thefederalregister.com

Daily Rules, Proposed Rules, and Notices of the Federal Government

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2012-0069; 4500030114]

RIN 1018-AY52

Endangered and Threatened Wildlife and Plants; Proposed Listing of the Mount Charleston Blue Butterfly as Endangered and Proposed Listing of Five Blue Butterflies as Threatened Due to Similarity of Appearance

AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
SUMMARY: We, the U.S. Fish and Wildlife Service, propose to list the Mount Charleston blue butterfly (Plebejus shasta charlestonensis) as an endangered species under the Endangered Species Act of 1973, as amended (Act). We also propose to list the lupine blue butterfly (Plebejus lupini texanus), Reakirt's blue butterfly (Echinargus isola), Spring Mountains icarioides blue butterfly (Plebejus icarioides austinorum), and the two Spring Mountains dark blue butterflies (Euphilotes ancilla crypticaandE. a. purpura) as threatened due to similarity of appearance to the Mount Charleston blue, with a special rule pursuant to section 4(d) of the Act. We solicit additional data, information, and comments that may assist us in making a final decision on this proposed action. In addition, we propose to make nonsubstantive, administrative changes to a previously published listing and special rule regarding five other butterflies to correct some inadvertent errors and to make these two special rules more consistent.
DATES: We will accept comments received or postmarked on or before November 26, 2012. Comments submitted electronically using the Federal eRulemaking Portal (seeADDRESSESsection, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in theADDRESSESsection by November 13, 2012.
ADDRESSES: (1)Electronically:Go to the Federal eRulemaking Portal:http://www.regulations.gov. In the Search box, enter Docket No. FWS-R8-ES-2012-0069, which is the docket number for this rulemaking. You may submit a comment by clicking on "Comment Now!"

(2)By hard copy:Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R8-ES-2012-0069, Division of Policy and Directives Management, U.S. Fish and Wildlife Service, 4401 N. Fairfax Drive, MS 2042-PDM, Arlington, VA 22203.

We request that you send comments only by the methods described above. We will post all comments onhttp://www.regulations.gov. This generally means that we will post any personal information you provide us (see the Public Comments section below for more information).

FOR FURTHER INFORMATION CONTACT: Edward D. Koch, Field Supervisor, U.S. Fish and Wildlife Service, Nevada Fish and Wildlife Office, 1340 Financial Blvd., Suite 234, Reno, Nevada 89502, by telephone 775-861-6300 or by facsimile 775-861-6301. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION: Executive Summary

This document consists of: (1) A proposed rule to list the Mount (Mt.) Charleston blue butterfly (Plebejus shasta charlestonensis) (formerly in genusIcaricia) as an endangered species and a proposed rule to list the lupine blue butterfly (Plebejus lupini texanus), Reakirt's blue butterfly (Echinargus isola), Spring Mountains icarioides blue butterfly (Plebejus icarioides austinorum), and the two Spring Mountains dark blue butterflies (Euphilotes ancilla crypticaandE. a. purpura) as threatened due to similarity of appearance to the Mt. Charleston blue butterfly; (2) a prudency determination regarding critical habitat designation for the Mt. Charleston blue butterfly; and (3) nonsubstantive, administrative corrections to a previously published listing of the Miami blue butterfly (Cyclargus thomasi bethunebakeri) and special rule regarding the cassius blue butterfly (Leptotes cassius theonus), ceraunus blue butterfly (Hemiargus ceraunus antibubastus), and nickerbean blue butterfly (Cyclargus ammon).

Why we need to publish a rule.Under the Endangered Species Act (Act), a species may warrant protection through listing if it is an endangered or threatened species throughout all or a significant portion of its range. If a species is determined to be an endangered or threatened species throughout all or a significant portion of its range, we are required to promptly publish a proposal in theFederal Registerand make a determination on our proposal within one year. Critical habitat shall be designated, to the maximum extent prudent and determinable, for any species determined to be an endangered or threatened species under the Act. Listing a species as an endangered or threatened species and designations and revisions of critical habitat can only be completed by issuing a rule.

This rule proposes endangered status for the Mt. Charleston blue butterfly and proposes threatened status for the lupine blue butterfly, Reakirt's blue butterfly, Spring Mountains icarioides blue butterfly, and two Spring Mountains dark blue butterflies based on similarity of appearance to the Mt. Charleston blue butterfly. This rule also finds that designation of critical habitat for the Mt. Charleston blue butterfly is not prudent at this time.

The basis for our action.Under the Act, we can determine that a species is an endangered or threatened species based on any of 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. We have determined that the Mt. Charleston blue butterfly is threatened by:

• Habitat loss and degradation due to fire suppression and succession, implementation of recreation development projects and fuels reduction projects, and nonnative plant species (Factor A);

• Collection (Factor B);

• Inadequate regulatory mechanisms (Factor D); and

• Drought and extreme precipitation events, which are predicted to increase as a result of climate change (Factor E).

We have additionally determined that five species of blue butterflies warrant listing based on similarity of appearance to the Mt. Charleston blue butterfly:

• Lupine blue butterfly;

• Reakirt's blue butterfly;

• Spring Mountains icarioides blue butterfly; and

• Two Spring Mountains dark blue butterflies.

Further, we have determined that it is not prudent to designate critical habitat for the Mt. Charleston blue butterfly because the benefits are clearly outweighed by the expected increase in threats associated with a critical habitat designation:

• Publication of maps and descriptions of specific critical habitatareas will pinpoint populations more precisely than does the rule;

• Publishing the exact locations of the butterfly's habitat will further facilitate unauthorized collection and trade. Its rarity makes the Mt. Charleston blue butterfly extremely attractive to collectors; and

• Purposeful or inadvertent activities have already damaged some habitat. Many locations are difficult for law enforcement personnel to regularly access and patrol.

We will seek peer review.We are seeking comments from knowledgeable individuals with scientific expertise to review our analysis of the best available science and application of that science and to provide any additional scientific information to improve this proposed rule. Because we will consider all comments and information received during the comment period, our final determinations may differ from this proposal.

This document consists of: (1) A proposed rule to list the Mount (Mt.) Charleston blue butterfly (Plebejus shasta charlestonensis) (formerly in genusIcaricia) as an endangered species and a proposed rule to list the lupine blue butterfly (Plebejus lupini texanus), Reakirt's blue butterfly (Echinargus isola), Spring Mountains icarioides blue butterfly (Plebejus icarioides austinorum), and the two Spring Mountains dark blue butterflies (Euphilotes ancilla crypticaandE. a. purpura) as threatened due to similarity of appearance to the Mt. Charleston blue butterfly; and (2) a prudency determination regarding critical habitat designation for the Mt. Charleston blue butterfly.

