[Federal Register: May 15, 2008 (Volume 73, Number 95)]
[Proposed Rules]
[Page 28094-28097]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15my08-28]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[FWS-R2-ES-2008-0037; 92220-1113-0000-C5]
Endangered and Threatened Wildlife and Plants; 90-Day Finding on
Petition To Delist the Hualapai Mexican Vole (Microtus mexicanus
hualpaiensis)
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of 90-day petition finding.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), make a 90-
day finding on a petition to remove the Hualapai Mexican vole (Microtus
mexicanus hualpaiensis) from the Federal List of Threatened and
Endangered Wildlife and Plants pursuant to the Endangered Species Act
(Act). We find that the petition presents substantial information
indicating that delisting this mammal may be warranted. We are
initiating a status review to determine if delisting this subspecies is
warranted. We are requesting submission of any information on the
Hualapai Mexican vole relevant to its listing status under the Act.
Following this review, we will issue a 12-month finding on the
petition.
DATES: This finding was made on May 15, 2008. To be considered in the
12-month finding on this petition, comments and information should be
submitted to us by July 14, 2008.
ADDRESSES: You may submit written comments and materials to us by one
of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov.
Follow the instructions for submitting comments.
U.S. mail or hand-delivery: Public Comments Processing,
Attn: Docket FWS-R2-ES-2008-0037, Division of Policy and Directives
Management, U.S. Fish and Wildlife Service, 4401 N. Fairfax Drive,
Suite 222, Arlington, VA 22203.
We will not accept e-mail or faxes. We will post all comments on
http://www.regulations.gov. This generally means that we will post any
personal information you provide us (see the Public Comments Solicited
section below for more information).
You may obtain copies of the petition, reports, and reviews of
reports upon which this 90-day finding is based by visiting the Federal
eRulemaking Portal at http://www.regulations.gov or our Web site at
http://www.fws.gov/southwest/es/arizona/, or by contacting the Arizona
Ecological Services Field Office at the address or contact numbers
under ADDRESSES.
FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, U.S.
Fish and Wildlife Service, Arizona Ecological Services Field Office; by
telephone at 602/242-0210; or by facsimile at 602/242-2513. Persons who
use a telecommunications device for the deaf (TDD) may call the Federal
Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Act (16 U.S.C. 1531 et seq.) requires
that we make a finding on whether a petition to list, delist, or
reclassify a species presents substantial scientific or commercial
information indicating that the petitioned action may be warranted. We
are to base this finding on information provided in the petition. To
the maximum extent practicable, we must make this finding within 90
days of receipt of the petition, and publish the finding promptly in
the Federal Register.
Our review of a 90-day finding under section 4(b)(3)(A) of the Act
and 50 CFR 424.14(b) is limited to a determination of whether the
information in the petition meets the ``substantial information''
threshold. ``Substantial information'' is defined in section 424.14(b)
of our regulations as ``that amount of information that would lead a
reasonable person to believe that the measure proposed in the petition
may be warranted.'' Petitioners need not prove that the petitioned
action is warranted to support a ``substantial'' finding; instead, the
key consideration in evaluating a petition for substantiality involves
demonstration of the reliability and adequacy of the information
supporting the action advocated by the petition.
We have to satisfy the Act's requirement that we use the best
available science to make our decisions. However, we do not conduct
additional research at this point, nor do we subject the petition to
rigorous critical review. Rather, at the 90-day finding stage, we
accept the petitioner's sources and characterizations of the
information, to the extent that they appear to be based on accepted
scientific principles (such as citing published and peer reviewed
articles, or studies done in accordance with valid methodologies),
unless we have specific information to the contrary. Our finding
considers whether the petition states a reasonable case on its face
that delisting may be warranted. Thus, our 90-day finding expresses no
view as to the ultimate issue of whether the species should no longer
be classified as a threatened species. We make no determinations as to
the value, accuracy, completeness, or veracity of the petition. The
contents of this finding summarize that information that was available
to us at the time of the petition review.
