Endangered and Threatened Wildlife and Plants; Revised Proposed Rule To Amend the Listing for the Preble's Meadow Jumping Mouse (Zapus hudsonius preblei), 62992-63024 [07-5486]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 72, Number 215 (Wednesday, November 7, 2007)]
[Proposed Rules]
[Pages 62992-63024]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-5486]



[[Page 62991]]

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Part III





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



 Endangered and Threatened Wildlife and Plants; Revised Proposed Rule 
To Amend the Listing for the Preble's Meadow Jumping Mouse (Zapus 
hudsonius preblei) To Specify Over What Portion of Its Range the 
Subspecies Is Threatened; Proposed Rule

Federal Register / Vol. 72, No. 215 / Wednesday, November 7, 2007 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AV64


Endangered and Threatened Wildlife and Plants; Revised Proposed 
Rule To Amend the Listing for the Preble's Meadow Jumping Mouse (Zapus 
hudsonius preblei) To Specify Over What Portion of Its Range the 
Subspecies Is Threatened

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Revised proposed rule.

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SUMMARY: Under the authority of the Endangered Species Act of 1973, as 
amended (Act), we, the U.S. Fish and Wildlife Service (Service), revise 
our February 2, 2005 (70 FR 5404), proposed rule to remove the Preble's 
meadow jumping mouse (Zapus hudsonius preblei) (Preble's) from the List 
of Endangered and Threatened Wildlife. We now propose to amend the 
listing for the Preble's meadow jumping mouse to specify over what 
portion of its range the subspecies is threatened. The best scientific 
and commercial data available demonstrates that: The Preble's meadow 
jumping mouse is a valid subspecies and should not be delisted based 
upon taxonomic revision; the subspecies is not threatened throughout 
all of its range; and the portion of the current range of the 
subspecies located in Colorado represents a significant portion of the 
current range where the Preble's meadow jumping mouse is likely to 
become endangered within the foreseeable future, and the subspecies in 
that portion of its range should retain its threatened status. We seek 
comments from the public regarding this revised proposal. Comments 
previously submitted need not be resubmitted as they have already been 
incorporated into the public record and will be fully considered in the 
final determination.

DATES: Written Comments: We will consider comments on this revised 
proposed rule that we receive by the close of business on January 22, 
2008. Any comments we receive after the closing date may not be 
considered in our final decision on the proposal.
    Open House and Public Hearing: We will hold an open house and 
public hearing on this revised proposed rule in Colorado on December 
10, 2007 and in Wyoming on December 12, 2007. Each open house will run 
from 4 p.m. to 5 p.m., with brief presentations about this revised 
proposed rule given at 4 p.m., and each public hearing will run from 6 
p.m. to 8 p.m.

ADDRESSES: Written Comments: If you wish to comment on this revised 
proposed rule, you may submit your comments and materials by any one of 
several methods:
    (1) By mail to: Susan Linner, Field Supervisor, Colorado Field 
Office, Ecological Services, P.O. Box 25486, MS-65412, Denver Federal 
Center, Denver, CO 80225.
    (2) By hand-delivery to: Susan Linner, Colorado Field Office at 134 
Union Blvd., Suite 670, Lakewood, CO 80228.
    (3) By fax to: (303) 236-4005.
    (4) By electronic mail (e-mail) to: FW6--PMJM@fws.gov. Please see 
the Public Comments Solicited section below for other information about 
electronic filing.
    (5) By the Federal eRulemaking Portal at: https://
www.regulations.gov. Follow the instructions on that Web site for 
submitting comments.
    Open House and Public Hearing: We will hold an open house and 
public hearing at the Colorado Field Office, 134 Union Boulevard, Room 
100A--Eagle Conference Room, Lakewood, CO 80228 and at the First State 
Bank Conference Center, 1405 16th Street, Wheatland, WY 82201.

FOR FURTHER INFORMATION CONTACT: Susan Linner, Field Supervisor, U.S. 
Fish and Wildlife Service, Colorado Field Office at 134 Union Blvd., 
Suite 670, Lakewood, CO 80228; telephone (303) 236-4773; facsimile 
(303) 236-4005. If you use a telecommunications device for the deaf 
(TDD), call the Federal Information Relay Service (FIRS) at (800) 877-
8339.

SUPPLEMENTARY INFORMATION:

Public Comments Solicited

    We intend that any final action resulting from this proposal will 
be as accurate and as effective as possible. Therefore, we solicit 
data, comments, new information, or suggestions from the public, other 
concerned governmental agencies, the scientific community, industry, or 
any other interested party concerning this revised proposed rule. 
Generally, we seek information, data, and comments concerning:
    (1) Survey results for Preble's meadow jumping mouse, as well as 
any studies that may show distribution, status, population size, or 
population trends;
    (2) Pertinent aspects of life history, ecology, and habitat use of 
Preble's meadow jumping mouse, especially those pertaining to its 
relationship to the western jumping mouse (Zapus princeps);
    (3) Current and foreseeable threats faced by the Preble's meadow 
jumping mouse in relation to the five factors (as defined in section 
4(a)(1) of the Act (16 U.S.C. 1531 et seq.));
    (4) Effects of current and foreseeable land management practices on 
Preble's meadow jumping mouse status, including conservation efforts;
    (5) Our analysis and conclusions regarding the conservation status 
of the Preble's meadow jumping mouse throughout all of its range, in 
particular information relative to the long-term security of existing 
populations of the subspecies in Wyoming.
    (6) Our analysis and conclusions regarding ``significant portion of 
its range'' in light of the March 14, 2007, Department of the Interior, 
Solicitor Memorandum opinion available at https://www.doi.gov/solicitor/
M37013.pdf;
    (7) The contribution of both the Wyoming and Colorado portions of 
the range to the status of the subspecies;
    (8) The range of the subspecies as defined in this proposal and the 
areas where the protections of the Act should remain in place (see 
``Significant Portion of the Range Where the Subspecies is Threatened'' 
for specific information solicited) and
    (9) The Sustainable Ecosystems Institute (SEI) report ``Evaluation 
of scientific information regarding Preble's meadow jumping mouse'' 
(available at https://www.fws.gov/mountain-prairie/species/mammals/
preble/) and other information concerning the taxonomic status of 
Preble's meadow jumping mouse.
    You may submit your comments and materials concerning this revised 
proposed rule by one of several methods (see ADDRESSES). If you use e-
mail to submit your comments, please submit them in ASCII file format 
and avoid the use of special characters and encryption. Please include 
``Attn: Preble's meadow jumping mouse'' in your e-mail subject header, 
preferably with your name and return address in the body of your 
message. If you do not receive a confirmation from the system that we 
have received your e-mail, contact us directly by calling our Colorado 
Field Office at (303) 236-4773. Please note that we must receive 
comments by the date specified in the DATES section in order to 
consider them in our final determination and that we will close out the 
e-mail address FW6--PMJM@fws.gov at the termination of the public 
comment period.
    Before including your address, phone number, e-mail address, or 
other personal identifying information in your comment, you should be 
aware that

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your entire comment--including your personal identifying information--
may be made publicly available at any time. While you can ask us in 
your comment to withhold your personal identifying information from 
public review, we cannot guarantee that we will be able to do so. We 
will always make submissions from organizations and businesses, and 
from individuals identifying themselves as representatives or officials 
of organizations and businesses, available for public inspection in 
their entirety.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this revised proposed rule, will be 
available for public inspection, by appointment, during normal business 
hours at the U.S. Fish and Wildlife Service Colorado Field Office, 134 
Union Blvd., Suite 670, Lakewood, CO 80228, (telephone (303) 236-4773) 
. We will take into consideration all substantive comments and any 
pertinent information we receive during the comment period on this 
revised proposed rule during the preparation of a final rulemaking. 
Accordingly, the final decision may differ from this proposal.

