62992 Federal Register / Vol. 72, No. 215 / Wednesday, November 7, 2007 / Proposed Rules 

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. 

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: http://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 

http://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 

http://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 http:// 

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 peerreviewed 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 basepairs, 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 


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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; OylerMcCance 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; OylerMcCance 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; OylerMcCance 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 11⁄2 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 11⁄2 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 


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(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; OylerMcCance 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 http:// 

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 


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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 


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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. 


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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 semiarid 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, 


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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 riparian habitats are 

still largely intact. With rare exception, 

all jumping mouse records verified 

below 2,050 m (6,700 ft) in the South 

Platte River drainage of Colorado have 

been Preble’s meadow jumping mice. 

In the Cache La Poudre River 

drainage, jumping mice have been 

documented on sites upstream of Fort 

Collins, Larimer County, at elevations 

consistent with known Preble’s meadow 

jumping mouse distribution. These sites 

include the main stem Cache La Poudre 

River and its tributaries, including 

Young Gulch and Stove Prairie Creek, 

and the North Fork Cache La Poudre 

River and its tributaries, including 

Stonewall, Rabbit, and Lone Pine 

Creeks. Shenk and Eussen (1999, pp. 

11–12) cautioned that both Preble’s 

meadow jumping mice and western 

jumping mice were likely present in 

some of these areas. Subsequent genetic 

analysis confirmed both Preble’s and the 

western jumping mouse in Cherokee 

Park at 2,260 m. (7,480 ft) (King 2005, 

2006b), but only Preble’s meadow 

jumping mice have been confirmed from 

lower elevations, including Rabbit and 

Lone Pine Creeks, the Livermore 

Mountain area, and the North Fork of 

the Cache La Poudre River (Riggs et al. 

1997; King et al. 2006b). Despite a 

number of trapping efforts, no jumping 

mice have been recently documented 

within the Fort Collins, Larimer County, 

area or downstream on the Cache La 

Poudre River to its confluence with the 

South Platte River at Greeley, Weld 

County (Service 2007). 

Within the Big Thompson drainage, 

the Preble’s meadow jumping mouse 

has been documented in foothills sites 

along Buckhorn Creek and certain of its 

tributaries, and on Dry Creek, in Larimer 

County. Genetic analysis of mice from 

three tributaries of Buckhorn Creek up 

to 2,240 m (7,360 ft) support 

identifications as Preble’s meadow 

jumping mice; however, both Preble’s 

meadow jumping mice and western 

jumping mice were confirmed from the 

Lakey Canyon site at 2,170 m (7,120 ft) 

and a mouse from the North Fork of the 

Big Thompson River at 2,170 m (7,120 

ft) was identified as a western jumping 

mouse (King 2006a). Despite a number 

of trapping efforts, the Preble’s meadow 

jumping mouse has not been 

documented on the Big Thompson and 

Little Thompson Rivers through the 

Front Range urban corridor, but has 

been found on both rivers east of I–25, 

in Weld County. 

In the Saint Vrain drainage, the 

Preble’s meadow jumping mouse has 

been documented along the Saint Vrain 

River, its tributaries and water 

conveyance ditches upstream of the 

town of Hygiene, on two tributaries of 

Boulder Creek west of the City of 

Boulder, and along South Boulder 

Creek, all in Boulder County; and on 

upper reaches of Coal and Rock Creeks, 

Jefferson County. On Rocky Flats NWR, 

Jefferson County, the Preble’s meadow 

jumping mouse has been documented 

on Rock Creek as well on nearby Walnut 


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and Woman Creeks (within the Middle 

South Platte-Cherry Creek drainage). 

Several of these locations include mice 

confirmed as Preble’s meadow jumping 

mice by genetic analysis or DFA (Riggs 

et al. 1997; Conner and Shenk 2003b). 

The Preble’s meadow jumping mouse 

occurrence has not been confirmed by 

trapping efforts along eastern parts of 

the drainage, the Saint Vrain River from 

Hygiene, Boulder County, downstream 

to its confluence with the South Platte 

River, along Boulder Creek from the City 

of Boulder east to its confluence with 

the Saint Vrain River, or downstream of 

Rocky Flats NWR on Walnut, Woman, 

or Dry Creeks. 

In the Clear Creek drainage, the 

Preble’s meadow jumping mouse has 

been verified in the foothills on Ralston 

Creek (Riggs et al. 1997), and 

unidentified jumping mice have been 

captured on two tributaries of Clear 

Creek at elevations of potential Preble’s 

meadow jumping mouse occurrence 

(below 2,300 m (7,600 ft)). No jumping 

mice have been captured on either creek 

downstream through the urban corridor 

to the South Platte River. 

In the Upper South Platte drainage, 

the Preble’s meadow jumping mouse 

has been documented immediately 

upstream of Chatfield Reservoir on the 

South Platte River, and also well 

upstream on the South Platte River and 

its tributaries in Jefferson and Douglas 

Counties to near the Teller CountyDouglas County line. The U.S. Forest 

Service provided a summary of Preble’s 

meadow jumping mouse trapping efforts 

at 15 sites in the Upper South Platte 

drainage in the Pike National Forest. 

Based on examination of voucher 

specimens, Preble’s meadow jumping 

mice were confirmed at six sites up to 

2,300 m (7,600 ft) and western jumping 

mice were confirmed from six sites, the 

lowest of which, at 2,030 m (6,660 ft), 

was lower than five Preble’s meadow 

jumping mouse sites (Bohon et al. 2005). 

Schorr et al. (2007) also summarized cooccurrence of Preble’s and the western 

jumping mouse in the same area. Also 

in the Upper South Platte drainage, the 

Preble’s meadow jumping mouse has 

been widely documented upstream of 

Chatfield Reservoir on Plum Creek, 

including occurrences on East Plum 

Creek, West Plum Creek, and various 

tributaries, all in Douglas County (Riggs 

et al. 1997; Conner and Shenk 2003b; 

King et al. 2006b). Western jumping 

mice have also been identified in this 

drainage at 1,800 m (5,900 ft) and 1,950 

m (6,400 ft) (Conner and Shenk 2003b). 

Pague and Schuerman (1998, p. 5) 

assessed Preble’s meadow jumping 

mouse habitat throughout the Plum 

Creek watershed, randomly trapped 

suitable habitat, and estimated 64 km 

(40 mi) of streams occupied by the 

Preble’s meadow jumping mouse. On 

the downstream portion of this 

drainage, below Chatfield Reservoir, 

there is no recent documentation of 

Preble’s meadow jumping mouse’s 

presence on the South Platte River 

through Denver. 

In the Middle South Platte, Cherry 

Creek drainage, Preble’s meadow 

jumping mice have been found on 

Cherry Creek and its tributaries from 

approximately the Arapahoe CountyDouglas County line, upstream to the 

headwaters of East and West Cherry 

Creeks near the Palmer Divide in El 

Paso County. Also within Middle South 

Platte-Cherry Creek drainage, limited 

trapping efforts have documented the 

Preble’s meadow jumping mouse on 

Running Creek and a tributary, Hay 

Creek, in Elbert County. Based on 

limited genetic analysis and DFA, 

western jumping mice have not been 

confirmed from this drainage. The 

Preble’s meadow jumping mouse 

occurrence has not been confirmed by 

trapping downstream along Cherry 

Creek through Arapahoe County and 

Denver to the South Platte River. 

Because of numerous negative trapping 

efforts and lack of contiguous suitable 

habitat, we no longer consider the 

greater Denver area (including most of 

Denver County and portions of Adams, 

Arapahoe, Boulder, Broomfield, 

Douglas, and Jefferson Counties) to be 

occupied. On the South Platte River 

downstream from the Denver area, a 

single Preble’s meadow jumping mouse 

was recently captured from near the 

South Platte River in Milliken, Weld 

County, not far from the confluence of 

the Big Thompson River and South 

Platte River (Savage and Savage 2001). 

Farther east, there are two records of 

a Preble’s meadow jumping mice on 

Kiowa Creek, Elbert County. Additional 

trapping in Elbert County would be 

useful to document whether the Preble’s 

meadow jumping mouse is present 

along significant reaches of the Middle 

South Platte-Cherry Creek and Kiowa 

Creek drainages, and on the Bijou Creek 

drainage, Elbert County, which has not 

been trapped. 

Arkansas River Basin, Colorado. In 

the Arkansas River basin, confirmed 

current occurrence of the Preble’s 

meadow jumping mouse is limited 

largely to the Fountain Creek drainage 

and specifically to Monument Creek and 

its tributaries north of Colorado Springs. 

Genetic analysis and DFA have thus far 

confirmed no western jumping mice 

from within the Preble’s meadow 

jumping mouse’s range in this drainage 

(Conner and Shenk 2003b; King et al. 

2006b). The Preble’s meadow jumping 

mouse has been well studied at the U.S. 

Air Force Academy (Academy) on 

Monument Creek and its tributaries, and 

has been documented farther upstream 

on Monument Creek and on tributaries 

to the east and north toward the Palmer 

Divide. Numerous records of Preble’s 

meadow jumping mouse captures on 

streams in northwestern El Paso County 

are the result of extensive trapping that 

has taken place in conjunction with 

proposed development projects. 

Downstream of the Academy, numerous 

trapping surveys indicate that the 

Preble’s meadow jumping mouse has 

little likelihood of occurrence along 

Monument Creek through the 

downtown portions of Colorado 

Springs. Similarly, extensive trapping 

surveys suggest that the Preble’s 

meadow jumping mouse may be 

extirpated from Cottonwood Creek and 

its tributaries. 

In the Chico Creek drainage, jumping 

mice (assumed to be Preble’s meadow 

jumping mice as explained above) have 

been documented on the upper reaches 

of Black Squirrel Creek and on a 

tributary, both in El Paso County. 

Limited trapping efforts in potential 

Preble’s meadow jumping mouse habitat 

farther to the east in the Chico Creek 

drainage and in the Big Sandy Creek 

drainage have not confirmed Preble’s 

meadow jumping mouse occurrence. 

Downstream, to the east and south, 

these drainages appear to have little 

habitat suitable for the Preble’s meadow 

jumping mouse. 

Within the Arkansas River basin 

south of the documented Preble’s 

meadow jumping mouse locations, 

trapping efforts targeting the Preble’s 

meadow jumping mouse conducted in 

southern El Paso County, Pueblo 

County, and Fremont County, including 

surveys funded and carried out by the 

Department of the Army at Fort Carson, 

have not resulted in capture of jumping 

mice (Bunn et al. 1995; Werner 2003). 

In conclusion, the Preble’s meadow 

jumping mouse appears to be 

widespread in the North Platte River 

basin were trapping efforts confirm the 

subspecies’ distribution across at least 

four drainages. The Preble’s meadow 

jumping mouse appears scarce within 

the Wyoming portion of the South Platte 

River basin, where trapping efforts to 

date provide few confirmed occurrences 

of the subspecies and suggest that the 

western jumping mouse is much more 

widespread. Trapping efforts within the 

Colorado portion of the South Platte 

River Basin indicate the Preble’s 

meadow jumping mouse has little 

likelihood of occurrence in portions of 

some drainages that coincide with the 


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Front Range development corridor 

(areas around I–25 from Fort Collins 

south through the Denver metropolitan 

area), is more widespread in foothills 

and some montane areas within these 

same drainages, and generally present in 

rural portions of drainages south of 

Denver. In the Arkansas River basin in 

Colorado, Preble’s meadow jumping 

mouse distribution appears very 

limited, with trapping efforts confirming 

occurrence largely in upper Monument 

Creek and some headwater tributaries. 

Data limitations, such as limited 

trapping data, do not allow us to equate 

documented distribution with range. 

For example, the subspecies has been 

documented in several places along Hay 

Creek in Elbert County, and it is 

reasonably likely to occur further 

downstream in Arapahoe County, but 

no trapping has occurred to confirm or 

deny this assertion (See figure 1). 

Similarly, on Trout Creek a Preble’s 

meadow jumping mouse was found in 

Douglas County near the Teller County 

line and it is reasonable to assume the 

subspecies may also occur in Teller 

County. Given the data limitations, 

‘‘range’’ (relative to the March 14, 2007, 

Department of the Interior, Solicitor 

Memorandum opinion) is defined in the 

Conclusion of the 5-Factor Analysis 

section of this rule below. 

Abundance 

Intensive trapping studies designed to 

estimate populations of the Preble’s 

meadow jumping mouse have occurred 

on only a few sites. Because not all 

appropriate habitat has been surveyed 

for Preble’s meadow jumping mouse 

occurrence and because population 

estimates are available for only a few 

selected sites, no regional, Statewide, or 

rangewide population estimates for the 

Preble’s meadow jumping mouse have 

been developed. Population density and 

trends are not well known in Wyoming 

(Wyoming Game and Fish Department 

2005, p. 36). There are a few population 

estimates but little trend information for 

Preble’s meadow jumping mouse 

populations in Colorado. In addition, 

because jumping mouse populations in 

a given area vary significantly from year 

to year (Quimby 1951, pp. 91–93; 

Whitaker 1972, p. 4), short-term studies 

may not accurately characterize 

abundance. In an ongoing trapping 

study, population highs of 24 Preble’s 

meadow jumping mice per site were 

estimated for two control sites in 1998 

and 1999; subsequent trapping in 2002, 

during regional drought conditions, 

estimated no Preble’s meadow jumping 

mice present at either site (Bakeman 

2006, p. 11). Meaney et al. (2003, p. 620) 

estimated Preble’s meadow jumping 

mouse populations on study sites over 

4 years, noted absence of the Preble’s 

meadow jumping mouse at certain sites 

during some seasons, and suggested that 

10 or more years of study might be 

necessary to assess the full extent of 

population variation. 

White and Shenk (2000, p. 9) 

summarized abundance estimates from 

nine sites in Colorado for field work 

conducted during 1998 and 1999 

(Meaney et al. 2000; Kaiser-Hill 2000; 

Ensight Technical Services 1999, 2000, 

2001; Shenk and Sivert 1999b; Schorr 

2001). Since Preble’s meadow jumping 

mice are found in linear riparian 

communities, abundances were 

estimated in number of individuals per 

km (or mi) of stream corridor. Estimates 

of linear abundance ranged widely, from 

4 to 67 mice/km (6 to 107 mice/mi) with 

a mean of 33 +/¥5 mice/km (53 +/¥8 

mice/mi) (White and Shenk 2000, p. 9). 

The subsequent addition of new sites 

and 2 more years of data (2000–2001) 

provided a range of 2 to 67 mice/km (3 

to 107 mice/mi) and a mean of 27 +/¥4 

mice/km (44 +/¥6 mice/mi) (Shenk 

2004). 

The above estimates, coupled with 

sufficient knowledge of occupied stream 

miles, can provide a rough indicator of 

Preble’s meadow jumping mouse 

numbers within a stream reach or 

drainage. For example, the Preble’s 

meadow jumping mouse Recovery Team 

used the above estimate (Shenk 2004) to 

approximate stream miles required to 

support varying sized populations of the 

Preble’s meadow jumping mouse 

(Service 2003b, p. 25). Hayward (2002) 

cautioned that reliance on an average 

number of mice per length of stream to 

predict population sizes would result in 

the overestimation of actual population 

size for about half of all sites. Of 

additional concern in any assessment of 

Preble’s meadow jumping mouse 

population size is the potential for 

including western jumping mice in the 

estimate (Bohon et al. 2005; Schorr et al. 

2007, p. 4). This is of particular 

importance in areas where both Preble’s 

meadow jumping mice and western 

jumping mice are known to occur, 

including higher elevation Colorado 

sites and at most sites in Wyoming. 

Another potential source of error is 

that the Preble’s meadow jumping 

mouse population estimates above do 

not include estimates for riparian 

corridors along mountain streams or any 

sites in Wyoming. In Pike National 

Forest, Colorado, site inspection of 

many streams previously mapped as 

Preble’s meadow jumping mouse habitat 

revealed poorly developed or 

intermittent riparian vegetation 

surrounded by sparse uplands 

dominated by pine forest (Bohon et al. 

2005). Poor trapping success even in 

suitable habitat suggested low 

population densities in Pike National 

Forest compared to those at lower 

elevations (Bohon et al. 2005; Hansen 

2006, p. 168). In studies targeting the 

Preble’s meadow jumping mouse at 11 

higher elevations (1,890 to 2,420 m 

(6,200 to 7,940 ft)) riparian sites in 

Douglas, Jefferson, and Teller Counties, 

Schorr et al. (2007, p. 4) reported a 0.6 

percent capture rate of jumping mice 

over 19,500 trap nights. Since 

coexistence of both the Preble’s meadow 

jumping mouse and the western 

jumping mouse was confirmed in these 

studies, the capture rate of the Preble’s 

meadow jumping mouse was probably 

much lower. In comparable trapping 

effort in high quality habitat at lower 

elevations, Schorr (2001, p.18) reported 

a 3.5 percent capture rate of Preble’s 

meadow jumping mice over 14,700 trap 

nights at the Academy, and Meaney et 

al. (2003, p. 616) reported a 3.4 percent 

capture rate of Preble’s meadow 

jumping mice over 21,174 trap nights 

along South Boulder Creek, Boulder 

County. We believe that more research 

is needed before conclusions can be 

drawn regarding Preble’s meadow 

jumping mouse abundance and security 

along montane streams and headwaters. 

Trends 

Without comprehensive population 

estimates for the subspecies, the only 

basis for trend assessment is presence or 

absence surveys in historical habitat 

(Smith et al. 2004, p. 29). This presence/ 

absence information paints a very 

different picture for Wyoming compared 

to Colorado. 

In Wyoming, we now have much 

more information regarding Preble’s 

meadow jumping mouse distribution 

than we had at time of listing, when we 

described only two occupied sites. 

Much of what we noted in the listing to 

be historical range of the Preble’s 

meadow jumping mouse in Wyoming 

has now been definitively found to 

support Preble’s. But, while many 

jumping mice have been confirmed as 

Preble’s meadow jumping mice in the 

North Platte River basin, the subspecies 

appears uncommon in the South Platte 

River basin, with only western jumping 

mice previously confirmed at several 

locations believed to be within Preble’s 

meadow jumping mouse range. 

