Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Tucson Shovel-nosed Snake as Endangered or Threatened, 56730-56738 [2014-22331]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 79, Number 184 (Tuesday, September 23, 2014)]
[Proposed Rules]
[Pages 56730-56738]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-22331]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2014-0035: 4500030113]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Tucson Shovel-nosed Snake as Endangered or 
Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to list the Tucson shovel-nosed snake 
(Chionactis occipitalis klauberi) as an endangered or threatened 
species under the Endangered Species Act of 1973, as amended (Act). 
After a review of the best available scientific and commercial 
information, we find that listing the Tucson shovel-nosed snake as an 
endangered or threatened species is not warranted, and, therefore, we 
are

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removing this subspecies from our candidate list.

DATES: The finding announced in this document was made on September 23, 
2014.

ADDRESSES: This finding is available on the Internet at https://www.regulations.gov at Docket Number FWS-R2-ES-2014-0035. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Arizona Ecological Services Field Office, 
2321 W. Royal Palm Road, Suite 103, Phoenix, AZ 85021. Please submit 
any new information, materials, comments, or questions concerning this 
finding to the above street address.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, U.S. 
Fish and Wildlife Service, Arizona Ecological Services Field Office, 
2321 W. Royal Palm Road, Suite 103, Phoenix, AZ 85021; telephone 602-
242-0210; facsimile 602-242-2513; email incomingazcorr@fws.gov. If you 
use a telecommunications device for the deaf (TDD), please call the 
Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

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

Previous Federal Actions

    We received a petition, dated December 15, 2004, from the Center 
for Biological Diversity requesting that we list the Tucson shovel-
nosed snake (Chionactis occipitalis klauberi) as an endangered or 
threatened species throughout its range and designate critical habitat 
within its range in the United States. The petition, which was clearly 
identified as such, contained detailed information on the natural 
history, biology, current status, and distribution of the Tucson 
shovel-nosed snake. It also contained information on what the 
petitioner reported as potential threats to the subspecies from urban 
development, agricultural practices, collecting, inadequacy of existing 
regulations, drought, and climate change. In response to the 
petitioner's requests, we sent a letter to the petitioner, dated 
September 7, 2005, explaining that, due to funding constraints in 
fiscal year 2005, we would not be able to address the petition in a 
timely manner. On February 28, 2006, the petitioner filed a 60-day 
notice of intent to sue the Department of the Interior for failure to 
issue 90-day and 12-month findings, and a proposed listing rule, as 
appropriate, in response to the petition as required by 16 U.S.C. 
1533(b)(3)(A) and (B). In response to the notice of intent to sue, we 
announced our intention to submit a 90-day finding to the Federal 
Register as expeditiously as possible.
    On July 29, 2008, we published in the Federal Register (73 FR 
43905) our 90-day finding that the petition presented substantial 
scientific information indicating that listing the Tucson shovel-nosed 
snake may be warranted. On March 31, 2010 (75 FR 16050), we published a 
12-month finding on the December 15, 2004, petition to list the Tucson 
shovel-nosed snake as an endangered or threatened species. In the 12-
month finding, we found that listing the Tucson shovel-nosed snake as 
an endangered or threatened species was warranted but precluded by 
higher priority actions. Upon publication of the 12-month finding, we 
added the Tucson shovel-nosed snake to the candidate list. Candidate 
species are those fish, wildlife, and plants for which we have on file 
sufficient information on biological status and threats to propose them 
for listing, but for which development of a proposed listing regulation 
is precluded by other higher priority listing activities. The Tucson 
shovel-nosed snake remained a candidate through all of our subsequent 
annual candidate notices of review (75 FR 69222, November 10, 2010; 76 
FR 66370, October 26, 2011; 77 FR 69994, November 21, 2012; and 78 FR 
70104, November 22, 2013).
    On September 9, 2011, the Service entered into a settlement 
agreement regarding species on the candidate list in multi-district 
litigation (Endangered Species Act Section 4 Deadline Litigation, No. 
10-377 (EGS), MDL Docket No. 2165 (D.D.C. May 10, 2011)), which we 
refer to as the ``MDL settlement agreement. '' Per the MDL settlement 
agreement, the Service is required to submit a proposed rule or a not 
warranted 12-month finding to the Federal Register for the Tucson 
shovel-nosed snake in Fiscal Year 2014, which ends September 30, 2014. 
This 12-month finding fulfills that requirement of the MDL settlement 
agreement.

Status Assessment for the Tucson Shovel-Nosed Snake

Introduction

    We completed a Species Status Assessment Report for the Tucson 
Shovel-Nosed Snake (SSA Report; Service 2014, entire), which is 
available online at https://www.regulations.gov under Docket Number FWS-
R2-ES-2014-0035). The SSA Report provides a thorough assessment of 
Tucson shovel-nosed snake's biology and natural history, and assesses 
demographic risks, threats, and limiting factors in the context of 
determining viability and risk of extinction for the subspecies. In the 
SSA Report, we compile biological data and a description of past, 
present, and likely future threats (causes and effects) facing the 
Tucson shovel-nosed snake. Because data in these areas of science are 
limited, some uncertainties are associated with this assessment. Where 
we have substantial uncertainty, we have attempted to make our 
necessary assumptions explicit in the SSA Report. We base our 
assumptions in these areas on the best available scientific and 
commercial data. Importantly, the SSA Report does not represent a 
decision by the Service on whether this subspecies warrants listing as 
an endangered or threatened species under the Act. The SSA Report does, 
however, provide the scientific basis that informs our regulatory 
decision (see Summary of Biological Status and Threats), which involves 
the application of standards within the Act and its implementing 
regulations and Service policies (see Finding).