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:

(1) The species' biology, range, and population trends, including:

(a) Habitat requirements for feeding, breeding, and sheltering;

(b) Genetics and taxonomy;

(c) Historical and current range including distribution patterns;

(d) Historical and current population levels, and current and projected trends; and

(e) Past and ongoing conservation measures for the species, its habitat or both.

(2) The factors that are the basis for making a listing determination for a species under section 4(a) of the Act (16 U.S.C. 1531et seq.), which are:

(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.

(3) Biological, commercial and noncommercial trade or collection, or other relevant data concerning any threats (or lack thereof) to this species and regulations that may be addressing those threats.

(4) Additional information concerning the historical and current status, range, distribution, and population size of this species, including the locations of any additional populations of this species.

(5) Any information on the biological or ecological requirements of the species, and ongoing conservation measures for the species and its habitat.

(6) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531et seq.), including whether there are threats to the species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threats outweighs the benefit of designation such that the designation of critical habitat is not prudent.

(7) Specific information on:

(a) The amount and distribution of Mt. Charleston blue butterfly and its habitat;

(b) What may constitute “physical or biological features essential to the conservation of the species,” within the geographical range currently occupied by the species;

(c) Where these features are currently found;

(d) Whether any of these features may require special management considerations or protection;

(e) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of the species, should be included in the designation and why; and

(f) What areas not occupied at the time of listing are essential for the conservation of the species and why.

(8) Land use designations and current or planned activities in the areas occupied by the species or potential habitat and their possible impacts to the Mt. Charleston blue butterfly.

(9) Information on the projected and reasonably likely impacts of climate change on the Mt. Charleston blue butterfly or its habitat.

(10) Threats to the Mt. Charleston blue butterfly from collection of or commercial trade involving the lupine blue butterfly (Plebejus lupini texanus), Reakirt's blue butterfly (Echinargus isola), Spring Mountains icarioides blue butterfly (Plebejus icarioides austinorum), and the two Spring Mountains dark blue butterflies (Euphilotes ancilla crypticaandE. a. purpura), due to the Mt. Charleston blue's similarity in appearance to these species.

(11) Effects of and necessity of establishing the proposed 4(d) special rule to establish prohibitions on collection of, or commercial trade involving, the lupine blue butterfly, Reakirt's blue butterfly, Spring Mountains icarioides blue butterfly, and two Spring Mountains dark blue butterflies.

(12) Any foreseeable economic, national security, or other relevant impacts that may result from designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas from the proposed designation that are subject to these impacts.

(13) Whether our approach to designating critical habitat could be improved or modified in any way to provide for greater public participation and understanding, or to assist us in accommodating public concerns and comments.

(14) The likelihood of adverse social reactions to the designation of critical habitat and how the consequences of such reactions, if likely to occur, would relate to the conservation and regulatory benefits of the proposed critical habitat designation.

Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.

Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is a threatened or endangered species must be made “solely on thebasis of the best scientific and commercial data available.”

You may submit your comments and materials concerning this proposed rule by one of the methods listed in theADDRESSESsection. We request that you send comments only by the methods described in theADDRESSESsection.

If you submit information viahttp://www.regulations.gov,your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions onhttp://www.regulations.gov.Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection onhttp://www.regulations.gov,or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Nevada Fish and Wildlife Office (seeFOR FURTHER INFORMATION CONTACT).

Previous Federal Actions

In 1991 and 1994, the U.S. Fish and Wildlife Service (Service) included the Mt. Charleston blue butterfly in a compilation of taxa for review and potential addition to the Lists of Endangered and Threatened Wildlife and Plants (56 FR 58804, November 21, 1991; 59 FR 58982, November 15, 1994). The Mt. Charleston blue butterfly was formerly referred to as the Spring Mountains blue (butterfly) (56 FR 58804, November 21, 1991; 59 FR 58982, November 15, 1994), but this common name is no longer used to avoid confusion with other butterflies having similar common names. In both years, the Mt. Charleston blue butterfly was assigned to “Category 2,” meaning that a proposal to list was potentially appropriate, but adequate data on biological threats or vulnerabilities were not currently available. The trend for Mt. Charleston blue butterfly was described as “declining” in 1991 and 1994 (56 FR 58804; 59 FR 58982). These notices stressed that Category 2 species were not proposed for listing by the notice, nor were there any plans to list those Category 2 species unless supporting information became available.

In the February 28, 1996, Candidate Notice of Review (61 FR 7595), we adopted a single category of candidate defined as “Those species for which the Service has on file sufficient information on biological vulnerability and threat(s) to support issuance of a proposed rule to list but issuance of the proposed rule is precluded.” In previous Candidate Notices of Review, species and subspecies matching this 1996 definition were known as Category 1 candidates for listing. Thus, the Service no longer considered Category 2 species and subspecies as candidates and did not include them in the 1996 or any subsequent Candidate Notices of Review. The decision to stop considering Category 2 species and subspecies as candidates was designed to reduce confusion about the status of these species and subspecies and to clarify that we no longer regarded these species and subspecies as candidates for listing.

On October 20, 2005, we received a petition dated October 20, 2005, from The Urban Wildlands Group, Inc., requesting that we emergency list the Mt. Charleston blue butterfly as an endangered or threatened species. In a letter to the petitioner dated April 20, 2006, we stated that our initial review did not indicate that an emergency situation existed, but that if conditions changed, an emergency rule could be developed. On May 30, 2007, we published a 90-day petition finding (72 FR 29933) in which we concluded that the petition provided substantial information indicating that listing of the Mt. Charleston blue butterfly may be warranted, and we initiated a status review. On April 26, 2010, CBD amended its complaint inCenter for Biological Diversityv.Salazar, U.S. Fish and Wildlife Service,Case No.: 1:10-cv-230-PLF (D.D.C.), adding an allegation that the Service failed to issue its 12-month petition finding on the Mount Charleston blue butterfly within the mandatory statutory timeframe. On March 8, 2011, we published a 12-month finding (76 FR 12667) in which we concluded that listing the Mt. Charleston blue butterfly was warranted, but precluded by higher priority listing actions. On October 26, 2011, we listed the Mt. Charleston blue butterfly as a new candidate in the Candidate Notice of Review (76 FR 66370).

