Federal Register / Vol. 76, No. 71 / Wednesday, April 13, 2011 / Proposed Rules 20613 

however, the Agency seeks to maximize 

the opportunity for public participation 

on harassment by inviting further 

comment during the open EOBR 2 

rulemaking. 

By notice published on March 10, 

2011 (76 FR 13121), the Agency has 

already extended the public comment 

period for the EOBR 2 NPRM to May 23, 

2011. The Agency encourages interested 

parties to take advantage of this 

extended comment period to submit 

comment on the issues set forth in this 

notice. As indicated in the March 10 

extension notice, the Agency will also 

accept and consider comments on all 

issues within the scope of the NPRM. 

Request for Comments: FMCSA 

encourages all interested parties to 

submit comments, including supporting 

data, information or examples, regarding 

the use of EOBRs for purposes of driver 

harassment. In particular, the Agency 

encourages commenters to address the 

following: 

• Experiences drivers have had 

regarding harassment, including 

coercion by carriers to evade the HOS 

regulations; 

• Whether such carrier activity would 

be permitted as productivity monitoring 

or would be barred by other statutory or 

regulatory provisions; 

• Whether use of EOBRs would 

impact the ability of carriers, shippers, 

and other parties to harass or coerce 

drivers to violate HOS requirements; 

• The effectiveness of mechanisms 

currently available under 49 CFR 392.3, 

49 CFR part 395 and 49 U.S.C. 31105(a) 

to protect against carrier coercion; and 

• Whether additional regulations or 

guidance from FMCSA are necessary to 

ensure EOBR devices are not used to 

harass vehicle operators. 

Issued on: April 7, 2011. 

Anne S. Ferro, 

Administrator. 

[FR Doc. 2011–8789 Filed 4–12–11; 8:45 am] 

BILLING CODE 4910–EX–P 

DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

50 CFR Part 17 

[Docket No. FWS–R8–ES–2010–0077; MO 

92210–0–0008] 

Endangered and Threatened Wildlife 

and Plants; 90-Day Finding on a 

Petition To List Spring Mountains 

Acastus Checkerspot Butterfly as 

Endangered 

AGENCY: Fish and Wildlife Service, 

Interior. 

ACTION: Notice of 90-day petition 

finding. 

SUMMARY: We, the U.S. Fish and 

Wildlife Service, announce a 90-day 

finding on a petition to list the Spring 

Mountains acastus checkerspot butterfly 

(Chlosyne acastus robusta) as 

endangered under the Endangered 

Species Act of 1973, as amended (Act). 

Based on our review, we find that the 

petition presents substantial scientific 

or commercial information indicating 

that listing the Spring Mountains 

acastus checkerspot butterfly as 

endangered or threatened may be 

warranted. Therefore, with the 

publication of this notice, we are 

initiating a review of the status of the 

species to determine if listing the Spring 

Mountains acastus checkerspot butterfly 

as endangered or threatened is 

warranted. To ensure that this status 

review is comprehensive, we are 

requesting scientific and commercial 

data and other information regarding 

this subspecies. Based on the status 

review, we will issue a 12-month 

finding on the petition, which will 

address whether the petitioned action is 

warranted, as provided in section 

4(b)(3)(B) of the Act. 

DATES: To allow us adequate time to 

conduct this review, we request that we 

receive information on or before June 

13, 2011. Please note that if you are 

using the Federal eRulemaking Portal 

(see ADDRESSES section below), the 

deadline for submitting an electronic 

comment is Eastern Standard Time on 

this date. After June 13, 2011, you must 

submit information directly to the 

Nevada Fish and Wildlife Office (see 

FOR FURTHER INFORMATION CONTACT

section below). Please note that we 

might not be able to address or 

incorporate information that we receive 

after the above requested date. 

ADDRESSES: You may submit 

information by one of the following 

methods: 

• Electronically: Go to the Federal 

eRulemaking Portal: http:// 

www.regulations.gov. In the Keyword 

box, enter Docket No. FWS–R8–ES– 

2010–0077, which is the docket number 

for this rulemaking. Then, in the Search 

panel on the left side of the screen, 

under the Document Type heading, 

click on the Proposed Rules link to 

locate this document. You may submit 

a comment by clicking on ‘‘Send a 

Comment or Submission.’’ 

• By hard copy: Submit by U.S. mail 

or hand-delivery to: Public Comments 

Processing, Attn: FWS–R8–ES–2010– 

0077; Division of Policy and Directives 

Management; U.S. Fish and Wildlife 

Service; 4401 N. Fairfax Drive, MS 

2042–PDM; Arlington, VA 22203. 

We will post all information we 

receive on http://www.regulations.gov. 

This generally means that we will post 

any personal information you provide 

us (see the Request for Information 

section below for more details). 

FOR FURTHER INFORMATION CONTACT: Jill 

Ralston, Deputy State Supervisor, U.S. 

Fish and Wildlife Service, Nevada Fish 

and Wildlife Office, 4701 North Torrey 

Pines Drive, Las Vegas, NV 89130; by 

telephone 702–515–5230; or by 

facsimile to 702–515–5231. If you use a 

telecommunications device for the deaf 

(TDD), please call the Federal 

Information Relay Service (FIRS) at 

800–877–8339. 

SUPPLEMENTARY INFORMATION: 

Request for Information 

When we make a finding that a 

petition presents substantial 

information indicating that listing a 

species may be warranted, we are 

required to promptly review the status 

of the species (status review). For the 

status review to be complete and based 

on the best available scientific and 

commercial information, we request 

information on the Spring Mountains 

acastus checkerspot butterfly from 

governmental agencies, Native 

American Tribes, the scientific 

community, industry, and any other 

interested parties. We seek information 

on: 

(1) The subspecies’ biology, range, 

and population trends, including: 

(a) Habitat requirements for feeding, 

breeding, and sheltering; 

(b) Genetics and taxonomy; 

(c) Historical and current range, 

including distribution patterns; 

(d) Historical and current population 

levels, and current and projected trends; 

and 

(e) Past and ongoing conservation 

measures for the subspecies, its habitat, 

or both. 

(2) The factors that are the basis for 

making a listing/delisting/downlisting 

determination for a species under 

section 4(a) of the Endangered Species 

Act of 1973, as amended (Act) 

(16 U.S.C. 1531 et seq.), which are: 

(a) The present or threatened 

destruction, modification, or 

curtailment of its habitat or range; 

(b) Overutilization for commercial, 

recreational, scientific, or educational 

purposes; 

(c) Disease or predation; 

(d) The inadequacy of existing 

regulatory mechanisms; or 

(e) Other natural or manmade factors 

affecting its continued existence. 


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20614 Federal Register / Vol. 76, No. 71 / Wednesday, April 13, 2011 / Proposed Rules 

If, after the status review, we 

determine that listing the Spring 

Mountains acastus checkerspot butterfly 

is warranted, we will propose critical 

habitat (see definition in section 3(5)(A) 

of the Act), under section 4 of the Act, 

to the maximum extent prudent and 

determinable at the time we propose to 

list the subspecies. Therefore, within 

the geographical range currently 

occupied by the Spring Mountains 

acastus checkerspot butterfly, we 

request data and information on: 

(1) What may constitute ‘‘physical or 

biological features essential to the 

conservation of the species’’; 

(2) Where these features are currently 

found; and 

(3) Whether any of these features may 

require special management 

considerations or protection. 

In addition, we request data and 

information on ‘‘specific areas outside 

the geographical area occupied by the 

species’’ that are ‘‘essential to the 

conservation of the species.’’ Please 

provide specific comments and 

information as to what, if any, critical 

habitat you think we should propose for 

designation if the subspecies is 

proposed for listing, and why such 

habitat meets the requirements of 

section 4 of the Act. 

Please include sufficient information 

with your submission (such as scientific 

journal articles or other publications) to 

allow us to verify any scientific or 

commercial information you include. 