In Colorado, historical trapping 

records establish that the Preble’s 

meadow jumping mouse was present in 

a range that included major plains 

streams from the base of the Colorado 

Front Range east to at least Greeley, 

Weld County (Armstrong 1972, p. 249; 


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Fitzgerald et al. 1994, p. 293, Clippenger 

2002, p. 18). Recent trapping efforts 

have documented that the Preble’s 

meadow jumping mouse is rare or, 

perhaps, absent from these same areas 

today (Ryon 1996, p. 2; Clippinger 2002, 

p. 22; Service, 2007). This pattern is 

especially apparent along prairie 

riparian corridors directly or indirectly 

impacted by human development. This 

issue is discussed further in Factor A 

below. 

Summary of Factors Affecting the 

Subspecies 

Section 4 of the Act and its 

implementing regulations (50 CFR part 

424) set forth the procedures for listing, 

reclassifying, or removing species from 

listed status. ‘‘Species’’ is defined by the 

Act as including any species or 

subspecies of fish or wildlife or plants, 

and any distinct vertebrate population 

segment of fish or wildlife that 

interbreeds when mature (16 U.S.C. 

1532(16)). Once the ‘‘species’’ is 

determined we then evaluate whether 

that species may be endangered or 

threatened because of one or more of the 

five factors described in section 4(a)(1) 

of the Act. We must consider these same 

five factors in delisting determinations. 

Under 50 CFR 424.11(d), we may 

remove the protections of the Act if the 

best available scientific and commercial 

data substantiate that the species is 

neither endangered nor threatened for 

the following reasons: (1) the species is 

extinct; (2) the species has recovered 

and is no longer endangered or 

threatened; or (3) the original scientific 

data used at the time the species was 

classified were in error. Data error only 

applies when subsequent investigations 

show that the best scientific or 

commercial data available when the 

species was listed, or the interpretation 

of such data, were in error. 

We may delist a species for any of the 

above reasons only if such data 

substantiate that the species is neither 

endangered nor threatened. Determining 

whether a species meets these 

definitions requires consideration of the 

same five categories of threats specified 

in section 4(a)(1) of the Act. For species 

that are already listed as endangered or 

threatened, this analysis of threats is an 

evaluation of both the threats currently 

facing the species and the threats that 

are reasonably likely to affect the 

species in the foreseeable future 

following the delisting or downlisting 

and the removal or reduction of the 

Act’s protections. 

Under section 3 of the Act, a species 

is ‘‘endangered’’ if it is in danger of 

extinction throughout all or a 

‘‘significant portion of its range’’ and is 

‘‘threatened’’ if it is likely to become 

endangered within the foreseeable 

future throughout all or a ‘‘significant 

portion of its range.’’ The word ‘‘range’’

in the phrase ‘‘significant portion of its 

range’’ refers to the range in which the 

species currently exists. Range is 

discussed further in the Conclusion of 

the 5-Factor Analysis section of this 

proposal below. 

For the purposes of this analysis, we 

will evaluate whether the currently 

listed subspecies is threatened or 

endangered. This determination is a 

multiple-step analysis. If we determine 

that the subspecies is endangered 

throughout all of its range, we list it as 

endangered throughout its range and no 

further analysis is necessary. If not, we 

then evaluate if the subspecies meets 

the definition of threatened throughout 

all of its range. If the subspecies is 

threatened in all of its range, we list as 

threatened and consider if any 

significant portions of the range 

warrants consideration as endangered. If 

we determine that the subspecies is not 

threatened or endangered in all of its 

range, we consider whether any 

significant portions of the subspecies’

range warrant consideration as 

threatened or endangered. We would 

then only list that significant portion of 

its range as threatened or endangered 

and not list the remaining portion of its 

range. 

Foreseeable future is determined by 

the Service on a case-by-case basis, 

taking into account a variety of speciesspecific factors such as lifespan, 

genetics, breeding behavior, 

demography, threat-projection 

timeframes, and environmental 

variability. For the purposes of this 

proposal, we define foreseeable future 

based upon a threat-projection 

timeframe because future development 

intensity and patterns are likely to be 

the single greatest factor contributing to 

the subspecies’ future conservation 

status. As described in more detail 

below, human-population-growth 

projections extend out to 2035 in 

Colorado and 2036 in Wyoming. 

Similarly, water requirements are 

estimated through 2030 in Colorado and 

2035 in Wyoming. A Center for the West 

model predicting future land-use 

patterns projects development changes 

within the range of Preble’s through 

2040. Such projections frame our 

analysis as they help us understand 

what factors can reasonably be 

anticipated to meaningfully affect the 

subspecies’ future conservation status. 

In our view, the foreseeable future for 

this subspecies, based on the currently 

available data, does not extend beyond 

2040. While it is likely some of the 

above estimates could be extrapolated 

out into the more distant future, 

development projections beyond this 

point are of increasingly lower value as 

uncertainty escalates. 

The following analysis examines all 

five factors currently affecting, or that 

are likely to affect, the Preble’s meadow 

jumping mouse within the foreseeable 

future. 

A. The Present or Threatened 

Destruction, Modification, or 

Curtailment of Its Habitat or Range 

Introduction. Decline in the extent 

and quality of Preble’s meadow jumping 

mouse habitat has been considered the 

primary factor threatening the 

subspecies (Bakeman 1997, p. 78; 

Hafner et al. 1998, p. 122; Pague and 

Grunau 2000). In our 1998 final rule to 

list Preble’s meadow jumping mouse as 

threatened (63 FR 26517, May 13, 1998), 

we stated that Colorado east of the Front 

Range and adjacent areas of 

southeastern Wyoming had changed, 

over time, from predominantly prairie 

habitat intermixed with perennial and 

intermittent streams and associated 

riparian habitats to an agricultural and 

increasingly urban setting. 

In our listing decision, we stated that 

Preble’s meadow jumping mouse 

populations had experienced a decline 

and faced continued threats linked to 

widespread loss and fragmentation of 

the subspecies’ required riparian habitat 

from human land uses including: urban, 

suburban, and recreational 

development; highway and bridge 

construction; water development; 

instream changes associated with 

increased runoff and flood control 

efforts; aggregate (sand and gravel) 

mining; and overgrazing (63 FR 26517, 

May 13, 1998). These human land-use 

activities affect the Preble’s meadow 

jumping mouse by directly destroying 

its protective cover, nests, food 

resources, and hibernation sites; 

disrupting behavior; or acting as a 

barrier to movement. We noted that 

such impacts reduced, altered, 

fragmented, and isolated habitat to the 

point where Preble’s meadow jumping 

mouse populations may no longer 

persist. We also noted that patterns of 

capture suggested that Preble’s meadow 

jumping mouse populations fluctuate 

greatly over time at occupied sites, 

raising questions regarding security of 

the many currently documented 

populations which are isolated and 

affected by human development. 

Historical records in Colorado (pre1980) illustrate areas of Preble’s 

meadow jumping mouse occupancy 

along the Front Range within both 

foothill and prairie riparian corridors 


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(Armstrong 1972, p. 249; Fitzgerald et 

al. 1994, p. 293). Between 1980 and 

2005, the human population of Colorado 

counties within the Preble’s meadow 

jumping mouse range increased by 

nearly 60 percent, from 1.7 million to 

2.7 million (Colorado Demography 

Office, 2007). As explained further 

below, the apparent absence of the 

Preble’s meadow jumping mouse in 

areas of substantial development, where 

trapping had previously confirmed 

subspecies presence, supports the 

conclusion that human land uses 

adversely affect Preble’s meadow 

jumping mouse populations. 

Ryon (1996) evaluated the condition 

of eight historical Preble’s meadow 

jumping mouse capture sites in six 

Colorado counties based on vegetation 

structure, dominant plant species, and 

trapping results. Ryon reported no 

Preble’s meadow jumping mouse 

captures at any of the seven sites 

trapped (one site no longer contained 

suitable habitat) (1996, p. 25). In 

addition, he reported that the historical 

sites contained fewer native species in 

plant communities and were lacking the 

multi-strata vegetation structure he 

observed at sites where trapping had 

recently confirmed Preble’s meadow 

jumping mouse presence (Ryon 1996, p. 

30). Investigations into land-use changes 

at the historical sites suggested that 

most had been directly altered in terms 

of habitat or had been influenced by 

habitat fragmentation (Ryon, 1996, p. 

30). Clippinger (2002, pp. 14–29) 

mapped and compared past (through 

1972) and current (post-1972) 

distribution records of the Preble’s 

meadow jumping mouse in central 

Colorado and southeastern Wyoming 

based on museum specimens, published 

accounts, and unpublished reports. 

Clippinger reported that his distribution 

maps illustrated a loss of Preble’s 

populations in expanding urban and 

suburban areas, especially around 

Cheyenne, Denver, and Colorado 

Springs, and in general along the eastern 

extent of historical range (Clippinger 

2002, p. 22). Note that Clippinger’s 

reference to historical range is based on 

the few existing records (through 1972) 

documenting Preble’s meadow jumping 

mouse occurrence. These records are 

focused around what is now the I–25 

urban corridor and based upon our 

current knowledge of the subspecies do 

not truly represent the extent of the 

range of the subspecies. The apparent 

loss of historically occupied sites (those 

sites where the subspecies was 

documented to occur prior to 1980) also 

provides some insight into this 

relationship. Based on Service records, 

consisting of intensive trapping efforts 

and assessments of habitat quality, only 

1 of 17 of these documented historical 

sites of Preble’s meadow jumping mouse 

occurrence in Colorado (Bear Creek, 

Boulder County) is thought to currently 

support the Preble’s meadow jumping 

mouse. 

Recent trapping records maintained 

by the Service indicate that Preble’s 

meadow jumping mouse populations 

have little likelihood of occurrence 

along large portions of major river and 

stream reaches within the subspecies’

historical described range in Colorado 

including: 

• The Cache La Poudre River within 

Fort Collins and downstream to its 

confluence with the South Platte River 

at Greeley, 60 km (37 mi); 

• The Big Thompson River and Little 

Thompson River through the Front 

Range urban corridor, approximately 50 

km (32 mi); 

• The Saint Vrain River from Hygiene 

to its confluence with the South Platte 

River, 35 km (22 mi); 

• Boulder Creek from Boulder east to 

its confluence with the Saint Vrain 

River, approximately 35 km (22 mi); 

• Walnut, Woman, and Dry Creeks 

downstream from Rocky Flats National 

Wildlife Refuge (NWR) to the 

confluence of Dry Creek and beyond to 

the South Platte River, 40 km (25 mi); 

• Ralston Creek and Clear Creek 

through the urban corridor to the South 

Platte River, approximately 40 km (25 

mi); 

• The South Platte River downstream 

of Chatfield Reservoir through Denver to 

Brighton, 60 km (38 mi); 

• The South Platte River downstream 

from Brighton to Greeley, approximately 

55 km (34 mi) (one recent Preble’s 

capture); 

• Cherry Creek from the Arapahoe 

County-Douglas County line 

downstream through Denver to the 

South Platte River, 30 km (19 mi); 

• Monument Creek downstream from 

its confluence with Cottonwood Creek 

through Colorado Springs, 

approximately 15 km (9 mi). 

In total, Preble’s meadow jumping 

mouse populations appear to have little 

likelihood of occurrence along 420 km 

(260 mi) in and downstream of areas 

with concentrated human development. 

However, despite apparent local 

extirpations, many of these streams 

continue to support Preble’s meadow 

jumping mouse populations in their 

upstream reaches or tributaries. 

Historical losses relative to ongoing 

threats are relevant in predicting 

whether the subspecies is likely to 

become endangered in all or a 

significant portion of its current range 

within the foreseeable future. It appears 

unlikely that the Preble’s meadow 

jumping mouse can be returned to the 

historical localities within the Front 

Range urban corridor; however, we find 

that the subspecies’ apparent local 

extirpation from areas of human 

development provides useful 

perspective about the potential impacts 

of future development within the 

remaining range of the Preble’s meadow 

jumping mouse. If the protections of the 

Act are removed, we expect these threat 

factors, discussed in more detail below, 

would continue to affect the subspecies 

in large portions of its current range into 

the foreseeable future. 

For the purposes of this revised 

proposed rule, we reviewed and 

considered the best available 

information regarding threats within the 

range of the Preble’s meadow jumping 

mouse, including Ryon (1996), Shenk 

(1998), Bakeman (1997), Pague and 

Granau (2000), Clippinger (2002), and 

Service (2003b). We summarize these 

accounts below. 

Following listing, The Nature 

Conservancy, under a contract with the 

Colorado Division of Natural Resources, 

formed a Preble’s Meadow Jumping 

Mouse Science Team (Pague 1998). 

With guidance from the Science Team 

and following numerous meetings with 

scientists and stakeholders, Pague and 

Grunau (2000) developed a conservation 

planning handbook that addressed each 

of seven Colorado counties containing 

Preble’s meadow jumping mouse 

populations. The document provided 

‘‘issues and stresses’’ for all presumed 

threat factors operating in known or 

suspected Preble’s meadow jumping 

mouse habitat, and assigned a 

qualitative risk assessment level to each 

of the identified issues. The work of 

Pague and Granau (2000) continues to 

provide important, science-based 

insight into threats to, and potential 

conservation strategies for, the Preble’s 

meadow jumping mouse in Colorado on 

a county-by-county basis. Habitatrelated ‘‘issues’’ identified as high or 

very high priority in one or more 

counties included habitat conversion 

through housing, commercial, and 

industrial construction; travel corridor 

(i.e., roadway) construction; travel 

corridor maintenance; fragmentation of 

habitat and corridors; hydrological flow 

impairment; habitat conversion to a 

reservoir; bank stabilization; high 

impact livestock management; rock and 

sand extraction; invasive weeds; and 

catastrophic fire (Pague and Granau 

2000, pp. 1–15, 2–12, 3–13, 4–14, 5–14, 

6–15, 7–14). Pague (2007) provided 

observations updating the 2000 report. 

No comparable document exists for the 


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four Wyoming counties where the 

subspecies occurs. 

Colorado’s Comprehensive Wildlife 

Conservation Strategy lists the meadow 

jumping mouse (including both the 

Preble’s meadow jumping mouse and 

Zapus hudsonius luteus which occurs 

in extreme south-central Colorado) as a 

‘‘Species of Greatest Conservation 

Need,’’ citing threats to habitat and 

range including habitat conversion (due 

to housing, urban, and exurban 

development) and habitat degradation 

(due to altered native vegetation and 

altered hydrological regime) (CDOW 

2006, p. 102). 

The Wyoming Comprehensive 

Wildlife Plan (WCWP) also lists 

meadow jumping mouse (including both 

the Preble’s meadow jumping mouse 

and Zapus hudsonius campestris which 

occurs in northeastern Wyoming) as a 

‘‘Species of Greatest Conservation 

Need.’’ This plan identifies ecoregions 

in the State and provides a summary of 

‘‘mean habitat quality’’ scores for each 

ecological system (or habitat) within the 

ecoregion (WGFD 2005, pp. 19–25). 

Within the three Wyoming ecoregions 

that include Preble’s meadow jumping 

mouse range (Central Shortgrass Prairie, 

Northern Great Plains Steppe, and 

Southern Rocky Mountains), the two 

ecological systems most likely to 

support the Preble’s meadow jumping 

mouse (Rocky Mountain Lower 

Montane Foothill Riparian and 

Shrubland, Western Great Plains 

Riparian/Western Great Plains 

Floodplain) ranked in the lowest 20 

percent in mean habitat quality relative 

to the State’s other ecosystems (WGFD 

2005, pp. 19–25). Among threats to 

habitat in these ecoregions are invasive 

plants, residential development 

radiating from the Cheyenne area, and 

recreation in the Southern Rocky 

Mountain region (WGFD 2005, pp. 53, 

55, 56). 

The direct impacts of development on 

the Preble’s meadow jumping mouse 

and its habitat have likely slowed since 

our 1998 listing because of protection 

afforded to the Preble’s meadow 

jumping mouse and its critical habitat 

rangewide under the Act. One 

indication of continuing impacts to the 

Preble’s meadow jumping mouse and its 

habitat is the number of formal 

consultations performed to date under 

section 7 of the Act and the number of 

section 10 permits issued to date in 

conjunction with approved Habitat 

Conservation Plans (HCPs). Section 7 of 

the Act requires Federal agencies to 

consult with the Service to ensure that 

their actions do not jeopardize the 

continued existence of the subspecies or 

cause destruction or an adverse 

modification of critical habitat. Thus far, 

the section 7 process has been 

successful in avoiding adverse effects, 

from Federal actions, that would be 

likely to jeopardize the continued 

existence of the species or result in the 

destruction or adverse modification of 

critical habitat. 

Section 10(a)(1)(B) of the Act 

authorizes the Service to issue permits 

for non-Federal actions that result in the 

incidental taking of listed wildlife. 

Incidental take permit applications must 

be supported by an HCP that identifies 

conservation measures that the 

permittee agrees to implement for the 

species to avoid, minimize, and mitigate 

the impacts of the requested incidental 

take. 

As of August 2007, we have 

conducted 124 formal section 7 

consultations (109 in Colorado, 15 in 

Wyoming) and issued 19 HCP related 

incidental take permits (all in Colorado) 

for projects affecting the Preble’s 

meadow jumping mouse. We have 

authorized take for actions that did not 

result in jeopardy but nevertheless 

resulted in permanent impacts to over 

320 hectares (ha) (800 acres (ac)) of 

Preble’s meadow jumping mouse 

habitat, and temporary impacts to more 

than twice that amount of land. These 

projects have incorporated conservation 

measures or mitigation to avoid or 

minimize adverse impacts to the 

Preble’s meadow jumping mouse. 

However, even with the protections 

afforded to the species under section 7, 

habitat overall has continued to decline 

in quality and quantity, especially in 

Colorado. In the absence of listing, 

projects in Preble’s meadow jumping 

mouse habitat would otherwise go 

forward with little Federal oversight. 

Other Federal, as well as State and local 

regulatory mechanisms, that may 

provide protection for the Preble’s 

meadow jumping mouse and its habitat 

are evaluated under Factor D below. 

Residential and Commercial 

Development. Clippinger (2002) 

assessed the impacts of residential 

development on the Preble’s meadow 

jumping mouse. He analyzed Colorado 

land-cover data compared to positive 

and negative trapping results for the 

Preble’s meadow jumping mouse in a 

geographic information system analysis 

and concluded that the likelihood of 

successful trapping of Preble’s meadow 

jumping mice was reduced by either 

low-or high-density residential 

developments when the developments 

were within 210 m (690 ft) of the 

trapping sites (Clippinger 2002, pp. iv, 

94). Clippinger (2002, p. iv) noted that 

the Preble’s meadow jumping mouse 

can be a useful indicator of 

environmental integrity in riparian areas 

and associated upland areas in the 

Colorado Piedmont. These data 

demonstrate that nearby development 

increases the risk of extirpation of 

Preble’s meadow jumping mice from 

occupied sites. 