In making this finding, we relied on information provided by the
petitioner and information available in our files at the time we
reviewed the petition, and we evaluated that information in accordance
with 50 CFR 424.14(b). Our process for making a 90-day finding under
section 4(b)(3)(A) of the Act and section 424.14(b) of our regulations
is limited to a determination of whether the information contained in
the petition meets the ``substantial information'' threshold.
On August 23, 2004, we received a petition dated August 18, 2004,
from the Arizona Game and Fish Department (AGFD 2004) to delist the
Hualapai Mexican vole (Microtus mexicanus hualpaiensis). The petition
(AGFD 2004, pp. 4-6) states that: (1) The subspecies occurs over a much
greater area and in higher numbers than previously thought; (2) it is
likely that all populations referred to as M. m. hualpaiensis, along
with other populations of the species in Arizona, should be referred to
as M. m. mogollonensis; and (3) the threats faced by this more
widespread taxon do not indicate that listing under the Act is
warranted.
Species Information
The Mexican vole is a cinnamon-brown, mouse-sized rodent
approximately 5.5 inches (14 cm) long with a short tail and small ears
that are obscured by its fur (Hoffmeister 1986, p. 441; 52 FR 36776,
October 1, 1987).
Goldman (1938, pp. 493-494) described and named the Hualapai
Mexican vole (also known as the Hualapai vole) as Microtus mexicanus
hualapaiensis in 1938. This was based on only four specimens, but
Cockrum (1960, p. 210), Hall (1981, p. 481), and Hoffmeister (1986, pp.
444-445) all recognized the subspecies. M. m.
[[Page 28095]]
hualpaiensis has been considered one of three subspecies of M.
mexicanus found in Arizona (Kime et al. 1995, p. 1). It was
distinguished from M. m. navaho to the northeast by a slightly longer
body, longer tail, and longer and broader skull (Hoffmeister 1986, p.
443). It was distinguished from M. m. mogollonensis by a longer body,
shorter tail, and a longer and narrower skull (Hoffmeister 1986, p.
443).
The final rule listing M. m. hualpaiensis (52 FR 36776) indicated
that this subspecies occupied the Hualapai Mountains, but also
acknowledged that Spicer et al. (1985, p. 10) noted similar voles from
the Music Mountains and that Hoffmeister (1986, p. 445) had tentatively
assigned specimens from Prospect Valley to M. m. hualpaiensis. The rule
stated that if future taxonomic evaluation of voles from the Music
Mountains and Prospect Valley should indicate that they are M. m.
hualpaiensis, the voles from the Music Mountains and Prospect Valley
would be covered by the listing of the subspecies.
At the time of Federal listing, little was known about the life
history of the Hualapai Mexican vole, but it was assumed to be similar
to the other two M. mexicanus subspecies (Service 1991, p. 1). Hualapai
Mexican voles are probably active year-round, as are other Microtus
species (Spicer et al. 1985, p. 22). It is assumed they have small
litters, similar to the other two subspecies, as they have only two
pairs of mammae (mammary glands), which limits the number of young that
can be nursed (Hoffmeister 1986, p. 443). Mexican voles are typically
found in xeric (dry) habitats, unlike most Microtus species, which are
associated with mesic (intermediate moisture) habitats (Tamarin 1985,
p. 99).
A recovery plan for the Hualapai Mexican vole was completed and
signed in August 1991. It outlined recovery objectives and has directed
management and research priorities for the ensuing years.
Recent Taxonomy
Following Federal listing of the Hualapai Mexican vole, several
focused surveys of the subspecies' distribution, habitat requirements,
and genetic relationship to other M. mexicanus subspecies were
undertaken. The petition reviews the taxonomic history of the Hualapai
Mexican vole and recent genetic studies that have a bearing on its
taxonomic status and concludes that only one subspecies of M. mexicanus
should be recognized in Arizona. We briefly describe the petition's
interpretations of these genetic studies below. Researchers did not
collect or analyze samples from the exact same locations, so site names
across studies do not necessarily match. We have presented site names
and resulting population assignments as described in the petition and
studies cited in the petition.
