Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the Sand Mountain Blue Butterfly (Euphilotes pallescens ssp. arenamontana) as Threatened or Endangered with Critical Habitat, 24253-24263 [E7-8330]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 72, Number 84 (Wednesday, May 2, 2007)]
[Proposed Rules]
[Pages 24253-24263]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-8330]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition to List the Sand Mountain Blue Butterfly (Euphilotes 
pallescens ssp. arenamontana) as Threatened or Endangered with Critical 
Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce our 
12-month 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). After a thorough 
review of all available scientific and commercial information, we find 
that the petitioned action is not warranted. We ask the public to 
continue to submit to us any new information concerning

[[Page 24254]]

the status of, and threats to, this subspecies. This information will 
help us to monitor and encourage the ongoing management of this 
subspecies.

DATES: The finding announced in this document was made May 2, 2007.

ADDRESSES: Data, information, comments, or questions regarding this 
notice 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. The complete administrative file 
for this finding is available for inspection, by appointment and 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:

Background

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

Previous Federal Action

    We included the Sand Mountain blue butterfly under the name 
Euphilotes rita ssp. as a Category 2 candidate species in our November 
21, 1991 Candidate Notice of Review (CNOR) (56 FR 58829). Category 2 
included taxa for which information in our possession indicated that a 
proposed listing rule was possibly appropriate, but for which 
sufficient data on biological vulnerability and threats were not 
available to support a proposed rule. The Sand Mountain blue butterfly 
remained a Category 2 candidate as Euphilotes rita ssp. in our 1994 
CNOR (November 15, 1994; 59 FR 59020). In the CNOR published on 
February 28, 1996 (61 FR 7596), we adopted a single category of 
candidate species defined as follows: ``Those species for which the 
Service has on file sufficient information on biological vulnerability 
and threat(s) to support issuance of a proposed rule to list but 
issuance of the proposed rule is precluded.'' In previous CNORs, 
species 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 
CNORs. The decision to stop considering Category 2 species as 
candidates was designed to reduce confusion about the status of these 
species, and to clarify that we no longer regarded these species as 
candidates for listing. Since the Sand Mountain blue butterfly was a 
Category 2 species, we no longer recognized it as a candidate species 
as of the February 28, 1996, CNOR (61 FR 7457).
    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, currently recognized as Euphilotes pallescens ssp. 
arenamontana taxonomically, 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 on the Nevada Fish and 
Wildlife Office Web site (go to https://www.fws.gov/nevada/ and click on 
the Nevada Species link, then on Sand Mountain blue butterfly link).
    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. The agreement specified that if our 90-day finding 
concluded that the petition contained substantial information, we would 
complete 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)).
    On August 8, 2006, we published our 90-day finding in the Federal 
Register (71 FR 44988), in which we concluded that the petition 
presented substantial scientific or commercial information to indicate 
that listing the Sand Mountain blue butterfly may be warranted, we 
initiated a status review of the taxon, and we solicited comments and 
information to be provided in connection with the status review by 
October 10, 2006. This notice constitutes our 12-month finding and is 
submitted in fulfillment of the April 20, 2006, stipulated settlement 
agreement.
    On August 18, 2006, we became a signatory to the multi-party Sand 
Mountain Blue Butterfly Conservation Plan (Conservation Plan), which 
became effective September 21, 2006 (Lahontan Valley Environmental 
Alliance (LVEA), 2006). For a further discussion of the Conservation 
Plan, see the ``Conservation Efforts'' section below.

Biology and Distribution

    The genus Euphilotes, in the family Lycaenidae, is comprised of 
five species of small, pale blue butterflies from western North America 
that are distinguished by discrete differences in genitalia (Pratt 
1994, p. 388). The genus is noteworthy for its close relationship with 
the plant genus Eriogonum (wild buckwheat), a genus of about 250 
species of shrubs, subshrubs, and herbs largely from western North 
America (Reveal 2005). Euphilotes taxa are among the most specialized 
of the North American butterflies in host plant adaptations (Pratt 
1988, p. 63). They typically utilize species of Eriogonum for mating, 
obtaining nectar, host searching, and egg laying (Pratt 1994, p. 388). 
Many of the species and subspecies within the genus have highly 
restricted ranges, in part because of this specialized relationship 
with Eriogonum. The larvae (and to some degree the adults) of 
Euphilotes subspecies are known to specialize on the flowers and seeds 
of specific Eriogonum (Pratt 1988, p. 104). This relationship has been 
the subject of several studies on evolution (Shields and Reveal 1988, 
pp. 51-93; Pratt 1988, pp. 1-653; Pratt 1994, pp. 387-416).
    The pale blue butterfly, Euphilotes pallescens, was first described 
by Tilden and Downey in 1955 under the name Philotes pallescens based 
on specimens collected in Tooele County, Utah (Pratt 1988, p. 18; 
Mattoni 1965, pp. 81, 94). Mattoni (1965, p. 94) reduced the taxon to a 
subspecies which he called Philotes

[[Page 24255]]