Theobold et al. (1997) emphasized 

both housing density and spatial 

patterns in evaluating effects of 

residential development on wildlife 

habitat. They concluded that while 

clustered development can decrease 

habitat disturbance (Theobold et al. 

1997, p. 34), much of the Rocky 

Mountain West is experiencing what 

has been termed ‘‘rural sprawl’’ where 

rural areas are growing at a faster rate 

than urban areas (Theobold et al. 2001, 

p. 4). In Colorado, residential demand 

and State law encourage developers to 

design subdivisions with lots of at least 

14 ha (35 ac) each with one house, to 

avoid detailed county subdivision 

regulations (Riebsame et al., p. 420). The 

Larimer County Master Plan (Larimer 

County Planning Division 1997) cites a 

trend toward residential properties with 

relatively large lots, which leads to 

scattered development and more 

agricultural land taken out of 

production. Where public and private 

lands are intermingled, private land 

ownership typically follows valley 

bottoms (Theobald et al. 2001, p. 5), 

thus rural development is likely to 

disproportionately affect valley-bottom 

riparian areas (Riebsame et al., p. 402), 

the favored habitat of the Preble’s 

meadow jumping mouse. Beyond direct 

impact to habitat, when ranches are 

subdivided, subsequent residential 

construction and associated disturbance 

can result in the disruption of wildlife 

movement along stream corridors 

(Riebsame et al., p. 402). Rural 

development disproportionately occurs 

around edges of undisturbed public 

lands and affects the conservation value 

of the undisturbed public lands (Hansen 

et al. 2005, p. 1900). 

Human development often causes 

subtle effects on riparian habitat as well. 

Indirect effects of human settlement 

have resulted in declines in native trees 

and shrubs, greater canopy closure, and 

a more open understory with reduced 

ground cover within riparian habitat 

(Miller et al. 2003, p. 1055). An open 

understory does not favor the Preble’s 

meadow jumping mouse, which prefers 

dense ground cover of grasses and 

shrubs and is less likely to use open 

areas where predation risks are assumed 

to be higher (Trainor et al. 2007, pp. 

472–476; Clippinger 2002, pp. 69, 72). 

Fragmentation is another indirect 

impact of development in proximity to 

Preble’s meadow jumping mouse 


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habitat. The Preble’s meadow jumping 

mouse is closely associated with narrow 

riparian systems that represent a small 

percentage of the landscape within the 

subspecies’ range. Fragmentation of 

these linear habitats limits the extent 

and size of Preble’s meadow jumping 

mouse populations. As populations 

become fragmented and isolated, it 

becomes more difficult for them to 

persist (Caughley and Gunn 1996, pp. 

165–189). Major risks associated with 

small populations include—

demographic stochasticity (an increased 

risk of decline in small populations due 

to variability in population growth rates 

arising from random differences among 

individuals in survival and 

reproduction within a season); 

environmental stochasticity (an 

increased risk of decline in small 

populations due to variation in birth 

and death rates from one season to the 

next in response to weather, disease, 

competition, predation, or other factors 

external to the population); and loss of 

genetic variation (a reduction in the 

amount of diversity retained within 

populations and an increased chance 

that deleterious recessive alleles may be 

expressed; the loss of diversity can limit 

a population’s ability to respond 

adaptively to future environmental 

changes) (Caughley and Gunn 1996, pp. 

165–189). These issues are discussed in 

greater detail in Factor E below. The 

Recovery Team determined that small, 

fragmented units of habitat will not be 

as successful in supporting the Preble’s 

meadow jumping mouse in the long 

term as larger areas of habitat (Service 

2003b, p. 21). On a landscape scale, 

maintenance of dispersal corridors 

linking patches of Preble’s meadow 

jumping mouse habitat may be critical 

to the subspecies’ conservation (Shenk 

1998, p. 21). 

One indicator of the level of 

development pressure since listing is 

the number of development-related 

section 7 consultations and HCPs 

completed by the Service. Of the 109 

formal consultations and 19 HCPs 

completed in Colorado, 17 section 7 

consultations and 10 HCPs were 

specifically for residential and 

commercial developments with direct 

adverse effects to the Preble’s meadow 

jumping mouse or its habitat. Approved 

projects allowed for adverse impacts 

(permanent or temporary) in excess of 

180 ha (450 ac) of Preble’s habitat. 

While conservation measures or 

mitigation in various forms have been 

incorporated into all permitted projects, 

implementation of these habitat 

restoration and enhancement measures 

has been limited by factors such as 

droughts or floods. Recent development 

pressure has been most concentrated 

south of Denver, Colorado, in Douglas 

and El Paso Counties; eight section 7 

consultations and three HCPs have 

occurred in the Middle South PlatteCherry Creek drainage, all south of 

Denver, and six section 7 consultations 

and four HCPs have occurred in the 

Fountain Creek drainage. We have also 

worked with other Federal agencies and 

a substantial number of landowners and 

developers to avoid adverse impacts to 

Preble’s meadow jumping mouse 

habitat, thus avoiding formal 

consultation. Additional planned 

residential and commercial 

development projects that would 

adversely affect Preble’s meadow 

jumping mouse habitat in Colorado are 

continually being reviewed by the 

Service. Since listing, protections 

afforded under the Act have slowed, but 

not eliminated, the loss of Preble’s 

meadow jumping mouse habitat due to 

residential and commercial 

development in Colorado. We believe 

that in the absence of the protections 

under the Act, Preble’s meadow 

jumping mouse habitat in Colorado and 

the populations it supports would be 

lost at a greatly increased rate. 

Continued rapid development is 

expected along Colorado’s Front Range 

as the human population continues to 

grow. The State of Colorado expects the 

population of counties supporting the 

Preble’s meadow jumping mouse to 

increase by an additional 1.5 million 

people by 2035, including: 99,000 in 

Boulder County; 272,000 in Douglas 

County; 42,000 in Elbert County; 

369,000 in El Paso County; 143,000 in 

Jefferson County; 201,000 in Larimer 

County; and 323,000 in Weld County 

(Colorado Demography Office 2007). 

These expected increases support Pague 

and Grunau’s (2000) conclusion that 

habitat conversion is a very high 

priority issue to the Preble’s meadow 

jumping mouse in Larimer, Weld, and 

El Paso Counties, and a high priority 

issue for the remaining counties 

supporting the Preble’s meadow 

jumping mouse in Colorado. 

In contrast to the situation in 

Colorado, no formal section 7 

consultations or HCPs have been sought 

for residential or commercial 

development in Wyoming. This reduced 

level of consultations reflects the 

general lack of development pressure 

within Preble’s meadow jumping mouse 

habitat. This lack of development 

pressure is predicted to continue into 

the foreseeable future as described 

below. 

Wyoming estimates that the 

population of the counties supporting 

the Preble’s meadow jumping mouse 

will increase by about 11,000 people 

from 2005 to 2020, including: an 

increase of 800 in Albany County; an 

increase of 1,500 in Converse County; 

an increase of 9,100 in Laramie County; 

and a decrease of 400 in Platte County 

(Wyoming Department of 

Administration and Information 2007). 

Commercially available estimates 

suggest counties supporting the Preble’s 

meadow jumping mouse will increase 

by about 18,400 people from 2006 

through 2036, including: a decline of 

3,700 in Albany County; an increase of 

3,500 in Converse County; an increase 

of 18,300 in Laramie County; and an 

increase of 300 in Platte County 

(Economy.com 2007 as provided by Lui 

2007). 

While population growth rates 

provide valuable insight into 

development pressures, they may not 

provide a complete picture. For 

example, human population increases 

in Cheyenne, Fort Collins, Greeley, 

Longmont, the immediate Denver 

metropolitan area, and much of 

Colorado Springs are likely to have little 

direct impact on the Preble’s meadow 

jumping mouse because the subspecies 

appears to have little likelihood of 

occurrence within and downstream 

from these cities. Conversely, 

substantial human population increases 

in the Laramie Foothills of Larimer 

County, Colorado, or southern portions 

of Douglas County, Colorado, are likely 

to have a high impact to the Preble’s 

meadow jumping mouse. In Wyoming, 

given the small projected increases in 

the human population, we expect rural 

development will continue to have only 

small, localized impacts. 

Modeling exercises can also provide 

some insights into future land-use 

development patterns. While these 

models have weaknesses, such as an 

inability to accurately predict economic 

upturns or downturns, uncertainty 

regarding investments in infrastructure 

that might drive development (such as 

roads, airports, or water projects), and 

an inability to predict open-space 

acquisitions, we nevertheless believe 

such models are useful in adding to our 

understanding of likely patterns. For 

example in 2005, Center for the West 

produced a series of maps predicting 

growth through 2040 for the west 

including the Colorado Front Range and 

Wyoming (Travis et al. 2005, pp. 2–7). 

The projections for the Colorado Front 

Range (available at: http:// 

www.centerwest.org/futures/frtrng/ 

2040.html) illustrate significant 

increases in urban/suburban, lowdensity suburban, and exurban land 

uses across virtually all private lands 


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within the Colorado portion of the 

Preble’s meadow jumping mouse range. 

Only small isolated patches of Preble’s 

meadow jumping mouse habitat in 

public ownership, including headwater 

areas in Federal ownership, would 

avoid the direct impacts of residential 

and associated commercial 

development. Although similar maps for 

Wyoming are less refined (available at: 

http://www.centerwest.org/futures/west/ 

2040.html), they suggest only limited 

increases in development, primarily 

around Cheyenne. 

Based upon known impacts to the 

Preble’s meadow jumping mouse 

associated with development and best 

available projections for future 

development (as described above and in 

Factor D below), we conclude that 

residential and commercial 

development constitutes a substantial 

threat to the Preble’s meadow jumping 

mouse in Colorado, now and into the 

foreseeable future. In Wyoming, 

residential and commercial 

development is likely to be limited with 

only small, localized impacts to the 

Preble’s meadow jumping mouse 

expected. While some development is 

projected in the vicinity of Cheyenne, 

trapping efforts to date have not 

confirmed presence of Preble’s meadow 

jumping mice in this area. 

Transportation, Recreation, and Other 

Rights of Way Through Habitat. At the 

time of listing, the Service concluded 

that roads, trails, or other linear 

development through the Preble’s 

meadow jumping mouse’s riparian 

habitat could act as partial or complete 

barriers to dispersal (63 FR 26517, May 

13, 1998). These forms of development 

have continued to affect and fragment 

Preble’s meadow jumping mouse 

habitat. Since listing, the Service has 

conducted 38 formal consultations 

under section 7 of the Act for road or 

bridge projects (32 in Colorado and 6 in 

Wyoming) resulting in permitted 

impacts to approximately 50 ha (125 ac) 

of Preble’s meadow jumping mouse 

habitat. In addition, a formal 2005 

programmatic section 7 consultation 

with the Federal Highway 

Administration for the Wyoming 

Statewide Transportation Improvement 

Program could result in 19 future 

highway projects with impacts to 42 ha 

(104 ac) of Preble’s meadow jumping 

mouse habitat (Service 2005). Under the 

Douglas County (Colorado) Regional 

HCP for the Preble’s meadow jumping 

mouse, completed in May 2006, 67 

approved road and bridge construction 

projects by Douglas County, and the 

cities of Parker and Castle Rock, may 

affect up to 122 ha (302 ac) of Preble’s 

meadow jumping mouse habitat over a 

10-year period (Service 2006). 

One of the largest road projects is a 

proposed improvement to I–25 in El 

Paso County, Colorado. The proposed 

construction would affect 10 of the 11 

to 14 eastern tributaries of Monument 

Creek thought to support Preble’s 

(Bakeman and Meaney 2001, p. 21). 

Impacts to Preble’s would include 

habitat fragmentation and modification, 

change in population size, and 

behavioral impacts (Bakeman and 

Meaney 2001, pp. 18–20). While 

measures to avoid, minimize, and 

mitigate impacts were identified, the 

project would have significant 

cumulative effects on Preble’s meadow 

jumping mice in the Monument Creek 

drainage, especially east of I–25 

(Bakeman and Meaney 2001, pp. i, ii, 

22–27). 

With an increased human population, 

a high level of road construction and 

maintenance projects will occur; in the 

absence of the Act’s protective 

measures, impacts to Preble’s and its 

habitat would likely be substantial. 

While the Act rarely stops such projects, 

it does promote measures to avoid, 

minimize, or compensate for impacts 

and helps control the level of negative 

impacts to the Preble’s meadow jumping 

mouse and its habitat. Pague and 

Grunau (2000) considered ‘‘travel 

corridor construction’’ to be a high 

priority issue to Preble’s meadow 

jumping mouse populations in Weld, 

Douglas, Elbert, and El Paso Counties in 

Colorado. 

Human-caused impacts associated 

with recreation include backcountry 

roads, trails, and campgrounds, which 

are often located along streams and near 

water (Wyoming Game and Fish 

Department 2005, p. 56). Recreational 

trail systems are frequently located 

within riparian corridors (Meaney et al. 

2002, p. 116). The development of trail 

systems can affect the Preble’s meadow 

jumping mouse by modifying its habitat, 

nesting sites, and food resources in both 

riparian and upland areas. Use of these 

trails by humans or pets can alter 

wildlife activity and feeding patterns 

(Theobold et al. 1997, p. 26). Meaney et 

al. (2002, pp. 131–132) suggest fewer 

Preble’s meadow jumping mice were 

found on sites with trails than on sites 

without trails. While temporal and 

spatial variation in Preble’s meadow 

jumping mouse numbers resulted in low 

precision of population estimates and 

weak statistical support for a negative 

trail effect, the authors considered the 

magnitude of the potential effect 

sufficient to encourage careful 

management and additional research 

(Meaney et al. 2002, pp. 115, 131–132). 

Since the listing of the Preble’s meadow 

jumping mouse in 1998, a dozen 

recreational trail projects with proposed 

impacts to Preble’s meadow jumping 

mouse habitat in Larimer, Boulder, 

Douglas, and El Paso Counties, 

Colorado, have been addressed through 

section 7 consultations or HCPs. An 

additional 24 trail projects have been 

permitted under the Douglas County 

Regional HCP. As human populations 

continue to increase (as discussed 

above), we anticipate increased demand 

for recreational development in public 

open space and on conservation 

properties. Without protections afforded 

by the Act, Preble’s meadow jumping 

mouse populations on properties free 

from residential and commercial 

development threats will still be subject 

to widespread threats from future 

recreational development and increased 

human use. 

Many utility lines (sewer, water, gas, 

communication, and electric lines, and 

municipal water ditches) cross Preble’s 

meadow jumping mouse habitat. 

Current and future utility rights-of-way 

through these habitats will cause habitat 

destruction and fragmentation from 

periodic maintenance and new 

construction. Since the listing of the 

Preble’s meadow jumping mouse, 18 

utilities projects adversely affecting the 

Preble’s meadow jumping mouse and its 

habitat have been evaluated through 

section 7 consultations (3 in Wyoming, 

15 in Colorado). In addition, an 

approved HCP with Denver Water 

permits impacts to 34 ha (84 ac) of 

Preble’s meadow jumping mouse habitat 

at multiple sites in Colorado. While 

often more costly than trenching, 

avoidance measures such as directional 

drilling under riparian crossings can 

reduce or avoid impacts to the Preble’s 

meadow jumping mouse. If the Preble’s 

meadow jumping mouse were to be 

delisted, we do not anticipate that 

project operators would voluntarily 

directionally drill to avoid Preble’s 

meadow jumping mouse habitat. 

Overall, we believe threats related to 

transportation, recreation, and other 

rights of way through habitat are 

directly related to human population 

pressures. Thus, we expect these issues 

will have substantial impacts to Preble’s 

meadow jumping mouse populations in 

Colorado, but only minimal impacts to 

Preble’s meadow jumping mouse 

populations in Wyoming. 

Hydrologic Changes. Establishment 

and maintenance of riparian plant 

communities are dependent on the 

interactions between surface-water 

dynamics, groundwater, and riverchannel processes (Gregory et al. 1991, 

pp. 542–545). Changes in hydrology can 


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alter the channel structure, riparian 

vegetation, and valley-floor landforms 

(Gregory et al. 1991, pp. 541–542; Busch 

and Scott 1995, p. 287). Thus, changes 

in the timing and abundance of water 

can be detrimental to the persistence of 

the Preble’s meadow jumping mouse in 

these riparian habitats due to resultant 

changes in vegetation (Bakeman 1997, p. 

79). Changes in hydrology may occur in 

many ways, but two of the more 

prevalent are the excessively high and 

excessively low runoff cycles in 

watersheds with increased areas of 

paved or hardened surfaces, and 

disruption of natural flow regimes 

downstream of dams, diversions, and 

alluvial wells (Booth and Jackson 1997, 

pp. 3–5; Katz et al. 2005, pp. 1019–

1020). 

Urbanization can dramatically 

increase frequency and magnitude of 

flooding while decreasing base flows 

(the portion of stream flow that is not 

surface runoff and results from seepage 

of water from the ground into a channel 

slowly over time; base flow is the 

primary source of running water in a 

stream during dry weather) (Booth and 

Jackson 1997; pp. 8–10; National 

Research Council 2002, pp. 182–186). 

Infiltration of precipitation is greatly 

reduced by increases in impervious 

surfaces. The magnitude of peak flows 

increases in urban areas as water runs 

off as direct overland flow. Increased 

peak flows can exceed the capacity of 

natural channels to transport flows, 

trigger increased erosion, and degrade 

habitat (Booth and Jackson 1997, pp. 3–

5). Changes in hydrology associated 

with urbanization can result in channel 

downcutting, lowering of the water table 

in the riparian zone, and creation of a 

‘‘hydrologic drought,’’ which in turn 

alters vegetation, soil, and microbial 

processes (Groffman et al. 2003, p. 317). 

Meanwhile, reduced infiltration results 

in reduced groundwater recharge, 

reduced groundwater contributions to 

stream flow, and, ultimately, reduced 

base flows during dry seasons (National 

Research Council 2002, p. 182; 

Groffman et al. 2003, p. 317). 

Established methods of mitigating 

downstream impacts of urban 

development, such as detention basins, 

have only limited effectiveness; 

downstream impacts are probably 

inevitable without limiting the extent of 

watershed development (Booth and 

Jackson 1997, p. 17). 

