[Federal Register Volume 76, Number 71 (Wednesday, April 13, 2011)]
[Proposed Rules]
[Pages 20613-20622]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-8824]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2010-0077; MO 92210-0-0008]


Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition To List Spring Mountains Acastus Checkerspot Butterfly as 
Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.

-----------------------------------------------------------------------

SUMMARY: We, the U.S. Fish and Wildlife Service, announce a 90-day 
finding on a petition to list the Spring Mountains acastus checkerspot 
butterfly (Chlosyne acastus robusta) as endangered under the Endangered 
Species Act of 1973, as amended (Act). Based on our review, we find 
that the petition presents substantial scientific or commercial 
information indicating that listing the Spring Mountains acastus 
checkerspot butterfly as endangered or threatened may be warranted. 
Therefore, with the publication of this notice, we are initiating a 
review of the status of the species to determine if listing the Spring 
Mountains acastus checkerspot butterfly as endangered or threatened is 
warranted. To ensure that this status review is comprehensive, we are 
requesting scientific and commercial data and other information 
regarding this subspecies. Based on the status review, we will issue a 
12-month finding on the petition, which will address whether the 
petitioned action is warranted, as provided in section 4(b)(3)(B) of 
the Act.

DATES: To allow us adequate time to conduct this review, we request 
that we receive information on or before June 13, 2011. Please note 
that if you are using the Federal eRulemaking Portal (see ADDRESSES 
section below), the deadline for submitting an electronic comment is 
Eastern Standard Time on this date. After June 13, 2011, you must 
submit information directly to the Nevada Fish and Wildlife Office (see 
FOR FURTHER INFORMATION CONTACT section below). Please note that we 
might not be able to address or incorporate information that we receive 
after the above requested date.

ADDRESSES: You may submit information by one of the following methods:
    <bullet> Electronically: Go to the Federal eRulemaking Portal: 
http://www.regulations.gov. In the Keyword box, enter Docket No. FWS-
R8-ES-2010-0077, which is the docket number for this rulemaking. Then, 
in the Search panel on the left side of the screen, under the Document 
Type heading, click on the Proposed Rules link to locate this document. 
You may submit a comment by clicking on ``Send a Comment or 
Submission.''
    <bullet> By hard copy: Submit by U.S. mail or hand-delivery to: 
Public Comments Processing, Attn: FWS-R8-ES-2010-0077; Division of 
Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 
N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.
    We will post all information we receive on http://www.regulations.gov. This generally means that we will post any 
personal information you provide us (see the Request for Information 
section below for more details).

FOR FURTHER INFORMATION CONTACT: Jill Ralston, Deputy State Supervisor, 
U.S. Fish and Wildlife Service, Nevada Fish and Wildlife Office, 4701 
North Torrey Pines Drive, Las Vegas, NV 89130; by telephone 702-515-
5230; or by facsimile to 702-515-5231. If you use a telecommunications 
device for the deaf (TDD), please call the Federal Information Relay 
Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Request for Information

    When we make a finding that a petition presents substantial 
information indicating that listing a species may be warranted, we are 
required to promptly review the status of the species (status review). 
For the status review to be complete and based on the best available 
scientific and commercial information, we request information on the 
Spring Mountains acastus checkerspot butterfly from governmental 
agencies, Native American Tribes, the scientific community, industry, 
and any other interested parties. We seek information on:
    (1) The subspecies' 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 subspecies, its 
habitat, or both.
    (2) The factors that are the basis for making a listing/delisting/
downlisting determination for a species under section 4(a) of the 
Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et 
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.

[[Page 20614]]

    If, after the status review, we determine that listing the Spring 
Mountains acastus checkerspot butterfly is warranted, we will propose 
critical habitat (see definition in section 3(5)(A) of the Act), under 
section 4 of the Act, to the maximum extent prudent and determinable at 
the time we propose to list the subspecies. Therefore, within the 
geographical range currently occupied by the Spring Mountains acastus 
checkerspot butterfly, we request data and information on:
    (1) What may constitute ``physical or biological features essential 
to the conservation of the species'';
    (2) Where these features are currently found; and
    (3) Whether any of these features may require special management 
considerations or protection.
    In addition, we request data and information on ``specific areas 
outside the geographical area occupied by the species'' that are 
``essential to the conservation of the species.'' Please provide 
specific comments and information as to what, if any, critical habitat 
you think we should propose for designation if the subspecies is 
proposed for listing, and why such habitat meets the requirements of 
section 4 of the Act.
    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.
    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. Section 
4(b)(1)(A) of the Act directs that determinations as to whether any 
species is an endangered or threatened species must be made ``solely on 
the basis of the best scientific and commercial data available.''
    You may submit your information concerning this status review by 
one of the methods listed in the ADDRESSES section. We will not accept 
comments sent by e-mail or fax or to an address not listed in the 
ADDRESSES section of this document. If you submit information via 
http://www.regulations.gov, your entire submission--including any 
personal identifying information--will be posted on the Web site. If 
you submit a hardcopy that includes personal identifying information, 
you may request at the top of your document that we withhold this 
personal identifying information from public review. However, we cannot 
guarantee that we will be able to do so. We will post all hardcopy 
submissions on http://www.regulations.gov.
    Information and supporting documentation that we received and used 
in preparing this finding is available for you to review at http://www.regulations.gov, or you may make an appointment during normal 
business hours at the U.S. Fish and Wildlife Service, Nevada Fish and 
Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

Background

    Section 4(b)(3)(A) of the Act requires that we make a finding on 
whether a petition to list, delist, or reclassify a species presents 
substantial scientific or commercial information indicating that the 
petitioned action may be warranted. We are to base this finding on 
information provided in the petition, supporting information submitted 
with the petition, and information otherwise available in our files. To 
the maximum extent practicable, we are to make this finding within 90 
days of our receipt of the petition, and publish our notice of the 
finding promptly in the Federal Register.
    Our standard for substantial scientific or commercial information 
within the Code of Federal Regulations (CFR) with regard to a 90-day 
petition finding is ``that amount of information that would lead a 
reasonable person to believe that the measure proposed in the petition 
may be warranted'' (50 CFR 424.14(b)). If we find that substantial 
scientific or commercial information was presented, we are required to 
promptly conduct a species status review, which we subsequently 
summarize in our 12-month finding.

Petition History

    On September 18, 2009, we received a petition, dated September 16, 
2009, from Bruce M. Boyd, requesting that the Spring Mountains acastus 
checkerspot butterfly be listed as endangered under the Act (Boyd 
2009). The petition clearly identified itself as such and included the 
requisite identification information for the petitioner, as required by 
50 CFR 424.14(a). In a November 24, 2009, letter to petitioner Bruce M. 
Boyd, we responded that we reviewed the information presented in the 
petition and determined that issuing an emergency regulation 
temporarily listing the butterfly under section 4(b)(7) of the Act was 
not warranted (Service 2009, p. 1). We also stated that funding was 
secured and that we anticipated making an initial finding in Fiscal 
Year 2010 as to whether the petition contains substantial information 
indicating that the action may be warranted. This finding addresses the 
petition.