Endangered Species Status for Mt. Charleston Blue Butterfly Background

It is our intent to discuss below only those topics directly relevant to the listing of the Mt. Charleston blue butterfly as an endangered species in this section of the proposed rule.

Taxonomy and Subspecies Description

The Mt. Charleston blue butterfly is a distinct subspecies of the wider ranging Shasta blue butterfly (Plebejus shasta), which is a member of the Lycaenidae family. Pelham (2008, pp. 25-26) recognized seven subspecies of Shasta blue:P. s. shasta, P. s. calchas, P. s. pallidissima, P. s. minnehaha, P. s. charlestonensis, P. s. pitkinensis,andP. s. platazulin “A catalogue of the butterflies of the United States and Canada with a complete bibliography of the descriptive and systematic literature” published in volume 40 of the Journal of Research on the Lepidoptera (2008, pp. 379-380). The Mt. Charleston blue butterfly is known only from the high elevations of the Spring Mountains, located approximately 25 miles (mi) (40 kilometers (km)) west of Las Vegas in Clark County, Nevada (Austin 1980, p. 20; Scott 1986, p. 410). The first mention of the Mt. Charleston blue butterfly as a unique taxon was in 1928 by Garth (p. 93), who recognized it as distinct from the species Shasta blue (Austin 1980, p. 20). Howe (in 1975, Plate 59) described specimens from the Spring Mountains as theP. s. shastaformcomstocki.However, in 1976, Ferris (p. 14) placed the Mt. Charleston blue butterfly with the wider ranging Minnehaha blue subspecies. Finally, Austin asserted that Ferris had not included populations from the Sierra Nevada in his study, and in light of the geographic isolation and distinctiveness of the Shasta blue population in the Spring Mountains and the presence of at least three other well-defined races (subspecies) of butterflies endemic to the area, it was appropriate to name this population as the subspecies Mt. Charleston blue butterfly (P. s. charlestonensis) (Austin 1980, p. 20).

Our use of the genus namePlebejus,rather than the synonymIcaricia,reflects recent treatments of butterfly taxonomy (Opler and Warren 2003, p. 30; Pelham 2008, p. 265). The Integrated Taxonomic Information System (ITIS) recognizes the Mt. Charleston blue butterfly as a valid subspecies based on Austin (1980) (Retrieved April 2, 2012, from the Integrated Taxonomic Information System on-line database,http://www.itis.gov). The ITIS is hosted by the United States Geological Survey (USGS) Center for Biological Informatics (CBI) and is the result of a partnership of Federal agencies formed to satisfy their mutual needs for scientifically credible taxonomic information.

As a subspecies, the Mt. Charleston blue butterfly is similar to other Shasta blue butterflies, with a wingspan of 0.75 to 1 inch (in) (19 to 26 millimeters (mm)) (Opler 1999, p. 251). Males and females of Mt. Charleston blue are dimorphic (occurring in two distinct forms). The upperside of males is dark to dull iridescent blue, and females are brown with a blue overlay. The species has a discal black spot on the forewing and a row of submarginal black spots on the hindwing. The underside is gray, with a pattern of black spots, brown blotches, and pale wing veins to give it a mottled appearance. The underside of the hindwing has an inconspicuous band of submarginal metallic spots (Opler 1999, p. 251). Based on morphology, the Mt. Charleston blue butterfly is most closely related to the Great Basin populations of Minnehaha blue butterfly (Austin 1980, p. 23), and it can be distinguished from other Shasta blue butterfly subspecies by the presence of sharper and blacker postmedian spots on the underside of the hindwing (Scott 1986, p. 410).

The Mt. Charleston blue butterfly is similar in appearance to five other sympatric (occupying the same or overlapping geographic areas without interbreeding) butterflies that occur roughly in the same habitats: lupine blue butterfly (Plebejus lupini texanus), Reakirt's blue butterfly (Echinargus isola), Spring Mountains icarioides blue butterfly (Plebejus icarioides austinorum), and the two Spring Mountains dark blue butterflies (Euphilotes ancilla crypticaandE. a. purpura). The lupine blue butterfly (also commonly referred to as the Acmon blue, Texas blue, or Southwestern blue butterfly) is the most similar to the Mt. Charleston blue butterfly (Boyd and Austin 1999, p. 44). The Mt. Charleston blue butterfly is distinguished from the lupine blue butterfly by a less broad and distinct orange band on the hindwing (Boyd and Austin, p. 44), and the postmedian spots on the underside of the hindwing are brown rather than black (Scott 1986, p. 410). The Reakirt's blue butterfly is similar in size or slightly smaller than the Mt. Charleston blue butterfly and is identified by black underside hindwing spots at the hind corner and large round black underside forewing spots (Scott 1986, p. 413; Opler 1999, pp. 230, 251). The Spring Mountains icarioides blue butterfly is larger than the Mt. Charleston blue butterfly and usually lacks the upperside forewing dash (Scott 1986, p. 409). In addition the underside hindwing postmedian spots of the Spring Mountains icarioides blue butterfly are typically ringed with white (Scott 1986, p. 409). The two Spring Mountains dark blue butterflies and the Spring Mountains icarioides blue butterfly lack the metallic marginal spots on the underside hindwing that is present on the Mt. Charleston blue butterfly (Scott 1986, p. 403; Brock and Kaufmann 2003, pp. 134, 136, 140). The two Spring Mountains dark blue butterflies have a more prominent orange band on the hindwing and do not have black dashes in the middle of the upperside forewing and hindwing as the Mt. Charleston blue butterfly does (Brock and Kaufmann 2003, pp. 136, 140; Scott 1986, pp. 403, 410).

Distribution

Based on current and historical occurrences or locations (Austin 1980, pp. 20-24; Weisset al.1997, Map 3.1; Boyd and Murphy 2008, p. 4, Pinyon 2011, Figure 9-11; Thompsonet al.2012, p. 99), the geographic range of the Mt. Charleston blue butterfly is in the upper elevations of the Spring Mountains, centered on lands managed by the U.S. Forest Service (Forest Service) in the Spring Mountains National Recreation Area of the Humboldt-Toiyabe National Forest within Upper Kyle and Lee Canyons, Clark County, Nevada. The majority of the occurrences or locations are along the upper ridges in the Mt. Charleston Wilderness and in Upper Lee Canyon area, while a few are in Upper Kyle Canyon. Table 1 lists the various locations of the Mt. Charleston blue butterfly that constitute the subspecies' current and historical range. Estimates of population size for Mt. Charleston blue butterfly are not available, so the occurrence data summarized in Table 1 represent the best scientific information on distribution of Mt. Charleston blue butterfly and how that distribution has changed over time.