Summary of Biological Status and Threats

    The SSA Report documents the results of the comprehensive 
biological status review for the Tucson shovel-nosed snake and provides 
a thorough

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account of the subspecies' overall viability and, conversely, 
extinction risk (Service 2014, entire). The SSA Report contains the 
data on which this finding is based. The following is a summary of the 
results and conclusions from the SSA Report.
    The Tucson shovel-nosed snake is a small, non-venomous snake (250-
425 millimeters (mm) (9.84-16.73 inches (in)) total length) in the 
family Colubridae, with a shovel-shaped snout, an inset lower jaw, and 
coloring that mimics coral snakes (Micrurus spp.) (Mahrdt et al. 2001, 
p. 731.1). The Tucson shovel-nosed snake is a subspecies of the western 
shovel-nosed snake (Chionactis occipitalis). The western shovel-nosed 
snake consists of four subspecies: Colorado Desert shovel-nosed snake 
(C. o. annulata), Mohave shovel-nosed snake (C. o. occipitalis), Nevada 
shovel-nosed snake (C. o. talpina), and Tucson shovel-nosed snake. The 
range of the western shovel-nosed snake extends from southern Nevada 
and southern California, across southwestern Arizona, and into Mexico. 
Snakes of the family Colubridae, which includes all shovel-nosed 
snakes, tend to be abundant in their respective habitats, widely 
distributed, and chiefly non-venomous; the family includes the 
kingsnakes, gartersnakes, and watersnakes. The Tucson shovel-nosed 
snake has been recognized as a subspecies of the western shovel-nosed 
snake since 1941. However, the original subspecies description was 
based on one color pattern variation compared to the other subspecies. 
More recent genetic studies, explained in detail below, have clarified 
that the identification of the subspecies based on color patterning is 
inaccurate and leads to under-representation of the actual extent of 
the subspecies' population. The geographical western extent of snakes 
with this distinguishing color pattern variation was never documented; 
therefore, the exact range of the subspecies was never described and 
was thought to be substantially smaller than our current understanding 
of the range as described below.
    At the time of the 2008 90-day and 2010 12-month findings, we 
accepted the taxonomic status and distribution of the subspecies as 
described by Mahrdt et al. (2001, entire). The range supported by 
Mahrdt et al. (2001, entire) encompassed approximately 1,149,367 
hectares (ha) (2,840,147 acres (ac)) and extended from Phoenix, 
Arizona, to Tucson, Arizona. A large intergrade zone was thought to 
exist where the Tucson shovel-nosed snake's and Colorado Desert shovel-
nosed snake's ranges overlapped; an intergrade zone is defined as an 
area of overlap between the ranges of two subspecies where individuals 
may possess intermediate characters (attributes or features that 
distinguish a subspecies, such as coloration) or traits of both 
subspecies. Snakes within the intergrade zone between Tucson shovel-
nosed snake and Colorado Desert shovel-nosed snake possessed color 
patterns characteristic (or intermediate) of both subspecies. Following 
our 90-day finding (July 29, 2008; 73 FR 43905), genetic studies 
involving mitochondrial DNA were conducted to help inform the taxonomy 
and genetic structure of the Tucson shovel-nosed snake and the 
intergrade zone. The data from this genetic study initially suggested 
that the Tucson shovel-nosed snake was not a valid subspecies. 
Therefore, we requested peer review and input in September 2008 on the 
issue of taxonomic classification and distribution of the snake. Four 
out of six peer reviewers believed that, based on genetic work by Wood 
et al. (2008, entire), the subspecies did not warrant taxonomic 
recognition; however, the peer reviewers also recognized that more 
conclusive genetic studies, including microsatellite data, were needed.
    These genetic studies were not complete until after our 2010 12-
month finding. Our 2010 12-month finding for the Tucson shovel-nosed 
snake (March 31, 2010; 75 FR 16050) acknowledged the uncertainty of the 
taxonomy of the snake, but recognized the best available scientific 
information continued to recognize the Tucson shovel-nosed snake as a 
subspecies. In the 2010 12-month finding, we continued to recognize the 
Mahrdt et al. (2001) representation of the range (which was limited to 
1,149,367 ha (2,840,147 ac)) with a large intergrade zone with the 
Colorado Desert shovel-nosed snake subspecies) and description as the 
best available science at that time. The 2010 12-month finding 
concluded that listing of the Tucson shovel-nosed snake was warranted 
but precluded by higher priority listing actions.
    Since the publication of our 2010 12-month finding (March 31, 2010; 
75 FR 16050), additional genetic work has been conducted for the Tucson 
shovel-nosed snake. This new genetic work supports that the Tucson 
shovel-nosed snake is a valid subspecies and that the subspecies 
occupies a much larger range than previously believed. A U.S. 
Geological Survey study used both mitochondrial DNA and 11 
microsatellite loci to assess whether patterns of population genetic 
structure follow the spatial structuring of phenotypic variation 
(variation in observable characteristics such as shape, color pattern, 
or even behavior) that originally led to the subspecies description and 
included samples from all subspecies of the western shovel-nosed snake 
throughout its range. The results and data from this study were made 
available to us prior to development of this SSA Report.
    We now understand that the western boundary of the estimated range 
of the Tucson shovel-nosed snake is almost 322 kilometers (km) (200 
miles (mi)) west of the range described by Mahrdt et al. (2001) and 
used by the Service to represent the range of the snake in our 2010 12-
month finding (see Figure 3 of the SSA Report). The estimated range 
supported in the U.S. Geological Survey study includes approximately 
2,000,655 ha (4,943,728 ac) more than the range we identified in our 
2010 12-month finding; this represents a 274 percent increase in our 
understanding of the estimated range of the subspecies. We recognize 
that there is considerable color pattern variation throughout the range 
of the Tucson shovel-nosed snake; however, the genetic data indicate 
that, despite the color pattern expressed, snakes previously thought to 
be a different subspecies within this range are genetically Tucson 
shovel-nosed snakes. Based on this new information, the current 
estimated range of the snake encompasses 3,150,022 ha (7,783,875 ac) of 
land.
    The current estimated range of the Tucson shovel-nosed snake 
includes Pinal, Maricopa, Yavapai, Yuma, Pima, and La Paz Counties in 
central and western Arizona. Although little is known about the 
specific habitat requirements of the Tucson shovel-nosed snake within 
its current estimated range, the subspecies is generally found within 
the Arizona Upland and Lower Colorado River Valley subdivisions 
(regions with diverse and distinctive vegetation) of the Sonoran 
Desertscrub biotic community, in areas containing: (1) Soils comprised 
of soft, sandy loams, with sparse gravel; and (2) sufficient prey items 
(insects and other arthropods). Of the total estimated range, 1,835,591 
ha (4,535,845 ac) (approximately 58 percent) contain the appropriate 
Sonoran Desertscrub habitat for the snake (see Figure 1 of the SSA 
Report).
    In conducting our status assessment, we first considered what the 
Tucson shovel-nosed snake needs to ensure viability. We generally 
define viability as the ability of the species to persist over the long 
term and, conversely, to avoid extinction. We then evaluated whether or 
not the vital resources needed for the snake's persistence