Submissions merely stating support 

for or opposition to the action under 

consideration without providing 

supporting information, although noted, 

will not be considered in making a 

determination. Section 4(b)(1)(A) of the 

Act directs that determinations as to 

whether any species is an endangered or 

threatened species must be made ‘‘solely 

on the basis of the best scientific and 

commercial data available.’’ 

You may submit your information 

concerning this status review by one of 

the methods listed in the ADDRESSES

section. We will not accept comments 

sent by e-mail or fax or to an address not 

listed in the ADDRESSES section of this 

document. If you submit information via 

http://www.regulations.gov, your entire 

submission—including any personal 

identifying information—will be posted 

on the Web site. If you submit a 

hardcopy that includes personal 

identifying information, you may 

request at the top of your document that 

we withhold this personal identifying 

information from public review. 

However, we cannot guarantee that we 

will be able to do so. We will post all 

hardcopy submissions on http:// 

www.regulations.gov. 

Information and supporting 

documentation that we received and 

used in preparing this finding is 

available for you to review at http:// 

www.regulations.gov, or you may make 

an appointment during normal business 

hours at the U.S. Fish and Wildlife 

Service, Nevada Fish and Wildlife 

Office (see FOR FURTHER INFORMATION

CONTACT). 

Background 

Section 4(b)(3)(A) of the Act requires 

that we make a finding on whether a 

petition to list, delist, or reclassify a 

species presents substantial scientific or 

commercial information indicating that 

the petitioned action may be warranted. 

We are to base this finding on 

information provided in the petition, 

supporting information submitted with 

the petition, and information otherwise 

available in our files. To the maximum 

extent practicable, we are to make this 

finding within 90 days of our receipt of 

the petition, and publish our notice of 

the finding promptly in the Federal 

Register. 

Our standard for substantial scientific 

or commercial information within the 

Code of Federal Regulations (CFR) with 

regard to a 90-day petition finding is 

‘‘that amount of information that would 

lead a reasonable person to believe that 

the measure proposed in the petition 

may be warranted’’ (50 CFR 424.14(b)). 

If we find that substantial scientific or 

commercial information was presented, 

we are required to promptly conduct a 

species status review, which we 

subsequently summarize in our 12- 

month finding. 

Petition History 

On September 18, 2009, we received 

a petition, dated September 16, 2009, 

from Bruce M. Boyd, requesting that the 

Spring Mountains acastus checkerspot 

butterfly be listed as endangered under 

the Act (Boyd 2009). The petition 

clearly identified itself as such and 

included the requisite identification 

information for the petitioner, as 

required by 50 CFR 424.14(a). In a 

November 24, 2009, letter to petitioner 

Bruce M. Boyd, we responded that we 

reviewed the information presented in 

the petition and determined that issuing 

an emergency regulation temporarily 

listing the butterfly under section 4(b)(7) 

of the Act was not warranted (Service 

2009, p. 1). We also stated that funding 

was secured and that we anticipated 

making an initial finding in Fiscal Year 

2010 as to whether the petition contains 

substantial information indicating that 

the action may be warranted. This 

finding addresses the petition. 

Previous Federal Actions 

In 1991 and 1994, the U.S. Fish and 

Wildlife Service (Service) included the 

Spring Mountains acastus checkerspot 

butterfly in a compilation of taxa that 

were to be reviewed for possible 

addition to the Lists of Endangered and 

Threatened Wildlife and Plants (56 FR 

58804, November 21, 1991; 59 FR 

58982, November 15, 1994). In both 

years the Spring Mountains acastus 

checkerspot butterfly was assigned to a 

‘‘Category 2’’ species. Such a designation 

indicated that proposing to list was 

possibly appropriate, but additional 

information on biological vulnerability 

and threats were needed to support the 

preparation of a proposed rule. The 

trend for Spring Mountains acastus 

checkerspot butterfly was described as 

‘‘Unknown.’’ These notices stressed that 

species in this category were not 

proposed for listing, nor were there any 

plans to list unless supporting 

information became available. 

In the February 28, 1996, Candidate 

Notice of Review (61 FR 7595), we 

adopted a single category of candidate 

species defined as follows: ‘‘Those 

species for which the Service has on file 

sufficient information on biological 

vulnerability and threat(s) to support 

issuance of a proposed rule to list but 

issuance of the proposed rule is 

precluded.’’ In previous Candidate 

Notices of Review, species matching 

this definition were known as Category 

1 candidates for listing. Thus, the 

Service no longer considered Category 2 

species as candidates and did not 

include them in the 1996 or any 

subsequent Candidate Notices of 

Review. The decision to stop 

considering Category 2 species as 

candidates was designed to reduce 

confusion about the status of these 

species and to clarify that we no longer 

regarded these species as candidates for 

listing. 

Species Information 

The Spring Mountains acastus 

checkerspot butterfly (Chlosyne acastus 

robusta) is a subspecies of sagebrush 

checkerspot butterfly (Chlosyne acastus) 

belonging to the Nymphalidae (brushfooted butterflies) family. Synonyms of 

the genera Chlosyne have included 

Charidryas and Thessalia (Opler and 

Warren 2003, pp. 35–36). Early 

taxonomic assessments of specimens C. 

a. robusta ascribed it to C. a. 

vallismortis (= C. palla vallismortis; 

Austin 1981, p. 71). Later 

interpretations suggested that it was 

more closely aligned to C. acastus 

(Austin 1985, p. 108). Further 

evaluations resulted in recognition of 


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the Spring Mountains acastus 

checkerspot butterfly as a distinct 

subspecies (Austin 1998a, p. 576). There 

are nine subspecies of sagebrush 

checkerspot butterflies described for 

North America (Pelham 2008, pp. 379– 

380), of which four (C. a. acastus, C. a. 

dorothyi, C. a. robusta, and C. a. 

neumoegeni) occur in Nevada (Austin 

1998b, p. 842). 

The Spring Mountains acastus 

checkerspot butterfly is known only 

from the Spring Mountains in Clark and 

Nye Counties, Nevada (Austin 1998a, p. 

577), at elevations ranging from 

minimums near 1,800 meters (m) to 

maximums at 2,700 m (5,900–8,900 feet 

(ft); Weiss et al. 1997, p. 17). In low 

elevation desert areas adjacent to the 

distribution of Spring Mountains 

acastus checkerspot butterfly, a similar 

looking subspecies, C. a. neumoegeni, 

may occur (Austin 1998a, p. 577), and 

is likely the nearest subspecies spatially. 

The majority of observations and habitat 

for the Spring Mountains acastus 

checkerspot butterfly occur within the 

Spring Mountains National Recreation 

Area, which is managed by the U.S. 

Department of Agriculture, Forest 

Service (hereafter referred to as Forest 

Service), Humboldt-Toiyabe National 

Forest. However, one colony occurs on 

private property bordered by Forest 

Service managed lands, and an 

incidental observation at another 

location has been documented on lands 

managed by the U.S. Department of the 

Interior, Bureau of Land Management. 

Sagebrush checkerspot butterfly 

habitat is described as dry washes in 

sagebrush-juniper woodland, oak or 

mixed conifer woodland, and 

streambeds (Opler 1999, p. 199). 

Elevations used by Spring Mountains 

acastus checkerspot butterfly coincide 

with the intergraded upper elevation of 

Pinus monophylla–Juniperus 

osteosperma (pin ̃ yon-juniper) 

communities at 1,250–2,500 m (4,100– 

8,200 ft) and the lower elevation Abies 

concolor–Pinus ponderosa var. 

scopulorum (white fir-ponderosa pine) 

communities at 2,000–2,530 m (6,560– 

8,300 ft) (Niles and Leary 2007, 

pp. 5–6). Open vegetation communities 

associated with previous fire 

disturbances appear to be the preferred 

habitat (Boyd and Austin 2002, p. 5). 

Washes and linear features are used 

primarily as mating sites during the 

flight season (Boyd and Austin 2001, p. 

6; Boyd and Austin 2002, p. 5). 