Table 1—Locations or Occurrences of the Mt. Charleston Blue Butterfly Since 1928, and the Status of the Butterfly at the Locations [Survey efforts are variable through time] Location name First/last time observed Most recent
  • survey year(s)
  • (even if not
  • observed)
  • Status Primary references
    1. South Loop Trail, Upper Kyle Canyon 1928/2011 2007, 2008, 2010, 2011 Known occupied; adults consistently observed Weisset al.1997; Kingsley 2007; Boyd 2006; Datasmiths 2007; SWCA 2008; Pinyon 2011; Thompsonet al.2012. 2. Las Vegas Ski and Snowboard Resort (LVSSR), Upper Lee Canyon 1963/2010 2007, 2008, 2010, 2011 Known occupied; adults consistently observed Weisset al.1994; Weisset al.1997; Boyd and Austin 2002; Boyd 2006; Newfields 2006; Datasmiths 2007; Boyd and Murphy 2008;Thompsonet al.2012. 3. Foxtail, Upper Lee Canyon 1995/1998 2006, 2007, 2008 Presumed occupied; adults intermittently observed Boyd and Austin 1999; Boyd 2006; Datasmiths 2007; Boyd and Murphy 2008. 4. Youth Camp, Upper Lee Canyon 1995/1995 2006, 2007, 2008 Presumed occupied; adults intermittently observed Weisset al.1997; Boyd 2006; Datasmiths 2007; Boyd and Murphy 2008. 5. Gary Abbott, Upper Lee Canyon 1995/1995 2006, 2007, 2008 Presumed occupied; adults intermittently observed Weisset al.1997; Boyd 2006; Datasmiths 2007; Boyd and Murphy 2008. 6. Lower LVSSR Parking, Upper Lee Canyon 1995/2002 2007, 2008 Presumed occupied; adults intermittently observed Weisset al.1997; Boyd 2006; Datasmiths 2007; Boyd and Murphy 2008. 7. Mummy Spring, Upper Kyle Canyon 1995/1995 2006 Presumed occupied; adults intermittently observed Weisset al.1997; Boyd 2006. 8. Lee Meadows, Upper Lee Canyon 1965/1995 2006, 2007, 2008 Presumed occupied; adults intermittently observed Weisset al.1997; Boyd 2006; Datasmiths 2007; Boyd and Murphy 2008. 9. Bristlecone Trail 1990/2011 2007, 2011 Presumed occupied Weisset al.1995; Weisset al.1997; Kingsley 2007; Thompsonet al.2012. 10. Bonanza Trail 1995/1995 2006, 2007 Presumed occupied Weisset al.1997; Boyd 2006; Kingsley 2007. 11. Upper Lee Canyon holotype 1963/1976 2006, 2007 Presumed extirpated Weisset al.1997; Boyd 2006; Datasmiths 2007. 12. Cathedral Rock, Kyle Canyon 1972/1972 2007 Presumed extirpated Weisset al.1997; Datasmiths 2007. 13. Upper Kyle Canyon Ski Area 1965/1972 1995 Presumed extirpated Weisset al.1997. 14. Old Town, Kyle Canyon 1970s 1995 Presumed extirpated The Urban Wildlands Group, Inc. 2005. 15. Deer Creek, Kyle Canyon 1950 unknown Presumed extirpated Howe 1975. 16. Willow Creek 1928 unknown Presumed extirpated Weisset al.1997; Thompson and Garrett 2010.

    We presume that the Mt. Charleston blue butterfly is extirpated from a location when it has not been recorded at that location through formal surveys or informal observation for more than 20 years. We selected a 20-year time period because it would likely allow for local extirpation and recolonization events (metapopulation dynamics) to occur and would be enough time for succession or other vegetation shifts to render the habitat unsuitable (see discussion in Biology and Habitat sections below). Using this criterion, the Mt. Charleston blue butterfly is considered to be “presumed extirpated” from 6 of the 16 known locations (Locations 11-16 in Table 1) (Service 2006b, pp. 8-9). Of the remaining 10 locations, 8 locations or occurrences are “presumed occupied” by the subspecies (Locations 3-10 in Table 1) and the first 2 locations are “known occupied” (Locations 1-2 in Table 1) (Service 2006b, pp. 7-8). We note that the probability of detection of Mt. Charleston blue butterflies at a particular location in a given year is affected by factors other than the butterfly's abundance, such as survey effort and weather, both of which are highly variable from year to year.

    The presumed occupied category is defined as a location within the current known range of the subspecies where adults have been intermittently observed and there is a potential for diapausing (a period of suspended growth or development similar to hibernation) larvae to be present. The butterfly likely exhibits metapopulation dynamics at these locations. In this situation, the subspecies is subject to local extirpation, with new individuals emigrating from nearby “known occupied” habitat, typically during years when environmental conditions are more favorable to emergence from diapause and the successful reproduction of individuals (see discussion inHabitatsection below). At some of these presumed occupied locations (Locations 4, 5, 7, 8, and 10 in Table 1), the Mt. Charleston blue butterfly has not been recorded through formal surveys or informal observation since 1995 by Weisset al.(1997, pp. 1-87). Of the presumed occupied locations, 3, 6, and 9 have had the most recent observations (observed in 1998, 2002, and 2011, respectively) (Table 1). Currently, we consider the occurrence at Mummy Spring as presumed occupied because it has been intermittently observed; however, this location is not near known occupied habitat and may be extirpated.

    We consider the remaining two Mt. Charleston blue butterfly locations or occurrences to be “known occupied” (Locations 1 and 2 in Table 1). Known occupied locations have had successive observations during multiple years of surveys and occur in high-quality habitat. The South Loop Trail location in Upper Kyle Canyon (Location 1 in Table 1) is considered known occupied because: (1) The butterfly was observed on the site in 1995, 2002, 2007, 2010, and 2011 (Service 2007, pp. 1-2; Kingsley 2007, p. 5; Pinyon 2011, pp. 17-19; Thompsonet al.2012, p. 99); (2) the high quality of the habitat is in accordance with host plant densities of 10 plants per square meter as described in Weisset al.(1997, p. 31) (Kingsley 2007, pp. 5 and 10; Thompsonet al.2012, p. 99); and (3) in combination with the observations and high-quality habitat, the habitat is in an area of relatively large size (SWCA 2008, pp. 2 and 5; Pinyon 2011, p. Figure 8). The South Loop Trail area is the most important remaining population area for the Mt. Charleston blue butterfly (Boyd and Murphy 2008, p. 21). The South Loop Trail runs along the ridgeline between Griffith Peak and Charleston Peak and is located within the Mt. Charleston Wilderness. This area was mapped using a global positioning system unit and included the larval host plant,Astragalus calycosusvar.calycosus(Torrey's milkvetch), as well as occurrences of two known nectar plants,Hymenoxys lemmonii(Lemmon's bitterweed) andErigeron clokeyi(Clokey fleabane) (SWCA 2008, pp. 2 and 5; Pinyon 2011, p. 11). The total area of the South Loop Trail location is 60 acres (ac) (24 hectares (ha)).

