# Endangered and Threatened Wildlife and Plants; 12-Month Finding on Two Petitions to Delist the Preble's Meadow Jumping Mouse

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A2013-12387

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** May 24, 2013
- **Citation:** 78 FR 31680

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R6-ES-2012-0095; FXES11130900000-134-FF09E30000]
Endangered and Threatened Wildlife and Plants; 12-Month Finding on Two Petitions to Delist the Preble's Meadow Jumping Mouse

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of 12-month petition finding.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding on two petitions to delist the Preble's meadow jumping mouse (
Zapus hudsonius preblei)
under the Endangered Species Act of 1973, as amended (Act). After review of the best available scientific and commercial information, we find that delisting the Preble's meadow jumping mouse is not warranted at this time. We base our determination on the continued loss and modification of the Preble's meadow jumping mouse's habitat to human development, the inadequacy of existing regulatory mechanisms, and other natural factors, including wildfire and threats associated with global climate change. Although delisting is not warranted at this time, we ask the public to submit to us at any time any new information that becomes available concerning conservation measures or threats to this subspecies or its habitat.

DATES:

The finding announced in this document was made on May 24, 2013.

ADDRESSES:

This finding is available on the Internet at
http://www.regulations.gov
at Docket Number FWS-R6-ES-2012-0095. Supporting documentation we used in preparing this finding is available for public inspection, by appointment, during normal business hours at the U.S. Fish and Wildlife Service, Colorado Field Office at 134 Union Blvd., Suite 670, Lakewood, CO 80228. Please submit any new information, materials, comments, or questions concerning this finding to the above street address.

FOR FURTHER INFORMATION CONTACT:

Susan Linner, Field Supervisor, U.S. Fish and Wildlife Service, Colorado Field Office (see
ADDRESSES
); by telephone at (303) 236-4773; or by facsimile at (303) 236-4005. If you use a telecommunications device for the deaf (TDD), please call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

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

The term “species” is specifically defined as a term of art in the Act to include “subspecies” and, for vertebrate species, “distinct population segments,” in addition to taxonomic species. 16 U.S.C. 1532(16). Therefore, when we use the term “species” in this finding, with or without quotation marks, we generally mean to refer to this statutory usage, which includes species, subspecies, and distinct population segments in general. When referring more specifically to the Preble's meadow jumping mouse (PMJM), we use the term subspecies.

Previous Federal Actions

We listed the PMJM as threatened under the Act on May 13, 1998 (63 FR 26517).

On May 22, 2001, we published a final section 4(d) special rule for the PMJM that prescribed the regulations necessary and advisable to conserve the subspecies. When we establish a special rule for a threatened subspecies, the general regulations for some prohibitions under the Act do not apply and the special rule contains the prohibitions, and exemptions, necessary and advisable to conserve the subspecies. The 4(d) rule for the PMJM applied the prohibitions for threatened animals (50 CFR 17.31) except it allowed “take” for certain rodent control activities, ongoing agricultural activities, maintenance and replacement of existing landscaping, and existing uses of water from May 22, 2001, through May 22, 2004 (66 FR 28125). The Act defines “take” as harass, harm, pursue, hunt, shoot, would, kill, trap, capture, or collect any threatened or endangered species or subspecies. Harm may include significant habitat modification where it kills or injures a listed species by impairing essential behaviors, such as breeding, feeding, or sheltering. Unless allowed by special regulations or a permit, take of a listed animal is unlawful under the ESA. On October 1, 2002, we amended the 4(d) rule for the PMJM to allow take for certain noxious weed control and ditch maintenance activities from October 1, 2002, through May 22, 2004 (67 FR 61531). We made the special rule, as amended, permanent on May 20, 2004 (69 FR 29101).

After listing, we assembled a Preble's meadow jumping mouse Recovery Team (Recovery Team), composed of scientists and stakeholders to develop a plan to recover the subspecies. In June 2003, the PMJM Recovery Team provided their recommendations for the recovery of the PMJM in a draft recovery plan. The Service revised this working draft in November 2003. Although the Recovery Team drafted the Preliminary Draft Recovery Plan in the format of a Recovery Plan, and used the term “Recovery Plan” within the document, the document was not approved as an official draft Recovery Plan. However, this Preliminary Draft Recovery Plan (USFWS 2003b) remains the best source of scientific information available concerning the recovery needs of the PMJM. The Recovery Team intends to reconvene following this finding.

We published a final rule designating critical habitat for the PMJM on June 23, 2003 (68 FR 37276). On December 15, 2010, we published a final rule revising critical habitat for the PMJM in Colorado (75 FR 78430).

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 the PMJM from the Federal List of Endangered and Threatened Wildlife (Freudenthal 2003; Sonnenberg 2003). The petitions maintained that the PMJM should be delisted based on the taxonomic revision suggested by Ramey
et al.
(2003). Additionally, the petitioners alleged that the subspecies was no longer threatened based upon new distribution, abundance, and trend data (Freudenthal 2003, p. 1; Sonnenberg 2003, p. 1).

In response to these petitions, we published a notice in the

Federal

Register

on March 31, 2004 (69 FR 16944), announcing a 90-day finding that the petitions presented substantial information indicating that the petitioned action to delist the subspecies may be warranted and initiating a status review of the subspecies. On February 2, 2005, we published a 12-month finding (70 FR 5404) that the petitioned action was warranted and published a proposed rule to remove the PMJM from the Federal List of Endangered and Threatened Wildlife.

On February 17, 2006, the Service announced (71 FR 8556) that we were extending the rulemaking process an additional 6 months, as allowed under section 4(b)(6)(B)(i) of the Act, in order to rectify the conflicting conclusions of two studies of the PMJM's taxonomy and that we were reopening the comment period on the February 2, 2005, proposed rule. We assembled a panel of experts to carefully review and assess the studies by Ramey
et al.
(2005) and King
et al.
(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 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 PMJM'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)). In addition, the Service agreed that if we did publish a new proposed regulation, we would submit a final determination on that proposed regulation to the
Federal Register
no later than June 30, 2008.

On November 7, 2007, we published a revised proposed rule (72 FR 62992) to amend the listing of the PMJM to specify over what portion of its range the subspecies is threatened.

