction or likely to become so in the future. Existing regulatory mechanisms that could have an effect on potential threats to A. ammophila include (1) local land use laws, processes, and ordinances; (2) State laws and regulations; and (3) Federal laws and regulations. A. ammophila occurs entirely on Federal land under the jurisdiction of the YNP; therefore, the discussion below focuses on Federal laws. Actions adopted by local groups, States, or Federal entities that are discretionary, including conservation strategies and guidance, are not regulatory mechanisms; however, we may discuss them in relation to their effects on potential threats to the species.

Federal Laws and Regulations

Yellowstone National Park

All known populations of Abronia ammophila occur within YNP. The YNP was established as the first national park on March 1, 1872, under control of the Secretary of the Department of the Interior (NPS 2010c, unpaginated). The NPS was established by the NPS Organic Act of 1916, and reaffirmed by the General Authorities Act, as amended (NPS 2008a, unpaginated; Schneider 2010, pers. comm.). The NPS Organic Act states, “[The NPS] shall promote and regulate the use of the Federal areas known as national parks, monuments, and reservations* * * to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations” (16 USC 1) (NPS 2006b, p. 8; NPS 2008a, unpaginated; Schneider 2010, pers. comm.).

Additionally, the Management Policies of the NPS state that conservation is paramount in situations of conflict between conserving resources and values and providing for enjoyment of them (NPS 2006b, p. 9; Schneider 2010, pers. comm.). These policies also charge the NPS with preserving the fundamental physical and biological processes, and maintaining all the components and processes of a naturally evolving park ecosystem, including the natural abundance, diversity, and genetic and ecological integrity of the plant and animal species native to those ecosystems (NPS 2006b, pp. 35-36; Schneider 2010, pers. comm.). The NPS is responsible for the inventory of native species that are of special management concern to parks (such as rare, declining, sensitive, or unique species and their habitats) and will manage them to maintain their natural distribution and abundance (NPS 2006b, pp. 45-46; Schneider 2010, pers. comm.). The Management Policies also direct the NPS to control detrimental nonnative species and manage detrimental visitor access (NPS 2006, p. 45).

As stated above, YNP is required, to the maximum extent practicable, to prevent exotic (nonnative invasive) plant introduction and to control established exotic plants by law, executive order, and management policy (e.g., Executive Order 13112, National Park Service Management Policies (NPS 1988), and the Federal Noxious Weed Act of 1974) (Olliff et al. 2001, pp. 348-349). YNP's approach emphasizes prevention, education, early detection and eradication, control, and monitoring (Olliff et al. 2001, entire).

Visitors to national parks are prohibited from removing, defacing, or destroying any plant, animal, or mineral; this includes collecting natural or archeological objects (NPS 2006c, p. 2). Visitors are prohibited from driving off roadways or camping outside of designated campgrounds (NPS 2010d, unpaginated). Additionally, YNP has developed a Conservation Plan for Abronia ammophila (NPS 1999b, entire). This plan recommends the protection of all known (and any newly discovered) populations, monitoring of the populations, reestablishment of historical occupancy areas, long-term seed storage, and research (NPS 1999b, pp. 10-11).

National Environmental Policy Act

All Federal agencies are required to adhere to the National Environmental Policy Act (NEPA) of 1970 (42 U.S.C. 4321 et seq.) for projects they fund, authorize, or carry out. The Council on Environmental Quality's regulations for implementing NEPA (40 CFR 1500-1518) state that agencies shall include a discussion on the environmental impacts of the various project alternatives, any adverse environmental effects which cannot be avoided, and any irreversible or irretrievable commitments of resources involved (40 CFR 1502). Additionally, activities on non-Federal lands are subject to NEPA if there is a Federal nexus. The NEPA is a disclosure law, and does not require subsequent minimization or mitigation measures by the Federal agency involved. Although Federal agencies may include conservation measures for sensitive species as a result of the NEPA process, any such measures are typically voluntary in nature and are not required by the statute.

Summary of Factor D

We considered the adequacy of existing regulatory mechanisms to protect Abronia ammophila. We believe the existing regulatory mechanisms, especially the NPS Organic Act, adequately protect the Yellowstone Lake shore habitat of Abronia ammophila from the potential threats of development, trampling, and nonnative invasive plants. We expect that A. ammophila and its habitat will be generally protected from direct human disturbance. Therefore, we conclude that the existing regulatory mechanisms are adequate to protect A. ammophila from the known potential threat factors.

We conclude that the best scientific and commercial information available indicates that Abronia ammophila is not in danger of extinction or likely to become so within the foreseeable future because of inadequate regulatory mechanisms.

Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence

Natural and manmade factors with the potential to affect Abronia ammophila include: (1) Small population size, (2) pollination, and (3) genetic diversity.

Small Population Size

Small populations can be especially vulnerable to environmental disturbances such as habitat loss, nonnative species, grazing, and climate change (Barrett and Kohn 1991, p. 7; Oostermeijer 2003, p. 21; O'Grady 2004, pp. 513-514). However, plants that are historically rare may have certain adaptations to rarity (e.g., early blooming, extended flowering, or mixed-mating systems) that enable them to persist (Brigham 2003, p. 61).

Based on herbarium records, extirpation of Abronia ammophila sites has occurred (see Distribution and Abundance discussion above). However, additional sites also have been recently discovered, and not all suitable habitat within YNP has been surveyed (NPS 1999a, pp. 6-7). We have no information on whether these new sites represent recent expansion of the species or if surveys were not previously conducted in these areas.

We do not have any indication that Abronia ammophila was ever present on the landscape over a more extensive range. Existing sites are monitored, and surveys have located new occurrences. We have no information indicating that random demographic or environmental events are a threat to the species now or in the foreseeable future because of its small population size.

Pollination

Small populations may represent an unreliable food source, which may be visited by fewer pollinators than larger, less fragmented populations (Oostermeijer 2003, p. 23). However, low visitation rates may be more of a concern in currently rare species that were historically abundant (Brigham 2003, p. 84). We have no information suggesting that Abronia ammophila was previously more abundant across the landscape. Co-flowering species (species that flower during the same timeframe) also may be important to pollination of A. ammophila; the pollinators recorded as visiting A. ammophila also were observed visiting other dune plants in the vicinity (Saunders and Sipes 2004, p. 13).

Only very limited information is available regarding pollination of Abronia ammophila. However, A. ammophila is a historically rare species that exhibits a mixed-mating system. A mixed-mating system and co-flowering species may help alleviate negative effects that may occur due to low pollination visitation rates. Therefore, we have no information indicating that poor pollination is a threat to the species now or in the foreseeable future.

Genetic Diversity

Small population size can decrease genetic diversity due to genetic drift (the random change in genetic variation each generation), and inbreeding (mating of related individuals) (Antonovics 1976, p. 238; Ellstram and Elam 1993, pp. 218-219). Genetic drift can decrease genetic variation within a population by favoring certain characteristics and, thereby, increasing differences between populations (Ellstram and Elam 1993, pp. 218-219). Self-fertilization and low dispersal rates can cause low genetic diversity due to inbreeding (Antonovics 1976, p. 238; Barrett and Kohn 1991, p. 21). This decreased genetic diversity diminishes a species' ability to adapt to the selective pressures of a changing environment (Newman and Pilson 1997, p. 360; Ellstrand 1992, p. 77).

Limited information is available regarding the genetic diversity of the Abronia genus. No information is available regarding the genetic diversity exhibited by Abronia ammophila. Therefore, we have no information indicating that a lack of genetic diversity is a threat to the species now or in the foreseeable future.

Summary of Factor E

Abronia ammophila is a historically rare species that, as such, has adaptations such as a mixed-mating system and prolific flowering, which minimize the risks of small population size, low pollinator abundance, and genetic diversity. Therefore, we conclude that the best scientific and commercial information available indicates that Abronia ammophila is not in danger of extinction or likely to become so within the foreseeable future because of small population size, pollination, or reduced genetic diversity.

Finding for Abronia ammophila

As required by the Act, we considered the five factors in assessing whether Abronia ammophila is threatened or endangered throughout all of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by A. ammophila. We reviewed the petition, information available in our files, other available published and unpublished information, and we consulted with recognized A. ammophila experts and other Federal and State agencies.

The primary factor potentially impacting Abronia ammophila is human disturbance through trampling. However, studies that have sought to quantify foot traffic in the habitat of A. ammophila have found that there is little foot traffic occurring (NPS 1999a, pp. 2, 5). Additionally, A. ammophila prefers open sites and thrives under some disturbance. Other factors potentially affecting A. ammophila—including nonnative invasive plants, drought, small population size, limited pollinators, and genetic diversity—are either limited in scope, or lacking evidence apparent to us indicating that they adversely impact the species. We have no evidence that overutilization, disease, or predation are affecting this species. Although climate change will likely impact the status of some plant species in the future, we do not have enough information to determine that climate change will result in a species-level response from A. ammophila. Additionally, the existing regulatory mechanisms directing management of YNP appear to be adequate to protect the species from potential threats.

Based on our review of the best available scientific and commercial information pertaining to the five factors, we find that the threats are not of sufficient imminence, intensity, or magnitude to indicate that Abronia ammophila is in danger of extinction (endangered) or likely to become endangered within the foreseeable future (threatened), throughout all of its range. Therefore, we find that listing A. ammophila as a threatened or endangered species is not warranted throughout its range.

Significant Portion of the Range

Having determined that Abronia ammophila does not meet the definition of a threatened or endangered species, we must next consider whether there are any significant portions of the range where A. ammophila is in danger of extinction or is likely to become endangered in the foreseeable future.

In determining whether Abronia ammophila is threatened or endangered in a significant portion of its range, we first addressed whether any portions of the range of A. ammophila warrant further consideration. We evaluated the current range of A. ammophila to determine if there is any apparent geographic concentration of the primary stressors potentially affecting the species including trampling, nonnative invasive plants, drought, small population size, limited pollinators, and genetic diversity. This species' small range suggests that stressors are likely to affect it in a uniform manner throughout its range. However, we found the stressors are not of sufficient imminence, intensity, magnitude, or geographically concentrated such that it warrants evaluating whether a portion of the range is significant under the Act. We do not find that A. ammophila is in danger of extinction now, nor is likely to become endangered within the foreseeable future, throughout all or a significant portion of its range. Therefore, listing A. ammophila as threatened or endangered under the Act is not warranted at this time.

We request that you submit any new information concerning the status of, or threats to, Abronia ammophila to our Wyoming Ecological Services Field Office (see ADDRESSES section) whenever it becomes available. New information will help us monitor A. ammophila and encourage its conservation. If an emergency situation develops for A. ammophila, or any other species, we will act to provide immediate protection.

Species Information for Agrostis rossiae

Species Description

Agrostis rossiae is a small annual grass in the family Poaceae (Clark et al. 1989, p. 8; Fertig 1994, unpaginated; 2000c, unpaginated). A. rossiae grows as a dense clump about 5 to 15 cm (2.0 to 5.9 in.) high (Fertig 2000c, unpaginated). The short leaves are 1.0 to 2.5 cm (0.39 to 0.98 in.) long, and 0.5 to 2.0 millimeters (mm) (0.02 to 0.08 in.) wide, with slightly inflated and smooth sheaths (the lower part of the leaf that surrounds the stem) (Clark et al. 1989, p. 8; Clark and Dorn 1981, p. 10; Fertig 1994, unpaginated; 2000c, unpaginated). The one-flowered spikelets (flowers) form at the top of the stems in a narrow, compact panicle (a structure in which the flowers mature from the bottom upwards) that is 2.0 to 6.0 cm (0.79 to 2.36 in.) long (Dorn 1980, p. 59; Fertig 2000c, unpaginated). The panicle remains compact at maturity (Fertig 1994, unpaginated). Branches of the panicle are scabrous (rough), purple, and lack spikelets at the base (Clark et al. 1989, p. 8; Dorn 1980, p. 59; Fertig 2000c, unpaginated).

Discovery and Taxonomy

Edith A. Ross collected the first recorded specimen of Agrostis rossiae in July of 1890 (Vasey 1982, p. 77; Hitchcock 1905, p. 41). The genus Agrostis consists of over 100 species occurring in both hemispheres, typically in cooler areas of temperate climates (Hitchcock 1905, p. 5). More recent sources list 150 to 200 species (Harvey 2007, unpaginated), or up to 220 species within the Agrostis genus (Watson and Dallwitz 1992, unpaginated).

Species of the Agrostis genus are able to form morphologically similar ecotypes (subspecies that survives as a distinct group due to environmental pressures and isolation) in response to variations in climate, heavy metals in the soil, and other unusual soil conditions (Bradshaw 1959, entire; Jowett 1964, p. 78; Aston and Bradshaw 1966, entire; Jain and Bradshaw 1966, pp. 415-417). Therefore, morphology of Agrostis species is not a reliable indicator of species (Tercek 2003, p. 9).

In the geothermally influenced areas of YNP, thermal Agrostis scabra (rough bentgrass) is sympatric (occurs in the same area) with Agrostis rossiae (Tercek 2003, pp. 9-10). A. scabra occurs as an annual in the thermal areas of YNP; however, this species is typically a perennial when it occurs in nonthermal habitats (Fertig 2000c, unpaginated; Tercek 2003, pp. 9-10). A. scabra can be distinguished from A. rossiae, when mature, by its spreading panicle (Fertig 1994, unpaginated; 2000c, unpaginated; Tercek 2003, pp. 9-10). Another similar species, although not sympatric, is Agrostis variabilis (mountain bentgrass), which is a perennial with panicle branches bearing spikelets nearly to the base (whereas A. rossiae lacks spikelets at the base) (Fertig 1994, unpaginated; Fertig 2000c, unpaginated). Genetic studies have shown that thermal Agrostis species occurring in YNP are more closely related to other thermal Agrostis species worldwide than to the nonthermal Agrostis scabra (Tercek 2003, pp. 17-21). Additionally, A. rossiae and thermal A. scabra are closely related to each other (Tercek et al. 2003, p. 1308-1309); however, additional genetic studies need to be completed to quantify their relationship. We recognize A. rossiae as a valid species and a listable entity.

Biology and Life History

Agrostis rossiae is a thermal species that takes advantage of the warmth from its environment and germinates from December to January, when nonthermal areas remain covered in snow (Tercek 2003, pp. 12, 45, 51). The growing season for A. rossiae is from December 1 to April 1; it blooms in May, matures in June, and dies by mid-June when the thermal ground temperature reaches between 40 and 45 °C (104 and 113 °F) (a temperature that kills A. rossiae) (Beetle 1977, p. 40; Tercek 2003, pp. 10, 34, 12, 45, 51-52).

Agrostis rossiae plants do not have a reduced seed set when isolated from external pollen sources; this suggests that A. rossiae reproduces through apomixis (reproduction that does not involve pollination) (Tercek 2003, p. 19). Seeds remain viable for about 100 years in artificial conditions, but persist for less time in natural conditions (Tercek 2010, pers. comm.). Seeds do not disperse very far from the parent plant (Whipple 2010a, pers. comm.).

Habitat

Typically, Agrostis rossiae grows on glacial deposits, which are at a slightly higher elevation than nearby hot springs (Tercek 2003, p. 11). These deposits border active geysers and hot springs at elevations of 2,210 to 2,256 m (7,250 to 7,400 ft) (Clark et al. 1989, p. 8; Fertig 1994, unpaginated; 2000c, unpaginated). These geothermally influenced soils remain moist throughout the year even though they are partially isolated from the water table of nearby hot springs by the higher elevation or a nonpermeable rock layer (White et al. 1971, p. 77; Fournier 1989, pp. 20-21; Tercek 2003, pp. 36, 45-46; Tercek and Whitbeck 2004, p. 1956).

The geysers in YNP are vapor-dominated, meaning that steam and other gases rise out of the ground (Fournier 1989, pp. 20-21; Tercek 2003, p. 36). The geysers are important to the soils because the elements and chemicals produced from the geysers affect the composition of the soil on which this species grows. The accompanying soils are rich in silica and calcium, and contain gases such as hydrogen sulfide and iron sulfide that are converted into sulfuric acid by bacteria (Tercek and Whitbeck 2004, p. 1956; White et al. 1971, p. 77; Fournier 1989, pp. 20-21; Tercek 2003, p. 36). The sulfuric acid lowers the pH (a measure of acidity and alkalinity) of the soil (White et al. 1971, p. 77; Fournier 1989, pp. 20-21; Tercek 2003, p. 36). YNP's thermal soils are more acidic (pH 3.9-5.6), in general, than the nonthermal soils (pH 4.3-6.4) (Tercek and Whitbeck 2004, p. 1964). Agrostis rossiae demonstrates peak growth in acidic soils (pH 3.0), whereas the optimal growth of both thermal and nonthermal Agrostis scabra occurs at a pH of 5.0 (Terceck and Whitbeck 2004, p. 1964). While A. rossiae is more tolerant of acidity than other sympatric Agrostis species, its growth declines at pH of less than 3.0 (Tercek and Whitbeck 2004, p. 1964). Many of the thermal features in YNP have a very high acidity (Whipple 2011, pers. comm.).

In addition to Agrostis scabra, a limited number of thermally adapted species occur in the same habitat as Agrostis rossiae: Racomitrium canescens (Racomitrium moss), several heat-loving soil fungi, a heat-tolerant grass—Dichanthelium lanuginosum (panicgrass), and a few annual forbs (Tercek and Whitbeck 2004, p. 1956). Annual forbs include Conyza canadensis (Canadian horseweed), Gnaphalium stramineum (cottonbatting plant), Plantago elongata (Prairie plantain), Mimulus guttatus (seep monkeyflower), and Heterotheca depressa (hairy false goldenaster) (Fertig 2000c, unpaginated).

Distribution and Abundance

Agrostis rossiae is endemic to YNP, occurring only in Teton County, Wyoming (Beetle 1977, p. 40; Clark and Dorn 1981, p. 10; Clark et al. 1989, p. 8; Fertig 2000c, unpaginated, Tercek 2003, p. 10). Even though there are many thermal areas in YNP, Agrostis rossiae only occurs in the west-central portion of YNP (Tercek 2003, p. 10). Specifically, A. rossiae only occurs in the Firehole River drainage and the Shoshone Geyser Basin (Greater Yellowstone 2010, unpaginated). The reason for this restriction is not known. One proposed hypothesis is that the high acidity of some of the other thermal areas restricts the species' distribution; another is that A. rossiae is a fairly recently evolved species that has not had time for successive generations to disperse and colonize a wider area (Whipple 2010e, pers. comm.).

Four known populations of the plant occur in an area of approximately 4.86 ha (12 ac); these populations are named Upper Geyser Basin, Shoshone, Midway, and Lower Geyser (Whipple 2010a, pers. comm.). Many of these occurrences are ephemeral (only persist for a short period) subpopulations (Fertig 2000c, unpaginated). Because of the changing thermal habitat, subpopulation numbers and locations may fluctuate greatly (Fertig 2000c, unpaginated). One small (generally less than 50 plants) subpopulation northeast of Infant Geyser in Geyser Hill disappeared due to changes in soil temperatures between 1992 and 2008 (Fertig 2000c, unpaginated; Whipple 2010e, pers. comm.).

The WNDD has designated Agrostis rossiae as a plant species of concern with ranks of G1 and S1 (Heidel 2007, p. 1). This designation indicates that A. rossiae is considered to be critically imperiled because of extreme rarity. For background information on G1 and S1 rankings, please refer to the last paragraph under Distribution and Abundance in the Species Information for Abronia ammophila section. Since A. rossiae is endemic to Wyoming, the Wyoming occurrences encompass the entire global range. Additionally, YNP considers A. rossiae to be a sensitive species of concern; therefore, it evaluates effects to this species in conjunction with any project or action that has the potential to affect the plant (Whipple 2011, pers. comm.).

Trends

Subpopulations can range in size from a solitary plant up to several thousand plants, in an area with a diameter of 100 m (328.1 ft) (Tercek 2003, p. 10; Tercek and Whitbeck 2004, p. 1956). Surveys conducted in 1995 suggest that the total population of all known Agrostis rossiae plants is approximately 5,000 to 7,500 individuals (Fertig 2000a, p. 36; 2000a, unpaginated). The 1998 survey determined the total population consisted of between 5,580 and 7,735 plants (Whipple in litt. 2009, entire). The entire population has not been surveyed in any additional years (Whipple in litt. 2009, entire). Surveys have been completed on a sporadic schedule, with not all populations surveyed in a given year (Whipple 2009 in litt., unpaginated). All population counts are estimates as A. rossiae is an annual with a clumped growth form, and exact counts are unable to be obtained without destroying the plants (Whipple 2010d, pers. comm.). Overall, there is not enough information to conclusively determine rangewide trends; however, the total population numbers appear to be stable despite subpopulation fluctuations. Additionally, the known populations have expanded in the last 3 years (Whipple 2010a, pers. comm.).

Five Factor Evaluation for Agrostis rossiae

Information pertaining to Agrostis rossiae in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

The following potential factors that may affect the habitat or range of Agrostis rossiae are discussed in this section, including: (1) Development, (2) trampling, (3) nonnative invasive species, (4) climate change, (5) thermal fluctuations, (6) drought, and (7) fire.

Development

Agrostis rossiae occurs entirely inside YNP, which limits potential threats to its habitat from development. As stated above (see Factor D under Abronia ammophila), YNP owns both its land and the mineral rights so energy development within the YNP's boundary is not a threat (Mazzu 2010, pers. comm.; Whipple 2010e, pers. comm.).

In the late 1970s and early 1980s, potential for geothermal energy development outside YNP was considered a threat to Agrostis rossiae because of the potential to affect the thermal basin that underlies YNP (Fertig 2000, unpaginated). Currently, no known applications for geothermal leases have this potential (Mazzu 2010, pers. comm.; Whipple 2010e, pers. comm.). However, applications are occasionally made for geothermal leases in the geothermal areas outside of YNP (NPS 2008b, unpaginated). The Geothermal Steam Act of 1970 (30 U.S.C. 1001-1027, December 24, 1970), as amended in 1977, 1988, and 1993, provides protections for the thermal features in YNP (see Factor D. The Inadequacy of Existing Regulatory Mechanisms below) (Legal Information Institute 2010, unpaginated). This law should protect the species, unless high energy costs, such as occurred in the late 1970s and early 1980s, encourage development interest that results in changes that weaken these protections. Therefore, A. rossiae is not threatened by geothermal energy development inside or outside of YNP's boundary.

As stated above, new construction of roads, trails, or structures occurring in YNP is rare, with reconstruction of existing features occurring occasionally (Whipple 2010e, pers. comm.). When new construction or reconstruction occurs in areas where there are sensitive species, YNP analyzes and carries out construction in a manner that minimizes adverse effects. For example, the reconstruction of the Biscuit Basin Boardwalk in the summer of 2010 included rerouting the boardwalk and restoration of Agrostis rossiae habitat that had been impacted during prior maintenance (Whipple 2010a, pers. comm.; 2010e, pers. comm.).

The majority of YNP remains undeveloped, and we have no information that this will change; therefore, we do not view development to be a threat to the species now or in the foreseeable future.

Trampling

Most habitat of Agrostis rossiae is easily accessible to visitors, as it is generally located near popular thermal features in YNP (Whipple 2010a, pers. comm.). However, visitors are required to stay on boardwalks and designated trails around thermal areas (NPS 2006c, unpaginated). Human impact to A. rossiae was noted in a survey of the Shoshone Geyser Basin area (Whipple 2009 in litt., unpaginated). This trampling was partially mitigated by the reroute discussed above; surveys in 2000, after the trail was rerouted, documented a healthy A. rossiae population (Whipple 2009 in litt., unpaginated). No studies have specifically examined disturbance due to trampling or its effects on A. rossiae. However, A. rossiae is typically located in the vicinity of thermal features that could be detrimental for humans to walk near, and any areas that have the potential for trampling are protected by YNP's policies.

