Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition to List the Sand Mountain Blue Butterfly as Threatened or Endangered with Critical Habitat, 44988-44993 [E6-12577]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 71, Number 152 (Tuesday, August 8, 2006)]
[Proposed Rules]
[Pages 44988-44993]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-12577]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17


Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition to List the Sand Mountain Blue Butterfly as Threatened or 
Endangered with Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day 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 the Sand Mountain blue butterfly 
(Euphilotes pallescens arenamontana) as threatened or endangered under 
the Endangered Species Act of 1973, as amended (Act). We find that the 
petition presents substantial information indicating that listing the 
Sand Mountain blue butterfly may be warranted. Therefore, with the 
publication of this notice, we are initiating a status review of the 
species, and we will issue a 12-month finding to determine if the 
petitioned action is warranted. To ensure that the status review of the 
Sand Mountain blue butterfly is comprehensive, we are soliciting 
scientific and commercial data regarding this species. A determination 
on critical habitat will be made if and when a listing action is 
initiated for this species.

DATES: The finding announced in this document was made August 8, 2006. 
To be considered in the 12-month finding for this petition, comments 
and information should be submitted to us by October 10, 2006.

ADDRESSES: Data, information, comments, or questions concerning this 
petition and our finding should be submitted to the Field Supervisor, 
Nevada Fish and Wildlife Office, U.S. Fish and Wildlife Service, 1340 
Financial Boulevard, Suite 234, Reno, NV 89502 or via electronic mail 
at sandmtblue@fws.gov. The petition is available at https://www.fws.gov/
nevada/nv_species/sand_blue.html. The petition, supporting data, and 
comments will be available for public inspection, by appointment, 
during normal business hours at the above address.

FOR FURTHER INFORMATION CONTACT: Robert D. Williams, Field Supervisor, 
Nevada Fish and Wildlife Office (see ADDRESSES) (telephone 775/861-
6300; facsimile 775/861-6301).

SUPPLEMENTARY INFORMATION:

Public Information Solicited

    When we make a finding that substantial information is presented to 
indicate that listing a species may be warranted, we are required to 
promptly commence a review of the status of the species. To ensure that 
the status review is complete and based on the best available 
scientific and commercial information, we are soliciting information on 
the Sand Mountain blue butterfly. We request any additional 
information, comments, and suggestions from the public, other concerned 
governmental agencies, Tribes, the scientific community, industry, or 
any other interested parties concerning the status of the Sand Mountain 
blue butterfly. We are seeking information regarding the species' 
historical and current status and distribution, its biology and 
ecology, ongoing conservation measures for the species and its habitat, 
and threats to the species and its habitat.
    If we determine that listing the Sand Mountain blue butterfly is 
warranted, it is our intent to propose critical habitat to the maximum 
extent prudent and determinable at the time we would propose to list 
the species. Therefore, we also request data and information on what 
may constitute physical or biological features essential to the 
conservation of the species, where these features are currently found, 
whether any of these areas are in need of special management, and 
whether there are areas not containing these features, which of 
themselves, might be essential to the conservation of the species. 
Please provide specific comments as to what, if any, critical habitat 
should be proposed for designation, if the species is proposed for 
listing, and why that proposed habitat meets the requirements of the 
Act.
    If you wish to comment or provide information, you may submit your 
comments and materials concerning this finding to the Field Supervisor 
(see ADDRESSES).
    Our practice is to make comments and materials provided, including 
names and home addresses of respondents, available for public review 
during regular business hours. We will not consider anonymous comments 
and we will make all comments available for public inspection in their 
entirety. Comments and materials received will be available for public 
inspection, by appointment, during normal business hours at the address 
listed in the ADDRESSES section.