On July 10, 2008, we published a final rule (73 FR 39790) amending the listing determination that removed the Act's protections for the PMJM in Wyoming. In this rule, we relied on the March 16, 2007, Memorandum Opinion from the Department of the Interior's Office of the Solicitor (Opinion M-37013) to interpret the Act's term “significant portion of the range,” or SPR. Under Opinion M-37013, we determined that the PMJM was not threatened throughout all of its range, but that the portion of its range located in Colorado represented a significant portion of the range where the subspecies should retain its threatened status. Therefore, this SPR determination recognized a difference in status between the Wyoming and Colorado portions of the PMJM's range.

On June 23, 2009, the Center for Native Ecosystems challenged our interpretation of the SPR language as applied to the July 10, 2008, amended PMJM decision in the United States District Court for the District of Colorado. After that lawsuit was filed, two courts vacated listing decisions for two other species that relied on the same statutory interpretation contained in Opinion M-37013. On May 4, 2011, the Solicitor of the Department of the Interior withdrew Opinion M-37013, and the Service announced its intent to propose a joint policy with the National Marine Fisheries Service (NMFS) regarding the interpretation and implementation of the Act's statutory phrase “in danger of extinction throughout all or a significant portion of its range.” In light of these court decisions and the subsequent withdrawal of Opinion M-37013, we filed a motion for voluntary remand and vacatur of the 2008 PMJM amended listing decision. On July 7, 2011, the United States District Court for the District of Colorado granted this motion and ordered the 2008 amended listing decision vacated and remanded as of August 6, 2011 (
Center for Native Ecosystems, et al.
v.
Salazar, et al.,
09-cv-01463-AP-JLK, 2011 U.S. Dist. LEXIS 72664). On August 5, 2011, the Service issued a final rule (76 FR 47490) complying with the court order, which reinstated the Act's regulatory protections for the PMJM in Wyoming on August 6, 2011.

In addition to remanding the amended listing determination, the court ordered that we complete a status review for the PMJM to address the December 23, 2003, delisting petitions submitted by the State of Wyoming and Coloradoans for Water Conservation and Development. The court required that we publish our 12-month finding in the
Federal Register
by June 1, 2013. On November 26, 2012, we announced the initiation of this status review and encouraged all interested parties to submit any new information regarding the PMJM and its threats (77 FR 70410). This finding addresses these petitions.

On December 9, 2011, FWS and the National Marine Fisheries Service published a notice (76 FR 76987) of draft policy to establish a joint interpretation and application of SPR that reflects a permissible reading of the law and its legislative history, and minimizes undesirable policy outcomes, while fulfilling the conservation purposes of the Act. To date, we have not finalized our draft SPR policy.

Species Information

Meadow jumping mice (
Zapus hudsonius
) are small rodents with long tails, large hind feet, and long hind legs. The fur is coarse, shiny, and rusty, yellow-brown in color with black-tipped hairs forming a dark, distinctive stripe on the back (Hansen 2006, p. 10; Fitzgerald
et al.
2011, pp. 188-189). Although body shape and size are similar to other small rodents, such as deer mice (
Peromyscus maniculatus
), meadow jumping mice are distinguished by their unusually long tails and large hind feet (Hansen 2006, pp. 11-13). The sparsely haired tail occupies approximately 60 percent of the total body length (Fitzgerald
et al.
1994, p. 291; Fitzgerald
et al.
2011, p. 188). The large hind feet enable meadow jumping mice to make long leaps, with horizontal distances recorded between 1 to 2 meters (3 to 6 feet) (Hansen 2006, p. 12). After using the hind legs to spring from the ground, meadow jumping mice whip their long tails like a rudder to change the direction of their jump in midair (Hansen 2006, p. 11; Fitzgerald
et al.
2011, p. 191).

Streams and other watercourses with well-developed riparian vegetation, adjacent relatively undisturbed grasslands, and a nearby water source define typical PMJM habitat (Bakeman 1997, pp. 22-31; Fitzgerald
et al.
2011, p. 190; Trainor
et al.
2012, p. 429). PMJM prefer riparian areas featuring multi-storied, horizontal cover with an understory of grasses and forbs (Bakeman 1997, pp. 22-31; Bakeman and Deans 1997, pp. 28-30; Meaney
et al.
1997a, pp. 15-16; Meaney
et al.
1997b, pp. 47-48; Shenk and Eussen 1998, pp. 9-11; Schorr 2001, pp. 23-24; Schorr 2003, p. 18). Willow species (
Salix
spp.) typically dominate the shrub canopy, although other shrub species may occur (Shenk and Eussen 1998, pp. 9-11). High-use areas for the PMJM tend to be close to creeks and are associated with a high percentage of shrubs, grasses, and woody debris (Trainor
et al.
2007, pp. 471-472). The hydrologic regimes that support PMJM's habitat range from large perennial rivers such as the South Platte River to small drainages that are only 1 to 3 meters (m) (3 to 10 feet (ft)) wide (USFWS 2013). The PMJM is likely an Ice Age (Pleistocene) relict; once the glaciers receded from the Front Range of Colorado and the foothills of Wyoming

and the climate became drier, the PMJM was confined to riparian systems where moisture was more plentiful (Fitzgerald
et al.
1994, p. 194; Meaney
et al.
2003, p. 611; Smith
et al.
2004, p. 293; Fitzgerald
et al.
2011, p. 189).

Meadow jumping mice are primarily nocturnal or crepuscular (active during twilight), but may also be active during the day (Whitaker 1963, p. 231; Fitzgerald
et al.
2011, p. 191). During the day, mice rest within day nests that they weave from grasses (Hansen 2006, p. 136; Fitzgerald
et al.
2011, p. 191). Although lush, riparian vegetation near water is the PMJM's primary habitat, mice venture into bordering uplands, 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; USFWS 2003b, p. 26). During the winter, the PMJM hibernates, remaining underground longer than most hibernating mammals (Whitaker 1963, p. 232; Hansen 2006, p. 15). PMJMs typically enter their underground hibernacula to hibernate in late September or early October and emerge the following May (Whitaker 1963, p. 232; Meaney
et al.
2003, pp. 618, 621; Fitzgerald
et al.
2011, p. 191).