    We consider the Las Vegas Ski and Snowboard Resort location (LVSSR) in Upper Lee Canyon (Location 2 in Table1) to be “known occupied” because: (1) The butterfly was first recorded at LVSSR in 1963 (Austin 1980, p. 22) and has been consistently observed at LVSSR every year between 1995 and 2006 (with the exception of 1997 when no surveys were performed (Service 2007, pp. 1-2)) and in 2010 (Thompson and Garrett 2010, p. 5); and (2) the ski runs contain two areas of high-quality butterfly habitat in accordance with host plant densities of 10 plants per square meter as described in Weisset al.(1997, p. 31). These areas are LVSSR #1 (2.4 ac (0.97 ha)) and LVSSR #2 (1.3 ac (0.53 ha)), which have been mapped using a global positioning system unit and field-verified. Thus, across its current range, the Mt. Charleston blue butterfly is known to persistently occupy less than 64 ac (26 ha) of known occupied habitat.

    Status and Trends

    While there are no estimates of the size of the Mt. Charleston blue butterfly population, the best available information indicates a declining trend for this subspecies, as discussed below. Prior to 1980, descriptions of the Mt. Charleston blue butterfly status and trends were characterized as usually rare (Austin and Austin 1980, p. 30). The Mt. Charleston blue butterfly is known to be rare because few have been observed since the 1920's, even though there have been many collections and studies of butterflies in the Spring Mountains, particularly since the 1950's (Boyd and Austin 1999, p. 2).

    It is important to note that year-to-year fluctuations in population numbers do occur (most likely due to variations in precipitation and temperature that affect both the Mt. Charleston blue butterfly and its larval host plant (Weisset al.1997, pp. 2-3 and 31-32)). However, the failure to detect Mt. Charleston blue butterflies at many of the known historical locations during the past 20 years, especially in light of increased survey efforts in recent years (since 2006), indicates a reduction in the butterfly's distribution and likely decrease in total population size. In addition, five additional locations may be presumed extirpated in 2015, if surveys continue to fail to detect Mt. Charleston blue butterflies (these include Youth Camp, Gary Abbott, Lee Meadows, Bonanza Trail, and Mummy Spring, Table 1). Mt. Charleston blue butterflies were last observed at these sites in 1995, which was the last year reported as a good year (Boyd and Murphy 2008, p. 22) for Mt. Charleston blue butterflies, as indicated by the numbers observed at LVSSR (121 counted during 2 surveys each of 2 areas), and presence detected at 7 other locations (Weiss 1996, p. 4; Weisset al.1997, Table 2).

    Survey information indicates that the numbers of recently observed Mt. Charleston blue butterflies are extremely low because butterflies have become increasingly difficult to detect. Zonneveldet al.(2003) determined that observable population size is interdependent with survey days and detection probability. Thus, the decreasing observations of Mt. Charleston blue butterflies after repeated visits in any year, after multiple years of surveying, indicates a declining and smaller population. In 2006, surveys within presumed occupied habitat at LVSSR located one individual butterfly adjacent to a pond that holds water for snowmaking (Newfields 2006, pp. 10, 13, and C5). In a later report, the accuracy of this observation was questioned and considered inaccurate (Newfields 2008, p. 27).

    In 2006, Boyd (2006, pp. 1-2) conducted focused surveys for the subspecies at nearly all previously known locations and within potential habitat along Griffith Peak, North Loop Trail, Bristlecone Trail, and South Bonanza Trail but did not observe the butterfly at any of these locations. In 2007, surveys were again conducted in previously known locations in Upper Lee Canyon and LVSSR, but no butterflies were recorded (Datasmiths 2007, p. 1; Newfields 2008, pp. 21-24). In 2007, two Mt. Charleston blue butterflies were sighted on different dates at the same location on the South Loop Trail in Upper Kyle Canyon (Kingsley 2007, p. 5). In 2008, butterflies were not observed during focused surveys of Upper Lee Canyon and the South Loop Trail (Boyd and Murphy 2008, pp. 1-3; Boyd 2008, p. 1; SWCA 2008, p. 6), although it is possible that adult butterflies may have been missed on the South Loop Trail because the surveys were performed very late in the season. No formal surveys were conducted in 2009; however, no individuals were observed during the few informal attempts made to observe the species (Service 2009).

    In 2010, the Mt. Charleston blue butterfly was observed during surveys at LVSSR and the South Loop Trail area. One adult was observed in Lee Canyon at LVSSR on July 23, 2010, but no other adults were detected at LVSSR during surveys conducted on August 2, 9, and 18, 2010 (Thompson and Garrett 2010, pp. 4-5). The Mt. Charleston blue butterfly was not observed at LVSSR in 2011 (Thompsonet al.2012, p. 99). Adults were most recently observed in 2010 and 2011 at the South Loop Trail area. According to reports from surveys conducted in July and August of 2011 at the South Loop Trail area (Thompsonet al.2012, p. 99; Pinyon 2011, pp. 17-19), the highest total number of adults counted among the days this area was surveyed was 17 on July 28, 2010, and 13 on August 12, 2011 (Pinyon 2011, p. 17). Final reports have not been completed by Thompsonet al.for the 2011 surveys and the results here are considered preliminary. Based on the available survey information, the low number of sightings in recent years is likely the result of declining population size.

