Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List Spring Mountains Acastus Checkerspot Butterfly as an Endangered or Threatened Species, 59357-59371 [2012-23739]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 77, Number 188 (Thursday, September 27, 2012)]
[Proposed Rules]
[Pages 59357-59371]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-23739]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R8-ES-2010-0077; 4500030113]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List Spring Mountains Acastus Checkerspot Butterfly as 
an Endangered or Threatened Species

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the Spring Mountains acastus 
checkerspot butterfly (Chlosyne acastus robusta) as an endangered 
species under the Endangered Species Act of 1973, as amended (Act). 
After review of the best available scientific and commercial 
information, we find that listing the Spring Mountains acastus 
checkerspot butterfly is not warranted at this time. However, we ask 
the public to submit to us any new information that becomes available 
concerning the threats to the Spring Mountains acastus checkerspot 
butterfly or its habitat at any time.

DATES: The finding announced in this document was made on September 27, 
2012.

ADDRESSES: This finding is available on the internet at https://www.regulations.gov at Docket Number FWS-R8-ES-2010-0077. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Nevada Fish and Wildlife Office, 4701 North 
Torrey Pines Drive, Las Vegas, NV 89130. Please submit any new 
information, materials, comments, or questions concerning this finding 
to the above street address.

FOR FURTHER INFORMATION CONTACT: Edward D. Koch, Field Supervisor, 
Nevada Fish and Wildlife Office (see ADDRESSES); by telephone at 775-
861-6300; or by facsimile at 775-861-6301. If you use a 
telecommunications device for the deaf (TDD), please call the Federal 
Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION: 

Background

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

Previous Federal Actions

    On September 18, 2009, we received a petition dated September 16, 
2009, from Bruce M. Boyd requesting that the Spring Mountains acastus 
checkerspot butterfly (Chlosyne acastus robusta) be listed as an 
endangered species under the Act. Included in the petition was 
information regarding the species' taxonomy, historical and current 
distribution, present status, and potential causes of decline. We 
acknowledged the receipt of the petition in a letter to Bruce M. Boyd, 
dated November 24, 2009. In that letter, we responded that we had 
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 
contained substantial information indicating that the action may be 
warranted. On April 13, 2011, we published a 90-day petition finding 
(76 FR 20613) in which we concluded that the petition and information 
in our files provided substantial information indicating that listing 
the Spring Mountains acastus checkerspot butterfly may be warranted, 
and we initiated a status review. This notice constitutes the 12-month 
finding on the September 16, 2009, petition to list the Spring 
Mountains acastus checkerspot butterfly.

[[Page 59358]]

Taxonomy and Subspecies Description

    William Henry Edwards (1874, pp. 16-17) provided the first 
descriptions of the sagebrush checkerspot butterfly (Chlosyne acastus 
(= Melitaea acastus)) from specimens collected during the Hayden 
expedition of 1871, Wheeler expedition of 1872, and by Henry Edwards, 
Esq. (Brown 1966, pp. 402-405). Specimens collected earlier by Edwards 
and named Melitaea sterope (Edwards 1870, pp. 190-191) were considered 
a subspecies of northern checkerspot butterfly (Chlosyne palla), but 
were subsequently considered conspecific with sagebrush checkerspot 
butterflies (Pelham 2008, p. 379). Other synonyms of the genera 
Chlosyne used with the species acastus have included Charidryas and 
Lemonias (Dyar 1903, pp. 17-18; Opler and Warren 2003, pp. 35-36; 
Pelham 2008, pp. 379-380).
    Since Edwards' first descriptions of the species in 1870 and 1874, 
nine subspecies of sagebrush checkerspot butterfly have been named and 
are listed by Pelham in ``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 common names, 
acastus and sagebrush checkerspot butterflies, have been used 
interchangeably in the literature for species and subspecies; however, 
throughout this finding sagebrush checkerspot butterfly will be used to 
reference the species (Chlosyne acastus) and acastus checkerspot 
butterfly will be used to reference the subspecies (C. a. acastus). The 
other subspecies in the 2008 Pelham catalogue include: no common name 
(C. a. arkanyon); Dorothy's checkerspot butterfly (C. a. dorothyi); 
Neumoegen's checkerspot butterfly (C. a. neumoegeni); Spring Mountains 
acastus checkerspot butterfly (C. a. robusta); Sabina checkerspot 
butterfly (C. a. sabina); no common name (C. a. sterope); Death Valley 
checkerspot butterfly (C. a. vallismortis); and no common name (C. a. 
waucoba) (Bauer 1975, pp. 157-158; Garth and Tilden 1986, p. 82; 
Davenport 2004, p. 15; Pelham 2008, pp. 379-380).
    Large expanses of desert geographically separate the Spring 
Mountains acastus checkerspot butterfly from all other sagebrush 
checkerspot butterfly populations and subspecies, with the exception of 
Neumoegen's checkerspot butterflies, which have a range that is 
adjacent to the Spring Mountains acastus checkerspot butterfly (Austin 
1998, p. 577). Biologically, the Spring Mountains acastus checkerspot 
butterfly is largely separated from the Neumoegen's checkerspot 
butterfly by different flight periods with only a brief period of 
potential overlap. Neumoegen's checkerspot butterflies have previously 
been considered a distinct species (Ehrlich and Ehrlich 1961, p. 135; 
dos Passos 1969, p. 118; Bauer 1975, p. 158; Austin and Austin 1980, p. 
40). In addition to a later flight period, Neumoegen's checkerspot 
butterflies use different larval host plants than Spring Mountains 
acastus checkerspot butterflies (Austin and Leary 2008, p. 102). While 
this may currently assist with classifications (Ackery 1988, pp. 95-
203), the use of larval host plants to identify butterflies to the 
species or subspecies level may not be conclusive because host plant 
relationships may be evolutionarily dynamic, meaning that host plant 
use may change during the evolutionary process (Wahlberg 2001, p. 530). 
Details of Spring Mountains acastus checkerspot butterfly's biology and 
life history are provided below.
    Subspecies of adult sagebrush checkerspot butterflies have similar 
morphological characteristics. The wingspan of adult sagebrush 
checkerspot butterfly species may range from 1.2-1.5 inches (in) (3.0-
3.8 centimeters (cm)) (Opler 1999, p. 299). The upperside of the wing 
is a spider-web-like pattern of orange and black (Layberry et al. 1998, 
p. 187). The hindwing underside has bands of mostly creamy white and 
orange-red spots (Layberry et al. 1998, p. 187) with dark margins. The 
forewing underside is primarily orange. In addition, male and female 
sagebrush checkerspot butterflies are similar in appearance (Layberry 
et al. 1998, p. 187). While there are similarities amongst the 
subspecies of sagebrush checkerspot butterflies, there are subtle 
variations, which were described by Austin 1998 (p. 577), that 
distinguish the Spring Mountains acastus checkerspot butterfly from 
other nearby subspecies.
    In his description of the adult Spring Mountains acastus 
checkerspot butterfly, Austin 1998 (p. 577) compares it to the acastus 
checkerspot butterfly, Death Valley checkerspot butterfly, and the 
Neumoegen's checkerspot butterfly. Compared to the acastus checkerspot 
butterfly, the Spring Mountains acastus checkerspot butterfly is 
described as being larger in size, having a more orange than yellow 
aspect, and having broader black marks and less basal black on the 
upperside of the hindwing (Austin 1998, p. 577). The Spring Mountains 
acastus checkerspot butterfly has less contrast than the acastus 
checkerspot butterfly between the darker and paler orange areas on both 
surfaces, especially for females (Austin 1998, p. 577). In addition, 
the Spring Mountains acastus checkerspot butterfly is described as 
having a deeper yellow in the pale areas on the underside of the 
hindwing than the acastus checkerspot butterfly (Austin 1998, p. 577).
    Compared to the Death Valley checkerspot butterfly, the Spring 
Mountains acastus checkerspot butterfly is larger and deeper orange 
with less contrast (Austin 1998, p. 577). The Death Valley checkerspot 
butterfly is yellowish-orange with narrower black markings than the 
Spring Mountains acastus checkerspot butterfly (Austin 1998, p. 577). 
The underside of the Spring Mountains acastus checkerspot butterfly has 
a heavier black pattern towards the outside edge of the wings and has a 
more orange color, which appears more washed out (Austin 1998, p. 577). 
In addition, the lines of checkerspot pattern on the underside near the 
base of the hindwing are thicker in the Spring Mountains acastus 
checkerspot butterfly than the Death Valley checkerspot butterfly 
(Austin 1998, p. 577).
    Compared to the Spring Mountains acastus checkerspot butterfly, the 
Neumoegen's checkerspot butterfly is paler orange with narrower or 
inconspicuous to absent black lines that run across the wing (Austin 
1998, p. 577). In addition the Neumoegen's checkerspot butterfly has 
more brilliant pale white areas on the underside of the hindwing than 
the deeper yellow of the Spring Mountains acastus checkerspot butterfly 
(Austin 1998, p. 577).
    The similarities in appearance among and between species of 
checkerspot butterflies (for example, Chlosyne acastus, C. gabbii, C. 
palla, and C. whitneyi) have led to challenges in distinguishing 
species and subspecies (Higgins 1960, pp. 395, 421, 426; Ehrlich and 
Ehrlich 1961, p. 132; Ferris and Brown 1981, pp. 325-326; Scott 1986, 
pp. 305-307). In addition, there have been specific conflicting 
taxonomic views about the sagebrush checkerspot butterflies in the 
Spring Mountains (Austin and Austin 1980, p. 40; Austin 1981, p. 71; 
Austin 1985, p. 108; Bauer 1975, pp. 155-156; Britten et al. 1993, p. 
133; Emmel et al. 1998, pp. 141-142; Higgins 1960, p. 428; Kons 2000, 
p. 532).
    Austin recognized the Spring Mountains acastus checkerspot 
butterfly (Chlosyne acastus robusta) as a distinct subspecies based on 
differences in size and wing color characteristics (Austin 1998, pp. 
576-577). Austin (1998, p. 576) notes that distinct phenotypes of C. 
acastus are present in certain montane

[[Page 59359]]

populations, which provide the context for the designation of 
subspecies. Another study used phylogenetic, morphological, 
distributional, and biological information to taxonomically evaluate 
the Spring Mountains acastus checkerspot butterfly (Kons 2000, p. 2). 
Kons (2000, pp. 549-555) did not recognize populations of sagebrush 
checkerspot butterflies in the Spring Mountains as a subspecies due to 
the similarity of the characters he examined and compared between 
sagebrush checkerspot butterflies and other checkerspot butterflies. 
However, there are differences in the geographic distribution or 
continuity and biological characteristics between the sagebrush 
checkerspot butterfly population in the Spring Mountains and 
populations elsewhere that support Austin's (1998, pp. 576-577) 
designation of the Spring Mountains acastus checkerspot butterfly as a 
subspecies.
    Even though there is conflicting information on the taxonomic 
designation of the Spring Mountains acastus checkerspot butterfly, 
Austin (1998, p. 576) is cited as the reference for the subspecies 
level taxonomic designation for the Spring Mountains acastus 
checkerspot butterfly in the Integrated Taxonomic Information System 
(ITIS). 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. ITIS recognizes the 
Spring Mountains acastus checkerspot butterfly as a valid subspecies 
(Retrieved June 18, 2012, from the Integrated Taxonomic Information 
System on-line database, https://www.itis.gov). Based upon the best 
available information, populations of sagebrush checkerspot butterflies 
in the Spring Mountains are considered a valid subspecies and are, 
thus, a valid taxonomic entity for consideration for listing under the 
Act.