Radio telemetry and mark-recapture data provide insight into the PMJM's home ranges and dispersal capabilities. At Plum Creek in Douglas County, Colorado, the PMJM's home ranges averaged 0.50 hectares (ha) (1.24 acres (ac)) based on radio-telemetry (Trainor
et al.
2012, p. 432). In the Pike National Forest of Colorado, travel distances averaged 413.9 m with an approximate home range size of 1.02 ac (Hansen 2006, p. 158). At the Air Force Academy in El Paso County, Colorado, home ranges were between 0.17 to 3.84 ha (0.42 to 9.49 ac), with an average home range of 1.41 ha (3.48 ac) (Schorr 2003, p. 9). During this study, the farthest distance moved by individual PMJMs ranged from 43 to 3,176 ft (13 to 968 m), with an average maximum travel distance of 1,188 ft (362 m) (Schorr 2003, p. 9). An earlier study documented a PMJM moving as far as 1.1 kilometers (km) (0.7 mile (mi)) in 24 hours (Ryon 1999, p. 12). However, compared to radio telemetry data, mark-recapture data suggest that the PMJM may have longer dispersal capabilities. Mark-recapture data between active seasons identified mice traveling more than 4 km (2.3 mi) along a linear riparian system (Schorr 2003, p. 10; Schorr 2012, pp. 1274, 1278).

For additional information on the biology of this subspecies, please reference our May 13, 1998, final rule to list the PMJM as threatened (63 FR 26517) and the October 8, 2009, proposed rule to revise the designation of critical habitat for the PMJM (74 FR 52066).

Taxonomy

The PMJM is a member of the family Dipodidae (jumping mice) (Wilson and Reeder 1993, p. 499), which contains four extant genera, or living family members. Two of these genera,
Zapus
(jumping mice) and
Napaeozapus
(woodland jumping mice), are found in North America (Hall 1981, p. 841; Wilson and Ruff 1999, pp. 665-667).

Below we summarize and evaluate the scientific studies regarding PMJM's taxonomy.

Pre-Listing Taxonomic Information

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. h. campestris.
Cockrum and Baker (1950, pp. 1-4) later designated specimens from Nebraska, Kansas, and Missouri as a separate subspecies,
Z. h. pallidus.

After studying the morphological (physical form and structure) characteristics of 3,600 specimens, Krutzsch revised the taxonomy of the
Zapus
genus (1954, pp. 352-355). His 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 genus included 11 subspecies distributed across North America.

Krutzsch (1954, pp. 452-453) further refined the taxonomy of
Zapus
by describing and naming the subspecies the Preble's meadow jumping mouse (
Zapus hudsonius preblei
) based on geographic separation and morphological differences from other subspecies. 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 PMJM, 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) examined the morphometric characteristics of four adult and seven non-adult specimens. Krutzsch (1954, pp. 452-453) reported seven distinguishing traits, but only published quantitative results (nine measurements) on two of these traits for three specimens (Krutzsch 1954, p. 465). Acknowledging the small number of samples upon which his conclusion was based, Krutzsch (1954, p. 453) nonetheless concluded that the differences between PMJMs and neighboring meadow jumping mice was considerable and enough to warrant a subspecific designation.

In Krutzsch's analysis, subspecies neighboring the PMJM included
Z. h. campestris
in northeastern 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). In 1981, Hafner
et al.
(1981, p. 501) identified the New Mexico jumping mouse (
Z. h. luteus)
from Arizona and New Mexico as another neighboring subspecies of meadow jumping mouse. Scientists previously assumed that these Arizona and New Mexico populations were subspecies of western jumping mice, not meadow jumping mice (Krutzsch 1954, pp. 406-407; Hall and Kelson 1959, pp. 774-776; Jones 1981, p. iv). Among recognized subspecies, Krutzsch (1954, p. 452) found that the PMJM most closely resembled
Z. h. campestris
from northeastern Wyoming, but documented differences in coloration and skull characteristics.

Krutzsch's description (1954), as modified by Hafner
et al.
(1981, p. 501), with 12 subspecies of meadow jumping mice in North America, has been 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 his 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 PMJM specimens. Jones' dissertation (1981, p. 144) concluded that the Pacific jumping mouse was not

a valid taxon and suggested reducing the number of species in the
Zapus
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 PMJM, Jones (1981, pp. 288-289) wrote, “No named subspecies is geographically restricted by a barrier, with the possible exception of
Zapus hudsonius 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' taxonomic conclusions regarding the PMJM are questionable, as he did not compare the subspecies to
Z. h. campestris,
the closest neighboring subspecies, nor did he conduct statistical tests of morphological differences between the PMJM and any other subspecies (1981, p. 144). Regardless, Jones' doctoral committee approved his dissertation in 1981, but Jones did not publish his research in a peer-reviewed journal (Jones 1981, p. ii). Thus, Jones' findings were not incorporated into the formal taxonomy for jumping mice.

Prior to our 1998 listing, the Colorado Division of Wildlife (now Colorado Parks and Wildlife (CPW)) funded a genetic analysis of the PMJM (Riggs
et al.
1997). This analysis examined 433 base-pairs in one region of the mitochondrial deoxyribonucleic acid (mtDNA) (maternally inherited genetic material) across five subspecies of meadow jumping mouse (92 specimens) (Riggs
et al.
1997, p. 1). The study concluded that the PMJM 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 supporting data for this report remain privately held (Ramey
et al.
2003, p. 3). The Riggs
et al.
(1997) results were not published in a peer-reviewed journal, but were peer reviewed by Hafner. Prior to listing, this study was the only available information concerning the genetic uniqueness of the PMJM relative to neighboring subspecies, as Krutzsch's original subspecific designation relied on morphological characteristics and geographic isolation.

Our original listing determined that Krutzsch's (1954) revision of the meadow jumping mouse species, including the description of the PMJM subspecies, was widely supported by the scientific community as evidenced 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 of the Interior and the scientific community concerning the relevant taxonomic group (50 CFR 424.11).

Taxonomic Information Solicited After Listing

In 2003, the Service, the State of Wyoming, and the Denver Museum of Nature and Science funded a study to resolve ongoing questions about the taxonomic relationship between the PMJM and neighboring meadow jumping mice (USFWS 2003a, pp. 1-2). In December 2003, we received a draft report from the Denver Museum of Nature and Science examining the uniqueness of the PMJM relative to other nearby subspecies of meadow jumping mice (Ramey
et al.
2003). In 2004, the Service and other partner agencies provided additional funding to expand the scope of the original study (USFWS 2004). In August 2005, the journal
Animal Conservation
published an expanded version of this original report (Ramey
et al.
2005). This publication included an examination of morphometric differences, mtDNA, and microsatellite DNA (a short, noncoding DNA sequence 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 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 nine skull measurements of 40 PMJMs, 40
Zapus hudsonius 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 PMJM 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.