In response to altered hydrology, 

stormwater-management, flood-control, 

and erosion-control efforts occur along 

many streams within the former and 

current range of the Preble’s meadow 

jumping mouse. The methods used 

include channelization; construction of 

detention basins, outfall structures, drop 

structures, riprap banks, impervious 

cement channels; and other structural 

stabilization. Structural stabilization 

methods designed to manage runoff and 

control erosion can increase the rate of 

stream flow, shorten channel length, 

narrow riparian areas, destroy riparian 

vegetation, and prevent or prolong the 

time required for vegetation 

reestablishment (Booth and Jackson 

1997, p. 4). These impacts may affect 

plant composition, soil structure, and 

physiography of riparian systems to the 

point where habitat supporting the 

Preble’s meadow jumping mouse is so 

altered that populations can no longer 

persist. Pague and Grunau (2000) 

considered ‘‘bank stabilization’’ to be a 

high-priority issue for the Preble’s 

meadow jumping mouse in Weld and El 

Paso Counties. Since the listing of the 

Preble’s meadow jumping mouse, 22 

stormwater management, stream 

stabilization, or outfall structure 

projects with impact to Preble’s meadow 

jumping mouse habitat have been 

addressed through formal section 7 

consultations in Colorado; none have 

occurred in Wyoming. 

The Preble’s meadow jumping 

mouse’s apparent absence downstream 

from most areas of extensive 

urbanization (including Cheyenne, 

Wyoming, and Fort Collins, Longmont, 

Boulder, Golden, Denver, Parker, and 

Colorado Springs, Colorado) may be 

attributable to such changes in 

hydrology. Corn et al. (1995, p. 14) and 

Schorr (2001, p. 30) expressed concern 

over the integrity of protected riparian 

habitats on Monument Creek and its 

tributaries through the U.S. Air Force 

Academy (Academy) because of 

development activities upstream. In 

2007, all eastern tributaries of 

Monument Creek on the Academy 

experienced adverse impacts to 

occupied Preble’s meadow jumping 

mouse habitat due to erosive head 

cutting, channel degradation, and 

impacts to vegetation that were 

attributable to regional stormwater 

management, and commercial and 

residential development (Mihlbachler 

2007). 

Efforts to restore degraded riparian 

habitats have occurred in Colorado, in 

part to benefit the Preble’s meadow 

jumping mouse. Efforts to restore 

Preble’s meadow jumping mouse habitat 

through a 0.86 km (0.54 mi) urban 

stream reach of East Plum Creek, 

Douglas County appear to have 

increased vegetation cover and Preble’s 

meadow jumping mouse numbers 

(Bakeman 2006, pp. 4, 8). Similarly, 

recent projects on Cherry Creek, Douglas 

County, have attempted to restore 

groundwater levels and downcut 

channels in or near Preble’s meadow 

jumping mouse habitat by employing 

rock or sheet pile drop structures. 

If we were to delist the Preble’s 

meadow jumping mouse, we believe 

that runoff-related impacts to riparian 

habitats within and downstream of 

development may increase in areas of 

high development, such as along 

Colorado’s Front Range urban corridor, 

and that restoration of impacted riparian 

systems would be less likely to occur. 

At the time of listing, we stated that 

the Preble’s meadow jumping mouse 

depended on vegetative habitat that was 

in turn dependent on physical factors 

including surface flows and 

groundwater. Water development and 

management in its various forms alters 

vegetation composition and structure, 

riparian hydrology, and flood-plain 

geomorphology directly, as well as 

through alterations to habitat located 

downstream; these alterations often, but 

not always, have adverse impacts to the 

Preble’s meadow jumping mouse (63 FR 

26517 May 13, 1998). The creation of 

irrigation reservoirs at the expense of 

native wetlands is a factor that 

negatively affected Preble’s meadow 

jumping mouse populations over the 

previous century (Fitzgerald et al. 1994, 

p. 293). Reservoirs with barren 

shorelines can create barriers to Preble’s 

meadow jumping mouse movement and 

fragment populations along stream 

corridors. Current and future reservoir 

construction is necessary to respond to 

municipal water needs. By 2030, 

municipal and industrial demand for 

water in Colorado will increase 60 

percent, by 578 million cubic meters 

(m3) (469,000 acre-feet (af)) yearly in the 

South Platte River drainage and by 41 

percent, 133 million m3 (108,000 af) 

yearly in the Arkansas River drainage 

(Colorado Water Conservation Board 

2004). Even under the most optimistic 

scenarios, the Colorado Water 

Conservation Board (2004, p. 13–17) 

estimated a shortfall relative to 

municipal and industrial demands of 

111 million m3 (90,000 af) of water in 

the South Platte drainage and 22 million 

(m3) (18,000 af) in the Arkansas 

drainage by 2030. Pague and Grunau 

(2000) considered hydrological impacts 

(water quality, flow regime, and 

groundwater) to be a high-priority issue 

to the Preble’s meadow jumping mouse 

in all Colorado counties supporting 

populations. 

Three water projects currently being 

considered may significantly affect 

Preble’s meadow jumping mouse habitat 

including: The proposed expansions of 

existing Halligan and Seaman reservoirs 

in the Cache La Poudre drainage, 


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Larimer County, Colorado, and storage 

reallocation at Chatfield Reservoir, in 

the Upper South Platte drainage, 

Jefferson and Douglas Counties, 

Colorado. Options being considered at 

Halligan Reservoir could inundate up to 

4.0 km (2.5 mi) of Preble’s meadow 

jumping mouse habitat and affect 

Preble’s critical habitat at the site of the 

proposed dam. At Seaman Reservoir, 

the currently favored option would 

inundate about 4.0 km (2.5 mi) of 

Preble’s meadow jumping mouse critical 

habitat, while another option being 

considered would inundate about 11 km 

(7 mi). Options being investigated at 

Chatfield Reservoir have generated a 

preliminary estimate that up to 130 ha 

(330 ac) of existing Preble’s meadow 

jumping mouse habitat, including 

almost 28 ha (70 ac) of critical habitat, 

would be inundated. 

In Wyoming, estimates of projected 

water use in the Platte River Basin 

through 2035, range from a 38 million 

m3 (31,000 af) decrease (2 percent) to a 

90 million m3 (73,000 af) increase (6 

percent) (Wyoming Water Development 

Commission 2006, p. 10). No significant 

reservoir projects are currently planned 

within Preble’s habitat in Wyoming. 

While the Platte River Plan identifies 

‘‘upper Laramie River storage’’ as a 

future storage opportunity (Wyoming 

Water Development Commission 2006, 

p. 31), potential impacts to Preble’s 

meadow jumping mouse are uncertain 

based on limited knowledge of the 

subspecies’ occurrence in the drainage 

and uncertainty regarding the location 

of any future water projects. 

Beyond direct effects to the Preble’s 

meadow jumping mouse and its habitat 

through construction or inundation, 

changes in flows related to water 

diversion, storage, and use also affect 

riparian habitats downstream in a 

variety of ways. As flows are captured 

or diverted, or as groundwater supplies 

are depleted through wells, natural flow 

patterns are changed, and more xeric 

plant communities replace the riparian 

vegetation. Sediment transport is 

disrupted by on-stream reservoirs. Loss 

of sediment encourages channel 

downcutting, which in turn affect 

groundwater levels (Katz et al. 2005, p. 

1020). The resulting conversion of 

habitats from moist or mesic, shrubdominated systems to drier grass-or 

forb-dominated systems make the area 

less suitable for the Preble’s meadow 

jumping mouse. 

Given the projected future demands 

for water, we believe that major water 

development projects affecting the 

Preble’s meadow jumping mouse in 

Colorado would likely occur regardless 

of whether the subspecies remains 

listed. Measures to minimize and 

compensate for impacts specific to the 

Preble’s meadow jumping mouse and its 

habitat are less likely to be incorporated 

into project plans if the subspecies were 

to be delisted. Fewer and smaller 

projects are likely to occur in Wyoming. 

Aggregate Mining. At the time of 

listing, we cited alluvial aggregate 

mining as a threat to the Preble’s 

meadow jumping mouse. Aggregate 

mining is focused on floodplains, where 

these mineral resources most commonly 

occur, and specifically on the same 

gravel deposits that may provide 

important hibernation sites (63 FR 

26517, May 13, 1998). Alluvial aggregate 

mining continues to be a threat to the 

Preble’s meadow jumping mouse in 

Colorado. Alluvial aggregate extraction 

may produce long-term changes to 

Preble’s meadow jumping mouse habitat 

by removing (often permanently) shrub 

and herbaceous vegetation, and by 

altering hydrology. Often, mined pits 

are constructed with impervious liners 

and converted to water reservoirs after 

aggregate is removed. This conversion 

precludes restoration of riparian 

shoreline vegetation and alters adjacent 

groundwater flow. 

Since listing, we have conducted 

formal consultation under section 7 of 

the Act regarding impacts to the Preble’s 

meadow jumping mouse at two 

aggregate mines in Colorado and we 

have worked to avoid impacts at others. 

At Rocky Flats National Wildlife Refuge 

(NWR), private aggregate mining 

activities could affect Preble’s meadow 

jumping mouse habitat directly or 

through alteration of hydrology along 

Rock Creek. While aggregate mining 

continues to affect floodplains in the 

Colorado Front Range, many project 

sites are along downstream reaches of 

larger streams and rivers where Preble’s 

meadow jumping mouse populations 

appear absent. Pague and Grunau (2000) 

considered ‘‘rock and sand extraction’’

to be a high-priority issue in Weld, 

Jefferson, and Douglas Counties. In 

Wyoming, aggregate mining has not 

been an issue in Preble’s meadow 

jumping mouse habitat and we have no 

information on any proposed mines in 

this portion of its range. 

Overall, we believe threats related to 

aggregate mining are likely to be more 

intense in areas in close proximity to 

residential and commercial 

development. Thus, we expect this issue 

will have an impact on Preble’s meadow 

jumping mouse populations in 

Colorado. In Wyoming, we expect 

aggregate mining will have little, if any, 

effect on Preble’s meadow jumping 

mouse populations as future 

development is projected to be far less. 

Agriculture. At the time of listing we 

cited conclusions by Compton and 

Hugie (1993a; 1993b) that human 

activities, including conversion of 

grasslands to farms and livestock 

grazing, had adversely impacted 

Preble’s meadow jumping mouse. They 

concluded that development of irrigated 

farmland had a negative impact on 

Preble’s meadow jumping mouse 

habitat, and that any habitat creation it 

produced was minimal (Compton and 

Hugie 1993a; Compton and Hugie 

1993b). In general, negative trapping 

results suggest that the Preble’s meadow 

jumping mouse does not occur in areas 

cultivated for row crops. Historically, 

the rapid rate of native habitat 

conversion to row crops likely had a 

significant adverse impact on the 

Preble’s meadow jumping mouse. 

Because conversion of native habitat to 

row crops has become increasingly rare 

in both Colorado and Wyoming (U.S. 

Department of Agriculture 2000, Tables 

2, 3, & 9), such conversions are unlikely 

to present a similar threat in the future 

in any portion of the subspecies range. 

The Preble’s meadow jumping mouse 

uses native grass and alfalfa hayfields 

when they are in or adjacent to suitable 

riparian habitat. This juxtaposition is 

often the case, since hay production 

requires large amounts of water. 

Mowing of hay may directly kill or 

injure Preble’s meadow jumping mice, 

reduce food supply (since many plants 

will not mature to produce seed), and 

remove cover. Late season mowing may 

be especially problematic, because 

Preble’s meadow jumping mice are 

approaching hibernation and their 

nutritional needs are high (Clippinger 

2002, p. 72). Additionally, hay 

production may preclude growth of 

willows and other shrubs that are 

important as hibernation habitat for the 

Preble’s meadow jumping mouse. 

Hayfields often are irrigated through 

ditch systems. The Preble’s meadow 

jumping mouse uses overgrown water 

conveyance ditches and pond edges, 

and may use agricultural ditches as 

dispersal routes (Meaney et al. 2003, pp. 

612–613). Ditch maintenance activities 

may kill individual Preble’s meadow 

jumping mice and periodically alter 

their habitat. Existing special 

regulations at 50 CFR 17.40(1) exempt 

certain ditch maintenance operations 

from take prohibitions of the Act in 

recognition that habitat the ditches 

provide is dependent on the ditches 

retaining their function. Preble’s 

meadow jumping mouse populations 

have persisted in areas hayed for many 

years (Taylor 1999). Haying operations 

that allow dense riparian vegetation to 


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remain in place are likely compatible 

with persistence of Preble’s meadow 

jumping mouse populations. 

Impacts to riparian habitat from 

livestock are well documented in the 

scientific literature (Kauffman and 

Krueger 1984, pp. 431–435; Armour et 

al. 1991, pp. 7–11; Fleischner 1994, pp. 

629–638; Belsky et al. 1999, pp. 419–

431; Freilich et al. 2003, pp. 759–765). 

Livestock have damaged 80 percent of 

stream and riparian ecosystems in the 

western United States (Belsky et al. 

1999, p 419.). Adverse impacts of 

grazing include changes to stream 

channels (downcutting, trampling of 

banks, increased erosion), to flows 

(increased flow and velocity, decreased 

late-season flow), to the water table 

(lowering of the water table), and to 

vegetation (loss to grazing, trampling, 

and through altered hydrology) 

(Kauffman and Krueger 1984, pp. 432–

435). 

Impacts from cattle grazing to other 

jumping mice subspecies have been 

documented by Frey (2005), Giuliano 

and Homyack (2004), and Medin and 

Clary (1989). Ryon (1996, p. 3) cited 

livestock grazing as a contributor to the 

lack of structural habitat diversity he 

observed on historical Preble’s meadow 

jumping mouse sites in Colorado. On a 

working ranch in Douglas County, 

Colorado, Preble’s meadow jumping 

mice were detected within cattle 

exclosures, but not on grazed areas. 

Previous trapping had documented 

Preble’s meadow jumping mice 

upstream and downstream, but not on 

the ranch (Ensight Technical Services 

2004, p. 9). On private lands in Douglas 

County, Colorado, Pague and 

Schuerman (1998, pp. 4–5) observed a 

swift rate of residential land 

development and significant 

fragmentation of habitat, but noted that 

in some cases accompanying secession 

of grazing had allowed recovery of 

degraded riparian habitats. 

In Colorado, City of Boulder lands 

endured intensive grazing, farming, or 

haying regimes until they became part 

of the Boulder Open Space system. 

Grazing and haying, used as land 

management tools, continue on Boulder 

Open Space sites currently supporting 

the Preble’s meadow jumping mouse. In 

their study of small mammals on 

Boulder Open Space, Meaney et al. 

(2002, p. 133) found no adverse effects 

of managed grazing on abundance of 

individual small mammal species or on 

species diversity. 

Cattle can undoubtedly greatly affect 

herbaceous vegetation, especially in 

times of drought; grazing practices that 

assure maintenance of riparian shrub 

cover may be a key consideration in 

maintaining Preble’s meadow jumping 

mouse populations (Ensight Technical 

Services 2004, p. 9). The recent drought, 

in combination with grazing, may have 

had an increased effect on Preble’s 

meadow jumping mouse habitat. 

Overgrazing threats are not limited to 

large livestock producing operations. On 

subdivided ranch properties, often 

termed ‘‘ranchettes,’’ horses and other 

livestock can heavily affect the small 

tracts within which they are fenced 

(Pague and Grunau 2000, pp. 1–14). 

Pague and Grunau (2000) considered 

‘‘high impact livestock grazing’’ to be a 

high-priority issue for the Preble’s 

meadow jumping mouse in Larimer, 

Weld, Elbert, and El Paso Counties in 

Colorado, largely due to the projected 

increase in such ranchettes. 

In Wyoming, where large-scale 

commercial ranching is more prevalent 

in the Preble’s meadow jumping 

mouse’s range than in Colorado, 

overgrazing is thought to occur 

sporadically across the landscape, most 

obviously where cattle congregate in 

riparian areas in winter and spring. 

Grazing has occurred within Preble’s 

meadow jumping mouse habitat for 

many decades, and populations of 

Preble’s meadow jumping mice have 

been documented on sites with a long 

history of grazing. For example, jumping 

mice were trapped at 18 of 21 sites on 

True Ranches properties (mice from 14 

of these sites have since been confirmed 

as Preble’s meadow jumping mice (King 

et al. 2006b, p. 4351)), primarily within 

sub-irrigated hay meadows that have 

been subjected to livestock grazing and 

hay production for approximately 100 

years (Taylor 1999, p. 5). 

At the time of listing, we addressed 

overgrazing by livestock, stating that it 

may have caused significant impacts to 

Preble’s meadow jumping mouse 

habitat, but that timing and intensity of 

grazing were probably important to 

some degree in maintaining habitat and 

that maintenance of woody vegetative 

cover could be key (63 FR 26517, May 

13, 1998). Overgrazing was thought to 

have eliminated the Preble’s meadow 

jumping mouse from much of its former 

Wyoming range (Clark and Stromberg 

1987, p. 185; Compton and Hugie 

1993b, p. 4). Trapping efforts since 

listing have greatly expanded our 

understanding of the subspecies’ range 

in Wyoming, suggesting that our 

assertions that grazing eliminated 

Preble’s from these areas were incorrect. 

As suggested by Bakeman (1997, p. 

79) and Pague and Grunau (2000, p. 1–

17), and as supported by the examples 

above, grazing is compatible with 

Preble’s meadow jumping mouse when 

timing and intensity are appropriately 

managed. We now believe that 

agricultural operations that have 

maintained habitat supportive of 

Preble’s meadow jumping mouse 

populations are consistent with 

conservation and recovery of the 

subspecies. In recognition of this, we 

adopted in 2001 special regulations at 

50 CFR 17.40(1) which exempted 

existing agricultural activities, including 

grazing, plowing, seeding, cultivating, 

minor drainage, burning, mowing, and 

harvesting, from the prohibitions of the 

Act. The exemption does not apply to 

new agricultural activities or to those 

that expand the footprint or intensity of 

the activity. We established the 

exemption to provide a positive 

incentive for agricultural interests to 

participate in voluntary conservation 

activities and to support surveys and 

studies designed to determine status, 

distribution, and ecology of Preble’s 

meadow jumping mouse, which in turn 

could lead to more effective recovery 

efforts. 

The number of cattle in counties 

currently known to support the Preble’s 

meadow jumping mouse in Wyoming 

totaled 270,000 head in 2006 (National 

Agriculture Statistics Service 2007). 