Background

    Section 4(b)(3)(A) of the Endangered Species Act of 1973, as 
amended (16 U.S.C. 1531 et seq.), requires that we make a finding on 
whether a petition to list, delist, or reclassify a species presents 
substantial scientific or commercial information to indicate that the 
petitioned action may be warranted. We base this finding on information 
provided in the petition and information otherwise available in our 
files at the time of petition review. To the maximum extent 
practicable, we make this finding within 90 days of our receipt of the 
petition, and publish our notice of this finding promptly in the 
Federal Register.
    Substantial information, as defined by 50 CFR 424.14(b), 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 information was presented, we 
are required to promptly commence a review of the status of the 
species, if one has not already been

[[Page 44989]]

initiated under our internal candidate assessment process.
    In making this finding, we relied on information provided by the 
petitioners and information otherwise available in our files at the 
time of petition review and evaluated that information in accordance 
with 50 CFR 424.14(b). Our process in making this 90-day finding under 
section 4(b)(3)(A) of the Act and section 424.14(b) of our regulations 
is limited to a determination of whether the information in the 
petition meets the ``substantial information'' threshold.

Petition

    On April 23, 2004, we received a formal petition, dated April 23, 
2004, from the Center for Biological Diversity, Xerces Society, Public 
Employees for Environmental Responsibility, and the Nevada Outdoor 
Recreation Association requesting that the Sand Mountain blue butterfly 
(Euphilotes pallescens arenamontana) known only from Sand Mountain, 
Nevada, be listed as threatened or endangered in accordance with 
section 4 of the Act, and that critical habitat be designated for the 
species concurrent with the listing. The petition is available at 
https://www.fws.gov/nevada/nv_species/sand_blue.html.
    Action on this petition was precluded by court orders and 
settlement agreements for other listing actions that required nearly 
all of our listing funds for fiscal years 2004 and 2005. On September 
26, 2005, we received a 60-day notice of intent to sue, and on January 
5, 2006, we received a complaint regarding our failure to carry out the 
90-day finding on the petition to list the Sand Mountain blue 
butterfly. On April 20, 2006, we reached an agreement with the 
plaintiffs to submit to the Federal Register a completed 90-day finding 
by July 28, 2006, and to complete, if applicable, a 12-month finding by 
April 26, 2007 (Center for Biological Diversity et al. v. Norton, and 
U.S. Fish and Wildlife Service, (CV-00023-LKK-GGH) (E.D. Cal)).

Species Information

    The Sand Mountain blue butterfly was first described as Euphilotes 
pallescens subspecies arenamontana by Austin in 1998 (1998, pp. 556-
557). Prior to the 1998 publication, it had been considered an 
undescribed subspecies of Euphilotes rita, the name under which it was 
previously assigned a Federal category 2 candidate status (see Previous 
Federal Action section).
    The Sand Mountain blue butterfly is a small, pale-blue butterfly in 
the family Lycaenidae. Males have a wingspan that ranges from 10.0 to 
11.8 millimeters (mm) (0.39 to 0.46 inches (in)) and averages 11.1 mm 
(0.44 in). The dorsum is pale bluish-violet, often whitish distally, 
with a narrow (0.5 mm (0.002 in)) black outer margin. There is usually 
a series of dots on the hindwing, but sometimes no more than a terminal 
line on the forewing. There is usually an indistinct pinkish to pale 
orange aurora of moderate width on the posterior hindwing. At the vein 
tips on the posterior of both wings, there are fringes of white with 
indistinct grey checkering. The bottom surface of the male abdomen is 
chalky white. Macules (patches of different coloration) are small, 
often nearly obsolete on the hindwing. Females have a wingspan that 
ranges from 10.0 to 11.9 mm (0.39 to 0.46 in) with an average of 10.9 
mm (0.43 in). The female dorsum is brown to tan, and usually pale 
bluish-gray basally on both wings. The forewing has a faint brown cell-
end bar, while the hindwing has marginal dots. The forewing apex is 
usually whitish. The hindwing aurora is pale orange to pale pink 
usually grading to nearly white distally and not strongly contrasting. 
The female venter and fringes are similar to those of the male (Austin 
1998, p. 556).
    The Sand Mountain blue butterfly is the palest of all Euphilotes. 
The ground color of both sexes is considerably paler than that of E. 
pallescens ssp. pallescens. The pinkish aurora is unlike any other 
Euphilotes. The pale bluish-gray wing bases of the female do not 
contrast with the distal area of the wing as they do on E. pallescens 
ssp. pallescens. The black macules of E. pallescens ssp. arenamontana 
tend to be smaller than those of E. pallescens ssp. pallescens (Austin 
1998, p. 557).
    The Sand Mountain blue butterfly is known only from Sand Mountain, 
Churchill County, Nevada, where it is dependent on its host plant, 
Kearney buckwheat (Eriogonum nummulare) (Austin 1998, p. 557), a long-
lived, perennial shrub with numerous branches (Reveal 2002, p. 1), that 
occurs in scattered locations in several western States (Welsh et al. 
1987, p. 547). Kearney buckwheat typically occurs at Sand Mountain as a 
dominant or co-dominant with other shrubs on less active, smaller dunes 
around the periphery of the main dune (The Nature Conservancy 2002, p. 
1). Because of the small size of the Sand Mountain blue butterfly and 
the frequent high winds typical of the Sand Mountain area, it is likely 
that adult butterflies spend most of their life sheltered within the 
canopy of Kearney buckwheat plants (Murphy 2006). Kearney buckwheat is 
the sole food source for the larvae and an important nectar source for 
adults during their flight period. The butterfly has one brood from 
mid-July to mid-September (Austin 1998, p. 557), a period that 
coincides with the peak flowering period of the Kearney buckwheat 
(Reveal 2002, p. 2).