Additionally, Ramey
et al.
examined 346 base-pairs in one region of the mtDNA across five 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 PMJM and neighboring subspecies. The subspecies failed Ramey
et al.'
s tests of uniqueness in that the subspecies did not show greater molecular variance among than within subspecies or did not demonstrate nearly complete reciprocal monophyly (genetic similarity) with respect to other subspecies. The data demonstrated that all of the mtDNA haplotypes (alternate forms of a particular DNA sequence or gene) found in the PMJM were also found in
Zapus hudsonius campestris.
The mtDNA data produced by the researchers demonstrated evidence of recent gene flow between the PMJM and neighboring subspecies (Ramey
et al.
2005, p. 338).

Additionally, Ramey
et al.
(2005, pp. 333-334, 338) analyzed five microsatellite loci across five subspecies of meadow jumping mice (195 specimens). During these tests, the subspecies failed Ramey
et al.'
s uniqueness criteria: The subspecies did not show greater molecular variance between than within subspecies and that multiple private alleles were not at a higher frequency than shared alleles at the majority of loci (Ramey
et al.
2005, p. 333). Ramey
et al.
(2005, p. 340) concluded that these results were consistent with their morphometric and mtDNA results.

Finally, Ramey
et al.'s
review of the literature found no published evidence of adaptive or ecological differences between the PMJM and other subspecies of jumping mouse. Therefore, Ramey
et al.
(2005, pp. 339-341) concluded that the lack of morphological difference supported the proposition of no adaptive or ecological difference between the subspecies.

To summarize, based on hypothesis testing using four lines of evidence (morphometrics, mtDNA, microsatellites, and a lack of recognized adaptive differences), Ramey
et al.
concluded that the PMJM and
Zapus hudsonius intermedius
should be synonymized with
Z. h. campestris
(2005, p. 340).

Prior to the publication of Ramey
et al.
(2005) in
Animal Conservation,
the CPW and the Service solicited 16 peer reviews of the 2004 draft report provided to the Service (Ramey
et al.
2004a). Fourteen reviewers provided comments (Armstrong 2004; Ashley 2004; Bradley 2004; Conner 2004; Crandall 2004; Douglas 2004; Hafner

2004; Meaney 2004; Mitton 2004; Oyler-McCance 2004; Riddle 2004; Sites 2004; Waits 2004; White 2004). In 2005, the Service approached the same 16 experts to review Ramey
et al.
2004b (an expansion of Ramey
et al.
2004a). Eleven of these reviewers provided comments (Ashley 2005; Baker and Larsen 2005; Bradley 2005; Crandall 2005; Douglas 2005; Hafner 2005; Maldonado 2005; Mitton 2005; Oyler-McCance 2005; Waits 2005; White 2005). In 2006, some of these reviewers provided comments on Ramey
et al.
(2005) as part of their review of King
et al.
(2006a). Krutzsch (2004) also reviewed Ramey
et al.
(2004a). 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).

Many of the reviewers generally supported the findings of Ramey
et al.
(Baker and Larsen 2005; Bradley 2004, 2005; Crandall 2004, 2005; Hafner 2004; Krutzsch 2004; Maldonado 2005; Meaney 2004; Mitton 2004, 2005; Riddle 2004; Sites 2004; Waits 2004, 2005). However, the reviewers raised a number of important issues. Because these experts reviewed the unpublished reports (Ramey
et al.
2004a, 2004b), many of the criticisms were addressed prior to publication in
Animal Conservation
(Ramey
et al.
2005). For example, reviewers recommended that the study be augmented to include microsatellite data; this information was added to the published version (Ramey
et al.
2005). Some of the most significant unresolved issues identified included:

(1) Reliance upon museum specimens, which can be prone to contamination (Douglas 2004, 2005, 2006; Hafner 2006; Maldonado 2005);

(2) The reliability of, and failure to validate, specimens' museum identification tag (Ashley 2005; Douglas 2004, 2005; Hafner 2004; Oyler-McCance 2004, 2005, 2006);

(3) The sampling regime and its impact on the analysis (Ashley 2006; Crandall 2006a; Douglas 2006; Hafner 2006; Maldonado 2005, 2006; Oyler-McCance 2004, 2006);

(4) Reliance upon a small portion (346 base-pairs) of mtDNA (Ashley 2004, 2005; Baker and Larsen 2005; Crandall 2004, 2005, 2006a; Douglas 2004, 2005, 2006; Hafner 2005, 2006; Maldonado 2005; Oyler-McCance 2004, 2005, 2006; Riddle 2004; Sites 2004; Waits 2004, 2005);

(5) The small number of microsatellite DNA loci examined (five) (Crandall 2006a; Oyler-McCance 2006; Hafner 2006; Vignieri
et al.
2006, p. 241);

(6) The statistical tests employed (Crandall 2004; Douglas 2004, 2005; Hafner 2006; Maldonado 2005; Mitton 2005; Oyler-McCance 2005, 2006);

(7) 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, 2006; Hafner 2005, 2006; Oyler-McCance 2004, 2005; Vignieri
et al.
2006, pp. 241-242; White 2004);

(8) Whether the western jumping mouse was an appropriate outgroup (a closely related group that is used as a rooting point of a phylogenetic tree) (Douglas 2004);

(9) Failure to measure all of the morphological traits examined by Krutzsch (1954) (Vignieri
et al.
2006, p. 238); and

(10) An inadequate evaluation of ecological exchangeability and habitat differences among subspecies (Ashley 2004; Conner 2004; Douglas 2004; Meaney 2004; Mitton 2004; Oyler-McCance 2004, 2005; Sites 2004; Vignieri
et al.
2006, p. 238; Waits 2004, 2005).

Collectively, these critiques indicated that delisting the PMJM based on the conclusions of Ramey
et al.
alone might be premature.