Cattle numbers appear stable in Albany, 

Converse, and Laramie Counties, but 

higher than the average for the last 20 

years in Platte County. Cattle numbers 

in Colorado counties supporting the 

Preble’s meadow jumping mouse totaled 

666,000 head in 2006, but they total 

only 116,000 head if Weld County, 

where few Preble’s meadow jumping 

mice are thought to persist, is excluded 

(National Agriculture Statistics Service 

2007). Excluding Weld, all of these 

Colorado counties have shown a marked 

downward trend in cattle numbers over 

the past 20 years, reflecting human 

development on former agricultural 

lands (National Agriculture Statistics 

Service 2007). 

Overall, we expect traditional grazing 

operations to continue in Wyoming. 

Such operations have generally proven 

compatible with Preble’s meadow 

jumping mice as timing and intensity 

have been managed appropriately. This 

management has taken place without 

ESA oversight as allowed in the special 

regulations at 50 CFR 17.40(1). We have 

no reason to believe the management of 

these facilities will change significantly 

in the future. 

In Colorado, many large ranch 

properties are being subdivided into 

‘‘ranchettes.’’ These small tracts can be 

heavily affected by concentrated grazing 

pressures. We believe that this 

represents a widespread threat to 

significant areas of Colorado, where an 

increase in rural development is forecast 


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in the foreseeable future. Based on 

growth projections, subdivision of 

ranches is expected to be minimal in 

portions of Wyoming where the Preble’s 

meadow jumping mouse exists. 

Summary. Within Colorado, human 

land uses within the Preble’s meadow 

jumping mouse’s range have destroyed, 

degraded, and fragmented habitat and 

continue to do so. While protections of 

the Act have avoided, minimized, and 

helped to compensate for direct human 

land-use impacts to occupied Preble’s 

meadow jumping mouse habitat, 

secondary impacts to riparian habitats 

have likely diminished the areas that are 

capable of sustaining Preble’s 

populations. Given the projected future 

growth rates in Colorado, and absent 

protections associated with Federal 

activities and listing under the Act, we 

believe that threats posed by human 

development activities discussed above 

would rise dramatically following 

delisting. Most of the new Preble’s 

meadow jumping mouse sites 

documented since listing in Colorado 

are subject to the same level of threats 

discussed above for the Colorado 

portion of the range in general and do 

not change our conclusion as to the 

current and future conservation status of 

the subspecies in this portion of its 

range. Regulatory mechanisms that 

could help reduce such negative 

impacts, while currently limited, are 

discussed under Factor D below. 

In Wyoming, the Preble’s meadow 

jumping mouse appears to be much 

more widely distributed than previously 

assumed, while current and future 

threats to habitat and range appear 

limited. Such impacts to the Wyoming 

portion of the subspecies’ range are 

likely to be minor with only small and 

localized effects. Therefore, we believe 

that present or threatened destruction, 

modification, or curtailment of the 

Preble’s meadow jumping mouse habitat 

and range in Wyoming do not suggest 

that this subspecies is likely to become 

endangered within the foreseeable 

future throughout all of its range. 

B. Overutilization for Commercial, 

Recreational, Scientific, or Educational 

Purposes 

The Preble’s meadow jumping mouse 

is not collected for commercial or 

recreational reasons. Some collection of 

specimens occurs for scientific and 

educational purposes, but currently 

only through permits issued by the 

Service, CDOW, or WGFD. Although 

unintentional mortalities have resulted 

from capture and handling of Preble’s 

meadow jumping mice by permitted 

researchers, we believe that the level of 

take associated with this activity does 

not rise to the level that would affect 

populations of the subspecies, nor is it 

likely to do so if we remove the 

protections of the Act. 

C. Disease or Predation 

At the time of listing, we had no 

evidence of disease causing significant 

impacts to the Preble’s meadow jumping 

mouse (63 FR 26517, May 13, 1998). No 

further evidence exists that any parasite 

or disease has caused a significant 

impact to populations. While plague 

relationships for most North American 

rodents are poorly understood, plague 

may interact synergistically with other 

natural and human-induced 

disturbances, increasing risk of local 

extirpation and rangewide extinction 

(Biggins and Kosoy 2001, p. 913). Plague 

has not been documented in the Preble’s 

meadow jumping mouse. However, 

Pague and Grunau (2000, pp. 1–19) 

considered disease to be a potentially 

high-priority issue for the Preble’s 

meadow jumping mouse. They cited 

unknown resistance of the Preble’s 

meadow jumping mouse to plague and 

other diseases, and noted that small 

populations could be especially 

vulnerable to effects of an epizootic. 

Should disease materialize into a 

substantive issue, we believe 

populations in Colorado would be at 

higher risk because development 

pressures in this portion of the range are 

more likely to result in small, 

fragmented, and unsustainable 

populations. 

At the time of listing, we addressed 

potential predators of the Preble’s 

meadow jumping mouse whose 

densities could increase in the suburban 

or rural environment, including striped 

skunk (Mephitis mephitis), raccoon 

(Procyon lotor), and the domestic cat 

(Felis catus) (63 FR 26517, May 13, 

1998). Increased impacts of native and 

exotic predators that accompany rural 

development can affect species viability 

(Hansen et al. 2005, p. 1899). We noted 

opinions that free-ranging domestic cats 

and feral cats locally presented a 

problem to Preble’s meadow jumping 

mouse populations. Where predator 

populations are increased through 

human land uses, they may contribute 

to the loss or decrease of Preble’s 

meadow jumping mouse. Generally, we 

have found proponents of new 

residential developments near Preble’s 

meadow jumping mouse habitat to be 

receptive to prohibitions on free-ranging 

cats and dogs (Canis domesticus) when 

negotiating minimization measures 

through section 7 of the Act. However, 

enforcement is often through covenants 

administered by homeowners’

associations with uncertain success. If 

the Preble’s meadow jumping mouse 

were to be delisted and Federal 

protection under the Act discontinued, 

similar covenants on new development 

in and near Preble’s meadow jumping 

mouse habitat would be less likely, and 

existing covenants may not be as strictly 

enforced. Beyond previously known or 

anticipated predators of jumping mice, 

introduction of non-native bullfrogs 

(Rana catesbiana) in Colorado has 

resulted in predation on Preble’s 

meadow jumping mice (Trainor 2004, p. 

58). However, we have no information 

to suggest that predation from bullfrogs 

has affected Preble’s meadow jumping 

mouse populations. 

While many uncertainties remain 

regarding disease and predation, we 

believe the best available scientific and 

commercial data suggest that disease is 

most likely to only be a factor in small 

and fragmented populations, and that 

increases in predation will likely only 

contribute to the reduction, 

fragmentation, and loss of Preble’s 

meadow jumping mouse populations 

when such populations are exposed to 

increased human presence. As noted 

above, increased human presence is 

expected to be a significant issue in 

Colorado and of minimal concern in 

Wyoming. Thus, we expect these issues 

have the potential to meaningfully affect 

Preble’s meadow jumping mouse 

populations in developing areas of 

Colorado, but comparable impacts in 

Wyoming are not expected. 

D. The Inadequacy of Existing 

Regulatory Mechanisms 

This factor considers the regulatory 

mechanisms that would remain in place 

in the absence of the Act’s protective 

measures. Current and likely future 

protections are considered. If the 

protections of the Act are removed, the 

Service has no assurances previous 

conservation commitments made under 

sections 7 or 10 of the Act would remain 

in place. 

At the time of listing, we cited the 

lack or ineffectiveness of laws and 

regulations protecting the Preble’s 

meadow jumping mouse and its habitat 

(63 FR 26517, May 13, 1998). Protective 

measures discussed below include 

Federal, State, and local protections. 

Federal Protections. Existing Federal 

laws, such as the Clean Water Act (33 

U.S.C. 1251 et seq.), Federal Power Act 

(16 U.S.C. 791a et seq.), Fish and 

Wildlife Coordination Act (16 U.S.C. 

661 et seq.), National Forest 

Management Act (16 U.S.C. 1600 et 

seq.), Federal Land Policy and 

Management Act (43 U.S.C. 1701 et 

seq.), Food Security Act (16 U.S.C. 3801 

et seq.), and National Environmental 


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Policy Act (42 U.S.C. 4321 et seq.), 

provide limited protection for non-listed 

species. 

Section 404 of the Clean Water Act 

generally requires avoidance, 

minimization (when practicable), and 

mitigation of adverse impacts to 

jurisdictional wetlands and waters of 

the United States associated with filling. 

Human impacts to jurisdictional 

wetlands may be permitted when 

alternatives that would avoid wetlands 

are found not to be practicable. Section 

404 of the Clean Water Act does not 

apply to non-jurisdictional waters or 

wetlands that include some streams 

corridors known to support the Preble’s 

meadow jumping mouse (most notably 

Running Creek and its tributaries in 

Elbert County, Colorado, but potentially 

on other streams with intermittent flows 

or where there is no regular connection 

to waters of the United States). In these 

cases, activities effecting these waters or 

wetlands would not require Federal 

permits under Section 404 of the Clean 

Water Act. In addition, Section 404 of 

the Clean Water Act provides no 

comparable safeguards for nearby 

uplands used by the Preble’s meadow 

jumping mouse. Thus, the Clean Water 

Act provides only limited protection of 

habitats utilized by the Preble’s meadow 

jumping mouse and is not capable of 

substantially reducing threats to 

individual Preble’s populations or to the 

subspecies as a whole. 

On lands administered by the U.S. 

Forest Service and U.S. Bureau of Land 

Management, the current status of the 

Preble’s meadow jumping mouse as 

threatened invokes management 

priorities in accordance with the Act. If 

delisted, these protections would no 

longer apply. However, Federal landmanagement agencies, through their 

regulations, policies, and management 

plans, work to ensure long-term 

protection of all listed species. Of the 

three National Forests supporting 

Preble’s meadow jumping mouse 

populations, the Medicine Bow—Routt 

National Forest has a forest management 

plan that includes standards and 

guidelines specific to conservation of 

the Preble’s meadow jumping mouse. 

The Arapahoe-Roosevelt National Forest 

and the Pike-San Isabel National Forest 

have forest plans that predate the listing 

of the Preble’s meadow jumping mouse 

(Warren 2007). If delisted, the Preble’s 

meadow jumping mouse would likely 

be considered a subspecies warranting 

conservation concern by Federal landholding agencies and, as such, retain 

some continued degree of conservation 

priority. 

On military installations, the Sikes 

Act Improvement Act of 1997 (16 U.S.C. 

670a et seq.) requires each facility that 

includes land and water suitable for the 

conservation and management of 

natural resources to complete an 

Integrated Natural Resources 

Management Plan (INRMP). This plan 

must integrate implementation of the 

military mission of the installation with 

stewardship of the natural resources 

found there. In both Colorado and 

Wyoming, this process has provided the 

opportunity to consider the potential 

impacts of military actions on the 

Preble’s meadow jumping mouse. 

Warren Air Force Base in Laramie 

County, Wyoming, has an INRMP and a 

conservation and management plan. 

However, the base may only support the 

western jumping mouse. The Air Force 

Academy in El Paso County, Colorado, 

has an INRMP in place, a conservation 

and management plan, and a 

programmatic consultation under 

section 7 of the Act, which provides 

guidance for Air Force management 

decisions for certain activities that may 

affect the subspecies. Research on the 

Preble’s meadow jumping mouse is 

ongoing at the Academy; the 

conservation and management plan is 

designed to be updated as new 

information is collected. Both plans are 

designed to be in place for 5 years. The 

emphasis given to conservation of the 

Preble’s meadow jumping mouse in 

these plans may decline in the future if 

the subspecies were to be delisted. 

The presence of Preble’s meadow 

jumping mouse has been documented at 

two of the Service’s NWRs. We manage 

the Rocky Flats NWR, near Boulder, 

Colorado, in a manner consistent with 

conservation of the Preble’s meadow 

jumping mouse. This management is 

unlikely to change if the Preble’s 

meadow jumping mouse were to be 

delisted. 

More recently, a single Preble’s 

meadow jumping mouse as well as 

western jumping mice have been 

confirmed from Hutton Lake NWR near 

Laramie, Wyoming. Because this 

subspecies was only recently 

documented on Huttom Lake NWR, the 

subspecies needs are not explicitly 

addressed in management documents 

(Timberman 2007). While it is unknown 

if ongoing management (primarily 

waterfowl oriented) is consistent with 

the subspecies’ needs, the refuge has 

expressed a willingness to provide for 

the needs of the subspecies in the future 

(Timberman 2007). 

Service-approved HCPs and their 

incidental take permits contain 

management measures and protections 

for identified areas that protect, restore, 

and enhance the value of these lands as 

habitat for the Preble’s meadow jumping 

mouse. These measures, which include 

explicit standards to avoid, minimize, 

and mitigate any impacts to the covered 

(sub)species and its habitat, are 

designed to ensure that the biological 

value of covered habitat for the Preble’s 

meadow jumping mouse is maintained, 

expanded, or improved. Large regional 

HCPs expand upon the basic 

requirements set forth in section 

10(a)(1)(B) of the Act and reflect a 

voluntary, cooperative approach to 

large-scale habitat and (sub)species 

conservation planning. The primary 

goal of such HCPs is to provide for the 

protection and management of habitat 

essential for the conservation of the 

(sub)species while directing 

development to other areas. In any HCP, 

permittees may terminate their 

participation in the agreement and 

abandon the take authorization set forth 

in the permit. 

To date, we have approved 19 single 

species HCPs for the Preble’s meadow 

jumping mouse, all in Colorado. 

Eighteen of the associated permits allow 

approximately 280 ha (700 ac) of 

permanent or temporary impact to 

Preble’s meadow jumping mouse 

habitat, and preserve or enhance habitat 

to offset impacts. The largest of these, 

the approved HCP for Douglas County 

and the Towns of Castle Rock and 

Parker, allows impacts of up to 170 ha 

(430 ac), in exchange for the acquisition 

of 9 km (15 mi) of stream and 455 ha 

(1,132 ac) of habitat, was acquired and 

preserved for the long-term benefit of 

the Preble’s meadow jumping mouse. 

The remaining HCP, issued in January 

2006, is the Livermore Area HCP in 

Larimer County. The planning area for 

this HCP includes a large portion of 

Larimer County, approximately 1,940 

square km (750 square mi), including a 

Preble’s meadow jumping mouse 

‘‘conservation zone’’ estimated at 

approximately 324 km (201 mi) of 

stream and 8,570 ha (21,320 ac). The 

HCP cites protection of 114 km (71 mi) 

of stream, mostly on CDOW lands; 

however, it is not clear what proportion 

of these areas support Preble’s. Local 

landowners and public agencies holding 

land within the boundaries of this HCP 

may opt for coverage under the HCP and 

receive take permits for activities 

consistent with the HCP. The Livermore 

Area HCP is designed to support current 

land uses, including ranching and 

farming. However, inclusion of 

landowners is optional, and they may 

choose to pursue land uses inconsistent 

with those specified in the HCP. Thus 

far, we have issued no individual 

permits under this HCP. 

Of the two regional HCPs in the 

process of being developed, the El Paso 


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County effort is proceeding slowly and 

the Boulder County effort appears to be 

on hold. It is unlikely that these 

conservation plans will be completed or 

implemented if the Preble’s meadow 

jumping mouse does not remain listed 

under the Act. 

State Protections. Under the nongame 

provisions of the CDOW Regulations 

(Chapter 10, Article IV) the Preble’s 

meadow jumping mouse currently may 

only be taken legally by permitted 

personnel for educational, scientific, or 

rehabilitation purposes. However, if 

delisted, Colorado could rescind its 

current State designation of threatened. 

In Wyoming, continued classification of 

the meadow jumping mouse as a 

‘‘nongame species’’ under Section 11 of 

Chapter 52 (Nongame Wildlife) of the 

Wyoming Game and Fish Commission 

regulations would protect the Preble’s 

meadow jumping mouse from takings 

and sales by allowing the issuance of 

permits only for the purpose of 

scientific collection. As mentioned 

previously in our discussion under 

Factor B, overutilization for commercial, 

recreational, scientific, or educational 

purposes is not now, nor is it likely to 

become a significant threat to the 

subspecies, even if the protections 

afforded the subspecies under Colorado 

and Wyoming laws are removed. 

Numerous State lands (CDOW lands, 

State Park lands, State Land Board 

lands) and mitigation properties (such 

as those of the Colorado Department of 

Transportation) would continue to 

provide a measure of protection for the 

Preble’s meadow jumping mouse should 

it be delisted. While some conservation 

properties may have management 

specifically designed to preserve and 

enhance Preble’s meadow jumping 

mouse habitat, others concentrate more 

on open-space preservation and general 

wildlife-habitat conservation. 

State programs have been available to 

help preserve the Preble’s meadow 

jumping mouse through the acquisition, 

preservation, and management of its 

habitat. These include the Great 

Outdoors Colorado Trust Fund and the 

Species Conservation Trust Fund. In 

comments to the Service, then Colorado 

Department of Natural Resources 

Commissioner, Russell George, stated 

that State and local initiatives could 

provide for conservation of the Preble’s 

meadow jumping mouse, independent 

of Federal oversight. He listed nearly 40 

conservation projects in 5 Front Range 

Colorado counties where the Preble’s 

meadow jumping mouse ‘‘may be 

present’’ (George 2004). The 

conservation value of many of these 

projects is uncertain since most were 

developed without specific regard to the 

Preble’s meadow jumping mouse’s 

distribution and its conservation. 

Local Protections. At the time of 

listing, we pointed out that while a 

myriad of regional or local regulations, 

incentive programs, and open-space 

programs existed, especially in 

Colorado, few specifically protected the 

Preble’s meadow jumping mouse or its 

habitat from inadvertent or intentional 

adverse impacts (63 FR 26517, May 13, 

1998). Many local regulations create a 

process of site-plan review that 

‘‘considers’’ or ‘‘encourages’’

conservation of wildlife, wetlands, and 

other natural habitats. Effectiveness of 

local regulations in maintaining 

naturally functioning riparian corridors 

varies greatly depending on how these 

apparently flexible regulations are 

implemented. Following listing under 

the Act, development and other projects 

in and near Preble’s meadow jumping 

mouse habitat have received increased 

scrutiny from local jurisdictions, often 

in coordination with Service authorities. 