Open Houses and Public Hearings

    We will hold open houses and public hearings on the dates listed in 
the DATES section, and at the addresses listed in the ADDRESSES 
section, of this document. Anyone wishing to make an oral statement for 
the record at either of the public hearing is encouraged to provide a 
written copy of his or her statement and present it to us at the 
hearing. Persons wishing to make an oral statement at the public 
hearing may sign up only at the open house or at the public hearing; we 
will not reserve speaking time in advance of the open house. In the 
event that there is a large attendance, the time allotted for oral 
statements may be limited. Oral and written statements receive equal 
consideration. There are no limits on the length of written comments 
submitted to us. If you have any questions concerning the open house or 
public hearing, please contact Sharon Rose at (303) 236-4580. Persons 
needing reasonable accommodations in order to attend and participate in 
the open house or public hearing should contact Sharon Rose as soon as 
possible in order to allow sufficient time to process requests. Please 
call no later than 1 week before the hearing date. Information 
regarding this revised proposal is available in alternative formats 
upon request.

Previous Federal Actions

    We listed Preble's meadow jumping mouse as threatened under the Act 
on May 13, 1998 (63 FR 26517). We designated critical habitat for 
Preble's meadow jumping mouse on June 23, 2003 (68 FR 37275). On May 
22, 2001 (66 FR 28125), we adopted a final section 4(d) special rule 
for the Preble's meadow jumping mouse that provides exemptions from 
section 9 take prohibitions for certain rodent control activities, 
ongoing agricultural activities, maintenance and replacement of 
existing landscaping, and existing uses of water. On October 1, 2002 
(67 FR 61531), we amended this rule to provide exemptions for certain 
noxious weed control and ditch maintenance activities. The special 
rule, as amended, was scheduled to sunset May 22, 2004, but was made 
permanent on May 20, 2004 (69 FR 29101).
    In June 2000, the Service established the Preble's Meadow Jumping 
Mouse Recovery Team composed of scientists and stakeholders. In June 
2003, the Recovery Team provided their recommendations to the Service 
in the form of a draft recovery plan. This technical working draft was 
revised by the Service in November 2003. The Preliminary Draft Recovery 
Plan suggested long-term protection of: One large population (with June 
abundances of 2,500 or more individuals), two medium populations (with 
June abundances of 500-2,499 individuals), and six small populations 
(with evidence of occupancy; possibly 150 mice) within the North Platte 
River basin two large, three medium, and eighteen small populations 
within the South Platte River basin and one large population, and six 
small populations within the Arkansas River basin (Service 2003b, p. 
19-23). Recovery planning efforts were halted in December 2003 after 
new information became available questioning the taxonomic validity of 
the subspecies. While the availability of this document (hereafter 
referred to as the Preliminary Draft Recovery Plan (Service 2003b)) has 
not yet been announced in the Federal Register, it represents the best 
available information on the recovery needs of the subspecies.
    On December 23, 2003, we received two nearly identical petitions, 
from the State of Wyoming's Office of the Governor and Coloradans for 
Water Conservation and Development, seeking to remove Preble's meadow 
jumping mouse from the Federal List of Endangered and Threatened 
Wildlife (Freudenthal 2003; Sonnenberg 2003). The petitions maintained 
that Preble's meadow jumping mouse should be delisted based on the 
taxonomic revision suggested by Ramey et al. (2003) and new 
distribution, abundance, and trends data which suggested the subspecies 
was no longer threatened or endangered (Freudenthal 2003, p. 1; 
Sonnenberg 2003, p. 1).
    On March 31, 2004, we published a notice announcing a 90-day 
finding that the petitions presented substantial information indicating 
that the petitioned action may be warranted (69 FR 16944). On February 
2, 2005, we published a 12-month finding that the petitioned action was 
warranted, and a proposed rule to remove Preble's meadow jumping mouse 
from the Federal List of Endangered and Threatened Wildlife, and opened 
a 90-day public comment period (70 FR 5404). The proposed delisting was 
based upon a taxonomic revision suggested by Ramey et al. (2004a (a 
revision of Ramey et al. 2003)), which concluded that Preble's meadow 
jumping mouse should be synonymized with a neighboring subspecies 
(Ramey et al. 2004a, pp. 1, 13). Although this report remained 
unpublished and had received mixed peer reviews, we concluded that a 
lack of distinct genetic and morphologic differences suggested that 
Preble's meadow jumping mouse was likely not a valid subspecies of 
meadow jumping mouse (Zapus hudsonius). Considering the weight that we 
gave Ramey et al. (2004a) in the proposed delisting, verifying the 
results of this study prior to making a final decision on the proposal 
was a high priority of the Service (Williams 2004; Morgenweck 2005). As 
such, we contracted with the U.S. Geological Survey (USGS) to conduct 
additional genetic analysis of Preble's meadow jumping mouse and four 
neighboring subspecies of meadow jumping mice (U.S. Geological Survey 
2005, pp. 1-4).
    On January 25, 2006, USGS released its report concluding that 
Preble's meadow jumping mouse should not be synonymized with 
neighboring subspecies of meadow jumping mice (King et al. 2006a, pp. 
2, 29). On February 17, 2006, the Service extended the rulemaking 
process an additional 6 months as allowed under section 4(b)(6)(B)(i) 
of the Act because this USGS study indicated that there was substantial 
disagreement regarding the sufficiency or accuracy of the available 
data relevant to the determination contained in our proposed rule (71 
FR 8556). We reopened the comment period for an additional 60 days and 
announced that we intended to assemble a panel of experts to carefully 
review and assess the two studies.

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    On March 30, 2006, we published a notice of availability of the 
King et al. (2006a) and Ramey et al. (2005) data and extended the 
comment period on the proposed delisting rule an additional 30 days (71 
FR 16090). We then contracted with Sustainable Ecosystems Institute 
(SEI) to organize a scientific review panel to analyze, assess, and 
weigh the reasons why the data, findings, and conclusions of King et 
al. differ from the data, findings, and conclusions of Ramey et al. (as 
written in this sentence, and hereafter, ``Ramey et al.'' or ``King et 
al.'' without a modifying date refers to the overall work of these 
authors instead of a specific publication) (Service 2006, p. 14). On 
July 21, 2006, SEI delivered a final report to the Service (SEI 2006a).
    On September 26, 2006, the State of Wyoming submitted a 60-day 
notice of intent to sue over our failure to publish a final 
determination on our 2005 proposed delisting rule within the timeframes 
allowed by the Act. On January 24, 2007, the State of Wyoming filed a 
petition for review with the court. On June 22, 2007, the Service and 
the State of Wyoming reached a settlement agreement which required 
that, by October 31, 2007, we submit to the Federal Register for 
publication either (1) a withdrawal of our 2005 proposed delisting 
regulation; or (2) a new proposed regulation considering the Preble's 
meadow jumping mouse's taxonomy and the subspecies' threatened status 
in light of all current distribution, abundance, and trends data (State 
of Wyoming v. U.S. Department of the Interior, No. 07CV025J (District 
of Wyoming 2007)). If a new proposed regulation is deemed necessary, 
the Service is required to submit a final determination to the Federal 
Register no later than June 30, 2008.