Previous Federal Actions

    In 1991 and 1994, the U.S. Fish and Wildlife Service (Service) 
included the Spring Mountains acastus checkerspot butterfly in a 
compilation of taxa that were to be reviewed for possible addition to 
the Lists of Endangered and Threatened Wildlife and Plants (56 FR 
58804, November 21, 1991; 59 FR 58982, November 15, 1994). In both 
years the Spring Mountains acastus checkerspot butterfly was assigned 
to a ``Category 2'' species. Such a designation indicated that 
proposing to list was possibly appropriate, but additional information 
on biological vulnerability and threats were needed to support the 
preparation of a proposed rule. The trend for Spring Mountains acastus 
checkerspot butterfly was described as ``Unknown.'' These notices 
stressed that species in this category were not proposed for listing, 
nor were there any plans to list unless supporting information became 
available.
    In the February 28, 1996, Candidate Notice of Review (61 FR 7595), 
we adopted a single category of candidate species defined as follows: 
``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 
matching this definition were known as Category 1 candidates for 
listing. Thus, the Service no longer considered Category 2 species 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 as candidates was designed to reduce confusion about the 
status of these species and to clarify that we no longer regarded these 
species as candidates for listing.

Species Information

    The Spring Mountains acastus checkerspot butterfly (Chlosyne 
acastus robusta) is a subspecies of sagebrush checkerspot butterfly 
(Chlosyne acastus) belonging to the Nymphalidae (brush-footed 
butterflies) family. Synonyms of the genera Chlosyne have included 
Charidryas and Thessalia (Opler and Warren 2003, pp. 35-36). Early 
taxonomic assessments of specimens C. a. robusta ascribed it to C. a. 
vallismortis (= C. palla vallismortis; Austin 1981, p. 71). Later 
interpretations suggested that it was more closely aligned to C. 
acastus (Austin 1985, p. 108). Further evaluations resulted in 
recognition of

[[Page 20615]]

the Spring Mountains acastus checkerspot butterfly as a distinct 
subspecies (Austin 1998a, p. 576). There are nine subspecies of 
sagebrush checkerspot butterflies described for North America (Pelham 
2008, pp. 379-380), of which four (C. a. acastus, C. a. dorothyi, C. a. 
robusta, and C. a. neumoegeni) occur in Nevada (Austin 1998b, p. 842).
    The Spring Mountains acastus checkerspot butterfly is known only 
from the Spring Mountains in Clark and Nye Counties, Nevada (Austin 
1998a, p. 577), at elevations ranging from minimums near 1,800 meters 
(m) to maximums at 2,700 m (5,900-8,900 feet (ft); Weiss et al. 1997, 
p. 17). In low elevation desert areas adjacent to the distribution of 
Spring Mountains acastus checkerspot butterfly, a similar looking 
subspecies, C. a. neumoegeni, may occur (Austin 1998a, p. 577), and is 
likely the nearest subspecies spatially. The majority of observations 
and habitat for the Spring Mountains acastus checkerspot butterfly 
occur within the Spring Mountains National Recreation Area, which is 
managed by the U.S. Department of Agriculture, Forest Service 
(hereafter referred to as Forest Service), Humboldt-Toiyabe National 
Forest. However, one colony occurs on private property bordered by 
Forest Service managed lands, and an incidental observation at another 
location has been documented on lands managed by the U.S. Department of 
the Interior, Bureau of Land Management.
    Sagebrush checkerspot butterfly habitat is described as dry washes 
in sagebrush-juniper woodland, oak or mixed conifer woodland, and 
streambeds (Opler 1999, p. 199). Elevations used by Spring Mountains 
acastus checkerspot butterfly coincide with the intergraded upper 
elevation of Pinus monophylla-Juniperus osteosperma (pi[ntilde]yon-
juniper) communities at 1,250-2,500 m (4,100-8,200 ft) and the lower 
elevation Abies concolor-Pinus ponderosa var. scopulorum (white fir-
ponderosa pine) communities at 2,000-2,530 m (6,560-8,300 ft) (Niles 
and Leary 2007, pp. 5-6). Open vegetation communities associated with 
previous fire disturbances appear to be the preferred habitat (Boyd and 
Austin 2002, p. 5). Washes and linear features are used primarily as 
mating sites during the flight season (Boyd and Austin 2001, p. 6; Boyd 
and Austin 2002, p. 5).
    Spring Mountains acastus checkerspot butterfly males may seek 
females all day by perching and sometimes patrolling gulches (Scott 
1986, p. 307; Kingsley 2008, pp. 7-8). Males may perch on several 
projecting objects in the same area such as rocks or branches (Scott 
1986, pp. 46-47, 307; Kingsley 2008, pp. 4, 7-8). At these sites males 
behave territorially by remaining in the same area and pursuing any 
other butterflies or insects that come within a zone of a few square 
meters around the male and continue this behavior towards the intruding 
animal until it leaves (Boyd and Austin 2001, p. 5; Boyd and Austin 
2002, p. 5; Kingsley 2008, pp. 4, 7-8). During a brief flight season 
(Weiss et al. 1997, pp. 6, 37), females remain at the site long enough 
to find a male to mate with, and then leave the area to oviposit (Boyd 
and Austin 2001, p. 6; Boyd and Austin 2002, p. 5).
    The flight season of the Spring Mountains acastus checkerspot is 
between mid-May and mid-July (Weiss et al. 1997, pp. 6, 37; Austin 
1998a, p. 576; Boyd 2004, pp. 1-2), peaking near the later part of June 
(Weiss et al. 1997, pp. 6, 37; Boyd and Austin 1999, p. 20; Boyd and 
Austin 2002, p. 4; Boyd 2004, p. 8). Distances moved during flight 
periods have not been documented, although Schrier et al. (1976, p. 
285) observed that a related species, the northern checkerspot 
butterfly (C. palla), could move as far as 1.6 kilometers (1 mile). 
During the flight season, Spring Mountains acastus checkerspot adults 
have been observed nectaring on Eriodictyon angustifolium (yerba 
santa), Heliomeris multiflora var. nevadensis (= Viguiera multiflora; 
Nevada golden-eye), Packera multilobata (= Senecio multilobatus; 
lobeleaf groundsel), unknown Ceanothus sp. (ceanothus species), unknown 
Melilotus sp. (clover species), Penstemon palmeri (Palmer penstemon), 
and an unknown Apocynum sp. (dogbane species) (Weiss et al. 1995, p. 9; 
Boyd et al. 2000a, p. 6; Jones & Stokes 2007a, p. 4).
    Chrysothamnus viscidiflorus has been documented as a larval host 
plant (Boyd and Austin 2002, p. 2; Austin and Leary 2008, p. 99), and 
according to the petition, is common and widely distributed in the 
range (Boyd 2009, p. 1). Common names used interchangeably among 
subspecies of C. viscidiflorus have included Douglas rabbitbrush, 
chamisa, green rabbitbrush, yellow rabbitbrush, viscid rabbitbrush, 
sticky leaved rabbitbrush, downy rabbitbrush, and narrow leaved 
rabbitbrush (Stubbendieck et al. 2003, p. 249; Niles and Leary 2007, p. 
19). Three subspecies of C. viscidiflorus have been documented in the 
Spring Mountains, including C. v. lanceolatus (variously known as 
viscid rabbitbrush, sticky leaved rabbitbrush, and yellow rabbitbrush), 
C. v. puberulus (downy rabbitbrush), and C. v. viscidiflorus (variously 
known as viscid rabbitbrush, sticky leaved rabbitbrush, and narrow 
leaved rabbitbrush) (Niles and Leary 2007, p. 19). It is unknown which 
of these subspecies of C. viscidiflorus are used as a larval host by 
Spring Mountains acastus checkerspot butterfly. Of butterfly host 
plants described by Weiss et al. (1997, Figure 4), Chrysothamnus 
viscidiflorus tends to be found in areas with the lowest percentages of 
tree canopy cover (mean of 17 percent) compared to other host plant 
species.
    Ericameria nauseosa (= Chrysothamnus nauseosus, rubber rabbitbrush) 
also is suspected of being a larval host plant (Weiss et al. 1997, p. 
6). Boyd and Austin (1999, pp. 20-21) attempted to feed E. nauseosa to 
Spring Mountains acastus checkerspot larvae unsuccessfully and reported 
that their results were inconclusive. However, they reported that other 
subspecies of sagebrush checkerspot butterflies used Acamptopappus sp. 
(goldenhead) and Xylorhiza sp. (woodyaster) as larval host plants 
(Austin and Austin 1980, as cited in Boyd and Austin 1999, p. 21).
    Clusters of eggs are laid on the underside of host leaves and 
sometimes on flower buds (Scott 1986, p. 307). After the eggs hatch, 
the young larvae cluster together on leaves or flowers (Scott 1986, p. 
307). Similar to other members of the subfamily Nymphalinae and closely 
related subspecies, Spring Mountains acastus checkerspot larvae likely 
hibernate during the winter and may diapause [a period of arrested 
growth or reduced physiological activity, commonly induced by a 
seasonal change in photoperiod (i.e., day-length)] for many months or 
years (Scott 1986, pp. 27, 307).
    Weiss et al. (1997, p. 2) indicated that butterfly populations are 
highly dynamic, and from year to year, butterfly distributions can be 
highly variable. Butterflies may be restricted to moist and cool 
habitats during dry, warm periods, potentially expanding their 
distribution during periods marked by cooler and moister conditions 
(Weiss et al. 1997, pp. 2-3). Some species, such as the Spring 
Mountains acastus checkerspot butterfly, may exist as a metapopulation 
within the Spring Mountains (Weiss et al. 1997, p. 3). If this is the 
case, maintenance of dispersal corridors and unoccupied habitats is an 
important management consideration (Weiss et al. 1997, p. 3).
    The Spring Mountains acastus checkerspot butterfly occurs 
throughout the Spring Mountains and has been observed in 17 areas 
(Table 1). However, the number of occupied areas reported in past 
studies varies (12 occupied areas

