Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List 10 Subspecies of Great Basin Butterflies as Threatened or Endangered With Critical Habitat, 61532-61554 [2011-25324]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 192 (Tuesday, October 4, 2011)]
[Proposed Rules]
[Pages 61532-61554]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-25324]



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Vol. 76

Tuesday,

No. 192

October 4, 2011

Part III





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; 90-Day Finding on a 
Petition To List 10 Subspecies of Great Basin Butterflies as Threatened 
or Endangered With Critical Habitat; Proposed Rule

Federal Register / Vol. 76 , No. 192 / Tuesday, October 4, 2011 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2010-0097; 92210-1111-0000-B2]


Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition To List 10 Subspecies of Great Basin Butterflies as 
Threatened or Endangered With Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of petition finding and initiation of status review.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding on a petition to list 10 subspecies of Great Basin 
butterflies in Nevada and California as threatened or endangered under 
the Endangered Species Act of 1973, as amended (Act), and designate 
critical habitat. Based on our review, we find that the petition 
presents substantial scientific or commercial information indicating 
that listing the following 4 of the 10 subspecies as threatened or 
endangered may be warranted: Baking Powder Flat blue butterfly, 
bleached sandhill skipper, Steptoe Valley crescentspot, and White River 
Valley skipper. Therefore, with the publication of this notice, we are 
initiating a review of the status of these four subspecies to determine 
if listing these subspecies is warranted. To ensure that this status 
review is comprehensive, we are requesting scientific and commercial 
data and other information regarding these four subspecies. Based on 
the status review, we will issue a 12-month finding on these four 
subspecies, which will address whether the petitioned action is 
warranted under the Act.
    We find that the petition does not present substantial scientific 
or commercial information indicating that listing the remaining 6 of 
the 10 subspecies as threatened or endangered may be warranted: Carson 
Valley silverspot, Carson Valley wood nymph, Mattoni's blue butterfly, 
Mono Basin skipper, and the two Railroad Valley skipper subspecies. 
However, we ask the public to submit to us any new information that 
becomes available concerning the status of, or threats to, these four 
subspecies or their habitat at any time.

DATES: To allow us adequate time to conduct this review, we request 
that we receive information on or before December 5, 2011. Please note 
that if you are using the Federal eRulemaking Portal (see ADDRESSES 
section, below), the deadline for submitting an electronic comment is 
11:59 p.m. Eastern Standard Time on this date. After December 5, 2011, 
you must submit information directly to the Field Office (see FOR 
FURTHER INFORMATION CONTACT section below). Please note that we might 
not be able to address or incorporate information that we receive after 
the above requested date.

ADDRESSES: You may submit information by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments to Docket No. FWS-R8-
ES-2010-0097. Check the box that reads ``Open for Comment/Submission,'' 
and then click the Search button. You should then see an icon that 
reads ``Submit a Comment.'' Please ensure that you have found the 
correct rulemaking before submitting your comment.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: Docket No. FWS-R8-ES-2010-0097; Division of Policy and Directives 
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 
2042-PDM; Arlington, VA 22203.
    We will post all information we receive on https://www.regulations.gov. This generally means that we will post any 
personal information you provide us (see the Request for Information 
section below for more details).

FOR FURTHER INFORMATION CONTACT: Jill A. Ralston, Acting State 
Supervisor, Nevada Fish and Wildlife Office, U.S. Fish and Wildlife 
Service, 1340 Financial Blvd., Suite 234, Reno, NV 89502, by telephone 
(775-861-6300), or by facsimile (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: We announce a 90-day finding on a petition 
to list 10 subspecies of Great Basin butterflies in Nevada and 
California as threatened or endangered under the Act and designate 
critical habitat. The petitioners had requested that we list following 
10 subspecies of Great Basin butterflies in Nevada and California as 
threatened or endangered under the Act and designate critical habitat: 
Baking Powder Flat blue butterfly (Euphilotes bernardino minuta), Mono 
Basin skipper (Hesperia uncas giulianii), bleached sandhill skipper 
(Polites sabuleti sinemaculata), Railroad Valley skipper (Hesperia 
uncas fulvapalla), Carson Valley silverspot (Speyeria nokomis 
carsonensis), Railroad Valley skipper (Hesperia uncas reeseorum), 
Carson Valley wood nymph (Cercyonis pegala carsonensis), Steptoe Valley 
crescentspot (Phyciodes cocyta arenacolor), Mattoni's blue butterfly 
(Euphilotes pallescens mattonii), and White River Valley skipper 
(Hesperia uncas grandiose).
    Based on our review, we find that the petition presents substantial 
scientific or commercial information indicating that listing 4 of the 
10 subspecies as threatened or endangered may be warranted, and we find 
that the petition does not present substantial scientific or commercial 
information indicating that listing the remaining 6 of the 10 
subspecies as threatened or endangered may be warranted.

Request for Information

    When we make a finding that a petition presents substantial 
information indicating that listing a species may be warranted, we are 
required to promptly review the status of the species (status review). 
For the status review to be complete and based on the best available 
scientific and commercial information, we request information on the 
four subspecies of butterflies from governmental agencies, Native 
American Tribes, the scientific community, industry, and any other 
interested parties. We seek information on:
    (1) The species' biology, range, and population trends, including:
    (a) Habitat requirements for feeding, breeding, and sheltering;
    (b) Genetics and taxonomy;
    (c) Historical and current range including distribution patterns;
    (d) Historical and current population levels, and current and 
projected trends; and
    (e) Past and ongoing conservation measures for the species, its 
habitat or both.
    (2) The factors that are the basis for making a listing 
determination for a species under section 4(a) of the Act (16 U.S.C. 
1531 et seq.), which are:
    (a) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (b) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (c) Disease or predation;
    (d) The inadequacy of existing regulatory mechanisms; or
    (e) Other natural or manmade factors affecting its continued 
existence.
    If, after the status review, we determine that listing any of the 
six subspecies is warranted, we will propose critical habitat (see 
definition in section 3(5)(A) of the Act), under