As a point of clarification, Frey and LaRue (1993, p. 176) asserted
that Mexican voles from Mexico are distinct from populations in the
United States based on genetic and morphologic data. They assigned
voles in Arizona, New Mexico, and Texas that were formerly named M.
mexicanus to M. mogollonensis (Frey and LaRue 1993, pp. 176-177).
Because the Service did not formally change the scientific name of the
Hualapai Mexican vole, we continue to use the name M. mexicanus in this
finding.
The petition states that in 1993, Frey and Yates conducted a
genetic analysis on tissue samples from 12 populations (AGFD 2004, p.
2); there was an additional population from Mexico (Frey and Yates
1995, p. 9) not mentioned in the petition. According to the petition
(AGFD 2004, pp. 2-3), the results showed that three populations
(Hualapai Mountains, Hualapai Indian Reservation, and Music Mountains)
were genetically distinct from other populations in Arizona and
indicated that all three populations might be placed in the subspecies
M. m. hualpaiensis. The petition noted that Frey and Yates (1993)
stipulated that additional analyses including larger sample sizes might
substantiate their findings. The petition states that Frey and Yates
(1995) continued their work on the three Arizona subspecies and found
that six of the populations sampled (Hualapai Mountains, Hualapai
Indian Reservation, Music Mountains, Aubrey Cliffs/Chino Wash, Santa
Maria Mountains, and Bradshaw Mountains) could be placed in the
subspecies M. m. hualpaiensis (AGFD 2004, p. 3). In fact, Frey and
Yates (1995, p. 9) treated the Aubrey Cliffs and Chino Wash populations
as two distinct populations, bringing the number of M. m. hualpaiensis
populations to seven. They also believed that two other populations
(Round Mountain and Sierra Prieta) could be placed in the subspecies M.
m. hualpaiensis, based on geographic proximity (AGFD 2004, p. 3).
Additional genetic analyses were conducted by Busch et al. (2001).
According to the petition (AGFD 2004, p. 3), they assessed the
evolutionary relatedness of 11 of the 16 populations that Frey and
Yates reported on in 1995. In addition, they analyzed samples taken
from specimens in two other areas (Watson Woods and Navajo Mountain).
The petition states that their results did not support separation of M.
mexicanus in Arizona into three distinct subspecies. Populations
assigned to M. m. navajo from Navajo Mountain, Mingus Mountain, San
Francisco Peaks, and the Grand Canyon South Rim, and populations
assigned to M. m. mogollonensis from the Mogollon Rim, Chuska
Mountains, and White Mountains were not differentiated from those from
the Hualapai Mountains, Hualapai Indian Reservation, Aubrey Cliffs,
Bradshaw Mountains, Watson Woods, and Sierra Prieta (AGFD 2004, p. 3;
Busch et al. 2001, p. 2). The petition states that the authors believed
the specimens from the White Mountains and Chuska Mountains could be
considered a different subspecies, or they may simply show some genetic
difference due to geographic separation (AGFD 2004, p. 3; Busch et al.
2001, p. 11-12). According to Busch et al. (2001, p. 12) and
acknowledged by the petitioner, there is only one subspecies of M.
mexicanus in Arizona.
The petition included reviews by five experts familiar with genetic
research who analyzed the Busch et al. (2001) report. According to the
petition (AGFD 2004, pp. 3-4), one reviewer believed the data collected
from Hualapai Mountains, Hualapai Indian Reservation, Aubrey Cliffs/
Chino Wash, Bradshaw Mountains/Watson Woods, and Sierra Prieta
represented five populations of M. m. hualpaiensis. Conversely, the
reviewer concluded that the data from three sites (Mingus Mountain, San
Francisco Peaks, and Grand Canyon South Rim) represented a different
subspecies (M. m. navaho). The reviewer also suggested that the
populations found in the Music Mountains and the Santa Maria Mountains
were likely M. m. hualpaiensis based on ``less well-supported
morphologic, genetic, and biogeographic data,'' for a total of seven
populations. This reviewer did not include a discussion of M. m.