Open-space acquisitions and easements 

have also taken the presence of the 

Preble’s meadow jumping mouse into 

account. It is not clear what level of 

interest in Preble’s meadow jumping 

mouse conservation would continue 

following delisting. Local governments 

would likely relax review procedures 

for projects in known or suspected 

Preble’s meadow jumping mouse 

habitat. Beyond the direct impact to 

Preble’s meadow jumping mouse 

habitat, secondary impacts of 

development (including increased 

recreational use, altered flow regimes 

and groundwater levels, and increase in 

domestic predators) are unlikely to be 

adequately addressed. While certain 

local regulations are designed to 

conserve wetlands or floodplains on 

private lands, it is unlikely they would 

effectively control land uses (grazing, 

mowing, cutting, and burning) that may 

affect the hydrology, vegetation, and 

hibernacula sites on which Preble’s 

depends. The adequacy of such 

protective measures is more important 

within Colorado than Wyoming given 

the intense development pressures in 

the Colorado counties where the 

Preble’s meadow jumping mouse 

occurs. 

Douglas County, Colorado, owns 14 

properties that encompass 24 km (15 

mi) of stream and associated riparian 

habitats potentially beneficial to the 

Preble’s meadow jumping mouse 

(Matthews 2004). Of Douglas County 

streams on non-Federal property within 

the Riparian Conservation Zone, 105 km 

(65 mi), or 23 percent, are under some 

form of permanent protection (Matthews 

2004). However, occurrence of the 

Preble’s meadow jumping mouse on 

many of these properties has not been 

extensively documented. For example, 

while there are 23.4 km (14.5 mi) of 

mapped riparian corridors on the large 

Greenland Ranch conservation property, 

the presence of the Preble’s meadow 

jumping mouse has been documented at 

only two sites. Future conservation 

efforts to augment protected areas and to 

link protection over large expanses of 

connected streams in Douglas County 

could contribute greatly to maintaining 

secure Preble’s meadow jumping mouse 

populations in the Upper South Platte 

and Middle South Platte—Cherry Creek 

drainages. Should the Preble’s meadow 

jumping mouse be delisted, 

management priorities on protected 

lands and direction of future 

conservation efforts would likely 

change. In order to ensure long-term 

management for the Preble’s meadow 

jumping mouse, the Preliminary Draft 

Recovery Plan suggests the Service and 

our partners develop and implement 

long-term management plans and 

cooperative agreements prior to 

delisting (Service 2003b, pp. iv, 33, 39, 

47–47, 51–52). 

Larimer County has acquired or 

secured easements to considerable 

lands, including some properties under 

the Laramie Foothills Project, in 

partnership with The Nature 

Conservancy, the City of Fort Collins, 

and the Legacy Land Trust. While 

conservation efforts have increased, 

especially in the Livermore Valley, 

residential development remains the 

largest threat to Preble’s in the county 

(Pague 2007). The extent to which 

Preble’s meadow jumping mouse 

populations are supported by these 

properties, the fate of remaining private 

lands in the North Fork Cache La 

Poudre River and its tributaries, and the 

ability to link conservation lands and 

traditional agricultural lands supporting 

the Preble’s meadow jumping mouse 

along stream reaches are key to 

protecting the potentially large Preble’s 

meadow jumping mouse population 

thought to exist in this area. 

The City of Boulder, Boulder County, 

and Jefferson County have extensive 

lands protected under their open-space 

programs. While the extent of known 

Preble’s meadow jumping mouse 

occurrences in these counties is limited 

compared to that documented in 

Larimer and Douglas Counties, known 

populations exist on open space 

protected from residential and 

commercial development. 

Summary. In the absence of the Act’s 

protective measures, Federal 

conservation efforts for the Preble’s 

meadow jumping mouse would be 


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largely limited to Federal properties, 

where the subspecies may be 

maintained as a priority subspecies and 

conserved through existing or future 

management plans. 

While state regulations in both 

Colorado and Wyoming would regulate 

killing of Preble’s meadow jumping 

mice, as noted in Factor B above, we do 

not view this as a significant concern 

driving the subspecies long-term 

conservation status. If delisted, State 

and local regulations would do little to 

conserve the Preble’s meadow jumping 

mouse or its habitat on private lands. 

Public land holdings, conservation 

easements, and other conservation 

efforts, past and future, could support 

the Preble’s meadow jumping mouse on 

specific sites. 

In Colorado, the extent and pattern of 

conservation efforts in relation to 

Preble’s meadow jumping mouse 

distribution, and the appropriate 

management of Preble’s meadow 

jumping mouse habitat, would largely 

dictate the long-term viability of 

Preble’s meadow jumping mouse 

populations. At this time, no large 

populations and few medium 

populations, as described in the 

Preliminary Draft Recovery Plan, are 

known to exist in Colorado on 

contiguous stream reaches that are 

secure from development. Management 

plans that specifically address threats to 

the Preble’s meadow jumping mouse are 

few, and management priorities would 

likely change if we were to delist the 

subspecies. Much of the intervening 

private lands would likely be subject to 

development within the foreseeable 

future (this issue is described in more 

detail in Factor A above). If we were to 

delist the subspecies, given current and 

projected levels of protections, we 

believe that most Preble’s meadow 

jumping mouse populations in Colorado 

would not be secure into the foreseeable 

future. 

In Wyoming, the best available 

scientific and commercial information 

suggests that at least one large 

population and two medium 

populations occur in the State as 

recommended in the Preliminary Draft 

Recovery Plan (Service 2003b, pp. 19, 

22). While regulatory measures in 

Wyoming do not guarantee protection of 

these populations, such assurances are 

not needed because threats to the 

Preble’s meadow jumping mouse and 

the subspecies’ habitat are limited for 

the foreseeable future. 

E. Other Natural or Manmade Factors 

Affecting the Subspecies’ Continued 

Existence 

At the time of listing, we judged this 

subspecies susceptible to a number of 

other factors, including impact from 

naturally occurring events such as fire 

and flooding, invasive weeds and weed 

control programs, pesticides and 

herbicides, and secondary impacts 

associated with human-caused 

development (63 FR 26517, May 13, 

1998). For most of these factors, we have 

little more information than we had at 

the time of listing. Additional concerns 

that were not considered at the time of 

listing include the potential for 

competition between the Preble’s 

meadow jumping mouse and the 

western jumping mouse, and future 

effects of changing climate on the 

Preble’s meadow jumping mouse. 

Flooding and fire are natural 

components of the Wyoming and 

Colorado foothills and plains, and 

Preble’s meadow jumping mouse habitat 

naturally waxes and wanes with these 

events. While these natural events may 

affect Preble’s meadow jumping mouse 

populations by killing individuals and 

by destroying riparian and adjacent 

upland habitat on which they depend, 

the effects to vegetation are often 

temporary. Normal flooding and fire 

events also may help maintain the 

vegetative communities that provide 

suitable habitat for the Preble’s meadow 

jumping mouse. Increase in impervious 

surfaces and denuding of vegetation 

caused by human activity can result in 

increased frequency and severity of 

flood events and prevent the reestablishment of favored riparian 

communities. An extreme flood event 

may eliminate an entire Preble’s 

meadow jumping mouse population in 

an affected stream reach or drainage. 

Periodic fire may be of value in 

maintaining riparian, transitional, and 

upland vegetation within Preble’s 

meadow jumping mouse habitat. In a 

review of the effects of grassland fires 

on small mammals, Kaufman et al. 

(1990) found a positive effect of fire on 

meadow jumping mice in one study and 

no effect on the species in another 

study. Fire may regenerate decadent 

willow (Salix sp.) stands along streams 

and encourage higher stem densities 

considered more favorable to the 

Preble’s meadow jumping mouse. 

Long periods of fire suppression 

result in fuel build-up, especially in 

forested areas, and can result in 

catastrophic fires that alter habitat 

dramatically, change the structure and 

composition of the vegetative 

communities, and potentially affect 

large numbers of Preble’s meadow 

jumping mice or multiple populations. 

Following more intense fires, 

precipitation in a burned area may 

degrade Preble’s meadow jumping 

mouse habitat by causing greater levels 

of flooding, erosion, and sedimentation 

along creeks. As habitat redevelops, it 

will likely be reoccupied by the Preble’s 

meadow jumping mouse, assuming that 

there are occupied, connected stream 

reaches where sufficient Preble’s 

meadow jumping mouse populations 

have continued to persist. 

An example of catastrophic fire in 

Preble’s meadow jumping mouse habitat 

occurred in 2002. The Hayman and 

Schoonover fires in Jefferson and 

Douglas Counties, Colorado, 

encompassed over 3,000 ha (7,500 ac) of 

potential Preble’s meadow jumping 

mouse habitat, or approximately 20 

percent of the potential habitat within 

the boundaries of Pike National Forest 

(Mike Elson 2003). Approximately 342 

ha (844 ac) of proposed critical habitat 

were burned. While riparian habitat that 

was lightly burned was expected to 

recover relatively quickly, increases in 

erosion and sedimentation downstream 

have been severe, and may continue to 

affect Preble’s meadow jumping mouse 

habitat for several years. Because of 

severe fire-related impacts, we 

withdrew from the final critical habitat 

designation for the Preble’s meadow 

jumping mouse (68 FR 37275, June 23, 

2003) a portion of Gunbarrel Creek that 

we had proposed as critical habitat for 

the subspecies before the Hayman fire. 

Even prior to the Hayman and 

Schoonover fires, Pague and Granau 

(2000) considered catastrophic fire to be 

a high-priority issue for Douglas County. 

We believe fire has the potential to 

affect the Preble’s meadow jumping 

mouse populations both directly and 

indirectly. The intensity, extent, and 

location of any fire event will likely 

dictate the severity of the impact to the 

Preble’s meadow jumping mouse. 

Catastrophic fire events are, by their 

nature, rare. 

Invasive, noxious plants can encroach 

upon a landscape, displace native plant 

species, form monocultures of 

vegetation, and may negatively affect 

food and cover for the Preble’s meadow 

jumping mouse. The control of noxious 

weeds may entail large-scale removal of 

vegetation and mechanical mowing 

operations, which also may affect the 

Preble’s meadow jumping mouse. The 

tolerance of the Preble’s meadow 

jumping mouse for invasive plant 

species remains poorly understood. 

Leafy spurge (Euphorbia esula) may 

form a monoculture, displacing native 

vegetation and thus reducing available 


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habitat (Selleck et al. 1962; Pague and 

Grunau 2000, p. 1–18). Nonnative 

species including tamarisk (Tamarix 

ramosissima) and Russian olive 

(Elaeagnus angustifolia) may adversely 

affect the Preble’s meadow jumping 

mouse (Garber 1995, p. 16; Pague and 

Grunau 2000, p. 1–18). Existing special 

regulations at 50 CFR 17.40(1) exempt 

take incidental to noxious weed control. 

We instituted this exemption to 

recognize that control of noxious weeds 

is likely to produce long-term benefits to 

native vegetation supportive of the 

Preble’s meadow jumping mouse. 

It remains unknown to what extent 

point and non-point source pollution 

(sewage outfalls, spills, urban or 

agricultural runoff) that degrades water 

quality in potential habitat may affect 

the abundance or survival of the 

Preble’s meadow jumping mouse. 

Likewise, it is unknown whether 

pesticides and herbicides, commonly 

used for agricultural and household 

purposes within the range of the 

Preble’s meadow jumping mouse, pose 

a threat to Preble’s meadow jumping 

mice directly, or through their food 

supply, including possible 

bioaccumulation. 

Human-caused development creates a 

range of additional potential impacts 

(through human presence, noise, 

increased lighting, introduced animals, 

and the degradation of air and water 

quality) that could alter Preble’s 

meadow jumping mouse behavior, 

increase the levels of stress, and 

ultimately contribute to loss of vigor or 

death of individuals, and extirpation of 

populations. Introduced animals 

associated with human development 

may displace, prey upon, or compete 

with the Preble’s meadow jumping 

mouse. Feral cats and house mice were 

common in and adjacent to historical 

capture sites where Preble’s meadow 

jumping mice were no longer found 

(Ryon 1996, p. 26). While no cause and 

effect relationship was documented, the 

Preble’s meadow jumping mouse was 13 

times less likely to be present at sites 

where house mice were found 

(Clippinger 2002, p. 104). We have an 

incomplete understanding of the 

mechanisms by which the breadth of 

human-caused development impacts 

Preble’s meadow jumping mouse 

populations. However, the absence of 

Preble’s meadow jumping mouse 

populations in portions of Colorado 

drainages where riparian habitat 

appears relatively favorable but human 

encroachment is pervasive suggests a 

potential cause-and-effect relationship. 

A combination of factors in addition to 

habitat loss may contribute to local 

extirpations. 

Colorado’s Comprehensive Wildlife 

Conservation Strategy lists ‘‘scarcity’’ as 

a threat to meadow jumping mice that 

may lead to inbreeding depression 

(CDOW 2006, p. 102). Small 

populations can be threatened by 

stochastic, or random, changes in a wild 

population’s demography or genetics 

(Brussard and Gilpin 1989, pp. 37–48; 

Caughley and Gunn 1996, pp. 165–189). 

A stochastic demographic change in 

small populations, such as a skewed age 

or sex ratio (for example, a loss of adult 

females), can negatively affect 

reproduction and increase the chance of 

extirpation. Isolation of populations 

may disrupt gene flow and create 

unpredictable genetic effects that could 

impact Preble’s meadow jumping mouse 

persistence in a given area. While the 

susceptibility of the Preble’s meadow 

jumping mouse to such events has not 

been researched, the documented 

tendency for Preble’s meadow jumping 

mouse populations to vary widely over 

time heightens concern for small and 

isolated populations. The lowest 

population numbers of Preble’s meadow 

jumping mice more accurately reflect 

potential vulnerability than typical or 

average population numbers present. 

Although many trapping efforts have 

targeted Preble’s meadow jumping mice 

in small, isolated reaches of habitat, few 

have documented presence. As noted 

above, we believe populations in 

Colorado would be at higher risk 

because development pressures in this 

portion of the range are more likely to 

result in small, fragmented and 

unsustainable populations. 

The relative ranges, abundance, and 

relationship between the Preble’s 

meadow jumping mouse and the 

western jumping mouse are not yet 

clearly understood, especially in 

Wyoming. Recent confirmation of 

extensive range overlap in Wyoming 

and the apparent predominance of the 

western jumping mouse in some 

southern Wyoming drainages with few 

or no Preble’s meadow jumping mice, 

provide reason for concern. It is 

unknown whether western jumping 

mice are actively competing with 

Preble’s meadow jumping mice, 

affecting Preble’s meadow jumping 

mouse population size and possibly 

limiting distribution, or if this 

distribution patterns is unrelated to 

their interaction. Additional study of 

this issue would be desirable. Although 

questions remain, we do not have 

sufficient information to indicate this is 

a threat to the Preble’s meadow jumping 

mouse in any portion of its range. 

Impacts to the Preble’s meadow 

jumping mouse under predicted future 

climate change are unclear. A trend of 

warming in the mountains of western 

North America is expected to decrease 

snowpack, hasten spring runoff, and 

reduce summer flows 

(Intergovernmental Panel on Climate 

Change 2007, p. 10). Increased summer 

heat may increase the frequency and 

intensity of wildfires (Intergovernmental 

Panel on Climate Change 2007, p. 14). 

Stream-flow reductions or seasonal 

changes in flow due to climate change 

will probably cause a greater disruption 

in watersheds with a high level of 

human development than in those with 

a lower level of development (Hurd et 

al. 1999, p. 1402). The three major river 

basins that support the Preble’s meadow 

jumping mouse have heightened 

vulnerability to the effects of climate 

change due to the degree of human 

development, natural variability in 

stream-flow, ratio of precipitation lost to 

evapotranspiration, and groundwater 

depletion (Hurd et al. 1999, p. 1404). 

Conflicts between human needs for 

water and maintenance of existing 

wetland and riparian habitats will be 

heightened. Therefore, while it appears 

reasonable to assume that Preble’s 

meadow jumping mouse may be 

affected, we lack sufficient certainty to 

know how climate change will affect the 

subspecies. 

Overall, the impacts associated with 

other natural or manmade factors 

affecting the Preble’s meadow jumping 

mouse and the subspecies’ habitat 

remain largely unassessed, and 

therefore, largely unknown. Although 

questions remain regarding these 

factors, we do not have sufficient 

information to indicate that these factors 

are a threat to Preble’s meadow jumping 

mouse long-term conservation status. To 

the extent that meaningful impacts are 

possible, small and fragmented 

populations are likely to be more 

vulnerable. 

Conclusion of the 5-Factor Analysis 

Is the Subspecies Threatened or 

Endangered throughout ‘‘All’’ of its 

Range—As required by the Act, we 

considered the five potential threat 

factors to assess whether the Preble’s 

meadow jumping mouse is threatened 

or endangered throughout all or a 

significant portion of its range. When 

considering the listing status of the 

subspecies, the first step in the analysis 

is to determine whether the subspecies 

is in danger of extinction throughout all 

of its range. If this is the case, then we 

list the subspecies in its entirety. For 

instance, if the threats to a subspecies 

are directly acting on only a portion of 

its range, but they are at such a large 

scale that they place the entire 


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subspecies in danger of extinction, we 

would list the entire subspecies. 

Destruction and modification of 

habitat and the resulting curtailment of 

range is the most significant factor 

affecting the future conservation status 

of the subspecies. Within Wyoming, 

new distributional data and a better 

understanding of threats has altered our 

perception of the subspecies’ status in 

this portion of its range. At the time of 

listing, data confirming the presence of 

the Preble’s meadow jumping mouse 

was available for only a few sites in 

Wyoming. Since listing, additional 

distributional data has verified that the 

subspecies is widespread in the North 

Platte River basin with distribution 

across at least four drainages. Trapping 

efforts to date suggest that the 

subspecies may remain limited in 

number and distribution within the 

Wyoming portion of the South Platte 

River basin. An improved 

understanding of the subspecies’

distribution suggests that historical 

agricultural activities, such as grazing 

and haying, have had a minimal impact 

on the subspecies to date. In short, 

continuation of these long-standing 

activities appears supportive of existing 

Preble’s meadow jumping mouse 

populations. We have no indication 

these agricultural practices are likely to 

change in the foreseeable future in ways 

that would affect the subspecies’ longterm conservation status. A low 

projected human population growth rate 

is predicted for the four Wyoming 

counties occupied by the Preble’s 

meadow jumping mouse, suggesting that 

few development-related threats are 

likely in this portion of the subspecies’

range into foreseeable future. 