(=Euphilotes) rita ssp. pallescens, but he only examined a pair of 
specimens collected at the same time as the original collection by 
Tilden and Downey. Mattoni based his taxonomic conclusion on the 
configuration of the male genitalia, which was thought to be the 
primary characteristic distinguishing P. rita from all other members of 
the genus (Mattoni 1965, p. 81; Shields 1977, p. 2), and his opinion 
that ``greater biological meaning arises from a classification based 
upon relationship rather than difference'' (Mattoni 1965, p. 99).
    In the first modern biosystematic analysis of the genus, Pratt 
(1988, 1994) used cladistic analysis, a method of examining taxonomic 
relationships among species using shared derived characteristics 
(features possessed by two or more taxa in common), to assess its 
members of the genus Euphilotes. He compared 79 morphological 
characters and analyzed enzymes (proteins), allelic variation 
(variation in genes coding for same trait), and diapause (period of 
suspended growth or development similar to hibernation) intensity among 
36 taxa of Euphilotes from western North America (Pratt 1988, 1994). 
Based on these analyses, he concluded that Euphilotes pallescens should 
be recognized as a full species (Pratt 1994, pp. 401-402; Pratt and 
Emmel 1998, p. 209). The Sand Mountain blue butterfly was first 
described as Euphilotes pallescens ssp. arenamontana by Austin in 1998 
(1998, pp. 556-557); it is one of seven named subspecies of the pallid 
blue butterfly in Nevada (Murphy et al. 2006, p. 2). Prior to the 1998 
publication of this name, the Sand Mountain blue butterfly had been 
considered a potentially distinct subspecies of Euphilotes rita (Austin 
1985, p. 105), 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 small with pale blue 
coloration. Males have a wingspan that ranges from 10.0 to 11.8 
millimeters (mm) (0.39 to 0.46 inches (in)), with an average of 11.1 mm 
(0.44 in). The dorsum (back) 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 generally 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 gray 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 (back) 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 (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 that of 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 species Euphilotes pallescens is distributed discontinuously 
from southern and central California (east of the Sierra Nevada) 
through the Great Basin of central Nevada and across central and 
southern Utah (Pratt 1994, p. 402; Shields 1977). The subspecies known 
as the Sand Mountain blue butterfly is known only from Sand Mountain, 
Churchill County, Nevada, where it is dependent on its host plant, 
Eriogonum nummulare (Kearney buckwheat) (Austin 1998, p. 557; Shields 
1977, p. 3), a long-lived, perennial shrub with numerous branches 
(Reveal 2002, p. 1), that occurs in scattered sandy locations in 
several western States (Welsh et al. 1993, p. 547). Searches have been 
conducted within 60 miles (mi) (100 kilometers (km)) of Sand Mountain 
in an effort to determine the presence or absence of Kearney buckwheat 
occurrences on sand dunes that might be able to sustain occurrences of 
Sand Mountain blue butterflies; to date, no additional populations of 
Kearney buckwheat have been found (Funari 2004; Caicco 2006a, 2006b). 
Kearney buckwheat was reported in 1981 to occur in small numbers along 
the eastern edge of Blowsand Mountain, which lies about 12 mi (19.2 km) 
southwest of Sand Mountain (The Nature Conservancy 2004), but no plants 
were observed during three reconnaissance surveys in 2003 and 2004 
(Funari 2004). Many butterflies in the family Lycaenidae have very 
limited dispersal distances that revolve intimately around their 
patchily distributed host plants (Peterson 1996, p. 1990). Dispersal of 
the Sand Mountain blue butterfly has not been studied, but in another 
species in the same genus, Euphilotes enoptes, most adults were found 
to move less than 1,640 feet (ft) (500 meters (m)) and their dispersal 
distance rarely exceeded 0.6 mi (1 km) (Arnold 1983 and Peterson 1994, 
as cited in Peterson 1996, p. 1990).
    Isolated sand dunes are common throughout the Great Basin, often 
associated with depositional areas for windborne sediments derived from 
the now dry beds of Pleistocene Epoch lakes; these geologic features 
are referred to as pluvial lakes, indicating their origins during the 
periods of greater precipitation and lower evaporation typical of the 
Pleistocene climate of the Great Basin. Studies of dispersal of the 
sand dune-obligate beetle, Eusattus muricatus, widely distributed 
throughout the Great Basin and Mojave Deserts, have shown that 
populations on dunes separated by approximately 60 mi (100 km) 
generally exchange very few migrants, even among dunes within the same 
pluvial basin (Britten and Rust 1996, p. 651). Based on these data, the 
authors of this study recommended that all dune-obligate populations in 
the Great Basin separated by 60 mi (100 km) or more from the nearest 
dune within the same pluvial lake basin be considered genetically 
isolated (Britten and Rust 1996, p. 651). In fact, taxonomic 
distinctions made within Euphilotes pallescens are generally consistent 
with this approach, with E. p. ssp. calneva described from sand dunes 
in the Honey Lake area of northeastern California and near Sand Pass, 
in adjacent Nevada (Emmel and Emmel, pp. 277-282; Brussard 2006, p. 1; 
Murphy 2006a), and E. p. ssp. ricei, known only from the Silver State 
Sand Dunes, which are north of Winnemucca, Nevada (Austin et al. 2000, 
p. 3; Brussard 2006, p. 1; Murphy 2006a); each of these sand dune areas 
lies within the Lahontan pluvial basin at a minimum distance of about 
120 mi (192 km) from Sand Mountain.
    We conclude that it is highly unlikely that the Sand Mountain blue 
butterfly occurs at other sites within 60 mi (100 km). Areas within 60 
mi (100 km) have been surveyed to various extents with no reported 
observations of the butterfly's host plant, Kearney buckwheat. We also 
conclude that the subspecies is unlikely to be found at sites located 
more than 60 mi (100 km) from Sand Mountain. Any population of 
Euphilotes pallescens found at any sites at distances greater than 60 
mi (100 km) is most likely to be another subspecies of Euphilotes 
pallescens, based on the

[[Page 24256]]