[[Page 20616]]

were reported in Boyd and Austin 1999, p. 20) based on how observations 
are spatially grouped. Four of these areas (Trough Spring, Kyle Canyon, 
Griffith Peak Trail/Harris Spring Road/Harris Mountain Road, and Potosi 
Mountain/Mt. Potosi/Boy Scout Camp) are referred to interchangeably as 
colonies or population sites (Boyd & Austin 1999, pp. 9, 20-21; Boyd 
and Austin 2002, pp. 5, 13; Boyd 2004, pp. 2-3). Currently, only four 
colonies are known to exist. However, the increased existence of 
incidental sighting areas and the potential subsequent dispersal of 
individuals may indicate the presence of additional unknown colonies 
(Boyd and Austin 1999, pp. 60-61; Boyd et al. 2000, p. 10) (Table 1).

 Table 1--Areas Where Spring Mountains Acastus Checkerspot Observations
                          Have Been Documented
  [Areas ordered to begin with the most northern and end with the most
                                southern]
------------------------------------------------------------------------
            Observation area                   First year  observed
------------------------------------------------------------------------
Mt. Stirling...........................  1983.
Big Timber Spring......................  1995 or before.
Wheeler Pass Road......................  1987.
Trough Spring *........................  2001.
McFarland Spring/Whisky Spring/Camp      2003.
 Bonanza.
Willow Spring/Willow Creek.............  1979.
Clark Canyon...........................  1994.
Foxtail Canyon.........................  1998.
Deer Creek & Picnic Area...............  1965.
Deer Creek Road (Telephone Canyon side)  1981 or 87.
Kyle Canyon--lower.....................  1996 or before.
Kyle Canyon--middle *..................  1950.
Kyle Canyon--upper.....................  1987.
Griffith Peak Trail/Harris Spring Road/  1990.
 Harris Mountain Road *.
Coal Spring............................  1992.
Switchback Spring......................  2003.
Potosi Mountain/Mt. Potosi/Boy Scout     1995.
 Camp *.
------------------------------------------------------------------------
* Asterisk indicates a colony. Colonies are isolated populations (Scott
  1986, p. 108) based on mate locating behavior (Boyd and Austin 2002,
  p. 5; Boyd 2009, p. 1) of one or more males observed over a period of
  time and represent more than one incidental observation or sighting.
Sources: Weiss et al. 1995, pp. 4 and 19; Weiss et al. 1997, pp. 6-7,
  47; Boyd and Austin 1999, pp. 19-21; Boyd 2004, pp. 2-3; Nevada
  Natural Heritage Program 2009.