Public Comments on the 2005 Proposed Rule

    From February 2, 2005, through May 3, 2005 (70 FR 5404, February 2, 
2005), and from February 17, 2006, through May 18, 2006 (71 FR 8556, 
February 17, 2006; 71 FR 16090, March 30, 2006), we solicited, from all 
interested parties, comments and information that might contribute to 
the final delisting determination for the Preble's meadow jumping 
mouse. We received a total of 67 written comments, including 28 
comments during the initial comment period and 39 during the reopened 
comment period. These included comments from: The Governor of the State 
of Wyoming; the Attorney General of the State of Wyoming; the Colorado 
Department of Natural Resources; U.S. Forest Service, Rocky Mountain 
Region; 6 comments from local governments; and 57 comments from 
individuals or groups. During the reopened comment period we also 
received a challenge under the Information Quality Act (44 U.S.C. 3516) 
to influential information disseminated by the Service during this 
rulemaking process. This challenge and our response are available at 
https://www.fws.gov/informationquality/. This response has been appealed 
and the appeal is currently under review by the Service. Because we 
received the original challenge during the open public comment period, 
these issues are considered public comments on our proposed rule.
    In accordance with our July 1, 1994, Interagency Cooperative Policy 
for Peer Review in Endangered Species Act Activities (59 FR 34270), we 
solicited five expert peer reviews of our proposed rule (70 FR 5404, 
February 2, 2005). We selected peer reviewers for expertise in 
genetics, systematics (the science of dealing with the diversity of 
organisms), and small mammals. We excluded previous peer reviewers of 
Ramey et al. and King et al. from this solicitation. Three of the 
experts approached provided comments (Hoekstra 2005; Kelt 2005; Spencer 
2005). After reopening the public comment period on February 17, 2006 
(71 FR 8556), we contacted the same five experts and invited them to 
provide additional comments given the availability of new information 
(i.e., King et al. 2006a). Two of these reviewers provided comments 
(Kelt 2006; Spencer 2006a).
    All previously submitted comments have been included in the public 
record and will be considered in the final determination regarding this 
proposal. Comments previously submitted need not be resubmitted. 
Additionally, all of the previously submitted comments and reviews 
relevant to the taxonomy discussion were made available to the SEI 
panel for its consideration. Substantive comments will be addressed in 
a series of issues and responses in our final determination.

General Information

    Meadow jumping mice (Zapus hudsonius) are small rodents with long 
tails, large hind feet, and long hind legs. Total length of an adult is 
approximately 187 to 255 millimeters (7 to 10 inches), with the tail 
comprising 108 to 155 millimeters (4 to 6 inches) of that length 
(Krutzsch 1954, p. 420; Fitzgerald et al. 1994, p. 291).
    Across their range, meadow jumping mice typically occur in moist 
habitats, including low undergrowth consisting of grasses, forbs, or 
both, in open wet meadows and riparian corridors, or where tall shrubs 
and low trees provide adequate cover (Krutzsch 1954, p. 351; Armstrong 
1972, p. 248; Jones et al. 1983, p. 238). Trainor et al. (2007, pp. 
471-472) found that high use areas for Preble's meadow jumping mouse 
tended to be close to creeks and were positively associated with the 
percentage of shrubs, grasses, and woody debris. Hydrologic regimes 
that support Preble's meadow jumping mouse habitat range from large 
perennial rivers such as the South Platte River to small drainages only 
1 to 3 meters (m) (3 to 10 feet (ft)) in width.
    Meadow jumping mice are primarily nocturnal or crepuscular (active 
during twilight), but also may be active during the day. The Preble's 
meadow jumping mouse uses uplands at least as far out as 100 m (330 ft) 
beyond the 100-year floodplain (Shenk and Sivert 1999a, p. 11; Ryon 
1999, p. 12; Schorr 2001, p. 14; Shenk 2004; Service 2003b, p. 26). 
While the Preble's meadow jumping mouse dispersal capabilities are 
thought to be limited, in one instance a Preble's meadow jumping mouse 
was documented moving as far as 1.1 kilometers (km) (0.7 mile (mi)) in 
24 hours (Ryon 1999, p. 12). The Preble's meadow jumping mouse 
typically enters hibernation between September and October and emerges 
the following May (Whitaker 1963, p. 5; Meaney et al. 2003).
    For additional information on the biology of this subspecies, see 
the May 13, 1998, final rule to list the Preble's meadow jumping mouse 
as threatened (63 FR 26517) and the June 23, 2003, final rule 
designating critical habitat (68 FR 37275).

Taxonomy

    The Preble's meadow jumping mouse is a member of the family 
Dipodidae (jumping mice) (Wilson and Reeder 1993, p. 499), which 
contains four extant genera. Two of these, Zapus (jumping mice) and 
Napaeozapus (woodland jumping mice), are found in North America (Hall 
1981, p. 841; Wilson and Ruff 1999, pp. 665-667).
    In his 1899 study of North American jumping mice, Edward A. Preble 
concluded the Zapus genus consisted of 10 species (Preble 1899, pp. 13-
41). According to Preble (1899, pp. 14-21), Z. hudsonius (the meadow 
jumping mouse) included five subspecies. Preble (1899, pp. 20-21) 
classified all specimens of the meadow jumping mouse from North Dakota, 
Montana, South Dakota, Wyoming, Nebraska, Colorado, and Missouri as a 
single subspecies, Z. hudsonius campestris. Cockrum and Baker (1950, 
pp. 1-4) later designated specimens from Nebraska,

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Kansas, and Missouri as a separate subspecies, Z. h. pallidus.
    Krutzsch (1954, pp. 352-355) revised the taxonomy of the Zapus 
genus after studying morphological characteristics of 3,600 specimens. 
This revision reduced the number of species within this genus from 10 
to 3, including Z. hudsonius (the meadow jumping mouse), Z. princeps 
(the western jumping mouse), and Z. trinotatus (the Pacific jumping 
mouse). According to Krutzsch (1954, pp. 385-453), the meadow jumping 
mouse included 11 subspecies.
    Krutzsch (1954, pp. 452-453) described and named the subspecies 
Preble's meadow jumping mouse (Zapus hudsonius preblei) based on 
geographic separation and morphological (physical form and structure of 
an organism) differences. Krutzsch (1954, pp. 452-453) discussed the 
presence of physical habitat barriers and the lack of known 
intergradation (merging gradually through a continuous series of 
intermediate forms or populations) between the Preble's meadow jumping 
mouse, known only from eastern Colorado and southeastern Wyoming, and 
other identified subspecies of meadow jumping mice ranging to the east 
and north. Additionally, Krutzsch (1954, pp. 452-453) evaluated the 
morphometric characteristics of 4 adult and 7 non-adult specimens. 
Acknowledging the small number of samples upon which his conclusion was 
based, Krutzsch (1954, p. 453) nonetheless concluded that the 
differences between Preble's meadow jumping mouse and neighboring 
meadow jumping mice was considerable and enough to warrant a 
subspecific designation.
    In Krutzsch's analysis, the subspecies neighboring Preble's meadow 
jumping mouse included Z. h. campestris in northwestern Wyoming, 
southwestern South Dakota, and southeastern Montana; Z. h. intermedius 
in North Dakota, and northwestern, central, and eastern South Dakota; 
and Z. h. pallidus (Cockrum and Baker 1950) in Nebraska, Kansas, and 
Missouri (Krutzsch 1954, pp. 441-442, 447-452). Among recognized 
subspecies, Krutzsch (1954, p. 452) found that Preble's meadow jumping 
mouse most closely resembled Z. h. campestris from northeastern 
Wyoming, but documented differences in coloration and skull 
characteristics.
    In 1981, Hafner et al. (1981, p. 501) identified Zapus hudsonius 
luteus from Arizona and New Mexico as the 12th subspecies of meadow 
jumping mouse. This population had previously been assumed to be a 
subspecies of western jumping mouse (Krutzsch 1954, pp. 406-407; Hall 
and Kelson 1959, pp. 774-776; Jones 1981, p. iv).
    Krutzsch's description (1954) as modified by Hafner et al. (1981, 
p. 501), with 12 subspecies of meadow jumping mice, was generally 
accepted by most small mammal taxonomists for the past half-century 
(Hall and Kelson 1959, pp. 771-774; Long 1965, pp. 664-665; Armstrong 
1972, pp. 248-249; Whitaker 1972, pp. 1-2; Hall 1981, pp. 841-844; 
Jones et al. 1983, pp. 238-239; Clark and Stromberg 1987, p. 184; 
Wilson and Reeder 1993, p. 499; Hafner et al. 1998, pp. 120-121; Wilson 
and Ruff 1999, pp. 666-667).