current accepted taxonomy of the species and the likely genetic 
isolation of E. pallescens ssp. arenamontana due to its life history, 
ecology, and limited dispersal ability. Based on satellite imagery used 
to identify dune shrub habitat (BLM 2003, 2004), we estimate that the 
current range of the subspecies is approximately 1000 acres (405 ha), 
within which Kearney buckwheat is scattered in patches and is a 
dominant or co-dominant shrub on approximately 500-600 ac (202-243 ha) 
(BLM 2006b). Thus, while Sand Mountain blue butterflies may be present 
anywhere within their entire 1,000 ac (405 ha) range, only 50 to 60 
percent of this range is thought to have the Kearney buckwheat shrubs 
on which they depend.
    All Euphilotes larvae are believed to diapause by burying into the 
soil 12.7 to 38.1 inches (in) (5 to 15 centimeters (cm)) prior to 
pupation, which may be delayed for up to 6 years depending on climatic 
conditions (Pratt 1988, p. 319). When this period of diapause is 
broken, the pupae begin development and eventually emerge as adults 
from beneath the soil. The ability of larvae to suspend growth for 
varying periods of time may be part of the reason that the genus 
Euphilotes has high genetic diversity (Pratt 1988, pp. 427-428), 
presumably because it increases the likelihood for random mating.
    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 2006a). Males of the genus 
exhibit a type of mate-searching behavior known as patrolling, which 
involves active searching for potential mates (Pratt 1988, p. 371).
    Kearney buckwheat typically occurs at Sand Mountain as a dominant 
or co-dominant with other shrubs on less active, smaller vegetated 
dunes around the periphery of the main dune (The Nature Conservancy 
2004, pp. 24-26). Kearney buckwheat flowers and seeds are the sole food 
source for the larvae (Pratt 1988, p. 64) and an important nectar 
source for adults during their flight period (Murphy et al. 2006, p. 
1).
    The flowering period of the Kearney buckwheat at Sand Mountain 
begins in late June to early July and continues through September 
(Reveal 2002, p. 2). Like many species of wild buckwheat (Meyer 2006), 
individual Kearney buckwheat plants may be in continuous flower for 
well over a month (Caicco 2006c). Individual flowers within a cluster 
bloom in succession so that after the initial bloom, both seeds and 
flowers are present for extended periods (Caicco 2006c).
    The Sand Mountain blue butterfly has one brood from mid July to 
mid-September (Austin 1998, p. 557; Shields 1977, p. 5), a period that 
coincides with the flowering/fruiting period of Kearney buckwheat. 
During the summer of 2006, scientists from the University of Nevada 
initiated a research effort to determine the distributional 
relationship between the butterfly, its host plant, and the dune shrub 
community. Sand Mountain blue butterflies were counted along a 17,061 
ft (5,200 m) transect, with five surveys made between July 15 and 
August 9, 2006 (Murphy et al. 2006, p. 4). The number of Sand Mountain 
blue butterflies counted along the transects increased over the 
duration of the sampling period; because no decline was detected in the 
number of butterflies counted over that time period, researchers were 
unable to determine the precise length of the 2006 flight season 
(Murphy et al. 2006, p. 5 and Figure 2).
    The researchers found that butterflies occurred across the entire 
extent of their study area, although, regardless of the sampling date, 
butterflies were always more abundant in the northeastern portions of 
the study than in the southwestern areas (Murphy et al. 2006, Figure 
2). The researchers reported that ``as the season matured, multiple 
[Sand Mountain blue] butterflies were observed flying around nearly 
every buckwheat plant at nearly every site on nearly every site visit. 
Even individual buckwheat shrubs, which were isolated from others by as 
many as hundreds of meters due to devegetation from vehicle activities, 
were visited by [Sand Mountain] blue butterflies'' (Murphy et al. 2006, 
pp. 5-6).
    The abundance of the butterfly was closely correlated with Kearney 
buckwheat flower phenology and abundance. Early in the flight season, 
many flowers were unopened; flowers sequentially opened as the sampling 
period progressed toward August, although some unopened buds remained 
after sampling was terminated (Murphy et al. 2006, p. 6). Butterfly 
abundance was strongly correlated with both the number of buckwheat 
inflorescences (flowers) and the abundance of the Kearney buckwheat 
itself (Murphy et al. 2006, p. 6 and Figure 6).
    The researchers also found that the abundance of Kearney buckwheat 
varies considerably throughout the dune shrub habitat, with higher host 
plant and butterfly densities in some areas. At a number of their 
sample locations, Kearney buckwheat was the most abundant shrub in the 
dune shrub community (Murphy et al. 2006, p. 6 and Figure 5). The 
buckwheat was usually among the dominant shrub species both along the 
transect itself and within individual plots (Murphy et al. 2006, p. 6 
and Figure 6).
    The scientists made three conclusions from the data they collected 
during the 2006 flight season of the Sand Mountain blue butterfly. 
First, there was a large number of Sand Mountain blue butterflies--
``perhaps hundreds of thousands''--a number ``substantially above a 
level that would indicate a need to carry out in situ or other actions 
to enhance population size above a critical minimum'' (Murphy et al. 
2006, p. 7). Second, the butterfly appears to co-occur with its host 
plant across the entirety of the shrub's range at Sand Mountain, and 
the habitat quality for the butterfly increases in parallel with the 
shrub density from southwest to northeast across the site (Murphy et 
al. 2006, pp. 7-8). Third, the Kearney buckwheat occurs in a dune shrub 
community with abundant Atriplex canescens (four-wing saltbush) at 
lower elevations that transitions into a community with a more diverse 
assemblage of shrub species at higher elevations (Murphy et al. 2006, 
Figure 5). Along this gradient, the abundance of the Kearney buckwheat 
and, therefore, the density of butterflies varied in parallel (Murphy 
et al. 2006, p. 8).

Conservation Efforts

    On August 18, 2004, the Lahontan Valley Environmental Alliance 
(LVEA), at the request of its board of directors, initiated a public 
planning effort to develop a conservation plan for the Sand Mountain 
blue butterfly. The LVEA was created in 1993 by an agreement among 
local governments and agencies to educate the public and coordinate 
efforts to protect the natural resources and agricultural-based economy 
of the communities in Churchill County. Over the past 13 years, the 
LVEA has worked with various interests to build knowledge and to 
improve communications among the communities, stakeholder groups, local 
governments, and State and Federal agencies involved in, or affected 
by, the natural resources issues of the region (LVEA 2006, p. 1).
    Through the public planning effort described above, the LVEA 
organized and facilitated a working group to identify and address the 
needs of the Sand Mountain blue butterfly. This working group met 
regularly over the subsequent 21 months. In accordance

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with the Nevada Open Meeting Law (Nevada Revised Statute, Chapter 241), 
all meetings were open to the public and noticed in advance with 
agendas posted in public facilities (Nevada Open Meeting Law Manual 
2005). Meeting notes are posted on the LVEA Web site (go to https://www.lvea.org/workgrp.htm and click on the link for this species and 
then click on the link for meeting notes). Participants in the working 
group included representatives from the LVEA, the Bureau of Land 
Management (BLM), the Service, the City of Fallon, Churchill County, 
the Fallon Paiute Shoshone Tribe (Tribe), the Friends of Sand Mountain 
(FOSM), the California Off-Road Vehicle Association (CORVA), the United 
States Naval Air Station Fallon, and private citizens (LVEA 2006, pp. 
1-2).
    The purpose of this effort was to develop a Conservation Plan to 
provide long term protection for the Sand Mountain blue butterfly and 
its habitat, particularly, its host plant, Kearney buckwheat (Eriogonum 
nummulare). Final agreement on the Conservation Plan was reached on May 
3, 2006, and it was signed by representatives of the BLM, the Service, 
the Tribe, CORVA, FOSM, and Churchill County in August and September, 
2006. The Conservation Plan identifies specific actions that are 
necessary to: (1) Eliminate or reduce known threats, (2) incorporate 
species conservation measures into planning and management activities, 
(3) educate permittees and recreation users, and (4) monitor species 
status trends and habitat quality and requirements.
    A designated route system, a conservation action identified in the 
Conservation Plan (LVEA 2006, pp. 14-19), has been implemented by the 
BLM at Sand Mountain to protect the habitat of the Sand Mountain blue 
butterfly from further damage and destruction by off-road vehicles (72 
FR 12187, March 15, 2007). We used criteria specified in our Policy for 
Evaluation of Conservation Efforts When Making Listing Decisions (PECE) 
(68 FR 15100-15115, March 28, 2003) to evaluate the certainty of 
effectiveness of this designated route system and determined there is a 
high level of certainty of effectiveness of the designated route 
system; consequently, we can consider this action in making a 
determination as to whether the Sand Mountain blue butterfly meets the 
Service's definition of a threatened or endangered species (Service 
2007).