Spring Mountains acastus checkerspot 

butterfly males may seek females all day 

by perching and sometimes patrolling 

gulches (Scott 1986, p. 307; Kingsley 

2008, pp. 7–8). Males may perch on 

several projecting objects in the same 

area such as rocks or branches (Scott 

1986, pp. 46–47, 307; Kingsley 2008, pp. 

4, 7–8). At these sites males behave 

territorially by remaining in the same 

area and pursuing any other butterflies 

or insects that come within a zone of a 

few square meters around the male and 

continue this behavior towards the 

intruding animal until it leaves (Boyd 

and Austin 2001, p. 5; Boyd and Austin 

2002, p. 5; Kingsley 2008, pp. 4, 7–8). 

During a brief flight season (Weiss et al. 

1997, pp. 6, 37), females remain at the 

site long enough to find a male to mate 

with, and then leave the area to oviposit 

(Boyd and Austin 2001, p. 6; Boyd and 

Austin 2002, p. 5). 

The flight season of the Spring 

Mountains acastus checkerspot is 

between mid-May and mid-July (Weiss 

et al. 1997, pp. 6, 37; Austin 1998a, p. 

576; Boyd 2004, pp. 1–2), peaking near 

the later part of June (Weiss et al. 1997, 

pp. 6, 37; Boyd and Austin 1999, p. 20; 

Boyd and Austin 2002, p. 4; Boyd 2004, 

p. 8). Distances moved during flight 

periods have not been documented, 

although Schrier et al. (1976, p. 285) 

observed that a related species, the 

northern checkerspot butterfly (C. 

palla), could move as far as 1.6 

kilometers (1 mile). During the flight 

season, Spring Mountains acastus 

checkerspot adults have been observed 

nectaring on Eriodictyon angustifolium 

(yerba santa), Heliomeris multiflora var. 

nevadensis (= Viguiera multiflora; 

Nevada golden-eye), Packera 

multilobata (= Senecio multilobatus; 

lobeleaf groundsel), unknown 

Ceanothus sp. (ceanothus species), 

unknown Melilotus sp. (clover species), 

Penstemon palmeri (Palmer penstemon), 

and an unknown Apocynum sp. 

(dogbane species) (Weiss et al. 1995, p. 

9; Boyd et al. 2000a, p. 6; Jones & Stokes 

2007a, p. 4). 

Chrysothamnus viscidiflorus has been 

documented as a larval host plant (Boyd 

and Austin 2002, p. 2; Austin and Leary 

2008, p. 99), and according to the 

petition, is common and widely 

distributed in the range (Boyd 2009, p. 

1). Common names used 

interchangeably among subspecies of C. 

viscidiflorus have included Douglas 

rabbitbrush, chamisa, green rabbitbrush, 

yellow rabbitbrush, viscid rabbitbrush, 

sticky leaved rabbitbrush, downy 

rabbitbrush, and narrow leaved 

rabbitbrush (Stubbendieck et al. 2003, p. 

249; Niles and Leary 2007, p. 19). Three 

subspecies of C. viscidiflorus have been 

documented in the Spring Mountains, 

including C. v. lanceolatus (variously 

known as viscid rabbitbrush, sticky 

leaved rabbitbrush, and yellow 

rabbitbrush), C. v. puberulus (downy 

rabbitbrush), and C. v. viscidiflorus 

(variously known as viscid rabbitbrush, 

sticky leaved rabbitbrush, and narrow 

leaved rabbitbrush) (Niles and Leary 

2007, p. 19). It is unknown which of 

these subspecies of C. viscidiflorus are 

used as a larval host by Spring 

Mountains acastus checkerspot 

butterfly. Of butterfly host plants 

described by Weiss et al. (1997, Figure 

4), Chrysothamnus viscidiflorus tends to 

be found in areas with the lowest 

percentages of tree canopy cover (mean 

of 17 percent) compared to other host 

plant species. 

Ericameria nauseosa 

(= Chrysothamnus nauseosus, rubber 

rabbitbrush) also is suspected of being a 

larval host plant (Weiss et al. 1997, p. 

6). Boyd and Austin (1999, pp. 20–21) 

attempted to feed E. nauseosa to Spring 

Mountains acastus checkerspot larvae 

unsuccessfully and reported that their 

results were inconclusive. However, 

they reported that other subspecies of 

sagebrush checkerspot butterflies used 

Acamptopappus sp. (goldenhead) and 

Xylorhiza sp. (woodyaster) as larval host 

plants (Austin and Austin 1980, as cited 

in Boyd and Austin 1999, p. 21). 

Clusters of eggs are laid on the 

underside of host leaves and sometimes 

on flower buds (Scott 1986, p. 307). 

After the eggs hatch, the young larvae 

cluster together on leaves or flowers 

(Scott 1986, p. 307). Similar to other 

members of the subfamily Nymphalinae 

and closely related subspecies, Spring 

Mountains acastus checkerspot larvae 

likely hibernate during the winter and 

may diapause [a period of arrested 

growth or reduced physiological 

activity, commonly induced by a 

seasonal change in photoperiod (i.e., 

day-length)] for many months or years 

(Scott 1986, pp. 27, 307). 

Weiss et al. (1997, p. 2) indicated that 

butterfly populations are highly 

dynamic, and from year to year, 

butterfly distributions can be highly 

variable. Butterflies may be restricted to 

moist and cool habitats during dry, 

warm periods, potentially expanding 

their distribution during periods marked 

by cooler and moister conditions (Weiss 

et al. 1997, pp. 2–3). Some species, such 

as the Spring Mountains acastus 

checkerspot butterfly, may exist as a 

metapopulation within the Spring 

Mountains (Weiss et al. 1997, p. 3). If 

this is the case, maintenance of 

dispersal corridors and unoccupied 

habitats is an important management 

consideration (Weiss et al. 1997, p. 3). 

The Spring Mountains acastus 

checkerspot butterfly occurs throughout 

the Spring Mountains and has been 

observed in 17 areas (Table 1). However, 

the number of occupied areas reported 

in past studies varies (12 occupied areas 


srobinson on DSKHWCL6B1PROD with PROPOSALS
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were reported in Boyd and Austin 1999, 

p. 20) based on how observations are 

spatially grouped. Four of these areas 

(Trough Spring, Kyle Canyon, Griffith 

Peak Trail/Harris Spring Road/Harris 

Mountain Road, and Potosi Mountain/ 

Mt. Potosi/Boy Scout Camp) are referred 

to interchangeably as colonies or 

population sites (Boyd & Austin 1999, 

pp. 9, 20–21; Boyd and Austin 2002, pp. 

5, 13; Boyd 2004, pp. 2–3). Currently, 

only four colonies are known to exist. 

However, the increased existence of 

incidental sighting areas and the 

potential subsequent dispersal of 

individuals may indicate the presence 

of additional unknown colonies (Boyd 

and Austin 1999, pp. 60–61; Boyd et al. 

2000, p. 10) (Table 1). 

TABLE 1—AREAS WHERE SPRING MOUNTAINS ACASTUS CHECKERSPOT OBSERVATIONS HAVE BEEN DOCUMENTED

[Areas ordered to begin with the most northern and end with the most southern] 

Observation area First year 

observed 

Mt. Stirling ......................................................................................................................................................................................... 1983. 

Big Timber Spring ............................................................................................................................................................................. 1995 or before. 

Wheeler Pass Road .......................................................................................................................................................................... 1987. 

Trough Spring * ................................................................................................................................................................................. 2001. 

McFarland Spring/Whisky Spring/Camp Bonanza ........................................................................................................................... 2003. 

Willow Spring/Willow Creek .............................................................................................................................................................. 1979. 

Clark Canyon .................................................................................................................................................................................... 1994. 

Foxtail Canyon .................................................................................................................................................................................. 1998. 

Deer Creek & Picnic Area ................................................................................................................................................................ 1965. 

Deer Creek Road (Telephone Canyon side) .................................................................................................................................... 1981 or 87. 