Other Taxonomic Information Available Prior to Listing

    As part of a doctoral dissertation, Jones (1981, pp. 4-29, 229-303, 
386-394, 472) analyzed the morphology of 9,900 specimens within the 
Zapus genus from across North America, including 39 Preble's meadow 
jumping mouse specimens. Jones's dissertation (1981, p. 144) concluded 
that the Pacific jumping mouse was not a valid taxon and suggested 
reducing the number of species in the genus to two (the western jumping 
mouse and the meadow jumping mouse). At the subspecific level, Jones 
(1981, pp. V, 303) concluded that no population of meadow jumping mouse 
was sufficiently isolated or distinct to warrant subspecific status. 
Regarding the Preble's meadow jumping mouse, Jones (1981, pp. 288-289) 
wrote that ``No named subspecies is geographically restricted by a 
barrier, with the possible exception of Z. h. preblei [Preble's meadow 
jumping mouse]'' which ``appears to be isolated,'' but that ``no 
characteristics indicate that these populations have evolved into a 
separate taxon.'' Jones did not compare the Preble's meadow jumping 
mouse to Z. h. campestris, a neighboring subspecies, nor did he conduct 
statistical tests of morphology between the Preble's meadow jumping 
mouse and any other subspecies. Jones's (1981) findings were not 
published in a peer-reviewed journal and were not incorporated into the 
formal jumping mouse taxonomy, leaving his conclusions difficult to 
evaluate.
    Prior to listing, the Colorado Division of Wildlife (CDOW) 
contracted for a genetic analysis of the Preble's meadow jumping mouse 
(Riggs et al. 1997). Riggs et al. (1997, p. 1) examined a small number 
of base-pairs (433) in one region of the mitochondrial deoxyribonucleic 
acid (mtDNA) (maternally inherited genetic material) across 5 
subspecies of meadow jumping mouse (92 specimens). This study concluded 
that the Preble's meadow jumping mouse specimens formed a homogenous 
group recognizably distinct from other nearby populations of meadow 
jumping mice (Riggs et al. 1997, p. 12). At the request of the Service, 
Hafner (1997, p. 3) reviewed the Riggs study, inspected Riggs' original 
sequence data, and agreed with its conclusions. The Riggs et al. (1997) 
results were not published in a peer-reviewed journal. Prior to 
listing, this study was the only available information concerning the 
genetic uniqueness of the Preble's meadow jumping mouse.
    Our original listing determined that Krutzsch's (1954) revision of 
the meadow jumping mouse species, including the description of the 
Preble's meadow jumping mouse, was widely supported by the scientific 
community as indicated by the available published literature (63 FR 
26517, May 13, 1998). Our 1998 determination weighed the information in 
unpublished reports, such as Jones (1981), and public comments on the 
rule and found that they did not contain enough scientifically 
compelling information to suggest that revising the existing taxonomy 
was appropriate (63 FR 26517, May 13, 1998). Our 1998 conclusion was 
consistent with Service regulations that require us to rely on standard 
taxonomic distinctions and the biological expertise of the Department 
and the scientific community concerning the relevant taxonomic group 
(50 CFR 424.11).

Taxonomic Information Solicited After Listing

    In July 2003, we entered into a cooperative agreement with the 
Denver Museum of Natural Science (DMNS) to determine if the Preble's 
meadow jumping mouse was a unique subspecies relative to other nearby 
subspecies of meadow jumping mice (Service 2003a, pp. 1-2). This task 
was a priority of the Recovery Team (Service 2003a, pp. 1-2; Service 
2003b, pp. iv, 38, 43, 76). In December 2003, we received a draft 
report from the DMNS examining the uniqueness of the Preble's meadow 
jumping mouse relative to other nearby subspecies of meadow jumping 
mice (Ramey et al. 2003). In August 2005, an expanded version of this 
original report was published in the journal ``Animal Conservation'' 
(Ramey et al. 2005). This publication included an examination of 
morphometric differences, mtDNA, and microsatellite DNA (a short, 
noncoding DNA sequence, usually 2 to 5 base-pairs, that is repeated 
many times within the genome of an organism). Ramey et al. (2005, pp. 
339-341) also examined the literature for evidence of

[[Page 62996]]