Previous Federal Action

    We added the Sand Mountain blue butterfly as Euphilotes rita ssp. 
to our list of candidate species as a category 2 candidate species on 
November 21, 1991 (56 FR 58829). 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 was needed to support the preparation 
of a proposed rule. It remained a category 2 candidate as Euphilotes 
rita ssp. in our 1994 Candidate Notice of Review (November 15, 1994; 59 
FR 59020). In the 1996 Candidate Notice of Review (February 28, 1996; 
61 FR 7596), we discontinued the use of category 2 candidates. The Sand 
Mountain blue butterfly has no Federal regulatory status under the Act.

Threats Analysis

    Pursuant to section 4 of the Act, we may list a species, 
subspecies, or distinct population segment of invertebrate taxa on the 
basis of any of the following five factors: (A) Present or threatened 
destruction, modification, or curtailment of habitat or range; (B) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence. In making this finding, we evaluated 
whether threats to the Sand Mountain blue butterfly presented in the 
petition may pose a concern with respect to its survival. The Act 
identifies the five factors to be considered, either singly or in 
combination, to determine whether a species may be threatened or 
endangered. Our evaluation of these threats, based on information 
provided in the petition, is presented below.

A. Present or Threatened Destruction, Modification, or Curtailment of 
the Species' Habitat or Range

    The petition states that the Sand Mountain blue butterfly is known 
only from Sand Mountain in Churchill County, Nevada, where it is 
dependent on its larval host plant, Kearney buckwheat (Eriogonum 
nummulare) (Austin 1998). The petitioners note that while the Kearney 
buckwheat is widespread in Nevada and also occurs

[[Page 44990]]