Kyle Canyon—lower ......................................................................................................................................................................... 1996 or before. 

Kyle Canyon—middle * ..................................................................................................................................................................... 1950. 

Kyle Canyon—upper ......................................................................................................................................................................... 1987. 

Griffith Peak Trail/Harris Spring Road/Harris Mountain Road * ....................................................................................................... 1990. 

Coal Spring ....................................................................................................................................................................................... 1992. 

Switchback Spring ............................................................................................................................................................................ 2003. 

Potosi Mountain/Mt. Potosi/Boy Scout Camp * ................................................................................................................................ 1995. 

* Asterisk indicates a colony. Colonies are isolated populations (Scott 1986, p. 108) based on mate locating behavior (Boyd and Austin 2002, 

p. 5; Boyd 2009, p. 1) of one or more males observed over a period of time and represent more than one incidental observation or sighting. 

Sources: Weiss et al. 1995, pp. 4 and 19; Weiss et al. 1997, pp. 6–7, 47; Boyd and Austin 1999, pp. 19–21; Boyd 2004, pp. 2–3; Nevada Natural Heritage Program 2009. 

A colony is ‘‘a local, isolated 

population’’ (Scott 1986, p. 108). Past 

researchers defined colonies of Spring 

Mountains acastus checkerspot 

butterflies based on the mate locating 

behavior of males, also referred to as 

mate locating sites (Boyd and Austin 

2002, p. 5; Boyd 2009, p. 1). The 

remaining 13 areas are referred to as 

incidental observations or sighting areas 

(Boyd and Austin 2001, p. 2; Boyd and 

Austin 2002, p. 3; Boyd 2004, p. 3), 

where intermittent observations of a few 

butterflies were recorded at a location. 

The areas where the Spring Mountains 

acastus checkerspot butterfly has been 

observed in a colony or sighting area 

represent the overall known population 

of the subspecies. 

The largest known colony occurs at 

Griffith Peak Trail/Harris Spring Road/ 

Harris Mountain Road, and was first 

documented as a sighting area in 1990 

and later described as a potential colony 

in 1999 (Boyd and Austin 1999, p. 20). 

The Trough Spring colony was first 

identified in 2001 (Boyd and Austin 

2002, p. 5). Boyd (2004, p. 3) stated that 

a single male observed at Willow 

Spring/Willow Creek in 2003 may have 

dispersed from Trough Spring or 

another unknown colony, due to its not 

being sighted in the area since the 

1980s. The Spring Mountains acastus 

checkerspot butterfly was first 

documented at Potosi Mountain/Mt. 

Potosi/Boy Scout Camp in 1995 (Weiss 

et al. 1995, p. 6), and was described as 

a colony for the first time in 2000 (Boyd 

et al. 2000a, p. 4). 

DataSmiths (2007, p. 17) concluded 

that absence of adults at a site does not 

necessarily equate to ephemeral 

occupation or extirpation. Observations 

in areas reported for the Spring 

Mountains acastus checkerspot butterfly 

illustrate this. Boyd et al. (2000a, p. 4) 

searched 17 areas for the Spring 

Mountains acastus checkerspot butterfly 

in 1999; these 17 areas consisted of 8 

historical and 9 potential sites. Spring 

Mountains acastus checkerspot 

butterflies were observed at five of the 

eight historical sites visited and two of 

these were described as potential new 

colonies. In later reports of surveys 

occurring in 2003, the Spring Mountains 

acastus checkerspot butterfly was 

observed again in the Willow Spring/ 

Willow Creek area (Boyd 2004, pp. 2– 

3), where it was not observed during 

surveys in 1999 (Boyd and Austin 1999, 

p. 98–Table 7). Similarly, in 2003, the 

Spring Mountains acastus checkerspot 

butterfly also was observed in the 

McFarland Spring/Whisky Spring/Camp 

Bonanza area for the first time (Boyd 

2004, p. 2), even though it was not 

observed there during previous surveys 

in 1998 (Boyd and Austin 1999, p. 104– 

Table 12). These examples demonstrate 

that not seeing individuals at a site 

during surveys does not necessarily 

equate with extirpation because adult 

surveys will not detect diapausing (in a 

physiological state of dormancy) larvae, 

and short adult flight periods coupled 

with low numbers may drastically 

reduce the likelihood of observing 

Spring Mountains acastus checkerspot 

butterflies. 

Yearly population variation of the 

Spring Mountains acastus checkerspot 

butterfly also is expressed by variation 

in the numbers of observed individuals 

during repeat surveys at the same 

location (Table 2). At the Griffith Peak 

Trail/Harris Spring Road/Harris 

Mountain Road site, surveys from 2000 

and 2001 revealed that the highest total 

number of individuals observed on a 

single day increased from 19 to 104. In 

2003, the highest number observed on a 

single day at the same site decreased to 

27. In a 2006 interview with the 

petitioner, Boyd reported that the 

Spring Mountains acastus checkerspot 

butterfly had ‘‘done better’’ than other 

endemic species and had ‘‘good 

numbers’’ at Griffith Peak Trail/Harris 

Spring Road/Harris Mountain Road 

(Boyd 2006, pers. comm.), as well as at 


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Potosi Mountain/Mt. Potosi/Boy Scout 

Camp (Boyd 2006, p. 2). At locations 

where it was observed in 2006, the 

petition states that the butterfly 

appeared to be in ‘‘appropriate’’ numbers 

(Boyd 2006, p. 2). These observations 

support the conclusions of Weiss et al. 

(1997, p. 2) of highly dynamic butterfly 

populations where observations may 

occur periodically throughout a species’ 

range, and populations at colony sites 

may fluctuate as indicated by 

monitoring counts. 

TABLE 2—SUMMARY OF MONITORING RESULTS OF SPRING MOUNTAINS ACASTUS CHECKERSPOT BUTTERFLY AT THREE

COLONY SITES

Year 1999 2000 2001 2002 2003 2006 2007 2008 

Kyle Canyon (middle): 

Highest #/day .......................................... 5 ............. 6 ............. 8 ............. 6 ............. 7 ............. 4 ............. 1 ............. 4. 

Highest # male/day ................................. 4 ............. 6 ............. 8 ............. 6 ............. 7 ............. 4 ............. 1 ............. 4. 

Highest # female/day .............................. 1 ............. 1 ............. 1 ............. 0 ............. 1 ............. 0 ............. 0 ............. 0. 

# Visits ..................................................... 11 ........... 9 ............. 6 ............. 4 ............. 4 ............. 1 ............. 6 ............. 8. 

Peak date(s) ............................................ June 19 .. June 15 

& 30.

June 18 .. June 24 .. June 10 .. June 21 .. June 13 

& 21.

June 24. 

Griffith Peak Trail/Harris Spring Road/Harris 

Mountain Road: 

Highest #/day .......................................... ................ 19 ........... 104 ......... 50 ........... 27.

Highest # male/day ................................. ................ 12 ........... 78 ........... 43 ........... 17.

Highest # female/day .............................. ................ 5 ............. 26 ........... 9 ............. 10.

# Visits ..................................................... ................ 9 ............. 5 ............. 5 ............. 4.

Peak date ................................................ ................ June 11 .. June 18 .. June 20 .. June 29.

Trough Spring: 

Highest #/day .......................................... ................ ................ ................ 20 ........... 41.

Highest # male/day ................................. ................ ................ ................ 18 ........... 40.

Highest # female/day .............................. ................ ................ ................ 7 ............. 3.

# Visits ..................................................... ................ ................ ................ 3 ............. 5.

Peak date ................................................ ................ ................ ................ June 18 .. June 1.

Sources: (Boyd 2004, p. 8; Jones and Stokes 2007a, p. 4; Jones and Stokes 2007b, p. 3; Kingsley 2008, p. 3). 