mogollonensis and the validity of that subspecies. The petition states
that the other four reviewers concurred overall with the conclusions in
Busch et al. (2001) that all populations sampled could be assigned to
M. m. hualpaiensis (AGFD 2004, p. 4).
Additionally, AGFD sent Busch et al.'s 2001 report to two different
experts on mammalian taxonomy. The petition states that one of the
taxonomic reviewers agreed with the dissenting genetic review discussed
in the preceding paragraph that there are sufficient data to support
distinguishing
[[Page 28096]]
more than one subspecies (AGFD 2004, p. 4). The reviewer concurred with
the geneticist's population assignments of the subspecies. The petition
states that the other taxonomic reviewer concluded that there is no
basis to consider the three subspecies separate, that the reviewer
stated that data used by Hoffmeister (1986) were insufficient to
recognize three subspecies, and the genetic analyses (DNA and isozyme)
(Frey and Yates 1993; 1995; Busch et al. 2001) were subject to
methodological problems (AGFD 2004, p. 4). The reviewer asserted that
all three subspecies should be considered as one, M. m. mogollonensis.
In summary, the various analyses and reviews present multiple
interpretations of the taxonomy and distribution of voles in Arizona,
none of which match that of our original listing. Although we are
unable to ascertain the correct interpretation at this time, we believe
the petitioner has presented reliable and accurate information
indicating (1) That the Hualapai Mexican vole, as currently listed, may
not be a valid taxonomic entity; and (2) that if the Hualapai Mexican
vole is a valid taxon, it likely occurs throughout a greater range than
originally thought.
Status Assessment
Pursuant to section 4 of the Act, we may list or delist a species,
subspecies, or Distinct Population Segment of vertebrate taxa on the
basis of any of the following five factors: (A) Present or threatened
destruction, modification, or curtailment of habitat or range; (B)
overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) inadequacy of
existing regulatory mechanisms; or (E) other natural or manmade factors
affecting its continued existence. If it is determined that the
Hualapai Mexican vole is a valid taxon occurring throughout a larger
range, a new status review, based on a review of the five listing
factors, would be required in order to determine if the Hualapai
Mexican vole still meets the definition of threatened or endangered
under the Act. This 90-day finding is not a status assessment and does
not constitute a status review under the Act. Therefore, what follows
below is a preliminary review of the factors affecting this subspecies,
as presented by the petitioner. Please note that the petitioner
addressed the subspecies as though it occurs in a larger range than
what is currently recognized. Because we only monitor populations of
Hualapai Mexican vole that occur within the Hualapai Mountains, as
described in the listing rule, we have very limited information in our
files with which to draw conclusions regarding potential populations
outside the Hualapai Mountains.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
The final rule listing the subspecies considered the Hualapai
Mexican vole to be extremely rare, with one of the most limited
habitats of any North American mammal (52 FR 36776). The habitat was
considered in danger of further degradation by cattle grazing and
increased human recreational activities. The petition asserts that the
subspecies occurs over a much greater area and in higher numbers than
previously thought (AGFD 2004, pp. 2-6; see Recent Taxonomy discussion
above). Therefore, loss of limited habitat should no longer be
considered a threat to the subspecies. In addition, the petitioner
asserts that the Hualapai Mexican vole is found in more xeric habitats
than most Microtus species (AGFD 2004, p. 5); therefore, trampling of
spring areas by cattle will not negatively affect the subspecies as
intensely as it was thought when the subspecies was listed.