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section 4 of the Act, to the maximum extent prudent and determinable at 
the time we propose to list the species. Therefore, within the 
geographical range currently occupied by the six subspecies, we request 
data and information on:
    (1) What may constitute ``physical or biological features essential 
to the conservation of the species'';
    (2) Where these features are currently found; and
    (3) Whether any of these features may require special management 
considerations or protection.
    In addition, we request data and information on ``specific areas 
outside the geographical area occupied by the species'' that are 
``essential to the conservation of the species.'' Please provide 
specific comments and information as to what, if any, critical habitat 
you think we should propose for designation if any of the six 
subspecies are proposed for listing, and why such habitat meets the 
requirements of section 4 of the Act.
    Please include sufficient information with your submission (such as 
scientific journal articles or other publications) to allow us to 
verify any scientific or commercial information you include.
    Submissions merely stating support for or opposition to the action 
under consideration without providing supporting information, although 
noted, will not be considered in making a determination. Section 
4(b)(1)(A) of the Act directs that determinations as to whether any 
species is an endangered or threatened species must be made ``solely on 
the basis of the best scientific and commercial data available.''
    You may submit your information concerning this status review by 
one of the methods listed in the ADDRESSES section. If you submit 
information via https://www.regulations.gov, your entire submission--
including any personal identifying information--will be posted on the 
Web site. If you submit a hardcopy that includes personal identifying 
information, you may request at the top of your document that we 
withhold this personal identifying information from public review. 
However, we cannot guarantee that we will be able to do so. We will 
post all hardcopy submissions on https://www.regulations.gov.
    Information and supporting documentation that we received and used 
in preparing this finding is available for you to review at https://www.regulations.gov, or you may make an appointment during normal 
business hours at the U.S. Fish and Wildlife Service, Nevada Fish and 
Wildlife Office (see FOR FURTHER INFORMATION CONTACT).

Background

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

Petition History

    On January 29, 2010, we received a petition dated January 25, 2010, 
from WildEarth Guardians, requesting that 10 subspecies of Great Basin 
butterflies in Nevada and California be listed as threatened or 
endangered and critical habitat be designated under the Act. The 
petition clearly identified itself as such and included the requisite 
identification information for the petitioner, as required by 50 CFR 
424.14(a). In a March 26, 2010, letter to the petitioner, WildEarth 
Guardians, we responded that we had reviewed the information presented 
in the petition and determined that issuing an emergency regulation 
temporarily listing the 10 subspecies as per section 4(b)(7) of the Act 
was not warranted although this was not requested in the petition. We 
also stated that while we are required to complete a significant number 
of listing and critical habitat actions in Fiscal Year 2010 pursuant to 
court orders, judicially approved settlement agreements, and other 
statutory deadlines, we were able to secure funding in Fiscal Year 2010 
to begin work on the initial finding to determine whether the petition 
provides substantial information indicating that the action may be 
warranted. This finding addresses the petition.

Previous Federal Actions

    On May 22, 1984, we added Mattoni's blue butterfly as Euphilotes 
(=Shijimiaeoides) rita mattonii to our list of candidate species as a 
Category 2 candidate species (49 FR 21664). This subspecies is 
currently known as Euphilotes pallescens mattonii. This subspecies was 
again included in our Category 2 candidate list for November 21, 1991 
(56 FR 58804), at which time we added the remaining nine petitioned 
subspecies as Category 2 candidate species. A Category 2 candidate 
species was a species for which we had information indicating that a 
proposal to list it as threatened or endangered under the Act may be 
appropriate, but for which additional information on biological 
vulnerability and threat was needed to support the preparation of a 
proposed rule. These nine subspecies included the Carson Valley wood 
nymph (Cercyonis pegala ssp.), now known as Cercyonis pegala 
carsonensis. The Baking Powder Flat blue butterfly was added as 
Euphilotes battoides ssp., now known as Euphilotes bernardino minuta. 
The two Railroad Valley skippers, the White River Valley skipper, and 
the Mono Basin skipper were added as Hesperia uncas ssp. and are now 
known as Hesperia uncas fulvapalla,  Hesperia uncas reeseorum, Hesperia 
uncas grandiosa, and Hesperia uncas giulianii, respectively. The 
Steptoe Valley crescentspot was added as Phyciodes pascoensis ssp. and 
is now known as Phyciodes cocyta arenacolor. The bleached sandhill 
skipper was added under a different common name, Denio sandhill skipper 
(Polites sabuleti sinemaculata). The Carson Valley silverspot was added 
as Speyeria nokomis ssp. and is now known as Speyeria nokomis 
carsonensis. All of these subspecies were maintained as Category 2 
candidates in our November 15, 1994 list (59 FR 58982). Please see 
Table 1.

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    Table 1--Petitioned Great Basin Butterflies, With Their Previous and Current Common and Scientific Names
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                                                                  Previous scientific
         Previous common name            Current common name              name           Current scientific name
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Mattoni's blue butterfly.............  Mattoni's blue           Euphilotes               Euphilotes pallescens
                                        butterfly.               (=Shijimiaeoides) rita   mattonii.
                                                                 mattonii.
Carson Valley wood nymph.............  Carson Valley wood       Cercyonis pegala ssp...  Cercyonis pegala
                                        nymph.                                            carsonensis.
Baking Powder Flat blue butterfly....  Baking Powder Flat blue  Euphilotes battoides     Euphilotes bernardino
                                        butterfly.               ssp..                    minuta.
Railroad Valley skipper..............  Railroad Valley skipper  Hesperia uncas ssp.....  Hesperia uncas
                                                                                          fulvapalla.
Railroad Valley skipper..............  Railroad Valley skipper  Hesperia uncas ssp.....  Hesperia uncas
                                                                                          reeseorum.
Railroad Valley skipper/White River    White River Valley       Hesperia uncas ssp.....  Hesperia uncas
 Valley skipper.                        skipper.                                          grandiosa.
Railroad Valley skipper/Mono Basin     Mono Basin skipper.....  Hesperia uncas ssp.....  Hesperia uncas
 skipper.                                                                                 giulianii.
Steptoe Valley crescentspot..........  Steptoe Valley           Phyciodes pascoensis     Phyciodes cocyta
                                        crescentspot.            ssp..                    arenacolor.
Denio sandhill skipper...............  Bleached sandhill        Polites sabuleti         Polites sabuleti
                                        skipper.                 sinemaculata.            sinemaculata.
Carson Valley silverspot.............  Carson Valley            Speyeria nokomis ssp...  Speyeria nokomis
                                        silverspot.                                       carsonensis.
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    In the February 28, 1996, Candidate Notice of Review (CNOR) (61 FR 
7595), we adopted a single category of candidate species defined as 
follows: ``Those species for which the Service has on file sufficient 
information on biological vulnerability and threat(s) to support 
issuance of a proposed rule to list but issuance of the proposed rule 
is precluded.'' In previous CNORs, species meeting this definition were 
known as Category 1 candidates for listing. Thus, the Service no longer 
considered Category 2 species as candidates, including the 10 
petitioned butterfly subspecies, and did not include them in the 1996 
list or any subsequent CNORs. The decision to stop considering Category 
2 species as candidates was designed to reduce confusion about the 
status of these species and to clarify that we no longer regarded these 
species as candidates for listing.