Distribution

    The Spring Mountains acastus checkerspot butterfly is known only 
from the Spring Mountains in Clark and Nye Counties, Nevada (Austin 
1998, p. 577), at elevations ranging from minimums near 1,800 meters 
(m) (5,900 feet (ft)) to maximums of 2,700 m (8,900 ft) (Weiss et al. 
1997, p. 17). The majority of observations and habitat for the Spring 
Mountains acastus checkerspot butterfly occur within the Spring 
Mountains National Recreation Area (SMNRA), which is managed by the 
U.S. Department of Agriculture's Forest Service (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 was documented on lands managed by the 
U.S. Department of the Interior, Bureau of Land Management.
    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 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 and Austin 1999, pp. 9, 20-21; Boyd and Austin 2002, pp. 5, 
13; Boyd 2004, pp. 2-3). 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 they represent more than one incidental observation or sighting. 
Researchers define 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). Currently, only four colonies are known to exist. 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. Observations at incidental sighting areas, and the 
potential for 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). 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 (Table 
1).

   Table 1--Areas Where Spring Mountains Acastus Checkerspot Butterfly
                    Observations Have Been Documented
                   [Areas ordered from north to south]
------------------------------------------------------------------------
            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 and picnic area.............  1965.
Deer Creek Road (Telephone Canyon side)  1981 or 1987.
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 *.
------------------------------------------------------------------------
* Colony.
Sources: Weiss et al. 1995, pp. 4, 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.

Status and Trends

    Weiss et al. (1997, p. 2) indicated that butterfly populations are 
highly dynamic, and butterfly distributions can be highly variable from 
year to year. 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). Sagebrush checkerspot butterfly populations may undergo 
extreme fluctuations as a result of rainfall, parasitism, and other 
factors (Stout 2011, https://www.raisingbutterflies.org). Some 
subspecies, such as the Spring Mountains acastus checkerspot butterfly, 
may exist as a metapopulation (``local populations which interact via 
individuals moving among populations'') (Hanski and Gilpin 1991, p. 7) 
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).
    Determining the status of adults at a colony requires multiple 
visits during appropriate flight conditions and frequently enough to 
intercept a potentially short flight period. For example, in 1977, 
Austin and Austin (1980, p. 40) reported visits to the same area of 
Kyle Canyon in which the Spring Mountains acastus checkerspot butterfly

[[Page 59360]]

was observed on 2, 5, and 7 July, but not on 17 or 30 June and 15 July. 
Thus, this flight period may have been less than 2 weeks. In contrast, 
they reported that, in 1965, the flight period lasted over a 5-week 
period. While these observations may indicate a variable flight period, 
it is also possible that the perceived flight period may vary as a 
result of a dynamic interrelationship between search effort and 
abundance. In addition, assessments of population status and trends 
based on counts of particular life stages may be complicated by 
irregular life-history phenomena, such as an extended diapause (a 
period of dormancy, commonly induced by seasonal change in photoperiod 
(day length) or temperature) (Sands and New 2008, pp. 81-85). 
Unnecessary conservation concerns may arise as a result of irregular 
diapause that results in perceived changes in abundance (Sands and New 
2008, pp. 81-85).
    The largest known colony of Spring Mountains acastus checkerspot 
butterfly occurs at Griffith Peak Trail/Harris Spring Road/Harris 
Mountain Road. This 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, because there had been no 
sightings 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. 2000, p. 
4).
    DataSmiths (2007, p. 17) concluded that absence of adults at a site 
does not necessarily equate to ephemeral occupation or extirpation. 
Observations of the Spring Mountains acastus checkerspot butterfly 
illustrate this point. Boyd et al. (2000, p. 4) searched 17 areas (8 
historical and 9 potential sites) for the Spring Mountains acastus 
checkerspot butterfly in 1999. During the 1999 surveys, Spring 
Mountains acastus checkerspot butterflies were observed at five of the 
eight historical sites (including Kyle Canyon (middle) Colony Site), 
with two of these described as potential new colonies (Griffith Peak 
Trail/Harris Spring Road/Harris Mountain Road and Potosi Mountain/Mt. 
Potosi/Boy Scout Camp). During 2003 surveys, the Spring Mountains 
acastus checkerspot butterfly was observed again in the Willow Spring/
Willow Creek area (Boyd 2004, pp. 2-3) where it had not been seen 
during surveys in 1999 (Boyd and Austin 1999, Table 7, p. 98). 
Similarly, in 2003, the Spring Mountains acastus checkerspot butterfly 
was observed in the McFarland Spring/Whisky Spring/Camp Bonanza area 
(Boyd 2004, p. 2), even though it had not been observed there during 
previous surveys in 1998 (Boyd and Austin 1999, Table 12). These 
examples demonstrate that a lack of observations at a site does not 
necessarily mean that a site is extirpated because adult surveys will 
not detect diapausing 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 also is seen in the fluctuation in 
numbers of Spring Mountains acastus checkerspot butterflies observed 
during repeat surveys at the same locations (Table 2). Surveys from 
2000 and 2001 at the Griffith Peak Trail/Harris Spring Road/Harris 
Mountain Road site found 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 Bruce Boyd regarding observations that year, 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, as well as 
at Potosi Mountain/Mt. Potosi/Boy Scout Camp (Boyd 2006, pers. comm.). 
At locations where the butterfly was observed in 2006, Boyd stated that 
it appeared to be in ``appropriate'' numbers (Boyd 2006, pers. comm.). 
These observations support the conclusions of Weiss et al. (1997, p. 2) 
of highly dynamic butterfly populations where sightings may occur 
periodically throughout a species' range, and populations at colony 
sites may fluctuate.

Table 2--Summary of Monitoring Results of Spring Mountains Acastus Checkerspot Butterfly at Three Colony Sites From 1998 Through 2011 Using Standardized
                                                                     Survey Methods
--------------------------------------------------------------------------------------------------------------------------------------------------------
                         Year                            1998     1999     2000     2001     2002     2003     2006     2007     2008     2010     2011
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Kyle Canyon (middle)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Highest /day................................     4-10        5        6        8        6        7        4        1        4  .......        1
 Visits.....................................       16       11        9        6        4        4        1        6        8  .......        6
Peak date(s).........................................       NR     6/19   6/15 &     6/18     6/24     6/10     6/21   6/13 &     6/24  .......     6/13
                                                                            6/30                                         6/21
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Griffith Peak Trail/Harris Spring Road/Harris Mountain Road
--------------------------------------------------------------------------------------------------------------------------------------------------------
Highest /day................................  .......  .......       19      104       50       27  .......  .......  .......       2*        5
 Visits.....................................  .......  .......        9        5        5        4  .......  .......  .......  .......        3
Peak date............................................  .......  .......     6/11     6/18     6/20     6/29  .......  .......  .......  .......   6/27 &
                                                                                                                                                    7/11
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Trough Spring
--------------------------------------------------------------------------------------------------------------------------------------------------------
Highest /day................................  .......  .......  .......  .......       20       41  .......  .......  .......  .......        1
 Visits.....................................  .......  .......  .......  .......        3        5  .......  .......  .......  .......        3
Peak date............................................  .......  .......  .......  .......     6/18      6/1  .......  .......  .......  .......     6/10
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sources: (Boyd and Austin 1999, Table 8; Boyd 2004, p. 8; Jones and Stokes 2007a, p. 4; Jones and Stokes 2007b, p. 3; Kingsley 2008, p. 3, Service
  2011a, pp. 1-3, Thompson et al. 2012, Table 2).
NR = not reported.
* = did not use a standardized survey method.


[[Page 59361]]

    Surveys were conducted in 2010 and 2011 for adult Spring Mountains 
acastus checkerspot butterflies using both standardized and non-
standardized methods. In 2010, at the Griffith Peak Trail/Harris Spring 
Road/Harris Mountain Road colony site, there were a total of four 
butterflies observed during the season (two by Pinyon 2011, p. 19; and 
two by Service 2011a, pp. 1-3), and the highest number of butterflies 
observed on a single day was two (Service 2011a, pp. 1-3). Numbers 
appeared to increase in 2011 at this colony site with a total of 86 
reported observations (59 by Pinyon 2011, p. 19; 4 by Service 2011a, 
pp. 1-3; 23 by Thompson et al. 2012, Table 2), and the highest number 
of butterflies observed on a single day was 13 (Pinyon 2011, p. 19). 
The 13 individuals observed by Pinyon in 2011 were not observed using a 
standardized method similar to Pollard and Yates (1993 cited in Boyd 
and Austin 1999, p. 33) and described by Boyd and Austin (1999, p. 33), 
and are, therefore, not reported in Table 2. Results of the 
standardized surveys performed by Thompson et al. (2012, Table 2) at 
the other colony sites are shown in Table 2. Surveys for Spring 
Mountains acastus checkerspot butterfly were planned for 2012; however 
those data are not yet available.

Habitat

    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 pi[ntilde]yon-juniper (Pinus monophylla-Juniperus 
osteosperma) communities at 1,250-2,500 m (4,100-8,200 ft) and the 
lower elevation white fir-ponderosa pine (Abies concolor-Pinus 
ponderosa var. scopulorum) 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).