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
at 50 CFR Part 424 set forth procedures for adding species to the 
Federal List of Endangered and Threatened Wildlife. In making this 
finding, we summarize below information regarding the status of this 
species in relation to the five factors provided in section 4(a)(1) of 
the Act. In making our 12-month finding, we have considered and 
evaluated all scientific and commercial information in our files, 
including relevant information received during the comment period that 
ended October 10, 2006 (71 FR 44988).

Factor A: The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

    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 (Austin 1998). The entire Sand Mountain dune 
system is estimated to extend over 2,581 ac (1,044 ha), but Kearney 
buckwheat is not evenly distributed throughout this entire area; 
Kearney buckwheat plants are typically found on peripheral, more 
vegetated dunes, and are particularly common on the smaller dunes to 
the northeast of the main dune (BLM 2006a, Map 1). In most areas, 
Kearney buckwheat is a component of a diverse dune shrub habitat 
comprised of up to 13 shrub species (BLM 2004). An estimated 1,000 ac 
(405 ha) of dune shrub habitat with varying amounts of Kearney 
buckwheat existed in 2003 (BLM 2006b, p. 2). The current distribution 
of the shrubs, as described above, reflects both their natural 
adaptation to specific site conditions and the cumulative effect of 25 
years of off-road vehicle use.
    A portion of the Sand Mountain dune system lies within the Sand 
Mountain Recreation Area (SMRA), a BLM designation that encompasses 
4,795 ac (1,940 ha), and is about 1.0 mi (1.6 km) wide and 3.5 mi (5.6 
km) long. The specific BLM designation of the SMRA for recreational use 
does not limit off-road or other forms of recreation only to this area. 
Furthermore, the BLM designation restricts non-recreation type 
activities, such as mineral mining, from occurring within the boundary 
of the designation.
    The recreational use designation for the SMRA was first established 
in 1968 (BLM 1985, p. 4). By 1973, recreational use had reached 32,254 
visitors annually (BLM 1985, p. 5). The first approved management plan 
for the area was developed more than a decade later (BLM 1985). Based 
on BLM information, we estimate that 40 percent, or 400 ac (162 ha) of 
the total of 1,000 ac (405 ha), of the Kearney buckwheat habitat occurs 
within the designated boundary of the SMRA (BLM 2006a, Map 1). The 
remaining estimated 60 percent of the Kearney buckwheat habitat occurs 
on BLM land outside of the eastern SMRA boundary. Until recently, off-
road vehicle use was limited on only about 40 ac (16 ha) of the SMRA; 
no Kearney buckwheat plants occur in this limited-use area. The rest of 
the SMRA was open to unrestricted off-road vehicle use, as were all 
adjacent areas of the dune system.
    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). Annual visitor use 
at the SMRA increased from about 16,000 persons in 1981 to about 65,000 
persons in 2005 and was expected to increase again in 2006 (BLM 2006c). 
Visitation tends to peak on holiday weekends; for example, more than 
5,000 people were present over the Labor Day weekend in 2006 (Nevada 
Appeal 2006, p. 1). In recent years, however, there has been a pattern 
of increased use on non-holiday weekends (BLM 2006c).
    The BLM's Carson City Field Office has documented the expansion of 
an off-road vehicle route system based on an analysis of satellite 
imagery from 1978, 1994, 1999, and 2002; the route system has grown 
from about 20 mi (32 km) of off-road vehicle trails in 1981 to about 
200 mi (320 km) in 2003 (BLM 2003). In addition to documenting the 
overall proliferation of off-road vehicle routes, the imagery clearly 
shows 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 dune shrub habitat adjacent to the 
SMRA toward the north and east that had been relatively undisturbed as 
recently as 1994 (BLM 2003).
    Based on the trail proliferation visible in the satellite imagery 
from 1978 to 2003 (BLM 2003, 2004), we estimate that the shrub habitat 
on which the Sand Mountain blue butterfly depends may have been reduced 
by as much as 50 percent over the past 25 years. At most, 1,000 ac (405 
ha) of dune shrub habitat remains, and within that area 500 ac (202 ha) 
to 600 ac (243 ha) may have Kearney buckwheat as a dominant or co-
dominant shrub (BLM 2006c). We consider the entire 1,000 ac (405 ha) of 
dune shrub habitat to be the current range of the Sand Mountain blue 
butterfly; this includes non-Kearney buckwheat habitat through which 
the species passes, including areas devoid

[[Page 24258]]