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currently exist and the repercussions to the subspecies when those 
resources are missing, diminished, or inaccessible. We next consider 
the factors that may interfere with the snake's needs, including 
historical, current, and future factors. Finally, considering the 
information reviewed, we evaluated the current status and future 
viability of the subspecies in terms of resiliency, redundancy, and 
representation.
    Resiliency is having sufficiently large populations for the 
subspecies to withstand stochastic events; in the case of the Tucson 
shovel-nosed snake, resiliency is likely best measured by the extent of 
what the best available information describes as suitable habitat: 
intact Sonoran Desertscrub vegetation that contains soft, sandy loam 
soils, and supports abundant prey. Although we do not have specific 
metrics on population health or abundance for the Tucson shovel-nosed 
snake, we assume that distribution of suitable habitat is an 
appropriate surrogate to indicate resiliency for this subspecies 
because snakes are distributed throughout the entirety of their range 
and we assume that these snakes generally occupy areas where suitable 
habitat exists. Redundancy is having a sufficient number of populations 
for the subspecies to withstand catastrophic events within part of its 
range and can be measured through the duplication and distribution of 
resilient populations across its range. Representation is having the 
breadth of genetic makeup of the subspecies to adapt to changing 
environmental conditions and can be measured by the genetic diversity 
within and among populations, and the ecological diversity of 
populations across the subspecies' range. In the case of the Tucson 
shovel-nosed snake, we evaluated representation based on the extent of 
the current estimated geographical range and the variability of habitat 
characteristics within this range as indicators of genetic and 
ecological diversity.
    For the Tucson shovel-nosed snake to be considered viable, 
individual snakes need the specific vital resources for survival and 
completion of their life cycles. Although there is a general lack of 
information regarding what the necessary vital resources are for the 
Tucson shovel-nosed snake to complete its life cycle, one study 
indicated that this snake selected habitat that included scattered sand 
hummocks (low mounds or ridges), crowned with mesquite or other desert 
shrubs, which can provide refuges for shovel-nosed snakes. The Tucson 
shovel-nosed snake is also found in creosote-mesquite floodplain 
environments, as well as sandy dunes, desert washes and valleys, and 
bajadas, most frequently in sparsely vegetated, sandy to gravelly 
habitats, and is less abundant in rocky terrain. Specifically, snakes 
are found within the Arizona Upland and Lower Colorado River Valley 
subdivisions of the Sonoran Desertscrub biotic community, in areas 
containing: (1) Soils comprised of soft, sandy loams, with sparse 
gravel; and (2) sufficient prey items (insects and other arthropods).
    We assume that the presence of the appropriate habitat types (as 
described above) throughout the subspecies' range provides sufficient 
area and suitable habitat to support the subspecies. This is because 
the Tucson shovel-nosed snake appears to be a habitat generalist 
occurring within the relatively broad biotic community described above. 
From an ecological perspective, the term habitat generalist describes a 
species that can tolerate a relatively wide range of environmental 
conditions, whereas habitat specialists can only tolerate a relatively 
narrow range of environmental conditions. Tucson shovel-nosed snakes 
are often found in open areas with sparse vegetation, and there are no 
specific habitat requirements for the percent vegetative cover 
preferred by this species. Rather, the subspecies' general requirements 
include proper soil and vegetation types, which provide both cover from 
predators and habitat for prey items. Additionally, connectivity 
between populations is essential to maintain diversity and the ability 
to find mates. Because generalists can tolerate a wider range of 
environmental conditions, they can generally adapt to minor, localized 
environmental changes within their broader habitat. Thus, the Tucson 
shovel-nosed snake is likely most sensitive to habitat changes that 
entirely remove suitable habitat from the subspecies' range rather than 
changes that result only in habitat modification. For these reasons, we 
focused our analysis in the SSA Report on landscape-scale stressors 
that could result in habitat loss.
    Within the redefined range of the subspecies, we do not have 
systematic survey data for habitat or population abundance estimates, 
and there are no minimum viable population estimates for the Tucson 
shovel-nosed snake. Throughout the areas within the subspecies' range 
that have had systematic surveys, populations of snakes appear to be 
stable (available information indicates that the species status neither 
improved nor declined since the last reporting period; i.e., population 
numbers remained constant) and persisting according to the survey data 
and analyses (Rosen 2003, entire; Rosen 2004; all and 2008b, entire; 
Arizona Game and Fish Department 2008, p. 2; Mixan and Lowery 2008, 
entire; Grandmaison and Abbate 2011, entire; Jones et al. 2011, p. 65; 
Grandmaison et al. 2012, entire; Leavitt et al. 2013a, entire). While 
we do not have specific data for densities of Tucson shovel-nosed 
snakes throughout their range, collection data indicate that the 
subspecies is found throughout the entirety of its estimated range (see 
Figure 6 in the SSA Report). We expect areas of unsurveyed, suitable 
habitat to support similar populations to those areas that have been 
systematically surveyed because density of a species tends to be 
greatest near the center of its range and gradually declines toward the 
boundaries (Brown 1984, p. 258) and collection data generally tends to 
be biased towards areas that are more easily accessed by surveyors, 
such as along paved roads. In this case, based on the proximity of 
snakes collected to adjacent areas of unsurveyed, suitable snake 
habitat, including more inaccessible areas of suitable habitat, we 
assume that the Tucson shovel-nosed snake occupies these unsurveyed 
areas where suitable habitat exists. This conclusion is consistent with 
population data for Tucson shovel-nosed snakes in similar habitats 
throughout its range. Each collection location in Figure 6 of the SSA 
Report represents multiple individuals collected at each site. For 
example, although there are three locality points in La Paz County in 
the western portion of the range, we have data in our files for 11 
Tucson shovel-nosed snakes collected at those three points. Many times, 
specimens are collected in close proximity to each other and are 
represented by a single point on the map. Therefore, while Figure 6 of 
the SSA Report represents what we know regarding the distribution of 
the Tucson shovel-nosed snake, it underestimates the actual number of 
snakes collected or sampled at these locations. Overall, we expect that 
the subspecies' populations throughout the snake's range currently have 
fairly similar population abundances to the areas that have been 
surveyed (please refer to Chapter 4 ``Species Current Conditions'' of 
the SSA Report).
    Potential threats to the viability of the Tucson shovel-nosed snake 
occur in the form of urban development, solar facilities, and roads 
associated with both urban development and solar facilities. These 
various factors result in habitat loss, thereby contributing to the