    A colony is ``a local, isolated population'' (Scott 1986, p. 108). 
Past researchers defined colonies of Spring Mountains acastus 
checkerspot butterflies based on the mate locating behavior of males, 
also referred to as mate locating sites (Boyd and Austin 2002, p. 5; 
Boyd 2009, p. 1). The remaining 13 areas are referred to as incidental 
observations or sighting areas (Boyd and Austin 2001, p. 2; Boyd and 
Austin 2002, p. 3; Boyd 2004, p. 3), where intermittent observations of 
a few butterflies were recorded at a location. The areas where the 
Spring Mountains acastus checkerspot butterfly has been observed in a 
colony or sighting area represent the overall known population of the 
subspecies.
    The largest known colony occurs at Griffith Peak Trail/Harris 
Spring Road/Harris Mountain Road, and was first documented as a 
sighting area in 1990 and later described as a potential colony in 1999 
(Boyd and Austin 1999, p. 20). The Trough Spring colony was first 
identified in 2001 (Boyd and Austin 2002, p. 5). Boyd (2004, p. 3) 
stated that a single male observed at Willow Spring/Willow Creek in 
2003 may have dispersed from Trough Spring or another unknown colony, 
due to its not being sighted in the area since the 1980s. The Spring 
Mountains acastus checkerspot butterfly was first documented at Potosi 
Mountain/Mt. Potosi/Boy Scout Camp in 1995 (Weiss et al. 1995, p. 6), 
and was described as a colony for the first time in 2000 (Boyd et al. 
2000a, p. 4).
    DataSmiths (2007, p. 17) concluded that absence of adults at a site 
does not necessarily equate to ephemeral occupation or extirpation. 
Observations in areas reported for the Spring Mountains acastus 
checkerspot butterfly illustrate this. Boyd et al. (2000a, p. 4) 
searched 17 areas for the Spring Mountains acastus checkerspot 
butterfly in 1999; these 17 areas consisted of 8 historical and 9 
potential sites. Spring Mountains acastus checkerspot butterflies were 
observed at five of the eight historical sites visited and two of these 
were described as potential new colonies. In later reports of surveys 
occurring in 2003, the Spring Mountains acastus checkerspot butterfly 
was observed again in the Willow Spring/Willow Creek area (Boyd 2004, 
pp. 2-3), where it was not observed during surveys in 1999 (Boyd and 
Austin 1999, p. 98-Table 7). Similarly, in 2003, the Spring Mountains 
acastus checkerspot butterfly also was observed in the McFarland 
Spring/Whisky Spring/Camp Bonanza area for the first time (Boyd 2004, 
p. 2), even though it was not observed there during previous surveys in 
1998 (Boyd and Austin 1999, p. 104-Table 12). These examples 
demonstrate that not seeing individuals at a site during surveys does 
not necessarily equate with extirpation because adult surveys will not 
detect diapausing (in a physiological state of dormancy) larvae, and 
short adult flight periods coupled with low numbers may drastically 
reduce the likelihood of observing Spring Mountains acastus checkerspot 
butterflies.
    Yearly population variation of the Spring Mountains acastus 
checkerspot butterfly also is expressed by variation in the numbers of 
observed individuals during repeat surveys at the same location (Table 
2). At the Griffith Peak Trail/Harris Spring Road/Harris Mountain Road 
site, surveys from 2000 and 2001 revealed that the highest total number 
of individuals observed on a single day increased from 19 to 104. In 
2003, the highest number observed on a single day at the same site 
decreased to 27. In a 2006 interview with the petitioner, Boyd reported 
that the Spring Mountains acastus checkerspot butterfly had ``done 
better'' than other endemic species and had ``good numbers'' at 
Griffith Peak Trail/Harris Spring Road/Harris Mountain Road (Boyd 2006, 
pers. comm.), as well as at

[[Page 20617]]

Potosi Mountain/Mt. Potosi/Boy Scout Camp (Boyd 2006, p. 2). At 
locations where it was observed in 2006, the petition states that the 
butterfly appeared to be in ``appropriate'' numbers (Boyd 2006, p. 2). 
These observations support the conclusions of Weiss et al. (1997, p. 2) 
of highly dynamic butterfly populations where observations may occur 
periodically throughout a species' range, and populations at colony 
sites may fluctuate as indicated by monitoring counts.

                     Table 2--Summary of Monitoring Results of Spring Mountains Acastus Checkerspot Butterfly at Three Colony Sites
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Year                    1999            2000            2001           2002           2003           2006           2007           2008
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kyle Canyon (middle):
    Highest <greek-i>/day.....  5.............  6.............  8............  6............  7............  4............  1............  4.
    Highest <greek-i> male/day  4.............  6.............  8............  6............  7............  4............  1............  4.
    Highest <greek-i> female/   1.............  1.............  1............  0............  1............  0............  0............  0.
     day.
    <greek-i> Visits..........  11............  9.............  6............  4............  4............  1............  6............  8.
    Peak date(s)..............  June 19.......  June 15 & 30..  June 18......  June 24......  June 10......  June 21......  June 13 & 21.  June 24.
Griffith Peak Trail/Harris
 Spring Road/Harris Mountain
 Road:
    Highest <greek-i>/day.....  ..............  19............  104..........  50...........  27...........
    Highest <greek-i> male/day  ..............  12............  78...........  43...........  17...........
    Highest <greek-i> female/   ..............  5.............  26...........  9............  10...........
     day.
    <greek-i> Visits..........  ..............  9.............  5............  5............  4............
    Peak date.................  ..............  June 11.......  June 18......  June 20......  June 29......
Trough Spring:
    Highest <greek-i>/day.....  ..............  ..............  .............  20...........  41...........
    Highest <greek-i> male/day  ..............  ..............  .............  18...........  40...........
    Highest <greek-i> female/   ..............  ..............  .............  7............  3............
     day.
    <greek-i> Visits..........  ..............  ..............  .............  3............  5............
    Peak date.................  ..............  ..............  .............  June 18......  June 1.......
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sources: (Boyd 2004, p. 8; Jones and Stokes 2007a, p. 4; Jones and Stokes 2007b, p. 3; Kingsley 2008, p. 3).

Evaluation of Information for This Finding

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations at 50 CFR 424 set forth the procedures for adding a species 
to, or removing a species from, the Federal Lists of Endangered and 
Threatened Wildlife and Plants. A species may be determined to be an 
endangered or threatened species due to one or more of the five factors 
described in section 4(a)(1) of the Act:
    (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 considering what factors might constitute threats, we must look 
beyond the exposure of the species to a particular factor to evaluate 
whether the species may respond to that 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 we attempt 
to determine how significant a threat it is. The threat may be 
significant if it drives, or contributes to, the risk of extinction of 
the species such that the species may warrant listing as endangered or 
threatened as those terms are defined by the Act. The identification of 
factors that could impact a species negatively may not be sufficient to 
compel a finding that substantial information has been presented 
suggesting that listing may be warranted. The information should 
contain evidence or the reasonable extrapolation that any factor(s) may 
be an operative threat that acts on the species to the point that the 
species may meet the definition of endangered or threatened under the 
Act.
    In making this 90-day finding, we evaluated whether information 
regarding the threats to the Spring Mountains acastus checkerspot 
butterfly, as presented in the petition and other information available 
in our files, is substantial, thereby indicating that the petitioned 
action may be warranted. Our evaluation of this information is 
presented below.
    For Factors A and E, we provide a discussion of our evaluation for 
each of the four known colonies. In addition, for Factor A, we discuss 
threats as they relate to all colonies. For Factors B, C, and D, we 
provide a discussion of our evaluation for the entire subspecies.