    Habitat

    Weisset al.(1997, pp. 10-11) describe the natural habitat for the Mt. Charleston blue butterfly as relatively flat ridgelines above 2,500 m (8,200 ft), but isolated individuals have been observed as low as 2,000 m (6,600 ft). Boyd and Murphy (2008, p. 19) indicate that areas occupied by the subspecies featured exposed soil and rock substrates with limited or no canopy cover or shading and flat to mild slopes. Like most butterfly species, the Mt. Charleston blue butterfly is dependent on plants both during larval development (larval host plants) and the adult butterfly flight period (nectar plants). The Mt. Charleston blue butterfly requires areas that supportAstragalus calycosusvar.calycosus,the only known larval host plant for the subspecies (Weisset al.1994, p. 3; Weisset al.1997, p. 10; Datasmiths 2007, p. 21), as well as primary nectar plants.A. c.var.calycosusandErigeron clokeyiare the primary nectar plants for the subspecies; however, butterflies have also been observed nectaring onHymenoxys lemmoniiandAstersp. (Weisset al.1994, p. 3; Boyd 2005, p. 1; Boyd and Murphy 2008, p. 9).

    The best available habitat information relates mostly to the Mt. Charleston blue butterfly's larval host plant, with little to no information available characterizing the butterfly's interactions with its known nectar plants or other elements of its habitat; thus, the habitat information discussed in this document centers onAstragalus calycosusvar.calycosus.Studies are currently underway to better understand the habitat requirements and preferences of the Mt. Charleston blue butterfly (Thompsonet al.2011, p. 99).Astragalus c.var.calycosusis a small, low-growing, perennial herb that has been observed growing in open areas between 5,000 to 10,800 ft (1,520 to 3,290 m) in subalpine, bristlecone, and mixed-conifer vegetation communities of the Spring Mountains (Nachlingerand Leary 2007, p. 36). Within the alpine and subalpine range of the Mt. Charleston blue butterfly, Weisset al.(1997, p. 10) observed the highest densities ofA. c.var.calycosusin exposed areas and within canopy openings and lower densities in forested areas.

    Weisset al.(1997, p. 31) describe favorable habitat for the Mt. Charleston blue butterfly as having high densities (more than 10 plants per square meter) ofAstragalus calycosusvar.calycosus.Weisset al.(1995, p. 5) and Datasmiths (2007, p. 21) indicate that, in some areas, butterfly habitat may be dependent on old or infrequent disturbances that create open areas. Vegetation cover within disturbed patches naturally becomes higher over time through succession, gradually becoming less favorable to the butterfly. Therefore, we conclude that open areas with relatively little grass cover and visible mineral soil and high densities of host plants support the highest densities of butterflies (Boyd 2005, p. 1; Service 2006a, p. 1). During 1995, an especially high-population year (a total of 121 butterflies were counted during surveys of 2 areas at LVSSR on 2 separate dates, where each survey for each area takes approximately 22 minutes to complete for a single observer (Weiss 1996, p. 4)), Mt. Charleston blue butterflies were observed in small habitat patches and in open forested areas whereA. c. var. calycosuswas present in low densities, on the order of 1 to 5 plants per square meter (Weisset al.1997, p. 10; Newfields 2006, pp. 10 and C5). Therefore, areas with lower densities of the host plant may also be important to the subspecies, as these areas may be intermittently occupied or may be important for dispersal.

    Fire suppression and other management practices have likely limited the formation of new habitat for the Mt. Charleston blue butterfly, as discussed below. The Forest Service began suppressing fires on the Spring Mountains in 1910 (Entrix 2007, p. 111). Throughout the Spring Mountains, fire suppression has resulted in higher densities of trees and shrubs (Amell 2006, pp. 2-3) and a transition to a closed-canopy forest with shade-tolerant understory species (Entrix 2007, p. 112) that is generally less suitable for the Mt. Charleston blue butterfly. Boyd and Murphy (2008, pp. 23 and 25) hypothesized that the loss of presettlement vegetation structure over time has caused the Mt. Charleston blue butterfly's metapopulation dynamics to collapse in Upper Lee Canyon. Similar losses of suitable butterfly habitat in woodlands and their negative effect on butterfly populations have been documented (Thomas 1984, pp. 337-338). The disturbed landscape at LVSSR provides important habitat for the Mt. Charleston blue butterfly (Weisset al.1995, p. 5; Weisset al.1997, p. 26). Periodic maintenance (removal of trees and shrubs) of the ski runs has effectively arrested forest succession on the ski slopes and serves to maintain conditions favorable to the Mt. Charleston blue butterfly, and to its host and nectar plants. However, the ski runs are not specifically managed to benefit habitat for this subspecies, and operational activities regularly modify Mt. Charleston blue butterfly habitat or prevent host plants from reestablishing in disturbed areas.

    Biology

    The Mt. Charleston blue butterfly has been described as biennial where it diapauses as an egg the first winter and as a larvae near maturity the second winter (Ferris and Brown, pp. 203-204; Scott 1986, p. 411); however, Emmel and Shields (1978, p. 132) suggested that diapause was passed as partly grown larva because freshly hatched eggshells were found near newly laid eggs (indicating that the eggs do not overwinter). The Mt. Charleston blue butterfly is generally thought to diapause at the base of its larval host plant,Astragalus calycosusvar.calycosus,or in the surrounding substrate (Emmel and Shields 1978, p. 132). The pupae of some butterfly species are known to persist in diapause up to 5 to 7 years (Scott 1986, p. 28). The number of years the Mt. Charleston blue butterfly can remain in diapause is unknown. Experts have speculated that the Mt. Charleston blue butterfly may only be able to diapause for two seasons (Murphy 2006, p. 1; Boyd and Murphy 2008, p. 21). However, in response to unfavorable environmental conditions, it is hypothesized that a prolonged diapause period may be possible (Scott 1986, pp. 26-30; Murphy 2006, p. 1; Datasmiths 2007, p. 6; Boyd and Murphy 2008, p. 22).

    The typical flight and breeding period for the butterfly is early July to mid-August with a peak in late July, although the subspecies has been observed as early as mid-June and as late as mid-September (Austin 1980, p. 22; Boyd and Austin 1999, p. 17; Forest Service 2006a, p. 9). As with most butterflies, the Mt. Charleston blue butterfly typically flies during sunny conditions, which are particularly important for this subspecies given the cooler air temperatures at high elevations (Weisset al.1997, p. 31). Excessive winds also deter flight of most butterflies, although Weisset al.(1997, p. 31) speculate that this may not be a significant factor for the Mt. Charleston blue butterfly given its low-to-the-ground flight pattern.