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potential decline or extirpation of local populations of Tucson shovel-
nosed snakes. Because the snake is a habitat generalist (as described 
above), we assume that the presence of the appropriate habitat types 
will contribute to the viability of the subspecies and that the removal 
of these habitat types due to development will decrease the subspecies' 
viability. Thus, the potential threats we analyzed in the SSA Report 
focus on the factors that may result in habitat loss. We evaluated 
these factors in the near term (over about the next 10 years) and into 
the future (over the next 11 to 50 years). Based on our analysis of the 
subspecies and the factors affecting it in the future, we believe that 
50 years is the longest length of time that we can reliably predict the 
future habitat conditions of the subspecies' range. This is because the 
potential threats to the subspecies focus on loss of suitable habitat, 
and our projections of management of lands upon which the subspecies 
relies is limited to approximately 50 years.
    Based on the best scientific and commercial data available, the 
Tucson shovel-nosed snake occupies a range of 3,150,022 ha (7,783,875 
ac), with 1,835,591 ha (4,535,845 ac) of the current estimated range 
being suitable habitat, and habitat development will impact only a 
small percentage of that range. Currently, 608,433 ha (1,503,472 ac) of 
land within the estimated range of the Tucson shovel-nosed snake falls 
within 31 municipal boundaries; the majority of the areas within these 
municipal boundaries have either already been developed or are planned 
for some level of development. Large areas of existing urban 
development and planned development that overlap with the subspecies' 
habitat primarily occur in the eastern and north-central portion of its 
range along the Interstate 10 corridor between Tucson and Phoenix; 
however, we do not have information to indicate when the planned 
communities will be developed or how much Tucson shovel-nosed snake 
habitat would be lost as a result. Thus, our analysis includes the 
total area of all municipalities, and we assume that all areas would be 
developed within each municipality. We did not differentiate between 
existing and potential future development; rather, we assumed all 
currently or reasonably potentially developed municipal lands would be 
lost to the subspecies. These areas of existing or potential future 
development represent approximately 19 percent of the 3,150,022 ha 
(7,783,875 ac) of the current estimated range of the Tucson shovel-
nosed snake. These area of existing or potential future development are 
33 percent of the 1,835,591 ha (4,535,845 ac) of Tucson shovel-nosed 
snake suitable habitat. We anticipate, but did not quantify or rely on, 
that the area that would be developed would be less than the total area 
described above, resulting in a reduced contribution to potential 
habitat loss than the maximum projected if all of this development 
occurs.
    Lands managed by the Arizona State Land Department (ASLD) 
containing habitat for the Tucson shovel-nosed snake are prevalent 
throughout much of its range (see Figure 2 of the SSA Report), and 
these ASLD lands have the potential to be sold for development, 
especially to facilitate growth around Phoenix and in western Pinal 
County. For example, Superstition Vistas, a large master planned 
community of approximately 275 square miles (712 square kilometers) 
located between Florence and Apache Junction, has been conceptually 
planned by the ASLD, and this plan has been incorporated into Pinal 
County's Comprehensive Plan (https://www.superstition-vistas.org). These 
ASLD lands where development may occur are included in the percentage 
of lands subject to existing or potential future development within the 
Tucson shovel-nosed snake's range. However, many of these ASLD lands, 
especially in the western portion of the subspecies' range, are so 
remote that we do not reasonably anticipate them being developed in the 
foreseeable future. Regardless, we included the potential development 
of these lands in our analysis of existing and potential future 
development. Other areas like Superstition Vistas are highly likely to 
be developed in the coming years. In most cases, community master plans 
indicate that these developments may incorporate open space areas 
containing habitat for the snake. These open space areas are 
anticipated to maintain some degree of suitable habitat for the Tucson 
shovel-nosed snake, although we do not know to what extent these areas 
would contribute to the snake's viability. Overall, at least in the 
near future, these ASLD lands are expected to continue to contribute to 
the resiliency, redundancy, and representation of the snake throughout 
its range. However, in the long term, some of these ASLD lands may be 
developed and contribute to habitat loss, and were considered in the 
SSA Report as potential lost habitat to the subspecies.
    Similar to urban development, solar energy development and 
associated transmission corridors may contribute to habitat loss 
affecting the Tucson shovel-nosed snake. All of these activities may 
impact the subspecies through removal and potential contamination of 
remaining habitat and increased potential for road kill. Currently, 
there is one approved solar facility and two applications for new solar 
facilities that have been received by the Bureau of Land Management 
(BLM) within the range of the snake. The approved facility does not 
have a power purchase agreement; therefore, we are uncertain if or when 
it will actually be constructed. We also are uncertain whether the 
facilities associated with the two applications will be approved or 
built. If all three of the solar facilities are constructed, the 
resulting habitat lost would include approximately 7,070 ha (17,472 
ac). This comprises less than one percent of the land within suitable 
habitat of the current estimated range of the snake. If all three of 
these facilities are constructed, there would likely be some level of 
diminished resiliency associated with local populations of snakes. 
However, the overall redundancy and representation of populations is 
expected to remain at current levels due to the size of the subspecies' 
range and the fact that these solar facilities are anticipated to be 
limited in occurrence, only removing a small fraction of available 
habitat compared to the total habitat available to snakes throughout 
their range.
    Roadways and transportation corridors raise similar concerns for 
the Tucson shovel-nosed snake. In most instances, new roads would be 
associated with urban development or solar facilities. Roadways may 
remove suitable habitat for the snake and could result in fatality of 
individuals. However, data in our files indicate that populations of 
Tucson shovel-nosed snakes are currently persisting along roads in 
areas of high traffic use. Although roads have been documented to be 
detrimental to snakes, particularly individuals, long-term studies show 
that they do not have as significant an effect on the resiliency or 
redundancy of populations as previously believed. Off-highway vehicle 
(OHV) use could also have similar affects to Tucson shovel-nosed snakes 
through habitat degradation when these vehicles create new trails. 
However, OHV use is most likely to occur on ASLD or private lands near 
larger urban developments, because OHV use is restricted on public 
lands throughout the subspecies' range. Thus, the limited use of OHVs 
on most BLM lands, which encompasses a large portion of lands with the 
subspecies' current estimated range, is not expected