Biology

Adults
    The flight season of the Spring Mountains acastus checkerspot 
butterfly is between mid-May and mid-July (Austin and Austin 1980 p. 
40; Weiss et al. 1997, pp. 6, 37; Austin 1998, 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 the closely 
related northern checkerspot butterfly could move as far as 1.6 km (1 
mi). During the flight season, Spring Mountains acastus checkerspot 
butterfly 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), Ceanothus sp. (ceanothus), C. 
greggii (Mojave ceanothus), Melilotus sp. (clover), Penstemon palmeri 
(Palmer penstemon), and Apocynum sp. (dogbane) (Austin and Austin 1980, 
p. 40; Weiss et al. 1995, p. 9; Boyd et al. 2000, p. 6; Jones & Stokes 
2007a, p. 4; Thompson et al. 2012, p. 22).
    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). 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). 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, the males behave territorially. They remain in the same area and 
pursue any other butterflies or insects that come within a zone of a 
few square meters around the male, continuing 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). Mating has 
been observed to last 40 minutes (Boyd 2004, p. 3). Sagebrush 
checkerspot butterflies have a high mating success, as indicated by a 
high percentage (>95) of females with spermatophores (a sac containing 
sperm) (Shields 1967, pp. 90, 123; Rhainds 2010, pp. 212-213). 
Approximately 10 days after mating, the female lays her eggs (Nunnallee 
2011, p. 6).
Eggs
    Clusters of sagebrush checkerspot butterfly eggs are laid on the 
underside of host leaves and sometimes on flower buds (Scott 1986, p. 
307; Stout 2011, https://www.raisingbutterflies.org). Sagebrush 
checkerspot butterflies may lay 100 to 150 eggs in a cluster (Nunnallee 
2011, p. 6). It may be advantageous for female butterflies to lay eggs 
in clusters to reduce exposure to predation or if host plants are rare 
or dispersed (Stamp 1980, p. 376). Eggs hatch after 6 days (Nunnallee 
2011, p. 6), and the young larvae are gregarious on leaves or flowers 
(Scott 1986, p. 307; Nunnallee 2011, p. 6).
Larvae
    Gregarious pre-diapause larvae of sagebrush checkerspot butterflies 
form silk webbing where they feed together on the larval host plant 
(Nunnallee 2011, p. 6; Opler et al. 2011, https://www.butterfliesandmoths.org; Stout 2011, https://www.raisingbutterflies.org). It is hypothesized that gregarious larvae 
may reduce rates of parasitism on the larvae because of collective 
defenses and may also facilitate feeding on larval host plants, 
particularly for early larvae, by enhancing the ability of larvae to 
overcome plant defenses (Chew and Robbins 1984, p. 75). Chrysothamnus 
viscidiflorus has been documented as a larval host plant (Boyd and 
Austin 2002, p. 2; Austin and Leary 2008, p. 99), is a widely 
distributed shrub in Western North America (Anderson 1986a, b as cited 
in McArthur and Stevens 2004, p. 531; Stubbendieck 2003, p. 248), and 
has a range that coincides with many of the ranges shown for sagebrush 
checkerspot butterflies (Opler 1999, p. 199; Opler et al. 2011, https://www.butterfliesandmoths.org). Common names used interchangeably for 
subspecies of C. viscidiflorus have included Douglas rabbitbrush, 
chamisa, green rabbitbrush, low rabbitbrush, yellow rabbitbrush, viscid 
rabbitbrush, sticky-leaved rabbitbrush, downy rabbitbrush, and narrow-
leaved rabbitbrush (Stubbendieck et al. 2003, p. 249; McArthur and 
Stevens 2004, p. 532; 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 (known as viscid 
rabbitbrush, sticky-leaved rabbitbrush, and narrow-leaved rabbitbrush) 
(Niles and Leary 2007, p. 19). A common name for Chrysothamnus 
viscidiflorus viscidiflorus has not been accepted (Young and Evans 
1974, p. 469).
    In the Spring Mountains, Niles and Leary (2007, p. 9) quantified 
the abundance of the various subspecies of Chrysothamnus viscidiflorus 
as rare, occasional, common, and abundant. Chrysothamnus viscidiflorus 
ssp. lanceolatus is occasional to common on slopes, ridges, and in 
washes (Niles and

[[Page 59362]]

Leary 2007, p. 19). Chrysothamnus viscidiflorus ssp. puberulus (= var. 
puberulus) is occasional to rocky washes and on slopes (Niles and Leary 
2007, p. 19). Of butterfly host plants described by Weiss et al. (1997, 
Figure 4), Chrysothamnus viscidiflorus is present in areas with low 
tree canopy cover (mean of 17 percent). Chrysothamnus viscidiflorus 
ssp. viscidiflorus (= var. viscidiflorus) is occasional to sandy-
gravelly washes (Niles and Leary 2007, p. 19). Chrysothamnus 
viscidiflorus has many erect stems that are 1 to 3.5 ft (0.3 to 1.1 m) 
tall, growing from a base (McArthur and Stevens 2004, p. 531). In the 
Spring Mountains, C. viscidiflorus has been categorized as widespread, 
with a large population, and is considered very robust to human 
disturbance (Nachlinger and Reese 1996, pp. 66, 70). More recent 
information indicates that the larval host plant is widely distributed, 
but locally uncommon, within the Spring Mountains (D. Thompson 2012, 
pers. comm.). It is unknown whether or not habitat is a limiting factor 
for the subspecies.
    It is unknown which of these subspecies of Chrysothamnus 
viscidiflorus are used as a larval host plant by the Spring Mountains 
acastus checkerspot butterfly; however, in maps prepared by Jones and 
Stokes (2007b, Figure 5a), Spring Mountains acastus checkerspot 
butterfly observations appeared to be more closely associated with C. 
v. ssp. viscidiflorus than C. v. ssp. puberulus. Warren (2005, p. 232) 
reported that all sagebrush checkerspot butterfly subspecies in Oregon 
use C. v. ssp. viscidiflorus as a host plant, but that other subspecies 
of C. viscidiflorus may be used as well. C. viscidiflorus is the most 
commonly reported species of larval host plant for sagebrush 
checkerspot butterfly subspecies, but other plant species have been 
reported (Service 2011b, p. 4).
    While not documented as a larval host plant for the Spring 
Mountains acastus checkerspot butterfly, Machaeranthera canescens 
occurs in similar habitats (Niles and Leary 2007, p. 20) used by the 
Spring Mountains acastus checkerspot butterfly. Locations with reported 
occurrences of M. canescens in the Kyle Canyon area (Jones and Stokes 
2007b, Figure 13) are near Spring Mountains acastus checkerspot 
butterfly observation areas (Jones and Stokes 2007b, Figure 5a). 
Further study using appropriate methods (Shields et al. 1969, p. 24) 
will be required to determine if Spring Mountains acastus checkerspot 
butterfly uses other larval host plants.
    Ericameria nauseosa (= Chrysothamnus nauseosus; rubber rabbitbrush) 
also has been suspected of being a larval host plant of the Spring 
Mountains acastus checkerspot butterfly (Weiss et al. 1997, p. 6). Boyd 
and Austin (1999, pp. 20-21) unsuccessfully attempted to feed E. 
nauseosa to Spring Mountains acastus checkerspot butterfly larvae, and 
reported that their results were inconclusive. Early inferences that E. 
nauseosa may be the larval host plant for the Spring Mountains acastus 
checkerspot butterfly may be attributed to early uncertainty about its 
taxonomy and its close resemblance to the northern checkerspot 
butterfly, which has been documented to use E. nauseosa and C. 
viscidiflorus as larval host plants (Scott 1986, p. 306; Austin and 
Leary 2008, p. 102), and the interchangeable use of the generic common 
name rabbitbrush when referring to rubber or green rabbitbrush. The 
best available scientific and commercial information does not indicate 
there is any use of E. nauseosa by sagebrush checkerspot butterflies 
(Service 2011b, p. 4).
    After feeding on the larval host plant during favorable conditions, 
larvae enter diapause, which allows them to survive through the winter, 
and which is likely a result of decreasing temperature and photoperiod 
(Scott 1979, p. 172). Spring Mountains acastus checkerspot butterfly 
larvae diapause under rocks as half-grown larvae during the winter 
(Scott 1979, pp. 172, 191; Scott 1986, pp. 27, 307; Opler et al. 2011, 
https://www.butterfliesandmoths.org). During times of unfavorable 
weather, sagebrush checkerspot butterflies may diapause for many months 
or years (Scott 1986, p. 307; Opler et al. 2011, https://www.butterfliesandmoths.org).
    After winter, post-diapause larvae of other subspecies have been 
reported to be solitary (Nunnallee 2011, p. 6); however, Spring 
Mountains acastus checkerspot butterfly larvae of different instars 
(larval stages of growth between molts of the exoskeleton (Scott 1986, 
p. 21)) have been observed together in the Spring Mountains (Boyd 2004, 
p. 3). When disturbed, larvae will release and fall to the understory, 
where they roll into tight balls and are difficult to find (Wolfe 2004, 
p. 13). Stamp (1984, p. 6) hypothesized that thrashing by checkerspot 
butterflies after disturbance may be an adaptation to prevent 
parasitization by wasps or flies. There are no known reports of 
parasites or disease in populations of Spring Mountains acastus 
checkerspot butterflies, likely because of limited numbers and past 
research emphasis on adults, and because it is difficult to detect 
parasites or disease in checkerspot and other butterflies. Parasites 
documented to infect Neumoegen's checkerspot butterfly include the 
Siphosturmia confusa fly (Stireman and Singer 2003, p. 630) and 
braconid wasp Cotesia (= Apanteles) koebelei (Krombein et al. 1979, p. 
249). It has been reported that for the subspecies acastus checkerspot 
butterfly, populations fluctuate as a result of parasitism (Stout 2011, 
https://www.raisingbutterflies.org). In fact, larval mortality in many 
species of butterflies occurs as a result of predation (including 
parasitism) and starvation (Haukioja 1993, as cited in Kuussaari et al. 
2004, p. 148).
    When enough suitable food is present, and after reaching an 
adequate size, larvae find a pupation site where they attach themselves 
to a silk mat (Scott 1986, p. 13) on a leaf or twig (Stout 2011, https://www.raisingbutterflies.org). In 2002, one of four larvae removed from 
the population at the Griffith Peak Trail colony site successfully 
pupated in 11 days (Boyd 2004, p. 3), while other subspecies are 
reported to pupate in 18 days (Nunnallee 2011, p. 6). After pupation, 
adult butterflies emerge to feed and seek mates.