For information on impacts of increased visitation to YNP, please refer to the “Trampling” discussion under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section. As the plant is located in YNP, it is afforded protections (see Factor D: The Inadequacy of Existing Regulatory Mechanisms below).

Wildlife, also, have the potential to trample Agrostis rossiae. American bison (Bison bison) scat (fecal droppings) has been found in the vicinity of A. rossiae at several sites; however, no trampling of A. rossiae was noted in the survey notes (Whipple 2009 in litt., unpaginated). In 1998, a small patch of A. rossiae was highly impacted by the actions of a rutting bull elk (Cervus canadensis); however, that A. rossiae population was reported to be healthy when resurveyed in 2000 (Whipple 2009 in litt., unpaginated). We believe that these anecdotal observations do not add up to routine impacts on a scale that would cause the species to be threatened or endangered. Additionally, we believe that trampling by wildlife, as noted above, represents a natural ecological interaction in YNP with which the species would have evolved and poses no threat to long-term persistence.

We have no information indicating that trampling by either humans or wildlife is a threat to the species now or in the foreseeable future.

Nonnative Invasive Plants

For general background information on nonnative invasive plants, please refer to the first paragraph of “Nonnative Invasive Plants” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section .

As stated above, as of 2010, YNP has documented 218 nonnative plant species occurring within its boundaries (NPS 2010e, p. 1). The majority of these plants have not been documented in or around Agrostis rossiae habitat. Encroachment of nonnative species has the potential to affect Agrostis rossiae. However, at this time, none of the nonnative species are able to tolerate the hottest of the thermal habitats, where A. rossiae primarily grows (Whipple 2010e, pers. comm.). Several nonnative species that are considered either invasive or exotic occur near the thermal habitats of A. rossiae (Whipple 2009 in litt., entire). In order to combat nonnative invasives that can tolerate the transition areas closer to the thermal habitat of A. rossiae, YNP is targeting Rumex acetosella (common sheep sorrel) around the Shoshone Geyser Basin (Schneider 2010 pers. comm.) and Hypericum perforatum (St. John's wort) near the Lower Geyser Basin (Whipple 2010f, pers. comm.). Additionally, NPS plans to establish trial plots in some of the geyser basins to determine the best control mechanisms (Schneider 2010 pers. comm.). Nonnative species currently occur only within the transition zones and not in the hot thermal habitat of A. rossiae. Additionally, the NPS has an exotic plant management plan (see Factor D: The Inadequacy of Existing Regulatory Mechanisms in the Five Factor Evaluation for Abronia ammophila section), which includes measures to identify and treat any new nonnatives; therefore, we believe that A. rossiae will be protected from nonnative plant invasions.

We have no information indicating that nonnative invasive species are modifying the habitat of Agrostis rossiae to the extent that they represent a threat to the species now or in the foreseeable future.

Climate Change

For general background information on climate change, please refer to the first paragraphs of “Climate Change” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

Agrostis rossiae is adapted to an ephemeral habitat subject to lethal summer soil temperatures and appears most clearly influenced by the condition of thermal features as opposed to other climatic factors. Although climate change has the potential to affect the species' habitat, it is not clear that climate change has relevance to the condition or availability of habitat for this species because we have no information that climate change will play a significant role in altering geothermal features. Climate change may affect the timing and amount of precipitation as well as other factors linked to habitat conditions for this species. We are uncertain how these changes will affect the geothermal habitat of A. rossiae. At this time the available scientific information does not clearly indicate that climate change is likely to threaten the species now or in the foreseeable future.

Thermal Fluctuations

The thermal features in YNP are part of the largest and most varied geyser basin in the world; this basin is essentially undisturbed (NPS 2008b, unpaginated). Few of YNP's thermal features have ever been diverted for human use (such as bathing pools or energy), despite the proximity of roads and trails (NPS 2008b, unpaginated). Thermal features can be affected by nearby ground-disturbing activities; water, sewer, and other utility systems adjacent to YNP have likely affected the park's features in the past (NPS 2008b, unpaginated). In other countries, geothermal drill holes and wells located 4.02 to 9.98 km (2.5 to 6.2 mi) from thermal features have reduced geyser activity and hot spring discharges (NPS 2008b, unpaginated). Connections between YNP's underlying geothermal basins are not fully understood. Therefore, if geothermal activities were to occur outside YNP, they could have the potential to affect this species.

Agrostis rossiae tends to follow very subtle geothermal features, growing along geothermal cracks and edges of sunken pools (Whipple 2010e, pers. comm.). For example, in Cathos Springs, A. rossiae currently grows along one crack and in a ring around the spring; however, when the water level is higher or the ground level hotter, the distribution shifts, or the plant may not be present at all in a given year (Whipple 2010e, pers. comm.). As discussed above, the Geothermal Steam Act of 1970 (30 U.S.C. 1001-1027, December 24, 1970), as amended in 1977, 1988, and 1993, prevents significant adverse effects to the thermal features in YNP (see Factor D: The Inadequacy of Existing Regulatory Mechanisms below) (Legal Information Institute 2010, unpaginated). Additionally, the NPS is included in discussions of activities that may affect the groundwater or geothermal areas of YNP (Mazzu 2010, unpaginated). Therefore, we have no information indicating that human-caused changes to the thermal features are likely to threaten the species now or in the foreseeable future.

Drought

For background information, please refer to the first paragraph of the “Drought” discussion under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section. As noted above under the Habitat section for this species, the vapor-dominated geothermally influenced soils on which Agrostis rossiae typically grows remain moist throughout the year (Tercek 2003, pp. 36, 45-46). However, these soils are influenced by the amount and timing of the rain that falls in the area (Tercek and Whitbeck 2004, p. 1958). Typically around May or June, the snow in the surrounding area has melted and rains are no longer frequent enough for the soils in the areas surrounding the habitat of A. rossiae to remain moist (Tercek and Whitbeck 2004, p. 1958). This decrease in soil moisture of the surrounding habitat is accompanied by a sharp increase in the thermal soil temperatures (Tercek and Whitbeck 2004, p. 1958). The typical growing season in the hot thermal habitats is approximately 120 days (Tercek and Whitbeck 2004, p. 1963). A. rossiae requires only 30 to 70 days to complete its life cycle (Tercek and Whitbeck 2004, p. 1963). A decrease in the growing season of 40 percent could occur prior to drought having a detrimental effect on this species. Prediction models indicate that areas already affected by drought will suffer greater effects from temperature increases caused by climate change and that high precipitation effects will become more frequent (IPCC 2007, entire). Although we do not fully understand how these changes will affect the habitat of A. rossiae, we do know that this species is resilient to changes in the thermal basins of its environment. Therefore, we do not believe that drought will rise to the level of a threat to the species now or in the foreseeable future.

Fire

As Agrostis rossiae completes its annual life cycle by mid-June, it is typically dead by the time fire season occurs (Whipple 2010e, pers. comm.); YNP's fire season generally extends from late June to the first large rain events in September. The fires in 1988 burned the area where A. rossiae occurs; however, the fire did not carry on the ground through the A. rossiae populations and, therefore, did not have any effect on the population (Whipple 2010e, pers. comm.). We have no information indicating that fire is likely to threaten the species now or in the foreseeable future.

Summary of Factor A

YNP offers protection to the populations of Agrostis rossiae from all kinds of development, including roads, campgrounds, buildings, mining, and energy development. There are currently no plans for any further development in YNP near the existing populations or potential habitat of A. rossiae. We have no information to show that Agrostis rossiae is likely to be threatened by trampling, nonnative species, climate change, thermal fluctuations, drought, or fire.

We conclude that the best scientific and commercial information available indicates that Agrostis rossiae is not in danger of extinction or likely to become so within the foreseeable future because of the present or threatened destruction, modification, or curtailment of its habitat or range.

Factor B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

There has been limited use and collection of the leaves of Agrostis rossiae for scientific purposes to determine the genetic relationship between different Agrostis species (Tercek 2003, p. 12). We have no indications of A. rossiae being collected for any other purposes (Whipple 2010e, pers. comm.). Therefore, we conclude that the best scientific and commercial information available indicates that A. rossiae is not in danger of extinction or likely to become so within the foreseeable future because of overutilization for commercial, recreational, scientific, or educational purposes.

Factor C. Disease or Predation

Agrostis rossiae is not known to be affected or threatened by any disease. We have no records showing predation by grazing or herbivory on A. rossiae. Therefore, we conclude that the best scientific and commercial information available indicates that A. rossiae is not in danger of extinction or likely to become so within the foreseeable future because of disease or predation.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

All known populations of Agrostis rossiae occur within YNP, which is under the jurisdiction of the NPS. Please refer to Yellowstone National Park under the Factor D: The Inadequacy of Existing Regulatory Mechanisms section in the Five Factor Evaluation for Abronia ammophila section for additional information.

The Geothermal Steam Act of 1970 (30 U.S.C. 1001-1027, December 24, 1970), as amended in 1977, 1988, and 1993, governs the lease of geothermal resources on public lands (Legal Information Institute 2010, unpaginated). In addition to preventing the issuance of geothermal leases on lands in YNP, it prevents the issuance of any lease that is reasonably likely to result in a significant adverse effect on thermal features within YNP (Legal Information Institute 2010, unpaginated).

Summary of Factor D

The existing regulatory mechanisms, especially the NPS Organic Act and the Geothermal Steam Act, appear to adequately protect Agrostis rossiae and its habitat in YNP. We expect that A. rossiae and its habitat will be generally protected from direct human disturbance. Therefore, we conclude that the existing regulatory mechanisms are adequate to protect A. rossiae from the known potential threat factors.

We conclude that the best scientific and commercial information available indicates that Agrostis rossiae is not in danger of extinction or likely to become so within the foreseeable future because of the inadequacy of existing regulatory mechanisms, provided the existing mechanisms are not weakened or removed.

Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence

Natural and manmade factors with the potential to affect Agrostis rossiae include: (1) Competition and hybridization, (2) small population size, and (3) genetic diversity.

Competition and Hybridization

Previously, Agrostis scabra has been listed as a threat to Agrostis rossiae, possibly because of competition or hybridization (e.g., Fertig 2000a; 2000c; NatureServe 2010a, p. 1). However, A. scabra is a native species that does not compete with or restrict A. rossiae (Whipple 2010a, pers. comm.). The thermal areas in which A. rossiae grows have lethal summer soil temperatures (greater than 45 °C (113 °F)) that preclude the growth of perennial roots and reproduction of any plant that requires greater than 120 days to complete its life cycle (Tercek 2003, p. 51). Nonthermal A. scabra is able to germinate in garden experiments of thermal temperatures; however, nonthermal A. scabra seldom occurs in the interior of the thermal habitats where A. rossiae occurs (Tercek 2003, p. 53). Additionally, nonthermal A. scabra requires a growing season of approximately 160 days in order to flower; the typical growing season in the transition zone between thermal and nonthermal ground is approximately 105 days (Tercek 2003, p. 52). Therefore, even if the nonthermal A. scabra germinated in the transition zone, it would be unable to reproduce before desiccation occurred.

Conversely, thermal Agrostis scabra is able to flower at the same time as Agrostis rossiae (Tercek 2003, p. 10). However, each thermal area is typically populated by only one of these species because of differences in microhabitat requirements (e.g., soil temperature, soil pH) (Tercek 2003, p. 10). A few thermal areas do support populations of both A. rossiae and thermal A. scabra (Whipple 2010e, pers. comm.); however, A. rossiae and thermal A. scabra maintain separate morphologies in these locations and when they are grown under uniform laboratory conditions (Tercek et al. 2003, p. 1311; Whipple 2010e, pers. comm.). Additionally, attempts to cross-pollinate A. rossiae and thermal A. scabra were unsuccessful; however, experiments that are more rigorous are needed to determine conclusively whether these two Agrostis species can hybridize (Tercek 2003, p. 19) and to confirm that there is not a crossbreeding effect that could be a threat to A. rossiae.

Small Population Size

For general background information on small population size, please refer to the first paragraph of “Small Population Size” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section.

We do not have any indication that Agrostis rossiae was ever present on the landscape over a more extensive range. Nor do we have any evidence that the populations of A. rossiae are sufficiently small to experience the problems that occur in some species because of small population size. Additionally, A. rossiae has the potential to expand its habitat, although potential habitat may be limited (see Distribution and Abundance) (Whipple 2010e, pers. comm.). We have no information indicating that random demographic or environmental events are a threat to the species because of a small population size. Therefore, we do not consider small population size to be a threat to A. rossiae now or in the foreseeable future.

Genetic Diversity

For general background information on genetic diversity, please refer to the first paragraph of “Genetic Diversity” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section.

Decreased genetic diversity diminishes a species' ability to adapt to the selective pressures of a changing environment (Newman and Pilson 1997, p. 360; Ellstrand 1992, p. 77). However, Agrostis rossiae continually adapts to the changing thermal conditions of its environment and is able to shift its distribution to follow these changes (Whipple 2010e, pers. comm.). Therefore, potential decreased genetic diversity does not appear to be affecting A. rossiae.

Gene flow can also have negative effects on a species (Ellstrand 1992, p. 77). Genes favoring adaptations to a different environment or hybridization between two species can result (Ellstrand 1992, p. 77). Gene flow between Agrostis populations is low (Tercek 2003, p. 19). Therefore, there may be some risk to the species, but we do not fully understand this risk based on currently available information.

Limited information is available about the genetic diversity of Agrostis rossiae. We do not have any indication that A. rossiae is at risk of suffering from reduced genetic diversity and consider it capable of adapting to changes based on our current understanding of the species' genetics. Therefore, we do not consider reduced genetic diversity to be a threat to A. rossiae now or in the foreseeable future.

Summary of Factor E

Agrostis scabra is a native species that does not outcompete or invade the habitat of Agrostis rossiae. Typically, these two species do not occur together. Additionally, we have no information to suggest that small population size or reduced genetic diversity limit A. rossiae. We conclude that the best scientific and commercial information available indicates that Agrostis rossiae is not in danger of extinction or likely to become so within the foreseeable future because of competition or hybridization, small population size, or reduced genetic diversity.

Finding for Agrostis rossiae

As required by the Act, we considered the five factors in assessing whether Agrostis rossiae is threatened or endangered throughout all of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by A. rossiae. We reviewed the petition, information available in our files, and other available published and unpublished information, and we consulted with recognized A. rossiae experts and other Federal and State agencies.

The primary factors potentially impacting Agrostis rossiae are visitor impacts, the invasion of Agrostis scabra, and changing thermal activity. However, A. scabra is a native species that typically does not compete with A. rossiae, the existing boardwalks and trails offer sufficient pathways for visitors to navigate around the thermal areas, and sufficient regulatory mechanisms exist to prevent human-caused changes to the thermal basin by groundwater or geothermal development. Other factors affecting A. rossiae—including nonnative invasive plants, drought, small population size, and genetic diversity—are either limited in scope, or lacking evidence apparent to us indicating that they adversely impact the species as a whole. We have no evidence that overutilization, disease, or predation are affecting this species. Although climate change may impact the species in the future, we do not have enough information to determine that climate change will elicit a species-level response from A. rossiae. Based on our knowledge of the species, the regulatory mechanisms to protect the species appear appropriate.

Based on our review of the best available scientific and commercial information pertaining to the five factors, we find that the threats are not of sufficient imminence, intensity, or magnitude to indicate that Agrostis rossiae is in danger of extinction (endangered), or likely to become endangered within the foreseeable future (threatened), throughout all of its range. Therefore, we find that listing A. rossiae as a threatened or endangered species is not warranted throughout all of its range.

Significant Portion of the Range

Having determined that Agrostis rossiae does not meet the definition of a threatened or endangered species, we must next consider whether there are any significant portions of the range where A. rossiae is in danger of extinction or is likely to become endangered in the foreseeable future.

In determining whether Agrostis rossiae is threatened or endangered in a significant portion of its range, we first addressed whether any portions of the range of A. rossiae warrant further consideration. We evaluated the current range of A. rossiae to determine if there is any apparent geographic concentration of the primary stressors potentially affecting the species including visitor-related impacts (trampling), changing thermal activity, nonnative invasive plants, drought, small population size, and genetic diversity. This species' small range suggests that stressors are likely to affect it in a uniform manner throughout its range. Furthermore, we found the stressors are not of sufficient imminence, intensity, magnitude, or geographically concentrated such that it warrants evaluating whether a portion of the range is significant under the Act. We do not find that A. rossiae is in danger of extinction now, nor is it likely to become endangered within the foreseeable future throughout all or a significant portion of its range. Therefore, listing A. rossiae as threatened or endangered under the Act is not warranted at this time.

We request that you submit any new information concerning the status of, or threats to, Agrostis rossiae to our Wyoming Ecological Services Field Office (see ADDRESSES section) whenever it becomes available. New information will help us monitor A. rossiae and encourage its conservation. If an emergency situation develops for A. rossiae, or any other species, we will act to provide immediate protection.

Species Information for Astragalus proimanthus

Species Description

Astragalus proimanthus is a mat-forming, stemless, perennial herb measuring 2 to 3 dm (7.9 to 11.8 in.) in diameter (Fertig 2001, unpaginated) and up to 4 cm (1.6 in.) in height (Dorn 1979 in litt., unpaginated). The densely clustered, 1.0- to 3.5-cm-long (0.39- to 1.38-in.-long) leaves are divided into three narrow, 5- to 9-mm-long (0.2- to 0.4-in.-long) leaflets (small leaflike divisions of a larger compound leaf) (Fertig and Welp 2001, p. 7). The plants are covered with fine hairs and appear silvery, with leaflets that are equally hairy on both sides (Barneby 1964, p. 1153). The 17-mm-long (0.67-in.-long), asymmetrical, pea-like flowers have five petals: one large broad upper petal, two side petals, and two lower petals that form a canoe shape (Fertig and Welp 2001, p. 7). The broad upper petal, called the banner petal, is constricted along the midline, forming a fiddle shape (Roberts 1977, p. 63). The yellow to whitish flowers are often tinged with lavender or pink, especially near the center, and occur in pairs at the base of the leaves (Fertig and Welp 2001, p. 7). This plant has a taproot that is woody and branching (Barneby 1964, p. 1153).

Discovery and Taxonomy

The first specimens of Astragalus proimanthus were discovered and collected 9.7 km (6 mi) north of the town of McKinnon (Sweetwater County, Wyoming) on June 13, 1946, by H.C. Ripely and R.C. Barneby (Barneby 1964, p. 1154). A second population was located in 1961 (Barneby 1964, p. 1154). The population discovered in 1961 was collected from and revisited multiple times in the decades that followed; however, the population discovered in 1946 could not be relocated after multiple attempts (Fertig and Welp 2001, p. 8). In 2000, two populations were discovered, one of which may be the original site collected by Barneby in 1946 as this population was found 9.7 km (6 mi) north of the town of McKinnon (Fertig and Welp 2001, p. 9).

The flowering plant genus Astragalus is the largest genus of vascular plants (Montana Plant Life 2010, unpaginated). With the common names “milk-vetch” or “locoweed” (family Fabaceae or Leguminosae), the genus contains more than 2,000 species, which are distributed worldwide, although they are primarily found in the northern hemisphere (Barneby 1989, p. 1; Montana Plant Life 2010, unpaginated). Based on similar morphological features of the flower, calyx (collective term for the sepals, which are the green, leaflike structures that protect the delicate inner parts of the flower while it is developing), and fruits, Astragalus proimanthus is in a taxonomic grouping within Oropahca (subgenus) with Astragalus gilviflorus (Dubois milkvetch) and Astragalus hyalinus (summer milkvetch), which both occur in Wyoming (Fertig and Welp 2001, p. 6). A. proimanthus has been considered a descendant of A. hyalinus (Roberts 1977, p. 63). A. proimanthus is similar to A. hyalinus in its dwarf habit of growth and short flower with fiddle-shaped banner petal, but it is dissimilar in having smooth, hairless petals and an earlier flowering period (by a month or so) (Barneby 1964, p. 1154). Additionally, A. proimanthus grows in a small, compact form and not in a large, highly curved cushion characteristic of A. hyalinus. A. proimanthus resembles A. gilviflorus in its growth form and has a similar range of numbers of seeds in the fruits; however, unlike A. gilviflorus, it has narrow, oval-shaped fruit and short, differently shaped banner petals (Barneby 1964, p. 1154). The only other Astragalus species in Wyoming with three leaflets have smaller flowers than A. proimanthus (Fertig 1994, unpaginated). All species within the subgenus Oropahca have 12 chromosomes (Roberts 1977, p. 1), but it is unknown if they are interfertile (capable of cross-pollinating or breeding with other Astragalus species) (Fertig and Welp 2001, p. 14). No evidence of hybridization between A. proimanthus and other Astragalus species has been documented (Fertig and Welp 2001, p. 14). Based on this information, we recognize A. proimanthus as a valid species and a listable entity.

Biology and Life History

Astragalus proimanthus (precocious milkvetch) is named for its early flowering period. It has been observed in flower as early as April 28, and it may continue to bloom until mid-June (Fertig and Welp 2001, p. 14). Astragalus species are typically insect-pollinated; however, we have no information specific to A. proimanthus (Heidel 2003, p. 19). Both insects and birds have been observed visiting the flowers of A. proimanthus and may be involved in pollination (Fertig and Welp 2001, p. 14). Fruits are continuously produced from mid-May through late July (Roberts 1977, pp. 43, 97). The narrow, oval fruit pods (7 to 10 mm (0.28 to 0.39 in.) long) are attached to the stems and are covered in dense, fine hair (Fertig and Welp 2001, p. 7). The fruit pods contain 11 to 14 seeds (Barneby 1964, p. 1154) that are brown and 2.0 to 3.1 mm (0.08 to 0.12 in.) long (Roberts 1977, p. 64). Fruit production may be limited during drought years as evidenced by low fruiting rates observed in 2000 (Fertig and Welp 2001, p. 14). Due to the absence of seed structures (e.g., winged edges) to enhance dispersal, seed dispersal appears passive and limited to short distances (Fertig and Welp 2001, p. 14).

Although Astragalus proimanthus is perennial, its lifespan may be shorter than is commonly assumed for mat-forming perennials, as is evidenced by shifts in location of plant subpopulations and disappearances of previously documented plant occurrences (Fertig and Welp 2001, pp. 13-14, 17). Longevity is an important life-history trait for the persistence and survival of species occurring in harsh environments where recruitment (reproductive success) is variable and unpredictable (Garcia et al. 2008, p. 261).

Habitat

Astragalus proimanthus is a narrow endemic occurring only on the shale bluffs of the Henrys Fork River, near the town of McKinnon, which is in the southern Green River Basin of southwestern Sweetwater County, Wyoming (Fertig and Welp 2001, p. 8). Sparsely vegetated rims and gullied upper slopes of benches, bluffs, and mesa-like ridges at elevations of 1,950 to 2,195 m (6,400 to 7,200 ft) provide habitat for A. proimanthus (Fertig and Welp 2001, p. 11).

Astragalus proimanthus inhabits cushion plant and bunchgrass communities dominated by Phlox hoodii (spiny phlox or carpet phlox) , Haplopappus nuttallii (rayless aster) , Cryptantha sericea (silky cryptantha), and Elymus spicatus (bluebunch wheatgrass) in openings within Artemisia tridentata (big sagebrush) and grasslands intermixed with Juniperus osteosperma (Utah juniper) (Fertig and Welp 2001, p. 11). A. proimanthus also occurs on gentle slopes at the base of ridges within a matrix of Artemisia nova (black sagebrush) , Sarcobatus vermiculatus (greasewood), J. osteosperma, and Grayia spinosa (spiny hopsage) (Fertig and Welp 2001, p. 11). This species grows in fine-textured limestone shale clays that are dry, shallow, and covered by a dense layer of coarse cobbles, whitish flakey shale, and dark volcanic rock (Fertig and Welp 2001, pp. 11-12).