Evaluation of Information for This Finding

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations at 50 CFR 424 set forth the procedures for adding a species 
to, or removing a species from, the Federal Lists of Endangered and 
Threatened Wildlife and Plants. A species may be determined to be an 
endangered or threatened species due to one or more of the five factors 
described in section 4(a)(1) of the Act:
    (a) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (b) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (c) Disease or predation;
    (d) The inadequacy of existing regulatory mechanisms; or
    (e) Other natural or manmade factors affecting its continued 
existence.
    In considering what factors might constitute threats, we must look 
beyond the mere exposure of the species to the factor to determine 
whether the species responds to the factor in a way that causes actual 
impacts to the species. If there is exposure to a factor, but no 
response, or only a positive response, that factor is not a threat. If 
there is exposure and the species responds negatively, the factor may 
be a threat and we then attempt to determine how significant a threat 
it is. If the threat is significant, it may drive or contribute to the 
risk of extinction of the species such that the species may warrant 
listing as threatened or endangered as those terms are defined by the 
Act. This does not necessarily require empirical proof of a threat. The 
combination of exposure and some corroborating evidence of how the 
species is likely impacted could suffice. The mere identification of 
factors that could impact a species negatively may not be sufficient to 
compel a finding that listing may be warranted. The information shall 
contain evidence sufficient to suggest that these factors may be 
operative threats that act on the species to the point that the species 
may meet the definition of threatened or endangered under the Act.
    In making this 90-day finding, we evaluated whether information 
regarding threats to the 10 butterfly subspecies as presented in the 
petition and other information available in our files, is substantial, 
thereby indicating that the petitioned action may be warranted. Our 
evaluation of this information is presented below.

Summary of Common Information on Species

    The 10 butterfly subspecies included in the petition and evaluated 
in this finding are invertebrates endemic to the Great Basin region of 
Nevada and California. All of the petitioned butterflies are from the 
phylum Arthropoda, class Insecta, order Lepidoptera. Taxonomic families 
for the 10 subspecies are: Hesperiidae (5), Nymphalidae (3), and 
Lycaenidae (2). In specific subspecies sections below, we have included 
a short summary of available population and life-history information 
for each subspecies, as provided in the petition, its references, and 
our files.
    The petition provides information regarding the 10 subspecies' 
rankings according to NatureServe (WildEarth Guardians 2010, pp. 3-4). 
The petitioned butterflies are considered at the subspecies taxonomic 
level and all are ranked as critically impaired or impaired at the 
global, national, or State level (WildEarth Guardians 2010, pp. 3-4). 
While the petition states that the ``definitions of `critically 
impaired' and `impaired' are at least equivalent to definitions of 
`endangered' or `threatened' under the [Act],'' this is not an 
appropriate comparison. According to its own Web site, NatureServe's 
assessment of any species ``does not constitute a recommendation by 
NatureServe for listing [that species]'' under the Act (NatureServe 
2010). In addition, NatureServe's assessment procedures include 
``different criteria, evidence requirements, purposes and taxonomic 
coverage [from those of] government lists of endangered and threatened 
species, and therefore these two types of lists should not be expected 
to coincide'' (NatureServe 2010). We found the information related to 
the 10 Great Basin butterflies provided by NatureServe to be limited in 
its usefulness for determining that there is substantial information 
indicating that these species may be warranted for listing under the 
Act.
Summary of Common Threats
    The petition identifies several threats as common to many of the 
petitioned butterfly subspecies using general information applicable to 
most butterfly species: Water development (diversions