Post-Listing Taxonomic Scientific Debate

Because our February 2, 2005, proposed rule (70 FR 5404) to delist the PMJM relied solely upon an unpublished report (Ramey
et al.
2004a) that had received mixed peer reviews as described above, verifying these results was a high priority for the Service (Morgenweck 2005; Williams 2004). Thus, the Service contracted with the U.S, Geological Survey (USGS) to conduct an independent genetic analysis of several meadow jumping mouse subspecies (USGS 2005, pp. 1-4). Contrary to Ramey
et al.'
s conclusion, the USGS study concluded that the PMJM should not be synonymized with neighboring subspecies (King
et al.
2006a, pp. 2, 29). The journal
Molecular Ecology
published an expanded version of this report (King
et al.
2006b). This study included an examination of microsatellite DNA, two regions of mtDNA, and 15 specimens critical to the conclusions of Ramey
et al.
(2005).

The USGS study analyzed more genetic material than Ramey
et al.
(2005). King
et al.'
s (2006b, p. 4336) microsatellite analysis examined approximately 4 times the number of microsatellite loci (21) and more than 1.75 times more specimens (348 specimens) than Ramey
et al.
(2005) across the same five 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 PMJM 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 two regions (374 control region and 1,006 cytochrome-B region base-pairs) and more than 1.5 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 five 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, King
et al.'
s mtDNA results indicated that the PMJM did not share haplotypes with any neighboring subspecies (King
et al.
2006b, p. 4341). Such haplotype sharing contributed to Ramey
et al.'
s (2004a, pp. 1, 9; 2005, p. 335) conclusion that the PMJM was not unique and that the PMJM was a less genetically variable population of
Zapus hudsonius campestris.
Because of these conflicting results, King
et al.
(2006b, pp. 4355-4357) reexamined 15 specimens from the University of Kansas Museum collection that were key in Ramey
et al.'
s determination that neighboring subspecies shared haplotypes. King
et al.
(2006b, p. 4357) could not duplicate the mtDNA sequences reported by Ramey
et al.
for these specimens. If these specimens were removed from the analysis, neither study would illustrate haplotype sharing between the PMJM and neighboring subspecies. Therefore, 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)” that “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. Ramey
et al.
(2007, pp. 3519-3520) proposed a number of alternative explanations for these contradictory results including: Nuclear paralogs, or copies of mtDNA sequence that have been incorporated into the nuclear genome and are now pseudogenes, or non-functional genes;

heteroplasmy, or the existence of more than one mitochondrial type in the cells of an individual; different amplification primers and conditions between the studies; and template quality.

Overall, King
et al.
(2006b, p. 19) concluded that considerable genetic differentiation occurred among all five subspecies and found no evidence to support the proposal to synonymize the PMJM,
Zapus hudsonius campestris,
and
Z. h. intermedius.

Prior to its release, King
et al.
(2006a) underwent an internal peer review per USGS policy (USGS 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). Ramey
et al.
(2006b, 2007) also critiqued King
et al.
(2006a, 2006b).

Most of the reviewers supported the findings of King
et al.
(Armstrong 2006; Ashley 2006; Douglas 2006; Hafner 2006; Maldonado 2006; Oyler-McCance 2006; Riddle 2006). These reviews offered a number of issues and possible explanations why King
et al.'
s results differed from those of Ramey
et al.
Because reviewers were asked to review King
et al.'
s unpublished report (King
et al.
2006a), some of their comments were addressed by the authors in their
Molecular Ecology
publication (King
et al.
2006b). For example, numerous reviews suggested expanding the geographic range of the study by adding a PMJM population in Wyoming; this issue was addressed in the published version (King
et al.
2006b). Similarly, the
Molecular Ecology
publication incorporated the suggestion to retest the museum specimens Ramey
et al.
(2005) identified as having shared haplotypes for signs of cross contamination. Other issues raised by the reviewers of the King
et al.
study included:

(1) The sampling regime and its impact on the analysis (Armstrong 2006; Ashley 2006; Crandall 2006a; Douglas 2006; Oyler-McCance 2006; Ramey
et al.
2007, p. 3519; Riddle 2006);

(2) Failure to evaluate morphometrics and ecological exchangeability (Crandall 2006a);

(3) Reliance upon a small portion of control region mtDNA (Riddle 2006);

(4) The number of loci examined (
i.e.,
too many), the programs used to analyze the data, and the resulting sensitivity in detecting difference (Crandall 2006a; Ramey
et al.
2006b; Ramey
et al.
2007, p. 3519);

(5) A specimen collection methodology that could cause contamination (Ramey
et al.
2007, p. 3519);

(6) The statistical tests employed (Crandall 2006a; Douglas 2006; Maldonado 2006; Riddle 2006); and

(7) 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 a scientific review to analyze, assess, and weigh the reasons why the data, findings, and conclusions of the two studies differed (USFWS 2006, p. 14). Following an open and competitive bid process, we selected the Sustainable Ecosystems Institute (SEI) as the contractor (USFWS 2006).

SEI assembled a panel of genetic and systematics experts (SEI 2006a, pp. 7, 56-82). The panelists reviewed, discussed, and evaluated all of the literature relevant to PMJM's taxonomy, including published literature, unpublished reports, third-party critiques, public comments, 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 its 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). 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. Below, we briefly summarize the panel's findings (SEI 2006a).

Morphology:
The panel found that all seven of the morphological characters examined by Krutzsch (1954, pp. 452-453) should have been reexamined in order to support Ramey
et al.'s
proposed taxonomic revision. The panel also concluded that the type specimen (the original specimen from which the description of a new species is made) 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 PMJM had been conducted to support the synonymy of the PMJM 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 PMJM 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.
and that the supporting data for the samples in question were of poor quality and/or quantity (SEI 2006a, pp. 23-32). The panel concluded that no reliable evidence existed of any haplotype sharing between the PMJM and neighboring subspecies (SEI 2006a, p. 42). The panel determined that if the 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 western jumping mice as their outgroup, an unrooted analysis (an analysis without these genetic points of reference or any ancestral assumptions) showed clearer phylogenetic structuring between the subspecies (SEI 2006a, p. 42).

Microsatellite DNA:
The panel found that the two microsatellite datasets contained similar information. The panel pointed out that both the Ramey
et al.
(2005) and King
et al.
(2006b) 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 PMJM, 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 corroborated the distinctness of the PMJM (SEI 2006a, pp. 43).