Evaluation of Information for This 

Finding 

Section 4 of the Act (16 U.S.C. 1533) 

and its implementing regulations at 50 

CFR 424 set forth the procedures for 

adding a species to, or removing a 

species from, the Federal Lists of 

Endangered and Threatened Wildlife 

and Plants. A species may be 

determined to be an endangered or 

threatened species due to one or more 

of the five factors described in section 

4(a)(1) of the Act: 

(A) The present or threatened 

destruction, modification, or 

curtailment of its habitat or range; 

(B) Overutilization for commercial, 

recreational, scientific, or educational 

purposes; 

(C) Disease or predation; 

(D) The inadequacy of existing 

regulatory mechanisms; or 

(E) Other natural or manmade factors 

affecting its continued existence. 

In considering what factors might 

constitute threats, we must look beyond 

the exposure of the species to a 

particular factor to evaluate whether the 

species may respond to that factor in a 

way that causes actual impacts to the 

species. If there is exposure to a factor 

and the species responds negatively, the 

factor may be a threat and we attempt 

to determine how significant a threat it 

is. The threat may be significant if it 

drives, or contributes to, the risk of 

extinction of the species such that the 

species may warrant listing as 

endangered or threatened as those terms 

are defined by the Act. The 

identification of factors that could 

impact a species negatively may not be 

sufficient to compel a finding that 

substantial information has been 

presented suggesting that listing may be 

warranted. The information should 

contain evidence or the reasonable 

extrapolation that any factor(s) may be 

an operative threat that acts on the 

species to the point that the species may 

meet the definition of endangered or 

threatened under the Act. 

In making this 90-day finding, we 

evaluated whether information 

regarding the threats to the Spring 

Mountains acastus checkerspot 

butterfly, as presented in the petition 

and other information available in our 

files, is substantial, thereby indicating 

that the petitioned action may be 

warranted. Our evaluation of this 

information is presented below. 

For Factors A and E, we provide a 

discussion of our evaluation for each of 

the four known colonies. In addition, for 

Factor A, we discuss threats as they 

relate to all colonies. For Factors B, C, 

and D, we provide a discussion of our 

evaluation for the entire subspecies. 

A. The Present or Threatened 

Destruction, Modification, or 

Curtailment of Its Habitat or Range 

Information Provided in the Petition 

Concerning All Sites 

The petition states that the overall 

numbers of all ‘‘covered’’ butterfly 

species in the Spring Mountains are 

declining, as seen with Plebejus 

(= Icaricia) shasta charlestonensis 

(Mt. Charleston blue butterfly). 

Specifically, the petition states that 

declines became apparent by 2005 and 

were exacerbated during the 2006, 2007, 

and 2008 seasons (Boyd 2009, p. 2). No 

data were reported for the 2009 season. 

In addition, the petition noted several 

conservation agreements or plans exist 

to conserve the subspecies; however, 

few of the obligations documented in 

these agreements and plans have been 

met. The petitioner also states that 

monitoring requirements outlined in 

these agreements or plans were 

abandoned after 2003 (Boyd 2009, pp. 

1–2). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning All Sites 

Between 1998 and 2002, butterfly 

monitoring occurred throughout the 

Spring Mountains (Boyd and Austin 

1999, pp. 1–77; Boyd et al. 2000a, pp. 

1–24; Boyd et al. 2000b, pp. 1–8; Boyd 

and Austin 2001, pp. 1–15; Boyd and 


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Austin 2002, pp. 1–15; Dewberry et al. 

2002, pp. 1–16; Boyd 2004, pp. 1–10). 

Butterfly numbers fluctuated between 

and within sites during this time (see 

Table 2 above). Many unknown 

elements exist pertaining to the 

petitioner’s site visits including: (1) 

Survey protocol standards, (2) number 

of visits, (3) timing of visits, and (4) 

weather conditions during the visits. 

Since 2003, inventory efforts primarily 

have occurred where proposed activities 

may affect the subspecies (DataSmiths 

2007, pp. 1–31; Forest Service 2007a, 

pp. 1–9; Forest Service 2007b, pp. 1–57; 

Jones and Stokes 2007a pp. 1–73; Jones 

and Stokes pp. 2007b 1–50; Kingsley 

2008, pp. 1–18). Such project-specific 

monitoring assists in determining 

potential project impacts. Monitoring 

for populations and habitats of Spring 

Mountains acastus checkerspot butterfly 

has occurred purposefully, but 

intermittently, with different levels of 

effort, at various locations throughout 

its range. These differences and 

inconsistencies in monitoring make it 

difficult to determine the cause-andeffect relationships associated with 

activities that may affect the Spring 

Mountains acastus checkerspot butterfly 

(see Factor E discussion below for 

information on butterfly population 

trends in general). 

The Spring Mountains acastus 

checkerspot butterfly is included in a 

1998 Conservation Agreement for the 

Spring Mountains National Recreation 

Area (Conservation Agreement) to 

facilitate cooperation among the parties 

(U.S. Forest Service, U.S. Fish and 

Wildlife Service, and State of Nevada 

Department of Conservation and Natural 

Resources) in providing long-term 

protection for the rare and sensitive 

flora and fauna of the Spring Mountains 

(Forest Service 1998). The Conservation 

Agreement describes voluntary 

conservation actions (described below) 

for the butterfly on lands within the 

Forest Service’s jurisdiction (Forest 

Service 1998, pp. 44–49); these 

voluntary conservation actions were 

intended to protect the subspecies and 

its habitat. Those actions include 

research, inventory, and monitoring. 

The petition states that very few of the 

conservation actions in the 

Conservation Agreement have been 

completed and that monitoring of sites 

was abandoned in 2003 (Boyd 2009, p. 

2). The conservation actions outlined in 

the Conservation Agreement were to be 

carried out within a 5-year period 

between 1998 and 2002 (Forest Service 

1998, p. 28). Between 1998 and 2002, 

butterfly monitoring occurred 

throughout the Spring Mountains (Boyd 

and Austin 1999; Boyd et al. 2000a; 

Boyd et al. 2000b; Boyd and Austin 

2001; Boyd and Austin 2002; Dewberry 

et al. 2002; Boyd 2004). The frequency, 

intensity, and extent of monitoring have 

varied since 2003. 

The Spring Mountains acastus 

checkerspot butterfly is a covered 

species under the Clark County Multiple 

Species Habitat Conservation Plan 

(MSHCP). The Clark County MSHCP 

identifies two goals for the Spring 

Mountains acastus checkerspot: (a) 

‘‘Maintain stable or increasing 

population numbers and host and larval 

plant species’’; and (b) ‘‘No net 

unmitigated loss of larval host plant or 

nectar plant species habitat’’ (RECON 

2000a, Table 2.5, pp. 2–154; RECON 

2000b, pp. B162–B164). The Forest 

Service is one of several signatories on 

the Implementing Agreement for the 

Clark County MSHCP because many of 

the activities from the 1998 

Conservation Agreement were 

incorporated into the MSHCP. 

Primarily, activities undertaken by the 

Forest Service focused on conducting 

surveys and monitoring for butterflies. 

Although the Forest Service, Clark 

County, and the Service contracted 

some surveys and monitoring (see 

above), a butterfly monitoring plan was 

not fully implemented. The lack of 

inventory or monitoring does not 

directly correlate to any threat to the 

Spring Mountains acastus checkerspot 

butterfly or its habitat. However, 

monitoring population status may assist 

with identifying potential responses to 

threats. 

In 2004, the Forest Service and the 

Service entered into a voluntary 

memorandum of agreement (MOA) to 

establish an interagency commitment to 

early communication, coordination, and 

conferencing to guide project 

development on Forest Service lands 

that provide habitat for the Spring 

Mountains acastus checkerspot butterfly 

(Forest Service and Service 2004, p. 1). 

This MOA is intended to ensure that 

forest activities are designed to reduce 

impacts to listed species under 

conservation agreements or habitat 

conservation plans (Forest Service and 

Service 2004, p. 4). 