in Utah, Arizona, and California, several reconnaissance surveys have 
been conducted of sand dunes within 62.5 mile (mi) (100 kilometer (km)) 
radius of Sand Mountain in search of populations of Kearney buckwheat 
large enough to support a population of the butterfly. No Kearney 
buckwheat plants have been observed on any of these surveys, and the 
surveyors concluded that if the plant were present, its population is 
so small that it would not provide suitable habitat for the Sand 
Mountain blue butterfly. The petition relies on communication from a 
species expert, Claudia Funari of the U.S. Bureau of Land Management 
(BLM) to further state that no other habitat exists within the flight 
range of the butterfly. In our files we have an electronic message 
which corroborates this claim (Funari 2004). Furthermore, information 
from our files indicates that butterflies of the family Lycaenidae are 
known to have limited dispersal distances (Arnold 1983, Peterson 1994 
as cited in Peterson 1996). While in some cases they may employ a 
stepping-stone method of hopping to habitat patches, increasing the 
likelihood of dispersing further and expanding their range, the 
petitioners have provided substantial survey information indicating no 
populations of the host plant or the Sand Mountain blue butterfly occur 
within a 62.5 mi (100 km) radius of Sand Mountain. Thus, it is unlikely 
given their life history, ecology, and dispersal capabilities that the 
Sand Mountain blue butterfly would be found beyond this distance.
    The petition claims that the Sand Mountain blue butterfly occurs 
only within the Sand Mountain Recreation Area (SMRA), a BLM designation 
that encompasses 4,795 acres (ac) (1,940 hectares (ha)), and, according 
to the petitioners, is about 1.0 mi (1.6 km) wide and 3.5 mi (5.6 km) 
long. It notes, however, that Kearney buckwheat, the larval host plant 
on which the butterfly depends, has a patchy distribution and much of 
the area is open sand. The petition includes a map as Figure 4 that 
shows dune shrub habitat extending onto BLM lands adjacent to the 
designated boundary of the SMRA (BLM 2003). The petitioners claim that 
the Sand Mountain blue butterfly is dependent on 1,000 ac (405 ha) of 
Kearney buckwheat habitat is supported by a report referenced in the 
petition that states that between 1,000 ac (405 ha) and 1,600 ac (647 
ha) of dune shrub habitat occur inside and outside the SMRA (BLM 2004). 
This dune shrub habitat is comprised of 13 shrub species, one of which 
is the Kearney buckwheat (BLM 2004).
    The petitioners present data in Figure 9, provided to them by BLM, 
that documents an increase in annual visitor use at the SMRA from about 
16,000 persons in 1981 to over 40,000 persons in 2003 (BLM 2003). The 
petition notes that as early as 1985, motorized recreation by 
motorcycles, four wheel drive vehicles, three wheelers, and dune 
buggies accounted for over 90 percent of the total visits to the SMRA 
(BLM 1985). The 2003 BLM data provided by the petitioners also show an 
increase in route proliferation from about 20 mi (32 km) of off-road 
vehicle trails in 1981 to about 200 mi (320 km) in 2003. The petition 
includes four figures (maps) that document the proliferation of the 
route system based on a BLM analysis of satellite imagery from 1978, 
1994, 1999, and 2002 (BLM 2003). In addition to the overall 
proliferation of off-road vehicle routes documented by the imagery, the 
maps clearly show an increase in the amount of habitat fragmentation 
and an expansion of the off-road vehicle route system from the more 
accessible southern end of the main dune into shrub habitat toward the 
north and northeast that had been relatively undisturbed as recently as 
1994. Thus, while about 1,000 ac (405 ha) of potential butterfly 
habitat may remain, an estimated reduction in habitat of about 50 