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and groundwater pumping), livestock grazing, agriculture, pesticides 
(herbicides and insecticides), inadequate regulatory mechanisms, and 
climate change (WildEarth Guardians 2010, pp. 6-10). In addition, the 
petition claims that all of the subspecies may be biologically 
vulnerable due to limited distribution and small population size or 
numbers of populations (WildEarth Guardians 2010, pp. 6, 10-11). The 
common threats presented in the petition are often associated with 
habitats or general areas that could be suitable for butterfly species, 
but the petition frequently does not associate the threats to actual 
locations known to be occupied by the petitioned subspecies. The 
threats are generally described in the petition, but with little or no 
information on existing or probable impacts to the individual 
petitioned subspecies. We have little to no information available in 
our files to identify potential common threats and connect them to 
existing or probable impacts to the 10 petitioned subspecies. In this 
section, we summarize these common threats to the petitioned subspecies 
as presented in the petition.
    Our conclusion for each subspecies as it relates to each of the 
five factors is based on this summary, in addition to any specific 
threat information provided in the petition or available in our files. 
Our conclusion regarding whether there is substantial scientific or 
commercial information available to indicate that the petitioned action 
is warranted or not is indicated in specific subspecies sections below.
Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of its Habitat or Range
Water Development
    The petition (WildEarth Guardians 2010, p. 6) suggests that the 
historical range for some of the petitioned butterflies has been 
reduced due to loss and mismanagement of riparian and aquatic habitats, 
including springs and seeps, in northern Nevada (Sada et al. 1992, p. 
76; Noss et al. 1995, p. 76; Brussard et al. 1998, pp. 531-532; Sada et 
al. 2001, pp. 11-16; Sada 2008, pp. 49-50), and California (Dahl 1990 
cited by Noss et al. 1995, p. 74).
    The petition claims that water development, such as the large 
groundwater pumping project proposed by the Southern Nevada Water 
Authority (SNWA) in Nevada and western Utah, threatens to lower 
aquifers and will likely reduce or eliminate springs and wetlands and 
their associated habitats (Deacon et al. 2007, p. 689). Proposals by 
SNWA would pump 180,800 acre-feet per year (afy) (223,000,000 cubic-
meters per year (m\3\/year)) of groundwater from southern, central, and 
eastern Nevada to the Las Vegas Valley (Deacon et al. 2007, p. 692). 
Other communities are pursuing rights to an additional 870,487 afy 
(1,073,750,000 m\3\/year) of groundwater (Deacon et al. 2007, p. 693). 
In Nevada, this groundwater pumping proposal could lower water tables 
in some valleys from a few feet to several hundred feet (Schaefer and 
Harrill 1995, p. 1; Myers 2006, p. 75). Models have predicted 
groundwater declines of about 1 to 1,600 feet (ft) (0.3 to 488 meters 
(m)) throughout 78 basins from Utah to California (Deacon et al. 2007, 
p. 692). Pumping is expected to reduce flow of regional springs 2 to 14 
percent in the first 100 years, with continued declines over the next 
100 years (Deacon et al. 2007, p. 692). Groundwater withdrawal can 
result in direct and indirect effects to the water table and is likely 
to impact the discharge amount from seeps and springs (Sanford 2006, p. 
400).
    The petition indicates riparian communities and associated springs, 
seeps, and small streams comprise a small area of the Great Basin and 
Mojave Desert regions, but provide habitat for 70 percent of the 
butterfly species in these regions (Brussard and Austin 1993 cited in 
Brussard et al. 1998, p. 508).
    The petition cites a few instances where habitat loss or 
degradation due to water development has occurred at historical 
locations of the petitioned subspecies, or where it is occurring at 
locations currently known to be occupied. However, the petition more 
typically associates water development with habitat types or general 
areas that may be used by the petitioned subspecies.
    Our files include information regarding groundwater development as 
it relates to perennial yield versus committed water resources within 
some hydrographic basins where petitioned butterflies occur or may 
occur. This file information is from the Nevada Division of Water 
Resources' (NDWR) database (https://water.nv.gov/), which we accessed 
and reviewed on January 12, 2010, saving hard copies of groundwater 
information for various basins in Nevada. Where we discuss perennial 
yield and committed water resources and effects of groundwater 
development within this finding, we are referring to information we 
have reviewed from the NDWR database.
    The Nevada State Engineer (NSE) approves and permits groundwater 
rights in Nevada and defines perennial yield as ``the amount of usable 
water from a ground-water aquifer that can be economically withdrawn 
and consumed each year for an indefinite period of time. It cannot 
exceed the natural recharge to that aquifer and ultimately is limited 
to maximum amount of discharge that can be utilized for beneficial 
use.'' The NSE estimates perennial yield for 256 basins and sub-basins 
(areas) in Nevada, and may ``designate'' a groundwater basin, meaning 
the basin ``is being depleted or is in need of additional 
administration, and in the interest of public welfare, [the NSE may] 
declare preferred uses (such as municipal, domestic) in such basins.'' 
Some of the hydrographic areas in which the petitioned butterflies 
occur are ``designated'' by the NSE and permitted groundwater rights 
approach or exceed the estimated average annual recharge. Such 
commitments of water resources beyond perennial yield may result in 
detrimental impacts to habitats for some of the petitioned subspecies 
in the designated basins. When groundwater extraction exceeds aquifer 
recharge, it may result in surface water level decline, spring drying 
and degradation, or the loss of aquatic habitat (Zektser et al. 2005, 
pp. 396-397).
    Determining whether groundwater development is a threat to springs, 
streams or wetlands or not depends upon: (1) The basins in which 
withdrawals are occurring or proposed exceed perennial yield or have a 
hydrologic connection to springs and groundwater flow systems; (2) 
springs, streams or wetlands are upgradient and outside of the zone of 
influence of the carbonate aquifer (i.e., they occur in the alluvial 
aquifer or mountain block aquifer instead); or (3) springs, streams or 
wetlands are too far away from proposed pumping projects to be impacted 
(Welch et al. 2007, pp. 71-79). Specific information on water 
development impacts pertaining to a particular petitioned subspecies is 
included in specific subspecies sections below as appropriate.
Agriculture
    The petition provides a general discussion of butterfly use of 
agricultural areas. It claims that agricultural practices are 
eliminating suitable habitat, resulting in losses of butterfly species. 
Fleishman et al. (1999, pp. 214-215) is referenced as stating that 
artificial riparian areas such as irrigated croplands support fewer 
butterfly species than native habitats; that most butterfly species 
found in agricultural sites are widespread generalists often found in 
disturbed

[[Page 61536]]