Individual Astragalus proimanthus plants are often separated by apparently suitable, nonvegetated habitat, and typically occur in densities ranging from 0.18 to 3.4 plants per square meter (m²) (0.15 to 2.8 plants per square yard (yd²)) (Fertig and Welp 2001, p. 14). The habitat in which A. proimanthus grows typically has less than 5 to 10 percent vegetative cover (Fertig and Welp 2001, pp. 11-12). The absence of plants from seemingly suitable habitat may be the result of passive seed dispersal (addressed above) or episodic (occurring at irregular intervals) establishment events, such as gully washouts (Fertig and Welp 2001, p. 14).

Average annual precipitation where Astragalus proimanthus occurs is 25 cm (9.8 in.), with peak precipitation events occurring in May and June (Martner 1986 as cited in Fertig and Welp 2001, p. 12). Mean annual temperature is 4.4 °C (40 °F), with mean lows of −14.4 °C (6 °F) in January, and mean highs of 28.9 °C (84 °F) in July (Martner 1986 as cited in Fertig and Welp 2001, p. 12). The average number of days per year at or below freezing are 225 (Martner 1986 as cited in Fertig and Welp 2001, p. 12).

Distribution and Abundance

The distribution of Astragalus proimanthus consists of 3 populations which are made up of 26 subpopulations (Fertig and Welp 2001, pp. 12-13; Heidel 2010a, pers. comm.). The largest population contains 21 subpopulations and occurs within 3.2 km (2 mi) of the Henrys Fork River along an 8-km (5-mi) stretch (WNDD in litt. 2010, unpaginated). The second largest population consists of four subpopulations and occurs 12.9 km (8 mi) further upstream on the Henrys Fork River, near the mouth of Cottonwood Creek (WNDD in litt. 2010, unpaginated). The smallest population consists of one subpopulation and occurs 2.5 km (1.5 mi) north of the largest population, along Lane Meadow Creek—a tributary to the Henrys Fork River (WNDD in litt. 2010, unpaginated). The entire distribution of A. proimanthus is limited to an area of less than 129.5 ha (320 ac) within an area of 6.4 by 22.5 km (4 by 14 mi) (Fertig and Welp 2001, p. 8).

Population estimates of A. proimanthus have varied widely, probably reflecting variability in survey methods and discovery of new subpopulations (Fertig and Welp 2001, p. 13). In 1980, prior to the discovery of all 26 subpopulations, an estimated 200 plants were documented as occurring within 2 populations (Dorn 1980, p. 49). The first survey to inventory the entire known distribution was completed in May of 1981, with the total number of A. proimanthus plants estimated at 22,000 plants occurring on 97.1 ha (240 ac) (Whiskey Basin Consultants 1981, p. 5). Conclusions from field studies conducted in 1989 are that, although the distribution of A. proimanthus was limited, subpopulations within that distribution were large, containing thousands of individual plants; the total population size was estimated at 25,000 to 40,000 individuals (Fertig and Welp 2001, p. 13). However, the 1989 field studies focused on identifying new subpopulations and initiating a monitoring program, not on conducting a quantitative census (Fertig and Welp 2001, p. 13). In June 2000, a survey of 11 subpopulations representing the 3 known populations, conducted by the WNDD, resulted in a count of 2,644 individuals; this was extrapolated to a minimum total population estimate of 10,500 to 13,000 individuals (Fertig and Welp 2001, p. 13).

The distribution of A. proimanthus may be associated with the presence of a light-colored shale formation, where it is the uppermost soil layer (Whiskey Basin Consultants 1981, p. 9). The Henrys Fork River has eroded this shale formation away in some areas, causing it to be exposed over a distance of 9 km (5.5 mi) near the river (Whiskey Basin Consultants 1981, p. 9). Approximately 95 percent of the known occurrences of A. proimanthus have been found on BLM-administered lands, with 4 percent occurring on State lands, and 1 percent on private lands (Heidel 2010b, pers. comm.).

The WNDD has designated Astragalus proimanthus as a plant species of concern with ranks of G1 and S1 (Heidel 2007, p. 3). For background information on G1 and S1 rankings, please refer to the last paragraph under Distribution and Abundance in the Species Information for Abronia ammophila section. Since A. proimanthus is endemic to Wyoming, the Wyoming occurrences encompass this species' entire global range.

Trends

Population trends for Astragalus proimanthus are difficult to determine because survey methodologies have not remained consistent, baseline data are lacking, and precipitation has varied significantly during survey years (Fertig and Welp 2001, p. 13). Shifts in the distribution suggest that A. proimanthus may be shorter-lived than is often assumed for mat-forming perennials (Fertig and Welp 2001, p. 14). The importance of yearly fluctuations in precipitation and temperature to the establishment and survival of this species is unknown (Fertig and Welp 2001, p. 14).

Population counts and distribution of Astragalus proimanthus along established transects have varied during the past two decades (Fertig and Welp 2001, p. 14). Five transects were established in 1989 to evaluate changes in abundance and density of plants (Marriott 1989, Appendix D). Surveys from two transects monitored from 1989 to 1998 showed a long-term increase in numbers and densities of plants (Fertig and Welp 2001, pp. 37-47). However, numbers along a third transect decreased by 7 percent from 1989 to 1998, and then the transect could not be relocated in 2000 possibly due to a local extirpation of plants (Fertig and Welp 2001, pp. 14, 37-47). Surveys from the fourth transect showed a steady decline in overall plant numbers, reaching a 43 percent decrease in numbers by 2000 (Fertig and Welp 2001, pp. 14, 37-47). Surveys from the fifth transect revealed short-term oscillations in the population size, with numbers increasing between 1989 and 1998 and then decreasing 8 percent by 2000 (Fertig and Welp 2001, pp. 37-47). Changes in numbers and plant densities may be attributed to the short lifespans of individual plants or the lack of new plants becoming established (Fertig and Welp 2001, p. 14). Localized increases and decreases in population numbers and density may be expected for this species, as evidenced by the variable numbers and changes in spatial distributions along survey transects (Fertig and Welp 2001, p. 40). However, overall monitoring data suggest that the main population along the bluffs of the Henrys Fork River was relatively stable from 1998 to 2000 despite localized shifts in distribution (Fertig and Welp 2001, p. 14).

Five Factor Evaluation for Astragalus proimanthus

Information pertaining to Astragalus proimanthus in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

The following potential factors that may affect the habitat or range of Astragalus proimanthus are discussed in this section, including: (1) energy development, (2) road construction, (3) off-road vehicle use, (4) range improvements, (5) disposal sites, (6) nonnative invasive plants, (7) fire, and (8) climate change and drought.

Energy Development

Energy development has been identified as a potential threat to Astragalus proimanthus (Marriot 1989, p. 8, Fertig and Welp 2001, p. 16). The distribution of A. proimanthus is limited to Sweetwater County, Wyoming (WNDD in litt. 2010, unpaginated). Sweetwater County sits atop the coal seams and oil and gas reserves of the Upper Green River Basin, which by some estimates contain 10 percent of the nation's total onshore natural gas reserves, as well as the largest known trona (a source of sodium carbonate) deposit in the world (Headwaters Economics 2009, p. 26). Uranium and coal (Headwaters Economics, p. 26) as well as oil shale resources (Congressional Research Service 2008, p. 3) occur throughout the county. There also is the potential for wind energy development in Sweetwater County (BLM 2010a, unpaginated).

Oil and gas exploration and extraction; coal, uranium, and trona mining; and oil shale and wind energy development may involve ground-disturbing actions that have the potential to remove or disturb Astragalus proimanthus and its habitat (Marriott 1989, p. 8; Fertig and Welp 2001, p. 16). Oil and gas exploration and coal mining may involve drilling, using explosives, driving heavy earth-moving equipment off road, clearing land for resource extraction or project infrastructures, and constructing roads and utility lines. Oil shale development may involve converting oil shale into crude oil through a process called destructive distillation, which may require land removal (Congressional Research Service 2008, p. 4). Wind energy development involves clearing land for constructing turbine sites and infrastructure including utility lines and roads. Additionally, all energy development may result in increased human use and vehicular traffic, which can result in trampling and increased erosion in the area.

In 2000, seismic explorations took place near the mouth of Cottonwood Creek, where a population of Astragalus proimanthus occurs (Fertig and Welp, 2001, p. 16). Associated road construction may have disturbed A. proimanthus habitat, but there is no indication that plants were removed by these activities and any population-level effects are unknown. Presently, there is no ongoing energy development near the known occurrences of A. proimanthus on BLM-administered lands (Glennon 2010a, pers. comm.).

Astragalus proimanthus is a special status species designated by the BLM State Director as sensitive (BLM 1997, p. 19). This status requires that potential habitat on Federal or split estate (i.e., mixed surface and mineral ownership) lands be searched to determine if sensitive plants are located in the project area before the project occurs (BLM 1997, p. 19). Areas with special status plant populations are closed to activities that would adversely affect them, including surface disturbances, locating new mining claims, mineral material sales, all off-road vehicle (ORV) use, and use of explosives and blasting (BLM 1997, p. 19).

In the Green River Resource Management Plan (RMP), the BLM has established a Special Status Plant Species Area of Critical Environmental Concern (ACEC) that covers four plant species including Astragalus proimanthus (BLM 1997, pp. 19, 34). This ACEC protects 100 percent of A. proimanthus that occurs on BLM land (BLM 2011, unpaginated). This ACEC is closed to energy development activities that have the potential to adversely affect A. proimanthus and its habitat. Prohibited activities include surface disturbing activities and surface occupancy (such as leasable mineral exploration and development or construction of long-term facilities or structures), mineral material sales, and use of explosives and blasting (BLM 1997, pp. 19, 34). The ACEC has provisions by which any newly located A. proimanthus individuals and habitat can be added to the ACEC by an amendment to the RMP (BLM 1997, pp. 19, 34).

Additionally, BLM-administered lands under a 48.6-ha (120-ac) fenced enclosure around one of the subpopulations of Astragalus proimanthus, north of the town of McKinnon, have been withdrawn from mineral exploration and mining (BLM 1999, p. 6; Glennon 2010a, pers. comm.). The BLM has committed to pursuing the withdrawal of mining claims in all areas of the Special Status Plants Species ACEC (BLM 1997, p. 34).

Although occurrences of Astragalus proimanthus on BLM-administered lands are protected from the impacts of energy development, future energy development remains a potential threat to occurrences of A. proimanthus that are not located on Federal land. However, this potential threat is unlikely to rise to the level of a threat to the species as the vast majority of known occurrences (95 percent) of A. proimanthus are located on BLM-administered lands (Heidel 2010b, pers. comm.; WNDD in litt. 2010, unpaginated). Therefore, we do not consider energy development to be a threat to A. proimanthus now or in the foreseeable future.

Road Construction

Roads can destroy or modify habitat and increase human access that may lead to trampling or the introduction of nonnative invasive plants (discussed below). Additionally, road construction can lead to increased erosion, and vehicle traffic on unimproved roads can result in increased atmospheric dust and dust deposition on vegetation.

Habitat for Astragalus proimanthus has been lost at several locations due to road construction (Fertig and Welp 2001, p 16). Wyoming State Highway 1 intersects two subpopulations (Fertig and Welp 2001, p. 13). Several two-track vehicle trails are located near populations of A. proimanthus (BLM 1997, p. 199). During the summer of 1993, BLM personnel documented surface disturbance due to traffic; this was partially associated with vehicles accessing the unauthorized McKinnon Dump, which is no longer in use and has since been reclaimed (BLM 1997, p. 199).

On BLM lands, special status plant populations are closed to activities that could adversely affect them or their habitat (BLM 1997, p. 19), and the ACEC is closed to all direct surface-disturbing road construction (BLM 1997, p. 34). Future road development is a potential threat to occurrences of Astragalus proimanthus that are not on BLM-managed lands. However, future road construction does not rise to the level of a threat to A. proimanthus, because the species primarily occurs on BLM-administered lands and, therefore, is protected by the provisions in the ACEC and its designation as a special status plant species (BLM 1997, pp. 19, 34). Therefore, we do not consider road construction to be a threat to A. proimanthus now or in the foreseeable future.

Off-Road Vehicle Use

The use of ORVs is both a means of transportation and recreation in Wyoming. Approximately 35.5 percent of Wyoming's 506,000 residents use ORVs for recreational purposes (Foulke et al. 2006, p. 3). During 2004 and 2005, Sweetwater County had the fifth highest ORV permit sales in the State (Foulke et al. 2006, pp. 8-9).

The area of BLM-administered land in Sweetwater County, Wyoming, where Astragalus proimanthus occurs has not experienced the high level of ORV use seen in some other areas of Wyoming (Glennon 2010a, pers. comm.). There are no large communities nearby to support local ORV recreational activities. The closest town (within 3.2 km (2 mi) of the nearest populations of A. proimanthus) is McKinnon, with a population of 49 in 2000 (U.S. Census Bureau 2010, unpaginated). The larger communities of Green River (estimated population of 12,411 in 2009), Rock Springs (estimated population of 20,905 in 2009), and Evanston (estimated population of 11,958 in 2009) (U.S. Census Bureau 2009, unpaginated) are 78.9, 106.2, and 120.7 km (49, 66, and 75 mi) from McKinnon, respectively. There are many ORV opportunities closer to these communities than those on the BLM-administered lands near the town of McKinnon.

In addition, Astragalus proimanthus habitat is generally not attractive to ORV users. Recreational destinations in the area where A. proimanthus occurs are largely limited to a few historic sites and trails (BLM 1997, pp. 4-6). Available two-track vehicle trails provide access to most common destinations, such as water sources and hunting campsites, so that off-road access is not often necessary (Glennon 2010a, pers. comm.). Additionally, A. proimanthus occurs on slopes and ridges (Fertig and Welp 2001, p. 11) that are not conducive to ORV travel that is destination-oriented.

Finally, the ACEC is closed to ORV use (BLM 1997, p. 72). However, there are no physical barriers to keep ORVs out of the ACEC, except for in the 48.6-ha (120-ac) fenced exclosure (Glennon 2010a, pers. comm.). At other locations in southwestern Wyoming, violators of BLM and U.S. Forest Service travel restrictions on ORV use have been reported (WGFD 2010, unpaginated). The potential for impacts from illegal ORV use on BLM-administered lands is possible even within the ACEC. However, impacts from illegal ORV use are unlikely due to the low human populations in the area, the difficulty of traversing the habitats occupied by Astragalus proimanthus, and the greater likelihood of enforcement of the prohibition of ORV use within an ACEC due to critical resource concerns (BLM 1997, p. 110). Therefore, we do not consider ORV use to be a threat to A. proimanthus now or in the foreseeable future.

Range Improvements

Habitat modifications due to range improvement projects for livestock have been identified as a potential threat to Astragalus proimanthus (Marriott 1989, p. 8). However, this was prior to the designation of the ACEC that provides special protections for A. proimanthus (BLM 1997, p. 34). As stated in the Green River RMP, within the ACEC: “Livestock grazing objectives and management practices will be evaluated and, as needed, modified to be consistent with the management objectives for this area” (BLM 1997, p. 34). The plan also specifies, “Grazing systems will be designed to achieve desired plant communities and proper functioning conditions of watersheds (upland and riparian)” (BLM 1997, p. 34). Additionally, no wild horse traps will be constructed within this area (BLM 1997, p. 34). Movement of livestock between areas of known use and range improvements will be evaluated and monitored, and locations of range improvements will be modified, if necessary, to ensure that the habitat where A. proimanthus occurs will not be trampled (Glennon 2010a, pers. comm.) . The fact that populations from 1989 through 2000 were relatively stable (Fertig and Welp 2001, p. 14) suggests that range management did not adversely affect A. proimanthus populations during that time. No impacts from livestock have been noted recently (Glennon 2010a, pers. comm.). Since 1997, range management practices also are evaluated pursuant to the management objectives of the ACEC (BLM 1997, p. 19). Additionally, known locations of A. proimanthus are protected and closed to surface-disturbing activities or any disruptive activity that could adversely affect the plants or their habitat (BLM 1997, p 19). Therefore, we do not consider range improvements to be a threat to A. proimanthus now or in the foreseeable future.

Disposal Sites

Disturbance associated with garbage disposal sites (dumps) has been identified as a potential threat to Astragalus proimanthus (Marriott 1989, p. 8). Surveys conducted by the BLM in 1993 and 1994 documented disturbances to the habitat of A. proimanthus due to the presence of the McKinnon Dump (BLM 1997, p. 199). The McKinnon Dump was an illegal dump located on BLM land (Board of County Commissioners of Sweetwater County 1992, unpaginated). The BLM and Sweetwater County worked together to clean up and reclaim the McKinnon Dump (Board of County Commissioners of Sweetwater County 1992, unpaginated; BLM 1997, p. 199). Since 1997, the ACEC appears to have effectively protected A. proimanthus from surface disturbance, such as dumps, on BLM-administered lands (BLM 1997, p. 34). Therefore, we do not view disposal sites to be a threat to A. proimanthus now or in the foreseeable future.

Nonnative Invasive Plants

For general background information on nonnative invasive plants, please refer to the first paragraph of “Nonnative Invasive Plants” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

We have no evidence of impacts to Astragalus proimanthus from nonnative invasive plants. A. proimanthus grows in shallow, dry soils that support only sparse vegetation (Fertig and Welp 2001, pp. 11-12). The characteristics of its harsh habitat may explain why no nonnative invasive plants have been reported in proximity to the known occurrences. Therefore, we do not consider nonnative invasive plants to be a threat to this species now or in the foreseeable future.

Fire

We find the potential impact of wildfire to the species to be minimal due to the sparse vegetation cover in habitats occupied by Astragalus proimanthus. From 1980 through 2009 (29 years), seven wildfires occurred in the area BLM mapped as potential habitat for Astragalus proimanthus (Caldwell 2011, pers. comm.). However, no fires burned in areas with known occurrences of A. proimanthus; moreover, the total acreage burned during this 29-year period was 0.3 ha (0.7 ac) (Caldwell 2011, pers. comm.). All seven wildfires were caused by lightning strikes to isolated junipers, and only that individual tree burned (Stephenson 2011, pers. comm.). Areas of barren ground between widely spaced vegetation and low fuel loads prevent fires from spreading far beyond points of ignition (Brooks and Pyke 2002, p. 5), as the existence of adequate fuels is one of the requirements for a fire to start and continue to burn (Moritz Lab 2010, entire). Therefore, we do not consider fire to be a threat to this species now or in the foreseeable future.

Climate Change and Drought

For general background information on climate change, please refer to the first paragraphs of “Climate Change” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

Although assessing the magnitude and type of effect climate change may have on Astragalus proimanthus is complex, we believe climate change has the potential to affect the species given the predictions discussed previously of increased springtime temperatures, decreased springtime precipitation, and increased drought. The importance of yearly fluctuations in precipitation and temperature on the establishment and survival of A. proimanthus is unknown (Fertig and Welp 2001, p. 14). However, drought is not unusual or unnatural in Wyoming. Severe or extreme drought conditions occur more than 20 percent of the time over the southwestern regions of the State (Curtis and Grimes 2004, Chapter 6.2). As noted previously, monitoring data suggest that the main population along the bluffs of the Henrys Fork River was relatively stable from 1998 to 2000 (Fertig and Welp 2001, p. 14). During this same period, this species' habitat experienced drought conditions, including severe droughts (Curtis 2004, unpaginated). Although climate change may affect the duration and severity of drought in some locations, we do not have information to suggest A. proimanthus is unlikely to be able to respond to this potential stressor. Therefore, we do not consider climate change and drought to be a threat to this species now or in the foreseeable future.

Summary of Factor A

Occurrences of Astragalus proimanthus have experienced historical impacts from road development and illegal trash dumps. Additionally, seismic exploration for oil and gas occurred near one population where associated road construction may have disturbed A. proimanthus habitat, but there is no indication that plants were destroyed. Currently, the habitat disturbance due to the McKinnon dump has effectively been addressed. The special species status of A. proimanthus and the provisions in the ACEC are adequate to alleviate the threats to A. proimanthus from energy development, road construction, ORV use, range improvements, and other land uses that have the potential to disturb the habitat of A. proimanthus. Although potential threats on State and private lands may exist, such as ORV use or range improvements, only 5 percent of this species' distribution occurs on private lands, and no impacts to the species on private lands has been documented.

In summary, we note that procedural considerations for amending the Green River RMP to ensure that all individual Astragalus proimanthus plants on BLM-administered lands are protected by the Special Status Plant Species ACEC (BLM 1997, pp. 19-20, 34) are lengthy and may not accurately delineate the oscillating distributions and new discoveries of this species. However, maintenance actions may be used in certain situations including new population discoveries and species' range shifts (see Factor D: Bureau of Land Management below). Therefore, we find that the protections provided by the special status plant species designation (BLM 1997, p. 19) in combination with the protections provided by the Special Status Plant ACEC, as documented in the Green River RMP (BLM 1997, p. 34), provide effective protection to 95 percent of the population of A. proimanthus.

We conclude that the best scientific and commercial information available indicates that Astragalus proimanthus is not in danger of extinction or likely to become so within the foreseeable future because of the present or threatened destruction, modification, or curtailment of its habitat or range.

Factor B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

Astragalus proimanthus is not known to be collected for any purposes. One species of this genus, Astragalus membranaceus (Huang qi), has been used in traditional Chinese medicine for thousands of years (University of Maryland 2006, unpaginated). However, this species is native to Asia, and Astragalus species that grow in the United States do not share similar medicinal properties (University of Maryland 2006, unpaginated). We have no information to indicate that A. proimanthus is threatened by overutilization for commercial, recreational, scientific, or educational purposes.

We conclude that the best scientific and commercial information available indicates that Astragalus proimanthus is not in danger of extinction or likely to become so within the foreseeable future because of overutilization for commercial, recreational, scientific, or educational purposes.

Factor C. Disease or Predation

Disease

Astragalus proimanthus is not known to be affected or threatened by any disease. Therefore, we do not consider disease to be a threat to A. proimanthus now or in the foreseeable future.

Predation—Grazing and Herbivory

Grazing and herbivory effects on Astragalus proimanthus have not been studied. Bird or insect predation on many A. proimanthus flowers was noted on at least one occasion (Barneby 1964, p. 1154). Most occurrence reports do not mention any instances of herbivory (WNDD in litt. 2010, unpaginated; Marriot 1989, p. 16). Domestic sheep apparently do not graze A. proimanthus (Mutz 1981, p. 6), and direct impacts from grazing are thought to be unlikely due to the plant's low stature, coarse pubescence (fine, short hairs), and low palatability (Mutz 1981, p. 6; Marriott 1989, unpaginated; Fertig and Welp 2001, p. 14). Therefore, we do not consider predation to be a threat to A. proimanthus now or in the foreseeable future.

Summary of Factor C

We conclude that the best scientific and commercial information available indicates that Astragalus proimanthus is not in danger of extinction or likely to become so within the foreseeable future because of disease or predation.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

The Act requires us to examine the adequacy of existing regulatory mechanisms with respect to threats that may place Astragalus proimanthus in danger of extinction or likely to become so in the future. Existing regulatory mechanisms that could have an effect on potential threats to A. proimanthus include (1) Federal laws and regulations; (2) State laws and regulations; and (3) local land use laws, processes, and ordinances. Most (95 percent) of A. proimanthus occurs on Federal land; therefore, the discussion below focuses on Federal laws. Actions adopted by local groups, States, or Federal entities that are discretionary, including conservation strategies and guidance, are not regulatory mechanisms; however, we may discuss them in relation to their effects on potential threats to the species.