The panel's overall conclusion was that the available data are broadly consistent with the current taxonomic status of the PMJM 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 approach and conclusions of the SEI report. Some of the most significant issues raised included:

(1) Objection to the deference given to Krutzsch (1954);

(2) Disagreement with the suggestion that all seven morphometric characters examined by Krutzsch (1954) and the type specimen should be reexamined;

(3) Dispute with the assertion that Ramey
et al.'s
(2005) evaluation of ecological significance was inadequate;

(4) Dispute with the contention that the PMJM and neighboring subspecies remain weakly genetically differentiated; and

(5) Objection to SEI's failure to develop objective standards for testing the validity of suspect subspecies.

However, no new data or analyses were presented in this statement, and the panel previously considered most of these 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.
(2007), Crandall and Marshall (2006), Spencer (2006b), and Cronin (2007).

Taxonomic Conclusions

When listed in 1998, the scientific community widely recognized the PMJM as a valid subspecies (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 PMJM (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). We rely on the best available science in listing decisions. Such considerations influenced our February 2, 2005, proposal (70 FR 5404) to delist the PMJM based upon information that questioned the subspecies' taxonomic validity.

At the time of our 2008 final rule (73 FR 39790), the best available information supported the conclusion that the PMJM is a valid subspecies. For this status review, we extensively reviewed all of the scientific data and again determined that the best scientific and commercial data available support the conclusion that the PMJM is a valid subspecies. Specifically, the PMJM's geographic isolation from other subspecies of meadow jumping mice (Krutzsch 1954, pp. 452-453; Long 1965, pp. 664-665; Beauvais 2001, p. 6; Beauvais 2004; SEI 2006a, p. 34; Fitzgerald
et al.
2011, p. 190) 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 PMJM 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; WGFD 2012, pp. 1, 3). In reaching this conclusion, we have not presumed that we must rely on the established taxonomy in the absence of contradictory data (see SEI report at p. 39). Rather, the best scientific and commercial information currently available indicates that the PMJM is a valid subspecies. Therefore, the taxonomic revision for the PMJM proposed by the petitioners in 2003 and suggested in our proposed delisting rule (70 FR 5404, February 2, 2005) is unfounded, and we recognize the PMJM as a valid subspecies and listable entity under the Act. This determination is consistent with our 2008 determination.

We are aware of two ongoing research studies using genetics to address taxonomic or evolutionary questions regarding the PMJM. One study seeks to clarify genetic relationships between meadow jumping mice across North America (Malaney 2013, p. 1). The second study seeks to analyze genetic relationships between PMJM populations in Colorado (Schorr and Oyler-McCance 2012, p. 1). We will evaluate any new information as it becomes available for the PMJM.

Historical Range and Recently Documented Distribution

The PMJM's current range includes portions of the North Platte, the South Platte, and the Arkansas River basins in Colorado and Wyoming (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; Fitzgerald
et al.
2011, p. 189).

When listed in 1998, we used the available trapping information and historic records to approximate the subspecies' historical range. We described the historical range of the PMJM in Wyoming to include five counties (Albany, Laramie, Platte, Goshen, and Converse), but cited only two locations with recent reports of jumping mice likely to be the PMJM. Additionally, we cited a report that suggested that the subspecies might be extirpated (extinct locally) in Wyoming or highly restricted to isolated patches of suitable habitat based on a lack of known captures in over 40 years (Compton and Hugie 1993b, p. 6). At that time, the Wyoming Game and Fish Department (WGFD) also provided comments that the PMJM had likely been extirpated from most or all of its historical range in Wyoming due to the loss and degradation of riparian habitat (Wichers 1997, p. 1). The reports indicated that there were no known populations in Wyoming (Compton and Hugie 1993b, p. 6). Therefore, the best available information at the time of listing influenced our assumption that most of the subspecies' current range occurred in Colorado. The final 1998 listing rule presumed a historical range in Colorado that included portions of 10 counties (Adams, Arapahoe, Boulder, Denver, Douglas, El Paso, Elbert, Jefferson, Larimer, and Weld). The rule also cited recent documentation of the subspecies within only 7 of these 10 counties (Boulder, Douglas, El Paso, Elbert, Jefferson, Larimer, and Weld).

After listing in 1998, trapping studies increased, greatly improving our knowledge of the PMJM's distribution within this presumed historical range. More than 1,650 trapping studies in Colorado and 1,280 records in Wyoming collected over the last 15 years documented the PMJM's presence or likely absence within riparian or adjacent upland habitat (Bowe and Beauvais 2012, p. 11; USFWS 2013). Trapping studies revealed that the PMJM still occurs in both Wyoming and Colorado, although the PMJM's distribution is limited to suitable patches of riparian habitat. Additionally, the lack of captures around human development despite large trapping efforts revealed that the PMJM was likely extirpated from dense, urban areas.

While many trapping efforts targeted locations with no record of historical surveys, most surveys occurred within the presumed historical range of the PMJM or in adjacent drainages with apparently suitable habitat. Over time,

more trapping efforts identified more sites with PMJMs and improved our understanding of the PMJM's range. However, the increase in positive captures, or known occupancy data, merely reflects the increased trapping effort, not a change in the PMJM's range. In other words, while more trapping improved our understanding of the PMJM's distribution, the data did not contract or expand the presumed range of the subspecies. The trapping data refine our understanding of the PMJM's current distribution and presumed response to habitat changes. Additionally, although we have an improved understanding of the PMJM's current range, the resulting occupancy data are not long-term studies, and so provide limited insight into population sizes or trends (Beauvais 2008, p. 2). However, the low capture rates for PMJM throughout its current range, despite extensive trapping efforts in suitable habitats, suggests that population sizes may be low.

In southeastern Wyoming, trapping studies conducted after 1998 identified many additional sites occupied by jumping mice, whether genetically or morphometrically confirmed as PMJMs or western jumping mice, or left unidentified to species. Recent captures and confirmed identifications compiled by the Wyoming Natural Diversity Database (WYNDD) improved our knowledge of the distribution of the PMJM in Wyoming. Trapping studies identified 31 plains, foothills, and montane sites occupied by the PMJM in Wyoming (Bowe and Beauvais 2012, pp. 8, 16). These new data reveal that the PMJM occurs in only four of the five Wyoming counties that we originally described as the likely historical range at the time of listing. The four counties of occupancy in Wyoming are Albany, Laramie, Platte, and Converse Counties. While generalized range maps (Long 1965, p. 665; Armstrong 1972, pp. 248-249; Clark and Stromberg 1987, p. 184) historically depicted the PMJM's range extending east into Goshen County, the new data indicate that the subspecies does not occupy Goshen County (Bowe and Beauvais 2012, pp. 8, 16; Mead 2012, p. 1). This new information does not signify a real, biological contraction of the PMJM's range, but rather reflects our improved understanding of the PMJM's historical and current range in Wyoming.