sites; that less common species, as well as those restricted in native 
larval host plants, are less likely to or do not occur in agricultural 
sites, and though agriculture can provide habitat for some butterfly 
species, these modified habitats cannot replace the natural undisturbed 
riparian ecosystems.
    The petition claims that agriculture is a threat to some of the 
petitioned subspecies, but it does not present specific information to 
support the claim that this potential threat is impacting the 
petitioned subspecies, their host plants, or nectar sources, or is 
likely to in the future. The petition does not present information 
regarding which types of agricultural practices may be threats, nor is 
information presented concerning past, present, or projected acreage or 
intensity of these operations in or near occupied or suitable 
locations. The petition also does not report loss of populations or 
reduction in numbers of these butterfly subspecies related directly to 
agricultural practices. We have little to no information in our files 
related to agricultural practices impacting the petitioned subspecies. 
Specific information on agriculture pertaining to a particular 
subspecies is included in specific subspecies sections below as 
appropriate.
Pesticide Use
    The petition claims that pesticide use is a threat to the 
petitioned butterfly subspecies (WildEarth Guardians 2010, p. 7). Use 
of pesticides (including drift) can impact butterfly habitat by killing 
butterfly nectaring and host plant species (Selby 2007, pp. 3, 30). 
This threat can be serious for those species that specialize in one 
host plant species (WildEarth Guardians 2010, p. 7). Use of 
insecticides on pastureland or croplands adjacent to butterfly habitat 
can be a direct threat to butterfly survival (Selby 2007, p. 30).
    The petition does not present any specific supporting information 
that this potential threat may be impacting the subspecies or is likely 
to in the future. The petition does not present specific information 
concerning past, present, or projected intensity of pesticide use in or 
near occupied or suitable locations. The petition does not present 
specific information as to whether this potential threat has, is, or is 
likely to affect the subspecies, their host plants, or nectar sources. 
The petition also does not report loss of populations or reductions in 
numbers of these subspecies to pesticide use. We have no information in 
our files related to pesticide use impacting any of the petitioned 
subspecies or their habitats. Specific information regarding pesticide 
use and impacts to a particular petitioned subspecies is included in 
specific subspecies sections below as appropriate.
Livestock Grazing
    The petition states that livestock grazing in general impacts 
riparian areas, wetlands, seeps, and springs by removing native 
vegetation, and by reducing cover, biomass, and the productivity of 
herbaceous and woody species. It also claims that trampling by 
livestock destroys vegetation and compacts the soil, increasing erosion 
and runoff, and that grazing spreads nonnative plant species (Fleishner 
1994, pp. 631-635; Belsky et al. 1999, pp. 8-11; Sada et al. 2001, p. 
15). Inappropriate livestock grazing can also trample butterfly larvae 
and host or nectar plants, degrade habitats, and assist in the spread 
of nonnative plant species that can dominate or replace native plant 
communities and thereby impact larval host and adult nectar species 
(WildEarth Guardians 2010, pp. 22-23). The petition indicates that 
light or moderate grazing can assist in maintaining butterfly habitats 
(WildEarth Guardians 2010, p. 23), but heavy grazing is considered 
incompatible with the conservation of some butterflies (Sanford 2006, 
p. 401; Selby 2007, pp. 3, 29, 33, 35).
    The petition indicates that the threat from livestock grazing is 
occurring over widespread general habitat areas where the petitioned 
subspecies could be occurring, with a few site-specific instances. The 
petition provides little to no specific supporting information to 
indicate this potential threat may be impacting the petitioned 
subspecies or is likely to in the future. The petition provides little 
to no information related to the level of grazing utilization that has 
or may be occurring at occupied or suitable locations, or that it may 
increase in intensity in the future. The petition does not present 
information that indicates the degree, if any, that invasive plants are 
spreading in the petitioned subspecies' occupied habitats as a result 
of grazing activities. The petition does not report loss of populations 
or reduction in numbers of these petitioned subspecies due to livestock 
grazing. We have little to no information available in our files 
related to livestock grazing impacting the petitioned subspecies. 
Specific information related to livestock grazing and impacts to a 
particular subspecies is included in specific subspecies sections below 
as appropriate.
Climate Change
    The petition claims that climate change in the Great Basin is a 
threat to the petitioned subspecies. The average temperature in the 
Great Basin has increased 0.6 to 1.1 degrees Fahrenheit (0.3 to 0.6 
degrees Celsius) during the last 100 years (Chambers 2008a, p. 29) and 
is expected to increase by 3.6 to 9 degrees Fahrenheit (2 to 5 degrees 
Celsius) over the next century (Cubashi et al. 2001 cited by Chambers 
2008a, p. 29).
    The petition indicates that climate change is expected to affect 
the timing and flow of streams, springs, and seeps in the Great Basin 
(Chambers 2008b, p. 20) which support the moist meadows upon which some 
petitioned butterflies depend (WildEarth Guardians 2010, p. 9). Earlier 
spring snowmelt appears to be affecting the date of blooming for some 
plants in the Great Basin (Chambers 2008a, p. 29). Potential changes in 
the bloom date of meadow plants used by butterflies due to climate 
change could affect their use (WildEarth Guardians 2010, p. 9). The 
petition indicates that drought in the Great Basin could negatively 
affect riparian habitats, moist meadows, and similar habitats, 
especially those already stressed by other factors (Major 1963 cited by 
West 1983, p. 344). As climate changes, droughts may become more common 
in the Great Basin (Chambers et al. 2008, p. 3) and American Southwest 
(Seager et al. 2007, pp. 1181-1183), modifying future precipitation 
(WildEarth Guardians 2010, p. 8). Increased carbon dioxide 
(CO2) may favor invasion of annual grasses such as the 
nonnative Bromus tectorum (cheat grass) (Smith et al. 2000, pp. 79, 
81). Increased temperatures and CO2 levels have various 
effects on plant growth and chemistry, which may affect insect 
abundance and persistence (Stiling 2003, pp. 486-488). Increasing 
temperatures can also affect insect development and reproduction 
(Sehnal et al. 2003, pp. 1117-1118).
    According to Loarie et al. (2009, p. 1052), as referenced in the 
petition, species and ecosystems will need to shift northward an 
average of 0.3 mile (mi) (0.42 kilometer (km)) per year to avoid the 
effects of increasing temperatures associated with climate change. 
Loarie et al. (2009, p. 1053) also states that distances may be greater 
for species in deserts and xeric (dry habitat) shrublands, where 
climate change is predicted to have greater effect than in some other 
ecosystems. The petition states that it is unlikely that small, 
isolated populations of butterflies in the Great Basin, dependent on 
reduced

[[Page 61537]]