In 2007, a survey protocol was 

prepared to survey or inventory 

butterflies of concern at sites subject to 

Forest Service management (Forest 

Service et al. 2007, p. 1). The butterfly 

inventory techniques, of assessing 

habitat and walking survey transects, 

were utilized to maximize the 

possibility of encountering targeted 

adult butterflies (Forest Service et al. 

2007, p. 1). Monitoring of the Spring 

Mountains acastus checkerspot butterfly 

has occurred where activities may 

potentially affect the subspecies and its 

habitat (e.g., DataSmiths 2007; Forest 

Service 2007a; Forest Service 

2007b;Jones and Stokes 2007a; Jones 

and Stokes 2007b; Kingsley 2008), but it 

is unclear which conservation actions 

have taken place since 2003. 

Information Provided in the Petition 

Concerning the Kyle Canyon (Middle) 

Colony Site 

The petition notes that when this site 

has been surveyed, adults of both sexes 

of the Spring Mountains acastus 

checkerspot butterfly are consistently 

present, but that the numbers of 

individuals found are low (Boyd 2009, 

p. 3). The petitioners assert that threats 

at the Kyle Canyon (middle) colony 

include highway modifications 

(expansions, grading, and wash 

realignments), power line maintenance, 

fuels reduction or treatment projects, 

and equestrian and vehicle traffic (Boyd 

2009, p. 3). The petition also notes 

(Boyd 2009, p. 3) plans for a large Forest 

Service visitor’s complex at the site of 

a former golf course, and construction of 

a hiking trail. The proposed hiking trail 

was asserted to traverse the length of the 

breeding site (Boyd 2009, p. 3). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Kyle Canyon 

(Middle) Colony Site 

Information in Service files suggests 

that this colony site is small relative to 

the other colonies, but likely stable (see 

Table 1 above). Individuals have been 

found every season the site is surveyed, 

and the numbers of individuals found 

during surveys are consistently low. The 

petition states that this population has 

been declining since the late 1990s, but 

the data we have available indicate that 

the numbers at this site are low every 

year (see Table 2 above). 

We have no additional recent 

information in our files concerning 

threats from highway modifications 

(expansions, grading, and wash 

realignments), power line maintenance, 

and equestrian and vehicle traffic. Our 

files contain a 1999 report (Boyd and 

Austin 1999, p. 59) that lists a number 

of habitat-related factors that could 

adversely affect the Spring Mountains 

acastus checkerspot butterfly in the Kyle 

Canyon area including grading, sod 

dumping, large vehicle occurrence as 

indicated by tracks, and clearing. 

Neither the 1999 report nor the petition 

provides any information or supporting 

references that characterize the scope, 

immediacy, and intensity of any of these 

potential stressors. 


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Our files contain information on both 

the beneficial and negative impacts of 

recent fuels reduction projects. Fuels 

reduction projects are designed to 

reduce the volume and cover of woody 

vegetation. Some potential negative 

impacts of fuels reduction projects 

include the crushing of larvae, 

reductions in larval host plants or adult 

nectar plants, and reductions in the 

number of male perching or mate 

location sites. The most recent fuels 

reduction project is the Spring 

Mountains National Recreation Area 

Hazardous Fuels Reduction Project 

(Forest Service 2007a, pp. 1–9; Forest 

Service 2007b, pp. 1–57). Design criteria 

outlined in the environmental 

assessment for this project (Forest 

Service 2007b, Appendix B Design 

Criteria W5, W6, W7, and M1) were 

developed to address impacts to the 

Spring Mountains acastus checkerspot 

and other butterflies included in the 

Conservation Agreement, and provided 

for surveys of butterflies and habitat, 

habitat mapping, abstaining from any 

host plant removal in core colonies, 

avoidance of host plants, minimization 

of disturbance by using manual 

methods, monitoring during 

implementation, and post-project 

monitoring of butterflies and their 

habitat. The Forest Service began 

implementation of the Spring 

Mountains Hazardous Fuels Reduction 

Project in 2008, including employment 

of associated design criteria and 

conservation measures. A monitoring 

program is underway to assess the 

impacts and benefits to butterfly host 

plants. 

The information indicates that fuels 

treatment projects can have short-term, 

negative impacts to habitat and 

individuals, or loss of viability (Forest 

Service 2007a, pp. 18, 22–23). Even 

though the impact duration is shortterm, given the small documented 

population at the Kyle Canyon (middle) 

site, any short-term, negative impact 

could be a threat to this colony (see 

Table 2 above). 

Fuels treatment projects may be 

beneficial to habitat and individuals by 

reducing the risk of wildfire in the 

localized areas where the Spring 

Mountains acastus checkerspot butterfly 

occurs. Over the long term, fuels 

reductions may improve habitat by 

increasing nectar and host plant 

availability. Studies of treatments in 

other areas of pin ̃ yon-juniper showed 

correlated increases of nectar plants, 

host plants, and butterflies (Koniak 

1985, p. 559; Kleintjes et al. 2004, pp. 

235–236). The one known larval host, 

green rabbitbrush, re-sprouts or invades 

vigorously after fires or other 

disturbances (Koniak 1985, p. 559). The 

Spring Mountains acastus checkerspot 

butterfly could benefit from fuels 

treatment activities after a period of 

time as the treatments improve nectar or 

host plant availability. 

Information in our files confirms 

plans for a visitor center and associated 

trail, but does not indicate that these 

projects will have a significant negative 

impact on the Spring Mountains acastus 

checkerspot butterfly. Design criteria 

and measures were incorporated into 

the project, specifically into the design 

of a hiking trail in or along Kyle Canyon 

Wash, to prevent and minimize impacts 

to the Spring Mountains acastus 

checkerspot butterfly (Forest Service 

2009, pp. 4–5). These criteria and 

measures include employing 

construction techniques to avoid or 

minimize temporary disturbance 

through known Spring Mountains 

acastus checkerspot butterfly breeding 

areas, prohibit construction of Kyle 

Canyon Wash Trail and buried utilities 

from early May to mid-July (to avoid the 

butterfly’s flight season), erect 

temporary construction fencing along 

the proposed construction limits of 

planned improvements prior to any 

ground-disturbing activities, require the 

contractor to contain all construction 

activities within the approved 

construction limits, maintain temporary 

fencing until notified by the Contracting 

Officer, collect native seed from 

appropriate larval host and nectar plants 

and revegetate temporary construction 

disturbance areas following completion 

of construction, implement construction 

dust control measures to minimize 

impacts to blooming nectar plant 

populations, reduce off-trail use in 

documented Spring Mountains acastus 

checkerspot breeding/mate selection 

areas, and construct a fence/barrier 

adjacent to the newly constructed trail 

in Kyle Canyon Wash. When the project 

is implemented in 2011, or later, the 

incorporated design criteria and 

measures should avoid or limit impacts 

to the Spring Mountains acastus 

checkerspot butterfly in Kyle Canyon 

Wash. Any impacts to the Spring 

Mountains acastus checkerspot butterfly 

in Kyle Canyon Wash are anticipated to 

be minor, and negligible to the overall 

population of the subspecies at this site. 

Information Provided in the Petition 

Concerning the Potosi Mountain/Mt. 

Potosi/Boy Scout Camp Colony Site 

The petition asserts that a 2007 fuels 

reduction project stacked cut waste 

more than a meter high along and on 

both sides of the dirt road at this site, 

effectively blocking all male perching/ 

mate locating sites (Boyd 2009, p. 3). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Potosi Mountain/ 

Mt. Potosi/Boy Scout Camp Colony Site 

We have no information in our files 

to dispute or support the assertion that 

blocking has occurred or could threaten 

the Spring Mountains acastus 

checkerspot butterfly at this colony site. 

We interpret the term ‘‘blocked’’ to mean 

obstruction of male perching/mate 

locating sites as a result of these areas 

being covered by debris. There is no 

information in our files to determine if, 

or to what extent, the alleged blocking 

of male perching sites is still occurring 

at this site. Though the numbers of sites 

available for perching by males may be 

reduced temporarily if cut waste is piled 

for later treatment (commonly chipping 

or burning), other sites may be available, 

as the Spring Mountains acastus 

checkerspot butterfly has been observed 

using multiple perch sites during mate 

locating (Kingsley 2008, pp. 4, 7–8). 