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

Information Provided in the Petition Concerning All Sites
    The petition states that the overall numbers of all ``covered'' 
butterfly species in the Spring Mountains are declining, as seen with 
Plebejus (= Icaricia) shasta charlestonensis (Mt. Charleston blue 
butterfly). Specifically, the petition states that declines became 
apparent by 2005 and were exacerbated during the 2006, 2007, and 2008 
seasons (Boyd 2009, p. 2). No data were reported for the 2009 season.
    In addition, the petition noted several conservation agreements or 
plans exist to conserve the subspecies; however, few of the obligations 
documented in these agreements and plans have been met. The petitioner 
also states that monitoring requirements outlined in these agreements 
or plans were abandoned after 2003 (Boyd 2009, pp. 1-2).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning All Sites
    Between 1998 and 2002, butterfly monitoring occurred throughout the 
Spring Mountains (Boyd and Austin 1999, pp. 1-77; Boyd et al. 2000a, 
pp. 1-24; Boyd et al. 2000b, pp. 1-8; Boyd and Austin 2001, pp. 1-15; 
Boyd and

[[Page 20618]]

Austin 2002, pp. 1-15; Dewberry et al. 2002, pp. 1-16; Boyd 2004, pp. 
1-10). Butterfly numbers fluctuated between and within sites during 
this time (see Table 2 above). Many unknown elements exist pertaining 
to the petitioner's site visits including: (1) Survey protocol 
standards, (2) number of visits, (3) timing of visits, and (4) weather 
conditions during the visits. Since 2003, inventory efforts primarily 
have occurred where proposed activities may affect the subspecies 
(DataSmiths 2007, pp. 1-31; Forest Service 2007a, pp. 1-9; Forest 
Service 2007b, pp. 1-57; Jones and Stokes 2007a pp. 1-73; Jones and 
Stokes pp. 2007b 1-50; Kingsley 2008, pp. 1-18). Such project-specific 
monitoring assists in determining potential project impacts. Monitoring 
for populations and habitats of Spring Mountains acastus checkerspot 
butterfly has occurred purposefully, but intermittently, with different 
levels of effort, at various locations throughout its range. These 
differences and inconsistencies in monitoring make it difficult to 
determine the cause-and-effect relationships associated with activities 
that may affect the Spring Mountains acastus checkerspot butterfly (see 
Factor E discussion below for information on butterfly population 
trends in general).
    The Spring Mountains acastus checkerspot butterfly is included in a 
1998 Conservation Agreement for the Spring Mountains National 
Recreation Area (Conservation Agreement) to facilitate cooperation 
among the parties (U.S. Forest Service, U.S. Fish and Wildlife Service, 
and State of Nevada Department of Conservation and Natural Resources) 
in providing long-term protection for the rare and sensitive flora and 
fauna of the Spring Mountains (Forest Service 1998). The Conservation 
Agreement describes voluntary conservation actions (described below) 
for the butterfly on lands within the Forest Service's jurisdiction 
(Forest Service 1998, pp. 44-49); these voluntary conservation actions 
were intended to protect the subspecies and its habitat. Those actions 
include research, inventory, and monitoring. The petition states that 
very few of the conservation actions in the Conservation Agreement have 
been completed and that monitoring of sites was abandoned in 2003 (Boyd 
2009, p. 2). The conservation actions outlined in the Conservation 
Agreement were to be carried out within a 5-year period between 1998 
and 2002 (Forest Service 1998, p. 28). Between 1998 and 2002, butterfly 
monitoring occurred throughout the Spring Mountains (Boyd and Austin 
1999; Boyd et al. 2000a; Boyd et al. 2000b; Boyd and Austin 2001; Boyd 
and Austin 2002; Dewberry et al. 2002; Boyd 2004). The frequency, 
intensity, and extent of monitoring have varied since 2003.
    The Spring Mountains acastus checkerspot butterfly is a covered 
species under the Clark County Multiple Species Habitat Conservation 
Plan (MSHCP). The Clark County MSHCP identifies two goals for the 
Spring Mountains acastus checkerspot: (a) ``Maintain stable or 
increasing population numbers and host and larval plant species''; and 
(b) ``No net unmitigated loss of larval host plant or nectar plant 
species habitat'' (RECON 2000a, Table 2.5, pp. 2-154; RECON 2000b, pp. 
B162-B164). The Forest Service is one of several signatories on the 
Implementing Agreement for the Clark County MSHCP because many of the 
activities from the 1998 Conservation Agreement were incorporated into 
the MSHCP. Primarily, activities undertaken by the Forest Service 
focused on conducting surveys and monitoring for butterflies. Although 
the Forest Service, Clark County, and the Service contracted some 
surveys and monitoring (see above), a butterfly monitoring plan was not 
fully implemented. The lack of inventory or monitoring does not 
directly correlate to any threat to the Spring Mountains acastus 
checkerspot butterfly or its habitat. However, monitoring population 
status may assist with identifying potential responses to threats.
    In 2004, the Forest Service and the Service entered into a 
voluntary memorandum of agreement (MOA) to establish an interagency 
commitment to early communication, coordination, and conferencing to 
guide project development on Forest Service lands that provide habitat 
for the Spring Mountains acastus checkerspot butterfly (Forest Service 
and Service 2004, p. 1). This MOA is intended to ensure that forest 
activities are designed to reduce impacts to listed species under 
conservation agreements or habitat conservation plans (Forest Service 
and Service 2004, p. 4).
    In 2007, a survey protocol was prepared to survey or inventory 
butterflies of concern at sites subject to Forest Service management 
(Forest Service et al. 2007, p. 1). The butterfly inventory techniques, 
of assessing habitat and walking survey transects, were utilized to 
maximize the possibility of encountering targeted adult butterflies 
(Forest Service et al. 2007, p. 1). Monitoring of the Spring Mountains 
acastus checkerspot butterfly has occurred where activities may 
potentially affect the subspecies and its habitat (e.g., DataSmiths 
2007; Forest Service 2007a; Forest Service 2007b;Jones and Stokes 
2007a; Jones and Stokes 2007b; Kingsley 2008), but it is unclear which 
conservation actions have taken place since 2003.
Information Provided in the Petition Concerning the Kyle Canyon 
(Middle) Colony Site
    The petition notes that when this site has been surveyed, adults of 
both sexes of the Spring Mountains acastus checkerspot butterfly are 
consistently present, but that the numbers of individuals found are low 
(Boyd 2009, p. 3). The petitioners assert that threats at the Kyle 
Canyon (middle) colony include highway modifications (expansions, 
grading, and wash realignments), power line maintenance, fuels 
reduction or treatment projects, and equestrian and vehicle traffic 
(Boyd 2009, p. 3). The petition also notes (Boyd 2009, p. 3) plans for 
a large Forest Service visitor's complex at the site of a former golf 
course, and construction of a hiking trail. The proposed hiking trail 
was asserted to traverse the length of the breeding site (Boyd 2009, p. 
3).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Kyle Canyon (Middle) Colony Site
    Information in Service files suggests that this colony site is 
small relative to the other colonies, but likely stable (see Table 1 
above). Individuals have been found every season the site is surveyed, 
and the numbers of individuals found during surveys are consistently 
low. The petition states that this population has been declining since 
the late 1990s, but the data we have available indicate that the 
numbers at this site are low every year (see Table 2 above).
    We have no additional recent information in our files concerning 
threats from highway modifications (expansions, grading, and wash 
realignments), power line maintenance, and equestrian and vehicle 
traffic. Our files contain a 1999 report (Boyd and Austin 1999, p. 59) 
that lists a number of habitat-related factors that could adversely 
affect the Spring Mountains acastus checkerspot butterfly in the Kyle 
Canyon area including grading, sod dumping, large vehicle occurrence as 
indicated by tracks, and clearing. Neither the 1999 report nor the 
petition provides any information or supporting references that 
characterize the scope, immediacy, and intensity of any of these 
potential stressors.