of vegetation such as trails, as well as areas that support the Kearney 
buckwheat shrubs on which the butterfly depends for completion of its 
life cycle. Because the amount of Kearney buckwheat within a patch of 
dune shrub habitat varies, no precise data on the total number of 
individual Kearney buckwheat shrubs is available. We also have no 
reliable estimate of the historical distribution of the Kearney 
buckwheat at Sand Mountain other than an anecdotal report of a minor 
amount of vegetation having been lost along the periphery of the dune 
(Guiliani 1977); therefore, we consider the existing estimate of 1,000 
ac (405 ha) of dune shrub habitat to approximate the historic range of 
the Sand Mountain blue butterfly.
    The Sand Mountain dune system was included in an initial 
conservation assessment of blowing sand mountains prepared by The 
Nature Conservancy (2004). This conservation assessment ranked the 
long-term (defined as greater than 100 years) viability of the Sand 
Mountain dune ecosystem based on size, condition, and landscape 
context, using information from the existing literature and expert 
opinion (The Nature Conservancy 2004, p. 29). Each of these factors had 
the potential to be ranked as very good, good, fair, or poor based on 
specific viability criteria (The Nature Conservancy 2004, p. 35). Size 
was ranked as good if there was 1,236 ac-2,471 ac (500-1,000 ha) of 
connected habitat outside of the area heavily affected by off-road 
vehicle use (The Nature Conservancy 2004, p. 35). The condition rank 
was based on three criteria: (1) Whether invasive plants were present 
that could artificially stabilize dune dynamics; (2) whether other 
alterations affecting dune mobility, such as vegetation mortality or 
artificial mobilization of stable sands, were occurring; and (3), 
whether there was natural recruitment by key plant species. The 
condition was assigned a fair rank based on the fact that only the 
criterion regarding the presence of invasive plants was met (The Nature 
Conservancy 2004, p. 35). The landscape context was ranked very good 
based on the fact that the connection to the current sand source 
remained intact (The Nature Conservancy 2004, p. 35). Overall, the 
long-term viability of the Sand Mountain dune system was ranked 
marginally good, but it was noted that the ``rapid trend towards an 
increasingly degraded condition of this area is of considerable 
concern'' (The Nature Conservancy 2004, p. 35). The assessment noted 
that the condition of the area was primarily affected by off-road 
vehicle use, which was of particular concern because of the small 
overall size of the area and the likelihood of increasing use levels at 
the SMRA (The Nature Conservancy 2004, p. 36). It should be emphasized 
that this ranking was for the Sand Mountain dune ecosystem as a whole 
and none of the viability criteria evaluated specifically addressed 
either the status of the Sand Mountain blue butterfly or the Kearney 
buckwheat. The relevance of this report to the dune shrub habitat lies 
in its assessment that the process that supplies the source of sand to 
the ecosystem remains intact, and the corroboration that it provides of 
the threats posed by off-road vehicles and invasive weeds.
    There have been several observations over the past 25 years on the 
effects of off-road vehicles on the Sand Mountain dune shrub habitat, 
on the Kearney buckwheat, and on the relationship between the buckwheat 
habitat and the Sand Mountain blue butterfly. 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 from the Service to the BLM 
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 (Service 1994); (3) a mid-1990's report 
to the Service from a research scientist at the University of Nevada, 
Reno, stating that ``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'' (Brussard 1995).
    In our 90-day finding on the petition to list the Sand Mountain 
blue butterfly (71 FR 44988, August 8, 2006), we concluded that the 
petition provided substantial information to support the assertion 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, we based our 
conclusion on the following--data provided by the petitioners that 
reliably documented a progressive loss of dune shrub habitat within the 
past 25 years, continuing fragmentation of dune shrub habitat, and an 
ongoing expansion of the route system into dune shrub habitat 
previously considered secure for the butterfly (BLM 2003); data that 
documents annual visitor use has more than doubled and the route system 
has expanded from 20 mi (32 km) to over 200 mi (320 km) over this time 
period (BLM 2003); an estimate that 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); and our estimate, based on satellite 
imagery prepared by BLM (2003), that about 50 percent of the dune shrub 
habitat within the species current range may have been destroyed or 
altered over this 25-year time span.
    The scientific literature documents the effects of off-road 
vehicles on terrestrial habitats in arid environments, including sand 
dunes. Effects include 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). While 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) do provide 
documentation that off-road vehicles can damage and destroy plants and 
result in significant decreases in plant numbers, density, and cover, 
including shrubby perennials at various sites in the western North 
American deserts. Specific observations of such impacts at Sand 
Mountain have been reported previously (Guiliani 1977; Service 1994; 
The Nature Conservancy 2004, p. 36; BLM 2006e).
    The scientific literature provides documentation 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). The papers by Lathrop and Rowlands (1983, p. 143) and 
Kockelman (1983, p. 3) provide a timeframe for understanding natural 
recovery rates of habitats damaged by off-road vehicle use in arid 
environments. We previously found that these studies provided 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 timeframe that might pose an indirect threat to the 
long-term viability of an obligate butterfly species that must 
reproduce annually and relies on the buckwheat as a host plant. We now 
have evidence, however, from the first comprehensive assessment of the 
status of the Sand Mountain blue butterfly to indicate that

[[Page 24259]]