Federal Laws and Regulations

Bureau of Land Management

As discussed previously, the special status species designation and the Special Status Plant Species ACEC, as documented in the Green River RMP (BLM 1997, pp. 19, 34), have adequate provisions to effectively protect 95 percent of the population distribution of Astragalus proimanthus. An RMP, the primary management tool that implements regulatory mechanisms, goes through revisions approximately every 15 years, and a revision to the Green River RMP is anticipated by 2013 (Dana 2010b, pers. comm.). This revision has been started and the special status plant designation, based on the BLM State Directors' designation, will carry over into the newly revised RMP.

Astragalus proimanthus was designated by the BLM State Director as a BLM State-sensitive species (BLM 2010b, p. 23). The BLM focuses sensitive species management on maintaining species habitat in functional ecosystems, ensuring the species is considered in land management decisions, preventing a need to list the species under the Act, and prioritizing conservation that emphasizes habitat (BLM 2010b, p. 1). The BLM sensitive species are automatically included as special status plant species, along with candidate, threatened, and endangered plant species (BLM 1997, p. 19), and locations of special status plant species are closed to activities that could adversely affect them or their habitat (BLM 1997, p. 19). Additionally, the ACEC delineates known distributions of A. proimanthus and its essential habitat, while furthering the protection of newly discovered locations on BLM lands (BLM 1997, p. 34). The BLM conducts searches to identify additional areas where A. proimanthus may be located (BLM 1997 p. 34). In January 2011, the BLM took a maintenance action on the Green River RMP to include all newly discovered locations of A. proimanthus on BLM-administered lands in the ACEC (BLM 2011, unpaginated). Maintenance actions are based on new or changed data, and document or refine previously approved decisions incorporated into an RMP (43 CFR 1610.5-4). A maintenance action does not require formal public involvement and interagency coordination as this action is limited to refining or documenting a previously approved decision incorporated in the plan (43 CFR 1610.5-4). As a result of this maintenance action 100 percent of the known locations of A. proimanthus occurring on BLM-administered lands are protected by the ACEC (BLM 2011, unpaginated).

National Environmental Policy Act

All Federal agencies are required to adhere to the NEPA for projects they fund, authorize, or carry out. For more information about NEPA, please refer to Factor D. The Inadequacy of Existing Regulatory Mechanisms in the Five Factor Evaluation for Abronia ammophila section.

State and Local Laws and Regulations

The remaining 5 percent of the distribution of A. proimanthus occurs on State and private lands, and are not protected by regulatory mechanisms.

Summary of Factor D

The existing ACEC appears to adequately protect the majority (95 percent) of the habitat of Astragalus proimanthus. We expect that A. proimanthus and its habitat will be generally protected from direct human disturbance. We have no evidence of impacts to A. proimanthus from inadequate regulatory mechanisms.

We conclude that the best scientific and commercial information available indicates that Astragalus proimanthus is not in danger of extinction or likely to become so within the foreseeable future because of inadequate regulatory mechanisms.

Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence

Natural and manmade factors with the potential to affect Astragalus proimanthus include: (1) Small population size, (2) pollination, and (3) genetic diversity.

Small Population Size

For background information, please refer to the first paragraph of “Small Population Size” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section.

We have no evidence that the populations of Astragalus proimanthus are experiencing the problems that occur in some species with small population size. We do not have any indication that A. proimanthus was ever present on the landscape over a more extensive range. We also have no information indicating that random demographic or environmental events are a threat to the species because of its small population size. Therefore, we do not consider small population size to be a threat to A. proimanthus now or in the foreseeable future.

Pollination

Please refer to the first paragraph of “Pollination” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section for background information. Astragalus proimanthus is believed to have been historically rare, with populations appearing to be stable (Fertig and Welp 2001, p. 13). We have no information indicating that a lack of pollinators is a threat to the species. Therefore, we do not consider lack of pollinators to be a threat to A. proimanthus now or in the foreseeable future.

Genetic Diversity

For background information, please refer to the first paragraph of “Genetic Diversity” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section . We have no information indicating that a lack of genetic diversity is a threat to the species. Therefore, we do not consider lack of genetic diversity to be a threat to A. proimanthus now or in the foreseeable future.

Summary of Factor E

We have no information to suggest that Astragalus proimanthus was ever present across the landscape with a broader range. We have no indication that A. proimanthus is suffering from any problems associated with small population size. We also have no information showing that A. proimanthus is suffering from low pollination rates or reduced genetic diversity. Therefore, we conclude that the best scientific and commercial information available indicates that Astragalus proimanthus is not in danger of extinction or likely to become so within the foreseeable future because of small population size, reduced pollination, or reduced genetic diversity.

Finding

As required by the Act, we considered the five factors in assessing whether Astragalus proimanthus is threatened or endangered throughout all of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by the species. We reviewed the petition, information available in our files, other available published and unpublished information, and we consulted other Federal and State agencies.

Occurrences of Astragalus proimanthus experienced historical impacts from road development and illegal trash dumps. Additionally, seismic exploration for oil and gas occurred near one population, with no known impacts to the species. However, the provisions in the ACEC now in place are adequately alleviating any potential threats to A. proimanthus from energy development, road construction, ORV use, range improvements, and other land uses that have potential to disturb A. proimanthus and its habitat. Although potential threats on State and private lands exist, such as ORV use or range improvements, no impacts to the plants on these lands have been documented or are reasonably anticipated. We have no information to show that A. proimanthus is threatened by overutilization for commercial, recreational, scientific, or educational purposes at this time. We conclude that the best scientific and commercial information available indicates that Astragalus proimanthus is not in danger of extinction or likely to become so within the foreseeable future because of climate change, drought, nonnative invasive plants, fire, small population size, lack of pollinators, or reduced genetic diversity. We have no information regarding actual or potential adverse impacts due to overutilization, disease, inadequate regulatory mechanisms, reduced genetic diversity, or reduced pollination.

Based on our review of the best available scientific and commercial information pertaining to the five factors, we find that the threats are not of sufficient imminence, intensity, or magnitude to indicate that Astragalus proimanthus is in danger of extinction (endangered), or likely to become endangered within the foreseeable future (threatened), throughout all of its range. Therefore, we find that listing A. proimanthus as a threatened or endangered species is not warranted throughout all of its range.

Significant Portion of the Range

Having determined that Astragalus proimanthus does not meet the definition of a threatened or endangered species, we must next consider whether there are any significant portions of the range where A. rossiae is in danger of extinction or is likely to become endangered in the foreseeable future.

In determining whether Astragalus proimanthus is threatened or endangered in a significant portion of its range, we first addressed whether any portions of the range of A. proimanthus warrant further consideration. We evaluated the current range of A. proimanthus to determine if there is any apparent geographic concentration of the primary stressors potentially affecting the species including energy development, road construction, ORV use, range improvements, and other land uses. This species' small range suggests that stressors are likely to affect it in a uniform manner throughout its range. However, we found the stressors are not of sufficient imminence, intensity, magnitude, or geographically concentrated such that it warrants evaluating whether a portion of the range is significant under the Act. We do not find that A. proimanthus is in danger of extinction now, nor is likely to become endangered within the foreseeable future throughout all or a significant portion of its range. Therefore, listing A. proimanthus as threatened or endangered under the Act is not warranted at this time.

We request that you submit any new information concerning the status of, or threats to, Astragalus proimanthus to our Wyoming Ecological Services Field Office (see ADDRESSES section) whenever it becomes available. New information will help us monitor A. proimanthus and encourage its conservation. If an emergency situation develops for A. proimanthus, or any other species, we will act to provide immediate protection.

Species Information for Penstemon gibbensii

Species Description

Penstemon gibbensii is a perennial forb (herbaceous plant that is not a grass) averaging approximately 23 cm (9 in.) in height (Dorn 1990a, p. 3). Its leaves are long and narrow, often folded down the length of the mid-rib, pubescent (covered with fine, short hairs) to smooth, and typically less than 5 mm (0.2 in.) wide (Fertig and Neighbours 1996, p. 4). Populations at lower elevations are conspicuously more pubescent, possibly as an adaptation to conserve moisture in warmer habitats (Dorn 1990a, p. 6). The bright blue flower is tube-shaped, 15 to 20 mm (0.6 to 0.8 in.) long, and may appear from early June to September, depending on moisture levels (Fertig 2000d, unpaginated).

Taxonomy

Penstemon, with an estimated 271 species, is the largest plant genus endemic to North America, and the Intermountain Region represents the center of diversity (Wolfe et al. 2006, p. 1699). In the early 1970s, Robert Gibbens collected the first specimens of Penstemon gibbensii in Sweetwater County, Wyoming (Dorn 1982, p. 334). These specimens were sent to a Penstemon specialist for identification and subsequently lost (Dorn 1990a, p. 1). In 1981, Robert Dorn resurveyed the area and relocated P. gibbensii in the field (Dorn 1982, p. 334; Heidel 2009, p. 1). P. gibbensii was determined to be a new, undescribed species based on its morphology (Dorn 1982, p. 334; Fertig and Neighbours 1996, pp. 4-6). This species has been reproductively isolated for some time as each known population of P. gibbensii exhibits slight morphological and habitat differences (Dorn 1989 as cited in Fertig and Neighbours 1996, pp. 3-4).

Penstemon gibbensii is a member of the Scrophulariaceae (figwort or snapdragon) family (Dorn 1982, p. 334; Fertig and Neighbours 1996, p. 2). Similar species include Penstemon cyananthus (Wasatch beardtongue), Penstemon fremontii (Fremont's beardtongue), Penstemon saxosorum (upland beardtongue), and Penstemon scariosus (White River beardtongue) (Fertig 2000d, unpaginated). P. gibbensii, which occurs at a lower elevation than P. saxosorum, can be distinguished by stems that are pubescent nearly to the base, narrower leaves, and corollas (all the petals of the flower) that are pubescent inside and out (Dorn 1982, p. 334). P. gibbensii is more pubescent than P. cyananthus, and has much narrower leaves (Dorn 1982, p. 334). The current taxonomic status of P. gibbensii is accepted (Integrated Taxonomic Information System 2010b, unpaginated). We recognize P. gibbensii as a valid species and a listable entity.

Biology and Life History

Reproduction of Penstemon gibbensii is by seed, with no evidence of vegetative reproduction (Fertig and Neighbours 1996, p. 16). Based upon flower color and shape, this species is probably insect pollinated (Fertig and Neighbours 1996, p. 16). Bees have been seen visiting flowers at sites in Colorado and Utah (Langton 2010, pers. comm.). Fruits are oval, light-brown capsules (Fertig 2000d, unpaginated). Seeds are probably dispersed primarily by gravity or wind (Fertig and Neighbours 1996, p. 16). P. gibbensii appears to have minimal reproductive success, as evidenced by below-normal seedling numbers in most years due to dry conditions (Heidel 2009, p. 21). In 1985, 1988, and 1991, at three transects in the Cherokee Basin occurrence, 0 to 56 percent of P. gibbensii plants were seedlings (Warren in litt. 1992, Table 2). Seedling establishment is probably episodic and dependent on occasional years with adequate summer moisture (Fertig and Neighbours 1996, p. 16). P. gibbensii is able to take advantage of summer precipitation, as it is a warm-season species (Warren in litt. 1992, unpaginated).

No information was available regarding chilling requirements for seeds of P. gibbensii. However, close relatives (i.e., Penstemon cyananthus, Penstemon fremontii, and Penstemon scariosus) have seeds that are largely dormant at harvest and require a long chilling period prior to germination (Meyer and Kitchen 1994, p. 354). These species have evolved seed germination mechanisms that permit the carryover of seeds between years as a persistent seed bank, which maximizes the probability of seedling survival in favorable years (Meyer and Kitchen 1994, p. 363). Recognizing the similarities between these Penstemon species and their climatic conditions, we assume that P. gibbensii also requires a chilling period and has a persistent seed bank.

Habitat

Penstemon gibbensii occurs in a cold steppe climate on barren shale or sandy-clay slopes (Dorn 1990a, p. 6). Habitat is often located on steep upper or middle slopes eroding below a more resistant caprock (Heidel 2009, p. 13). Slopes are generally 20 to 30 degrees and predominately south- or west-facing (Dorn 1990a, p. 8). These conditions reduce percolation (water seeping into the ground) and increase evaporation (Heidel 2009, p. 20). P. gibbensii has been reported at elevations from 1,634 to 2,347 m (5,360 to 7,700 ft) (Dorn 1990a, p. 5; CNHP 2010a, unpaginated). Soils are typically highly erodible, with low nutrient levels, low soil moisture, and high selenium content (Spackman and Anderson 1999, p. 3).

Biological soil crusts are well-developed in Penstemon gibbensii habitat in Colorado and Utah, but were not noted at any sites in Wyoming (Heidel 2009, p. 14). Biological soil crusts are commonly found in semiarid and arid environments such as the Great Basin and Colorado Plateau, and are formed by a community of living organisms that can include cyanobacteria, green algae, microfungi, mosses, liverworts, and lichens (USGS 2006, unpaginated). These crusts provide many positive benefits for the larger biotic community including decreased erosion, improved water infiltration, increased seed germination, and improved plant growth (Spackman and Anderson 1999, p 3; USGS 2006, p. 2).

Penstemon gibbensii exploits a largely barren, challenging environment (Dorn 1990a, p. 3). This species is generally not tolerant of competition from other species or other Penstemon plants; individual plants are usually spaced one to several meters (3 or more ft) apart (Dorn 1990a, pp. 8-9). Total vegetative cover is typically 5 to 10 percent (Fertig 2000, p. 2). Associated species include Elymus spicatus (bluebunch wheatgrass), Achnatherum hymenoides (Indian ricegrass), Herperostipa comata (needle-and-thread grass), Eriogonum brevicaule (shortstem wild buckwheat), Eremogone hookeri (Hooker's sandwort), and Minuartia nuttallii (Nuttall's stitchwort) (Heidel 2009, p. 13). Adjacent vegetative communities may include pinyon-juniper woodlands, sagebrush shrublands, or greasewood-saltbush shrublands (Dorn 1990a, p. 9).

Distribution

Penstemon gibbensii is a regional endemic, with a range that includes Carbon and Sweetwater Counties in Wyoming, Moffat County in Colorado, and Daggett County in Utah (Dorn 1990a, p. 6; Heidel 2009, p. 31). P. gibbensii was not recognized as a new species until 1981 (Dorn 1982, p. 334; Fertig and Neighbours 1996, pp. 4-6). Consequently, its historical range is unknown. However, P. gibbensii was possibly always uncommon (Heidel 2009, pp. 5, 8). The species is currently known from nine occurrences including: Cherokee Basin, Sand Creek, Flat Top Mountain, T84N R18W, Willow Creek, and Red Creek Rim in Wyoming; Spitzie Draw and Sterling Place in Colorado; and Dagget County, Utah. These nine occurrences are spread across 193 km (120 mi) and occupy approximately 109 ha (270 ac) in Wyoming, 10 ha (25 ac) in Colorado, and 2 ha (5 ac) in Utah (Heidel 2009, p. 31). Three of the six Wyoming occurrences and the Colorado and Utah occurrences are within 5 to 8 km (3 to 5 mi) of each other (Heidel 2009, p. 9). In Wyoming, surveys for additional occurrences have been conducted in over 100 sections (each section is 259 ha (640 ac)), primarily along the Carbon-Sweetwater County line (Heidel 2009, p. 12). Additional potential habitat also has been searched in Moffat County, Colorado, and in Daggett County, Utah; no new populations have been found in these areas (Dorn 1990a, p. 6; Spackman and Anderson 1999, p. 31).

Most known Penstemon gibbensii (approximately 77 percent) occur on State and Federal land. All Wyoming occurrences, with the exception of the T84N R18W occurrence and a small portion of the Sand Creek occurrence are on land managed by BLM (Heidel 2009, p. 27). The Nature Conservancy (TNC) manages the T84N R18W occurrence, which is on State and private land (Heidel 2009, p. 31). A small portion of the Sand Creek occurrence also is on State land (Heidel 2009, p. 27). In Colorado, the Spitzie Draw occurrence is on Browns Park National Wildlife Refuge (NWR) (managed by the Service) and BLM land, and the Sterling Place occurrence is on BLM land. The Daggett County, Utah, occurrence is on State land (Heidel 2009, p. 27). Management responsibilities are described in Table 2 below.

Abundance

Table 2 presents available information regarding the known occurrences of Penstemon gibbensii. The plant numbers and occupied habitat do not sum to the exact current total due to slight differences between references. Most estimates are based on walking surveys through occupied habitat; two sites (Cherokee Basin and Flat Top Mountain) also have permanent transects for trend monitoring (Heidel 2009, Appendix B).

Table 2—Known Occurrences of Penstemon Gibbensii

Species occurrence (year identified)	Estimated plant numbers (year surveyed)	Occupied habitat	Management
Cherokee Basin, WY (1981)	450 (1985)	6.2 ha (15.2 ac)	BLM-Rawlins Field Office.
	1,400 (1988) 2,766 (1991) 1,000 (1995) 50-100 (2007)
Sand Creek, WY (1987)	2,000 (1989) 1,900-2,000 (1995) 3,000 (2005)	48.1 ha (118.7 ac)	BLM-Rawlins Field Office and State of WY.
Flat Top Mountain, WY (1987)	300 (1989) 1,000-1,200 (1995) 300 (2008)	7.2 ha (17.9 ac)	BLM-Rawlins Field Office.
T84N R18W, WY (1997)	4,500-5,000 (1999) 500-1,000 (2008)	28.8 ha (71.2 ac)	TNC.
Willow Creek, WY (2004)	2,200 (2008)	15.6 ha (38.5 ac)	BLM-Rawlins Field Office.
Red Creek Rim, WY (2008)	120 (2008)	3.3 ha (8.1 ac)	BLM-Rawlins Field Office.
Spitzie Draw, CO (1982)	263 (2009)	~5 ha (12 ac)	Service-Browns Park NWR. BLM-Little Snake Field Office.
Sterling Place, CO (1984)	656 (2010)	~4 ha (9 ac)	BLM-Little Snake Field Office.
Daggett County, UT (1989)	300 (2010)	5 ha (12 ac)	State of UT.
Current Total	~11,000-14,000	~122 ha (300 ac)
Table 2 References: Heidel 2009, pp. 22, 31; CNHP in litt. 2009a, p. 2; in litt. 2009b, p. 2; in litt. 2010a, p. 2.

The Colorado Natural Heritage Program (CNHP) has designated Penstemon gibbensii as a plant species of special concern (CNHP 2010b, unpaginated). The WYNDD also has designated P. gibbensii as a plant species of concern (Heidel 2007, p. 18). The Utah Native Plant Society ranks P. gibbensii as a rare plant of “extremely high priority” (Utah Rare Plants 2010, unpaginated). These designations are typically based on TNC's natural heritage State rank. P. gibbensii is ranked S1 in all three States because of its extreme rarity. These designations indicate that particular consideration may be taken by the States with regard to management decisions potentially affecting P. gibbensii, but do not result in any regulatory protection for the species.

Trends

Long-term population trend data for Penstemon gibbensii is not available. Short-term trends can be examined at four of the nine occurrences, where population estimates are available for more than 1 year (see Table 1). Only a single population estimate is available from the two most recently discovered sites in Wyoming and the three sites in Colorado and Utah. Short-term trends for the three Wyoming populations of P. gibbensii that have been surveyed more frequently were described as stable to slightly increasing in 2000; this was attributed to favorable climatic conditions in the preceding years (Fertig 2000d, unpaginated). Since 2000, populations appear to be stable to increasing at the Sand Creek occurrence and declining at the other three Wyoming sites. Seedling establishment is probably episodic (occurring at irregular intervals) and dependent on rare years of adequate summer moisture (Fertig and Neighbours 1996, p. 16; Heidel 2009, p. 22). The resultant uneven survival of seedlings may account for short-term population fluctuations in this species (Fertig and Neighbours 1996, p. 16). Survey results from 1995 may represent peak population estimates due to ideal climatic conditions, rather than mean or low estimates (Heidel 2009, p. 23). Overall, there is not enough information to conclusively determine rangewide trends for the species.

Five Factor Evaluation for Penstemon gibbensii

Information pertaining to Penstemon gibbensii in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

The following potential factors that may affect the habitat or range of Penstemon gibbensii are discussed in this section: (1) Energy development, (2) roads, (3) trampling, (4) nonnative invasive plants, and (5) climate change and drought.

Energy Development

As previously discussed, many activities associated with energy development can destroy or modify habitat. Since 1989, energy exploration has increased in the Wyoming portion of the range of Penstemon gibbensii (Heidel 2009, p. 28). However, most occurrences of P. gibbensii are on unstable slopes that are unlikely to be developed for roads, pipelines, or well pads (Fertig and Neighbours 1996, pp. 19-20; Heidel 2009, p. 28). However, the Sand Creek occurrence, which is on flatter terrain, is located in an active oil and gas field, with one pipeline passing through a subpopulation of P. gibbensii and an accompanying access road intersecting a limited portion (does not impact a lot of potential habitat of P. gibbensii) of another subpopulation (Heidel 2009, p. 43). A well pad also is located nearby (Heidel 2009, p. 28).

While this development has destroyed some P. gibbensii habitat, some of the land disturbances at Sand Creek have provided additional habitat by exposing appropriate substrate for plant establishment (Dorn 1990a, p. 13; Heidel 2009, p. 43). Two pipelines have been laid at the Willow Creek occurrence, one adjacent to a subpopulation and the other through a subpopulation that may have destroyed plants (Heidel 2009, p. 55). However, these developments dissect limited areas of occupied habitat at Willow Creek, and the current impacts are likely not severe as most of P. gibbensii is located on unstable slopes (Heidel 2009, p. 28). The sale of leases for oil and gas development continues in Carbon and Sweetwater Counties in Wyoming (BLM 2010c, pp. 51-63, 75-77, 83). Consequently, further energy development is possible within the foreseeable future; however, potential impacts from it are unknown.

In addition to oil and gas development, uranium is mined near the Red Creek Rim occurrence (Heidel 2009, p. 28). No impacts to Penstemon gibbensii have been documented as a result of uranium mining. Sub-bituminous coal underlies portions of the range of Penstemon gibbensii; however, this coal is not suitable for strip mining (Heidel 2009, p. 28). Oil shale rock also is present (Heidel 2009, p. 28). Wind energy development and gravel quarry development are possible, but have not occurred to date (Heidel 2009, p. 28).

In conclusion, minimal impacts to Penstemon gibbensii were noted from oil and gas development, no impacts have been documented from uranium mining, and the other types of development are currently only speculative. Therefore, we do not consider energy development to be a threat to P. gibbensii now or in the foreseeable future.

Roads

Roads can destroy or modify habitat. Roads also can increase access, leading to trampling or the introduction of nonnative invasive plants (discussed below). A few roads cross or are adjacent to occurrences of Penstemon gibbensii. As mentioned under energy development, one access road intersects a limited portion of a subpopulation at the Sand Creek occurrence, but also may provide additional habitat as P. gibbensii is able to colonize the margins of disturbed areas (Heidel 2009, pp. 28, 43). Another road crosses the edge of the Willow Creek occurrence (Heidel 2009, p. 43). At the Spitzie Draw occurrence, State Route 318 passes within 0.4 km (0.25 mi), and an access road passes within 200 m (656 ft) (Spackman and Anderson 1999, p. 23). State Route 318 also passes within 50 m (164 ft) of a portion of the Sterling Place occurrence (CNHP in litt. 2010a, p. 3). A steep road is adjacent to the Flat Top Mountain occurrence (Fertig and Neighbours 1996, p. 35). The Flat Top Mountain road is experiencing erosion that, if unchecked, could eventually encroach on P. gibbensii occupied habitat (Fertig and Neighbours 1996, p. 35; Heidel 2009, p. 59). We have no information on the building of future roads, but do not anticipate any based on the topography and isolated nature of most of P. gibbensii' s distribution. Although some roads occur in and near the habitat of P. gibbensii, we do not have any indication that they have significant negative effects to the species. Additionally, we have no information on dust or levels of travel on these roads impacting P. gibbensii or its habitat.