percent based on our visual comparison of 1978 and 2002 satellite 
imagery, much of this remaining habitat is highly fragmented by the 
extensive trail system that has been created. Furthermore, the off-road 
vehicle use that has led to this reduction in and fragmentation of 
habitat continues to this day and poses an ongoing threat to the 
viability of the Sand Mountain blue butterfly.
    The petition also cites observations over the past 25 years noting 
the effects of off-road vehicles on the Sand Mountain dune shrub 
habitat and, in particular, on the Kearney buckwheat. These include: 
(1) A letter documenting the extirpation of all plant life from an area 
150 ft (46 m) wide along the edge of the main dune over a period of 
several years (Giuliani 1977); (2) a memorandum reporting that up to 
half of 58 individual Kearney buckwheat plants inspected on the south 
side of the mountain had been crushed and broken off at the ground 
surface and were either dead or in the process of resprouting from the 
rootstocks (USFWS 1994); (3) a report to the Service from a research 
scientist at the University of Nevada, Reno (Brussard 1995 (cited 
incorrectly as Brussard 1996 in the petition)) stating that a continued 
decline of the Kearney buckwheat in the overall area could call into 
question the continued existence of the butterfly; and (4) an 
assessment by The Nature Conservancy (2002) that determined the 
condition of the dunes to be heavily impaired due to loss of vegetative 
cover from recreational use and abuse. The petition notes that in this 
assessment, The Nature Conservancy found that running vehicles at high 
speeds over large perennial plants, in particular, was a significant 
source of stress to the Sand Mountain dune system. The petitioners note 
that Kearney buckwheat plants are intentionally targeted because they 
accumulate sand at their base, thereby forming natural jumps. We have 
determined that the report to the Service cited as Brussard (1995) 
actually states ``as long as the foodplant remains as abundant as it is 
now in the overall dune area, we saw no particular threat to the 
continued existence of the butterfly.'' However, despite the inaccurate 
characterization of this letter in the petition, the statement does 
imply that should the abundance of Kearney buckwheat decline, a 
circumstance for which the petitioners have provided significant 
evidence, the loss of this critical foodplant would be a threat to the 
continued existence of the butterfly.
    The petition also provides numerous citations from scientific 
literature that document the effects of off-road vehicles on 
terrestrial habitats in arid environments, including sand dunes. The 
effects include the elimination of a tiger beetle that was once 
widespread and abundant along beaches (Black and Vaughn 2003); 
significant reductions in the number, density, and cover of plants, 
including shrubby perennials (Bury and Luckenbach 1983); and direct 
impacts on desert vegetation (Stebbins 1995; Lathrop 1983; Lathrop and 
Rowlands 1983). Documentation also indicates that natural recovery 
rates of perennial vegetative cover damaged by off-road vehicles in 
arid environments can take decades and, in some cases, may require 
centuries (Lathrop and Rowlands 1983; Kockelman 1983; Webb and Wilshire 
1983).
    None of these citations provides specific evidence of a direct 
significant threat to the Sand Mountain blue butterfly. The papers by 
Bury and Luckenbach (1983, pp. 211-213), Lathrop (1983, pp. 157-164), 
Lathrop and Rowlands (1983, pp. 138-141, 144-146), and Stebbins (1995, 
pp. 471-472), however, do provide documentation that off-road vehicles 
can damage and destroy plants, and result in significant decreases in 
plant numbers, density, and cover of plants, including shrubby