Summary of Information Pertaining to the Five Factors

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
(50 CFR part 424) set forth procedures for adding species to, removing 
species from, or reclassifying species on the Federal Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be endangered or threatened 
based on any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this finding, information pertaining to the Spring 
Mountains acastus checkerspot butterfly in relation to the five factors 
provided in section 4(a)(1) of the Act is discussed below. In 
considering what factors might constitute threats to a species, we must 
look beyond the exposure of the species to a particular factor to 
evaluate whether the species may respond to that factor in a way that 
causes actual impacts to the species. If there is exposure to a

[[Page 59363]]

factor and the species responds negatively, the factor may be a threat 
and, during the status review, we attempt to determine how significant 
a threat it is. The threat is significant if it drives, or contributes 
to, the risk of extinction of the species such that the species 
warrants listing as endangered or threatened as those terms are defined 
in the Act. However, the identification of factors that could impact a 
species negatively may not be sufficient to compel a finding that the 
species warrants listing. The information must include evidence 
sufficient to suggest that these factors are operative threats that act 
on the species to the point that the species may meet the definition of 
an endangered or threatened species under the Act.
    In making our 12-month finding on the petition we considered and 
evaluated the best available scientific and commercial information.

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

All Sites
Fire Suppression
    The Spring Mountains acastus checkerspot butterfly may be 
negatively affected by fire suppression as inferred by its proximity to 
areas with fire disturbance (Boyd and Austin 2002, p. 5; Boyd 2004, p. 
3-4). It has been speculated that effects to the Spring Mountains 
acastus checkerspot butterfly may occur as a result of inhibited 
dispersal (Boyd 2004, p. 3-4). One mechanism for the inhibited 
dispersal could be a decrease in larval host plants across the 
landscape caused by fire suppression. Chrysothamnus viscidiflorus 
increases vigorously and rapidly at disturbed sites (Nachlinger and 
Reese 1996, p. 32; McArthur and Stevens 2004, p. 532). After a 
disturbance, such as a fire, C. viscidiflorus may dominate the habitat 
for a long period of time (Young and Evans 1974, p. 469).
    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 that 
are intolerant of fire) (Nachlinger and Reese 1996, p. 37; Amell 2006, 
pp. 6-9; Boyd and Murphy 2008, pp. 22-28; Denton et al. 2008, p. 21, 
Abella et al. 2011, pp.10, 12). Overall, we have limited information 
about how the frequency, size, or severity of fire has changed through 
time. However, the available evidence does not suggest that fire 
suppression has reduced the amount of habitat for the species, is 
likely to do so in the future, or that habitat is a limiting factor for 
the Spring Mountains acastus checkerspot butterfly. Therefore, based on 
the currently available information fire suppression is not currently a 
threat to the subspecies, nor does it indicate that it is likely to 
become so in the future.
    Our review of the best available information indicates that habitat 
modification or destruction associated with fire suppression is not a 
threat to the subspecies, nor does the available information indicate 
that it is likely to become so in the future. In addition, we discuss 
the habitat threats at individual colony sites below.
Griffith Peak Trail/Harris Spring Road/Harris Mountain Road Colony Site
    Aside from the limited information about the effects of fire 
suppression on the Spring Mountains acastus checkerspot butterfly 
rangewide, there is no information available to indicate that habitat 
modification or destruction is a threat to the Griffith Peak Trail/
Harris Spring Road/Harris Mountain Road colony, nor does the available 
information indicate that it is likely to become so in the future.
Kyle Canyon (Middle) Colony Site
Highway Modifications and Power Line Maintenance
    Highway modifications and power line maintenance activities may 
have affected the Spring Mountains acastus checkerspot butterfly in 
areas near the Kyle Canyon (middle) colony site. Highway modifications 
and power line maintenance (grading, sod dumping, large vehicle 
occurrence (as indicated by tracks), and clearing) were observed in 
1998 in the Kyle Canyon area (Boyd and Austin 1999, p. 59), and in 
2006, historical grading, repairing and roadway replacement, and 
illegal dumping also were observed near the Kyle Canyon (middle) colony 
site (Jones and Stokes 2007a, Appendix B). However, these reports do 
not provide information or references that characterize the scope, 
immediacy, and intensity of any of these potential stressors (processes 
or events with negative impacts). While the reports indicate that these 
activities took place in the same area where Spring Mountains acastus 
checkerspot butterfly occurs, there is no available information 
indicating the level of exposure, such as whether larval and nectar 
plants were impacted. The site was inventoried 16 times in 1998, and, 
based on the descriptions provided in the report (Boyd and Austin 1999, 
p. 10) and the absence of any further disturbance documented in 
subsequent surveys (11 visits in 1999, 9 visits in 2000, 7 visits in 
2001, 6 in 2002, and 5 in 2003) (Boyd et al. 2000, pp. 1-36; Boyd and 
Austin 2001, pp. 1-38; Boyd and Austin 2002, pp. 1-30; Boyd 2004, pp. 
1-11), it appears that these activities may be localized and 
infrequent. In addition, an increase in the number of individuals 
observed from 1999 to 2001 at the Kyle Canyon (middle) colony site 
(Table 2) after the highway modifications and power line maintenance 
suggests that these activities did not cause sufficient impacts to 
cause a decline at this colony site. No information is available 
regarding highway modifications and power line maintenance at the Kyle 
Canyon (middle) Colony Site after 2006.
    Highway modifications and power line maintenance activities have 
occurred historically in localized areas. Although we are not aware of 
any further highway modification projects, we understand that 
maintenance activities can take place in the future, know of no planned 
specific action. The information suggests that currently the intensity 
of this stressor is low and the exposure to the Spring Mountains 
acastus checkerspot butterfly is insignificant because these activities 
occur infrequently in small areas within the butterfly's range. 
Therefore, we have determined that highway modifications and power line 
maintenance are not threats to the Spring Mountains acastus checkerspot 
butterfly now, nor does the available information indicate that they 
are likely to become so in the future.
Fuel Treatments
    Fuel reduction projects may affect the Spring Mountains acastus 
checkerspot butterfly negatively or beneficially. The effects of fuel 
reduction treatments on butterflies depend upon the timing (Pilliod et 
al. 2006, p. 23). Fuel reduction projects could affect the Spring 
Mountains acastus checkerspot butterfly negatively by reducing the 
quantity or quality of habitat and affecting survival or fecundity. On 
the other hand, fuel reduction projects could beneficially affect the 
Spring Mountains acastus checkerspot butterfly by creating conditions 
that favor nectar and larval host plants (Weiss et al. 1997, p. 27). As 
mentioned above, Chrysothamnus viscidiflorus increases vigorously and 
rapidly at disturbed sites (McArthur and Stevens 2004, p. 532) and may 
dominate the habitat for a long period of time following disturbance 
(Young and Evans 1974, p. 469).
    The U.S. Forest Service implemented the Spring Mountains Hazardous 
Fuels Reduction Project in the Spring

[[Page 59364]]

Mountains between 2008 and 2011 (Lillis 2010). It was designed to 
reduce the volume and cover of woody vegetation to lower the wildfire 
risk to life and property in the SMNRA wildland-urban interface (Forest 
Service 2007a, pp. 1-18; Forest Service 2007b, pp. 1-57). Design 
criteria were developed to reduce or avoid potential resource 
conflicts, including those associated with the Spring Mountains acastus 
checkerspot butterfly (Forest Service 2007a, p. 4).
    In areas where the Spring Mountains Hazardous Fuels Reduction 
Project coincides with the Spring Mountains acastus checkerspot 
butterfly, the likelihood of direct mortality to the butterfly or 
impacts to its habitat were minimized by implementing the design 
criteria in the project's environmental assessment (Forest Service 
2007b, Appendix B, Design Criteria B1, B6, W5, W6, W7, W11, M1). The 
design criteria provided for surveys of butterflies and habitat, 
habitat mapping, restrictions on host plant removal in core colonies, 
avoidance of host plants, minimization of disturbance by using manual 
methods, weed prevention, education of implementation crews, monitoring 
during implementation, and post-project monitoring of butterflies and 
their habitat. The scope or geographic extent of the Spring Mountains 
Hazardous Fuels Reduction Project is localized because it occurs along 
the wildland-urban interface in one colony site area, Kyle Canyon 
(middle). The project's initial entry has already occurred, but re-
treating of shrubs may occur every 5 to 10 years after the initial 
treatment (Forest Service 2007a, p. 3).
    The level of exposure to the Spring Mountains acastus checkerspot 
butterfly's eggs and larvae from the Spring Mountains Hazardous Fuels 
Reduction Project is low to insignificant because of the project design 
criteria and the short time required for eggs to hatch. Exposure of 
active larvae to impacts from fuel reduction projects would be small to 
insignificant when design criteria are planned and implemented, such as 
avoiding larval host plants and ensuring that the method (for example, 
manual versus mechanical) and timing (periods of larval inactivity) of 
treatment result in larvae having a lower likelihood of exposure. 
Impacts to Spring Mountains acastus checkerspot butterfly pupae are 
likely insignificant because they affix to the underside of leaves for 
a short period in this stage, and are provided some protection by their 
larval host plant. Finally, Spring Mountains acastus checkerspot 
butterfly adults are mobile and may escape threats from fuels reduction 
projects. Effects on breeding adult Spring Mountains acastus 
checkerspot butterflies are likely insignificant because a short time 
is required for successful copulation and the duration of fuel 
treatment activities is likely brief. The Forest Service avoids 
treatment of vegetation along dry washes (Forest Service 2007a, W8), 
which also reduces the likelihood of exposure and impacts to breeding 
Spring Mountains acastus checkerspot butterflies.
    Although the Spring Mountains Hazardous Fuels Reduction Project may 
result in short-term negative impacts to the Spring Mountains acastus 
checkerspot butterfly, the best available information does not indicate 
that this project has affected the Spring Mountains acastus checkerspot 
butterfly negatively at the population level now, nor is it likely to 
in the future.
Middle Kyle Complex Project
    The Forest Service purchased a golf course property in 2004 that 
will be used for the Middle Kyle Complex Project (Forest Service 2009, 
pp. 2-4). The project includes construction of a visitor center and 
associated trail, and design criteria are in place to prevent and 
minimize impacts to the Spring Mountains acastus checkerspot butterfly 
(Forest Service 2009, pp. 4-5). This design includes criteria and 
measures that will avoid and minimize temporary construction 
disturbance to known Spring Mountains acastus checkerspot butterfly 
breeding areas. The design criteria include the following: Prohibit 
construction of Kyle Canyon Wash Trail and bury utilities from early 
May to mid-July (to avoid the butterfly's flight season); erect 
temporary construction fencing along the proposed construction limits 
prior to any ground-disturbing activities; contain all 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; revegetate temporary 
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 butterfly breeding and mate selection 
areas; and construct a fence or barrier adjacent to the newly 
constructed trail in Kyle Canyon Wash. When the project is implemented, 
in 2012 or later, the design criteria and measures should result in 
minimizing impacts to the Spring Mountains acastus checkerspot 
butterfly and its habitat in Kyle Canyon Wash. Any negative impacts 
from the project are anticipated to be minor and have negligible 
impacts to the overall population of the subspecies and habitat at this 
site.
    The Middle Kyle Complex Project will occur in a localized area, 
and, because of the design criteria, including avoidance of larval host 
plants, the project will result in low response, low intensity, and 
ultimately insignificant exposure of Spring Mountains acastus 
checkerspot butterflies to impacts. Therefore, we have determined that 
the Middle Kyle Complex Project is not a threat to the Spring Mountains 
acastus checkerspot butterfly now, nor does the available information 
indicate that it is likely to become one in the future.
Potosi Mountain/Mt. Potosi/Boy Scout Camp Colony Site
Fuel Treatments
    The Potosi Mountain/Mt. Potosi/Boy Scout Camp colony site is 
located at the Boy Scouts of America Kimball Scout Reservation, north 
of Potosi Mountain. A fuels reduction project, funded through a grant 
from the Nevada Division of Forestry, was implemented in April 2007 
(Otero 2007, p. 6). The 2007 fuels reduction project resulted in cut 
wood waste stacked more than a meter high along and on both sides of 
the dirt road at this site, and it was asserted that the cut waste 
effectively blocked all male perching and mate-locating sites in June 
that year (Boyd 2009, p. 3). We interpret the term ``blocked'' to mean 
obstruction of male perching and mate-locating sites as a result of 
these areas being covered by debris. The best available information 
does not indicate that the larval host plant for the Spring Mountains 
acastus checkerspot butterfly occurred abundantly near the road at this 
colony site. Chrysothamnus viscidiflorus was not observed in this area 
after searching the sides of the canyon (Thompson et al. 2012, p. 24) 
where Spring Mountains acastus checkerspot butterflies have been 
historically observed (Weiss et al. 1997, p. 6). However, Spring 
Mountains acastus checkerspot butterflies may be using adjacent areas 
that contain the larval host plant and areas near the road for mate 
locating. Our analysis addresses the alleged impact caused by blocking 
male perching and mate-locating sites.
    The best available information does not indicate if, or to what 
extent, the alleged blocking of male perching sites had occurred at 
this site. The Potosi Mountain/Mt. Potosi/Boy Scout Camp colony site 
was visited two times in 2011, and waste piles were no longer present 
(Service 2011a, pp. 1-3).