As noted above, fuels reduction 

projects may have a short-term, negative 

impact by reducing the number of male 

perching/mate locating sites. The 

petition provided no population 

estimates for this colony, nor do we 

have any information in our files 

regarding population estimates for this 

colony. However, the petition states that 

individuals of both sexes were found at 

the site in 2006, but no individuals were 

found during the 2007 flight season 

(Boyd 2009, p. 3). No surveys have been 

completed since 2007. 

Information Provided in the Petition 

Concerning the Griffith Peak Trail/ 

Harris Spring Road/Harris Mountain 

Road Colony Site 

The petition states that there is no 

immediate threat to habitat or range, as 

a whole, at this site (Boyd 2009, pp. 

3–4). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Griffith Peak Trail/ 

Harris Spring Road/Harris Mountain 

Road Colony Site 

We have no additional information on 

threats to the Spring Mountains acastus 

checkerspot butterfly’s habitat or range 

at this site. 

Information Provided in the Petition 

Concerning the Trough Spring Colony 

Site 

The petition asserts that horses and 

introduced elk are having negative 

effects on the Trough Spring colony site 

(Boyd 2009, p. 4). The petition also 

indicates that while the site is closed to 

off-highway vehicle use, violations are 

not uncommon (Boyd 2009, p. 4). In 


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20620 Federal Register / Vol. 76, No. 71 / Wednesday, April 13, 2011 / Proposed Rules 

addition, the petition states that 20 

individuals were found when the site 

was surveyed in 2002, 41 individuals 

were found during surveys in 2003, but 

0 individuals were found during a 2007 

visit to the site (Boyd 2009, p. 4). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Trough Spring 

Colony Site 

We have no information in our files 

to dispute or support the assertion that 

the area is used by horses, elk, and offhighway vehicles. However, neither the 

petition nor any available information 

in our files provides any information or 

supporting references that describe the 

scope, immediacy, and intensity of any 

of these potential stressors. 

During three site visits in 2002, the 

highest total number of individuals 

counted was 20. During five site visits 

in 2003, the highest total number of 

individuals counted was 41 (see Table 

2 above). While the petition notes a 

single site visit in 2007 where no 

individuals were found, conducting a 

single visit during the flight period is 

not in accordance with standard 

butterfly monitoring protocol, and is not 

considered adequate to gauge 

abundance or derive trends. However, 

because we have no recent survey data 

for this site, we cannot rule out the 

possibility that the 2007 survey result of 

zero individuals may indicate a 

downward trend in numbers at this site. 

Summary of Factor A 

Fuels reduction projects, horses and 

introduced elk, and off-highway 

vehicles may negatively affect Spring 

Mountains acastus checkerspot butterfly 

individuals and habitat. All of these 

activities could negatively alter habitat 

through one or more of the following 

mechanisms: Crushing larvae, reducing 

the amounts of larval host plants, 

reducing the amount of adult nectar 

plants, and reducing the amount of male 

perching/mate location sites. Declines 

in numbers of individuals have been 

observed at sites where fuels reduction 

projects (Potosi Mountain/Mt. Potosi/ 

Boy Scout Camp Colony Site), horses 

and introduced elk (Trough Spring 

Colony Site), and off-highway vehicle 

activities (Trough Spring Colony Site) 

occur. This provides evidence to suggest 

that the Spring Mountains acastus 

checkerspot butterfly may be negatively 

affected by these activities. In summary, 

we find that the information provided in 

the petition, as well as other 

information in our files, presents 

substantial information indicating that 

the petitioned action may be warranted 

due to the present or threatened 

destruction, modification, or 

curtailment of the species’ habitat or 

range, specifically because of fuels 

reduction projects, horses and 

introduced elk, and off-highway 

vehicles. 

B. Overutilization for Commercial, 

Recreational, Scientific, or Educational 

Purposes 

Information Provided in the Petition 

There was no information provided in 

the petition regarding the 

overutilization for commercial, 

recreational, scientific, or educational 

purposes being a threat to the Spring 

Mountains acastus checkerspot 

butterfly. 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files 

Neither the petition nor information 

in our files provides any information 

pertaining to threats under this factor 

with regard to the Spring Mountains 

acastus checkerspot butterfly. Therefore, 

we find that the information provided in 

the petition, as well as other 

information in our files, does not 

indicate or document that 

overutilization for commercial, 

recreational, scientific, or educational 

purposes poses a threat to the species. 

However, we will evaluate all factors, 

including overutilization from 

commercial, recreational, scientific, or 

educational purposes, when we conduct 

the status review. 

C. Disease or Predation 

Information Provided in the Petition 

There was no information provided in 

the petition regarding disease or 

predation being a threat to the Spring 

Mountains acastus checkerspot 

butterfly. 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files 

Neither the petition nor information 

in our files provides any information 

pertaining to disease or predation with 

regard to the Spring Mountains acastus 

checkerspot butterfly. Therefore, we 

find that the information provided in 

the petition, as well as other 

information in our files, does not 

indicate or document that disease or 

predation poses a threat to the species. 

However, we will evaluate all factors, 

including disease and predation, when 

we conduct the status review. 

D. The Inadequacy of Existing 

Regulatory Mechanisms 

Information Provided in the Petition 

There was no information provided in 

the petition regarding the inadequacy of 

existing regulatory mechanisms being a 

threat to the Spring Mountains acastus 

checkerspot butterfly. 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files 

The petition does not provide any 

information pertaining to the 

inadequacy of existing regulatory 

mechanisms with regard to the Spring 

Mountains acastus checkerspot 

butterfly. In addition, the Service files 

do not provide any information 

pertaining to the inadequacy of existing 

regulatory mechanisms for the Spring 

Mountains acastus checkerspot 

butterfly. Therefore, we find that the 

information provided in the petition, as 

well as other information in our files, 

does not indicate or document that the 

inadequacy of existing regulatory 

mechanisms poses a threat to the 

species. However, we will evaluate all 

factors, including the inadequacy of 

existing regulatory mechanisms, when 

we conduct the status review. 

E. Other Natural or Manmade Factors 

Affecting the Subspecies’ Continued 

Existence 

Information Provided in the Petition 

Concerning the Kyle Canyon (Middle) 

Colony Site 

The petition (Boyd 2009, p. 3) asserts 

highway contaminants, road salt, 

equestrian and vehicle traffic, and 

increasing abundance of Medicago sp., a 

nonnative alfalfa species, are threats to 

Spring Mountains acastus checkerspot 

butterfly at the Kyle Canyon (middle) 

colony site. 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Kyle Canyon 

(Middle) Colony Site 

We have no information or supporting 

references that characterize the scope, 

immediacy, and intensity of any of these 

potential stressors. However, the small 

documented population at this site may 

increase the vulnerability of the Spring 

Mountains acastus checkerspot butterfly 

to other potential threats. We will 

further investigate these potential 

threats as they pertain to the Spring 

Mountains acastus checkerspot butterfly 

during our status review for this 

subspecies. 


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Federal Register / Vol. 76, No. 71 / Wednesday, April 13, 2011 / Proposed Rules 20621 

Information Provided in the Petition 

Concerning the Potosi Mountain/Mt. 

Potosi/Boy Scout Camp Colony Site 

The petition asserts that a protracted 

drought is adding to the stresses 

associated with the fuels reduction 

project at the Potosi Mountain/Mt. 

Potosi/Boy Scout Camp site (Boyd 2009, 

p. 3). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Potosi Mountain/ 

Mt. Potosi/Boy Scout Camp Colony Site 

It has been observed that during 

drought, butterfly populations may be 

lower (Ehrlich et al. 1980, pp. 101–105; 

Thomas 1984, p. 344). In 2006, 

populations of many butterfly species 

were low throughout southern Nevada, 

south of the Great Basin, likely as a 

result of drought conditions (Murphy 

2006, p. 3). In 2007, other species of 

butterflies in the Spring Mountains 

experienced population declines, and 

these declines were hypothesized to be 

a result of drought (Datasmiths 2007, p. 