ecological exchangeability among subspecies (a test of whether 
individuals can be moved between populations and can occupy the same 
ecological niche).
    Ramey et al.'s morphometric analysis tested 9 skull measurements of 
40 Preble's meadow jumping mice, 40 Z. h. campestris, and 37 Z. h. 
intermedius specimens (Ramey et al. 2005, p. 331). Their results did 
not support Krutzsch's (1954, p. 452) original description of the 
Preble's meadow jumping mouse as ``averaging smaller in most cranial 
measurements'' (Ramey et al. 2005, p. 334). Ramey et al. (2005, p. 334) 
found that only one cranial measurement was significantly smaller, 
while two cranial measurements were significantly larger.
    Ramey et al. examined a small number of base-pairs (346) in 1 
region of the mtDNA across 5 subspecies of meadow jumping mice (205 
specimens) (Ramey et al. 2005, pp. 331-332, 335). Ramey et al. (2005, 
p. 335, 338) found low levels of difference between the Preble's meadow 
jumping mouse and neighboring subspecies. Their data demonstrated that 
all of the mtDNA haplotypes (alternate forms of a particular DNA 
sequence or gene) found in the Preble's meadow jumping mouse were also 
found in Z. h. campestris. The mtDNA data demonstrated evidence of 
recent gene flow between the Preble's meadow jumping mouse and 
neighboring subspecies (Ramey et al. 2005, p. 338).
    Ramey et al. (2005, pp. 333-334, 338) analyzed a small number (5) 
of microsatellite loci (the specific position of a gene or other 
chromosomal marker) across 5 subspecies of meadow jumping mice (195 
specimens). Ramey et al. (2005, p. 340) concluded that these results 
were consistent with morphometric and mtDNA results.
    Based on morphometrics, mtDNA, and microsatellites data, and a lack 
of recognized adaptive differences, Ramey et al. (2005, p. 340) 
suggested synonymizing the Preble's meadow jumping mouse and Z. h. 
intermedius with Z. h. campestris.
    Prior to publication of Ramey et al. (2005) in ``Animal 
Conservation,'' the CDOW and the Service solicited 16 peer reviews of 
the 2004 draft report provided to the Service (Ramey et al. 2004a). 
Fourteen of these reviewers provided comments (Armstrong 2004; Ashley 
2004; Bradley 2004; Conner 2004; Crandall 2004; Douglas 2004; Hafner 
2004; Meaney 2004; Mitton 2004; Oyler-McCance 2004; Riddle 2004; Sites 
2004; Waits 2004; White 2004). In 2005, the Service approached the same 
16 experts to review Ramey et al. 2004b (an expansion of Ramey et al. 
2004a). Eleven of these reviewers provided comments (Ashley 2005; Baker 
and Larsen 2005; Bradley 2005; Crandall 2005; Douglas 2005; Hafner 
2005; Maldonado 2005; Mitton 2005; Oyler-McCance 2005; Waits 2005; 
White 2005). In August 2006, ``Animal Conservation'' published two 
critiques of Ramey et al. (2005) (Martin 2006; Vignieri et al. 2006) 
and two responses (Crandall 2006b; Ramey et al. 2006a).
    While many of the reviewers supported the findings of Ramey et al. 
(Baker and Larsen 2005; Bradley 2004, 2005; Crandall 2004, 2005; Hafner 
2004; Maldonado 2005; Meaney 2004; Mitton 2004, 2005; Riddle 2004; 
Sites 2004; Waits 2004, 2005), the reviews raised a number of important 
issues. Some of the most significant issues identified included: (1) 
Reliance upon museum specimens which can be prone to contamination 
(Douglas 2004, 2005; Maldonado 2005); (2) the reliability of, and 
failure to validate, specimens' museum tag locality (and thus 
subspecies) identification (Ashley 2005; Douglas 2004, 2005; Hafner 
2004; Oyler McCance 2004, 2005); (3) reliance upon a small portion of 
mtDNA (Ashley 2004, 2005; Baker and Larsen 2005; Crandall 2004, 2005; 
Douglas 2004, 2005; Hafner 2005; Maldonado 2005; Oyler-McCance 2004, 
2005; Riddle 2004; Sites 2004; Waits 2004, 2005); (4) the small number 
of microsatellite DNA loci examined (Vignieri et al. 2006, p. 241); (5) 
the criteria used and factors considered to test taxonomic validity as 
well as alternative interpretations of the data (Ashley 2004; Conner 
2004; Douglas 2004, 2005; Hafner 2005; Oyler-McCance 2004, 2005; 
Vignieri et al. 2006, pp. 241-242; White 2004); (6) whether the authors 
used an appropriate outgroup (a closely related group that is used as a 
rooting point of a phylogenetic tree) (Douglas 2004); (7) the sampling 
regime and its impact on the analysis (Maldonado 2005; Oyler-McCance 
2004); (8) failure to test all of the morphological characters examined 
by Krutzsch (1954) (Vignieri et al. 2006, p. 238); (9) an inadequate 
evaluation of ecological exchangeability and habitat differences among 
subspecies (Ashley 2004; Conner 2004; Douglas 2004; Meaney 2004; Mitton 
2004; Oyler-McCance 2004, 2005; Sites 2004; Vignieri et al. 2006, p. 
238; Waits 2004, 2005); and (10) failure to consider the Preble's 
meadow jumping mouse's geographic isolation (Vignieri et al. 2006, pp. 
237-238). Collectively, these critiques indicated that delisting based 
on the conclusions of Ramey et al. alone might be premature.
    Because the proposed rule to delist the Preble's meadow jumping 
mouse relied solely upon an unpublished report (Ramey et al. 2004a) 
that had received mixed peer reviews (see above), verifying these 
results was a high priority of the Service (Morgenweck 2005; Williams 
2004). Thus, in 2006, the Service contracted with USGS to conduct an 
independent genetic analysis of several meadow jumping mouse subspecies 
(U.S. Geological Survey 2005, pp. 1-4). The USGS study concluded that 
the Preble's meadow jumping mouse should not be synonymized with 
neighboring subspecies (King et al. 2006a, pp. 2, 29). An expanded 
version of this report was published in the journal ``Molecular 
Ecology'' (King et al. 2006b). This publication included an examination 
of microsatellite DNA, 2 regions of mtDNA, and 15 specimens critical to 
the conclusions of Ramey et al. (2005).
    King et al.'s (2006b, p. 4336) microsatellite analysis examined 
approximately 4 times the number of microsatellite loci (21) and 1\1/2\ 
times more specimens (348 specimens) than Ramey et al. (2005) across 
the same 5 subspecies of meadow jumping mice. King et al. (2006b, p. 
4337) concluded that their microsatellite data demonstrated a strong 
pattern of genetic differentiation between the Preble's meadow jumping 
mouse and neighboring subspecies. King et al. (2006b, pp. 4336-4341) 
also reported that multiple statistical tests of the microsatellite 
data verified this differentiation.
    In their evaluation of mtDNA, King et al. (2006b, p. 4341) examined 
approximately 4 times the number of base-pairs across 2 regions (374 
control region and 1,006 cytochrome-B region base-pairs) and 1\1/2\ 
times more specimens (320 specimens for the control region analysis and 
348 for the cytochrome-B analysis) than Ramey et al. (2005) across the 
same 5 subspecies of meadow jumping mice. King et al. (2006b, p. 4341) 
concluded that these data suggested strong, significant genetic 
differentiation among the five subspecies of meadow jumping mice 
surveyed. Additionally, their results indicated that the Preble's 
meadow jumping mouse did not share haplotypes with any neighboring 
subspecies (King et al. 2006b, p. 4341). Such haplotype sharing had led 
Ramey et al. to previously conclude that the Preble's meadow jumping 
mouse was not unique; specifically, Ramey et al. concluded that because 
all of the Preble's meadow jumping mouse haplotypes were found in Z. h. 
campestris, the Preble's meadow jumping mouse was a less genetically 
variable population of Z. h. campestris

[[Page 62997]]