[[Page 56735]]

to reduce resiliency and redundancy of the subspecies throughout its 
range.
    Although there are some potential impacts to the Tucson shovel-
nosed snake resulting from urban development, solar development, and 
roads associated with both forms of development, the estimated range of 
the Tucson shovel-nosed snake includes large tracts of lands managed by 
the BLM that contain suitable habitat for the snake. Collectively, 
these specially managed areas include approximately 770,163 ha 
(1,903,115 ac), which represents approximately 42 percent of the 
1,835,591 ha (4,535,845 ac) of the suitable habitat within the current 
estimated range of the Tucson shovel-nosed snake. These lands include 
wilderness areas, Areas of Critical Environmental Concern (ACECs), 
national monuments, and a wilderness study area. In addition to these 
designated areas, there are several other tracts of BLM land that are 
managed for wilderness characters and wildlife habitat within the range 
of the subspecies. Although none of these lands are specifically 
managed for the benefit of the Tucson shovel-nosed snake, they are 
managed to maintain their natural state. As discussed previously, the 
subspecies is a habitat generalist, and we assume that general habitat 
management of these specially managed BLM lands will contribute to 
maintenance of suitable habitat for the subspecies. Further, we expect 
that these specially managed lands will be protected from potential 
impacts in the foreseeable future and, thus, are likely to continue to 
provide suitable habitat for the Tucson shovel-nosed snake into the 
future. BLM lands outside of these special management areas are still 
subject to multiple-use management, primarily livestock grazing and 
recreational use, including OHV use. However, we have no evidence that 
the effects of livestock grazing are a threat to Tucson shovel-nosed 
snakes, and OHV use is restricted to existing routes under all BLM Land 
and Resource Management Plans. Therefore, BLM lands that allow for 
livestock grazing and limited OHV use will continue to provide suitable 
habitat for the Tucson shovel-nosed snake.
    Although most of the BLM land within the subspecies' range occurs 
in the eastern portion of the Tucson shovel-nosed snake's range, the 
western portion of the snake's range also includes large tracts of land 
managed by the ASLD. This land can be sold at any time for the benefit 
of the State Trust Land beneficiaries, but these lands in the western 
portion of the snake's range are remote, and many are currently used 
for livestock grazing. Therefore, we do not expect them to be sold in 
the foreseeable future and anticipate that they will remain as suitable 
habitat for the Tucson shovel-nosed snake. ASLD lands in the eastern 
portion of the range of the snake have high potential for development; 
however, as discussed above, they represent only a limited portion of 
the suitable habitat available throughout the range of the snake. 
Because these ASLD lands currently appear to support suitable Sonoran 
Desertscrub habitat for the Tucson shovel-nosed snakes and the 
subspecies is a habitat generalist, we assume that large tracts of 
specially managed BLM land and remote ASLD land provide habitat for the 
snake. In addition, we have location data that indicate the snake is 
relatively evenly distributed throughout its range, including on these 
protected lands (see ``Abundance'' section of the SSA Report).
    In summary, we evaluated a variety of different factors that could 
contribute to habitat loss for the subspecies. Urban development has 
the highest potential to occur within the subspecies' range and is 
likely to cause some level of habitat loss affecting the Tucson shovel-
nosed snake. Urban development is most likely to occur in the eastern 
and north-central portion of the snake's range along the Interstate 10 
corridor between Phoenix and Tucson and other outlying areas. If this 
predicted urban development occurs at the high-end estimates we discuss 
in the SSA Report, the total habitat lost is estimated to be 
approximately 33 percent of the Tucson shovel-nosed snake's suitable 
habitat. Conversely, protected lands will likely continue to provide 
suitable habitat for the Tucson shovel-nosed snake. Large areas of BLM 
land, including vast areas of specially managed lands, containing 
suitable habitat occur throughout the range of the subspecies. These 
specially managed BLM lands include approximately 42 percent of the 
suitable habitat throughout the snake's current estimated range. All of 
these public lands containing habitat for the Tucson shovel-nosed snake 
are expected to be managed as such in perpetuity, ensuring continued 
resiliency, redundancy, and representation of snake populations 
throughout its range. Overall, we expect some level of habitat loss to 
result from urban development, solar energy development, and roads 
associated with both forms of development. However, these impacts do 
not currently have, nor are they likely to have in the future, a 
significant species-level effect because much of the development has 
already occurred, and the spatial and temporal effect of development 
into the foreseeable future will be limited and is offset by the 
presence of protected lands. Our new understanding of the size of the 
subspecies' range, the snake's known distribution throughout its range, 
and the lack of pervasive threats throughout its range indicate the 
existence of the necessary resources for the subspecies' persistence 
now and in the long term, even if development occurs as described 
above. In conclusion, due to the distribution and extent of suitable 
habitat within the subspecies' current estimated range, the subspecies 
exhibits resiliency, redundancy, and representation such that it does 
not meet the definition of an endangered or a threatened species under 
the Act.