    Like all butterfly species, both the phenology (timing) and number of Mt. Charleston blue butterfly individuals that emerge and fly to reproduce during a particular year are reliant on the combination of many environmental factors that may constitute a successful (“favorable”) or unsuccessful (“poor”) year for the subspecies. Other than observations by surveyors, little information is known regarding these aspects of the subspecies' biology, since the key determinants for the interactions among the Mt. Charleston blue butterfly's flight and breeding period, larval host plant, and environmental conditions have not been specifically studied. Observations indicate that above- or below-average precipitation, coupled with above- or below-average temperatures, influence the phenology of this subspecies (Weisset al.1997, pp. 2-3 and 32; Boyd and Austin 1999, p. 8) and are likely responsible for the fluctuation in population numbers from year to year (Weisset al.1997, pp. 2-3 and 31-32).

    Most butterfly populations exist as regional metapopulations (Murphyet al.1990, p. 44). Boyd and Austin (1999, pp. 17 and 53) indicate this is true of the Mt. Charleston blue butterfly. Small habitat patches tend to support smaller butterfly populations that are frequently extirpated by events that are part of normal variation (Murphyet al.1990, p. 44). According to Boyd and Austin (1999, p. 17), smaller colonies of the Mt. Charleston blue butterfly may be ephemeral in the long term, with the larger colonies of the subspecies more likely than smaller populations to persist in “poor” years, when environmental conditions do not support the emergence, flight, and reproduction of individuals. The ability of the Mt. Charleston blue butterfly to move between habitat patches has not been studied; however, field observations indicate the subspecies has low vagility (capacity or tendency of a species to move about or disperse in a given environment), on the order of 10 to 100 meters (m) (33 to 330 feet (ft)) (Weisset al.1995, p. 9), and nearly sedentary behavior (Datasmiths 2007, p. 21; Boyd and Murphy 2008, pp. 3 and 9). Furthermore, dispersal of lycaenid butterflies, in general, is limited and on the order of hundreds of meters (Cushman and Murphy 1993, p. 40). Based on this information, the likelihood of long-distance dispersal islow for the Mt. Charleston blue butterfly, and its susceptibility to being affected by habitat fragmentation caused by forest succession is high (discussed further in Factor A).

    Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species 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; and (E) other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination. Each of these factors is discussed below.

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

    Below, we evaluate several factors that negatively impact the Mt. Charleston blue butterfly's habitat, including fire suppression, fuels reduction, succession, introduction of nonnative species, recreation, and development. We also examine available conservation measures in the form of conservation agreements and plans, which may offset some of these threats.

    Fire Suppression, Succession, and Nonnative Species

    Butterflies have extremely specialized habitat requirements (Thomas 1984, p. 337). Changes in vegetation structure and composition as a result of natural processes are a serious threat to butterfly populations because these changes can disrupt specific habitat requirements (Thomas 1984, pp. 337-341; Thomaset al.2001, pp. 1791-1796). Cushman and Murphy (1993, p. 4) determined 28 at-risk lycaenid butterfly species, including the Mt. Charleston blue butterfly, to be dependent on one or two closely related host plants. Many of these host plants are dependent on early successional environments. Butterflies that specialize on such plants must track an ephemeral resource base that itself depends on unpredictable and perhaps infrequent ecosystem disturbances. For such butterfly species, local extinction events are both frequent and inevitable (Cushman and Murphy 1993, p. 4). The Mt. Charleston blue butterfly may, in part, depend on disturbances that open up the subalpine canopy and create conditions more favorable to its host plant,Astragalus calycosusvar.calycosus,and nectar resources (Weisset al.1995, p. 5; Boyd and Murphy 2008, pp. 22-28) (see Habitat section, above).

    Datasmiths (2007, p. 21) also suggest suitable habitat patches ofAstragalus calycosusvar.calycosusare often, but not exclusively, associated with older or infrequent disturbance. Weisset al.(1995, p. 5) note that a colony once existed on the Upper Kyle Canyon Ski Area (Location 11 in Table 1), but since the ski run was abandoned no butterflies have been collected there since 1965. Boyd and Austin (2002, p. 13) observe that the butterfly was common at Lee Meadows (Location 8 in Table 1) in the 1960s, but became uncommon at the site because of succession and a potential lack of disturbance. Using an analysis of host plant density, Weisset al.(1995 p. 5) concluded that Lee Meadows does not have enough host plants to support a population over the long term (minimally 5-10 host plants per square meter). Disturbances such as fire promote open understory conditions forA. c.var.calycosusto grow and reduce fragmentation of Mt. Charleston blue butterfly habitat.

    Fire suppression in the Spring Mountains has resulted in long-term successional changes, including increased forest area and forest structure (higher canopy cover, more young trees, and more trees intolerant of fire) (Nachlinger and Reese 1996, p. 37; Amell 2006, pp. 6-9; Boyd and Murphy 2008, pp. 22-28; Dentonet al.2008, p. 21; Abellaet al.2011, pp. 10, 12). Frequent low-severity fires would have maintained an open forest structure characterized by uneven-aged stands of fire-resistantPinus ponderosa(ponderosa pine) trees (Amell 2006, p. 5) in lower elevations. The lower-elevation habitats of the Mt. Charleston blue butterfly are the most affected by fire suppression, as indicated by Provencher's 2008 Fire Regime Condition Class analysis of the Spring Mountains (p. 18); there has been an increase in area covered by forest canopy and an increase in stem densities with more trees intolerant of fire within the lower-elevation Mt. Charleston blue butterfly habitat.

    Large-diameterPinus ponderosatrees with multiple fire scars in Upper Lee and Kyle Canyons indicate that low-severity fires historically burned through mixed-conifer forests within the range of the Mt. Charleston blue butterfly (Amell 2006, p. 3). There are no empirical estimates of fire intervals or frequencies in the Spring Mountains but it is presumed to be similar toPinus ponderosaforests in other regions where it has been reported to be 4 to 20 or 2 to 39 years (Barbour and Minnich 2000 as cited in Amell 2006, p. 3; Dentonet al.2008, p. 23). Open mixed-conifer forests in the Spring Mountains were likely characterized by more abundant and diverse understory plant communities compared to current conditions (Entrix 2007, pp. 73-78). These successional changes have been hypothesized to have contributed to the decline of the Mt. Charleston blue butterfly because of reduced densities of larval and nectar plants, decreased solar radiation, and inhibited butterfly movements that subsequently determine colonization or recolonization processes (Weisset al.1997, p. 26; Boyd and Murphy 2008, pp. 22-28).