habitats, will be able to shift to other habitats in the face of 
climate change (WildEarth Guardians 2010, p. 9). Many species in the 
Great Basin have specialized habitat requirements and limited mobility, 
which influence their ability to adapt to anthropogenic environmental 
change (Fleishman 2008, p. 61). Species and habitats already stressed 
by other factors may be less able to cope with climate change 
(WildEarth Guardians 2010, p. 10). The petition did not provide climate 
change or drought information specific to Nevada or California, or the 
general areas known to be occupied by any of the 10 petitioned 
butterflies, or on the specific detrimental effects of climate change 
or drought to each subspecies.
    Based on information in our files, recent projections of climate 
change in the Great Basin over the next century include: Increased 
temperatures, with an increased frequency of extremely hot days in 
summer; more variable weather patterns and more severe storms; more 
winter precipitation in the form of rain, with potentially little 
change or decreases in summer precipitation; and earlier, more rapid 
snowmelt (United States Environmental Protection Agency 1998, pp. 1-4; 
Chambers and Pellant 2008, pp. 29-33).
    It is difficult to predict local climate change impacts, due to 
substantial uncertainty in trends of hydrological variables, 
limitations in spatial and temporal coverage of monitoring networks, 
and differences in the spatial scales of global climate models and 
hydrological models (Bates et al. 2008, p. 3). Thus, while the 
information in the petition and our files indicates that climate change 
has the potential to affect vegetation and habitats used by butterflies 
in the Great Basin in the long term, there is much uncertainty 
regarding which habitat attributes could be affected, and the timing, 
magnitude, and rate of their change as it relates to the 10 petitioned 
butterflies. Specific information pertaining to climate change and a 
particular petitioned subspecies is included in specific subspecies 
sections below as appropriate.
Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes
    The petition states that individuals of all of the petitioned 
butterfly subspecies have been collected by scientists and amateur 
collectors over the years, but it is not known whether collection is a 
threat to any of the subspecies as a whole (WildEarth Guardians 2010, 
p. 8). The petition does not provide information that overutilization 
has led to the loss of butterfly populations or a significant reduction 
in numbers of individuals for any of the petitioned butterflies.
    We do not have information in our files to suggest overutilization 
as a threat to any of the petitioned subspecies. This discussion 
provides the basis for our determinations in specific subspecies 
sections below.
Factor C. Disease or Predation
    The petition indicates that disease is not known to be a threat to 
any of the petitioned butterflies (WildEarth Guardians 2010, p. 8). A 
general statement is made in the petition that larvae and adult 
butterflies are subject to predation from a variety of wildlife; 
however, it is not known whether predation is a threat to any of the 
petitioned subspecies (WildEarth Guardians 2010, p. 8).
    We do not have information in our files suggesting disease or 
predation as a threat to the petitioned butterfly subspecies. This 
discussion provides the basis for our determinations in specific 
subspecies sections below.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
    The petition considers the inadequacy of existing regulatory 
mechanisms to be a threat for all 10 petitioned subspecies (WildEarth 
Guardians 2010, p. 40). The petition claims that no Federal or State 
programs exist to manage sensitive invertebrate species in Nevada or 
the Great Basin, but it does not address existing regulatory mechanisms 
in California (WildEarth Guardians 2010, p. 8). Information provided in 
the petition's referenced material suggests that the general habitats 
that could be used by the petitioned subspecies may occur on lands 
under various combinations of private, State, tribal, and Federal 
management. The petition presents little to no specific information to 
support the claim that potential threats are associated with inadequate 
existing regulatory mechanisms, nor does the petition connect 
inadequate existing regulatory mechanisms by Bureau of Land Management 
(BLM) or other Federal agencies to impacts to or losses of populations 
or declining population trends of the petitioned subspecies.
    All of the petitioned butterfly subspecies, with the exception of 
the Carson Valley wood nymph and Railroad Valley skipper (Hesperia 
uncas reeseorum), are included under the referenced 2007 BLM list of 
sensitive species (BLM 2007a, pp. J6-J7, J37). In 2008, BLM policy and 
guidance for species of concern occurring on BLM-managed land was 
updated under BLM's 6840 Manual, ``Special Status Species Management'' 
(BLM 2008a). This manual provides agency policy and guidance for the 
conservation of special status plants and animals and the ecosystems on 
which they depend, but it is not a regulatory document. The objectives 
for BLM special status species are ``to conserve and/or recover ESA-
listed species and the ecosystems on which they depend so that ESA 
protections are no longer needed for these species and to initiate 
proactive conservation measures that reduce or eliminate threats to 
Bureau sensitive species to minimize the likelihood of and need for 
listing of these species under the ESA'' (BLM 2008a, p. 3). Inclusion 
as a BLM sensitive species does provide consideration of conservation 
measures for the subspecies under the National Environmental Policy 
Act.
    Based on information presented in the petition and available in our 
files, Nevada does not have the ability to protect invertebrates under 
its current State law. The Nevada Department of Wildlife is limited in 
its ability to protect insects under its current regulations (Nevada 
Revised Statutes (NRS)). Nevada State law protects species that the 
Wildlife Commission determines to be imperiled (NRS 503.585 cited in 
WildEarth Guardians 2010, p. 8). While some invertebrates such as 
mollusks and crustaceans may be protected because they can be 
classified under wildlife (NRS 501.110 cited in WildEarth Guardians 
2010, p. 8), butterflies are not covered under this statute (WildEarth 
Guardians 2010, p. 8). No butterfly species are currently protected by 
State law in Nevada (Nevada Administrative Code 503.020-503.080). The 
California Department of Fish and Game is unable to protect insects 
under its current regulations (P. Bontadelli, in litt., 1990).
    The petition presents little to no specific information supporting 
the claim that threats are associated with inadequate existing 
regulatory mechanisms. Additionally, the petition provides little to no 
specific supporting information to associate losses of butterfly 
populations or declining population trends to inadequate existing 
regulatory mechanisms by State wildlife agencies or other State 
agencies.
    We have little to no information available in our files to suggest 
that inadequacy of existing regulatory mechanisms may be threatening 
the petitioned subspecies. For most of these subspecies, we have no 
information in our files related to this potential threat; however, for 
a few there is some

[[Page 61538]]

information in our files to suggest a potential threat due to the 
inadequacy of existing regulatory mechanisms. Specific information 
pertaining to the inadequacy of existing regulatory mechanisms and a 
particular subspecies is included in specific subspecies sections below 
as appropriate.
Factor E. Other Natural or Manmade Factors Affecting its Continued 
Existence
    The petition states that all of the petitioned butterflies may be 
susceptible to the effects of biological vulnerability, which may 
increase the likelihood of extinction (WildEarth Guardians 2010, pp. 6, 
10). Characteristic butterfly population fluctuations and short 
generation times, combined with small populations, can influence 
genetic diversity and long-term persistence (Britten et al. 2003, pp. 
229, 233). The petition further asserts that many of the butterflies 
included in the petition occur as single populations or a few disparate 
ones, and that the number of populations may be more important than 
population size when assessing the status of a butterfly (Sanford 2006, 
p. 401). Some of the petitioned butterflies occur in isolated 
populations in patchy environments (WildEarth Guardians 2010, p. 11), 
and the lack of dispersal corridors or resistance to barriers to 
dispersal may inhibit gene flow between populations and increase the 
likelihood of extinction (Wilcox and Murphy 1985, pp. 882-883). 
Overall, the petition provides little information related to the 
distribution, numbers of populations, size of populations, or 
population trends for the 10 petitioned butterfly subspecies. However, 
the petition and its references indicate that most of the 10 subspecies 
are known to have more than one population. The petition provides 
little to no specific information that indicates that biological 
vulnerability may be a threat to any of the petitioned subspecies.
    General biological information in our files indicates that the 
combination of few populations, small ranges, and restricted habitats 
can make a species susceptible to extinction or extirpation from 
portions of its range due to random events such as fire, drought, 
disease, or other occurrences (Shaffer 1987, pp. 71-74; Meffe and 
Carroll 1994, pp. 190-197). Limited distribution and small population 
numbers or sizes are considered in determining whether the petition 
provides substantial information regarding a natural or anthropogenic 
threat, or a combination of threats, that may be affecting a particular 
subspecies. However, in the absence of information identifying chance 
events, other threats, the potential for such chance events to occur in 
occupied habitats, and connecting these threats to a restricted 
geographic range of a subspecies, we do not consider chance events, 
restricted geographic range, or rarity by themselves to be threats to a 
subspecies. In addition, butterfly populations are highly dynamic and 
from year to year, butterfly distributions can be highly variable 
(Weiss et al. 1997, p. 2), and desert species seem prone to dramatic 
fluctuations in number (Scott 1986, p. 109).
    We have little to no additional information related to the overall 
abundance, distribution, number and size of populations, or population 
trends for any of the 10 subspecies in our files. We do not have 
additional information in our files related to biological vulnerability 
as a threat to any of the petitioned butterfly subspecies. Specific 
information pertaining to biological vulnerability and a particular 
subspecies is included in specific subspecies sections below as 
appropriate.