WYNDD provides the most current data regarding the distribution of the PMJM in Wyoming (Bowe and Beauvais 2012, p. 8). They refute the previously reported presence of the PMJM west of the Laramie Mountains in the North Platte River basin and in the Upper Laramie River drainage in Albany County, as described in our July 10, 2008, final rule (73 FR 39813; Bowe and Beauvais 2012, p. 8). In 2008, we assumed that occurrence of PMJM populations west of the Laramie Mountains and in the Upper Laramie River drainage in Albany County would represent a significant expansion of the formerly known range of the PMJM in Wyoming. However, WYNDD's new data refute previous speculation that the range of the PMJM extends into the Upper Laramie River, Little Laramie River, Rock Creek, and possibly the Medicine Bow River (Smith
et al.
2004, p. 12; Bowe and Beauvais 2012, p. 8). WYNDD's report concludes that no confirmed, likely, or possible records of the meadow jumping mouse fall west of the crest of the Laramie Mountains (Bowe and Beauvais 2012, p. 8).

Specifically, genetic analysis revealed that a jumping mouse from Hutton National Wildlife Refuge in Albany County, Wyoming, previously thought to be a PMJM, was a western jumping mouse (Ramey
et al.
2005, Appendix 3). Additionally, non-genetic analysis suggested that the purported PMJM caught on private land north of Laramie was a western jumping mouse (Beauvais 2012). The elevation of capture, body size, and abundance suggest that jumping mice captured in 2011 and 2012, in the Elk Mountains, at the Little Laramie River, the Rock Creek-Rock River area, and the Upper Medicine Bow River, were potentially western jumping mice, not the PMJM (Beauvais 2012; Bowe and Beauvais 2012, p. 8). Although genetic analysis is required for definitive identification, the new data suggest that the PMJM is not as widely distributed in Wyoming as previously assumed. Genetic results for these captures are pending. Additionally, a lack of meadow jumping mouse captures in the Niobrara, Cheyenne, and Upper Powder River Basins suggests very little connectivity between the PMJM in southeastern Wyoming and
Zapus hudsonius campestris
in northern Wyoming (Bowe and Beauvais 2012, p. 8). These new data improve our understanding of the PMJM's range in Wyoming and clarify previous speculation. Because genetics have now correctly identified previously captured meadow jumping mice, the data do not represent an actual biological contraction of the PMJM's range in Wyoming.

At the time of listing, we discussed how increased trapping efforts in Colorado had recently documented the PMJM's distribution in Elbert, Larimer, and Weld Counties. We also suggested other sites where trapping should occur to determine if the PMJM was present. Additional trapping since the time of listing has expanded the documented distribution of the PMJM in Colorado to include: (1) Additional foothill and montane sites along the Front Range in Larimer, Boulder, Jefferson, and Douglas Counties; (2) previously untrapped, rural, prairie and foothill streams in southern Douglas County and adjacent portions of Elbert County; and (3) additional prairie and foothill streams in northwestern El Paso County. Although we have identified many additional sites in Colorado occupied by the PMJM since the original listing, approximately 70 percent of trapping efforts in Colorado and Wyoming that targeted the PMJM failed to capture jumping mice (USFWS 2013, p. 2). These numerous negative trapping results, even with extensive trapping efforts in suitable habitats, suggest that the subspecies is rare or extirpated from many portions of the subspecies' historical range. Under Factor A in our five-factor threats analysis, we discuss geographic areas where the PMJM may be extirpated.

BILLING CODE 4310-55-P
Figure 1—Map of PMJM's current range based on trapping efforts.

EP24MY13.007

To summarize, the PMJM was previously assumed extirpated from Wyoming at the time of listing, but is now documented in portions of Albany, Laramie, Platte, and Converse Counties, Wyoming (Bowe and Beauvais 2012, p. 8). In Colorado, the PMJM was assumed to occupy 10 counties at the time of listing, but now occupies portions of 7 counties including: Boulder, Douglas, El Paso, Elbert, Jefferson, Larimer, and Weld Counties, Colorado (Figure 1). Although habitats are suitable and connected to occupied habitats across the Douglas County line, trapping has not captured the PMJM in Arapahoe or Teller Counties, Colorado. The North Platte River at Douglas, Wyoming, marks the northernmost confirmed location for the PMJM (Bowe and Beauvais 2012, pp. 8, 16). Specimens from Colorado Springs, Colorado, mark the southernmost documented location for the PMJM.

Elevation and Overlapping Range With the Western Jumping Mouse

The PMJM is generally found at elevations between 1,420 m (4,650 ft) and 2,300 m (7,600 ft). At the lower end of this elevation gradient, the semi-arid climates of southeastern Wyoming and eastern Colorado limit the extent of riparian corridors, thereby restricting the range of the PMJM (Beauvais 2001, p. 3). As a result, the dry, shortgrass prairies likely define the eastern

boundary for the PMJM, serving as a barrier to eastward expansion (Beauvais 2001, p. 3). In Wyoming, the PMJM has not been found east of Cheyenne, Laramie County, or west of the Laramie Mountains (Keinath 2001, p. 7; Keinath
et al.
2010, p. A6-185, Bowe and Beauvais 2012, pp. 8, 16). In Colorado, the PMJM has not been found on the extreme eastern plains (Clippinger 2002, pp. 20-21; USFWS 2013).

At the higher elevations, overlapping range with the western meadow jumping mouse complicates discerning areas occupied by the PMJM (Long 1965, pp. 665-666; Clark and Stromberg 1987, pp. 184-187; Schorr 1999, p. 3; Bohon
et al.
2005; Hansen 2006, pp. 24-27; Schorr
et al.
2007, p. 5). Unfortunately, differentiation between the PMJM and the western jumping mouse is difficult in the field (Conner and Shenk 2003a, p. 1456), complicating the results of surveys at high elevations. Generally, the western jumping mouse occurs in montane and subalpine zones, and the PMJM occupies lower elevations, in the plains and foothills (Smith
et al.
2004, p. 10; Bowe and Beauvais 2012, pp. 1, 8, 15-16). The PMJM may also have a stronger preference for riparian and wetland environments than the western jumping mouse, with limited forays into adjacent uplands (Bowe and Beauvais 2012, p. 1).