Finding

Standard for Review

    Section 4 of the Act, and its implementing regulations at 50 CFR 
part 424, set forth the procedures for adding species to the Federal 
Lists of Endangered and Threatened Wildlife and Plants. Under section 
4(b)(1)(a) of the Act, the Secretary is to make endangered or 
threatened species determinations required by the section 4(a)(1) 
solely on the basis of the best scientific and commercial data 
available to her after conducting a review of the status of the species 
and after taking into account conservation efforts by States or foreign 
nations. The standards for determining whether a species is an 
endangered or threatened species are provided in section 3 of the Act. 
An endangered species is any species that is ``in danger of extinction 
throughout all or a significant portion of its range.'' A threatened 
species is any species that is ``likely to become an endangered species 
within the foreseeable future throughout all or a significant portion 
of its range.'' Per section 4(a)(1) of the Act, in reviewing the status 
of the species to determine if it meets the definition of ``an 
endangered species'' or of a ``threatened species,'' we determine 
whether any species is an endangered or threatened species because of 
any of the following five factors: (A) The present or threatened 
destruction, modification, or curtailment of its habitat or range; (B) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) the inadequacy of 
existing regulatory mechanisms; and (E) other natural or manmade 
factors affecting its continued existence.
    Until recently, the Service has presented its evaluation of 
information under the five listing factors in an

[[Page 56736]]

outline format, discussing all of the information relevant to any given 
factor and providing a factor-specific conclusion before moving to the 
next factor. However, the Act does not require findings under each of 
the factors, only an overall determination as to status (e.g., 
endangered species, threatened species, not warranted). Ongoing efforts 
to improve the efficiency and efficacy of the Service's implementation 
of the Act have led us to present this information in a different 
format that we believe leads to greater clarity in our understanding of 
the science, its uncertainties, and the application of our statutory 
framework to that science. Therefore, while the presentation of 
information in this rule differs from past practice, it differs in 
format only. We have evaluated the same body of information we would 
have evaluated under the five listing factors outline format, we are 
applying the same information standard, and we are applying the same 
statutory framework in reaching our conclusions.

Endangered or Threatened Species Throughout Its Range

    Subsequent to our 2010 12-month finding, substantial new 
information has become available related to the genetics, range, and 
distribution of the Tucson shovel-nosed snake. On the basis of our 
biological review documented in the SSA Report, we have found merit in 
the recent genetic work presented in Wood et al. (2014, entire) and 
have revised our understanding of the range of the Tucson shovel-nosed 
snake based on this genetic information. As a result, the range of the 
Tucson shovel-nosed snake is considerably larger than the range we 
considered in our 2010 12-month finding. Therefore, in the associated 
SSA Report, we evaluated the various past, current, and future 
stressors known to negatively affect the Tucson shovel-nosed snake, but 
we expanded our analysis to include the entirety of the redefined range 
of the subspecies.
    The primary past, current, and ongoing stressor to the Tucson 
shovel-nosed snake is habitat loss resulting from existing and 
potential future urban development. Secondary sources of habitat loss 
likely to affect the subspecies on a smaller-scale include solar energy 
development, road construction and maintenance, conversion of lands to 
agricultural use, wildfires, climate change, and drought. All of these 
stressors related to habitat loss are likely the most significant to 
the subspecies because they have the potential to remove Sonoran 
Desertscrub habitat that is necessary for individuals to complete their 
life history and for populations to maintain resiliency supported by 
sufficient intact tracts of habitat. Our analysis acknowledges that 
stressors resulting in habitat loss, including urban development, will 
continue to occur in portions of the Tucson shovel-nosed snake's range; 
however, we evaluated the scope and effect of these stressors 
throughout the subspecies' redefined range, and conclude that these 
stressors are limited to a small portion of the subspecies' range. 
Furthermore, a meaningful portion of the range of the Tucson shovel-
nosed snake is, and will be, protected for the foreseeable future under 
existing specific management by the BLM that is focused on maintaining 
intact Sonoran Desertscrub habitat. As a result, we expect stressors 
resulting in habitat loss may diminish the resiliency of local snake 
populations in portions of the subspecies' range but will not reduce 
the subspecies' resiliency, redundancy, and representation throughout 
its range. We conclude that adequate suitable habitat for the Tucson 
shovel-nosed snake will be available for the foreseeable future.
    Other potential stressors that we evaluated include overutilization 
for commercial and scientific purposes, disease, and predation. 
Unregulated take of Tucson shovel-nosed snakes is likely infrequent 
because specimens can be difficult to locate in the wild and are 
similar in appearance to venomous coral snakes, causing humans to be 
less likely to capture them. Disease has not been documented in Tucson 
shovel-nosed snakes, and, while predation by a variety of carnivores is 
known to occur, there is no information suggesting that predation 
occurs at higher levels than expected in a normally functioning 
ecosystem. Thus, these stressors are not reducing the subspecies' 
resiliency, redundancy, or representation and, therefore, are not 
reducing its viability.
    Tucson shovel-nosed snakes are found throughout the entirety of 
their redefined range, and it does not appear that the various 
stressors described above are occurring at such a magnitude that they 
are diminishing the subspecies' resiliency, redundancy, and 
representation throughout its range. Furthermore, the genetic work by 
Wood et al. (2014, entire) indicate that there is substantial genetic 
variability within the Tucson shovel-nosed snake, and that there 
appears to be ongoing exchange of genetic material within Tucson 
shovel-nosed snake populations, as well as among the subspecies of the 
western shovel-nosed snake. We are not aware of any other potential 
stressors or threats that may impact the subspecies or its habitat 
individually or in combination, as further discussed in the SSA Report. 
Because the Tucson shovel-nosed snake is a habitat generalist and due 
to the distribution and extent of suitable habitat within the Tucson 
shovel-nosed snake's estimated range, the subspecies exhibits 
resiliency, redundancy, and representation such that it does not meet 
the definition of an endangered or threatened species. Therefore, we 
find that listing the Tucson shovel-nosed snake as an endangered or a 
threatened species throughout its range is not warranted.