[[Page 59365]]

However, wood chips were present near the road and camping areas, but 
had mostly decomposed, with some patches remaining (Service 2011a, pp. 
1-3). Fuel reduction projects likely will reoccur in the future as part 
of wildland-urban interface projects to prevent damage to life or 
property from wildfire; however, the available information does not 
indicate that fuel reduction is impacting the subspecies such that it 
is currently affected at the population level, nor does it indicate 
that it is likely to in the future.
    The best available information indicates that the fuels reduction 
project at the Boy Scouts of America Kimball Scout Reservation, north 
of Potosi Mountain, occurred in April before breeding activity 
occurred, and, thus, breeding adults likely were not disturbed. 
Although the number 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 along the road and in the canyon 
would be available within this site. The Spring Mountains acastus 
checkerspot butterfly has been observed using multiple perch sites 
during mate-locating (Kingsley 2008, pp. 4, 7-8). Because breeding 
occurs during a brief time period, the butterflies use multiple perch 
sites, and they likely exhibit a high breeding success rate (Shields 
1967, p. 123; Rhainds 2010, pp. 212-213), impacts to the Spring 
Mountains acastus butterfly from the fuels reduction project at Potosi 
Mountain/Mt. Potosi/Boy Scout Camp colony site were likely minimal and 
insignificant.
    The fuels reduction project at the Potosi Mountain/Mt. Potosi/Boy 
Scout Camp colony site is localized and will likely occur again in the 
future because maintenance will be required and fires are being 
suppressed. The intensity and exposure of the impact from stacking cut 
waste to the Spring Mountains acastus checkerspot butterfly is low and 
insignificant because the best available information indicates that 
Spring Mountains acastus checkerspot butterflies are able to use more 
than one perching site and that they can successfully breed in only a 
short period of time. We have determined that the stacking of cut waste 
at the Potosi Mountain/Mt. Potosi/Boy Scout Camp colony site is not a 
threat to the Spring Mountains acastus checkerspot butterfly now, nor 
does the available information indicate that it is likely to become a 
threat in the future.
Trough Spring Colony Site
Off-Highway Vehicles
    Information in our files indicates that off-highway vehicles have 
been present at the Trough Spring colony site (Service 2011a, pp. 1-3). 
Off-highway vehicles could adversely affect the Spring Mountains 
acastus checkerspot butterfly by reducing the quantity or quality of 
habitat, reducing survival or fecundity, or directly impacting 
individuals. Off-highway vehicles were observed on the road that goes 
to Trough Spring during the 2011 field season, but no off-highway 
vehicles or signs of vehicle use were observed in Spring Mountains 
acastus checkerspot butterfly habitat with its larval host plant 
present (Service 2011a, pp. 1-3). Any vehicle access from the end of 
the road to Trough Spring and Spring Mountains acastus checkerspot 
butterfly habitat is inhibited by tree downfall and dense shrubs 
resulting from a wildfire (Service 2011a, pp. 1-3). In addition, the 
Trough Spring colony site is partially within the Mt. Charleston 
Wilderness, where motor vehicle use is prohibited.
    The best available information suggests that the Spring Mountains 
acastus checkerspot butterfly is not being affected by off-highway 
vehicles. Although off-highway vehicles will likely continue to use the 
road that goes to Trough Spring in the future, the best available 
information indicates that off-highway vehicles have impacted the 
habitat and the Spring Mountains acastus checkerspot butterfly. 
However, the exposure of the Spring Mountains acastus checkerspot 
butterfly to impacts from off-highway vehicles is insignificant because 
of obstructions described above between the designated road and the 
Trough Spring colony site area. We have determined that off-highway 
vehicle use does not pose a threat to the Spring Mountains acastus 
checkerspot butterfly at the Trough Spring colony site now, nor does 
the available information indicate that it is likely to become one in 
the future.
Horses and Elk
    Horses (Equus ferus) and elk (Cervus elaphus) utilize the Trough 
Spring area (Service 2011a, pp. 1-3; Thompson et al. 2012, p. 22). 
Horses and elk could affect Spring Mountains acastus checkerspot 
butterflies by trampling them when moving through or by feeding in 
areas occupied by all life stages. While horses or elk could cause 
direct mortality, the likelihood of this occurring is probably low 
because: (1) Horses feed predominantly on forbs or grasses (National 
Research Council 1982, pp. 26, 31); (2) elk that may be more likely to 
feed on Chrysothamnus viscidiflorus are more likely to do so in the 
winter (Stubbendieck et al. 2003, p. 249), when larvae are in diapause 
below rocks (Scott 1979, pp. 172, 191; Scott 1986, pp. 27, 307; Opler 
et al. 2011, https://www.butterfliesandmoths.org); (3) eggs or pupae are 
exposed for only a brief period of time in late spring or early summer 
(1 to 3 weeks) (Nunnallee 2011, p. 6; Boyd 2004, p. 3); and (4) if 
larvae are disturbed, they may fall (Wolfe 2004, p. 13) to the ground 
beneath the plant where trampling and feeding may be inhibited by 
thicker shrub branches.
    Overall, the quantity or quality of larval or nectar plant habitat 
for the Spring Mountains acastus checkerspot butterfly may be affected 
by ungulate browsing. Food for Spring Mountains acastus checkerspot 
butterfly larvae may increase under certain browsing regimes. In 
experimental tests on the effects of clipping Chrysothamnus 
viscidiflorus, herbage production was increased when the plants were 
partially defoliated (Willard and McKell 1978, p. 515). Moderate and 
heavy clipping intensities resulted in reduced herbage production 
compared to unclipped C. viscidiflorus shrubs. Based upon these 
results, light defoliation may result in greater herbage production 
than moderate, heavy, and no defoliation. Wild and domestic animals do 
not prefer most subspecies of C. viscidiflorus (Young and Evans 1974, 
p. 469). While horses are considered grazers, they have been observed 
to feed on C. viscidiflorus in the summer (Smith et al., as cited in 
National Research Council 1982, p. 31). During visits to the site in 
2011, browsing at the Trough Spring colony site appeared to be heavy 
(Service 2011a, pp. 1-3). Grazing of grasses or forbs can decrease 
competition for C. viscidiflorus. Subspecies of C. viscidiflorus have 
been observed to vary in palatability to ungulates (McArthur and 
Stevens 2004, p. 532). In the late fall and winter, after more 
desirable forage has been consumed, C. viscidiflorus may be an 
important source of food for game and livestock (McArthur and Stevens 
2004, p. 532).
    Grazing and browsing by horses and elk are localized at the Trough 
Spring colony site, and these activities are expected to continue into 
the future. Because Chrysothamnus viscidiflorus plants are not removed 
and Spring Mountains acastus checkerspot butterfly larvae are able to 
evade browsing animals by falling to the ground when disturbed (Wolfe 
2004, p. 13), the impact of grazing and browsing is likely