[[Page 44991]]

perennials at various sites in the western North American deserts.
    The papers by Lathrop and Rowlands (1983, p. 143) and Kockelman 
(1983, p. 3) also provide a timeframe for understanding natural 
recovery rates of habitats damaged by off-road vehicle use in arid 
environments. Recovery of damaged vegetation is a process of critical 
importance to the Sand Mountain blue butterfly because it depends on 
the presence of its host plant, the Kearney buckwheat, on an annual 
basis in order to reproduce. Based on the data provided by the 
petitioners (BLM 2003, 2004), we estimate that the habitat on which the 
Sand Mountain blue butterfly depends has been reduced by as much as 50 
percent over the past 25 years and that, at most, 1,000 ac (405 ha) of 
potential, but highly fragmented, habitat remains. These studies 
provide reliable documentation that even if off-road vehicle use were 
to be eliminated from Sand Mountain, natural recovery of the Kearney 
buckwheat habitat may take decades, a time frame that poses an indirect 
threat to the long-term viability of a species that must reproduce 
annually.
    The petition also claims that off-road vehicles alter the hydrology 
of dune systems by exposing clay layers that create an impermeable 
barrier to the percolation of precipitation into the soil. Further 
vehicle impacts break the clay layer and precipitation percolates to 
depths where it is beyond the reach of seedlings attempting to 
establish (Tonenna no date). No data are provided to support this 
claim; therefore, we consider it speculative. The petition also claims 
that constant disruption of the soil surface makes it difficult or 
impossible for seeds to germinate. We agree the germination process 
would be made difficult or impossible under frequent disturbance by 
vehicles. The petition claims that this could be the primary reason for 
a reported skew in Kearney buckwheat populations at Sand Mountain 
toward older shrubs. The petition provides no documentation to support 
this claim. The persistence of some plant species may depend on 
episodic years of strong recruitment (Brigham and Thomson 2003, p. 
154). Episodic regeneration was not found to be characteristic of 
several plants studied in the cold deserts of the Great Basin in which 
Sand Mountain is located (West et al. 1979, pp. 384-385). The same 
researchers, however, also found no correlation between plant size and 
plant age, and that plants that appear even-aged because of their 
similar size are often uneven-aged (West et al. 1979, pp. 386). The 
petitioners do not indicate whether this critical aspect of population 
structure was considered.
    We conclude that the petition provides substantial information to 
support the claim that off-road vehicle use at Sand Mountain presents 
direct and indirect threats to the dune shrub habitat with Kearney 
buckwheat on which the Sand Mountain blue butterfly depends. In 
particular, data provided to the petitioners by the BLM (2003) reliably 
documents that within the past 25 years a progressive loss of dune 
shrub habitat, continuing fragmentation of dune shrub habitat, and an 
ongoing expansion of the route system into dune shrub habitat 
previously considered secure for the butterfly has occurred. The data 
presented in the petition document that annual visitor use has more 
than doubled and the route system has expanded from 20 miles (32 km) to 
over 200 miles (320 km) over this time period. The petition presents an 
estimate, based on a personal communication from the BLM (Tonenna, no 
date), that a maximum of about 1,000 ac (405 ha) of dune shrub habitat 
remain, and notes that the Kearney buckwheat, on which the Sand 
Mountain blue butterfly depends, has a patchy distribution within the 
remaining, highly fragmented habitat. The petitioners also reference a 
report that provides reliable information indicating that at the time 
of the petition, an estimated 1,000 to 1,600 ac (405 to 647 ha) of dune 
shrub habitat remained in which Kearney buckwheat is a component (BLM 
2004, p. 4). We estimate, based on the data presented in the petition 
(BLM 2003, 2004), about 50 percent of the dune shrub habitat may have 
been destroyed or altered over this 25-year time span. The off-road 
vehicle use that has led to this reduction in and fragmentation of 
habitat continues to this day and poses a significant and ongoing 
threat to the continued viability of the Sand Mountain blue butterfly.

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

    The petition claims collection by overzealous lepidopterists is a 
potential threat because of the rarity of the Sand Mountain blue 
butterfly. While we have accepted the claim that the Sand Mountain blue 
butterfly occurs only at Sand Mountain, the petition does not provide 
any data to substantiate the claim that the species is threatened by 
collection.

C. Disease or Predation

    The petitioners claim that diseases affecting larval host plants 
and butterflies, and predation by native and introduced wildlife have 
affected other butterfly species with small population sizes, but 
provide no data to support these claims, and note that no information 
on the potential impacts of disease or predation to the Sand Mountain 
blue butterfly is available.

D. Inadequacy of Existing Regulatory Mechanisms

    The petition claims that the BLM has failed to protect habitat for 
the Sand Mountain blue butterfly from excessive off-road vehicle use 
over the past 25 years, and cites a public comment letter on the 1978 
draft SMRA which states concern over the potential impacts to the 
invertebrate fauna of the dune system and notes that the management 
plan fails to adequately take into account biological considerations 
(Hardy 1978).
    The petition also cites a mid-1990s effort by the BLM, the Service, 
and others to assess the status of the Sand Mountain blue butterfly in 
response to a complaint that off-road vehicles were posing a threat to 
its existence by impacting its host plant (Austin 1990). The initial 
outcome of this effort was a determination that no emergency action was 
necessary because, during the course of the assessment, the Kearney 
buckwheat was found to be much more common than previously believed, 
particularly in the northeastern portion of the dune system. Instead, 
the BLM and Service decided to institute a monitoring plan in order to 
avoid an emergency situation in the future (BLM 1995, p. 1). The 
monitoring plan consisted only of establishing permanent photographic 
points. Due to personnel changes in both agencies, monitoring was 
discontinued after a few years. In recent years, the photographic 
points have been revisited and found to reliably document the ongoing 
alteration and destruction of shrub habitat (Tonenna 2006).
    The petition notes that in the Spring of 2002, BLM staff 
recommended that some areas of Sand Mountain be closed to protect the 
Sand Mountain blue butterfly. As a result, a group comprised of BLM and 
Service staff, representatives from conservation and off-road vehicles 
groups, and representatives of the Fallon-Paiute Shoshone Tribe, who 
consider Sand Mountain sacred, proposed that 1,000 ac (405 ha) be 
closed to off-road vehicles while keeping the more popular off-road 
riding areas open. No action was taken on this proposal.
    The petitioners claim that in 2003, the BLM implemented an 
emergency action to protect and restore the sand dune ecosystem that 
included the following