a large viable population of the species exists despite the past loss 
of habitat; moreover, the presence of butterflies at even small, 
relatively isolated patches of Kearney buckwheat suggests that the 
butterfly is not particularly sensitive to habitat fragmentation 
(Murphy et al. 2006, pp. 5-6).
    Furthermore, as noted in the Biology and Distribution section, 
since the publication of the 90-day finding, we have obtained new 
information on the abundance and status of the Sand Mountain blue 
butterfly and the potential threats of habitat loss and fragmentation 
to the species. Researchers collected data along several permanent 
transects installed throughout the distribution of the dune shrub 
habitat at Sand Mountain from July 15 through August 9, 2006 (Murphy et 
al. 2006, pp. 4-5). The scientists estimated that hundreds of thousands 
of adult Sand Mountain blue butterflies may have emerged during the 
2006 flight season (Murphy et al. 2006, p. 7). Adult butterflies were 
associated with nearly all Kearney buckwheat shrubs along the transects 
and butterflies were distributed across the entire available habitat 
area, even with individual buckwheat shrubs isolated from others by 
hundreds of meters (Murphy et al. 2006, p. 6).
    The scientists concluded the Sand Mountain blue butterfly numbers 
were ``substantially above a level that would indicate a need to carry 
out in situ or other actions to enhance population size above a 
critical minimum'' (Murphy et al. 2006, p. 7). Annual population 
numbers may vary considerably depending on local weather conditions, 
and the researchers note that the large population in 2006 may 
represent an atypical spike in the butterfly population (Murphy et al. 
2006, p. 9). However, even if this number represents an upper 
population estimate, we believe that the very large number of 
butterflies observed during the recent survey clearly shows that the 
remaining Kearney buckwheat habitat is currently sufficient to support 
a viable population of the Sand Mountain blue butterfly.
    Although sufficient habitat remains to support a robust population 
of the Sand Mountain blue butterfly (Murphy et al. 2006, p. 7), 
researchers have cautioned that ``the sizable Sand Mountain blue 
population notwithstanding, continued degradation of the shrub 
community and losses of Kearney buckwheat will ultimately lead to the 
elimination of the butterfly'' (Murphy et al. 2006, p. 9). To reduce 
the significance of the threat posed to the Sand Mountain blue 
butterfly by continued degradation of the shrub community and losses of 
Kearney buckwheat, on December 12, 2006, the BLM implemented an 
emergency restriction on motorized use on 3,985 ac (1,612 ha) of land 
to prevent further adverse effects on the habitat of the Sand Mountain 
blue butterfly (BLM 2006b); the closure notice was published in the 
Federal Register on March 15, 2007 (72 FR 12187). This action, which 
reduces the route system both within and outside of the SMRA from an 
estimated 200 mi (320 km) to 21.5 mi (34.4 km), has returned the route 
mileage to about the 1980 level. The route designation system adopted 
by BLM is consistent with the Conservation Plan (LVEA 2006) and the 
restrictions are described by BLM as necessary to prevent further 
adverse effects to the habitat of the Sand Mountain blue butterfly (72 
FR 12187). The route designation system is specifically designed to 
reduce threats from recreational use, weed infestation, fire, and the 
reduction of site potential, thereby furthering the objectives of 
eliminating off-road vehicle incursions into dune shrub and butterfly 
habitat; preventing route increases in dune shrub habitat; minimizing 
shrub damage and loss; and allowing for habitat regeneration and 
restoration (LVEA 2006, p. 15). The emergency restriction will remain 
in effect until the Resource Management Plan (RMP) has been updated to 
address the long-term management of the wildlife, cultural, vegetation, 
and recreational resources in the area or until the Field Office 
Manager determines it is no longer needed (BLM 2006b, p. 1; 72 FR 
12187, March 15, 2007). Every indication we have from the BLM at both 
the field office and state office level is that the emergency 
restriction will remain in place until made permanent through an 
amendment to the RMP. The RMP must be updated in compliance with the 
Federal Land Management and Policy Act, the National Environmental 
Policy Act, and other applicable laws and policies which have, among 
other requirements, opportunity for public and agency review and 
comment. Under the terms of the Conservation Plan monitoring of 
compliance with the designated route system will continue and results 
will be reviewed every six months; areas in which non-compliance 
exceeds a specified threshold will be fenced (LVEA 2006, p. 60).
    The Conservation Plan also includes increased law enforcement to 
ensure compliance in the use of the designated route system, especially 
on heavy use weekends and randomly at other times. Through an agreement 
with Churchill County, which is a party to the Plan, local law 
enforcement staff will be used in the camping areas to allow BLM Park 
Rangers to patrol the route system and other areas (LVEA 2006, p. 20). 
Further, any person who fails to comply with the BLM restriction order 
may be subject to imprisonment for not more than 12 months or a fine in 
accordance with the applicable provisions of 18 U.S.C. 3571, or both 
(BLM 2006b, p. 3; 72 FR 12187, March 15, 2007). A handout was given to 
recreational users over Labor Day weekend, 2006, informing them of the 
completion and approval of the Conservation Plan, the upcoming 
mandatory route system, and the importance of demonstrating success in 
protecting the habitat for the Sand Mountain blue butterfly (BLM 
2006d). A variety of additional public education activities are 
provided for in the Conservation Plan, including interpretive, 
cautionary and regulatory signage throughout the SMRA and dune system, 
as well as education pamphlets, brochures, and information available on 
Web sites and other forms of media (LVEA 2006, p. 21-24).
    Implementation of the limited off-road vehicle route system is 
already occurring. We have evaluated the certainty of effectiveness of 
the designated route system using criteria specified in PECE (68 FR 
15115, March 28, 2003). Based on our evaluation, we have determined 
that this conservation action satisfies all of the PECE criteria for 
the certainty of effectiveness (Service 2007). We conclude that the 
off-road vehicle route system is sufficiently certain to be implemented 
and effective so as to have reduced the present and future threat of 
destruction, modification, or curtailment of the habitat or range of 
the Sand Mountain blue butterfly to a level such that off-road vehicle 
impacts to habitat are not a basis for finding that listing is 
warranted.
    Other components of the Conservation Plan have also been initiated 
related to research (LVEA 2006, pp. 27-28). These include mapping of 
current Kearney buckwheat and invasive weeds distribution; remote 
sensing of habitat characteristics, trends, and route analyses; studies 
of the Sand Mountain blue butterfly population status and habitat 
requirements; population dynamics of the Kearney buckwheat; and Kearney 
buckwheat propagation and transplantation studies. Kearney buckwheat 
habitat and invasive weeds mapping and remote sensing analysis of 
habitat characteristics, trends, and route analyses have been in 
progress for several years. The BLM has secured funding through grants 
to purchase additional imagery to continue

[[Page 24260]]

the trend analysis in 2006, 2009, and 2012 (LVEA 2006, p. 28). Research 
on the population status of the butterfly was initiated during the 2006 
adult flight season by scientists from the University of Nevada, Reno, 
with funding through the Nevada Biodiversity Initiative; these data 
provide a baseline against which future fluctuations in the butterfly 
population can be compared (Murphy et al. 2006). Pilot studies of the 
population dynamics of the Kearney buckwheat have been initiated (LVEA 
2006, p. 27), and seed of the Kearney buckwheat has previously been 
collected through the BLM Seeds of Success program. Propagation studies 
using these seeds, and other seeds to be collected on site, are to be 
conducted by the Natural Resource Conservation Service's newly 
established Fallon Plant Materials Center, which will also conduct 
transplantation studies of propagated seedlings into disturbed habitats 
at Sand Mountain (Tonenna 2006). While we did not rely on them making 
this finding, we recognized that these research components will both 
inform and facilitate efforts to recover damaged butterfly habitat at 
Sand Mountain as well as contribute to sound scientific data for future 
management actions.
    In our 90-day finding, we addressed the claim by the petitioners 
that the constant disruption of the soil surface makes it difficult or 
impossible for seeds of the Kearney buckwheat to germinate and for 
seedlings to establish and concluded that the petitioners had provided 
no documentation for this claim (71 FR 44991). The Service has since 
made field visits to Sand Mountain and, while we have no quantitative 
data on this matter, we observed an absence of Kearney buckwheat 
seedlings in areas of high off-road vehicle use. We also observed 
numerous Kearney buckwheat seedlings in areas that received little, if 
any, off-road vehicle use (Caicco 2006c). These observations are 
consistent with previous reports (Tonenna 2003 as cited in The Nature 
Conservancy 2004, p. 37). We believe, based on these observations, that 
the constant disruption of the sand surface in heavily used areas may 
interfere with the establishment of Kearney buckwheat and could 
potentially pose a long-term threat to shrub regeneration and, 
therefore, to the long-term viability of the butterfly itself. However, 
the restriction of off-road vehicle recreation to the designated route 
system substantially reduces the magnitude and imminence of the threat 
to the regeneration of Kearney buckwheat. As described above, 
sufficient habitat remains at Sand Mountain to support a large 
population of the Sand Mountain blue butterfly, and the reduction in 
the level of threat due to the designated route system, over the long-
term, ensures that natural shrub regeneration and/or active restoration 
will maintain sufficient habitat to ensure the viability of the Sand 
Mountain blue butterfly.
    Although not identified as a threat by the petitioners, trampling 
or grazing of buckwheat plants and/or seedlings by livestock was 
identified by the working group as a potential threat to the habitat of 
the butterfly, although it was acknowledged that more information was 
needed to determine the level of threat (LVEA 2006, pp. 11-12). Dune 
shrub habitat with and without Kearney buckwheat occurs within portions 
of two range allotments, where it comprises 1,357 ac (549 ha), or 2 
percent, of the Salt Wells Allotment, and 331 ac (134 ha), or 0.5 
percent, of the Frenchmen Flat Allotment. The stocking values are set 
at 270 cattle and 1,626 animal unit months (AUMS) from October 15 
through April 15 for Salt Wells and 403 cattle and 2,001 AUMS from 
October 15 through April 15 for Frenchmen Flat. We are not aware of any 
evidence that supports trampling or grazing as a significant threat to 
the Kearney buckwheat.
Summary of Factor A
    Biological data on the Sand Mountain blue butterfly collected by 
researchers document that hundreds of thousands may have been present 
during the 2006 adult flight season. These data show that a large, 
robust population of the Sand Mountain blue butterfly remains despite 
the estimated loss of as much as 50 percent of its habitat. The only 
known threat of potential significance in the foreseeable future is the 
destruction by off-road vehicles of the dune shrub habitat containing 
the Kearney buckwheat, upon which the butterfly depends for its 
survival. Habitat destruction is a gradual and cumulative process that 
affects not only mature shrubs, but also likely disrupts their 
reproductive capacity by constant disturbance of the sand surface, 
thereby preventing seedling establishment. The shrubs, however, are 
long-lived and the habitat remains sufficiently extensive such that the 
threat to the butterfly does not cause it to be in danger of extinction 
nor likely to become in danger of extinction in the foreseeable future. 
Further, an emergency restriction on motorized use on 3,985 ac (1,613 
ha) to protect the habitat of the butterfly went into effect on 
December 12, 2006 and a closure notice regarding these restrictions was 
published in the Federal Register on March 15, 2007 (72 FR 12187). The 
implementation of this emergency restriction, and the high level of 
certainty of its effectiveness, has substantially reduced the magnitude 
and significance of any long-term threat posed by off-road vehicles to 
the habitat and viability of the Sand Mountain blue butterfly. 
Therefore, we conclude that the Sand Mountain blue butterfly is not 
now, or in the foreseeable future, threatened by destruction, 
modification, or curtailment of its habitat or range.