[[Page 59366]]

low. If grazing and browsing intensity is moderate to high, however, 
this may result in direct mortality of individuals or a reduction in 
available host plants. The available information does not indicate that 
browsing is negatively impacting the Spring Mountains acastus butterfly 
at the population level; therefore, the best available scientific and 
commercial information does not indicate that ungulates are currently a 
threat to the subspecies, nor are they likely to become so in the 
future.
All Sites
Conservation Efforts to Reduce Habitat Destruction, Modification, or 
Curtailment of Its Range
    The Spring Mountains acastus checkerspot butterfly is listed in the 
SMNRA Conservation Agreement (Forest Service et al. 1998, p. 32) and is 
considered under a 2004 voluntary memorandum of agreement (MOA) between 
the Forest Service and the Service (Forest Service and Fish and 
Wildlife Service 2004, p. 1). The MOA was designed to establish a 
general framework for a streamlined process for interagency cooperation 
between the Humboldt-Toiyabe National Forest and the Service (Forest 
Service and Fish and Wildlife Service 2004, p. 1). The conservation 
agreement was in effect from April 13, 1998, to 2008 (Forest Service et 
al. 1998, pp. 44, 49), when it was renewed (Forest Service 2008). The 
conservation agreement is still being implemented. A new conservation 
agreement is currently being developed for the SMNRA. The conservation 
agreement, MOA, and Clark County Multiple Species Habitat Conservation 
Plan (MSHCP) guide and assist agency planning for Spring Mountains 
acastus checkerspot butterfly habitat and population monitoring. The 
conservation agreement and MOA facilitate protection-oriented resource 
management that considers conservation values through early project 
planning, as well as species, habitat, and ecosystem inventory, 
protection, monitoring, restoration, research, and education (Forest 
Service et al. 1998, p. 1), which may help alleviate negative impacts 
to the butterfly. Voluntary conservation actions from the conservation 
agreement (Forest Service et al. 1998, pp. 1-50) are also found in the 
MSHCP (RECON 2000c pp. A-79-A-88).
Summary of Factor A
    We do not find highway modification and power line maintenance, 
hazardous fuels reduction projects, equestrian traffic, off-highway 
vehicle use, and browsing by horses or elk to be threats to the Spring 
Mountains acastus checkerspot butterfly. Although fire suppression has 
been suggested to negatively impact Spring Mountains acastus 
checkerspot butterfly habitat, the available information does not 
suggest that changes to fire frequency or changes in habitat quality or 
quantity such that fire suppression is currently a threat to the 
subspecies or likely to become one in the future. In addition, the 
available information does not indicate that habitat is a limiting 
factor for the Spring Mountains acastus checkerspot butterfly now or 
likely to become so in the future. Based upon our review of the best 
available scientific and commercial information, we find that the 
present or threatened destruction, modification, or curtailment of its 
habitat or range is not a threat to the Spring Mountains acastus 
checkerspot butterfly, nor is it likely to become so in the future.

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

    In areas surrounding the range of the Spring Mountains acastus 
checkerspot butterfly, sagebrush checkerspot butterflies have been 
confiscated from illegal commercial traders (U.S. Attorney's Office 
1994, pp. 23, 47; Alexander 1996, pp. 1-6). One sagebrush checkerspot 
was removed from the Grand Canyon National Park in 1985, and 14 were 
removed from Death Valley National Park in 1987 (U.S. Attorney's Office 
1994, pp. 23 and 47), but it is unknown whether any sagebrush 
checkerspot butterflies have been collected for unauthorized commercial 
use in the Spring Mountains. The Spring Mountains are located between 
Grand Canyon National Park to the east (approximately 300 km (180 mi)) 
and Death Valley National Park to the west (approximately 130 km (80 
mi)). There is no available information regarding the utilization of 
Spring Mountains acastus checkerspot butterflies for unauthorized 
commercial purposes.
    Spring Mountains acastus checkerspot butterflies have been 
collected for authorized commercial use, including for scientific and 
educational purposes. We infer that the earliest collections of Spring 
Mountains acastus checkerspot butterflies are from the 1920s, based on 
Boyd and Austin (1999, p.19). Most documented collections of Spring 
Mountains acastus checkerspot butterfly have occurred for scientific or 
educational purposes (Table 3). On Forest Service-administered lands, a 
special use permit is required for the commercial collection of 
butterflies (36 CFR 251.50), which would include collections for 
research, museums, universities, or professional societies (Forest 
Service 2003, pp. 2-3).

  Table 3--Numbers of Spring Mountains Acastus Checkerspot Butterfly Specimens Collected by Area, Year, and Sex
                                          Found in Published Documents
----------------------------------------------------------------------------------------------------------------
              Collection area/year                     Male           Female          Unknown          Total
----------------------------------------------------------------------------------------------------------------
Deer Cr. Rd.
    1950........................................  ..............  ..............               1               1
    1965........................................               1  ..............  ..............               1
    1977........................................               6               2  ..............               8
    1981........................................  ..............               3  ..............               3
                                                 ---------------------------------------------------------------
        Deer Cr. Rd. Total......................               7               5               1              13
 
Spring Mountains (general reference)
    1934........................................              10               1  ..............              11
    2002........................................  ..............  ..............               2               2
Harris Spring Rd./Harris Mountain Rd.
    1990........................................              16               6  ..............              22
    1999........................................               2               2  ..............               4
Griffith Peak Trail
    2002........................................  ..............  ..............            4\L\               4

[[Page 59367]]

 
Kyle Canyon
    1950........................................  ..............  ..............               2               2
    1965........................................               2  ..............              62              64
    1974........................................               1               2  ..............               3
    1977........................................              15               2  ..............              17
    1978........................................               6               1  ..............               7
    1979........................................              41               3  ..............              44
    1981........................................               8               1  ..............               9
    1987........................................              17               5  ..............              22
    1988........................................               5  ..............  ..............               5
    1989........................................              28               5  ..............              33
    1990........................................              13               2  ..............              15
    2006........................................  ..............  ..............               2               2
                                                 ---------------------------------------------------------------
        Kyle Canyon Total.......................             136              21              66             223
 
Willow-Cold Creek
    1979........................................               1  ..............  ..............               1
                                                 ---------------------------------------------------------------
        Area Totals.............................             172              35              73  ..............
                                                 ---------------------------------------------------------------
            Total...............................  ..............  ..............  ..............             280
----------------------------------------------------------------------------------------------------------------
References: Austin and Austin 1980, p. 40; Austin 1998, p. 576; Boyd 2004, p. 3; Boyd et al. 2000, p. 7; Jones
  and Stokes 2007a, Service 2012, pp. 1-4, and YPM ENT Catalog (https://peabody.yale.edu/collections/search-collections?ent) Note: duplicate specimens from Austin and Austin 1980 and Austin 1998 have been accounted
  for.
\L\ = larvae

    Prior to 2006, collecting for noncommercial (recreational and 
personal) purposes did not require a collecting permit issued by the 
Regional Forester in most areas (Forest Service 1998, p. 1; Joslin 
1998, p. 74). Since 1996 within the SMNRA, Lee Canyon, Cold Creek, 
Willow Creek, and upper Kyle Canyon have been identified as areas where 
permits are required for any butterfly collecting (Forest Service 1996, 
pp. 28, E9). There are no records indicating that special use permits 
have been issued for commercial or noncommercial collecting of Spring 
Mountains acastus checkerspot butterflies in the Spring Mountains (S. 
Hinman 2011, pers. comm.). However, there are published and unpublished 
documented accounts of collections from the Spring Mountains (Austin 
and Austin 1980, p. 40; Austin 1998, p. 576; Boyd 2004, p. 3; Jones and 
Stokes 2007a, Table 5; Service 2012, pp. 1-4; YPM ENT Catalog, https://peabody.yale.edu/collections/search-collections?ent) (see Table 3 for 
references).
    The best available information indicates that Spring Mountains 
acastus checkerspot butterflies have been collected for personal use 
(Service 2012, pp. 1-4). In some cases, private collectors have more 
extensive collections of particular species than museums (Alexander 
1996, p. 2). Published and unpublished accounts of Spring Mountains 
acastus checkerspot butterfly specimens in collections vary, with 
typically more males collected than females during any year (Table 3). 
Documented specimens indicate that most collections are from the Kyle 
Canyon area. A survey of butterfly collectors in The Lepidopterists' 
Society in the Northwest showed that approximately one-third of the 
respondents indicated that they collected for personal collections, 
another third collected for research or museum collections, and the 
remainder fell within categories that may count for either (Mazzei and 
Shapiro 2001, p. 103).
    The collection of butterflies in general results in the direct 
mortality of individuals and, when a population is small, may affect 
the population's ability to recover. Butterfly collecting is generally 
thought to have less of an impact on butterfly populations compared to 
other threats; however, populations already stressed by other factors 
may be threatened by intensive collecting (Thomas 1984, p. 345; Miller 
1994, pp. 76, 83; New et al. 1995, p. 62). Thomas 1984 (p. 345) 
suggested that closed, sedentary populations of fewer than 250 adults 
are most likely to be at risk from overcollection. While there is 
little documentation of the extirpation of any butterfly species as a 
result of overcollecting (Miller 1994, p. 76), it has been shown that 
removing a large number of female specimens from a population may 
result in a greater threat of population decline (Hayes 1981, p. 197) 
and potentially hasten the extinction of a species (Thomas 1984, p. 
341).
    The reported observed or captured sex ratio (males:females) in 
Spring Mountains acastus checkerspot butterflies is strongly biased 
(170:33) towards males (Table 3). Although many factors can affect the 
differences between the observed and actual sex ratios, which vary 
between years (Ehrlich et al. 1984, pp. 527-539; Boggs and Nieminen 
2004, pp. 92-94), the magnitude of this difference suggests that this 
bias is real, and that there are typically fewer females than males in 
Spring Mountains acastus checkerspot butterfly populations. Because 
males and females are similar in appearance, it may be difficult for 
most collectors to selectively capture either sex.
    There is no available information regarding the utilization of 
Spring Mountains acastus checkerspot butterflies for commercial 
purposes (other than for scientific and educational purposes) in the 
past, or information to indicate a historic, current, or future demand. 
The Spring Mountains acastus checkerspot butterfly has been collected 
historically for recreational, scientific, and educational purposes. 
Published accounts of collections for management or scientific purposes 
indicate that collecting Spring Mountains acastus checkerspot 
butterflies has become less frequent in the last couple of decades 
(Table 3).

[[Page 59368]]

Summary of Factor B
    Survey data indicate abundances may be low, but we do not know 
actual population numbers of the Spring Mountains acastus checkerspot 
butterfly. Therefore, the percentage of the population of Spring 
Mountains acastus checkerspot butterfly that has been removed through 
collecting is unknown. However, the number of reported Spring Mountains 
acastus checkerspot butterflies collected has declined in recent 
decades, and the available information does not indicate that 
collection has had an adverse effect on the species, or nor is it 
likely to have an adverse effect in the future. Nonetheless, because 
collection is known to occur, we will work with the Forest Service to 
enhance the effectiveness of their permitting program and continue to 
monitor abundance and collection efforts. Based upon our review of the 
best available scientific and commercial information, we find that 
overutilization for commercial, recreational, scientific or educational 
purposes is not a threat to the Spring Mountains acastus checkerspot 
butterfly now, nor is it likely to become so in the future.