In conclusion, only minimal impacts to Penstemon gibbensii were noted from roads. Therefore, we do not consider roads to be a threat to P. gibbensii now or in the foreseeable future.

Trampling

Trampling by livestock, ORVs, or human foot traffic can destroy plants and increase soil erosion, especially at sites with steep, loose soils. It has been mentioned as a potential concern at seven of nine occurrences (Warren in litt. 1992, unpaginated; Fertig and Neighbours 1996, p. 20; Spackman and Anderson 1999, p. 31; Fertig 2000d, unpaginated; Heidel 2009, p. 28; CNHP in litt. 2010a, p. 4). Penstemon gibbensii may colonize the margins of disturbed areas, but cannot become established within an area of active use (Heidel 2009, p. 28). Soil disturbance has been noted at the Sterling Place occurrence from cattle bedding down (CNHP in litt. 2010a, p. 4) and at the Cherokee Basin occurrence from humans (Warren in litt. 1992, unpaginated). Survey activities at Cherokee Basin in 1988 left distinct footprints that were still distinguishable in places 3 years later (Warren in litt. 1992, unpaginated).

As stated above, biological soil crusts have been noted at occurrences in Colorado and Utah, but not in Wyoming (Spackman and Anderson 1999, pp. 22, 26; Heidel 2009, pp. 14, 20; CNHP 2010a, unpaginated; in litt. 2010d, p. 2). The absence of biological soil crusts in Wyoming may reflect the effects of trampling from historically heavy sheep (Ovis aries) grazing (Heidel 2009, p. 27).

In summary, trampling is a potential concern at most sites and has been documented at two sites. However, we have no information regarding whether any Penstemon gibbensii plants were actually trampled. Additionally, P. gibbensii is able to colonize the margins of disturbed habitats and is able to live in Wyoming where there is no evidence of biological crusts in their habitat. We have no information indicating that trampling is a threat to the species. Therefore, we do not consider trampling to be a threat to P. gibbensii now or in the foreseeable future.

Nonnative Invasive Plants

For general background information on nonnative invasive plants, please refer to the first paragraph of “Nonnative Invasive Plants” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

Encroachment of nonnative invasive plants may potentially impact Penstemon gibbensii. However, P. gibbensii is typically restricted to bare, sparsely vegetated slopes with large areas of exposed soil where competition with other plant species, including nonnative invasive species, is minimal (Heidel 2009, p. 26). Nonnative invasive plant numbers are generally low in, and adjacent to, P. gibbensii occurrences, and are most common near roads (Spackman and Anderson 1999, p. 23; Heidel 2009, p. 29). Alyssum desertorum (desert madwort) has been documented at or near Cherokee Basin and Red Creek Rim; Bromus tectorum, at or near Cherokee Basin, Red Creek Rim, Sand Creek, Sterling Place, and Dagget County; Halogeton glomeratus (halogeton), at or near Cherokee Basin, Red Creek Rim, Spitzie Draw, and Sterling Place; and Salsola australis (Russian thistle), at or near Spitzie Draw and Sterling Place (Heidel 2009, p. 29; CNHP 2010a, p. 2; in litt 2010d, p. 2). These species have been occasionally noted for at least 10 years (Spackman and Anderson 1999, pp. 23, 27; Heidel 2009, p. 29; CNHP 2010a, unpaginated; CNHP 2010e, unpaginated), but there is no evidence of increasing trends regarding their numbers at these sites. There is no evidence that any of these nonnative invasive species have had a negative impact on P. gibbensii.

Nonnative invasive plants are present at or near six occurrences of Penstemon gibbensii. However, their numbers are generally low, and there is no evidence that they are problematic. We have no information indicating that nonnative invasive plants are a threat to the species. Therefore, we do not consider nonnative invasive plants to be a threat to P. gibbensii now or in the foreseeable future.

Climate Change and Drought

For general background information on climate change, please refer to the first paragraphs of “Climate Change” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

Plant species with restricted ranges that also are climatically limited may experience population declines as a result of climate change (Schwartz and Brigham 2003, p. 11). Whether Penstemon gibbensii would be positively impacted by an increase in barren land due to drought that provided potential habitat, or negatively impacted by a loss of current marginal habitat, cannot be predicted. Dorn (1990a, p. 6) noted that P. gibbensii has fewer and smaller flowers than most species of Penstemon and hypothesized that this species may have once grown under moister conditions and could be in long-term decline due to climatic change. However, no additional supporting data were provided. He also noted that populations at lower, hotter elevations are more pubescent, a possible adaptation to conserve moisture (Dorn 1990a, p. 6).

Drought is a natural and common phenomenon within the range of Penstemon gibbensii (Dorn 1990a, p. 6). Average annual precipitation ranges from approximately 26 cm (10 in.) at Wyoming occurrences to about 41 cm (16 in.) at Colorado and Utah occurrences (Heidel 2009, pp. 19-20). As discussed above, P. gibbensii appears to have minimal reproductive success in most years because of dry conditions, but responds favorably to late-summer moisture that occurs infrequently (Fertig and Neighbours 1996, p. 16; Heidel 2009, p. 22). Penstemon gibbensii is a warm-season plant that remains succulent through the summer; therefore, it can take advantage of summer thunderstorms after other species have stopped growing or completed their life cycle (Warren in litt. 1992, unpaginated). Morphological adaptations discussed above (pubescent, narrow leaves in hotter climes) also indicate that the species is not limited by variations in the regional climate to a great degree.

We believe that Penstemon gibbensii has evolved to adapt to recurring drought conditions. Short-term population fluctuations, in response to varying climatic conditions from year to year, appear to be typical for the species. We have no information indicating that climate change or drought is a threat to the species. Therefore, we do not consider climate change or drought to be a threat to P. gibbensii now or in the foreseeable future.

Summary of Factor A

Two occurrences (Sand Creek and Willow Creek) have experienced minor impacts from energy development. Five occurrences (Sand Creek, Willow Creek, Spitzie Draw, Sterling Place, and Flat Top Mountain) have roads that are nearby or cross a portion of the occurrence. The Sand Creek occurrence, which appears to be experiencing more disturbances from energy development and road usage than the other sites, has had an increase in P. gibbensii numbers according to survey results despite these disturbances. We are not aware of any future energy development projects being planned in or near any of the P. gibbensii occurrences. Furthermore, the topography at most occurrences does not lend itself to energy development or road construction (Fertig and Neighbours 1996, pp. 19-20; Heidel 2009, p. 28). Therefore, we do not anticipate substantial habitat disturbance in the future. Trampling has been documented at two sites, but there is no information indicating that plants have been destroyed. Nonnative invasive plants are present at or near six occurrences of P. gibbensii. However, nonnative invasive plant numbers are generally low, and there is no evidence that they are problematic. Climate change and drought could potentially modify habitat at all occurrences. However, the species appears to have adapted to recurrent drought and variations in climatic conditions. Adverse impacts due to habitat destruction, modification, or curtailment appear minimal at the present time.

We conclude that the best scientific and commercial information available indicates that Penstemon gibbensii is not in danger of extinction or likely to become so within the foreseeable future because of the present or threatened destruction, modification, or curtailment of its habitat or range.

Factor B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

We are not aware of any adverse impacts to Penstemon gibbensii from overutilization for commercial, recreational, scientific, or educational purposes at this time. We conclude that the best scientific and commercial information available indicates that P. gibbensii is not in danger of extinction or likely to become so within the foreseeable future because of overutilization for commercial, recreational, scientific, or educational purposes.

Factor C. Disease or Predation

Disease

We are not aware of any adverse impacts to Penstemon gibbensii from disease at this time. Therefore, we do not consider disease to be a threat to P. gibbensii now or in the foreseeable future.

Predation—Grazing and Herbivory

Penstemon gibbensii is relatively succulent and may be grazed by mule deer (Odocoileus hemionus), pronghorn (Antilocapra americana), domestic cattle (Bos taurus), and other herbivores during late summer when green vegetation is sparse (Heidel 2009, p. 26). Currently, there is no sheep grazing in the habitat of P. gibbensii (Fertig and Neighbours 1996, p. 19); as discussed above, historical sheep use may have been heavy in Wyoming (Heidel 2009, p. 14). Grazing appears to be restricted almost entirely to flowering stems, which could impact seed production, seed bank replenishment, and long-term viability (Fertig and Neighbours 1996, p. 19). However, steep slopes, unstable footing, and overall low forage production in P. gibbensii habitat may limit use by wildlife and livestock (Warren in litt. 1992, unpaginated; Heidel 2009, p. 27).

Grazing intensity often varies between years and between sites and does not appear to negatively affect Penstemon gibbensii. At the Spitzie Draw occurrence, variable levels of browsing by mule deer were noted in 2009 (CNHP in litt. 2009a, unpaginated; in litt. 2009b, unpaginated), but little evidence of grazing or browsing was found in 2010 (CNHP in litt. 2010c, p. 2). At the Sterling Place occurrence, there was little evidence of damage to P. gibbensii from mule deer or elk (Cervus canadensis), but there was moderate to heavy cattle grazing (CNHP in litt. 2010a, p. 2). At the Daggett County occurrence, there was little evidence of any grazing (CNHP in litt. 2010b, p. 2). P. gibbensii numbers at Flat Top Mountain were high in 1995 and low in 2008 (see Table 2). However, plants experienced low levels of herbivory (approximately 5 percent) in both years (Heidel 2009, p. 24). Cattle grazing also was observed at the Sand Creek occurrence in 2005 (Heidel 2009, p. 43).

The Cherokee Basin occurrence is the only site that is fenced. In 1985, the BLM fenced 95 percent of the site to exclude cattle, and 5 percent or less was left unfenced (Warren in litt. 1992, unpaginated). The allotment, an area larger than the P. gibbensii occurrence, was monitored to compare the effects of grazing pressure (Warren in litt. 1992, unpaginated). In 1992, the overall level of livestock use in the allotment was low to moderate, the range was in good to excellent condition with an improving trend, and a reduced stocking rate was not recommended (Warren in litt. 1992, unpaginated). The Cherokee Basin exclosure has been critical in ruling out grazing as the cause of recent declines at this occurrence, where plant numbers have declined since the early 1990s (see Table 1) (Heidel 2009, p. 30).

No specific information regarding grazing is available for the T84N R18W, Willow Creek, or Red Creek Rim occurrences, other than general observations regarding the potential for grazing by livestock and wildlife.

Grazing intensity is variable between years and sites, but appears to have minimal impact to Penstemon gibbensii, possibly because of steep slopes, unstable footing, and overall low forage production in the species' habitat. Fluctuations in plant numbers have occurred at Flat Top Mountain, despite consistent levels of grazing, and at Cherokee Basin, in the absence of grazing, which supports the conclusion that grazing causes minimal adverse impacts to P. gibbensii. Therefore, we do not consider grazing to be a threat to P. gibbensii now or in the foreseeable future.

Summary of Factor C

We have no evidence of adverse impacts to Penstemon gibbensii from disease. P. gibbensii is relatively succulent and may be grazed by both wildlife and livestock, particularly in late summer when most sympatric vegetation has dried. However, the typical habitat of P. gibbensii (steep slopes, loose substrate, and sparse vegetative cover) appears to limit heavy grazing at most sites and minimize impacts from grazing.

We conclude that the best scientific and commercial information available indicates that Penstemon gibbensii is not in danger of extinction or likely to become so within the foreseeable future because of disease or predation.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

The Act requires us to examine the adequacy of existing regulatory mechanisms with respect to threats that may place Penstemon gibbensii in danger of extinction or likely to become so in the future. Existing regulatory mechanisms that could have an effect on potential threats to P. gibbensii include (1) Federal laws and regulations; (2) State laws and regulations; and (3) local land use laws, processes, and ordinances. Actions adopted by local groups, States, or Federal entities that are discretionary, including conservation strategies and guidance, are not regulatory mechanisms; however, we may discuss them in relation to their effects on potential threats to the species.

Federal Laws and Regulations

Bureau of Land Management

Most known Penstemon gibbensii occurrences are on BLM land (see Table 2). The BLM recognizes P. gibbensii as a sensitive species throughout its range (Heidel 2009, p. 6). Sensitive species designation requires that the species is: (1) Native, (2) at risk or populations trending downward throughout all or a significant portion of its range, and (3) dependent on special or unique habitat on BLM lands (Sierra 2009, in litt.). As discussed above, these species are managed to promote their conservation and minimize the likelihood and need for listing under the Act. The oldest known occurrence at Cherokee Basin was fenced by the BLM for added protection (see Factor C). Four occurrences (Cherokee Basin, Flat Top Mountain, Spitzie Draw, and Sterling Place) were recommended by the BLM for designation as ACECs (Heidel 2009, pp. 30-31). However, the final records of decision for the Rawlins RMP in Wyoming and the Little Snake River RMP in Colorado did not designate any of these occurrences as ACECs (Heidel 2009, pp. 30-31). Designation as an ACEC would have protected these sites from surface disturbances associated with energy and road development. Nevertheless, as discussed under Factor A, additional energy development is not anticipated, and the steep slopes found at these sites render them ill-suited for most road construction.

National Wildlife Refuge

Browns Park National Wildlife Refuge maintains a variety of native habitats and wildlife, with emphasis on migratory birds, threatened and endangered species, and species of special concern. The NWR has a portion of one occurrence of Penstemon gibbensii, which is protected by refuge regulations that require all vehicles to remain on developed roads and prohibit the collection, possession, or destruction of any plant (Service 2010, unpaginated).

National Environmental Policy Act

Most known Penstemon gibbensii (approximately 77 percent) occur on Federal and State land (Heidel 2009, pp. 22, 27). All Federal agencies are required to adhere to the NEPA for projects they fund, authorize, or carry out. Please refer to the NEPA discussion under Factor D. The Inadequacy of Existing Regulatory Mechanisms in the Five Factor Evaluation for Abronia ammophila section for additional information.

State Regulatory Mechanisms

The Penstemon gibbensii occurrence in Daggett County, Utah, and a portion of the T84N R18W, Wyoming occurrence are on State lands. P. gibbensii is designated as a rare plant in Utah and a species of concern in Wyoming (WNDD 2007, p. 2; Utah Rare Plants 2010, p. 2). These designations signify recognition by the States regarding the rarity of the species, but do not confer any specific protection.

Local Land Use Laws, Ordinances, and Contracts

The Nature Conservancy

TNC has a conservation easement on the private land portion of the T84N R18W occurrence that protects the area from many development activities (Heidel 2009, p. 31). This is a permanent easement that includes surface rights, but not mineral rights (Browning 2010, pers. comm.).

Summary of Factor D

We have no evidence of impacts to Penstemon gibbensii from inadequate regulatory mechanisms. All but a portion of one occurrence are on Federal or State lands. The portion on private land is largely protected by a conservation easement. Seven of the nine known occurrences are managed all or in part by BLM, which promotes the conservation of sensitive species and minimizes the likelihood and need for their listing under the Act. The Service has refuge regulations that protect P. gibbensii occurring on their lands.

We conclude that the best scientific and commercial information available indicates that Penstemon gibbensii is not in danger of extinction or likely to become so within the foreseeable future because of inadequate regulatory mechanisms.

Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence

Natural and manmade factors with the potential to affect Penstemon gibbensii include: (1) Small population size, (2) pollination, and (3) genetic diversity.

Small Population Size

For general background information on small population size, please refer to the first paragraph of “Small Population Size” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section.

No information exists regarding the historical range or population numbers of Penstemon gibbensii, but experts familiar with the species conclude that it was likely historically rare (Dorn 1990a, p. 6; Fertig and Neighbours 1996, p. 4; Spackman and Anderson 1999, p. 32; Heidel 2009, p. 5). P. gibbensii is a local endemic that has evolved to exploit a barren, erodible habitat (Dorn 1990a, p. 3). The slight morphological differences, different substrates, and widely separated distribution suggest that the species is a paleoendemic (has been in existence for a long period of time in a single region) (Dorn 1990a, p. 6; Heidel 2009, p. 5). Detailed descriptions of the species' abundance and trends are provided under the Abundance and Trends sections for this species. No occurrences have been extirpated since the species was first identified in 1981, indicating some resilience to perturbation.

New occurrences of Penstemon gibbensii continue to be documented including Willow Creek in 2004 and Red Creek Rim in 2008 (Heidel 2009, p. 9). P. gibbensii is presently known from nine occurrences that span a distance of 193 km (120 mi) (Heidel 2009, p. 31). Some potentially suitable areas have not yet been surveyed (Heidel 2009, pp. 10-12), and more occurrences may be located.

Penstemon gibbensii is likely a historically rare plant that has nonetheless persisted. Existing sites are monitored, and surveys have located new occurrences. No occurrences have been extirpated. We have no information indicating that random demographic or environmental events are a threat to the species because of its small population size. Therefore, we do not consider small population size to be a threat to P. gibbensii now or in the foreseeable future.

Pollination

Penstemons are pollinated by a variety of insects and hummingbirds, but most commonly by insects from the Order Hymenoptera (Wolfe et al. 2006, pp. 1699, 1709). Bees have been seen visiting flowers at sites in Colorado and Utah (Langton 2010, pers. comm.). As discussed above, pollinators may regard small populations as inferior or unreliable food sources, leading to low visitation rates (Oostermeijer 2003, p. 23). Low visitation rates may be more of a concern in currently rare species that were historically abundant (Brigham 2003, p. 84). However, as identified above, Penstemon gibbensii is believed to have been historically rare (Dorn 1990a, p. 6; Fertig and Neighbours 1996, p. 4; Spackman and Anderson 1999, p. 32; Heidel 2009, p. 5).

Only very limited information is available regarding pollination of Penstemon gibbensii. However, we have no information indicating that poor pollination is a threat to the species. Therefore, we do not consider lack of pollinators to be a threat to P. gibbensii now or in the foreseeable future.

Genetic Diversity

For general background information on genetic diversity, please refer to the first paragraph of “Genetic Diversity” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section .

The risk of negative consequences to rare plants from reduced genetic diversity varies (Brigham 2003, p. 88). Penstemon gibbensii is one of several plant species being studied in a comparative population genetics analysis. Initial results from a study of two Wyoming populations document high variation of DNA sequences within populations examined to date; however, between-population differentiation analysis has not yet been conducted (Heidel 2009, p. 5). These results are preliminary and limited in scope, but indicate that an adequate level of genetic diversity exists in these populations. Genetic exchange could be possible as three of the Wyoming occurrences and the three occurrences in Colorado and Utah are within 5 to 8 km (3 to 5 mi) of each other (Heidel 2009, p. 9).

Only very limited information regarding the genetic diversity exhibited by Penstemon gibbensii is available. However, we have no information indicating that a lack of genetic diversity is a threat to the species. Therefore, we do not consider reduced genetic diversity to be a threat to P. gibbensii now or in the foreseeable future.

Summary of Factor E

We conclude that the best scientific and commercial information available indicates that Penstemon gibbensii is not in danger of extinction or likely to become so within the foreseeable future because of small population size, reduced pollination, or reduced genetic diversity.

Finding

As required by the Act, we considered the five factors in assessing whether Penstemon gibbensii is threatened or endangered throughout all of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by the species. We reviewed the petition, information available in our files, other available published and unpublished information, and we consulted other Federal and State agencies.

Five occurrences (Sand Creek, Willow Creek, Spitzie Draw, Sterling Place, and Flat Top Mountain) have experienced some minimal adverse impacts to the habitat of Penstemon gibbensii due to oil and gas development and road construction. The topography at most occurrences does not lend itself to energy development or road construction; therefore, we do not anticipate substantial habitat disturbance in the future. All occurrences could experience increased temperatures and precipitation changes from climate change. Whether this would result in a net gain or net loss in potential habitat cannot be predicted. However, differing morphological adaptations at the various occurrences indicate that the species can adapt to variable climate conditions.

Five occurrences (Sand Creek, Flat Top Mountain, Spitzie Draw, Sterling Place, and Daggett County) have documentation of grazing. However, the typical habitat of P. gibbensii (steep slopes, loose substrate, and sparse vegetative cover) appears to limit heavy grazing. Two occurrences (Cherokee Basin and Sterling Place) have experienced some trampling by humans and livestock. However, we are not aware of any loss of P. gibbensii at either of these sites from trampling.

All occurrences experience drought as a natural and regular phenomenon, which likely results in short-term population fluctuations. However, P. gibbensii has evolved to adapt to recurring drought conditions. Six occurrences (Cherokee Basin, Sand Creek, Red Creek Rim, Spitzie Draw, Sterling Place, and Daggett County) have nonnative invasive plants at or near the site. However, the typical habitat of P. gibbensii is sparsely vegetated slopes with large areas of bare soil where competition with other plant species, including nonnative invasive plants, is minimal.

All occurrences have relatively small populations. However, P. gibbensii is considered historically rare. No occurrences have been extirpated since the species was first identified, and new occurrences continue to be documented. We have no information regarding actual or potential adverse impacts due to overutilization, disease, inadequate regulatory mechanisms, reduced genetic diversity, or reduced pollination.

Based on our review of the best available scientific and commercial information pertaining to the five factors, we find that the threats are not of sufficient imminence, intensity, or magnitude to indicate that Penstemon gibbensii is in danger of extinction (endangered), or likely to become endangered within the foreseeable future (threatened), throughout all of its range. Therefore, we find that listing P. gibbensii as a threatened or endangered species is not warranted throughout all of its range.

Significant Portion of the Range

Having determined that Penstemon gibbensii does not meet the definition of a threatened or endangered species, we must next consider whether there are any significant portions of the range where P. gibbensii is in danger of extinction or is likely to become endangered in the foreseeable future.

In determining whether Penstemon gibbensii is threatened or endangered in a significant portion of its range, we first addressed whether any portions of the range of P. gibbensii warrant further consideration. We evaluated the current range of P. gibbensii to determine if there is any apparent geographic concentration of the primary stressors potentially affecting the species including energy development, roads, climate change, grazing, trampling, drought, nonnative invasive plants, and small population size. P. gibbensii is likely a historically rare endemic plant known from nine occurrences spanning a distance of 193 km (120 mi) (Heidel 2009, p. 31). This species' small range suggests that stressors are likely to affect it in a uniform manner throughout its range. All stressors occur at or near most sites, with the exception of energy development, which has been documented at or near three occurrences. However, the sale of oil and gas leases is ongoing; consequently, it is a potential stressor at most sites. Effects to P. gibbensii from these stressors are not disproportionate in any portion of the species' range. As we explained in detail in our analysis of the status of the species, none of the stressors faced by the species are sufficient to place it in danger of extinction now (endangered) or in the foreseeable future (threatened). Therefore, no portion is likely to warrant further consideration, and a determination of significance is not necessary.

We do not find that Penstemon gibbensii is in danger of extinction now, nor is it likely to become endangered within the foreseeable future throughout all or a significant portion of its range. Therefore, listing P. gibbensii as threatened or endangered under the Act is not warranted at this time.

We request that you submit any new information concerning the status of, or threats to, Penstemon gibbensii to our Wyoming Ecological Services Field Office (see ADDRESSES section) whenever it becomes available. New information will help us monitor P. gibbensii and encourage its conservation. If an emergency situation develops for P. gibbensii, or any other species, we will act to provide immediate protection.