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

    We are not aware of any scientific or commercial data that indicate 
overutilization for commercial, recreational, scientific, or 
educational purposes poses a threat to the species.

Factor C: Disease or Predation

    We are not aware of any scientific or commercial data that 
indicates either disease or predation poses a threat to the species.

Factor D: Inadequacy of Existing Regulatory Mechanisms

    In our 90-day finding on the petition to list the Sand Mountain 
blue butterfly, we found that the petitioners had provided substantial 
information that existing regulatory mechanisms may be inadequate to 
prevent the progressive decline of the habitat on which the butterfly 
depends (page 44991 of 71 FR 44988, August 8, 2006). We based our 
determination on evidence that the public had raised the issue of the 
potential impacts of off-road recreational use on the invertebrate 
fauna of the dune system over 25 years ago (Hardy 1978); the inactivity 
of a monitoring plan initiated in the mid-1990's after personnel 
changes in both the BLM and Service; the lack of action on a 2002 
proposed closure of 1,000 ac (405 ha) of dune shrub habitat by a group 
comprised of BLM and Service staff, representatives from conservation 
and off-road vehicle groups, and representatives of the Fallon-Paiute 
Shoshone Tribe; and the lack of compliance with a voluntary route 
system implemented by the BLM in 2004 that was intended to protect and 
restore the sand dune ecosystem.
    The inadequacy of the voluntary off-road vehicle route system is 
well documented in a monitoring report on compliance with the 
encouraged route system for the period 2003-2006 (BLM 2006e). High 
levels of noncompliance occurred from the onset of implementation of 
the voluntary system,

[[Page 24261]]