The Service only tracks the status of the Hualapai Mexican vole
populations within the Hualapai Mountains, where it was listed. There
is not enough information in our files to assess the reliability of
information in the petition; therefore, we assume it is reliable.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
While the Hualapai Mexican vole is not sought for commercial,
recreational, or educational purposes, persecuted as a pest, or
collected for the pet trade, the final rule listing the species
indicated that an intensive trapping effort could eliminate a
population (52 FR 36773). The petition notes that collecting of the
Hualapai Mexican vole has historically been done for genetic analyses
and comparison of morphological measurements and that, historically,
the number of individuals taken was small relative to the number
captured (AGFD 2004, p. 6). Genetic analyses may continue, but will be
monitored through scientific collection permits authorized by the
petitioner, AGFD. The petitioner does not believe that this factor
rises to the level of a threat.
Overutilization for commercial, recreational, scientific, or
education purposes was not presented as a threat in the final listing
rule, and we have not received any reports of overutilization of
Hualapai Mexican voles in the Hualapai Mountains since the listing of
the subspecies. We have no information in our files to indicate that
the petitioner's information is unreliable or inaccurate.
C. Disease or Predation
The final rule listing the Hualapai Mexican vole states that little
is known about disease or predation in Hualapai Mexican vole
populations (52 FR 36778). However, species of Microtus are usually a
fundamental part of the base of the food pyramid, and many potential
predators occur in the Hualapai Mountains. Additionally, domestic cats
may pose a threat from the expanding residential area near Hualapai
Mountain Park. The petitioner notes that predation is not known to be a
problem, especially if the range of the subspecies is not limited to
the Hualapai Mountains (AGFD 2004, p. 6). Additionally, the petitioner
notes that domestic cats have rarely been observed in Hualapai Mountain
Park and, therefore, believes the threat of predation on Hualapai
Mexican voles is overstated in the listing rule. However, the
petitioner provides no information to support these assertions.
Although domestic cats have been mentioned as a threat (Spicer
1985, p. 28), we have no information to suggest these cats represent a
significant predation threat to the Hualapai Mexican vole. Therefore,
we assume that the petitioner's information is reliable.
D. The Inadequacy of Existing Regulatory Mechanisms
The petition states that the removal of Federal protections
afforded by the Act will not negatively affect Hualapai Mexican vole
populations, since the species' range and habitat requirements are not
as restricted as previously thought (AGFD 2004, p. 6). The petition
also recognizes that Arizona Game and Fish Commission Order 14
prohibits hunting or trapping of Hualapai Mexican voles. Arizona
Revised Statute (i.e., State Law) allows for the Commission to issue
orders regarding the hunting and trapping of wildlife in Arizona. Also,
since the petitioner, AGFD, has authority over scientific collection
permits, it can approve or deny permits based on submitted research
proposals (AGFD 2004, pp. 6-7).
The Service only tracks the status of the Hualapai Mexican vole
populations within the Hualapai Mountains, where it is listed. We do
not have any information in our files to indicate that a lack of
regulatory mechanisms could be a problem. Therefore, we assume that the
petitioner's information is reliable.
[[Page 28097]]
E. Other Natural or Manmade Factors Affecting Its Continued Existence
The final rule listing the Hualapai Mexican vole notes that the
areas of habitat supporting the subspecies are small and isolated (52
FR 36778). This mammal is thus fragmented into small populations that
may be subject to inbreeding and reduced genetic variability. Drought,
which can reduce water flow, vegetation growth, and ground cover, is an
additional threat to these populations (52 FR 36778). The petition
asserts that because the Hualapai Mexican vole's range is not as
restricted as once thought, manmade factors should not negatively
influence the continued existence of the species (AGFD 2004, p. 7).
Additionally, the petitioner states that drought is not a serious
threat to Hualapai Mexican vole populations, because the normal and
regular occurrence of drought probably allowed this vole to adapt to
drier habitat conditions (AGFD 2004, p. 7). The petitioner also
suggested that prescribed fire might improve or expand the habitat of
the species (AGFD 2004, p. 7).
The Service only tracks the status of the Hualapai Mexican vole
populations within the Hualapai Mountains, where it is listed. The
apparent continued presence of the vole in those mountains (Kime et al.