    Boyd and Murphy (2008, p. 23) note that important habitat characteristics required by Mt. Charleston blue butterfly—Astragalus calycosusvar.calycosusand preferred nectar plants occurring together in open sites not shaded by tree canopies—would have occurred more frequently across a more open forested landscape, compared to the current denser forested landscape. Not only would the changes in forest structure and understory plant communities result in habitat loss, degradation, and fragmentation for the Mt. Charleston blue butterfly across a broad spatial scale, a habitat matrix dominated by denser forest also may be impacting key metapopulation processes by reducing probability of recolonization following local population extirpations in remaining patches of suitable habitat (Boyd and Murphy 2008, p. 25).

    The introduction of forbs, shrubs, and nonnative grasses can be a threat to the butterfly's habitat because these species can compete with, and decrease, the quality and abundance of larval host plant and adult nectar sources. This has been observed for many butterfly species including the Quino checkerspot butterfly (Euphydryas editha quino) (62 FR 2313; January 16, 1997) and Fender's blue butterfly (Plebejus(=Icaricia)icarioides fenderi) (65 FR 3875; January 25, 2000). Succession, coupled with the introduction of nonnative species, is also believed to be the reason the Mt. Charleston blue butterfly is no longer present at the old town site in Kyle Canyon (Location 12 in Table 1) and at the Mt. Charleston blue butterflyholotype (the type specimen used in the original description of a species or subspecies) site in Upper Lee Canyon (Location 9 in Table 1) (Urban Wildlands Group, Inc. 2005, p. 3; Boyd and Austin 1999, p. 17).

    Introduction of nonnative species within its habitat negatively impacts the quality of the Mt. Charleston blue butterfly's habitat. As mentioned previously (see Habitat section), periodic maintenance (removal of trees and shrubs) of the ski runs has effectively arrested succession on the ski slopes and maintains conditions that can be favorable to the Mt. Charleston blue butterfly. However, the ski runs are not specifically managed to benefit habitat for this subspecies and its habitat requirements, and operational activities (including seeding of nonnative species) regularly modify Mt. Charleston blue butterfly habitat or prevent host plants from reestablishing in disturbed areas. According to Weisset al.(1995, pp. 5-6), the planting of annual grasses andMelilotus(sweetclover) for erosion control at LVSSR is a threat to Mt. Charleston blue butterfly habitat. Titus and Landau (2003, p. 1) observed that vegetation on highly and moderately disturbed areas of the LVSSR ski runs are floristically very different from natural openings in the adjacent forested areas that support this subspecies. Seeding nonnative species for erosion control was discontinued in 2005; however, because of erosion problems during 2006 and 2007, and the lack of native seed, LVSSR resumed using a nonnative seed mix, particularly in the lower portions of the ski runs (not adjacent to Mt. Charleston blue butterfly habitat) where erosion problems persist.

    The best available information indicates that, in at least four of the six locations where the Mt. Charleston blue butterfly historically occurred, suitable habitat is no longer present due to vegetation changes attributable to succession, the introduction of nonnative species, or a combination of the two.

    Recreation, Development, and Other Projects

    As discussed in theDistributionsection above, the Mt. Charleston blue butterfly is a narrow endemic subspecies that is currently known to occupy two locations and presumed to occupy eight others. One of the two areas where Mt. Charleston blue butterflies have been detected in recent years is the LVSSR. Several ground-disturbing projects occurred within Mt. Charleston blue butterfly suitable habitat at LVSSR between 2000 and 2011 (see 76 FR 12667, pp. 12672, 12673). These projects were small spatial scale (ground disturbance was less than about 10 acres each) but are known to have impacted suitable habitat and possibly impacted individual Mt. Charleston blue butterflies (eggs, larvae, pupae, or adults). In addition to these recreation development projects at LVSSR, a small area of suitable habitat and possibly individual Mt. Charleston blue butterflies were impacted by a water system replacement project in Upper Lee Canyon in 2003, and a small area of suitable habitat (less than 1 acre) was impacted by a stream restoration project at Lee Meadows in 2011. It is difficult to know the full extent of impacts to the Mt. Charleston blue butterfly's habitat as a result of these projects because Mt. Charleston blue butterfly habitat was not mapped nor were some project areas surveyed prior to implementation.

    Three future projects also may impact Mt. Charleston blue butterfly habitat in Upper Lee Canyon. These projects are summarized below:

    (1) A March 2011 Master Development Plan for LVSSR proposes to improve, upgrade, and expand the existing facilities to provide year-round recreational activities. The plan proposes to increase snow trails, beginner terrain, and snowmaking reservoir capacity and coverage, widen existing ski trails, replace and add lifts, and develop “gladed” areas for sliding that would remove deadfall timber to reduce fire hazards (Ecosign 2011, I-3—I-4, IV-5—IV-7). The plan proposes to add summer activities including lift-accessed sightseeing and hiking, nature interpretive hikes, evening stargazing, mountain biking, conference retreats and seminars, weddings, family reunions, mountain music concerts, festivals, climbing walls, bungee trampoline, beach and grass volleyball, a car rally, and other activities (Ecosign 2008, pp. I-3—I-4). Widening existing ski trails and increasing snowmaking reservoir capacity (Ecosign 2011, p. IV-5, Figure 21a) would impact the Mt. Charleston blue butterfly at a known occupied and at a presumed occupied location (Location 2 and 5 in Table 1). Summer activities would impact the Mt. Charleston blue butterfly and its known occupied and presumed occupied habitat by attracting visitors in higher numbers during the time of year when larvae and host plants are especially vulnerable to trampling (Location 2 in Table 1). The LVSSR Master Development Plan, which has been accepted by the Forest Service, considered Mt. Charleston blue butterfly habitat during development of the plan. Impacts to Mt. Charleston blue butterfly habitat from the LVSSR Master Development Plan will be addressed further during the National Environmental Policy Act (NEPA) process (discussed further in Factor D) (Forest Service 2011a, p. 3).

    (2) The Old Mill/Dolomite/McWilliams Reconstruction Projects to improve camping and picnic areas in Upper Lee Canyon are currently being planned and evaluated under NEPA (discussed further in Factor D) (Forest Service 2011c pp. 1-4). Project details are limited because planning is currently underway; however, the Service has met with the Forest Service and provided recommendations to consider for analysis of potential direct and indirect impacts of these projects to the Mt. Charleston blue butterfly and its potential habitat within or in close proximity to the project area (Datasmiths 2007, Figure 1; Forest Service 2011c, Project Map; Forest Service 2011f, pp. 1-5; Service 2011, p. 1). The recommendations provided by the Service will assist with the development of a proposed action that will avoid or minimize adverse effects to the Mt. Charleston blue butterfly and its potential habitat.

    (3) The Foxtail Group Picnic