Species Information for Boechera pusilla

Species Description

Boechera pusilla (Fremont County rockcress or small rockcress) is a perennial herb with several decumbent (lying down), unusually slender stems up to 17 cm (6.7 in.) long. The plant has basal leaves that are linear (at least 10 times longer than wide) and erect, with relatively sparse forked spreading hairs located on the leaves. Plants generally have three to five stem leaves that are nonclasping (not encircling the stem) and widely spaced. Flowers are small, light lavender, four-petaled, and blossom from May to mid-June. The fruits, which are present from mid-June to July, are hairless linear siliques (narrow elongated seed capsule) that spread at right angles from the drooping main stem on pedicels (small stalks) less than 3 mm (0.12 in.) (Marriott 1986, p. 3; Dorn 1990b, pp. 2-3; Fertig 1994, unpaginated; Heidel 2005, p. 3).

Discovery and Taxonomy

Boechera pusilla was first collected near South Pass in Fremont County, Wyoming, in 1981 (Dorn 1990b, p. 1). B. pusilla is a member of the Brassicaceae (mustard) family and was formerly classified as Arabis pusilla (Fertig 1994, unpaginated), which was the name used in the petition (Forest Guardians 2007, p. 23). However, studies in 2003 suggest that most North American Arabis species should be placed in the Boechera genus (Al-Shehbaz 2003, entire). This determination was based on their distinct chromosome numbers and on molecular data indicating that American and Eurasian species that were classified as Arabis have more dissimilarities between them than they do with many other widely recognized genera in the mustard family (Al-Shehbaz 2003, pp. 382-383). Although some botanists do not fully support the change (Murray and Elven 2009, unpaginated), reclassification to the Boechera genus has been widely accepted (Holmgren et al. 2005, p. 537; Flora of North America 2010b, unpaginated). For the purposes of this finding, we primarily refer to the species as Boechera pusilla, but consider Arabis pusilla to be the same species.

Boechera pusilla is genetically closely related to Boechera demissa var. languida (nodding rockcress), Boechera pendulina var. russeola (Daggett rockcress), and Boechera oxylobula (Glenwood Springs rockcress) and occurs in a similar geographic area as B. demissa var. languida and B. pendulina var. russeola (Dorn 1990b, p. 5; Heidel 2005, p. 2) . Five additional species of rockcress occur in or near B. pusilla habitat, representing a high amount of diversity within the genus (Heidel 2005, p. 2). B. pusilla requires a highly specialized habitat (discussed below under Habitat) that is newly formed, which suggests the species is relatively recently derived from a common ancestor (Dorn 1990b, p. 5). Based on morphological evidence, B. pusilla may be a hybrid of B. pendulina and B. lemmonii (Lemmon's rockcress) (Flora of North America 2010b, unpaginated). We recognize B. pusilla as a valid species and a listable entity.

Biology and Life History

Due to the short growing season (approximately 30 days) in the areas that Boechera pusilla occupies, the plant only flowers in May and June with fruits maturing several weeks later (Dorn 1990b, p. 9; Fertig 1994, unpaginated; Heidel 2005, pp. 3, 15). Fruits are only evident during the short frost-free period during the middle of summer (primarily July) and shatter thereafter (Heidel 2005, p. 15). Remnant flower stalks persist through the winter and into the next flowering season (Heidel 2005, p. 15).

Not all plants produce fruit in a particular year (Heidel 2005, pp. 15-16), which is thought to be caused by freezing conditions in spring or possibly drought (Heidel 2005, pp. 15-16). All Boechera pusilla reproduction is apparently by seed (Dorn 1990b, p. 9; Heidel 2005, p. 15), and the species is apomictic (i.e., reproduces by seed with no fertilization, resulting in offspring that are essentially clones) (Flora of North America 2010b, unpaginated). However, similar Boechera species have variation in the amount of sexual and asexual reproduction (Roy 1995, pp. 874-876), and we are unsure whether B. pusilla exhibits a mixed-mating system. We do not have information about how long the species' seeds remain viable or under what conditions they germinate. Apomictic species within the Boechera genus result from hybridization of sexual Boechera species (Flora of North America 2010b, unpaginated). Reproduction of B. pusilla is by (nonwinged) seeds that likely drop near the parent plant, with some seeds dispersed via wind or water (Dorn 1990b, p. 9). It has relatively few seeds per fruit compared to some other Boechera species (Dorn 1990b, p. 9). Dispersal vector information is unknown at this time (Heidel 2005, p. 15).

Habitat

Boechera pusilla occupies sparsely vegetated, coarse granite soil pockets in exposed granite-pegmatite outcrops, with slopes generally less than 10 degrees, at an elevation between 2,438 to 2,469 m (8,000 to 8,100 ft) (Dorn 1990b, pp. 3, 6). A pegmatite is a very coarse-grained igneous (formed from magma or lava) rock that usually occurs in dikes (sheet-like body of magma) (Heidel 2005, p. 8). The soils are sandy to loamy (mixture of clay, silt and sand), poorly developed, very shallow, and possibly subirrigated by runoff from the adjacent exposed bedrock (solid consolidated rock) (Dorn 1990b, pp. 6-8). B. pusilla is likely restricted in distribution by the limited occurrence of pegmatite in the area (Heidel 2005, p. 8). A distribution model shows potential habitat could occur in an area no greater than two townships (186.5 km²; 72 mi²) (Heidel 2005, p. 7). The dense nature of pegmatite does not allow for fertile soil, therefore restricting vegetation growth (Heidel 2005, p. 15). The specialized habitat requirements of B. pusilla have allowed the plant to persist without competition from other herbaceous plants or sagebrush-grassland species that are present in the surrounding landscape (Dorn 1990b, pp. 6, 8).

Although the surrounding vegetation is sparse (less than 10 percent cover), Boechera pusilla is associated with numerous mat-forming perennial herbs (e.g., Erigeron caespitosus (tufted fleabane)), perennial grasses (e.g., Achnatherum hymenoides (Indian ricegrass)), and shrubs (e.g., Artemesia arbuscula (dwarf sagebrush)) (Heidel 2005, p. 9). Rolling hills with a gradual sloping impediment are the predominant landscape features in the area, which is a transition zone between the montane conifer forests and the high sagebrush desert (Heidel 2005, pp. 8-9). The adjacent vegetation consists primarily of sagebrush-grassland or open Pinus flexilis (limber pine) habitat (Dorn 1990b, p. 8).

Annual precipitation in the area averages 30.5 cm (12 in.), with the majority falling in the form of winter snow (Marriott 1986, p. 9). Average minimum and maximum temperatures in this area range between −16.1 and −3.9 °C (3 and 25 °F) in January and 4.6 and 24.4 °C (42 and 76 °F) in July (Dorn 1990b, p. 6), with strong, frequent winds present year-round (Heidel 2005, p. 10). This area has a very short growing season; approximately 30 frost-free days occur between mid-June and mid-July (Marriott 1986, p. 9). Boechera pusilla may be adapted to wide fluctuations in available moisture as the soil goes through cycles of rapid drying and saturation (Dorn 1990b, p. 6).

Distribution and Abundance

The distribution of Boechera pusilla is extremely limited due to its very specific habitat requirements (Dorn 1990b, p. 8). The only known population of B. pusilla is located on lands administered by the BLM Rock Springs Field Office in the southern foothills of the Wind River Range (Fertig 2000a, p. 39; Heidel 2005, pp. ii, 6). The species' range is approximately 64.8 ha (160 ac), with occupied habitat estimates ranging from 2.4 to 6.5 ha (6 to 16 ac) (Dorn 1990b, p. 8; Heidel 2005, p. 15). Botanists have surveyed for B. pusilla systematically in other areas and discovered no additional populations, but some areas with potential habitat have not been surveyed (Marriott 1986, p. 8; Heidel 2005, p. 6).

To explain the trend of Boechera pusilla numbers, we use the estimates of total flowering plants in the entire population (i.e., total for the species) and the total flowering plants in a plot located in the largest subpopulation. These two indicators are the most consistently documented information we could find. The number of flowering plants is used, at least in part, to ensure identification of the species (Heidel 2010d, pers. comm.). In 1988, the total population estimate was 800 to 1,000 flowering individuals (Heidel 2005, p. 14). This was an increase from the 50 plants found in 1986; however, only 1 subpopulation was discovered that year (Marriott 1986, p. 15). In 1990, numbers were down to about 600 flowering plants for the entire population (Dorn 1990b, p. 8). Although the 1988 survey indicated no evidence that B. pusilla was affected by the 1988 drought (Marriott and Horning in litt. 1988, p. B2), drought impacts, such as reduced seed fecundity or germination, may not be immediately apparent (Heidel 2010c, pers. comm.; 2010d, pers. comm.). The decrease to 600 flowering plants documented in 1990 may be due to a pattern of short-term decline under drought conditions that occurred in this area between 1988 and 1990 (Heidel 2005, p. 14).

In 2003, WYNDD estimated total flowering plants for the entire population at 150 to 250 (Heidel 2005, p. 14). The mean density of flowering plants derived from the 1988 and 2003 surveys indicate that the density dropped from 1.68 down to 0.33 flowering plants per m² (0.156 down to 0.031 flowering plants per ft²) during this 15-year period (Heidel 2005, p. 14). Declines in 2003 may be attributed to severe drought conditions recorded in the Wind River Range between 2000 and 2003 (NOAA 2005 as cited in Heidel 2005, p. 14). Flowering plants for the entire population in 2010 were estimated at approximately 350 individuals (Heidel 2010d, pers. comm.).

The subpopulation plot, where the largest number of plants is found, had 671 individual flowering Boechera pusilla plants in 1988 (Heidel 2005, p. 14). This area had 87 flowering plants when it was counted again in 2003 (Heidel 2005, p. 14). In 2010, the plot had 56 flowering plants (Heidel 2010c, pers. comm.). Flowering plant numbers in the subpopulation plot has consistently declined. However, numbers of flowering plants for the entire subpopulation where the plot is located increased from between 100 and 150 in 2003 (Heidel 2005, p. 14) to 283 in 2010 (Heidel 2010c, pers. comm.). The decrease of plants in the plot but increase in the subpopulation over this period suggests the distribution of the subpopulation shifted over that period of time (Heidel 2010c, pers. comm.).

Boechera pusilla has at least eight subpopulations (Amidon 1994, in litt., unpaginated), the largest of which has been surveyed periodically as described above (Heidel 2005, p. 14; Heidel 2010c, pers. comm.). Additional subpopulations are small; in 2003, 1 subpopulation had 30 to 50 flowering plants, another had 10 to 15 flowering plants, and 5 of the subpopulations had less than 5 flowering plants each (Heidel 2005, p. 14).

Based on a limited number of surveys, the plant appears to have an overall pattern of decline documented since estimates were first provided in 1988 (Heidel 2005, p. 17; Heidel 2010c, pers. comm.; Windham 2010, pers. comm.). Boechera pusilla numbers increased in 2010 compared to 2003, but the overall trend is downward, with 2010 population numbers at 350 compared to 800 to 1000 in 1988.

Reproductive success may vary considerably from year to year depending on climate conditions, leading to wide fluctuations in populations (Dorn 1990b, p. 10). Possible evidence of these fluctuations is low levels of fruit production in 2003 that visibly increased in 2010 (Heidel 2010c, pers. comm.). However, 2010 plant numbers are low compared to those documented in 1988 and 1990.

Five Factor Evaluation for Boechera pusilla

Information pertaining to Boechera pusilla in relation to the five factors provided in section 4(a)(1) of the Act is discussed below.

Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

The following potential factors that may affect the habitat or range of Boechera pusilla are discussed in this section: (1) Recreational activities, (2) energy development, (3) nonnative invasive plants, (4) climate change, and (5) drought.

Recreational Activities

Boechera pusilla's current known range is highly restricted. All known occurrences are on BLM land, which is public land managed for multiple use (Dorn, 1990, p. 10; Heidel 2005, p. 6). Prior to the development of a Habitat Management Plan (BLM 1994, entire) and the closure of vehicle access in 1994 (59 FR 37258), B. pusilla was more readily exposed to recreation activity from ORV use associated with fishing and camping, unauthorized ORV use, horse boarding and feeding, plant collecting, mountain biking and pedestrian use. In addition, a nearby quarry, that is now inactive, may have destroyed potential habitat (Dorn 1990b, p. 11; Heidel 2005, p. 17). Previously, ORV use has been identified as a potential threat; however, conservation measures, such as the habitat management plan, have been implemented to eliminate this threat. Currently, the only access to the area occupied by B. pusilla is by foot, but due to the rocky substrate associated with the habitat, recreational use in the area primarily occurs on adjacent riparian areas, away from occupied habitat (Dana 2010a, pers. comm.). Therefore, recreational activities are not considered a threat now or in the foreseeable future.

Energy Development

The extraction of natural gas occurs in several developments in southwest Wyoming, which could be a potential threat to the habitat of Boechera pusilla (USGS 2010, p. 3). However, the area occupied by B. pusilla is incorporated into a Special Recreation Management Area (SRMA), which is closed to mineral and energy development (BLM 1997, pp. 17-18). Currently the nearest gas development occurs approximately 10.1 km (6.3 mi) from the location of B. pusilla (Kile 2010, pers. comm.) and does not appear to be a threat to the plant.

In addition, on February 23, 1998, the Secretary of the Interior issued Public Land Order No. 7312, the Withdrawal of Public Land for the Protection of Arabis Pusilla Plant Habitat. This order pursuant to Section 204 of the Federal Land Policy and Management Act of 1976, 43 U.S.C. 1714 (1994), withdrew from “settlement, sale, location, or entry under the general land laws, including the United States mining laws (30 U.S.C. Ch. 2 (1994)), but not from leasing under the mineral leasing laws” on 412.8 ha (1,020 ac) to protect Boechera pusilla habitat (63 FR 9012). This withdrawal expires in 50 years (2048) unless the Secretary determines that the withdrawal shall be extended. Therefore, we do not consider energy development to be a threat to B. pusilla now or in the foreseeable future.

Nonnative Invasive Plants

For general background information on nonnative invasive plants, please refer to the first paragraph of “Nonnative Invasive Plants” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

The habitat adjacent to the area occupied by Boechera pusilla is primarily sagebrush steppe, which is highly vulnerable to nonnative invasive species (Anderson and Inouye 2001, pp. 531-532); however, surveys conducted by WNDD in 2003 found the area generally free of nonnative invasive species (Heidel 2005, p. 10). As noted previously, the restrictive habitat occupied by B. pusilla may limit the potential for competition from other herbaceous plants (Dorn 1990b, pp. 6, 8). We have no information that nonnative invasive plants are a threat to B. pusilla. Therefore, we do not consider nonnative invasive plants to be a threat to B. pusilla now or in the foreseeable future.

Climate Change

For general background information on climate change, please refer to the first paragraphs of “Climate Change” under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range in the Five Factor Evaluation for Abronia ammophila section.

Plant species with restricted ranges may experience population declines as a result of climate change. The habitat for Boechera pusilla appears to be exposed to variation in moisture, and B. pusilla may be adapted to some variation in moisture availability (Dorn 1990b, p. 6). Climate change has the potential to affect the species' habitat, but we lack scientific information on what those changes may ultimately mean for B. pusilla. Climate change may affect the timing and amount of precipitation as well as other factors linked to habitat conditions for this species. However, at this time the available scientific information does not indicate that climate change is likely to threaten the species. Therefore, we do not consider climate change to be a threat to B. pusilla now or in the foreseeable future.

Drought

Limited evidence shows there may be some response of Boechera pusilla to drought conditions, but those effects may be delayed (Heidel 2010c, pers. comm.). As discussed above, a 1988 survey, conducted during a drought year, found increased abundance of plants from 1986 (Marriott and Horning in litt. 1988, p. B2), but surveys conducted in 1990 found reduced numbers (Dorn 1990b, p. 8) that may have been caused by continued drought conditions (Heidel 2005, p. 14). Reproductive success may vary considerably from year to year depending on climate conditions, leading to wide fluctuations in populations (Dorn 1990b, p. 10). Overall reductions in population size since 1988 may be linked to periods of drought conditions that have occurred between 1988 and 2010, but B. pusilla monitoring efforts are not sufficient during this period to understand the role of drought in population decline. Therefore, because of lack of evidence, we do not consider drought to be a threat to B. pusilla now or in the foreseeable future.

Summary of Factor A

In summary, we found that numerous management actions taken previously by the BLM alleviated several potential threats to Boechera pusilla and its habitat. These potential threats included ORV use, heavy foot traffic, and mining. The ORV use and mining are no longer permitted in the area due to the implementation of numerous regulatory mechanisms (see Factor D. Inadequacy of existing regulatory mechanisms below) in addition to the construction of an exclosure. We have no information that nonnative invasive plants are a threat to the species. Other activities in the area, such as limited foot traffic, are not considered threats. Although climate change may be a potential long-term stressor to B. pusilla, the limited information available regarding climate change impacts on B. pusilla and the species' adaptations to an already-variable climate do not suggest that climate change currently, or in the foreseeable future, will threaten this species' existence. We do not fully understand the response of B. pusilla to drought conditions, but limited evidence indicates that drought may be contributing to this species' reduced population size (see Factor E. Other Natural Or Manmade Factors Affecting Its Continued Existence discussion below). However, we do not have sufficient information to say that drought alone, or in combination with other factors, threatens the species currently or is likely to do so in the foreseeable future.

We conclude that the best scientific and commercial information available indicates that Boechera pusilla is not in danger of extinction or likely to become so within the foreseeable future because of the present or threatened destruction, modification, or curtailment of its habitat or range.

Factor B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes

Field notes from 1993 suggest that some Boechera pusilla seed had been collected and sent to the DBG; however, they do not have a record of receiving any B. pusilla seeds (Neale 2010b, pers. comm.). Some specimens collected in the 1980s were provided to the Gray Herbarium of Harvard University, the New York Botanical Garden, and the Rocky Mountain Herbarium at the University of Wyoming (Dorn 1990b, p. 5, 14). We have no other indication that any collections or utilization have been made of B. pusilla. Therefore, we find that B. pusilla is not in danger of extinction or likely to become so within the foreseeable future because of overutilization for commercial, recreational, scientific, or educational purposes.

Factor C. Disease or Predation

Disease

Boechera pusilla is not specifically known to be affected or threatened by any disease. Systemic rust disease is known to affect many Boechera species (Ladyman 2005, p. 26), but we have no information that it is found in B. pusilla. Therefore, we do not consider disease to be a threat to B. pusilla now or in the foreseeable future.

Predation—Grazing and Herbivory

Prior to conservation measures taken by the BLM, the habitat of Boechera pusilla was grazed by cattle. Prior to 1982, cattle grazing may have formed a threat, but the establishment of an ACEC that covers all known locations of B. pusilla (BLM 1997, p. 34) and the presence of an exclosure fence that encloses all of the occupied habitat (Dunder 1984, unpaginated; Marriott 1986, p. 14) have resolved this potential threat. These protections are described in additional detail under Factor D. Inadequacy of Existing Regulatory Mechanisms below. Insects, such as caterpillars, do not appear to favor B. pusilla over other vegetation (Heidel 2005, p. 10), and no known observations suggest that herbivory from wild ungulates or small mammals is a threat. Therefore, we do not consider predation to be a threat to B. pusilla now or in the foreseeable future.

Summary of Factor C

We do not have any information to suggest that disease or predation are a threat to this species. We conclude that the best scientific and commercial information available indicates that Boechera pusilla is not in danger of extinction or likely to become so within the foreseeable future because of disease or predation.

Factor D. Inadequacy of Existing Regulatory Mechanisms

The Act requires us to examine the adequacy of existing regulatory mechanisms with respect to threats that may place Boechera pusilla in danger of extinction or likely to become so in the future. Existing regulatory mechanisms that could have an effect on potential threats to B. pusilla include (1) Federal laws and regulations; (2) State laws and regulations; and (3) local land use laws, processes, and ordinances. Because the entire population of Boechera pusilla occurs on BLM lands, we focus our discussion on Federal laws. Actions adopted by local groups, States, or Federal entities that are discretionary, including conservation strategies and guidance, are not regulatory mechanisms; however, we may discuss them in relation to their effects on potential threats to the species.

Federal Laws and Regulations

Bureau of Land Management

Several regulatory mechanisms are in place to protect Boechera pusilla, some of which were mentioned under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range above. The BLM has excluded grazing from the habitat area, developed a habitat management plan for the species, designated the habitat area as an ACEC, incorporated the habitat area into a SRMA, and designated B. pusilla as a sensitive species. Additionally, the Secretary of the Interior removed essentially the entire area with occupied habitat from mineral development. The Service previously published a notice of review in 2000 removing B. pusilla as a candidate species, largely based on protections provided by these regulatory mechanisms and land management approaches.

The BLM designated the Pine Creek Special Management Area in 1978 (Heidel 2005, p. 16) and built an exclosure fence in 1982 to keep cattle out of the 35.6-ha (88-ac) area where recreational activities occur (Dunder 1984, unpaginated). Boechera pusilla occurs within this management area (Marriott 1986, p. 14). The fenced portion of the area is smaller than that of the known species range, but protects much of the occupied habitat. As described under Factor A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range above, the BLM provided a Habitat Management Plan for B. pusilla (BLM 1994, entire) and processed an emergency closure of vehicle access to 202.3 ha (500 ac) in a Habitat Management Area for the species in 1994 (59 FR 17718).

The BLM 6840 Manual requires that RMPs should address sensitive species, and that implementation “should consider all site-specific methods and procedures needed to bring species and their habitats to the condition under which management under the Bureau sensitive species policies would no longer be necessary” (BLM 2008, p. 2A1). The Federal Land Policy and Management Act of 1976 mandates Federal land managers to develop and revise land use plans. The RMPs are the basis for all actions and authorizations involving BLM-administered lands and resources (43 CFR 1601.0-5(n)). The 1997 RMP for the area that includes Boechera pusilla habitat provided designation of a Special Status Plant ACEC that closed the area to: (1) Direct surface-disturbing activities, (2) mining claims, (3) surface occupancy and surface-disturbance activities, (4) mineral material sales, and (5) use of explosives and blasting (BLM 1997, p. 34). B. pusilla habitat also fits within an SRMA designated in the RMP, which: (1) Prohibited major facilities (e.g., power lines), (2) closed the area to mineral leasing, (3) closed the ACEC to ORV use, and (4) required avoidance and extensive planning of long, linear facilities (e.g., roads) (BLM 1997, pp 17-18). All activities concerning B. pusilla in the RMP have been implemented (Glennon 2010b, pers. comm.). The next RMP revision for the area is currently underway, with an estimated completion date of 2013 (Dana 2010b, pers. comm.). Existing protections for the species will likely remain in place in the revised RMP as a no-action alternative under NEPA, but we are uncertain whether additional protections for B. pusilla will be developed.

National Environmental Policy Act

The entire known population of Boechera pusilla occurs on Federal land. All Federal agencies are required to adhere to the NEPA for projects they fund, authorize, or carry out. Please refer to the NEPA discussion under Factor D. The Inadequacy of Existing Regulatory Mechanisms in the Five Factor Evaluation for Abronia ammophila section for additional information.

Public Land Order No. 7312

On February 23, 1998, the Secretary of the Interior issued Public Land Order No. 7312 to withdraw public land from certain uses for 50 years as a measure to protect Boechera pusilla. This order withdrew 412.8 ha (1,020 ac) from settlement, sale, location of minerals, or entry under the general land laws, including mining laws; this did not eliminate the area from being leased under the mineral leasing laws (63 FR 9012). In addition to these measures, B. pusilla was listed as a BLM sensitive species in 2002 (BLM 2002, p. 9).

Summary of Factor D

Because the entire population of Boechera pusilla occurs on BLM lands, this agency has responsibility for the land management decisions that protect B. pusilla and its habitat. B. pusilla receives adequate protection from the BLM in the form of regulatory mechanisms, designations, and the construction of animal exclosures. These protections greatly limit the amount of disturbance that can occur within the plant's limited range. Although these mechanisms do not entirely exclude the area from foot traffic, they have adequately reduced this potential threat. Various regulatory mechanisms are in place to address potential threats over which the BLM has control. We expect that B. pusilla and its habitat will be generally protected from direct human disturbance.