Within Colorado, riparian habitat has 

been severely modified or destroyed by 

human activities. With current and 

projected human population increases 

and commensurate increases in urban 

and rural development, road 

construction, and water use, the ongoing 

loss and modification of riparian habitat 

will continue in much of the Preble’s 

meadow jumping mouse Colorado 

range. Even with protection under the 

Act, development in Colorado has 

continued to affect Preble’s meadow 

jumping mouse habitat, both directly 

and indirectly. Much of the Preble’s 

meadow jumping mouse current range 

in Colorado is on private land. In the 

absence of the Act’s protections, most of 

this habitat would be lost or made 

unsuitable within the foreseeable future. 

While appreciable lands in Colorado 

supporting the Preble’s meadow 

jumping mouse are controlled by 

Federal or State agencies, or have been 

set aside as open space by local 

governments, many of these areas also 

are likely to experience habitat 

degradation in the absence of the Act’s 

protections. Some of these areas will 

experience negative indirect effects from 

upstream development. Where 

conservation properties are not 

extensive, the Preble’s meadow jumping 

mouse populations are likely to be 

small, fragmented, and unsustainable. 

Additional recovery efforts are required 

to provide such extensive contiguous 

conservation properties in Colorado. 

In contrast to Wyoming, our improved 

understanding of the subspecies’ range 

in Colorado has not changed our 

conclusion as to the Preble’s meadow 

jumping mouse’s status in this portion 

of the subspecies’ range. As noted 

above, new data have expanded the 

confirmed distribution of the Preble’s 

meadow jumping mouse to include 

additional sites in Boulder, Douglas, El 

Paso, Jefferson, and Larimer Counties. 

Most of the newly discovered sites are 

subject to the same level of threats 

discussed above. Thus, unlike 

Wyoming, recently documented sites in 

Colorado do not meaningfully alter the 

future conservation status of the 

subspecies in this portion of its range. 

Besides ‘‘present or threatened 

destruction, modification, or 

curtailment of its habitat or range,’’ a 

variety of other factors were considered 

including: Overutilization, disease, 

predation, fire, flooding, invasive 

weeds, weed control programs, 

pesticides, herbicides, non-point source 

pollution, secondary impacts associated 

with human-caused development, 

scarcity, the potential for competition 

between the Preble’s meadow jumping 

mouse and the western jumping mouse, 

and the future effects of climate change. 

The threats to the Preble’s meadow 

jumping mouse from these factors are 

generally poorly understood and 

difficult to predict. Although questions 

remain regarding these factors, we do 

not have sufficient information to 

indicate that these factors are a threat to 

the subspecies long-term conservation 

status. To the extent that meaningful 

impacts are possible, these factors are 

likely to be more significant in areas 

where development pressures have or 

are likely to destroy or modify habitat 

resulting in small and fragmented 

populations. Thus, we expect these 

issues could be meaningful as 

cumulative impacts in the Colorado 

portion of subspecies’ range where 

development pressures are high. In 

Wyoming, we expect these factors will 

continue to have only small, localized 

impacts on the subspecies. 

Based on a better understanding of 

distribution and threats, we find that the 

available data do not support the 

conclusion that the Preble’s meadow 

jumping mouse is likely to become 

endangered in the foreseeable future 

throughout ‘‘all’’ of its range. We 

determine this because distributional 

data has verified that the subspecies is 

more widespread in the North Platte 

River basin of Wyoming than previously 

known, and we are not aware of any 

threats that are likely to have significant 

affects on the long-term conservation 

status of populations of Preble’s 

meadow jumping mouse in Wyoming. 

We expect impacts to the Wyoming 

portion of the subspecies’ range to be 

minor with only small and localized 

effects. We believe a lack of present or 

threatened impacts to the Preble’s 

meadow jumping mouse in Wyoming 

suggests that this subspecies is neither 

in danger of extinction, nor likely to 

become endangered within the 

foreseeable future in this portion of its 

range. Threats in the Colorado portions 

of the subspecies’ range, while severe, 

do not place the entire subspecies in 

danger of extinction within the 

foreseeable future. Thus, the Preble’s 

meadow jumping mouse does not merit 

continued listing as threatened 

throughout ‘‘all’’ of its range. 

Is the Subspecies Threatened or 

Endangered in a Significant Portion of 

its Range—Having determined that the 

Preble’s meadow jumping mouse does 

not meet the definition of threatened or 

endangered in all of its range, we must 

next consider whether there are any 

significant portions of the subspecies’

range that are in danger of extinction or 

are likely to become endangered in the 

foreseeable future. On March 16, 2007, 

a formal opinion was issued by the 

Solicitor of the Department of the 

Interior, ‘‘The Meaning of ‘In Danger of 

Extinction Throughout All or a 

Significant Portion of Its Range’’ (U.S. 

Department of the Interior 2007). We 

have summarized our interpretation of 

that opinion and the underlying 

statutory language below. A portion of 

a subspecies’ range is significant if it is 

part of the current range of the 

subspecies and is important to the 

conservation of the subspecies because 

it contributes meaningfully to the 

representation, resiliency, or 

redundancy of the subspecies. The 

contribution must be at a level such that 

its loss would result in a decrease in the 

ability to conserve the subspecies. 

The first step in determining whether 

a subspecies is threatened or 

endangered in a significant portion of its 

range is to identify any portions of the 

range of the subspecies that warrant 

further consideration. The range of a 

subspecies can theoretically be divided 


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into portions in an infinite number of 

ways. However, there is no purpose to 

analyzing portions of the range that are 

not reasonably likely to be both 

significant and either threatened or 

endangered. To identify those portions 

that warrant further consideration, we 

determine whether there is substantial 

information indicating that (1) the 

portions may be significant, and (2) the 

subspecies may be in danger of 

extinction there or likely to become so 

within the foreseeable future. In 

practice, a key part of this analysis is 

whether the threats are geographically 

concentrated in some way. If the threats 

to the subspecies are essentially uniform 

throughout its range, no portion is likely 

to warrant further consideration. 

Moreover, if any concentration of 

threats applies only to portions of the 

range that are unimportant to the 

conservation of the subspecies, such 

portions will not warrant further 

consideration. 

If we identify any portions that 

warrant further consideration, we then 

determine whether in fact the 

subspecies is threatened or endangered 

in any significant portion of its range. 

Depending on the biology of the 

subspecies, its range, and the threats it 

faces, it may be more efficient for the 

Service to address the significance 

question first, or the status question 

first. Thus, if the Service determines 

that a portion of the range is not 

significant, the Service need not 

determine whether the subspecies is 

threatened or endangered there; if the 

Service determines that the subspecies 

is not threatened or endangered in a 

portion of its range, the Service need not 

determine if that portion is significant. 

The terms ‘‘resiliency,’’

‘‘redundancy,’’ and ‘‘representation’’ are 

intended to be indicators of the 

conservation value of portions of the 

range. Resiliency of a subspecies allows 

the subspecies to recover from periodic 

disturbances. A subspecies will likely 

be more resilient if large populations 

exist in high-quality habitat that is 

distributed throughout the range of the 

subspecies in such a way as to capture 

the environmental variability found 

within the range of the subspecies. It is 

likely that the larger size of a population 

will help contribute to the viability of 

the subspecies overall. Thus, a portion 

of the range of a subspecies may make 

a meaningful contribution to the 

resiliency of the subspecies if the area 

is relatively large and contains 

particularly high-quality habitat or if its 

location or characteristics make it less 

susceptible to certain threats than other 

portions of the range. When evaluating 

whether or how a portion of the range 

contributes to resiliency of the 

subspecies, it may help to evaluate the 

historical value of the portion and how 

frequently the portion is used by the 

subspecies. In addition, the portion may 

contribute to resiliency for other 

reasons; for instance, it may contain an 

important concentration of certain types 

of habitat that are necessary for the 

subspecies to carry out its life-history 

functions, such as breeding, feeding, 

migration, dispersal, or wintering. 

Redundancy of populations may be 

needed to provide a margin of safety for 

the subspecies to withstand catastrophic 

events. This concept does not mean that 

any portion that provides redundancy is 

per se a significant portion of the range 

of a subspecies. The idea is to conserve 

enough areas of the range such that 

random perturbations in the system act 

on only a few populations. Therefore, 

we must examine each area based on 

whether that area provides an increment 

of redundancy that is important to the 

conservation of the subspecies. 

Adequate representation ensures that 

the subspecies’ adaptive capabilities are 

conserved. Specifically, we should 

evaluate a portion to see how it 

contributes to the genetic diversity of 

the subspecies. The loss of genetically 

based diversity may substantially 

reduce the ability of the subspecies to 

respond and adapt to future 

environmental changes. A peripheral 

population may contribute meaningfully 

to representation if there is evidence 

that it provides genetic diversity due to 

its location on the margin of the 

subspecies’ habitat requirements. 

Based on the discussion above, we 

readily identified the Colorado portion 

of the current range of the Preble’s 

meadow jumping mouse as warranting 

further consideration to determine if it 

is a significant portion of the range that 

is threatened or endangered. Even with 

the new information confirming the 

extent of the range in Wyoming, the 

range in Colorado still constitutes the 

bulk of the current range, and the 

threats are largely concentrated in that 

portion. 

We had to consider the question of 

how to define the portion of the current 

range that we would consider further. 

We concluded that it was appropriate to 

consider all of the current range in 

Colorado as a single portion of the range 

for the purpose of this analysis. We 

believe the Wyoming/Colorado State 

line is an appropriate delineation for 

separating the populations in the two 

States here because the respective 

threats to the subspecies appear to be 

significantly different in the two states. 

While we could also consider splitting 

the subspecies into significant portions 

of the range based on river basins (i.e., 

only removing protections in the 

drainages of the North Platte River 

basin), we believe this would be more 

difficult to administer with little 

conservation benefit to the species. We 

believe removing protections in the 

Wyoming portion of the South Platte 

River basin (comprised of the Upper 

Lodgepole Creek drainage and portions 

of the Crow Creek and Lone Tree Creek 

drainages) would be of little biological 

consequence. While limited trapping 

data and analysis of museum specimens 

provide evidence of Preble’s meadow 

jumping mouse occurrence in two of 

these drainages, trapping data also 

indicate that the western jumping 

mouse is much more widespread 

suggesting that in these drainages the 

Preble’s meadow jumping mouse may 

simply be uncommon. Thus, given that 

any additional biological benefit to the 

subspecies is likely to be minimal and 

our assertion that the respective threats 

to the Preble’s meadow jumping mouse 

appear to be significantly different in 

the two states we are instead proposing 

State lines as the northern boundary for 

the Colorado significant portions of 

range. We are accepting comments on 

this approach and may consider using 

river basins in a final rule should the 

available data demonstrate such an 

approach is more appropriate. 

Within Colorado, threats to the 

Preble’s meadow jumping mouse are 

comparable between the South Platte 

River basin and Arkansas River basin. 

Similarly, threats to the Preble’s 

meadow jumping mouse are comparable 

north and south of Denver. Because both 

of these possible partitions have a 

comparable status, further division of 

the subspecies’ range between these two 

portions of its range in Colorado is 

unnecessary. 

Another possibility to consider is 

whether smaller units might be 

appropriate. For example, one could 

consider each individual drainage or 

each individual county. Given the best 

scientific and commercial information 

available, we do not believe such 

subdivisions would result in units that 

would each meaningfully contribute to 

the representation, resiliency, or 

redundancy of the subspecies at a level 

such that its loss would result in a 

decrease in the ability to conserve the 

subspecies. In our view, only when 

drainages or counties are aggregated are 

they significant per the above definition. 

The most logical aggregation of 

drainages is basins which are already 

considered above. The most logical 

aggregation of Counties within Colorado 

is a north and south of Denver split 

which is also already considered above. 


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Therefore, further division of the 

subspecies’ range within Colorado is 

either not appropriate or unnecessary. 

To determine whether the Preble’s 

meadow jumping mouse is threatened 

in any significant portion of its range, 

we first consider how the concepts of 

resiliency, representation, and 

redundancy apply to the conservation of 

this particular subspecies. The Preble’s 

Meadow Jumping Mouse Preliminary 

Draft Recovery Plan provides some 

perspective. The Preliminary Draft calls 

for populations across the current range 

of the subspecies and because the 

Preble’s meadow jumping mouse is a 

riparian-associated subspecies, contends 

that river drainages provide an 

appropriate geographic scale and unit 

for addressing their conservation. The 

Preliminary Draft states (Service 2003b, 

p. 20), ‘‘Species well-distributed across 

their historical range are less susceptible 

to extinction and more likely to reach 

recovery than species confined to a 

small portion of their range. Distributing 

populations throughout different 

drainages reduces the risk that a large 

portion of the range-wide population 

will be negatively affected by any 

particular natural or anthropogenic 

event at any one time. Spreading the 

recovery populations across hydrologic 

units throughout the range of the 

subspecies also preserves the greatest 

amount of the remaining genetic 

variation, and may provide some genetic 

security to the range-wide population.’’

In this case, projected losses of habitat 

in Colorado would meaningfully affect 

the representation, resiliency, or 

redundancy of the subspecies, making 

this portion of the range a significant 

portion of the range. The Colorado 

portion of the range includes: 

• Two of the 3 river basins within the 

subspecies’ range, amounting to 

approximately 65 percent of the 

subspecies’ habitat by river-mile and 

total acreage (67 FR 47154, July 17, 

2002); 

• Thirteen (11 for which trapping has 

confirmed presence) of the 19 drainages 

comprising the range of the Preble’s 

meadow jumping mouse (each of which 

should, according to the Preliminary 

Draft Recovery Plan, contain at least one 

population in order to achieve 

representation, resiliency, and 

redundancy) including 3 of the 4 

recommended large populations and 3 

of the 5 recommended medium 

populations (Service 2003b, p. 22); and 

• Genetic material substantially 

unique within the range of the Preble’s 

meadow jumping mouse (King et al. 

2006b, pp. 4336–4347). 

In conclusion, we believe that loss of 

the Preble’s meadow jumping mouse 

within Colorado would result in a 

decrease in the ability to conserve the 

subspecies. We have determined that, 

based on its importance to the 

conservation of the subspecies and 

because it contributes meaningfully to 

Preble’s meadow jumping mouse 

representation, resiliency, or 

redundancy, the Colorado portion of the 

range constitutes a significant portion of 

the subspecies’ range as described in the 

Act. 

If we identify any portions as 

significant, we then determine whether 

in fact the subspecies is threatened or 

endangered in this significant portion of 

its range. This determination involves 

weighing the magnitude and immediacy 

of the threats. In our view, the 

cumulative magnitude of threat within 

Colorado is very high. Immediacy will 

vary geographically across the range. 

Some areas will be subject to imminent 

threats that would, in the absence of the 

Act’s protections, extirpate populations 

in the near future. In other areas, direct 

and indirect impacts, in the absence of 

the Act’s protections, will not result in 

extirpation for some time. Thus, based 

on the best scientific and commercial 

information available, we find that the 

Preble’s meadow jumping mouse is 

likely to become endangered within the 

foreseeable future throughout the 

Colorado portion of its range. 

In conclusion, the best scientific and 

commercial data suggest that the 

Preble’s meadow jumping mouse is not 

likely to become endangered in the 

foreseeable future throughout all of its 

range. We base this conclusion 

primarily on a lack of present or 

threatened impacts to the Preble’s 

meadow jumping mouse or its habitat in 

Wyoming. Threats in the Colorado 

portions of the subspecies’ range, while 

severe, do not place the entire 

subspecies in danger of extinction 

within the foreseeable future. However, 

based on the magnitude of development 

threats and other pressures to the 

populations throughout the Colorado 

portion of the range, and the lack of 

effective regulatory mechanisms in the 

absence of the Act’s protective 

measures, we conclude that the 

significant portion of the subspecies’

range within Colorado continues to 

meet the definition of threatened under 

the Act, and should remain listed. 

Therefore, we propose to amend the 

listing for the Preble’s meadow jumping 

mouse to specify that the subspecies is 

threatened in the Colorado portion of its 

range only. 

Significant Portion of the Range 

Where the Subspecies Is Threatened—

We propose to amend the list to specify 

that the Preble’s meadow jumping 

mouse is threatened in a significant 

portion of its range. Therefore, we must 

describe that portion because it is the 

area where the protections of the Act 

would remain in place. As previously 

stated the range of a species is the 

general area in which the species can be 

found, including migratory corridors, 

seasonal habitats, and habitats used on 

a regular, though not necessarily 

seasonal, basis. 

The scale at which one defines the 

range of a particular species is fact and 

context dependant. In other words, 

whether one defines the range at a 

relatively course or fine scale depends 

on the life history of the species at issue, 

the data available, and the purpose for 

which one is considering range. 

The Preble’s meadow jumping mouse 

is secretive, almost never observed 

without trapping, and relatively rare 

even where present. Confirmed 

occupancy is based almost entirely on 

intensive trapping efforts, requiring 

hundreds of traps set over multiple 

nights. Preble’s meadow jumping mice 

are able to move miles along stream 

corridors over their lifetime (Ryon 1999; 

Shenk and Sivert 1999a), typically 

utilizing riparian (river) corridors. 

Although the subspecies commonly 

uses riparian vegetation immediately 

adjacent to a stream, other features that 

provide habitat for the subspecies 

include seasonal streams (Bakeman 

1997), low moist areas and dry gulches 

(Shenk 2004), agricultural ditches 

(Meaney et al. 2003), and wet meadows 

and seeps near streams (Ryon 1996). 

Given records of confirmed presence 

and patterns of existing riparian habitat, 

we can draw inferences as to what we 

would consider occupied drainages or 

portions of these drainages. 

To date, aside from some earlier work 

from Colorado Department of Wildlife 

and the Colorado Natural Heritage 

Program, the objective of most trapping 

surveys has not been to document the 

limits of occupied habitat in Colorado. 

While much of the Preble’s meadow 

jumping mouse’s distribution is on 

private lands, most trapping surveys on 

private lands have been conducted by 

consultants based on anticipated 

development of the property by 

landowners (in compliance with section 

7 of the Act). This has resulted in far 

more trapping within the expanding 

development corridor than in rural 

lands where no current development is 

planned. Therefore, we have less 

assurance of current presence or 

potential absence of the Preble’s 

meadow jumping mouse in areas east, 

south and west of the development 

corridor. 