Factor C. Disease or Predation

    There is no available information regarding any impacts from either 
disease or predation on the Spring Mountains acastus checkerspot 
butterfly. Therefore, based on the best available scientific and 
commercial information, we do not find disease or predation to be 
threats to the Spring Mountains acastus checkerspot butterfly now, nor 
are they likely to become so in the future.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    Existing regulatory mechanisms or other agreements that could 
provide some protection for the Spring Mountains acastus checkerspot 
butterfly include: (1) Local land use laws, processes, and ordinances; 
(2) State laws and regulations; and (3) Federal laws and regulations. 
Actions adopted by local groups, States, or Federal entities that are 
discretionary, including conservation strategies and guidance, are not 
regulatory mechanisms; however, we will discuss and evaluate them 
below. The Spring Mountains acastus checkerspot butterfly primarily 
occurs on Federal land under the jurisdiction of the Forest Service; 
therefore, our discussion will primarily focus on Federal laws.
Local Laws and Ordinances
    There is no available information regarding local land use laws and 
ordinances that have been issued by Clark County or other local 
government entities for protection of the Spring Mountains acastus 
checkerspot butterfly.
State Law
    Nevada Revised Statute sections 503 and 527 offer protective 
measures to wildlife and plants, but do not include invertebrate 
species such as the Spring Mountains acastus checkerspot butterfly. 
Therefore, no regulatory protection is offered under Nevada State law.
Federal Law
    Spring Mountains acastus checkerspot butterflies have been detected 
consistently in four known colony sites in recent years. Three of the 
colony sites, Griffith Peak Trail/Harris Spring Road/Harris Mountain 
Road, Kyle Canyon (middle), and Trough Spring, are located mainly on 
Federal land. Large portions of the Griffith Peak Trail and Trough 
Spring colony sites are located within the Mt. Charleston Wilderness. 
The Forest Service manages lands designated as wilderness under the 
Wilderness Act of 1964 (16 U.S.C. 1131-1136). Within these areas, the 
Wilderness Act states the following: (1) New or temporary roads cannot 
be built; (2) there can be no use of motor vehicles, motorized 
equipment, or motorboats; (3) there can be no landing of aircraft; (4) 
there can be no other form of mechanical transport; and (5) no 
structure or installation may be built. As such, the majority of Spring 
Mountains acastus checkerspot butterfly habitat in the Griffith Peak 
Trail and Trough Springs area is protected from direct loss and 
degradation by the prohibitions of the Wilderness Act. Spring Mountains 
acastus checkerspot butterfly habitat at Kyle Canyon, Potosi Mountain, 
along the Harris Spring and Harris Mountains Road, and elsewhere is 
located outside of the Mt. Charleston Wilderness, and, thus, it is not 
subject to protections afforded by the Wilderness Act.
    The National Environmental Policy Act of 1969, as amended (NEPA) 
(42 U.S.C. 4321 et seq.), requires Federal agencies, such as the Forest 
Service, to describe proposed agency actions, consider alternatives, 
identify and disclose potential environmental impacts of each 
alternative, and involve the public in the decision-making process. 
Federal agencies are not required to select the NEPA alternative having 
the least significant environmental impacts. A Federal agency may 
select an action that will adversely affect sensitive species, provided 
that these effects are identified in a NEPA document. NEPA itself is a 
disclosure law, and does not require subsequent minimization or 
mitigation of actions taken by Federal agencies. Although Federal 
agencies may include conservation measures for the Spring Mountains 
acastus checkerspot butterfly as a result of the NEPA process, such 
measures are not required by the statute. The Forest Service is 
required to analyze its projects in accordance with NEPA.
    The SMNRA is 1 of 10 districts of the Humboldt-Toiyabe National 
Forest. Public Law 103-63, dated August 4, 1993 (the Spring Mountains 
National Recreation Area Act, 16 U.S.C. 460hhh et seq.), established 
the SMNRA to include approximately 316,000 acres (128,000 hectares) of 
Federal lands managed by the Forest Service in Clark and Nye Counties, 
Nevada, for the following purposes:
    (1) To preserve the scenic, scientific, historic, cultural, 
natural, wilderness, watershed, riparian, wildlife, threatened and 
endangered species, and other values contributing to public enjoyment 
and biological diversity in the Spring Mountains of Nevada;
    (2) To ensure appropriate conservation and management of natural 
and recreation resources in the Spring Mountains; and
    (3) To provide for the development of public recreation 
opportunities in the Spring Mountains for the enjoyment of present and 
future generations.
    The National Forest Management Act of 1976, as amended (NFMA) (16 
U.S.C. 1600 et seq.), provides the principal guidance for the 
management of activities on lands under Forest Service jurisdiction 
through associated land and resource management plans for each forest 
unit. Under NFMA and other Federal laws, the Forest Service has the 
authority to regulate recreation, vehicle travel, and other human 
disturbance; livestock grazing; fire management; energy development; 
and mining on lands within its jurisdiction. Current guidance for the 
management of Forest Service lands in the SMNRA is under the Toiyabe 
National Forest Land and Resource Management Plan and the SMNRA General 
Management Plan. In June 2006, the Forest Service added the Spring 
Mountains acastus checkerspot butterfly and three other endemic 
butterflies to the Regional Forester's Sensitive Species List in 
accordance with Forest Service Manual 2670. The Forest Service's 
objective in managing

[[Page 59369]]

sensitive species is to prevent listing of species under the Act, 
maintain viable populations of native species, and develop and 
implement management objectives for populations and habitat of 
sensitive species. Projects listed under Factor A above for the Kyle 
Canyon (middle) colony site have been guided by these Forest Service 
plans, policies, and guidance. However, removal or degradation of 
butterfly habitat has occurred as a result of projects approved by the 
Forest Service in Kyle Canyon.
    Because the Spring Mountains acastus checkerspot butterfly is 
designated a sensitive species, Standard 0.28 of the Land and Resource 
Management Plan for the Spring Mountains requires a collecting permit 
issued by the Regional Forester (except for traditional use by American 
Indians) (Forest Service 1996, p. 18). Furthermore, Standard 11.6 
indicates that collecting, regardless of species, in specific areas 
including Cold Creek, Lee Canyon, upper Kyle Canyon, and Willow Creek 
also requires a permit (Forest Service 1996, p. 31). These items, 
identified as ``standards,'' are constraints or mitigation measures 
that must be followed as directed by the General Management Plan 
(Forest Service 1996, p. 2). Collection permits are not required for 
activities contracted by or performed under agreement with the Forest 
Service. The best available information indicates that collecting has 
occurred before and after the Spring Mountains acastus checkerspot 
butterfly was designated a sensitive species (see Factor B discussion 
above); however, no permits have been issued to date.
Summary of Factor D
    The current existing regulatory mechanism designed to regulate the 
collection of Spring Mountains acastus checkerspot butterflies exists, 
but there are no records of permits being issued for this purpose. 
Despite the existence of the permitting program, collections of Spring 
Mountains acastus checkerspot butterfly and other species of 
butterflies have taken place without permits being issued. We are 
unable at this time to determine the current population abundance or 
trends for the Spring Mountains acastus checkerspot butterfly. We 
concluded that collection is not a threat to the subspecies. Therefore, 
we cannot conclude that existing regulatory mechanisms regarding 
collection are inadequate. However, because butterfly collection is 
known to occur in the Spring Mountains, we will work with the Forest 
Service to enhance the effectiveness of their permitting program and 
continue to monitor abundance and collection efforts. After reviewing 
the best available commercial and scientific information, we conclude 
that the inadequacy of existing regulatory mechanisms is not currently 
a threat to the Spring Mountains acastus checkerspot butterfly, nor is 
it likely to become so because our analysis under the other Factors 
concluded that there are no significant threats to the species.

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

Drought at All Sites
    Drought is variously defined depending upon the temporal and 
spatial scales of interest (Heim 2002, p. 1150; Passioura 2007, p. 
113). We consider drought in the context of reduced water availability 
that would affect Spring Mountains acastus checkerspot butterfly larval 
host and nectar plants at a magnitude sufficient to cause a decline in 
the population. Climate models show the southwestern United States has 
transitioned into a more arid climate of drought that is predicted to 
continue into the next century (Seager et al. 2007, p. 1181).
    Reductions in butterfly populations due to drought have been 
observed (Ehrlich et al. 1980, pp. 101-105; Thomas 1984, p. 344). In 
2006, populations of many butterfly species were at low levels 
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). Because other species of butterflies 
in the Spring Mountains experienced declines thought to be associated 
with drought, we believe that drought could affect the Spring Mountains 
acastus checkerspot butterfly similarly. However, we do not have 
information about Spring Mountains acastus checkerspot butterfly 
abundance trends as they relate to drought occurrences in order to 
determine at this time if drought may affect the subspecies now or in 
the future.
    The Spring Mountains acastus checkerspot butterfly's larval host 
plant, Chrysothamnus viscidiflorus, is classified as having a ``high'' 
drought tolerance (USDA Natural Resources Conservation Service (NRCS) 
2011); however, certain soil characteristics, such as loam (a soil 
consisting of a mixture of varying proportions of clay, silt, and 
sand), can reduce its tolerance to drought (Sperry and Hacke 2002, p. 
367). We do not have information on where such soil characteristics 
occur in the Spring Mountains and whether they occur in Spring 
Mountains acastus checkerspot butterfly habitat. Additionally, C. 
viscidiflorus is at a competitive disadvantage for limited early spring 
moisture because of its low leaf area (Miller 1988, p. 62). Drought can 
cause butterfly host plants to mature early, which can reduce larval 
food availability (Ehrlich et al. 1980, pp. 101-105; Weiss 1987, p. 
165). The available information about drought does not indicate that 
Spring Mountains acastus checkerspot butterfly host plants are maturing 
early and therefore reducing larval food availability for the 
subspecies. Therefore, we cannot speculate about the effects of drought 
on the Spring Mountains acastus checkerspot butterfly.
    Precipitation during the growing season for Chrysothamnus 
viscidiflorus (April through July) has exhibited an overall decline 
during the last decade at three climate stations in and around the 
Spring Mountains (Service 2011c, pp. 1-3). The Spring Mountains acastus 
checkerspot butterfly population may be experiencing drought conditions 
associated with this decline in precipitation. However, because the 
larval host plant is drought-tolerant and the available information 
does not indicate how individual Spring Mountains acastus checkerspot 
butterflies may be impacted by drought, we have determined that, based 
on the best available scientific and commercial information, drought is 
not a threat to the subspecies at this time, nor is it likely to become 
a threat in the future.
Small Populations
    Populations with small numbers of individuals have a higher risk of 
extinction than populations with large numbers of individuals due to 
random environmental events (Shaffer 1981, p. 131; Gilpin and Soule 
1986, pp. 24-28; Shaffer 1987, pp. 69-75). The number of surveyed 
individuals of Spring Mountains acastus checkerspot butterflies has 
remained small over the last 5 years (Table 2); however the available 
information does not indicate that historical or recent population size 
for the Spring Mountains acastus checkerspot butterfly have declined 
such that small population size may be a threat to the subspecies now, 
nor is it likely to become so in the future.
    We are unable at this time to determine with any certainty the 
current population abundance or trends of the Spring Mountains acastus 
checkerspot butterfly. At the four sites where survey data exist, it 
appears that abundances have consistently been low. Surveying