We have no evidence of impacts to Boechera pusilla from inadequate regulatory mechanisms. We recognize that the existing regulatory mechanisms have not been able to stem the decline of the species, but we are not able to identify that regulatory mechanisms are inadequate. We are uncertain what is causing reduced population levels and consider the reduction to be an indicator that a threat is present; however, we are not able to fully describe this threat at this time (see Factor E. Other Natural Or Manmade Factors Affecting Its Continued Existence discussion below). The current small population size creates a vulnerability that may work in combination with the threat that we are not able to explain. Since the primary management tool that implements regulatory mechanisms, the RMP, goes through revisions approximately every 15 years (Dana 2010b, pers. comm.), it will be important for the BLM to ensure that the protective measures are sustained in future revisions to the Green River RMP and that measures be taken to alleviate any potential vulnerabilities created by small population size.

We conclude that the best scientific and commercial information available indicates that Boechera pusilla is not in danger of extinction or likely to become so within the foreseeable future because of inadequate regulatory mechanisms. We recognize that the existing regulatory mechanisms do not appear to have protected the species from decline; however, we are unable to conclude that regulatory mechanisms are inadequate since the cause for decline is unidentified.

Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence

Natural and manmade factors with the potential to affect Boechera pusilla include: (1) Small population size, and (2) threats not yet fully identified.

Small Population Size

For general background information on small population size, please refer to the first paragraph of “Small Population Size” under Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence in the Five Factor Evaluation for Abronia ammophila section.

In order for a population to sustain itself, there must be enough reproducing individuals and habitat to ensure its survival. Conservation biology defines this as the “minimum viable population” requirement (Grumbine 1990, pp. 127-128). This requirement may be between 500 and 5,000 individuals for other species of Boechera depending on variability among species, demographic constraints, and evolutionary history (Ladyman 2005, p. 26). Boechera pusilla occurs in relatively small numbers, with the total population size no greater than 1,000 flowering plants in the past (Heidel 2005, p. 14) and at 350 flowering plants in 2010 (Heidel 2010d, pers. comm.). Plant numbers are at levels that may not ensure this species' continued existence over the long term. As noted above, botanists who have studied B. pusilla note an overall declining trend of the species (Heidel 2005, p. 14; Heidel 2010c, pers. comm.; Windham 2010, pers. comm.). This decline has been rapid compared to declines observed in other rare species and has continued after habitat protections were put in place (Windham 2010, pers. comm.). As established in an earlier section, the number of flowering plants in the population in 2010 was approximately 350, an increase from 2003 estimates of 150 to 250. However, if a decline similar to the significant decrease between 1988 (800 to 1,000 flowering plants) and 2003 (150 to 250 flowering plants) occurs again, the species may have difficulty perpetuating itself into the future.

Boechera pusilla relies on soils formed from a certain type of granitic outcrop that is limited in extent, so the range of the species is not likely to expand beyond this area in the future. The relatively small area that B. pusilla occurs within also may predispose the species to be more sensitive to stochastic events that might occur (Menges 1990, p. 53; Boyce 1992, pp. 482-484), such as climate shift that the species is not adapted to or factors that lead to reduced reproductive success (Ladyman 2005, pp. 30-31). A single unforeseen event in a relatively small area could eliminate the species.

Boechera pusilla is apomictic, so when it uses this reproductive process, the species essentially clones itself. We are uncertain how long the species' apomictic seeds remain viable or under what conditions they germinate. This reproductive process may reduce some of the risks associated with small population size for species that only sexually reproduce. If the species reproduces only asexually, risks related to lack of genetic variability may increase, but we are uncertain if B. pusilla also reproduces sexually as do some other species of Boechera. Apomixis has been shown to reduce extinction risk if certain other variables are present, such as high levels of biomass and no soil acidity (Freville et al. 2007, p. 2666). However, information on what apomixis means for conservation of a species remains limited (Freville et al. 2007, p. 2669).

Threats Not Yet Fully Identified

In addition to the small population size of Boechera pusilla, an unknown threat or threats may be present that is causing reduced numbers of the plant. The species was removed from the candidate list in 2000 based on the regulatory protections that were in place. Based on our current understanding of the species, these regulatory protections appear appropriate and sufficient. However, the species still has small population numbers that have declined overall since the implementation of these protections. We do not understand the nature of the threat or threats, but the reduced population numbers demonstrate that some type of threat is present. We have limited data to inform our understanding of what this threat could be. The decline could be linked to drought cycles, but we do not have sufficient data to correlate numbers of B. pusilla with drought. A disease could be present in the species, but we have no information to indicate disease is reducing the number of plants.

Summary of Factor E

Boechera pusilla has a small population size that is confined to a small area because of habitat requirements. The species may be vulnerable to stochastic events due to its small population size. B. pusilla reproduces itself asexually, which may reduce some risks of a small population size, but does not fully eliminate this threat. Declines have occurred in the species, even after habitat protection measures were put in place. Although the population numbers increased from 2003 (150-250 flowering plants) to 2010 (350 flowering plants), numbers remain low, the plant appears to have an overall trend of decline, and this overall trend may continue in the foreseeable future. A viable population for the species may be 500 to 5,000 plants (Ladyman 2005, p. 26), and species numbers are below that level. We are uncertain what is causing reduced population levels and consider the reduction to be an indicator that a threat is present for the species. We are not able to fully describe this threat. Some of the decline may be attributable to drought conditions, but we do not fully understand the cause of the decline. Additionally, disease may be present but has not been documented. The small population size creates a vulnerability that may work in combination with the threat that we are not able to explain. Therefore, the species appears likely to be in danger of extinction or likely to become so within the foreseeable future because of the combination of small population size and a threat that we cannot fully identify but that is manifest by an overall declining population.

Five Factor Evaluation Summary for Boechera pusilla

Boechera pusilla has a threat that is not identified, but that is indicated by the small and declining population size. The population size may be declining from a variety of unknown causes, with drought or disease possibly contributing to the trend. The trend may have been reversed somewhat, but without improved population numbers, the species may reach a population level at which other stressors become threats. The species may already be below the minimum viable population, so other stressors may begin to present threats to the species. We are unable to determine how climate change may affect the species in the future. To the extent that we understand the species, other potential habitat-related threats have been removed through the implementation of Federal regulatory mechanisms and associated actions. Overutilization, predation, and the inadequacy of regulatory mechanisms are not viewed as threats to the species.

Finding

As required by the Act, we considered the five factors in assessing whether Boechera pusilla is threatened or endangered throughout all of its range. We examined the best scientific and commercial information available regarding the past, present, and future threats faced by B. pusilla. We reviewed the petition, information available in our files, other available published and unpublished information, and we consulted with recognized B. pusilla experts and other Federal agencies.

This status review identified threats to Boechera pusilla attributable to Factor E. The primary threat to the species is from a threat that is not fully identified, but is indicated by the species' small, declining population size. This threat to B. pusilla is not fully understood, but may be connected with drought conditions, disease, or other factors. Protective measures have been taken previously to maintain the species' habitat, but the species continues to experience declines. B. pusilla has only one population, with most of the individuals occurring in a single subpopulation. The range of the species is small due to limitations of a highly specialized habitat. Although population levels increased in 2010, the species is experiencing an overall pattern of decline that we anticipate will continue. B. pusilla numbers already may be below the minimum viable population requirement, so other vulnerabilities associated with the small population may now present threats to the species. Therefore, the species appears likely to be in danger of extinction currently, or in the foreseeable future, as result of a threat that is not fully identified, but is manifest by an ongoing declining population trend.

On the basis of the best scientific and commercial information available, we find that the petitioned action to list Boechera pusilla under the Act is warranted. We will make a determination on the status of the species as threatened or endangered when we do a proposed listing determination. However, as explained in more detail below, an immediate proposal of a regulation implementing this action is precluded by higher priority listing actions, and progress is being made to add or remove qualified species from the Lists of Endangered and Threatened Wildlife and Plants.

We reviewed the available information to determine if the existing and foreseeable threats render the species at risk of extinction now such that issuing an emergency regulation temporarily listing the species under section 4(b)(7) of the Act is warranted. We determined that issuing an emergency regulation temporarily listing the species is not warranted for this species at this time, because threats to the species would not be further controlled with a change in status. Additionally, the most recent survey information suggests that, while the population has not rebounded to previous highs, the population declines also have not continued. However, if at any time we determine that issuing an emergency regulation temporarily listing Boechera pusilla is warranted, we will initiate this action at that time.

Listing Priority Number

The Service adopted guidelines on September 21, 1983 (48 FR 43098), to establish a rational system for utilizing available resources for the highest priority species when adding species to the Lists of Endangered or Threatened Wildlife and Plants or reclassifying species listed as threatened to endangered status. These guidelines, titled “Endangered and Threatened Species Listing and Recovery Priority Guidelines” address the immediacy and magnitude of threats, and the level of taxonomic distinctiveness by assigning priority in descending order to monotypic genera (genus with one species), full species, and subspecies (or equivalently, distinct population segments of vertebrates).

As a result of our analysis of the best available scientific and commercial information, we have assigned Boechera pusilla a Listing Priority Number (LPN) of 8, based on our finding that the species faces threats that are of moderate magnitude and are imminent. These threats include a threat that is not fully identified that may work in combination with the small population. Our rationale for assigning B. pusilla an LPN of 8 is outlined below.

Under the Service's guidelines, the magnitude of threat is the first criterion we look at when establishing a listing priority. The guidance indicates that species with the highest magnitude of threat are those species facing the greatest threats to their continued existence. These species receive the highest listing priority. We consider the threats that Boechera pusilla faces to be moderate in magnitude. Although the threat, as described in Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence under Five Factor Evaluation for Boechera pusilla, is not fully understood, we know it exists as indicated by the declining population. Because we have not detected the source or nature of the threat, we consider the threat to be moderate in magnitude. The population levels have decreased significantly from the recorded high in 1988 (800 to 1,000), but they also increased between 2003 (150 to 250) and 2010 (350), so we do not consider the magnitude of the threat to be high. The threat is not fully understood, but is manifest by a declining population that may have stabilized somewhat; therefore, we consider the magnitude of the threat to be moderate.

Under our LPN guidelines, the second criterion we consider in assigning a listing priority is the immediacy of threats. This criterion is intended to ensure that the species facing actual, identifiable threats are given priority over those for which threats are only potential or that are intrinsically vulnerable but are not known to be presently facing such threats. We consider the threat to Boechera pusilla as described in Factor E. Other Natural or Manmade Factors Affecting Its Continued Existence under Five Factor Evaluation for Boechera pusilla to be imminent because, although not fully identified, we have evidence that the species is currently facing a threat indicated by reduced population size. The threat appears to be ongoing, although we are unsure of the extent and timing of its effects on B. pusilla. The threat is occurring in the only known population in the United States, and the population may already be below the minimum viable population requirement, which may allow population reductions and increases in population vulnerability to occur more quickly in the future. We expect some additional declines will occur in the future, and if declines occur at rates similar to those in the past, population levels could be precariously low. Therefore, we consider the threat to be imminent.

The third criterion in our Listing Priority Number guidance is intended to devote resources to those species representing highly distinctive or isolated gene pools as reflected by taxonomy. Boechera pusilla is a valid taxon at the species level and, therefore, receives a higher priority than subspecies, but a lower priority than species in a monotypic genus. Therefore, we assigned B. pusilla an LPN of 8.

We will continue to monitor the threats to Boechera pusilla and the species' status on an annual basis, and should the magnitude or the imminence of the threats change, we will revisit our assessment of the LPN.

While we conclude that listing Boechera pusilla is warranted, an immediate proposal to list this species is precluded by other higher priority listings, which we address in the Preclusion and Expeditious Progress section below. Because we have assigned B. pusilla an LPN of 8, work on a proposed listing determination for the species is precluded by work on higher priority listing actions with absolute statutory, court-ordered, or court-approved deadlines and final listing determinations for those species that were proposed for listing with funds from Fiscal Year (FY) 2010. This work includes all the actions listed in the tables below under Preclusion and Expeditious Progress.

Preclusion and Expeditious Progress

Preclusion is a function of the listing priority of a species in relation to the resources that are available and the cost and relative priority of competing demands for those resources. Thus, in any given FY, multiple factors dictate whether it will be possible to undertake work on a listing proposal regulation or whether promulgation of such a proposal is precluded by higher priority listing actions.

The resources available for listing actions are determined through the annual Congressional appropriations process. The appropriation for the Listing Program is available to support work involving the following listing actions: Proposed and final listing rules; 90-day and 12-month findings on petitions to add species to the Lists of Endangered and Threatened Wildlife and Plants (Lists) or to change the status of a species from threatened to endangered; annual “resubmitted” petition findings on prior warranted-but-precluded petition findings as required under section 4(b)(3)(C)(i) of the Act; critical habitat petition findings; proposed and final rules designating critical habitat; and litigation-related, administrative, and program-management functions (including preparing and allocating budgets, responding to Congressional and public inquiries, and conducting public outreach regarding listing and critical habitat).

The work involved in preparing various listing documents can be extensive and may include, but is not limited to: Gathering and assessing the best scientific and commercial data available and conducting analyses used as the basis for our decisions; writing and publishing documents; and obtaining, reviewing, and evaluating public comments and peer review comments on proposed rules and incorporating relevant information into final rules. The number of listing actions that we can undertake in a given year also is influenced by the complexity of those listing actions; that is, more complex actions generally are more costly. The median cost for preparing and publishing a 90-day finding is $39,276; for a 12-month finding, $100,690; for a proposed rule with critical habitat, $345,000; and for a final listing rule with critical habitat, the median cost is $305,000.

We cannot spend more than is appropriated for the Listing Program without violating the Anti-Deficiency Act (see 31 U.S.C. 1341(a)(1)(A)). In addition, in FY 1998 and for each FY since then, Congress has placed a statutory cap on funds which may be expended for the Listing Program, equal to the amount expressly appropriated for that purpose in that FY. This cap was designed to prevent funds appropriated for other functions under the Act (for example, recovery funds for removing species from the Lists), or for other Service programs, from being used for Listing Program actions (see House Report 105-163, 105th Congress, 1st Session, July 1, 1997).

Since FY 2002, the Service's budget has included a critical habitat subcap to ensure that some funds are available for other work in the Listing Program (“The critical habitat designation subcap will ensure that some funding is available to address other listing activities” (House Report No. 107-103, 107th Congress, 1st Session, June 19, 2001)). In FY 2002 and each year until FY 2006, the Service had to use virtually the entire critical habitat subcap to address court-mandated designations of critical habitat, and consequently none of the critical habitat subcap funds were available for other listing activities. In some FYs since 2006, we have been able to use some of the critical habitat subcap funds to fund proposed listing determinations for high-priority candidate species. In other FYs, while we were unable to use any of the critical habitat subcap funds to fund proposed listing determinations, we did use some of this money to fund the critical habitat portion of some proposed listing determinations so that the proposed listing determination and proposed critical habitat designation could be combined into one rule, thereby being more efficient in our work. In FY 2011 we anticipate that we will be able to use some of the critical habitat subcap funds to fund proposed listing determinations.

We make our determinations of preclusion on a nationwide basis to ensure that the species most in need of listing will be addressed first and also because we allocate our listing budget on a nationwide basis. Through the listing cap, the critical habitat subcap, and the amount of funds needed to address court-mandated critical habitat designations, Congress and the courts have in effect determined the amount of money available for other listing activities nationwide. Therefore, the funds in the listing cap, other than those needed to address court-mandated critical habitat for already listed species, set the limits on our determinations of preclusion and expeditious progress.

Congress identified the availability of resources as the only basis for deferring the initiation of a rulemaking that is warranted. The Conference Report accompanying Pub. L. 97-304, which established the current statutory deadlines and the warranted-but-precluded finding, states that the amendments were “not intended to allow the Secretary to delay commencing the rulemaking process for any reason other than that the existence of pending or imminent proposals to list species subject to a greater degree of threat would make allocation of resources to such a petition [that is, for a lower-ranking species] unwise.” Although that statement appeared to refer specifically to the “to the maximum extent practicable” limitation on the 90-day deadline for making a “substantial information” finding, that finding is made at the point when the Service is deciding whether or not to commence a status review that will determine the degree of threats facing the species, and therefore the analysis underlying the statement is more relevant to the use of the warranted-but-precluded finding, which is made when the Service has already determined the degree of threats facing the species and is deciding whether or not to commence a rulemaking.

In FY 2010, $10,471,000 is the amount of money that Congress appropriated for the Listing Program (that is, the portion of the Listing Program funding not related to critical habitat designations for species that are already listed). Therefore, a proposed listing is precluded if pending proposals with higher priority will require expenditure of at least $10,471,000, and expeditious progress is the amount of work that can be achieved with $10,471,000. Since court orders requiring critical habitat work will not require use of all of the funds within the critical habitat subcap, we used $1,114,417 of our critical habitat subcap funds in order to work on as many of our required petition findings and listing determinations as possible. This brings the total amount of funds we had for listing actions in FY 2010 to $11,585,417.

The $11,585,417 was used to fund work in the following categories: Compliance with court orders and court-approved settlement agreements requiring that petition findings or listing determinations be completed by a specific date; section 4 (of the Act) listing actions with absolute statutory deadlines; essential litigation-related, administrative, and listing program-management functions; and high-priority listing actions for some of our candidate species. For FY 2011, on September 29, 2010, Congress passed a continuing resolution which provides funding at the FY 2010 enacted level. Until Congress appropriates funds for FY 2011, we will fund listing work based on the FY 2010 amount. In 2009, the responsibility for listing foreign species under the Act was transferred from the Division of Scientific Authority, International Affairs Program, to the Endangered Species Program. Therefore, starting in FY 2010, we use a portion of our funding to work on the actions described above as they apply to listing actions for foreign species. This has the potential to further reduce funding available for domestic listing actions. Although there are currently no foreign species issues included in our high-priority listing actions at this time, many actions have statutory or court-approved settlement deadlines, thus increasing their priority. The budget allocations for each specific listing action are identified in the Service's FY 2011 Allocation Table (part of our administrative record).

Based on our September 21, 1983, guidance for assigning an LPN for each candidate species (48 FR 43098), we have a significant number of species with a LPN of 2. Using this guidance, we assign each candidate an LPN of 1 to 12, depending on the magnitude of threats (high or moderate to low), immediacy of threats (imminent or nonimminent), and taxonomic status of the species (in order of priority: monotypic genus (a species that is the sole member of a genus); species; or part of a species (subspecies, distinct population segment, or significant portion of the range)). The lower the listing priority number, the higher the listing priority (that is, a species with an LPN of 1 would have the highest listing priority).

Because of the large number of high-priority species, we have further ranked the candidate species with an LPN of 2 by using the following extinction-risk type criteria: International Union for the Conservation of Nature and Natural Resources (IUCN) Red list status/rank, Heritage rank (provided by NatureServe), Heritage threat rank (provided by NatureServe), and species currently with fewer than 50 individuals, or 4 or fewer populations. Those species with the highest IUCN rank (critically endangered), the highest Heritage rank (G1), the highest Heritage threat rank (substantial, imminent threats), and currently with fewer than 50 individuals, or fewer than 4 populations, originally comprised a group of approximately 40 candidate species (“Top 40”). These 40 candidate species have had the highest priority to receive funding to work on a proposed listing determination. As we work on proposed and final listing rules for those 40 candidates, we apply the ranking criteria to the next group of candidates with an LPN of 2 and 3 to determine the next set of highest priority candidate species. Finally, proposed rules for reclassification of threatened species to endangered are lower priority, since as listed species, they are already afforded the protection of the Act and implementing regulations. However, for efficiency reasons, we may choose to work on a proposed rule to reclassify a species to endangered if we can combine this with work that is subject to a court-determined deadline.

We assigned Boechera pusilla an LPN of 8. This is based on our finding that the species faces immediate and moderate magnitude threats from a threat we do not fully understand but is manifest by reduced population levels that may be below the minimum viable population requirement. Under our 1983 Guidelines, a “species” facing imminent moderate-magnitude threats is assigned an LPN of 7, 8, or 9 depending on its taxonomic status. Because B. pusilla is a species, we assigned it an LPN of 8. Therefore, work on a proposed listing determination for B. pusilla is precluded by work on higher priority candidate species (i.e., species with LPN of 7); listing actions with absolute statutory, court ordered, or court-approved deadlines; and final listing determinations for those species that were proposed for listing with funds from previous FYs. This work includes all the actions listed in the tables below under expeditious progress.

With our workload so much bigger than the amount of funds we have to accomplish it, it is important that we be as efficient as possible in our listing process. Therefore, as we work on proposed rules for the highest priority species in the next several years, we are preparing multi-species proposals when appropriate, and these may include species with lower priority if they overlap geographically or have the same threats as a species with an LPN of 2. In addition, we take into consideration the availability of staff resources when we determine which high-priority species will receive funding to minimize the amount of time and resources required to complete each listing action.