22). While Boyd (2008, p. 2) speculated 

that populations of other butterfly 

species may have declined as a result of 

drought and other factors, population 

trends of the Spring Mountains acastus 

checkerspot butterfly were not being 

specifically monitored. Though 

populations may be low during some 

years as a result of drought, checkerspot 

species (Chlosyne sp.) may survive 

unfavorable weather years by 

diapausing for 2 or more years (Scott 

1986, p. 307). Drought may not be a 

threat, in and of itself, to the Spring 

Mountains acastus checkerspot 

butterfly. However, drought coupled 

with other factors, such as fuels 

reduction projects and other manmade 

stressors, may result in the Spring 

Mountains acastus checkerspot butterfly 

being more susceptible to other threats. 

Information Provided in the Petition 

Concerning the Griffith Peak Trail/ 

Harris Spring Road/Harris Mountain 

Road Colony Site 

The petition asserts that disturbance 

by vehicle and hiking traffic are threats 

at the Griffith Peak Trail/Harris Spring 

Road/Harris Mountain Road colony site 

as a result of direct disturbanceS to the 

butterflies by vehicles and hikers (Boyd 

2009, pp. 3–4). According to the 

petition, use of the road and trail 

appears to be increasing, which disturbs 

the butterflies during the flight period. 

The petition states that the numbers of 

individuals found during surveys at this 

site have continued to decline each year 

beginning with 104 individuals in 2001, 

50 individuals in 2002, 27 individuals 

in 2003, and 3 individuals in 2007 

(Boyd 2009, p. 4). This site has not been 

visited since 2007. 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Griffith Peak Trail/ 

Harris Spring Road/Harris Mountain 

Road Colony Site 

We have no information in our files 

to support or dispute the assertion that 

hikers and vehicular traffic are 

disturbing Spring Mountains acastus 

checkerspot butterflies at this site. 

Neither the petition nor any available 

information in our files provides any 

information or supporting references 

that characterize the scope, immediacy, 

and intensity of any of these potential 

stressors. Surveys found butterfly 

numbers fluctuated from 19 individuals 

in 2000, to 104 individuals in 2001, to 

50 individuals in 2002, to 27 

individuals in 2003 (see Table 2 above). 

However, differences and 

inconsistencies in monitoring make it 

difficult to interpret survey results. 

Based on the available information, 

there appears to be a potential 

population decline at the Griffith Peak 

Trail/Harris Spring Road/Harris 

Mountain Road colony site. The petition 

states that vehicle and hiking traffic that 

disturb the butterfly during the flight 

period may be a threat to the Spring 

Mountains acastus checkerspot 

butterfly. 

Information Provided in the Petition 

Concerning the Trough Spring Colony 

Site 

Even though this site is relatively 

remote and is closed to motorized 

vehicles, the petition asserts that traffic 

from off-highway vehicle activity does 

occur, and is a threat at the Trough 

Spring site (Boyd 2009, p. 4). The 

petition also states that 20 individuals 

were found when the site was surveyed 

in 2002, and 41 individuals were found 

during surveys in 2003, but 0 

individuals were found during a 2007 

site visit conducted during the 

appropriate time of year (Boyd 2009, 

p. 4). 

Evaluation of Information Provided in 

the Petition and Available in Service 

Files Concerning the Trough Spring 

Colony Site 

We have no information or supporting 

references that characterize the scope, 

immediacy, and intensity of this 

potential threat. However, based on the 

available information, there appears to 

be a potential recent population decline 

at the Trough Spring colony site. The 

petition states that illegal motorized 

vehicle activity may be a threat to the 

Spring Mountains acastus checkerspot 

butterfly at this site. 

Summary of Factor E 

Based on the available information, 

there appears to be potential population 

declines at the Griffith Peak Trail/Harris 

Spring Road/Harris Mountain Road 

colony site and the Trough Spring 

colony sites. The petition states that 

vehicle and hiking traffic that disturb 

the butterfly during the flight period 

may be a threat to the Spring Mountains 

acastus checkerspot butterfly, and we 

will further evaluate this in our status 

review. Information provided by the 

petition and available in our files 

suggests that drought may be a potential 

added stressor to the Spring Mountains 

acastus checkerspot butterfly at some 

locations where additional threats 

occur. In summary, we find that the 

information provided in the petition, as 

well as other information in our files, 

presents substantial information 

indicating that the petitioned action 

may be warranted due to other natural 

or manmade factors affecting the 

subspecies’ continued existence, 

specifically because of vehicle and 

hiking traffic and drought. 

Finding 

On the basis of our evaluation of the 

petition under section 4(b)(3)(A) of the 

Act, we determine that the petition 

presents substantial scientific or 

commercial information indicating that 

listing the Spring Mountains acastus 

checkerspot butterfly may be warranted. 

This finding is based on information 

provided under Factors A and E. We 

determine that the information provided 

under Factors B, C, and D is not 

substantial. The available information 

indicates fuels reduction projects may 

have a negative impact on Spring 

Mountains acastus checkerspot butterfly 

individuals and habitat. The possible 

declining trends at the Potosi Mountain/ 

Mt. Potosi/Boy Scout Camp Colony Site 

indicate that fuels reduction projects 

may be a threat to the Spring Mountains 

acastus checkerspot butterfly at this site 

(Factor A). In addition, potential 

declining population trends at the 

Griffith Peak Trail/Harris Spring Road/ 

Harris Mountain Road colony site and 

the Trough Spring colony site indicate 

that vehicle and hiking traffic that 

disturb the butterfly flight period may 

be a threat to the subspecies (Factor E). 

Additionally, drought (Factor E) may be 

an added stressor to the Spring 

Mountains acastus checkerspot butterfly 

at some locations where additional 

threats occur. 

Because we have found that the 

petition presents substantial 


srobinson on DSKHWCL6B1PROD with PROPOSALS
20622 Federal Register / Vol. 76, No. 71 / Wednesday, April 13, 2011 / Proposed Rules 

information indicating that listing may 

be warranted, we are initiating a status 

review to determine whether listing the 

Spring Mountains acastus checkerspot 

butterfly under the Act is warranted. All 

relevant information pertaining to each 

of the five factors will be fully evaluated 

in the forthcoming status review. 

The ‘‘substantial information’’ 

standard for a 90-day finding differs 

from the Act’s ‘‘best scientific and 

commercial data’’ standard that applies 

to a status review to determine whether 

a petitioned action is warranted. A 90- 

day finding does not constitute a status 

review under the Act. In a 12-month 

finding, we will determine whether a 

petitioned action is warranted after we 

have completed a thorough status 

review of the species, which is 

conducted following a substantial 90- 

day finding. Because the Act’s standards 

for 90-day and 12-month findings are 

different, as described above, a 

substantial 90-day finding does not 

mean that the 12-month finding will 

result in a warranted finding. 

References Cited 

A complete list of references cited is 

available on the Internet at http:// 

www.regulations.gov and upon request 

from the Nevada Fish and Wildlife 

Office (see FOR FURTHER INFORMATION

CONTACT). 

Authors 

The primary authors of this notice are 

the staff members of the Nevada Fish 

and Wildlife Office (see FOR FURTHER

INFORMATION CONTACT). 

Authority 

The authority for this action is the 

Endangered Species Act of 1973, as 

amended (16 U.S.C. 1531 et seq.). 

Dated: March 29, 2011. 

Rowan W. Gould, 

Acting Director, U.S. Fish and Wildlife 

Service. 

[FR Doc. 2011–8824 Filed 4–12–11; 8:45 am] 

BILLING CODE 4310–55–P 


srobinson on DSKHWCL6B1PROD with PROPOSALS