[[Page 59370]]

for butterflies may pose difficulties because of low densities, limited 
resources, route considerations, surveyor experience, and varying 
weather conditions (Zonneveld et al. 2003, pp. 476-486). On the basis 
of a review of the available information and given the uncertainty 
about abundance and trends, we cannot conclude that small population 
size is a threat to the subspecies at this time, nor does available 
information indicate it is likely to become so in the future.
Vehicle and Hiking Traffic at the Griffith Peak Trail/Harris Spring 
Road/Harris Mountain Road Colony Site
    One researcher has hypothesized that disturbance by vehicle and 
hiking traffic may threaten the Griffith Peak Trail/Harris Spring Road/
Harris Mountain Road colony site as a result of direct disturbance to 
the butterflies by vehicles and hikers (Boyd 2009, pp. 3-4). Vehicles 
and hikers could affect Spring Mountains acastus checkerspot 
butterflies by altering the behavior of the butterflies and causing 
adult mortality from crushing or collision. Road and trail use are 
likely to continue into the future. The Harris Spring Road leads to 
Harris Mountain Road, where Spring Mountains acastus checkerspot 
butterflies have been observed (Boyd and Austin 2001, Figure 1). This 
is a rough gravel road with switchbacks that restrict vehicle speeds. 
Visitor use during weekdays is low (Service 2011, p. 1), but likely 
increases on the weekends. Mortality caused by crushing or collision 
with vehicles would likely be rare because vehicles are unlikely to 
attain speeds beyond those that butterflies could escape from. Exposure 
of Spring Mountains acastus checkerspot butterflies to disturbance from 
hikers is insignificant because the best available data indicate that 
disturbance is sporadic and limited, allowing sufficient time for 
mating to occur. Studies of sagebrush checkerspot butterflies have 
shown that they have a high breeding success (Shields 1967, pp. 90 and 
123; Rhainds 2010, pp. 212-213), and Spring Mountains acastus 
checkerspot butterflies are likely similar. After females mate, they 
disperse to oviposit, apparently away from the colony site breeding 
areas (Boyd and Austin 2001, p. 6; Boyd and Austin 2002, p. 5). 
Disturbance by vehicles and hikers is localized, ongoing, and low in 
intensity. Exposure of Spring Mountains acastus checkerspot butterflies 
to these activities is insignificant based upon our review of the best 
available information. Therefore, we have determined that disturbance 
from vehicles and hikers is not a threat to the Spring Mountains 
acastus checkerspot butterfly now, nor is it likely to be a threat in 
the future.
Summary of Factor E
    Drought has occurred and is expected to continue throughout the 
range of the Spring Mountains acastus checkerspot butterfly and may 
negatively impact the subspecies. However, the larval host plant is 
drought-tolerant, and the available information does not indicate that 
individual Spring Mountains acastus checkerspot butterfly populations 
have been impacted by drought such that drought is a threat to the 
Spring Mountains acastus checkerspot butterfly now, nor is it likely to 
become a threat in the future. The available information does not 
indicate that small population size is a threat to the subspecies at 
this time, nor is it likely to become so in the future given the 
uncertainty about abundance and number of colonies. In addition, the 
available information indicates that disturbance from vehicles and 
hikers is not a threat to the Spring Mountains acastus checkerspot 
butterfly because disturbance by vehicles and hikers is localized, 
ongoing, and low in intensity. Based on our review of the best 
available scientific and commercial information, there is no indication 
that other natural or manmade factors are a threat to the subspecies at 
this time, nor are they likely to become so in the future.

Cumulative Effects From Factors A Through E

    We considered whether there may be cumulative effects to the Spring 
Mountains acastus checkerspot butterfly from the combined impacts of 
potential threats such that even if each threat individually does not 
result in population-level impacts, that cumulatively the effects may 
be significant. We considered whether the combined effects of fire 
suppression, collection, climate change, and small population size may 
result in a significant impact to the Spring Mountains acastus 
checkerspot butterfly. At this time, given the complex and uncertain 
nature of effects associated with climate change and the uncertainties 
associated with information on the abundance and population trends of 
the Spring Mountains acastus checkerspot butterfly, the best available 
information does not indicate that synergistic interactions between 
climate change and the other potential threats (fire suppression, 
collection, and small population size) will impact the Spring Mountains 
acastus checkerspot butterfly. Even though each of these potential 
threats may result in an impact to the Spring Mountains acastus 
checkerspot butterfly, the best available information does not indicate 
that synergistic effects between fire suppression, collection, climate 
change, and small population size are unlikely to result in a 
significant overall population impact to the Spring Mountains acastus 
checkerspot butterfly now, nor are they likely to do so in the future.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the Spring Mountains acastus checkerspot butterfly is an 
endangered or threatened species throughout all of its range. We 
examined the best scientific and commercial information available 
regarding the past, present, and future threats faced by the Spring 
Mountains acastus checkerspot butterfly. We reviewed the petition, 
information available in our files, other available published and 
unpublished information, and we consulted with recognized Spring 
Mountains acastus checkerspot butterfly experts and other Federal 
agencies.
    The term ``threatened species'' means any species (or subspecies 
or, for vertebrates, distinct population segments) that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act does not define the 
term ``foreseeable future.'' However, it likely describes the extent to 
which the Service could reasonably rely on predictions about the future 
in making determinations about the future conservation status of the 
species.
    In considering the foreseeable future as it relates to the status 
of the Spring Mountain Acastus butterfly we considered the best 
available scientific and commercial historical and current data to 
identify any existing trends or indications that conditions are likely 
to change in the future. We considered how current stressors are 
affecting the species and if that information indicates any changes in 
those stressors in the future. Thus the foreseeable future includes 
consideration of the ongoing effects of current stressors and whether 
there are likely to be any changes in the stressor in the future that 
will result in population level effects.
    Based on our review of the best available scientific and commercial 
information pertaining to the five factors, we find that the stressors 
to the subspecies or its habitat are not of sufficient imminence, 
intensity, or

[[Page 59371]]

magnitude to indicate that the Spring Mountains acastus checkerspot 
butterfly is in danger of extinction (endangered), or likely to become 
endangered within the foreseeable future (threatened), throughout all 
or a significant portion of its range. While the best available 
information indicates that survey numbers are low, it does not suggest 
a significant change in distribution or abundance of the Spring 
Mountains acastus checkerspot butterfly. Further, the best available 
information does not indicate that any threats are acting on the 
subspecies. Fire suppression has impacted other butterfly species in 
the Spring Mountains, but the best available information does not 
indicate that the larval host plant for the Spring Mountains acastus 
checkerspot butterfly has been reduced in abundance and distribution as 
a result of fire suppression. Additionally, while we are aware of 
butterfly collection in the Spring Mountains, the best available 
information does not indicate that population abundances of the Spring 
Mountains acastus checkerspot butterfly are being negatively impacted 
by collection. We are currently working with the Forest Service to 
address collection permitting and prohibitions to avoid any potential 
future threats that could occur from collection. Additionally, the best 
available information does not indicate that any of these stressors are 
likely to change such that they are likely to have population level 
impacts on the subspecies in the future. Therefore, we find that 
listing the Spring Mountains acastus checkerspot butterfly as an 
endangered or threatened species is not warranted throughout all of its 
range at this time.

Significant Portion of the Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is an endangered or threatened species throughout 
all or a significant portion of its range. The Act defines ``endangered 
species'' as any species which is ``in danger of extinction throughout 
all or a significant portion of its range,'' and ``threatened species'' 
as any species which is ``likely to become an endangered species within 
the foreseeable future throughout all or a significant portion of its 
range.'' The definition of ``species'' is also relevant to this 
discussion. The Act defines ``species'' as follows: ``The term 
`species' includes any subspecies of fish or wildlife or plants, and 
any distinct population segment of any species of vertebrate fish or 
wildlife which interbreeds when mature.'' The phrase ``significant 
portion of its range'' (SPR) is not defined by the statute, and we have 
never addressed in our regulations: (1) The consequences of a 
determination that a species is either endangered or likely to become 
so throughout a significant portion of its range, but not throughout 
all of its range; or (2) what qualifies a portion of a range as 
``significant.''
    In determining whether the Spring Mountains acastus checkerspot 
butterfly is an endangered or threatened species in a significant 
portion of its range, we first addressed whether any portions of the 
range of the Spring Mountains acastus checkerspot butterfly warrant 
further consideration. We evaluated the current range of the Spring 
Mountains acastus checkerspot butterfly to determine if there is any 
apparent geographic concentration of the primary stressors potentially 
affecting the subspecies. We found the stressors are not of sufficient 
imminence, intensity, or magnitude, and are not geographically 
concentrated such that it warrants evaluating whether a portion of the 
range is significant under the Act.
    We do not find that the Spring Mountains acastus checkerspot 
butterfly is in danger of extinction now, nor is likely to become 
endangered within the foreseeable future, throughout all or a 
significant portion of its range. Therefore, listing the Spring 
Mountains acastus checkerspot butterfly as an endangered or threatened 
species under the Act is not warranted at this time.
    We request that you submit any new information concerning the 
status of, or threats to, the Spring Mountains acastus checkerspot 
butterfly to our Nevada Fish and Wildlife Offices (see ADDRESSES 
section) whenever it becomes available. New information will help us 
monitor the Spring Mountains acastus checkerspot butterfly and 
encourage its conservation. If an emergency situation develops for the 
Spring Mountains acastus checkerspot butterfly or any other species, we 
will act to provide immediate protection.

References Cited

    A complete list of references cited is available on the Internet at 
https://www.regulations.gov and upon request from the Nevada Fish and 
Wildlife Office (see ADDRESSES section).

Authors

    The primary authors of this notice are the staff members of the 
Nevada Fish and Wildlife Office and the Pacific Southwest Regional 
Office.

Authority

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

    Dated: September 19, 2012.
Rowan W. Gould,
Acting Director, Fish and Wildlife Service.
[FR Doc. 2012-23739 Filed 9-26-12; 8:45 am]
BILLING CODE 4310-55-P