[[Page 44992]]

six main actions: (1) Continue to manage the SMRA under the existing 
off-road vehicle designation; (2) develop programs and practices that 
encourage off-road vehicle users to prevent disturbance of Kearney 
buckwheat habitat within and outside of the SMRA; (3) begin efforts to 
restore and rehabilitate disturbed Kearney buckwheat habitat within and 
outside of the SMRA; (4) identify existing disturbed travel routes 
through the Kearney buckwheat habitat to connect off-road vehicle use 
areas within and outside the SMRA and discontinue off-road vehicle use 
in habitat outside these travel routes; (5) continue scientific 
investigations into the Sand Mountain ecosystem, including studies of 
the natural history of the plants and animals, restoration techniques, 
and monitoring technology; and (6) initiate a revised management plan 
for the Sand Mountain landscape to update the current Recreation Area 
Management Plan, reflecting the increasing amount and variety of uses 
and demands of the area.
    The primary claim that the petitioners make regarding this strategy 
is that compliance with the encouraged off-road vehicle route system is 
voluntary and unenforceable, and therefore ineffective in preventing 
further habitat decline. They cite data from a 2004 BLM report that 
documents noncompliance occurring throughout the area with all routes 
continuing to be used based on 15 weeks of compliance monitoring. 
Impacts to shrub vegetation continued with multiple vehicles riding 
through vegetation despite alternative existing routes nearby that 
avoid vegetation. The petitioners note that Kearney buckwheat plants 
are intentionally targeted because sand accumulates around the base 
forming natural jumps. The report states that educational efforts and 
increased signage are routinely ignored, and, although there does seem 
to have been some level of compliance as a result of the management 
changes, ``there is still significant noncompliance that will likely 
continue the trend of vegetation loss and prevent the rehabilitation of 
the area'' (BLM 2004).
    We have reviewed all of the sources cited in the petition and have 
concluded that they provide substantial information that existing 
regulatory mechanisms may be inadequate to prevent the progressive 
decline of the habitat on which the Sand Mountain blue butterfly 
depends.

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

    The petition claims that invasive plants, and particularly Russian 
thistle (Salsola kali), pose a threat to the Sand Mountain blue 
butterfly because the fuel load it produces when dry increases the 
potential for wildfire. The petitioners also claim that Kearney 
buckwheat is not adapted to resist fire, and fire could kill or 
seriously damage plants since wildfires have not occurred historically 
at Sand Mountain. An increase in Russian thistle, therefore, would 
increase the risk that a fire may occur and habitat for the Sand 
Mountain blue butterfly would be destroyed (Tonnena no date).
    Russian thistle is known to occur at Sand Mountain and, when dried, 
is highly combustible. However, the petition provides no data to 
support the claim that it is so widespread as to constitute a 
significant threat to either the Kearney buckwheat or the Sand Mountain 
blue butterfly. Nor does the petition provide documentation for the 
claim that Kearney buckwheat is not adapted to resist fire. Elsewhere 
in the petition, the petitioners note that Kearney buckwheat has an 
extensive branching caudex from a deep, woody taproot (Reveal 2002). It 
is at least possible that this taproot, buried beneath sand, would 
survive and resprout after fire, as it has been observed to do after 
damage to the above-ground shoots (USFWS 1994). We do not, therefore, 
find the petition to provide substantial information to support the 
claim that invasive plants and/or fire currently pose a significant 
threat to the Sand Mountain blue butterfly.
    In addition, the petition notes that most insect populations 
normally experience large fluctuations in size (Ehrlich 1992; Schultz 
1998), and that weather, predation, and disease may cause annual 
changes of an order of magnitude or more. The petition claims that 
these normal population fluctuations, in combination with habitat 
alteration or loss, can result in population extirpations (Hanski et 
al. 1995) and that, because of its extremely limited geographic area, 
the butterfly is extremely vulnerable to extinction.
    We acknowledge that insect populations may experience normal large 
population fluctuation, although the petition provides no data specific 
to the Sand Mountain blue butterfly. We have previously, under Factor 
C, noted that there is no evidence to support the claim that disease or 
predation are threats to the butterfly. Nor is there any evidence 
presented that the Sand Mountain blue butterfly population fluctuates 
in response to weather. We acknowledge that habitat alteration may 
exacerbate normal population fluctuations, and that this may make the 
Sand Mountain blue butterfly, a species likely to experience large 
population fluctuations (Murphy 2006), more susceptible to extinction. 
There is no evidence provided, however, that this has occurred, or is 
occurring, and therefore we do not find this threat to be substantial.