Species for Which Substantial Information Was Not Presented

    In this section, the butterfly subspecies are listed in 
alphabetical order by their common name.
Carson Valley silverspot (Speyeria nokomis carsonensis)
    We accept the characterization of the Carson Valley silverspot as a 
valid subspecies based on its description by Austin (1998c, pp. 573-
574). The Carson Valley silverspot's larval host plant is the violet, 
Viola nephrophylla (Austin et al. 2000, p. 2; Austin and Leary 2008, p. 
97), and the primary nectar sources are Cirsium sp. (Austin et al. 
2000, p. 2). A single brood flies during mid-July to mid-October 
(Austin 1998c, p. 574; Austin et al. 2000, p. 2).
    The Carson Valley silverspot occurs in wet meadows along the east 
side of the Carson Range from southern Washoe County, Nevada, south to 
northern Alpine County, California. It occurs along the Carson River 
drainage in Douglas County, Nevada, and Alpine County, California. It 
also occurs in the Pine Nut Mountains of Douglas County, Nevada, and 
the Sweetwater Mountains (Austin 1998c, p. 574; Austin et al. 2000, p. 
2; The Nature Conservancy 2009, p. 1), Pine Grove Hills, and Smith 
Valley of Lyon County, Nevada (Austin and Leary 2008, p. 97). 
Populations have been found along the Walker River drainage in Mono 
County, California (Austin et al. 2000, p. 2; The Nature Conservancy 
2009, p. 1). The largest known colony occurs at Scossa Ranch, Douglas 
County, Nevada (Austin et al. 2000, p. 2). The subspecies has been 
documented from the Carson Range North, Washoe County; Snow Valley, 
Carson City County; and Mineral Valley, Pine Nut Creek, and Sugar Loaf, 
Douglas County (NNHP 2006, pp. 21-22, 36-37). The petition indicates 
there are 13 Nevada occurrences in the NNHP (NNHP 2009, p. 8) database, 
but location information is not indicated. However, review of the 
complete Nevada database, which we have in our files, includes 
additional locations at Davis Creek Park, Kingsbury Grade, Thompson 
Canyon, Dangberg Reservoir near Gardnerville, Daggett Pass, Veceey 
Canyon area, Haines Canyon, Thomas Creek, and Kings Canyon (NNHPD 
2008). The petition notes that this subspecies may currently occur at 
37 sites (M. Sanford, pers. comm., cited in WildEarth Guardians 2010, 
p. 18), but location information was not provided. The petition states 
that the subspecies is reduced from historical abundance (M. Sanford 
pers. comm., cited in WildEarth Guardians 2010, p. 17).

    Factor A:
Information Provided in the Petition
    The petition asserts that water development; land development; 
agriculture; livestock grazing; nonnative plant species invasion, such 
as by Lepidium latifolium (tall whitetop); and pesticide use may impact 
this subspecies (WildEarth Guardians 2010, p. 19). The petition 
indicates that these types of activities can eliminate, degrade, and 
fragment butterfly habitat (WildEarth Guardians 2010, p. 19). The 
petition adds that heavy livestock grazing on public and private land 
in the Sierra Nevada, Pine Nut Mountains, and Sweetwater Mountains has 
degraded habitat for the Carson Valley silverspot (WildEarth Guardians 
2010, p. 20). The annual grazing removes vegetation from seep- and 
spring-fed meadows, and water diversions for grazing have dried up 
meadows, eliminating silverspot habitat (WildEarth Guardians 2010, p. 
20). The petition mentions that climate change may result in the drying 
out of moist habitats in the Carson Valley (WildEarth Guardians 2010, 
p. 20).
    According to the petition, most of the Carson Valley silverspot 
populations occur in habitats associated with the Carson River and its 
tributaries in ``Carson Valley'' (WildEarth Guardians 2010, p. 18). The 
petition indicates that the NNHP has ranked the Carson River among the 
26 highest priority wetland areas in the State (NNHP 2007, p. 8).

[[Page 61539]]

Many other associated areas, including tributaries, riparian areas, wet 
meadows, marshes, ponds, and ephemeral pools in Carson Valley, Nevada, 
are also listed (NNHP 2007, pp. 12-14). According to NNHP (2007, p. 36) 
and The Nature Conservancy (2008, p. 31), numerous areas associated 
with these sites and others along the Middle Carson River have been 
degraded or converted to other lands uses. Moderate to high stressors 
impacting these areas in Carson Valley include water development and 
diversions, groundwater pumping, hydrogeomorphic modification, land 
development, agriculture, livestock grazing, recreation, fire 
suppression, wetland leveling, and nonnative species invasions. The 
petition implies these activities are negatively impacting the Carson 
Valley silverspot.
Evaluation of Information Provided in the Petition and Our Files
    The petition does not provide specific, supporting information to 
indicate that the Carson Valley silverspot may be impacted from water 
development, land development, agriculture, livestock grazing, 
nonnative plant species invasion, pesticide use, or climate change at 
occupied locations in Nevada or California. The petition does not 
provide additional information or discussion regarding possible impacts 
to the Carson Valley silverspot from recreation, fire suppression, and 
wetland leveling. The petition does not provide specific, supporting 
information regarding past, present, or future conditions of these 
threats or their scope, immediacy, or intensity at occupied or suitable 
habitats in Nevada or California. The petition emphasizes habitat 
impacts along the Middle Carson River in Nevada; however, there are a 
number of populations located in several counties in both Nevada and 
California. Little to no information regarding habitat impacts to these 
additional populations is indicated. We have information in our files 
that indicate habitat disturbances such as water table changes may 
adversely impact larval food availability (Austin et al. 2000, p. 2), 
but details are not provided. Grazing has been associated with 
population declines (M. Sanford, pers. comm., cited in WildEarth 
Guardians 2010, p. 19), but details are not provided. We do not have 
any further specific, supporting information in our files regarding 
potential threats or resulting negative impacts to Carson Valley 
silverspot populations in Nevada or California. Also see the ``Summary 
of Common Threats'' section for information pertaining to water 
development, agriculture, livestock grazing, pesticide use, and climate 
change as potential threats.
    While the petition reports losses of Carson Valley silverspot 
populations from their historical abundance (M. Sanford, pers. comm., 
cited in WildEarth Guardians 2010, p. 17), which could suggest a 
negative response to these potential threats, details regarding these 
losses and the reason(s) for them are not provided. The petition does 
not present specific information related to population numbers, size, 
or trends for the Carson Valley silverspot over any period of time. The 
petition does not provide additional information related to the 
reported population declines, regarding their locations, number of 
populations, or magnitude of them. We do not have this information in 
our files. As a result, it is not possible to put these reported 
declines into context to determine whether populations of the Carson 
Valley silverspot may be experiencing declines or not or their possible 
severity. These declines might be attributed to the normal natural 
fluctuations of butterfly populations. Butterfly populations are highly 
dynamic and numbers and distribution can be highly variable year to 
year (Weiss et al. 1997, p. 2).
    Based on our evaluation of the information provided in the petition 
and in our files, we have determined that the petition does not present 
substantial information to indicate that listing the Carson Valley 
silverspot may be warranted due to the present or threatened 
destruction, modification, or curtailment of its habitat or range.