1995, p. 6) suggests that drought may not be as great a threat as was
thought at the time of listing. We did not address prescribed fire as a
manmade factor in our listing rule. There is not enough information in
our files to draw conclusions regarding the effects of drought or
prescribed burns on additional populations; however, we have no
information to indicate that the petitioner's information is unreliable
or inaccurate. Therefore, we assumed the petitioner's information is
reliable.
Finding
We have reviewed the petition and the supporting documents, as well
as other information in our files. We find that the petition presents
substantial information indicating that delisting the Hualapai Mexican
vole may be warranted. The petitioner has provided information
suggesting the taxon may occur over a greater range of the State than
known at the time of listing, and may not even warrant taxonomic
standing as a subspecies. As discussed above, given the limited
information in our files regarding these issues, we assume that the
information presented in the petition is reliable. If reliable, that
information is adequate to demonstrate that delisting may be warranted.
While significant questions remain about the taxonomy of the species
and threats facing the additional populations of voles, we consider
these questions to be issues relevant to the listing determination that
warrant further investigation. Accordingly, we believe it is
appropriate to consider this information and any other new information
available about this species, and the threats it may face, in a status
review.
Public Information Solicited
When we make a finding that a petition presents substantial
information to indicate that delisting a species may be warranted, we
are required to promptly commence a review of the status of the
species. Based on results of the status review, we make a 12-month
finding as required by section 4(b)(3)(B) of the Act. To ensure that
the status review is complete and based on the best available
scientific information, we are soliciting information on M. mexicanus
in Arizona. This includes information regarding historical and current
distribution, taxonomic status, biology and ecology, ongoing
conservation measures for the species and its habitat, and threats to
the species and its habitat. This information is particularly needed
for any populations of the taxon that were not among the three
potential populations considered to be M. m. hualapaiensis in the 1987
final listing. We also request information regarding the adequacy of
existing regulatory mechanisms. We request any additional information,
comments, and suggestions from the public, other concerned governmental
agencies, Tribes, the scientific community, industry or environmental
entities, or any other interested parties concerning the status of M.
mexicanus in Arizona.
We are particularly interested in the views of scientists with
expertise in mammalian taxonomy and the use of genetic data when making
taxonomic determinations of species and subspecies. In particular, we
are interested in review and comment on whether the information such as
the original morphological evidence and new genetic reports support or
refute the taxonomic validity of M. m. hualapaiensis.
If you wish to comment, you may submit your comments and materials
concerning this finding. You may submit your comments and materials
concerning the taxonomic and listing status of M. m. hualapaiensis by
one of the methods listed in the ADDRESSES section. We will not accept
comments sent by e-mail or fax or to an address not listed in the
ADDRESSES section. We will not accept anonymous comments; your comments
must include your first and last name, city, State , country, and
postal (zip) code. Finally, we will not consider hand-delivered
comments that we do not receive, or mailed comments that are not
postmarked, by the date specified in the DATES section. Comments
submitted via http://www.regulations.gov must be submitted before
midnight (Eastern Standard Time) on the date specified in the DATES
section.
We will post your entire comment--including your personal
identifying information--on http://www.regulations.gov. If you provide
personal identifying information in addition to the required items
specified on the previous paragraph, such as your street address, phone
number, or e-mail address, you may request at the top of your document
that we withhold this information from public review. However, we
cannot guarantee that we will be able to do so.
Comments and materials we receive, as well as supporting
documentation we used in preparing this finding, will be available for
public inspection on http://www.regulations.gov, or 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 (602/242-0210).
References Cited
A complete list of all references cited in this finding is
available, upon request, from the U.S. Fish and Wildlife Service,
Arizona Ecological Services Field Office, 2321 W. Royal Palm Road,
Suite 103, Phoenix, AZ 85021 (602/242-0210).
Authority
The authority for this action is section 4 of the Endangered
Species Act of 1973 (16 U.S.C. 1531 et seq.).
Dated: May 2, 2008.
Kenneth Stansell,
Acting Director, Fish and Wildlife Service.
[FR Doc. E8-10906 Filed 5-14-08; 8:45 am]
BILLING CODE 4310-55-P