As explained above, a determination that listing is warranted but precluded also must demonstrate that expeditious progress is being made to add and remove qualified species to and from the Lists of Endangered and Threatened Wildlife and Plants. As with our “precluded” finding, the evaluation of whether progress in adding qualified species to the Lists has been expeditious is a function of the resources available for listing and the competing demands for those funds. (Although we do not discuss it in detail here, we also are making expeditious progress in removing species from the list under the Recovery program in light of the resource available for delisting, which is funded by a separate line item in the budget of the Endangered Species Program. During FY 2010, we have completed two proposed delisting rules and two final delisting rules.) Given the limited resources available for listing, we find that we made expeditious progress in FY 2010 in the Listing Program and are making expeditious progress in FY 2011. This progress included preparing and publishing the following determinations:

FY 2010 and FY 2011 Completed Listing Actions

Publication date	Title	Actions	FR pages
10/08/2009	Listing Lepidium papilliferum (Slickspot Peppergrass) as a Threatened Species Throughout Its Range	Final Listing Threatened	74 FR 52013-52064.
10/27/2009	90-day Finding on a Petition To List the American Dipper in the Black Hills of South Dakota as Threatened or Endangered	Notice of 90-day Petition Finding, Not substantial	74 FR 55177-55180.
10/28/2009	Status Review of Arctic Grayling (Thymallus arcticus) in the Upper Missouri River System	Notice of Intent to Conduct Status Review for Listing Decision	74 FR 55524-55525.
11/03/2009	Listing the British Columbia Distinct Population Segment of the Queen Charlotte Goshawk Under the Endangered Species Act: Proposed rule	Proposed Listing Threatened	74 FR 56757-56770.
11/03/2009	Listing the Salmon-Crested Cockatoo as Threatened Throughout Its Range with Special Rule	Proposed Listing Threatened	74 FR 56770-56791.
11/23/2009	Status Review of Gunnison sage-grouse (Centrocercus minimus)	Notice of Intent to Conduct Status Review for Listing Decision	74 FR 61100-61102.
12/03/2009	12-Month Finding on a Petition to List the Black-tailed Prairie Dog as Threatened or Endangered	Notice of 12-month petition finding, Not warranted	74 FR 63343-63366.
12/03/2009	90-Day Finding on a Petition to List Sprague's Pipit as Threatened or Endangered	Notice of 90-day Petition Finding, Substantial	74 FR 63337-63343.
12/15/2009	90-Day Finding on Petitions To List Nine Species of Mussels From Texas as Threatened or Endangered With Critical Habitat	Notice of 90-day Petition Finding, Substantial	74 FR 66260-66271.
12/16/2009	Partial 90-Day Finding on a Petition to List 475 Species in the Southwestern United States as Threatened or Endangered With Critical Habitat	Notice of 90-day Petition Finding, Not substantial & Substantial	74 FR 66865-66905.
12/17/2009	12-month Finding on a Petition To Change the Final Listing of the Distinct Population Segment of the Canada Lynx To Include New Mexico	Notice of 12-month petition finding, Warranted but precluded	74 FR 66937-66950.
01/05/2010	Listing Foreign Bird Species in Peru & Bolivia as Endangered Throughout Their Range	Proposed Listing Endangered	75 FR 605-649.
01/05/2010	Listing Six Foreign Birds as Endangered Throughout Their Range	Proposed Listing Endangered	75 FR 286-310.
01/05/2010	Withdrawal of Proposed Rule to List Cook's Petrel	Proposed rule, withdrawal	75 FR 310-316.
01/05/2010	Final Rule to List the Galapagos Petrel & Heinroth's Shearwater as Threatened Throughout Their Ranges	Final Listing Threatened	75 FR 235-250.
01/20/2010	Initiation of Status Review for Agave eggersiana & Solanum conocarpum	Notice of Intent to Conduct Status Review for Listing Decision	75 FR 3190-3191.
02/09/2010	12-month Finding on a Petition to List the American Pika as Threatened or Endangered	Notice of 12-month petition finding, Not warranted	75 FR 6437-6471.
02/25/2010	12-Month Finding on a Petition To List the Sonoran Desert Population of the Bald Eagle as a Threatened or Endangered Distinct Population Segment	Notice of 12-month petition finding, Not warranted	75 FR 8601-8621.
02/25/2010	Withdrawal of Proposed Rule To List the Southwestern Washington/Columbia River Distinct Population Segment of Coastal Cutthroat Trout (Oncorhynchus clarki clarki) as Threatened	Withdrawal of Proposed Rule to List	75 FR 8621-8644.
03/18/2010	90-Day Finding on a Petition to List the Berry Cave salamander as Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 13068-13071.
03/23/2010	90-Day Finding on a Petition to List the Southern Hickorynut Mussel (Obovaria jacksoniana) as Endangered or Threatened	Notice of 90-day Petition Finding, Not substantial	75 FR 13717-13720.
03/23/2010	90-Day Finding on a Petition to List the Striped Newt as Threatened	Notice of 90-day Petition Finding, Substantial	75 FR 13720-13726.
03/23/2010	12-Month Findings for Petitions to List the Greater Sage-Grouse (Centrocercus urophasianus) as Threatened or Endangered	Notice of 12-month petition finding, Warranted but precluded	75 FR 13910-14014.
03/31/2010	12-Month Finding on a Petition to List the Tucson Shovel-Nosed Snake (Chionactis occipitalis klauberi) as Threatened or Endangered with Critical Habitat	Notice of 12-month petition finding, Warranted but precluded	75 FR 16050-16065.
04/05/2010	90-Day Finding on a Petition To List Thorne's Hairstreak Butterfly as threatened or Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 17062-17070.
04/06/2010	12-month Finding on a Petition To List the Mountain Whitefish in the Big Lost River, Idaho, as Endangered or Threatened	Notice of 12-month petition finding, Not warranted	75 FR 17352-17363.
04/06/2010	90-Day Finding on a Petition to List a Stonefly (Isoperla jewetti) & a Mayfly (Fallceon eatoni) as Threatened or Endangered with Critical Habitat	Notice of 90-day Petition Finding, Not substantial	75 FR 17363-17367.
04/7/2010	12-Month Finding on a Petition to Reclassify the Delta Smelt From Threatened to Endangered Throughout Its Range	Notice of 12-month petition finding, Warranted but precluded	75 FR 17667-17680.
04/13/2010	Determination of Endangered Status for 48 Species on Kauai & Designation of Critical Habitat	Final Listing Endangered	75 FR 18959-19165.
04/15/2010	Initiation of Status Review of the North American Wolverine in the Contiguous United States	Notice of Initiation of Status Review for Listing Decision	75 FR 19591-19592.
04/15/2010	12-Month Finding on a Petition to List the Wyoming Pocket Gopher as Endangered or Threatened with Critical Habitat	Notice of 12-month petition finding, Not warranted	75 FR 19592-19607.
04/16/2010	90-Day Finding on a Petition to List a Distinct Population Segment of the Fisher in Its United States Northern Rocky Mountain Range as Endangered or Threatened with Critical Habitat	Notice of 90-day Petition Finding, Substantial	75 FR 19925-19935.
04/20/2010	Initiation of Status Review for Sacramento splittail (Pogonichthys macrolepidotus)	Notice of Initiation of Status Review for Listing Decision	75 FR 20547-20548.
04/26/2010	90-Day Finding on a Petition to List the Harlequin Butterfly as Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 21568-21571.
04/27/2010	12-Month Finding on a Petition to List Susan's Purse-making Caddisfly (Ochrotrichia susanae) as Threatened or Endangered	Notice of 12-month petition finding, Not warranted	75 FR 22012-22025.
04/27/2010	90-day Finding on a Petition to List the Mohave Ground Squirrel as Endangered with Critical Habitat	Notice of 90-day Petition Finding, Substantial	75 FR 22063-22070.
05/04/2010	90-Day Finding on a Petition to List Hermes Copper Butterfly as Threatened or Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 23654-23663.
06/01/2010	90-Day Finding on a Petition To List Castanea pumila var. ozarkensis	Notice of 90-day Petition Finding, Substantial	75 FR 30313-30318.
06/01/2010	12-month Finding on a Petition to List the White-tailed Prairie Dog as Endangered or Threatened	Notice of 12-month petition finding, Not warranted	75 FR 30338-30363.
06/09/2010	90-Day Finding on a Petition To List van Rossem's Gull-billed Tern as Endangered or Threatened	Notice of 90-day Petition Finding, Substantial	75 FR 32728-32734.
06/16/2010	90-Day Finding on Five Petitions to List Seven Species of Hawaiian Yellow-faced Bees as Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 34077-34088.
06/22/2010	12-Month Finding on a Petition to List the Least Chub as Threatened or Endangered	Notice of 12-month petition finding, Warranted but precluded	75 FR 35398-35424.
06/23/2010	90-Day Finding on a Petition to List the Honduran Emerald Hummingbird as Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 35746-35751.
06/23/2010	Listing Ipomopsis polyantha (Pagosa Skyrocket) as Endangered Throughout Its Range, & Listing Penstemon debilis (Parachute Beardtongue) & Phacelia submutica (DeBeque Phacelia) as Threatened Throughout Their Range	Proposed Listing Endangered Proposed Listing Threatened	75 FR 35721-35746.
06/24/2010	Listing the Flying Earwig Hawaiian Damselfly & Pacific Hawaiian Damselfly As Endangered Throughout Their Ranges	Final Listing Endangered	75 FR 35990-36012.
06/24/2010	Listing the Cumberland Darter, Rush Darter, Yellowcheek Darter, Chucky Madtom, & Laurel Dace as Endangered Throughout Their Ranges	Proposed Listing Endangered	75 FR 36035-36057.
06/29/2010	Listing the Mountain Plover as Threatened	Reinstatement of Proposed Listing Threatened	75 FR 37353-37358.
07/20/2010	90-Day Finding on a Petition to List Pinus albicaulis (Whitebark Pine) as Endangered or Threatened with Critical Habitat	Notice of 90-day Petition Finding, Substantial	75 FR 42033-42040.
07/20/2010	12-Month Finding on a Petition to List the Amargosa Toad as Threatened or Endangered	Notice of 12-month petition finding, Not warranted	75 FR 42040-42054.
07/20/2010	90-Day Finding on a Petition to List the Giant Palouse Earthworm (Driloleirus americanus) as Threatened or Endangered	Notice of 90-day Petition Finding, Substantial	75 FR 42059-42066.
07/27/2010	Determination on Listing the Black-Breasted Puffleg as Endangered Throughout its Range; Final Rule	Final Listing Endangered	75 FR 43844-43853.
07/27/2010	Final Rule to List the Medium Tree-Finch (Camarhynchus pauper) as Endangered Throughout Its Range	Final Listing Endangered	75 FR 43853-43864.
08/03/2010	Determination of Threatened Status for Five Penguin Species	Final Listing Threatened	75 FR 45497-45527.
08/04/2010	90-Day Finding on a Petition To List the Mexican Gray Wolf as an Endangered Subspecies With Critical Habitat	Notice of 90-day Petition Finding, Substantial	75 FR 46894-46898.
08/10/2010	90-Day Finding on a Petition to List Arctostaphylos franciscana as Endangered with Critical Habitat	Notice of 90-day Petition Finding, Substantial	75 FR 48294-48298.
08/17/2010	Listing Three Foreign Bird Species from Latin America & the Caribbean as Endangered Throughout Their Range	Final Listing Endangered	75 FR 50813-50842.
08/17/2010	90-Day Finding on a Petition to List Brian Head Mountainsnail as Endangered or Threatened with Critical Habitat	Notice of 90-day Petition Finding, Not substantial	75 FR 50739-50742.
08/24/2010	90-Day Finding on a Petition to List the Oklahoma Grass Pink Orchid as Endangered or Threatened	Notice of 90-day Petition Finding, Substantial	75 FR 51969-51974.
09/01/2010	12-Month Finding on a Petition to List the White-Sided Jackrabbit as Threatened or Endangered	Notice of 12-month petition finding, Not warranted	75 FR 53615-53629.
09/08/2010	Proposed Rule To List the Ozark Hellbender Salamander as Endangered	Proposed Listing Endangered	75 FR 54561-54579.
09/08/2010	Revised 12-Month Finding to List the Upper Missouri River Distinct Population Segment of Arctic Grayling as Endangered or Threatened	Notice of 12-month petition finding, Warranted but precluded	75 FR 54707-54753.
09/09/2010	12-Month Finding on a Petition to List the Jemez Mountains Salamander (Plethodon neomexicanus) as Endangered or Threatened with Critical Habitat	Notice of 12-month petition finding, Warranted but precluded	75 FR 54822-54845.
09/15/2010	12-Month Finding on a Petition to List Sprague's Pipit as Endangered or Threatened Throughout Its Range	Notice of 12-month petition finding, Warranted but precluded	75 FR 56028-56050.
09/22/2010	12-Month Finding on a Petition to List Agave eggersiana (no common name) as Endangered	Notice of 12-month petition finding, Warranted but precluded	75 FR 57720-57734.
09/28/2010	Determination of Endangered Status for the African Penguin	Final Listing Endangered	75 FR 59645-59656.
09/28/2010	Determination for the Gunnison Sage-grouse as a Threatened or Endangered Species	Notice of 12-month petition finding, Warranted but precluded	75 FR 59803-59863.
09/30/2010	12-Month Finding on a Petition to List the Pygmy Rabbit as Endangered or Threatened	Notice of 12-month petition finding, Not warranted	75 FR 60515-60561.
10/06/2010	Endangered Status for the Altamaha Spinymussel & Designation of Critical Habitat	Proposed Listing Endangered	75 FR 61664-61690.
10/7/2010	12-month Finding on a Petition to list the Sacramento Splittail as Endangered or Threatened	Notice of 12-month petition finding, Not warranted	75 FR 62070-62095.
10/28/2010	Endangered Status & Designation of Critical Habitat for Spikedace & Loach Minnow	Proposed Listing Endangered (uplisting)	75 FR 66481-66552.
11/2/2010	90-Day Finding on a Petition to List the Bay Springs Salamander as Endangered	Notice of 90-day Petition Finding, Not substantial	75 FR 67341-67343.
11/2/2010	Determination of Endangered Status for the Georgia Pigtoe Mussel, Interrupted Rocksnail, & Rough Hornsnail & Designation of Critical Habitat	Final Listing Endangered	75 FR 67511-67550.
11/2/2010	Listing the Rayed Bean & Snuffbox as Endangered	Proposed Listing Endangered	75 FR 67551-67583.
11/4/2010	12-Month Finding on a Petition to List Cirsium wrightii (Wright's Marsh Thistle) as Endangered or Threatened	Notice of 12-month petition finding, Warranted but precluded	75 FR 67925-67944.

Our expeditious progress also includes work on listing actions that we funded in FY 2010 and FY 2011 but have not yet been completed to date. These actions are listed below. Actions in the top section of the table are being conducted under a deadline set by a court. Actions in the middle section of the table are being conducted to meet statutory timelines, that is, timelines required under the Act. Actions in the bottom section of the table are high-priority listing actions. These actions include work primarily on species with an LPN of 2, and, as discussed above, selection of these species is partially based on available staff resources, and when appropriate, include species with a lower priority if they overlap geographically or have the same threats as the species with the high priority. Including these species together in the same proposed rule results in considerable savings in time and funding, as compared to preparing separate proposed rules for each of them in the future.

Actions Funded in FY 2010 and FY 2011 but Not Yet Completed

Species	Action
Actions Subject to Court Order/Settlement Agreement
6 Birds from Eurasia	Final listing determination.
Flat-tailed horned lizard	Final listing determination.
Mountain plover 4	Final listing determination.
6 Birds from Peru	Proposed listing determination.
Pacific walrus	12-month petition finding.
Wolverine	12-month petition finding.
Solanum conocarpum	12-month petition finding.
Desert tortoise—Sonoran population	12-month petition finding.
Thorne's Hairstreak butterfly 3	12-month petition finding.
Hermes copper butterfly 3	12-month petition finding.
Utah prairie dog (uplisting)	90-day petition finding.
Actions With Statutory Deadlines
Casey's june beetle	Final listing determination.
7 Bird species from Brazil	Final listing determination.
Southern rockhopper penguin—Campbell Plateau population	Final listing determination.
5 Bird species from Colombia and Ecuador	Final listing determination.
Queen Charlotte goshawk	Final listing determination.
5 species southeast fish (Cumberland darter, rush darter, yellowcheek darter, chucky madtom, and laurel dace) 4	Final listing determination.
Ozark hellbender 4	Final listing determination.
Altamaha spinymussel 3	Final listing determination.
3 Colorado plants (Ipomopsis polyantha (Pagosa Skyrocket), Penstemon debilis (Parachute Beardtongue), and Phacelia submutica (DeBeque Phacelia)) 4	Final listing determination.
Salmon crested cockatoo	Final listing determination.
Loggerhead sea turtle (assist National Marine Fisheries Service) 5	Final listing determination.
2 mussels (rayed bean (LPN = 2), snuffbox No LPN) 5	Final listing determination.
Mt Charleston blue 5	Proposed listing determination.
CA golden trout 4	12-month petition finding.
Black-footed albatross	12-month petition finding.
Mount Charleston blue butterfly	12-month petition finding.
Mojave fringe-toed lizard 1	12-month petition finding.
Kokanee—Lake Sammamish population 1	12-month petition finding.
Cactus ferruginous pygmy-owl 1	12-month petition finding.
Northern leopard frog	12-month petition finding.
Tehachapi slender salamander	12-month petition finding.
Coqui Llanero	12-month petition finding/Proposed listing.
Dusky tree vole	12-month petition finding.
3 MT invertebrates (mist forestfly(Lednia tumana), Oreohelix sp.3, Oreohelix sp. 31) from 206 species petition	12-month petition finding.
5 UT plants (Astragalus hamiltonii, Eriogonum soredium, Lepidium ostleri, Penstemon flowersii, Trifolium friscanum) from 206 species petition	12-month petition finding.
2 CO plants (Astragalus microcymbus, Astragalus schmolliae) from 206 species petition	12-month petition finding.
5 WY plants (Abronia ammophila, Agrostis rossiae, Astragalus proimanthus, Boechere (Arabis) pusilla, Penstemon gibbensii) from 206 species petition	12-month petition finding.
Leatherside chub (from 206 species petition)	12-month petition finding.
Frigid ambersnail (from 206 species petition) 3	12-month petition finding.
Platte River caddisfly (from 206 species petition) 5	12-month petition finding.
Gopher tortoise—eastern population	12-month petition finding.
Grand Canyon scorpion (from 475 species petition)	12-month petition finding.
Anacroneuria wipukupa (a stonefly from 475 species petition) 4	12-month petition finding.
Rattlesnake-master borer moth (from 475 species petition) 3	12-month petition finding.
3 Texas moths (Ursia furtiva, Sphingicampa blanchardi, Agapema galbina) (from 475 species petition)	12-month petition finding.
2 Texas shiners (Cyprinella sp., Cyprinella lepida) (from 475 species petition)	12-month petition finding.
3 South Arizona plants (Erigeron piscaticus, Astragalus hypoxylus, Amoreuxia gonzalezii) (from 475 species petition)	12-month petition finding.
5 Central Texas mussel species (3 from 475 species petition)	12-month petition finding.
14 parrots (foreign species)	12-month petition finding.
Berry Cave salamander 1	12-month petition finding.
Striped Newt 1	12-month petition finding.
Fisher—Northern Rocky Mountain Range 1	12-month petition finding.
Mohave Ground Squirrel 1	12-month petition finding.
Puerto Rico Harlequin Butterfly 3	12-month petition finding.
Western gull-billed tern	12-month petition finding.
Ozark chinquapin (Castanea pumila var. ozarkensis) 4	12-month petition finding.
HI yellow-faced bees	12-month petition finding.
Giant Palouse earthworm	12-month petition finding.
Whitebark pine	12-month petition finding.
OK grass pink (Calopogon oklahomensis) 1	12-month petition finding.
Ashy storm-petrel 5	12-month petition finding.
Southeastern pop snowy plover & wintering pop. of piping plover 1	90-day petition finding.
Eagle Lake trout 1	90-day petition finding.
Smooth-billed ani 1	90-day petition finding.
32 Pacific Northwest mollusks species (snails and slugs) 1	90-day petition finding.
42 snail species (Nevada & Utah)	90-day petition finding.
Red knot roselaari subspecies	90-day petition finding.
Peary caribou	90-day petition finding.
Plains bison	90-day petition finding.
Spring Mountains checkerspot butterfly	90-day petition finding.
Spring pygmy sunfish	90-day petition finding.
Bay skipper	90-day petition finding.
Unsilvered fritillary	90-day petition finding.
Texas kangaroo rat	90-day petition finding.
Spot-tailed earless lizard	90-day petition finding.
Eastern small-footed bat	90-day petition finding.
Northern long-eared bat	90-day petition finding.
Prairie chub	90-day petition finding.
10 species of Great Basin butterfly	90-day petition finding.
6 sand dune (scarab) beetles	90-day petition finding.
Golden-winged warbler 4	90-day petition finding.
Sand-verbena moth	90-day petition finding.
404 Southeast species	90-day petition finding.
Franklin's bumble bee 4	90-day petition finding.
2 Idaho snowflies (straight snowfly & Idaho snowfly) 4	90-day petition finding.
American eel 4	90-day petition finding.
Gila monster (Utah population) 4	90-day petition finding.
Arapahoe snowfly 4	90-day petition finding.
Leona's little blue 4	90-day petition finding.
Aztec gilia 5	90-day petition finding.
White-tailed ptarmigan 5	90-day petition finding.
San Bernardino flying squirrel 5	90-day petition finding.
Bicknell's thrush 5	90-day petition finding.
Sonoran talussnail 5	90-day petition finding.
2 AZ Sky Island plants (Graptopetalum bartrami & Pectis imberbis) 5	90-day petition finding.
I'iwi 5	90-day petition finding.
High-Priority Listing Actions
19 Oahu candidate species 2 (16 plants, 3 damselflies) (15 with LPN = 2, 3 with LPN = 3, 1 with LPN =9)	Proposed listing.
19 Maui-Nui candidate species 2 (16 plants, 3 tree snails) (14 with LPN = 2, 2 with LPN = 3, 3 with LPN = 8)	Proposed listing.
Dune sagebrush lizard (formerly Sand dune lizard) 4 (LPN = 2)	Proposed listing.
2 Arizona springsnails 2 (Pyrgulopsis bernadina (LPN = 2), Pyrgulopsis trivialis (LPN = 2))	Proposed listing.
New Mexico springsnail 2 (Pyrgulopsis chupaderae (LPN = 2)	Proposed listing.
2 mussels 2 (sheepnose (LPN = 2), spectaclecase (LPN = 4),)	Proposed listing.
8 Gulf Coast mussels (southern kidneyshell (LPN = 2), round ebonyshell (LPN = 2), Alabama pearlshell (LPN = 2), southern sandshell (LPN = 5), fuzzy pigtoe (LPN = 5), Choctaw bean (LPN = 5), narrow pigtoe (LPN = 5), and tapered pigtoe (LPN = 11)) 4	Proposed listing.
Umtanum buckwheat (LPN = 2) 4	Proposed listing.
Grotto sculpin (LPN = 2) 4	Proposed listing.
2 Arkansas mussels (Neosho mucket (LPN =2) & Rabbitsfoot (LPN = 9)) 4	Proposed listing.
Diamond darter (LPN = 2) 4	Proposed listing.
Gunnison sage-grouse (LPN =2) 4	Proposed listing.
Miami blue (LPN = 3) 3	Proposed listing.
4 Texas salamanders (Austin blind salamander (LPN = 2), Salado salamander (LPN = 2), Georgetown salamander (LPN = 8), Jollyville Plateau (LPN = 8)) 3	Proposed listing.
5 SW aquatics (Gonzales Spring Snail (LPN = 2), Diamond Y springsnail (LPN =2), Phantom springsnail (LPN = 2), Phantom Cave snail (LPN = 2), Diminutive amphipod (LPN = 2)) 3	Proposed listing.
2 Texas plants (Texas golden gladecress (Leavenworthia texana) (LPN = 2), Neches River rose-mallow (Hibiscus dasycalyx) (LPN = 2)) 3	Proposed listing.
FL bonneted bat (LPN =2) 3	Proposed listing.
Kittlitz's murrelet (LPN = 2) 5	Proposed listing.
Umtanum buckwheat (LPN = 2) 3	Proposed listing.
21 Big Island (HI) species 5 (includes 8 candidate species—5 plants & 3 animals; 4 with LPN = 2, 1 with LPN = 3, 1 with LPN = 4, 2 with LPN = 8)	Proposed listing.
Oregon spotted frog (LPN = 2) 5	Proposed listing.
2 TN River mussels (fluted kidneyshell (LPN = 2), slabside pearlymussel (LPN = 2) 5	Proposed listing.
Jemez Mountain salamander (LPN = 2) 5	Proposed listing.
1 Funds for listing actions for these species were provided in previous FYs.
2 Although funds for these high-priority listing actions were provided in FY 2008 or 2009, due to the complexity of these actions and competing priorities, these actions are still being developed.
3 Partially funded with FY 2010 funds and FY 2011 funds.
4 Funded with FY 2010 funds.
5 Funded with FY 2011 funds.

We have endeavored to make our listing actions as efficient and timely as possible, given the requirements of the relevant law and regulations, and constraints relating to workload and personnel. We are continually considering ways to streamline processes or achieve economies of scale, such as by batching related actions together. Given our limited budget for implementing section 4 of the Act, these actions described above collectively constitute expeditious progress.

Boechera pusilla will be added to the list of candidate species upon publication of this 12-month finding. We will continue to evaluate this species as new information becomes available. Continuing review will determine if a change in status is warranted, including the need to make prompt use of emergency listing procedures.

We intend that any proposed listing determination for Boechera pusilla will be as accurate as possible. Therefore, we will continue to accept additional information and comments from all concerned governmental agencies, the scientific community, industry, or any other interested party concerning this finding.

References Cited

A complete list of references cited is available on the Internet at http://www.regulations.gov and upon request from the Wyoming Ecological Services Field Office (see ADDRESSES section).

Author(s)

The primary authors of this notice are the staff members of the Wyoming Ecological Services Field Office.

Authority: The authority for this section is section 4 of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

Dated: May 16, 2011.

Rowan W. Gould,

Acting Director, Fish and Wildlife Service.