    Factors B and C:
Information Provided in the Petition
    The petition states that it is unknown whether overutilization, 
disease, or predation are threats to this subspecies (WildEarth 
Guardians 2010, p. 8). Based on information referenced in the petition, 
numerous individuals (432 males, 224 females) of this subspecies have 
been collected by several collectors between 1964 and 1989 at Scossa 
Ranch, Douglas County, Nevada (Austin 1998c, p. 574). Based on these 
total numbers over the 25-year time period, an average of 17 males and 
9 females were collected per year. Ranges of individuals collected 
during a single day in a particular year were 1 to 39 for males and 1 
to 54 for females. In some years, multiple collections occurred, and in 
some years collections occurred on consecutive days (Austin 1998c, p. 
574).
Evaluation of Information Provided in the Petition and Our Files
    The petition does not provide information that overutilization, 
disease, or predation has negatively impacted the subspecies. We have 
no information in our files related to overutilization, disease, or 
predation for this subspecies. According to Austin et al. (2000, p. 2), 
Scossa Ranch remains the largest known colony for this subspecies. As 
indicated earlier, there are also multiple populations of this 
subspecies occurring elsewhere in Nevada and California. We do not know 
if or to what extent these other populations have been impacted by 
collection efforts. The available information does not indicate 
collection efforts are negatively impacting the Carson Valley 
silverspot. Also see the ``Summary of Common Threats'' section for 
information pertaining to overutilization, disease, and predation as 
potential threats.
    Based on our evaluation of the information provided in the petition 
and in our files, we have determined that the petition does not present 
substantial information to indicate that listing the Carson Valley 
silverspot may be warranted due to Factor B (overutilization for 
commercial, recreational, scientific, or educational purposes) or 
Factor C (disease or predation).

    Factor D:
Information Provided in the Petition
    The petition asserts that inadequate existing regulatory mechanisms 
are a threat to this subspecies (WildEarth Guardians 2010, pp. 8, 40). 
This butterfly is listed as a BLM sensitive species (BLM 2007a, p. J6). 
This designation can offer it some conservation consideration. The 
petition also indicates that some populations of the Carson Valley 
silverspot, as well as potential habitat, occur on properties covered 
by conservation easements (WildEarth Guardians 2010, p. 19). These 
easements may be protected from land development, but they are not 
protected from other activities such as groundwater pumping, invasive 
species, livestock grazing, and agricultural use (WildEarth Guardians 
2010, p. 19).
Evaluation of Information in the Petition and Our Files
    The petition does not provide specific information to support the 
assertion that existing regulatory mechanisms are inadequate to protect 
the subspecies from potential threats because it does not provide 
substantial information to support their assertion that threats are

[[Page 61540]]

occurring under the other factors. The petition does not connect 
inadequate existing regulatory mechanisms to losses of Carson Valley 
silverspot populations or declining population trends. We do not have 
information in our files related to the inadequacy of existing 
regulatory mechanisms for this subspecies. Also see the ``Summary of 
Common Threats'' section for information pertaining to the inadequacy 
of regulatory mechanisms as a potential threat.
    Based on our evaluation of the information provided in the petition 
and in our files, we have determined that the petition does not present 
substantial information to indicate that listing the Carson Valley 
silverspot may be warranted due to the inadequacy of existing 
regulatory mechanisms.

    Factor E:
Information Provided in the Petition
    The petition indicates that this subspecies may be vulnerable to 
reduced population numbers (WildEarth Guardians 2010, p. 40) due to the 
observed subspecies' reduction in numbers from historical abundance (M. 
Sanford pers. comm., cited in WildEarth Guardians 2010, p. 17).
Evaluation of Information in the Petition and Our Files
    The petition did not present, nor do we have, specific information 
in our files related to population numbers, size, or trends for the 
Carson Valley silverspot. The petition does not provide additional 
information related to the reported population declines, regarding the 
location, number of populations, magnitude of declines, or reasons for 
them. The petition does not provide information on chance events or 
other threats to the subspecies and connect them to small population 
numbers or size, or the potential for such threats to occur in occupied 
habitats in the future. Since this subspecies is distributed over a 
number of populations in two States, its extinction vulnerability due 
to stochastic events may be reduced. In the absence of specific 
information and connection, we do not consider small population numbers 
alone to be a threat to this subspecies. Also see the ``Summary of 
Common Threats'' section for information pertaining to small population 
size as a potential threat.
    Based on evaluation of the information provided in the petition and 
our files, we have determined that the petition does not present 
substantial information to indicate that listing the Carson Valley 
silverspot may be warranted due to other natural or manmade factors 
affecting the subspecies' continued existence.
Carson Valley Wood Nymph (Cercyonis pegala carsonensis)
    We accept the characterization of the Carson Valley wood nymph as a 
valid subspecies, based on its description by Austin (1992, pp. 10-11). 
The larval host plant is a grass or sedge species (Austin et al. 2000, 
p. 1). Adults nectar on a variety of white and yellow flowers from the 
families Apiaceae (carrot) and the Asteraceae (sunflower) (Austin 1992, 
p. 11). The single brood flies from early July to early September 
(Austin 1992, p. 11).
    The Carson Valley wood nymph occurs in marshes of the western Great 
Basin along the base of the Carson Range, especially in Carson Valley 
from Carson City, Nevada, south to east-central Alpine County, 
California, and the Gardnerville area of Douglas County, Nevada, with a 
few northern specimens from the Reno area, Washoe County, Nevada 
(Austin 1992, p. 11). Austin et al. (2000, p. 1) mention unidentified 
localities in Lyon County, Nevada. The petition indicates there are 14 
Nevada occurrences recorded in the NNHP database, but occurrence 
locations are not identified (NNHP 2009, p. 6). However, review of the 
complete Nevada database, which we have in our files, shows additional 
locations near Minden, Daggett Pass, Centerville, Genoa, and along the 
Carson River, with Cradlebaugh Bridge being a named location (NNHPD 
2008). The largest colony occurs at Scossa Ranch, Douglas County 
(Austin et al. 2000, p. 1). According to the petition, populations 
appear to be declining between 10 to 30 percent in the short term with 
possible extirpation of populations in Washoe County (NatureServe 
2009c, p. 2). Surveys conducted between 2001 and 2006 showed that some 
populations of the Carson Valley wood nymph have been extirpated (M. 
Sanford, pers. comm., cited in WildEarth Guardians 2010, p. 22).

    Factor A:
Information Provided in the Petition
    The petition asserts in general that water development; land 
development; agriculture; livestock grazing; invasion by nonnative 
pl