and the number of incursions into habitat outside of the encouraged 
routes increased in 2006 (BLM 2006e, pp. 3-4). Multiple incursions into 
habitat outside of the encouraged route system typically occurred at 
any given point, so that the cumulative impacts were considered to be 
four times greater than the number of noncompliance points (BLM 2006e, 
p. 6.). BLM's information also indicates a strong relationship between 
the number of visitors and the number of noncompliance points (BLM 
2006e, p. 7). Moreover, about 50 percent of all noncompliance points 
occurred at or near red carsonite posts installed to alert riders that 
travel was discouraged in areas behind the posts (BLM 2006e, p. 8). 
Overall, under the voluntary system 98 percent of all existing routes 
continued to be used and new routes were created, indicating an ongoing 
expansion of habitat degradation with little or no restoration of 
previously degraded areas (BLM 2006e, p. 13).
    On December 12, 2006, the BLM implemented an emergency restriction 
on motorized use on 3,985 ac (1,613 ha) of land to prevent further 
adverse effects on the habitat of the Sand Mountain blue butterfly (BLM 
2006b; 72 FR 12187, March 15, 2007). This action, which reduced the 
route system from an estimated 200 mi (320 km) to 21.5 mi (34.4 km), 
has returned the designated route mileage to about the 1980 level. The 
emergency restriction affects certain public lands within Sections 13, 
14, 16, 21 through 24, 28, 29, 32, and 33, of Township 17 North, Range 
32 East (Mt. Diablo Meridian) (72 FR 12187). This action restricts 
motorized vehicle use to selected existing routes that generally lie on 
the periphery of the Sand Mountain blue butterfly habitat, although 
several existing routes remain open to motorized use that cross between 
existing patches of dune shrub habitat; the designated routes were 
selected to prevent further adverse effects to the habitat of the Sand 
Mountain blue butterfly while maintaining recreational use at the SMRA. 
This action is consistent with the Conservation Plan (LVEA 2006) and is 
specifically designed to address threats from recreational use, weed 
infestation, fire, and the reduction of site potential, thereby 
furthering the objectives of eliminating or reducing the number of off-
road vehicle incursions into dune shrub and butterfly habitat; 
eliminate route increase in dune shrub habitat; eliminate shrub damage 
and loss; and allow for habitat regeneration (LVEA 2006, p. 15). The 
emergency restriction will remain in effect until the Resource 
Management Plan has been updated to address the long-term management of 
the wildlife, cultural, vegetation, and recreational resources in the 
area or until the Field Office Manager determines it is no longer 
needed (BLM 2006b, p. 1; 72 FR 12187, March 15, 2007). Every indication 
we have from the BLM at both the field office and state office level is 
that the emergency restriction will remain in place until made 
permanent through an amendment to the RMP.
    The Conservation Plan also provides for increased law enforcement, 
especially on heavy use weekends and randomly at other times; through 
an agreement with Churchill County, which is a party to the Plan, local 
law enforcement staff will be used in the camping areas to allow BLM 
Park Rangers to patrol the route system and other areas (LVEA 2006, p. 
20). In addition, any person who fails to comply with this restriction 
order may be subject to imprisonment for not more than 12 months or a 
fine in accordance with the applicable provisions of 18 U.S.C. 3571, or 
both (BLM 2006b, p. 3; 72 FR 12187, March 15, 2007). A handout was 
given to recreational users over Labor Day weekend, 2006, informing 
them of the completion and approval of the Conservation Plan, the 
upcoming mandatory route system, and the importance of demonstrating 
success in protecting the habitat for the Sand Mountain blue butterfly 
(BLM 2006d).
    The Conservation Plan includes provisions for regular reporting on 
progress of implementation and effectiveness of various actions taken 
pursuant to the plan (LVEA 2006, p. 30). This includes provisions for 
regularly scheduled meetings of the parties to the plan, at which an 
evaluation of the implementation progress and effectiveness of the plan 
(including the route system and its enforcement) will be reviewed and, 
if necessary, modifications made and adaptive management actions 
initiated. The first meeting of the parties since the closure notice 
was put into effect occurred on March 15, 2007. Implementation progress 
was reviewed, the signage and fencing strategy and funding 
considerations were discussed, and the next meeting was scheduled for 
May 10, 2007. The agenda for the latter meeting will include further 
discussion of the fencing strategy and the scheduling of a site visit 
to discuss fence placement along key route segments. At every six-month 
meeting, the implementation success of the conservation actions will be 
evaluated, the success or failure of the objectives of each strategy 
will be determined and an adaptive management plan will be triggered, 
if appropriate. At annual meetings, the long-term monitoring will be 
analyzed and continuation or modification of the plan will be 
determined, based on the triggers for overall plan success. We note 
also that BLM has demonstrated their commitment to monitor the 
situation and to take appropriate action, as illustrated by BLM's 
adoption of the mandatory route system based on monitoring of the 
voluntary route system that previously was in place.
    As described above (see discussion of Factor A), we reviewed the 
route system in accordance with PECE and found that all of the criteria 
for certainty of effectiveness are met, and concluded there is a high 
level of certainty of effectiveness of the route system (Service 2007). 
We conclude that the emergency restriction on motorized vehicle use has 
established an adequate regulatory mechanism to protect the existing 
Kearney buckwheat habitat which, as noted above, remains sufficient to 
support a large, viable population of the Sand Mountain blue butterfly 
(Murphy et al. 2007, p. 7).
Summary of Factor D
    Unrestricted off-road vehicle recreation at Sand Mountain has been 
the primary cause of the gradual process of destruction and 
modification of the dune shrub habitat of the Sand Mountain blue 
butterfly over the past two decades and remains the only threat of 
potential significance to the species in the foreseeable future. 
However, we have determined that the implementation and effectiveness 
of a mandatory, enforceable route system that restricts travel within 
the dune shrub habitat adequately addresses this potential threat by 
eliminating or greatly reducing further habitat deterioration and 
allowing for habitat recovery within closed areas. We believe that the 
strengthened regulatory approach and increased emphasis on encouraging 
compliance with the mandatory route system has substantially reduced 
the magnitude and imminence of the threat of off-road recreational use 
to the Kearney buckwheat habitat, which currently remains sufficient to 
support a large, viable population of the Sand Mountain blue butterfly. 
Therefore, we have determined that the inadequacy of existing 
mechanisms does not currently constitute a threat to the Sand Mountain 
blue butterfly.

Factor E: Other Natural or Manmade Factors Affecting the Continued 
Existence of the Species

    Several other natural or manmade factors have been identified as 
potential

[[Page 24262]]

threats to the Sand Mountain blue butterfly, including invasive weeds 
(LVEA 2006, p. 10; The Nature Conservancy 2004, pp. 49-52; Murphy et 
al. 2006, p. 7 and Figure 7), wildfire (LVEA 2006, pp. 13-14; Murphy et 
al. 2006, p. 9); climate change (LVEA 2006, p. 14; Murphy et al. 2006, 
p. 9), camping (LVEA 2006, p. 11), hiking (LVEA 2006, p. 14), horseback 
riding (LVEA 2006, p. 14), pollution (LVEA 2006, p. 14), and military 
action (LVEA 2006, p. 14). In addition, in our 90-day petition finding, 
we acknowledged that while large fluctuations in size typical of insect 
populations may make a species with an extremely limited distribution, 
such as the Sand Mountain blue butterfly, more susceptible to 
extinction (Ehrlich 1992), we are aware of no information that large 
population fluctuations have occurred, or are likely to occur for this 
species. (71 FR 44992, August 8, 2006). Although researchers have 
acknowledged that the large population observed in 2006 may have been 
an anomaly, which could have obscured normal patterns of butterfly 
distribution that might suggest a more significant threat to the 
species than is indicated by the 2006 field observation (Murphy et al. 
2006, p. 9), they also concluded that the Sand Mountain blue butterfly 
numbers were ``substantially above a level that would indicate a need 
to carry out in situ or other actions to enhance population size above 
a critical minimum'' (Murphy et al. 2006, p. 7). Based on this 
assessment, we believe that the population will remain viable into the 
foreseeable future.
    Of the potential threats cited above, we consider the interrelated 
factors of invasive weeds and fire to be the most significant. The 
primary invasive weeds of concern at Sand Mountain are Salsola tragus 
(Russian thistle) and Bromus tectorum (cheatgrass). Large patches of 
both species are present in areas along the periphery of the sand 
dunes, principally in areas where livestock water tanks and camping are 
permanently located (LVEA 2006, p. 10). Researchers did not find 
cheatgrass to be a dominant species along transects in 2006 (Murphy et 
al. 2006, Figure 5). The seeds of these invasive weeds can be spread by 
wind, cattle, and off-road vehicle transport (LVEA 2006, p. 11). There 
is no evidence that these annual weeds are capable of artificially 
stabilizing the dune systems at Sand Mountain (The Nature Conservancy 
2004, p. 53), and we do not consider artificial stabilization of the 
dune system to be a significant threat to the habitat of the Sand 
Mountain blue butterfly. We are unable to assess the significance of 
off-road vehicles as a vector for weed transport because of lack of 
data, although they likely facilitate weed establishment through 
surface disturbance.
    Because both cheatgrass and Russian thistle are annual pla