(Ramey et al. 2004a, pp. 1, 9; 2005, p. 335). Because of these 
conflicting results, King et al. (2006b, pp. 4355-4357) reexamined 15 
specimens from the University of Kansas Museum collection relied upon 
by Ramey et al. in determining that neighboring subspecies shared 
haplotypes. Among the specimens reported to contain the Preble's meadow 
jumping mouse's haplotypes by Ramey et al. (2005, pp. 335-336), King et 
al. (2006b, p. 4357) found that the results could not be repeated. If 
these specimens were removed from the analysis, neither study would 
illustrate haplotype sharing between the Preble's meadow jumping mouse 
and neighboring subspecies. King et al. (2006b, p. 4357) concluded that 
``these findings have identified the presence of a systemic error in 
the control region data reported by Ramey et al. (2005)'' and ``calls 
into question all of the results of Ramey et al. (2005) based on the 
mtDNA genome and prevents analysis of the combined data.'' King et al. 
(2006, p. 4357) noted that possible reasons for the difference in 
sequences included contamination, mislabeling of samples, or other 
procedural incongruity.
    Overall, King et al. (2006b, p. 19) concluded that there was 
considerable genetic differentiation among all five subspecies and 
found no evidence to support the proposal to synonymize the Preble's 
meadow jumping mouse, Z. h. campestris, and Z. h. intermedius.
    Prior to its release, King et al. (2006a) underwent an internal 
peer review per USGS policy (U.S. Geological Survey 2003, pp. 3, 6, 12, 
28-33). In an effort to provide consistent, comparable reviews, we 
solicited peer reviews from the same 16 reviewers asked to review Ramey 
et al. (2004a, 2004b). Nine of the experts provided comments (Armstrong 
2006; Ashley 2006; Bradley 2006; Crandall 2006a; Douglas 2006; Hafner 
2006; Maldonado 2006; Oyler-McCance 2006; Riddle 2006). Some of the 
most significant issues raised included the sampling regime and its 
impact on the analysis (Armstrong 2006; Ashley 2006; Crandall 2006a; 
Douglas 2006; Oyler-McCance 2006; Riddle 2006); and the criteria used 
and factors considered to test taxonomic validity and alternative 
interpretations of the data (Bradley 2006; Crandall 2006a).
    Given the discrepancies between the Ramey et al. and King et al. 
reports, we contracted for a scientific review to analyze, assess, and 
weigh the reasons why the data, findings, and conclusions of the two 
studies differed (Service 2006, p. 14). Following an open and 
competitive bid process, we selected SEI as the contractor (Service 
2006).
    SEI assembled a panel of experts with the necessary scientific 
expertise in genetics and systematics (SEI 2006a, p. 7). The panelists 
reviewed, discussed, and evaluated all of the literature relevant to 
this issue, including published literature, unpublished reports, third-
party critiques, and other materials suggested by interested parties 
(SEI 2006a, pp. 48-55). Additionally, the panel examined and reanalyzed 
the raw data (SEI 2006a, pp. 8, 21) used by Ramey et al. and King et 
al., including the mtDNA data, microsatellite DNA data, and original 
sequence chromatograms (automated DNA sequence data output recordings) 
(SEI 2006a, pp. 8, 23). The scientific review panel was open to the 
public and allowed for interactions among panel members, Dr. King, Dr. 
Ramey, other scientists, and the public.
    In July 2006, SEI delivered a report outlining their conclusions to 
the Service (SEI 2006a). Although the panelists were not obligated to 
reach a consensus, they did not disagree on any substantive or 
stylistic issues (SEI 2006a, p. 9). Thus, the report represented the 
consensus of all three panelists, as well as the individual opinions of 
each panelist. The panel organized its evaluation into four sections 
corresponding with the different types of scientific evaluations 
performed, including morphology, ecological exchangeability, mtDNA, and 
microsatellite DNA. The panel's findings with regard to each are 
summarized briefly below. The full report is available for review at 
https://www.fws.gov/mountain-prairie/species/mammals/preble/Prebles_
SEI_report.pdf.
    Morphology: Although Ramey et al. (2005) examined two of the seven 
morphological characters identified by Krutzsch (1954, pp. 452-453), 
the panel found that all seven of these characters should have been 
reexamined in order to support the proposed taxonomic revision. The 
panel also concluded that the type specimen (a single specimen 
designated as the type by the original author at the time of 
publication of the original description of a taxon) of each taxon 
should have been included in the analysis. The panel's conclusion was 
that an insufficient test of the morphological definition of the 
Preble's meadow jumping mouse had been conducted to support the 
synonymy of the Preble's meadow jumping mouse with other subspecies 
(SEI 2006a, p. 41).
    Ecological Exchangeability: The panel concluded that no persuasive 
evidence was presented regarding ecological exchangeability, and that 
the ecological exchangeability of the subspecies remains unknown (SEI 
2006a, p. 41).
    MtDNA: The panel noted that data provided by Ramey et al. (2005) 
and King et al. (2006b) differed in geographic sampling strategy, 
amount of sequence data examined, aspects of the analysis, and quality 
(SEI 2006a, p. 41). All of these could help explain why the two studies 
came to differing conclusions. However, the panel noted that the most 
significant difference between the two studies in terms of mtDNA was 
whether the Preble's meadow jumping mouse shared any mtDNA haplotypes 
with other subspecies of meadow jumping mice. Upon review of the raw 
data, the panel found evidence of contamination within some of the key 
sequences reported by Ramey et al. The panel concluded that there was 
no reliable evidence of any haplotype sharing (SEI 2006a, p. 42). The 
panel further determined that if these conflicting mtDNA sequences were 
removed from consideration, the two studies' mtDNA data would largely 
agree (SEI 2006a, p. 32). The panel also suggested that because the 
western jumping mouse and the meadow jumping mouse are distantly 
related, western jumping mouse may perform poorly as an outgroup, 
leading to poor resolution of relationships among meadow jumping mouse 
subspecies. While both Ramey et al. and King et al. used this outgroup, 
unrooted analysis showed clearer structuring between the subspecies 
(SEI 2006a, p. 42).
    Microsatellite DNA: The panel found that the two microsatellite 
datasets contain similar information. The panel pointed out that both 
the Ramey et al. (2005) and King et al. (2006) microsatellite data, as 
well as Crandall and Marshall's (2006) reanalysis of these data, 
strongly support a statistically significant independent cluster that 
corresponds to the Preble's meadow jumping mouse, providing support for 
a distinct subspecies (SEI 2006a, pp. 42-43). The panel indicated that 
while the microsatellite data alone did not make a strong case for 
evolutionary significance, in concert with the mtDNA data (discussed 
above), the two datasets corroborate the distinctness of the Preble's 
meadow jumping mouse (SEI 2006a, pp. 43).
    The panel's overall conclusion was that the available data are 
broadly consistent with the current taxonomic status of the Preble's 
meadow jumping mouse as a valid subspecies and that no evidence was 
presented that critically challenged its status (SEI 2006a, p. 4). In 
August 2006, Ramey et al. (2006c) submitted a statement to the Service 
disputing the findings and conclusions

[[Page 62998]]

of the SEI report. No new data or analyses were presented in this 
statement, and the panel previously considered most of the contentions 
(Ramey et al. 2003, 2004a, 2004b, 2005, 2006a, 2006b; SEI 2006a, 2006b, 
2006c). Other evaluations of the available literature and data include 
Ramey et al. (in press), King et al. (in review), Crandall and Marshall 
(2006), Spencer (2006b), and Cronin (2007).

Taxonomic Conclusions

    When listed in 1998, the Preble's meadow jumping mouse was widely 
recognized as a valid subspecies by the scientific community (Hall and 
Kelson 1959, pp. 771-774; Long 1965, pp. 664-665; Armstrong 1972, pp. 
248-249; Whitaker 1972, pp. 1-2; Hall 1981, pp. 841-844; Jones et al. 
1983, pp. 238-239; Clark and Stromberg 1987, p. 184; Wilson and Reeder 
1993, p. 499; Hafner et al. 1998, pp. 120-121; Wilson and Ruff 1999, 
pp. 666-667). At the time of listing, Krutzsch (1954) represented the 
best available information on the taxonomy of the Preble's meadow 
jumping mouse (63 FR 26517, May 13, 1998). Our 1998 conclusion was 
consistent with Service regulations that require us to rely on standard 
taxonomic distinctions and the biological expertise of the Department 
and the scientific community concerning the relevant taxonomic group 
(50 CFR 424.11). However, when the best available science indicates 
that the generally accepted taxonomy may be in error, the Service must 
rely on the best available science (Center for Biological Diversity, et 
al., v. Robert Lohn, et al., 296 F. Supp. 2d. 1223 W.D. Wash. 2003). 
Such considerations led to our February 2, 2005, proposal to delist 
Preble's based upon information which questioned the subspecies' 
taxonomic validity (70 FR 5404).
    We now determine the best scientific and commercial data available 
support the conclusion that the Preble's meadow jumping mouse is a 
valid subspecies. Specifically, the Preble's meadow jumping mouse's 
geographic isolation from other subspecies of meadow jumping mice 
(Krutzsch 1954, pp. 452-453; Long 1965, pp. 664-665; SEI 2006a, p. 34) 
has resulted in the accretion of considerable genetic differentiation 
(King et al. 2006b, pp. 4336-4348; SEI 2006a, pp. 41-43). The available 
data suggest that the Preble's meadow jumping mouse meets or exceeds 
numerous, widely accepted subspecies definitions (Mayr and Ashlock 
1991, pp. 43-45; Patten and Unitt 2002, pp. 26-34; SEI 2006a, p. 44). 
In reaching this conclusion, we do not use a presumption that we must 
rely on the established taxonomy in the absence of conclusive data to 
the contrary (see SEI report at p. 39). In Therefore, after a review of 
all available information, we have determined that the taxonomic 
revision for the Preble's meadow jumping mouse suggested in our 
proposed delisting rule (70 FR 5404, February 2, 2005) is no longer 
appropriate.