Distinct Vertebrate Population Segment

    Because we find that the Tucson shovel-nosed snake does not warrant 
listing as endangered or threatened throughout its range, we next 
consider whether there is an alternative characterization of the 
subspecies that may warrant listing under the Act as defined by policy 
or regulation. The Act provides for the consideration of listing of 
distinct vertebrate population segments (DPSs) as defined within 
section 3 of the Act. Under the Service's Policy Regarding the 
Recognition of Distinct Vertebrate Population Segments under the 
Endangered Species Act (DPS Policy; 61 FR 4722, February 7, 1996), 
three elements are considered in the decision concerning the 
establishment and classification of a possible DPS. These are applied 
similarly for addition to or removal from the Federal List of 
Endangered and Threatened Wildlife. These elements include:
    (1) The discreteness of a population in relation to the remainder 
of the species to which it belongs;
    (2) The significance of the population segment to the species to 
which it belongs; and
    (3) The population segment's conservation status in relation to the 
Act's standards for listing, delisting, or reclassification (i.e., is 
the population segment endangered or threatened).
Discreteness
    Under the DPS Policy, a population segment of a vertebrate taxon 
may be considered discrete if it satisfies either one of these 
conditions:
    (1) It is markedly separated from other populations of the same 
taxon as a consequence of physical, physiological, ecological, or 
behavioral factors. Quantitative measures of genetic or morphological 
discontinuity may provide evidence of this separation.
    (2) It is delimited by international governmental boundaries within 
which differences in control of exploitation, management of habitat, 
conservation status, or regulatory mechanisms exist

[[Page 56737]]

that are significant in light of section 4(a)(1)(D) of the Act.
    With regard to the Tucson shovel-nosed snake, our evaluation of the 
status of this subspecies, as outlined in the SSA Report, indicates 
that the snake does not meet the criteria for discreteness required by 
our DPS policy. The best available scientific information indicates 
that there are no physical, physiological, ecological, or behavioral 
factors within the range of the Tucson shovel-nosed snake that point to 
any segment of the population being discrete. Genetic work shows 
genetic diversity and evidence of genetic exchange across the range of 
the snake, indicating that populations within the range are interacting 
and are not discrete (Wood et al. 2008, entire; Wood et al. 2014, 
entire). Furthermore, the Tucson shovel-nosed snake is not delimited by 
international governmental boundaries within which differences in 
control of exploitation, management of habitat, conservation status, or 
regulatory mechanisms exist that are significant in light of section 
4(a)(1)(D) of the Act. Because there are no discrete population 
segments within the Tucson shovel-nosed snake, it is unnecessary for us 
to complete any further analysis under the DPS policy.