[[Page 20619]]

    Our files contain information on both the beneficial and negative 
impacts of recent fuels reduction projects. Fuels reduction projects 
are designed to reduce the volume and cover of woody vegetation. Some 
potential negative impacts of fuels reduction projects include the 
crushing of larvae, reductions in larval host plants or adult nectar 
plants, and reductions in the number of male perching or mate location 
sites. The most recent fuels reduction project is the Spring Mountains 
National Recreation Area Hazardous Fuels Reduction Project (Forest 
Service 2007a, pp. 1-9; Forest Service 2007b, pp. 1-57). Design 
criteria outlined in the environmental assessment for this project 
(Forest Service 2007b, Appendix B Design Criteria W5, W6, W7, and M1) 
were developed to address impacts to the Spring Mountains acastus 
checkerspot and other butterflies included in the Conservation 
Agreement, and provided for surveys of butterflies and habitat, habitat 
mapping, abstaining from any host plant removal in core colonies, 
avoidance of host plants, minimization of disturbance by using manual 
methods, monitoring during implementation, and post-project monitoring 
of butterflies and their habitat. The Forest Service began 
implementation of the Spring Mountains Hazardous Fuels Reduction 
Project in 2008, including employment of associated design criteria and 
conservation measures. A monitoring program is underway to assess the 
impacts and benefits to butterfly host plants.
    The information indicates that fuels treatment projects can have 
short-term, negative impacts to habitat and individuals, or loss of 
viability (Forest Service 2007a, pp. 18, 22-23). Even though the impact 
duration is short-term, given the small documented population at the 
Kyle Canyon (middle) site, any short-term, negative impact could be a 
threat to this colony (see Table 2 above).
    Fuels treatment projects may be beneficial to habitat and 
individuals by reducing the risk of wildfire in the localized areas 
where the Spring Mountains acastus checkerspot butterfly occurs. Over 
the long term, fuels reductions may improve habitat by increasing 
nectar and host plant availability. Studies of treatments in other 
areas of pi[ntilde]yon-juniper showed correlated increases of nectar 
plants, host plants, and butterflies (Koniak 1985, p. 559; Kleintjes et 
al. 2004, pp. 235-236). The one known larval host, green rabbitbrush, 
re-sprouts or invades vigorously after fires or other disturbances 
(Koniak 1985, p. 559). The Spring Mountains acastus checkerspot 
butterfly could benefit from fuels treatment activities after a period 
of time as the treatments improve nectar or host plant availability.
    Information in our files confirms plans for a visitor center and 
associated trail, but does not indicate that these projects will have a 
significant negative impact on the Spring Mountains acastus checkerspot 
butterfly. Design criteria and measures were incorporated into the 
project, specifically into the design of a hiking trail in or along 
Kyle Canyon Wash, to prevent and minimize impacts to the Spring 
Mountains acastus checkerspot butterfly (Forest Service 2009, pp. 4-5). 
These criteria and measures include employing construction techniques 
to avoid or minimize temporary disturbance through known Spring 
Mountains acastus checkerspot butterfly breeding areas, prohibit 
construction of Kyle Canyon Wash Trail and buried utilities from early 
May to mid-July (to avoid the butterfly's flight season), erect 
temporary construction fencing along the proposed construction limits 
of planned improvements prior to any ground-disturbing activities, 
require the contractor to contain all construction activities within 
the approved construction limits, maintain temporary fencing until 
notified by the Contracting Officer, collect native seed from 
appropriate larval host and nectar plants and revegetate temporary 
construction disturbance areas following completion of construction, 
implement construction dust control measures to minimize impacts to 
blooming nectar plant populations, reduce off-trail use in documented 
Spring Mountains acastus checkerspot breeding/mate selection areas, and 
construct a fence/barrier adjacent to the newly constructed trail in 
Kyle Canyon Wash. When the project is implemented in 2011, or later, 
the incorporated design criteria and measures should avoid or limit 
impacts to the Spring Mountains acastus checkerspot butterfly in Kyle 
Canyon Wash. Any impacts to the Spring Mountains acastus checkerspot 
butterfly in Kyle Canyon Wash are anticipated to be minor, and 
negligible to the overall population of the subspecies at this site.
Information Provided in the Petition Concerning the Potosi Mountain/Mt. 
Potosi/Boy Scout Camp Colony Site
    The petition asserts that a 2007 fuels reduction project stacked 
cut waste more than a meter high along and on both sides of the dirt 
road at this site, effectively blocking all male perching/mate locating 
sites (Boyd 2009, p. 3).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Potosi Mountain/Mt. Potosi/Boy Scout Camp 
Colony Site
    We have no information in our files to dispute or support the 
assertion that blocking has occurred or could threaten the Spring 
Mountains acastus checkerspot butterfly at this colony site. We 
interpret the term ``blocked'' to mean obstruction of male perching/
mate locating sites as a result of these areas being covered by debris. 
There is no information in our files to determine if, or to what 
extent, the alleged blocking of male perching sites is still occurring 
at this site. Though the numbers of sites available for perching by 
males may be reduced temporarily if cut waste is piled for later 
treatment (commonly chipping or burning), other sites may be available, 
as the Spring Mountains acastus checkerspot butterfly has been observed 
using multiple perch sites during mate locating (Kingsley 2008, pp. 4, 
7-8).
    As noted above, fuels reduction projects may have a short-term, 
negative impact by reducing the number of male perching/mate locating 
sites. The petition provided no population estimates for this colony, 
nor do we have any information in our files regarding population 
estimates for this colony. However, the petition states that 
individuals of both sexes were found at the site in 2006, but no 
individuals were found during the 2007 flight season (Boyd 2009, p. 3). 
No surveys have been completed since 2007.
Information Provided in the Petition Concerning the Griffith Peak 
Trail/Harris Spring Road/Harris Mountain Road Colony Site
    The petition states that there is no immediate threat to habitat or 
range, as a whole, at this site (Boyd 2009, pp. 3-4).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Griffith Peak Trail/Harris Spring Road/
Harris Mountain Road Colony Site
    We have no additional information on threats to the Spring 
Mountains acastus checkerspot butterfly's habitat or range at this 
site.
Information Provided in the Petition Concerning the Trough Spring 
Colony Site
    The petition asserts that horses and introduced elk are having 
negative effects on the Trough Spring colony site (Boyd 2009, p. 4). 
The petition also indicates that while the site is closed to off-
highway vehicle use, violations are not uncommon (Boyd 2009, p. 4). In