Finding

    We have reviewed the petition and literature cited in the petition, 
and evaluated that information. On the basis of this review and 
evaluation, we find that the petition does present substantial 
information to indicate that listing the Sand Mountain blue butterfly 
may be warranted. The Sand Mountain butterfly is known only from Sand 
Mountain, Nevada, where it is closely associated with its host shrub, 
the Kearney buckwheat. Adult butterflies, which survive only a few 
weeks, deposit their eggs on the Kearney buckwheat, which is the only 
food for the larvae (caterpillars) that hatch the following spring. 
Larvae likely pass through several stages of molting, emerging larger 
each time, with each stage dependent on the availability of the food 
resource. The final molt results in a pupa which attaches to a twig or 
other surface and from which the adult emerges resource (Scott 1986, p. 
21). The annual continuance of the butterfly population larvae, 
therefore, depends entirely upon this food.
    An estimated 1,000 ac (405 ha) of dune shrub habitat remained in 
2003, an estimated reduction of about 50 percent over the past 25 
years. Moreover, much of this remaining habitat has been highly 
fragmented by over 200 miles (320 km) of off-road vehicle routes. This 
reduction and fragmentation of habitat correlates with a significant 
increase in off-road vehicle recreational use of the area over the same 
time period. Recreational use continues to increase, and all areas of 
the Kearney buckwheat habitat upon which the Sand Mountain blue 
butterfly depends remain open to off-road vehicle use as a result of 
inadequate regulatory mechanisms. The reduction and fragmentation of 
Kearney buckwheat habitat, therefore, represents a direct reduction in 
the food critical to the survival of the larvae and their subsequent 
emergence as reproductive adults. As the food supply diminishes, fewer 
larvae survive and fewer adults are produced, which in turn is likely 
to result in fewer eggs being deposited.

[[Page 44993]]

Over time this will result in smaller and smaller population levels as 
habitat destruction continues. Thus, there is substantial information 
presented in the petition that the reduction in available habitat is 
leading to a decrease in population that will continue over time, thus 
increasing the risk of extinction. Therefore we conclude that the 
petition has presented substantial information that listing may be 
warranted for this species. We will initiate a status review to 
determine whether listing is warranted.
    The petitioners also requested that critical habitat be designated 
for this species. We always consider the need for critical habitat 
designation when listing species. If we determine in our 12-month 
finding that listing the Sand Mountain blue butterfly is warranted, we 
will address the designation of critical habitat at the time of the 
proposed rulemaking.

References Cited

    A complete list of all references cited herein is available, upon 
request, from the Nevada Fish and Wildlife Office (see ADDRESSES).

Author

    The primary author of this notice is the Nevada Fish and Wildlife 
Office (see ADDRESSES).

Authority

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

    Dated: July 28, 2006.
Kenneth Stansell,
Acting Director, U.S. Fish and Wildlife Service.
 [FR Doc. E6-12577 Filed 8-7-06; 8:45 am]
BILLING CODE 4310-55-P