Historical Range and Recently Documented Distribution

    Generally, the Preble's meadow jumping mouse range includes 
portions of the North Platte, the South Platte, and the Arkansas River 
basins (Long 1965, p. 665; Armstrong 1972, pp. 248-249; Clark and 
Stromberg 1987, p. 184; Fitzgerald et al. 1994, p. 293; Clippinger 
2002, p. 20).
    At the time of listing, we described the historical range in 
Wyoming as including five counties (Albany, Laramie, Platte, Goshen, 
and Converse), but cited only two sites with recent reports of jumping 
mice likely to be the Preble's meadow jumping mouse. We cited a study 
by Compton and Hugie (1993, p. 6) suggesting the subspecies might be 
extirpated in Wyoming and comments by the Wyoming Game and Fish 
Commission that the Preble's meadow jumping mouse had likely been 
extirpated from most or all of its historical range in Wyoming (Wichers 
1997).
    At the time of listing, we assumed that most of the subspecies' 
current range was in Colorado. Within Colorado, the final listing rule 
described a presumed historical range including portions of ten 
counties (Adams, Arapahoe, Boulder, Denver, Douglas, El Paso, Elbert, 
Jefferson, Larimer, and Weld) and cited recent trapping efforts that 
documented the subspecies in seven of these ten counties (Boulder, 
Douglas, El Paso, Elbert, Jefferson, Larimer, and Weld).
    Since we listed the Preble's meadow jumping mouse in 1998, 
knowledge about distribution of the subspecies has grown substantially. 
Numerous trapping surveys conducted during the last 9 years in Wyoming 
and Colorado have documented the subspecies' presence or likely absence 
at locations of suitable habitat. While many recent trapping efforts 
have been at locations with no record of historical surveys, most have 
been within the presumed historical range of the Preble's meadow 
jumping mouse or in adjacent drainages where habitat and elevation 
appeared suitable. Thus, the recent increase in sites of Preble's 
meadow jumping mouse occurrence likely represents an improvement in our 
understanding of the subspecies range as a result of increased trapping 
effort rather than any actual expansion of the range of the Preble's 
meadow jumping mouse.
    In Wyoming, recent captures and confirmed identification have 
expanded our knowledge of the distribution of the Preble's meadow 
jumping mouse from the two sites documented at the time of listing to 
include over two dozen new plains, foothills, and montane sites east of 
the Laramie Mountains in the North Platte River basin, and presence in 
the Upper Laramie River drainage in Albany County (Taylor 1999; Service 
2007). Post-listing activities have identified many additional sites 
occupied by the subspecies. These data also reveal that the Preble's 
meadow jumping mouse occurs in four of the five counties described as 
the likely historical range at the time of listing including Albany, 
Laramie, Platte, and Converse Counties.
    At the time of listing, we discussed how increased trapping efforts 
in Colorado had recently documented distribution in Elbert, Larimer, 
and Weld Counties. We also suggested other sites where trapping should 
occur to determine if the Preble's meadow jumping mouse were present. 
Additional trapping since listing has expanded the documented 
distribution of the Preble's meadow jumping mouse in Colorado to 
include: additional foothill and montane sites along the Front Range in 
Larimer, Boulder, Jefferson, and Douglas Counties; previously untrapped 
rural prairie and foothill streams in southern Douglas County and 
adjacent portions of Elbert County; and additional prairie and foothill 
streams in northwestern El Paso County. Although we have identified 
some additional sites occupied by the Preble's meadow jumping mouse, 
over 80 percent of such trapping efforts throughout Colorado have 
failed to capture Preble's meadow jumping mice (as illustrated in 
Figure 1 below) (Service 2007).
BILLING CODE 4310-55-P

[[Page 62999]]

[GRAPHIC] [TIFF OMITTED] TP07NO07.000

BILLING CODE 4310-55-C
    These negative trap results suggest that the subspecies is rare or 
possibly extirpated from many portions of the subspecies' historical 
range in Colorado.

[[Page 63000]]

Areas where the subspecies is presumed extirpated is discussed in the 
Factor A discussion below.
    The Preble's meadow jumping mouse has now been recently documented 
in portions of Albany, Laramie, Platte, and Converse Counties in 
Wyoming; and in portions of Boulder, Douglas, El Paso, Elbert, 
Jefferson, Larimer, and Weld Counties in Colorado (Figure 1). The North 
Platte River at Douglas, Wyoming, marks the northernmost confirmed 
location for the Preble's meadow jumping mouse. Specimens from Colorado 
Springs, Colorado, mark the southernmost documented location of the 
Preble's meadow jumping mouse.
    The Preble's meadow jumping mouse is generally found at elevations 
between 1,420 m (4,650 ft) and 2,300 m (7,600 ft), although elevations 
vary across the range of the subspecies. At the lower end of this 
elevation gradient, the semi-arid climate of southeastern Wyoming and 
eastern Colorado limits the extent of riparian corridors and restricts 
the range of the Preble's meadow jumping mouse (Beauvais 2001, p. 3). 
The Preble's meadow jumping mouse is likely an Ice Age relic; once the 
glaciers receded from the Front Range of Colorado and the foothills of 
Wyoming and the climate became drier, the Preble's meadow jumping mouse 
was confined to riparian systems where moisture was more plentiful 
(Fitzgerald et al. 1994, p. 1994; Smith et al. 2004, p. 293). The 
eastern boundary for the subspecies is likely defined by the dry 
shortgrass prairie, which may present a barrier to eastward expansion 
(Beauvais 2001, p. 3). In Wyoming, the Preble's meadow jumping mouse 
has not been found east of Cheyenne, Laramie County (Beauvais 2001, p. 
3). Habitat modeling and trapping suggest the subspecies may not occur 
in Wyoming's Goshen, Niobrara, and eastern Laramie Counties (Keinath 
2001, p. 7). In Colorado, the Preble's meadow jumping mouse has not 
been found on the extreme eastern plains (Clippinger 2002, pp. 20-21).
    At the higher elevations, discerning the status of the Preble's 
meadow jumping mouse is complicated by the overlap in the ranges of the 
Preble's meadow jumping mouse and the western jumping mouse (Long 1965, 
pp. 665-666; Clark and Stromberg 1987, pp. 184-187; Schorr 1999, p. 3; 
Bohon et al. 2005; Schorr et al. 2007, p. 5). Field differentiation 
between the Preble's meadow jumping mouse and the western jumping mouse 
is difficult (Conner and Shenk 2003a, p. 1456). Generally, the western 
jumping mouse occurs in the montane and subalpine zones and the 
Preble's meadow jumping mouse occurs lower, in the plains and foothills 
(Smith et al. 2004, p. 10). Using this as a guide, many jumping mice 
were trapped and released without being conclusively identified as 
either a Preble's meadow jumping mouse or a western jumping mouse. 
Because western jumping mice have been verified at elevations well 
below the upper elevation limit of the Preble's meadow jumping mouse 
(Smith et al. 2004, p. 11), this leads to difficulty in making 
assumptions regarding identification based on elevation. Drainages 
where overlapping ranges have been verified include the Glendo 
Reservoir, Lower Laramie, Upper Laramie, and Horse Creek drainages in 
Wyoming (Conner and Shenk 2003b, pp. 31-35; Meaney 2003; King 2006a; 
King 2006b; King et al. 2006b, pp. 4351-4353); and the Cache La Poudre, 
Big Thompson, and Upper South Platte River drainage in Colorado (Bohon 
et al. 2005; King 2005; King 2006a; King et al. 2006b, pp. 4351-4353; 
Schorr et al. 2007).
    Size, external morphology, dentition, skull measurements, and 
genetic analysis can all be used to differentiate meadow jumping mice 
(including the Preble's meadow jumping mouse) from western jumping mice 
(Krutzsch 1954, pp. 351-384; Klingenger 1963, p. 252; Riggs et al. 
1997, pp. 2-8; Conner and Shenk 2003a; Ramey et al.; King et al.). The 
following description of the Preble's meadow jumping mouse's current 
documented distribution and status is based primarily on individuals 
positively identified as Preble's meadow jumping mice, with emphasis on 
locations where individual mice have been identified by genetic 
analysis or discriminant function analysis (DFA) (analysis of cranial 
measurements and an anterior medial toothfold characteristic) (Conner 
and Shenk 2003a). Information regarding individual mice and capture 
locations can be found in Riggs et al. (1997, pp. 8-11, A2-A5), Conner 
and Shenk (2003b, pp. 31-35), and King et al. (2006b, pp. 4351-4353). 
Positive identification of individual mice is most important in areas 
where both the Preble's meadow jumping mouse and the western jumping 
mouse occur. Overlap appears to occur in most of Wyoming's occupied 
drainages. In Colorado, with few exceptions, jumping mice below 2,050 m 
(6,700 ft) have been positively identified as Preble's meadow jumping 
mice. Above 2,050 m (6,700 ft) in Colorado, Preble's meadow jumping 
mice and western jumping mice are known to have an overlapping 
distribution in the Cache La Poudre, Big Thompson, and Upper South 
Platte River drainages.
    Below is a summary of recent (since 1980) trapping data by drainage 
(as defined by 8-digit USGS hydrologic units), within both Wyoming 
(e.g., the North and South Platte River basins) and Colorado (e.g., the 
South Platte River and Arkansas River basins). Although trapping data 
is important because it absolutely confirms the occurrence of jumping 
mice at particular locations, as discussed in detail below, trapping 
data is one of several lines of evidence we use to estimate the actual 
current range of the subspecies. Records have been compiled by the 
Service (2007) in coordination with the Wyoming Natural Diversity 
Database, State of Wyoming, and CDOW. In addition, Figure 1 above 
illustrates all recent Preble's meadow jumping mouse specimens, 
historical (pre-1980) locations no longer believed to be occupied, and 
recent negative trapping efforts. Given wide areas of overlapping range 
in Wyoming, we require all Wyoming specimens to be confirmed as 
Preble's meadow jumping mice in order to be considered below. In 
Colorado, jumping mice are considered Preble's meadow jumping mice when 
identification is confirmed or if they occur in areas where western 
jumping mice are not known.
    North Platte River Basin, Wyoming. In the North Platte River basin, 
occurrence of the Preble's meadow jumping mouse has been confirmed in 
four Wyoming counties (Converse, Platte, Albany, and Laramie) as 
reported by drainage below.
    The Middle North Platte drainage represents the northern extent of 
the reported Preble's meadow jumping mouse range; however, trapping 
surveys have been quite limited and generally at high elevations. 
Although several jumping mice have been trapped in this drainage, these 
specimens have not been confirmed as Preble's meadow jumping mice.
    In the Glendo Reservoir drainage, the Preble's meadow jumping mouse 
is known from several locations, including along the North Platte River 
at Douglas (King 2006b), Cottonwood Creek and its tributaries (Meaney 
2003; King 2006a; King 2006b; King et al. 2006b), and the Horseshoe 
Creek area (Krutzsch 1954, p. 453). While the western jumping mouse has 
also been confirmed from the Glendo Reservoir drainage, the Preble's 
meadow jumping mouse appears more common.
    In the Lower Laramie drainage, the Preble's meadow jumping mouse 
has been confirmed from the Laramie River and its tributaries, 
including the North Laramie River, and Sturgeon, Wyman,