[[Page 20620]]

addition, the petition states that 20 individuals were found when the 
site was surveyed in 2002, 41 individuals were found during surveys in 
2003, but 0 individuals were found during a 2007 visit to the site 
(Boyd 2009, p. 4).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Trough Spring Colony Site
    We have no information in our files to dispute or support the 
assertion that the area is used by horses, elk, and off-highway 
vehicles. However, neither the petition nor any available information 
in our files provides any information or supporting references that 
describe the scope, immediacy, and intensity of any of these potential 
stressors.
    During three site visits in 2002, the highest total number of 
individuals counted was 20. During five site visits in 2003, the 
highest total number of individuals counted was 41 (see Table 2 above). 
While the petition notes a single site visit in 2007 where no 
individuals were found, conducting a single visit during the flight 
period is not in accordance with standard butterfly monitoring 
protocol, and is not considered adequate to gauge abundance or derive 
trends. However, because we have no recent survey data for this site, 
we cannot rule out the possibility that the 2007 survey result of zero 
individuals may indicate a downward trend in numbers at this site.
Summary of Factor A
    Fuels reduction projects, horses and introduced elk, and off-
highway vehicles may negatively affect Spring Mountains acastus 
checkerspot butterfly individuals and habitat. All of these activities 
could negatively alter habitat through one or more of the following 
mechanisms: Crushing larvae, reducing the amounts of larval host 
plants, reducing the amount of adult nectar plants, and reducing the 
amount of male perching/mate location sites. Declines in numbers of 
individuals have been observed at sites where fuels reduction projects 
(Potosi Mountain/Mt. Potosi/Boy Scout Camp Colony Site), horses and 
introduced elk (Trough Spring Colony Site), and off-highway vehicle 
activities (Trough Spring Colony Site) occur. This provides evidence to 
suggest that the Spring Mountains acastus checkerspot butterfly may be 
negatively affected by these activities. In summary, we find that the 
information provided in the petition, as well as other information in 
our files, presents substantial information indicating that the 
petitioned action may be warranted due to the present or threatened 
destruction, modification, or curtailment of the species' habitat or 
range, specifically because of fuels reduction projects, horses and 
introduced elk, and off-highway vehicles.

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

Information Provided in the Petition
    There was no information provided in the petition regarding the 
overutilization for commercial, recreational, scientific, or 
educational purposes being a threat to the Spring Mountains acastus 
checkerspot butterfly.
Evaluation of Information Provided in the Petition and Available in 
Service Files
    Neither the petition nor information in our files provides any 
information pertaining to threats under this factor with regard to the 
Spring Mountains acastus checkerspot butterfly. Therefore, we find that 
the information provided in the petition, as well as other information 
in our files, does not indicate or document that overutilization for 
commercial, recreational, scientific, or educational purposes poses a 
threat to the species. However, we will evaluate all factors, including 
overutilization from commercial, recreational, scientific, or 
educational purposes, when we conduct the status review.

C. Disease or Predation

Information Provided in the Petition
    There was no information provided in the petition regarding disease 
or predation being a threat to the Spring Mountains acastus checkerspot 
butterfly.
Evaluation of Information Provided in the Petition and Available in 
Service Files
    Neither the petition nor information in our files provides any 
information pertaining to disease or predation with regard to the 
Spring Mountains acastus checkerspot butterfly. Therefore, we find that 
the information provided in the petition, as well as other information 
in our files, does not indicate or document that disease or predation 
poses a threat to the species. However, we will evaluate all factors, 
including disease and predation, when we conduct the status review.

D. The Inadequacy of Existing Regulatory Mechanisms

Information Provided in the Petition
    There was no information provided in the petition regarding the 
inadequacy of existing regulatory mechanisms being a threat to the 
Spring Mountains acastus checkerspot butterfly.
Evaluation of Information Provided in the Petition and Available in 
Service Files
    The petition does not provide any information pertaining to the 
inadequacy of existing regulatory mechanisms with regard to the Spring 
Mountains acastus checkerspot butterfly. In addition, the Service files 
do not provide any information pertaining to the inadequacy of existing 
regulatory mechanisms for the Spring Mountains acastus checkerspot 
butterfly. Therefore, we find that the information provided in the 
petition, as well as other information in our files, does not indicate 
or document that the inadequacy of existing regulatory mechanisms poses 
a threat to the species. However, we will evaluate all factors, 
including the inadequacy of existing regulatory mechanisms, when we 
conduct the status review.

E. Other Natural or Manmade Factors Affecting the Subspecies' Continued 
Existence

Information Provided in the Petition Concerning the Kyle Canyon 
(Middle) Colony Site
    The petition (Boyd 2009, p. 3) asserts highway contaminants, road 
salt, equestrian and vehicle traffic, and increasing abundance of 
Medicago sp., a nonnative alfalfa species, are threats to Spring 
Mountains acastus checkerspot butterfly at the Kyle Canyon (middle) 
colony site.
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Kyle Canyon (Middle) Colony Site
    We have no information or supporting references that characterize 
the scope, immediacy, and intensity of any of these potential 
stressors. However, the small documented population at this site may 
increase the vulnerability of the Spring Mountains acastus checkerspot 
butterfly to other potential threats. We will further investigate these 
potential threats as they pertain to the Spring Mountains acastus 
checkerspot butterfly during our status review for this subspecies.