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Trapping can only confirm presence, 

not prove absence. At some sites, 

researchers have seen dramatic changes 

in estimated populations from season to 

season and year to year. A single 

trapping effort in any presumed 

occupied site could be unsuccessful if it 

corresponded to times when few or no 

animals are present. There is 

speculation that the Preble’s meadow 

jumping mouse may move in and out of 

areas (individuals have been shown to 

move miles along stream corridors over 

their lifetime). In areas within the range 

of the subspecies, multiple trap efforts 

in a drainage or portions of a drainage 

are needed to provide strong evidence 

that Preble’s meadow jumping mice are 

likely absent. Again, in many areas 

outside the Front Range development 

corridor trapping has been more limited 

and in some areas where presence has 

not been confirmed by trapping, we do 

not believe trapping data is 

determinative of Preble’s presence at 

particular sites, much less whole 

drainages of portions thereof . 

As with other determinations under 

the Act, we do not define the current 

range on the basis of conclusive 

evidence; rather, we use the best 

available data. The purpose of defining 

range (and hence the significant portion 

of the range) is to set the boundaries of 

the protections of the Act. Therefore, 

defining the boundaries too narrowly 

may lead to the failure to protect some 

Preble’s meadow jumping mice. On the 

other hand, drawing the boundaries 

relatively expansively will not lead to 

unnecessary expense on the part of the 

Service or the public because, as 

described in detail below, existing 

guidance on block clearance zones will 

remain in place. Therefore, in the 

context of describing the current range 

for the purpose of defining the scope of 

the listing for the Preble’s meadow 

jumping mouse, we have determined 

that it is appropriate to use a relatively 

coarse scale to capture all of the areas 

where the best available data suggests 

the Preble’s meadow jumping mouse is 

likely to occur. 

The Preliminary Recovery Plan 

suggests maintaining at least one 

recovery population within each 

drainage (to provide resiliency, 

representation, and redundancy) within 

the existing range of the subspecies. The 

Preliminary Recovery Plan, which 

represents the best available science, 

identifies thirteen drainages that 

comprise the area significant to the 

conservation of the subspecies 

including Big Sandy, Big Thompson, 

Bijou, Cache La Poudre, Clear Creek, 

Crow Creek, Fountain Creek Chico, 

Kiowa, Lone-Tree Owl, Middle South 

Platte—Cherry Creek, Saint Vrain, and 

Upper South Platte (as illustrated in 

figure 2). Recognizing that complete 

information is currently lacking that 

would definitively confirm the presence 

of existing Preble’s meadow jumping 

mouse populations and suitable habitat 

in some drainages, these drainages have 

been included in the Preliminary 

Recovery Plan as representative of the 

current range of the subspecies on the 

presumption that at least a small 

population occurs in each. The intent of 

the Preliminary Recovery Plan was to 

preserve populations throughout the 

existing range to maximize the 

preservation of the remaining genetic 

diversity that may be present. 

For convenience in distinguishing 

this boundary on-the-ground we employ 

latitude and longitude coordinates. We 

believe the latitude and longitude 

boundaries below provide an 

appropriate delineation for the 

significant portion of the Preble’s 

meadow jumping mouse range in 

Colorado. These boundaries are 

inclusive of all areas likely to support 

Preble’s meadow jumping mouse 

populations in Colorado. As a result, all 

records confirming Preble’s meadow 

jumping mouse occurrence in Colorado 

are captured within these boundaries. 

We believe that it is highly unlikely that 

there will be discovery of currently 

existing Preble’s meadow jumping 

mouse populations outside these 

boundaries in Colorado. Therefore, we 

believe removing protections outside 

these boundaries would be of little 

biological consequence. Thus, based on 

best available data, we have identified 

the portion of Colorado west of 103 

degrees 40 minutes West, north of 38 

degrees 30 minutes North, and east of 

105 degrees 50 minutes West as the 

significant portion of the range of the 

subspecies (illustrated in figure 2). 

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BILLING CODE 4310–55–C Eastern boundary (103 degrees, 40 

minutes west)—This boundary is 

inclusive of all areas within the current 

survey guidelines (east to a north-south 


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line through Fort Morgan, Morgan 

County) and also includes the eastern 

extent of the Big Sandy drainage 

(designated in the draft of the recovery 

plan). 

Southern Boundary (38 degrees, 30 

minutes north)—This boundary is 

inclusive of all areas within the current 

survey guidelines (south including all of 

El Paso County) and also includes the 

majority of the Fountain Creek and 

Chico Creek drainages (designated in 

the draft of the recovery plan). Habitat 

in the southern portion of El Paso 

County is limited. The small portions of 

the Fountain and Chico drainages that 

fall outside the boundary are outside the 

current survey guidelines and believed 

not to support Preble’s. 

Western boundary (105 degrees 50 

minutes west)—This boundary is 

inclusive of elevations to 7,600 feet 

(2,316 meters) in the Cache La Poudre 

River, Clear Creek and Upper South 

Platte drainages and all portions of the 

Big Thompson and St. Vrain drainages. 

Administrative Processes—As part of 

our management of the subspecies onthe-ground within this significant 

portion of range area, the Service will 

continue to utilize block clearance 

zones to eliminate unnecessary 

processes (e.g., compliance with section 

7 of the Act) while protecting the listed 

species. In designating a block clearance 

zone, the Service eliminates the need for 

individuals or agencies to coordinate 

with the Service prior to conducting 

activities at locations within the Preble’s 

meadow jumping mouse range. The 

establishment of these block clearance 

zones is based on the likely absence of 

the subspecies within the area, and little 

likelihood that any of the area would be 

of importance to the recovery of the 

subspecies. Block clearance zones have 

been approved for the Denver 

metropolitan area (including most of 

Denver County and portions of Adams, 

Arapahoe, Boulder, Broomfield, 

Douglas, and Jefferson Counties) and 

along Monument, Cottonwood, and 

Sand Creeks in the Colorado Springs 

area. While this substantially reduces 

the regulatory burden, should an 

individual Preble’s meadow jumping 

mouse be found in a block-cleared area, 

it would be fully protected under the 

Act. In addition, outside of the block 

clearance zone, but within the SPR, we 

would continue to identify, on a projectby-project basis, whether surveys for the 

Preble’s meadow jumping mouse are 

needed based on whether suitable 

habitat is present within the action area 

of the project. 

We considered excluding block 

clearance zones from the listing as 

outside the current range of the 

subspecies, but we believe that 

approach would be impractical and illadvised. For example, Preble’s meadow 

jumping mouse block clearance zones 

expand on a near annual basis. If a 

revision to the Code of Federal 

Regulations was required to achieve this 

revision, the process would require 

annual proposed and final rules. This 

would be both unwieldy from a 

workload perspective and result in an 

unnecessary delay in reducing our 

regulatory oversight as this process 

typically takes a year to complete. 

Furthermore, the listing backlog (i.e., a 

shortfall of funds that preclude the 

listing of species that are warranted-butprecluded from threatened or 

endangered status and the designation 

of critical habitat) would preclude 

relisting areas even if future information 

suggests the area was removed 

prematurely (unless emergency listing 

was deemed appropriate). This double 

standard as well as the difficult and 

time-consuming nature of the process 

suggests this approach is not realistic, 

not desirable, and inappropriate. As we 

have in the past, the Service will 

consider modification of the current 

block-clearance zones, or the addition of 

new zones, when the available data 

demonstrate such an action is 

appropriate. 

The above discussion relating to 

specifying a significant portion of the 

range of the Preble’s meadow jumping 

mouse as threatened represents our 

current thinking based on the data we 

now have available. However, this is our 

first proposal to specify such a portion 

since issuance of the opinion of the 

Solicitor’s Office on this topic on March 

16, 2007. Thus, we note that we will be 

considering alternative formulations 

and analyses before issuing a final 

determination, and the final 

determination may vary in its 

particulars from this proposed rule. 

We particularly invite data, analyses, 

and other comments regarding the 

following issues: 

(1) What is the current range of the 

Preble’s meadow jumping mouse? In the 

absence of confirmation of presence of 

Preble’s meadow jumping mouse by 

trapping, what information is sufficient 

for the Service to determine that, based 

on the best data available, an area is part 

of the current range of the subspecies? 

(2) On how fine or coarse a scale 

should we define the portion of the 

range that we may specify as both 

significant and threatened? 

Theoretically, the scale could be as 

coarse as the entire state of Colorado, or 

as fine as the scale used in critical 

habitat designations. For the reasons 

discussed above, this proposed rule is 

based on an intermediate scale. 

(3) How should the boundaries of the 

portion of the range at issue be defined? 

By latitude and longitude lines? By 

drainage boundaries? By county lines? 

By reference to particular streams? By 

some other means? 

(4) Is it appropriate to use the 

Colorado/Wyoming border to divide the 

range of the subspecies? If the Preble’s 

meadow jumping mouse in particular 

sites within Colorado (particularly those 

adjacent to the border with Wyoming) 

are not threatened, should they be 

included within the significant portion 

of the range specified as threatened? 

Likewise, if the Preble’s meadow 

jumping mouse in particular sites 

within Wyoming (particularly those 

adjacent to the border with Colorado) 

are threatened, should they be included 

within the significant portion of the 

range specified as threatened? 

(5) If we use a relatively coarse scale 

to define the current range of the 

subspecies, how should we address an 

area within that range if we have 

information suggesting that the 

subspecies does not currently occupy—

or has never actually occupied—that 

particular area within its overall range? 

Should those areas be geographically 

excluded from the significant portion of 

the range specified as threatened? Or are 

those areas best addressed through 

administrative implementation, such as 

the block clearance zones described 

above? What impacts to the subspecies, 

the public, and the Service will result 

from employing each of the possible 

strategies? 

(6) If we determine to define the 

portion of the range specified as 

threatened as excluding areas (at the 

appropriate scale) that the best data 

available suggests are not currently 

occupied by the Preble’s meadow 

jumping mouse, how should we do that? 

Should such areas (for example, parts of 

the Denver metropolitan area) be 

mapped, or excluded by narrative text? 

What sort of boundaries would be 

available for defining such areas as not 

part of the range specified as 

threatened? What purposes would be 

served by adding to the complexity of 

the listing rule? What purposes would 

be served by reducing the complexity of 

the listing rule? 

(7) Is it appropriate to aggregate all of 

the current range of the Preble’s 

meadow jumping mouse in Colorado 

into one portion for the purpose of this 

analysis? If particular sites within 

Colorado are not independently 

significant portions of the range of the 

Preble’s meadow jumping mouse, 

should they still be considered part of 


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the portion of the range that is 

collectively significant? 

Depending on the comments received 

during the public comment period and 

our further analysis of these issues, the 

final determination could incorporate 

any of the possible answers to these 

questions. 

Effects of the Proposed Rule 

If finalized, this action would amend 

the listing for the Preble’s meadow 

jumping mouse by specifying that the 

subspecies is threatened in the Colorado 

portion of its range. This action also 

would eliminate critical habitat (June 

23, 2003, 68 FR 37275) in Wyoming. 

Additionally, the take exemptions of the 

4(d) species rule would no longer be 

necessary, and therefore would no 

longer apply, in Wyoming (May 22, 

2001, 66 FR 28125; October 1, 2002, 67 

FR 61531; May 20, 2004, 69 FR 29101). 

Thus, the prohibitions and conservation 

measures provided by the Act would no 

longer apply to this subspecies in 

Wyoming. Federal agencies would no 

longer be required to consult with us to 

insure that any action they authorize, 

fund, or carry out in Wyoming would 

not likely jeopardize the continued 

existence of the subspecies or result in 

destruction or adversely modify critical 

habitat in Wyoming. However, to the 

extent an activity in Wyoming would 

adversely affect the subspecies or 

critical habitat within its range listed in 

Colorado, consultation under section 7 

would still be required. 

Future Conservation Measures 

No specific preservation or 

management programs exist for the 

Preble’s meadow jumping mouse in 

Wyoming. We believe that sufficient 

habitat will remain in Wyoming over 

the foreseeable future to allow for the 

continued viability of this subspecies. In 

the significant portion of the range 

within Colorado, the Preble’s meadow 

jumping mouse would continue to be 

protected under the Act. 

Peer Review 

In accordance with our peer review 

policy published in the Federal Register 

on July 1, 1994 (59 FR 34270) and the 

Office of Management and Budget’s 

(OMB) Final Information Quality 

Bulletin for Peer Review, we seek the 

expert opinions of appropriate and 

independent specialists regarding this 

proposal. In this case, we will seek the 

comments of two sets of reviewers. 

First, we will contact the same five 

experts invited to provide comments on 

the previous proposed rule (70 FR 5404, 

February 2, 2005; 71 FR 8556, February 

17, 2006; 71 FR 16090, March 30, 2006). 

The selected reviewers were selected for 

their expertise in genetics, systematics, 

and small mammals. We will ask these 

reviewers to review this proposal’s 

taxonomic discussion. Second, we will 

contact an additional five experts to 

review the remainder of this proposal. 

We will select reviewers for expertise in 

small-mammal biology, ripariancommunity ecology and status, 

population dynamics and extinction 

risk, and/or development trends and 

land-use conflicts. The purpose of such 

review is to ensure that we base our 

final decision on scientifically sound 

data, assumptions, and analyses. We 

will send copies of this proposed rule to 

these peer reviewers immediately 

following publication in the Federal 

Register. We will invite these peer 

reviewers to comment, during the 

public comment period, on the specific 

assumptions and conclusions regarding 

our revised proposal. We will consider 

all comments and information received 

during the comment period on this 

proposed rule during preparation of a 

final rulemaking. Accordingly, the final 

decision may differ from this proposed 

rule. 

Clarity of the Rule 

We are required by Executive Orders 

12866 and 12988 and by the 

Presidential Memorandum of June 1, 

1998, to write all rules in plain 

language. This means that each rule we 

publish must: 

(a) Be logically organized; 

(b) Use the active voice to address 

readers directly; 

(c) Use clear language rather than 

jargon; 

(d) Be divided into short sections and 

sentences; and 

(e) Use lists and tables wherever 

possible. 

If you feel that we have not met these 

requirements, send us comments by one 

of the methods listed in the ADDRESSES

section. To better help us revise the 

rule, your comments should be as 

specific as possible. For example, you 

should tell us the numbers of the 

sections or paragraphs that are unclearly 

written, which sections or sentences are 

too long, the sections where you feel 

lists or tables would be useful, etc. 

Energy Supply, Distribution, or Use 

On May 18, 2001, the President issued 

an Executive Order (E.O. 13211; Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use) on regulations that 

significantly affect energy supply, 

distribution, and use. The E.O. 13211 

requires agencies to prepare Statements 

of Energy Effects when undertaking 

certain actions. As this proposed rule is 

not expected to significantly affect 

energy supplies, distribution, or use, 

this action is not a significant energy 

action and no Statement of Energy 

Effects is required. 

Paperwork Reduction Act 

This proposed rule does not contain 

any new collections of information that 

require approval by the Office of 

Management and Budget (OMB) under 

the Paperwork Reduction Act of 1995 

(44 U.S.C. 3501 et seq.). This proposed 

rule will not impose recordkeeping or 

reporting requirements on State or local 

governments, individuals, businesses, or 

organizations. An agency may not 

conduct or sponsor, and a person is not 

required to respond to, a collection of 

information unless it displays a 

currently valid OMB control number. 

National Environmental Policy Act 

The Service has determined that 

Environmental Assessments and 

Environmental Impact Statements, as 

defined under the authority of the 

National Environmental Policy Act of 

1969, need not be prepared in 

connection with regulations adopted 

pursuant to section 4(a) of the Act. We 

published a notice outlining the 

Service’s reasons for this determination 

was published in the Federal Register 

on October 25, 1983 (48 FR 49244). 

References 

A complete list of all references cited 

herein is available upon request from 

the Colorado Field Office (see 

ADDRESSES). 

Author 

The primary authors of this document 

are staff located at the Colorado Field 

Office (see ADDRESSES). 

List of Subjects in 50 CFR Part 17 

Endangered and threatened species, 

Exports, Imports, Reporting and record 

keeping requirements, Transportation. 

Proposed Regulation Promulgation 

Accordingly, we propose to amend 

part 17, subchapter B of chapter I, title 

50 of the Code of Federal Regulations as 

set forth below. 

PART 17—[AMENDED] 

1. The authority citation for part 17 

continues to read as follows: 

Authority: 16 U.S.C. 1361–1407; 16 U.S.C. 

1531–1544; 16 U.S.C. 4201–4245; Pub. L. 99–

625, 100 Stat. 3500; unless otherwise noted. 

2. Amend § 17.11(h) by revising the 

entry for ‘‘Mouse, Preble’s meadow 

jumping’’ under ‘‘MAMMALS’’ in the 


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63024 Federal Register / Vol. 72, No. 215 / Wednesday, November 7, 2007 / Proposed Rules 

List of Endangered and Threatened 

Wildlife to read as follows: 

§ 17.11 Endangered and threatened 

wildlife. 

* * * * * 

(h) * * * 

Species 

Historic range Vertebrate population where 

endangered or threatened Status When listed 

Critical 

habitat 

Special 

rules Common name Scientific name 

Mammals 

* * * * * * * 

Mouse, Preble’s 

meadow jumping.

Zapus hudsonius 

preblei.

U.S.A. (CO, WY) U.S.A., north-central CO (that portion of Colorado west of 103 degrees 40 minutes West, north of 

38 degrees 30 minutes North, 

and east of 105 degrees 50 

minutes West).

T .......... 636 17.95(a) 17.40(l) 

* * * * * * * 

3. Amend § 17.40(l) as follows: 

a. By revising paragraph (l)(2)(vi)(E) to 

read as set forth below; and 

b. By revising paragraph (l)(4) to read 

as set forth below. 

§ 17.40 Special rules—mammals. 

* * * * * 

(l) * * * 

(2) * * * 

(vi) * * * 

(E) Any future revisions to the 

authorities listed in paragraphs 

(l)(2)(vi)(A) through (D) of this section 

that apply to the herbicides proposed 

for use within the species’ range as 

specified in § 17.11(h). 

* * * * * 

(4) Where does this rule apply? The 

take exemptions provided by this rule 

are applicable within the range of the 

Preble’s meadow jumping mouse as 

specified in § 17.11(h). 

* * * * * 

§ 17.95 [Amended] 

4. In § 17.95(a), amend the entry for 

‘‘Preble’s Meadow Jumping Mouse 

(Zapus hudsonius preblei)’’ by removing 

paragraphs (4) through (7), and by 

redesignating paragraphs (8) through 

(13) as (4) through (9), respectively. 

Dated: October 30, 2007. 

H. Dale Hall, 

Director, U.S. Fish and Wildlife Service. 

[FR Doc. 07–5486 Filed 11–1–07; 8:45 am] 

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