Significant Portion of the Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is an endangered or a threatened species 
throughout all or a significant portion of its range. The Act defines 
``endangered species'' as any species which is ``in danger of 
extinction throughout all or a significant portion of its range,'' and 
``threatened species'' as any species which is ``likely to become an 
endangered species within the foreseeable future throughout all or a 
significant portion of its range.'' The term ``species'' includes ``any 
subspecies of fish or wildlife or plants, and any distinct population 
segment [DPS] of any species of vertebrate fish or wildlife which 
interbreeds when mature.'' We published a final policy interpreting the 
phrase ``significant portion of its range'' (SPR) (79 FR 37578, July 1, 
2014). The final policy states that (1) if a species is found to be an 
endangered or a threatened species throughout a significant portion of 
its range, the entire species is listed as an endangered or a 
threatened species, respectively, and the Act's protections apply to 
all individuals of the species wherever found; (2) a portion of the 
range of a species is ``significant'' if the species is not currently 
an endangered or a threatened species throughout all of its range, but 
the portion's contribution to the viability of the species is so 
important that, without the members in that portion, the species would 
be in danger of extinction, or likely to become so in the foreseeable 
future, throughout all of its range; (3) the range of a species is 
considered to be the general geographical area within which that 
species can be found at the time the Service or the National Marine 
Fisheries Service makes any particular status determination; and (4) if 
a vertebrate species is an endangered or a threatened species 
throughout an SPR, and the population in that significant portion is a 
valid DPS, we will list the DPS rather than the entire taxonomic 
species or subspecies.
    The SPR policy is applied to all status determinations, including 
analyses for the purposes of making listing, delisting, and 
reclassification determinations. The procedure for analyzing whether 
any portion is an SPR is similar, regardless of the type of status 
determination we are making. Where we have found that the species is 
neither an endangered nor a threatened species throughout all of its 
range, we next determine whether the species is an endangered or a 
threatened species throughout a significant portion of its range. If it 
is, we list the species as an endangered or a threatened species, 
respectively; if it is not, we conclude that listing the species is not 
warranted.
    When we conduct an SPR analysis, we first identify any portions of 
the species' range that warrant further consideration. The range of a 
species can theoretically be divided into portions in an infinite 
number of ways. However, there is no purpose to analyzing portions of 
the range that are not reasonably likely to be significant and either 
an endangered or a threatened species. To identify only those portions 
that warrant further consideration, we determine whether there is 
substantial information indicating that (1) the portions may be 
significant and (2) the species may be in danger of extinction in those 
portions or likely to become so within the foreseeable future. 
Answering these questions in the affirmative is not a determination 
that the species is an endangered or a threatened species throughout a 
significant portion of its range--rather, it is a step in determining 
whether a more detailed analysis of the issue is required. A key part 
of this analysis is whether the threats are geographically concentrated 
in some way. If the threats to the species are affecting it uniformly 
throughout its range, no portion is likely to warrant further 
consideration. Moreover, if any concentration of threats applies only 
to portions of the range that clearly do not meet the biologically 
based definition of ``significant'' (i.e., the loss of that portion 
clearly would not be expected to increase the vulnerability to 
extinction of the entire species), those portions will not warrant 
further consideration.
    If we identify any portions that may be both (1) significant and 
(2) endangered or threatened, we engage in a more detailed analysis to 
determine whether these standards are indeed met. The identification of 
an SPR does not create a presumption, prejudgment, or other 
determination as to whether the species in that identified SPR is an 
endangered or a threatened species. We must go through a separate 
analysis to determine whether the species is an endangered or a 
threatened species in the SPR. To determine whether a species is an 
endangered or a threatened species throughout an SPR, we will use the 
same standards and methodology that we use to determine if a species is 
an endangered or a threatened species throughout its range.
    Depending on the biology of the species, its range, and the threats 
it faces, it may be more efficient to address the ``significant'' 
question first, or the status question first. Thus, if we determine 
that a portion of the range is not ``significant,'' we do not need to 
determine whether the species is an endangered or a threatened species 
there; if we determine that the species is not an endangered or a 
threatened species in a portion of its range, we do not need to 
determine if that portion is ``significant.''
    We considered whether there are any significant portions of the 
range where the Tucson shovel-nosed snake is in danger of extinction or 
is likely to become endangered in the foreseeable future by reviewing 
the SSA Report with respect to the geographic concentration of threats, 
and the significance of portions of the range to the conservation of 
the subspecies. However, there were no portions of the subspecies' 
range that we considered biologically ``significant'' because the 
habitat conditions and distribution of the snake were generally similar 
across the entire subspecies' range and there is relatively high 
genetic diversity across the entire range. Therefore, we next chose to 
identify any portions of the Tucson shovel-nosed snake's range where 
the subspecies may be in danger of extinction or likely to become so 
within the foreseeable future. We concluded that the best available 
information indicates that the impacts identified in the SSA Report do 
not occur uniformly throughout the range of

[[Page 56738]]

the Tucson shovel-nosed snake. The most significant impact to the 
Tucson shovel-nosed snake is urban development and associated 
activities. The SSA Report describes that the majority of urban 
development has occurred and will likely continue to occur within the 
north-central and eastern portions of the Tucson shovel-nosed snake's 
range, primarily along the Interstate 10 corridor. Because urban 
development represents a permanent loss of Tucson shovel-nosed snake 
habitat, it is within these areas that the extent of the impact could 
be such that the Tucson shovel-nosed snake in this portion of the range 
may be in danger of extinction or is likely to become endangered in the 
foreseeable future. Having identified this portion of the range as 
potentially having endangered or threatened status, we must next 
determine if this portion of the range is significant. As described 
above, we would consider such a portion of the range significant if, 
should that portion of the range be theoretically extirpated, the 
species in the remaining portion of the range would be in danger of 
extinction now or in the foreseeable future (in other words, endangered 
or threatened). The best available information suggests that, should 
the Tucson shovel-nosed snake be extirpated from areas of urban 
development in the north-central and eastern portions of its range, the 
remainder of its range would retain adequate resiliency, redundancy, 
and representation. There are no significant stressors to the remainder 
of the range of the subspecies due, in large part, to the large areas 
of habitat that would remain protected into the foreseeable future. 
Therefore, we find that the Tucson shovel-nosed snake is not in danger 
of extinction now, or likely to become so in the foreseeable future, in 
a significant portion of its range.
    Based on the information presented in the SSA Report for the Tucson 
shovel-nosed snake, and on the discussion above, we find that the best 
available scientific and commercial information does not indicate that 
the threats to the Tucson shovel-nosed snake rise to the level of 
significance such that this subspecies is in danger of extinction now 
or likely to become so in the foreseeable future throughout all or a 
significant portion of its range. As a result, we have determined that 
this subspecies does not meet the definition of an endangered or 
threatened species under the Act and are subsequently removing this 
subspecies from our candidate list.

References Cited

    A complete list of references cited is available in the SSA Report 
(Service 2014, pp. 69-74), available on the Internet at https://www.regulations.gov at Docket Number FWS-R2-ES-2014-0035, and upon 
request from the Arizona Ecological Services Field Office (see 
ADDRESSES).

Authors

    The primary authors of this notice are the staff members of the 
Arizona Ecological Services Field Office.

Authority

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

    Dated: September 9, 2014.
Rowan W. Gould,
Acting Director, U. S. Fish and Wildlife Service.
[FR Doc. 2014-22331 Filed 9-22-14; 8:45 am]
BILLING CODE 4310-55-P