[[Page 63001]]

Rabbit, and Luman Creeks; as well as several locations along Chugwater 
Creek and its tributaries (King 2006b; King et al. 2006b). Both 
Preble's meadow jumping mice and western jumping mice occur in the 
Sybille Creek, Friend Creek and the Friend Park areas (Conner and Shenk 
2003b; King 2006a; King 2006b; King et al. 2006b). The Lower Laramie 
drainage appears to support coexisting Preble's meadow jumping mice and 
western jumping mice in multiple locations.
    In the Horse Creek drainage, the Preble's meadow jumping mouse has 
been widely documented west of Interstate Highway 25 (I-25) and at one 
site east of I-25. The majority of these recent captures have been made 
in Bear Creek and its tributaries, and in headwaters of Horse Creek and 
its tributaries. Both Preble's meadow jumping mice and western jumping 
mice inhabit multiple sites on both creeks (Conner and Shenk 2003b; 
Meaney 2003; King 2006b; King et al. 2006b).
    In the Upper Laramie drainage, the Preble's meadow jumping mouse 
has been confirmed at Hutton Lake National Wildlife Refuge (NWR) and 
from a site north of Laramie (Meaney 2003). Other specimens at these 
same sites have been confirmed as western jumping mice (Meaney 2003; 
King 2006a). Therefore, it appears both Preble's meadow jumping mice 
and western jumping mice are present in this drainage. Based on 
positive identification of the Preble's meadow jumping mouse from the 
sites mentioned above, Smith et al. (2004, p. 12) suggested the range 
of the Preble's meadow jumping mouse may extend into the Upper Laramie 
River, Little Laramie River, Rock Creek, and possibly the Medicine Bow 
River.
    South Platte River Basin, Wyoming. Within the Wyoming portion of 
the South Platte River basin, trapping efforts have confirmed Preble's 
meadow jumping mouse occurrence, albeit possibly in low numbers, within 
two drainages in Laramie and Albany Counties.
    In the Upper Lodgepole drainage, jumping mice have been found from 
several locations at and upstream of Highway 211. While at least one 
Preble's meadow jumping mouse has been confirmed (Riggs et al. 1997), 
most of the captured mice have been identified as western jumping mice 
(Meaney 2003; King 2006a). Therefore, while this drainage supports the 
Preble's meadow jumping mouse, its distribution may be limited.
    Although historically reported from the Crow Creek drainage at 
Cheyenne, Preble's meadow jumping mouse occurrence in this drainage 
remains uncertain. Specimens from Warren Air Force Base were assumed to 
be Preble's meadow jumping mice based on the elevation of 1,900 m 
(6,150 ft), but subsequent analyses identified only western jumping 
mice (Riggs et al. 1997; Conner and Shenk 2003b; King 2006a). The only 
trapping evidence confirming Preble's meadow jumping mouse occurrence 
in this drainage comes from a specimen from the South Crow Creek 
Reservoir area originally identified as a western jumping mouse by the 
DMNS and then re-identified as a Preble's meadow jumping mouse based on 
a DFA analysis considering dental characteristics (Meaney 2003). 
Additional specimens have only verified western jumping mice from 
Middle Crow Creek, the South Fork of Middle Crow Creek, and South Crow 
Creek Reservoir (Meaney 2003; King 2006a). No jumping mice have been 
reported trapped downstream of Cheyenne.
    The Lone Tree Creek drainage was previously assumed to be inhabited 
by the Preble's meadow jumping mouse based on the field identification 
of low elevation captures of jumping mice (1,900 m (6,200 ft)). 
However, DFA analysis of existing museum specimens (Conner and Shenk 
2003b) and genetic analysis of specimens obtained from trapping efforts 
(Riggs et al. 1997; King 2006a), have only confirmed presence of 
western jumping mice in this drainage.
    South Platte River Basin, Colorado. Recent presence of the Preble's 
meadow jumping mouse in Colorado has been documented within the South 
Platte River basin in seven counties: Larimer, Weld, Boulder, 
Jefferson, Douglas, Elbert, and El Paso. From the Wyoming State line 
south through the Denver area, little recent documentation of the 
Preble's meadow jumping mouse exists from sites east of the foothills 
where most of the subspecies' historical recordings occurred. This area 
largely corresponds to the Front Range urban corridor, an area 
experiencing continued human population growth and development 
(Clippenger 2002, pp. 22-26; Colorado Demography Office 2007). At 
higher elevation plains and foothills sites south of the Denver area, 
the Preble's meadow jumping mouse has been documented at a number of 
locations where