[[Page 20621]]

Information Provided in the Petition Concerning the Potosi Mountain/Mt. 
Potosi/Boy Scout Camp Colony Site
    The petition asserts that a protracted drought is adding to the 
stresses associated with the fuels reduction project at the Potosi 
Mountain/Mt. Potosi/Boy Scout Camp site (Boyd 2009, p. 3).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Potosi Mountain/Mt. Potosi/Boy Scout Camp 
Colony Site
    It has been observed that during drought, butterfly populations may 
be lower (Ehrlich et al. 1980, pp. 101-105; Thomas 1984, p. 344). In 
2006, populations of many butterfly species were low throughout 
southern Nevada, south of the Great Basin, likely as a result of 
drought conditions (Murphy 2006, p. 3). In 2007, other species of 
butterflies in the Spring Mountains experienced population declines, 
and these declines were hypothesized to be a result of drought 
(Datasmiths 2007, p. 22). While Boyd (2008, p. 2) speculated that 
populations of other butterfly species may have declined as a result of 
drought and other factors, population trends of the Spring Mountains 
acastus checkerspot butterfly were not being specifically monitored. 
Though populations may be low during some years as a result of drought, 
checkerspot species (Chlosyne sp.) may survive unfavorable weather 
years by diapausing for 2 or more years (Scott 1986, p. 307). Drought 
may not be a threat, in and of itself, to the Spring Mountains acastus 
checkerspot butterfly. However, drought coupled with other factors, 
such as fuels reduction projects and other manmade stressors, may 
result in the Spring Mountains acastus checkerspot butterfly being more 
susceptible to other threats.
Information Provided in the Petition Concerning the Griffith Peak 
Trail/Harris Spring Road/Harris Mountain Road Colony Site
    The petition asserts that disturbance by vehicle and hiking traffic 
are threats at the Griffith Peak Trail/Harris Spring Road/Harris 
Mountain Road colony site as a result of direct disturbanceS to the 
butterflies by vehicles and hikers (Boyd 2009, pp. 3-4). According to 
the petition, use of the road and trail appears to be increasing, which 
disturbs the butterflies during the flight period. The petition states 
that the numbers of individuals found during surveys at this site have 
continued to decline each year beginning with 104 individuals in 2001, 
50 individuals in 2002, 27 individuals in 2003, and 3 individuals in 
2007 (Boyd 2009, p. 4). This site has not been visited since 2007.
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Griffith Peak Trail/Harris Spring Road/
Harris Mountain Road Colony Site
    We have no information in our files to support or dispute the 
assertion that hikers and vehicular traffic are disturbing Spring 
Mountains acastus checkerspot butterflies at this site. Neither the 
petition nor any available information in our files provides any 
information or supporting references that characterize the scope, 
immediacy, and intensity of any of these potential stressors. Surveys 
found butterfly numbers fluctuated from 19 individuals in 2000, to 104 
individuals in 2001, to 50 individuals in 2002, to 27 individuals in 
2003 (see Table 2 above). However, differences and inconsistencies in 
monitoring make it difficult to interpret survey results. Based on the 
available information, there appears to be a potential population 
decline at the Griffith Peak Trail/Harris Spring Road/Harris Mountain 
Road colony site. The petition states that vehicle and hiking traffic 
that disturb the butterfly during the flight period may be a threat to 
the Spring Mountains acastus checkerspot butterfly.
Information Provided in the Petition Concerning the Trough Spring 
Colony Site
    Even though this site is relatively remote and is closed to 
motorized vehicles, the petition asserts that traffic from off-highway 
vehicle activity does occur, and is a threat at the Trough Spring site 
(Boyd 2009, p. 4). The petition also states that 20 individuals were 
found when the site was surveyed in 2002, and 41 individuals were found 
during surveys in 2003, but 0 individuals were found during a 2007 site 
visit conducted during the appropriate time of year (Boyd 2009, p. 4).
Evaluation of Information Provided in the Petition and Available in 
Service Files Concerning the Trough Spring Colony Site
    We have no information or supporting references that characterize 
the scope, immediacy, and intensity of this potential threat. However, 
based on the available information, there appears to be a potential 
recent population decline at the Trough Spring colony site. The 
petition states that illegal motorized vehicle activity may be a threat 
to the Spring Mountains acastus checkerspot butterfly at this site.
Summary of Factor E
    Based on the available information, there appears to be potential 
population declines at the Griffith Peak Trail/Harris Spring Road/
Harris Mountain Road colony site and the Trough Spring colony sites. 
The petition states that vehicle and hiking traffic that disturb the 
butterfly during the flight period may be a threat to the Spring 
Mountains acastus checkerspot butterfly, and we will further evaluate 
this in our status review. Information provided by the petition and 
available in our files suggests that drought may be a potential added 
stressor to the Spring Mountains acastus checkerspot butterfly at some 
locations where additional threats occur. In summary, we find that the 
information provided in the petition, as well as other information in 
our files, presents substantial information indicating that the 
petitioned action may be warranted due to other natural or manmade 
factors affecting the subspecies' continued existence, specifically 
because of vehicle and hiking traffic and drought.

Finding

    On the basis of our evaluation of the petition under section 
4(b)(3)(A) of the Act, we determine that the petition presents 
substantial scientific or commercial information indicating that 
listing the Spring Mountains acastus checkerspot butterfly may be 
warranted. This finding is based on information provided under Factors 
A and E. We determine that the information provided under Factors B, C, 
and D is not substantial. The available information indicates fuels 
reduction projects may have a negative impact on Spring Mountains 
acastus checkerspot butterfly individuals and habitat. The possible 
declining trends at the Potosi Mountain/Mt. Potosi/Boy Scout Camp 
Colony Site indicate that fuels reduction projects may be a threat to 
the Spring Mountains acastus checkerspot butterfly at this site (Factor 
A). In addition, potential declining population trends at the Griffith 
Peak Trail/Harris Spring Road/Harris Mountain Road colony site and the 
Trough Spring colony site indicate that vehicle and hiking traffic that 
disturb the butterfly flight period may be a threat to the subspecies 
(Factor E). Additionally, drought (Factor E) may be an added stressor 
to the Spring Mountains acastus checkerspot butterfly at some locations 
where additional threats occur.
    Because we have found that the petition presents substantial

[[Page 20622]]

information indicating that listing may be warranted, we are initiating 
a status review to determine whether listing the Spring Mountains 
acastus checkerspot butterfly under the Act is warranted. All relevant 
information pertaining to each of the five factors will be fully 
evaluated in the forthcoming status review.
    The ``substantial information'' standard for a 90-day finding 
differs from the Act's ``best scientific and commercial data'' standard 
that applies to a status review to determine whether a petitioned 
action is warranted. A 90-day finding does not constitute a status 
review under the Act. In a 12-month finding, we will determine whether 
a petitioned action is warranted after we have completed a thorough 
status review of the species, which is conducted following a 
substantial 90-day finding. Because the Act's standards for 90-day and 
12-month findings are different, as described above, a substantial 90-
day finding does not mean that the 12-month finding will result in a 
warranted finding.

References Cited

    A complete list of references cited is available on the Internet at 
http://www.regulations.gov and upon request from the Nevada Fish and 
Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

Authors

    The primary authors of this notice are the staff members of the 
Nevada Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

Authority

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

    Dated: March 29, 2011.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2011-8824 Filed 4-12-11; 8:45 am]
BILLING CODE 4310-55-P