Because of this difficulty of field identification, many jumping mice have been trapped and released without being conclusively identified as either a PMJM or a western jumping mouse. Western jumping mice have been verified at elevations well below the upper elevation limit of the PMJM (Smith
et al.
2004, p. 11) leading to difficulty in making assumptions regarding identification based on elevation. Overlapping ranges for these subspecies have been verified within the Glendo Reservoir and the Lower Laramie and Horse Creek drainages in Wyoming (Conner and Shenk 2003b, pp. 26-27, 34-37; Meaney 2003; King 2006a; King 2006b; King
et al.
2006b, pp. 4351-4353), and within the Cache La Poudre, Big Thompson, and Upper South Platte River drainages in Colorado (Bohon
et al.
2005; Hansen 2006, pp. 24-27; King 2005; King 2006a; King
et al.
2006b, pp. 4351-4353; Schorr
et al.
2007).

Although difficult to distinguish in the field, body weight, body length, dentition, skull measurements, and genetic analysis can differentiate meadow jumping mice from western jumping mice (Krutzsch 1954, pp. 351-384; Klingenger 1963, p. 252; Riggs
et al.
1997, pp. 6-11; Conner and Shenk 2003a; Ramey
et al.
2005, p. 332; King
et al.
2006b, p. 4341). The approximation of the PMJM's range emphasizes locations where individual mice were positively identified through genetic analysis, or secondarily, with high probability through morphometric measurements rigorously analyzed by statistic methods, such as discriminate function analysis (DFA) (Conner and Shenk 2003a). Positive identification of individual mice through genetic analysis or other means is most important in habitats where the PMJM and the western jumping mouse coexist.

In Wyoming, the highest elevation, genetically confirmed PMJM capture is from approximately 2,300 m (7,600 ft), but the second highest is from only approximately 2,100 m (6,800 ft). The lowest confirmed western jumping mouse is from approximately 1,900 m (6,200 ft) (Bowe and Beauvais 2012, pp.15-16). Therefore, overlap with western jumping mice appears to occur in most of Wyoming's drainages that are occupied by the PMJM. In Colorado, with few exceptions, jumping mice positively identified below 2,050 m (6,700 ft) have been PMJMs. Between 2,050 m (6,700 ft) and 2,320 m (7,600 ft) in Colorado, PMJMs and western jumping mice are known to have overlapping distribution in the Cache La Poudre, Big Thompson, and Upper South Platte River drainages.

In coordination with WYNDD, the State of Wyoming, and CPW, we maintain a PMJM trapping database (Service 2013). We used this database to map the PMJM's approximate current range as illustrated in Figure 1. Given the wide areas of overlapping range between the PMJM and western jumping mice in Wyoming, we require that each Wyoming specimen be assessed via genetic analysis (consistent with Bowe and Beauvais 2012) in order to be considered a confirmed PMJM. In Colorado, we consider a jumping mouse to be a PMJM when identification has been confirmed via genetic analysis or DFA, or when, if unconfirmed, the mouse was captured below 2,050 m (6,700 ft), where western jumping mice have rarely been documented.

Trapping results approximate a species' range, but may not provide a definitive range because surveys have not occurred throughout all locations where the PMJM is likely to be present. For example, PMJMs were trapped at two sites approximately 19 km (12 mi) apart along Kiowa Creek in Elbert County (Service 2013). Suitable habitats between these capture locations suggest that the PMJM likely occurs both between these sites and farther downstream in the drainage. However, no trapping has occurred to confirm or deny this assertion. Similarly, on Trout Creek, trapping identified a PMJM in Douglas County near the Teller County line, and it is reasonable to assume the subspecies also may occur farther to the south in Teller County (Service 2013). Therefore, in the absence of trapping records, we rely on habitat suitability and connectivity to approximate the PMJM's current range.

Abundance and Populations

Due to the difficulty of implementing long-term trapping studies, quantitative studies designed to estimate PMJM populations have occurred at only a few sites in Colorado. As a result, we lack a reliable regional, Statewide, or rangewide population estimate for the PMJM. Without long-term trapping studies, our understanding of population densities is limited for the PMJM in Wyoming (WGFD 2005, p. 36; WGFD 2010, p. IV-2-66). In Colorado, we have several population estimates but little trend information for PMJM populations. In addition, because jumping mouse population sizes 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 one ongoing trapping study, population highs of 24 and 69 PMJMs per site were estimated for two control sites in 1999; subsequent trapping in 2002, during regional drought conditions, found no PMJMs present at either site (Bakeman 2006, p. 11). Over 4 years, PMJM populations varied widely and were absent at certain sites during some seasons, suggesting that 10 or more years of study might be necessary to assess the full extent of variation in PMJM populations (Meaney
et al.
2003, p. 620).

Because the PMJM occupies linear riparian communities, researchers estimate abundance as the number of mice per km (or mi) of riparian corridor. Estimates of linear abundance range widely, from 2 to 67 mice per km (3 to 107 mice per mi) with a mean of approximately 27 mice per km (44 mice per mi) (Shenk 2004).

The above abundance estimates, coupled with sufficient knowledge of occupied stream miles, may provide a rough indicator of PMJM numbers within a stream reach or drainage. The Recovery Team used the 27 mice per km (44 mice per mi) population estimate (Shenk 2004) to approximate the number of stream miles required to support varying sized populations of the PMJM (USFWS 2003b, p. 25). However, 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 PMJM's population size is the potential for including western jumping mice in the estimate (Bohon
et al.
2005; Hansen 2006, p. 174; Schorr
et al.
2007, p. 4). Overestimation is of particular importance in areas where the PMJM and western jumping mouse coexist, including many sites in Wyoming and higher elevation sites in Colorado. At these locations, actual densities of the PMJM are likely much lower than the trapping data suggest.

Although available PMJM population estimates do not incorporate estimates for riparian corridors along mountain, or montane, streams or any sites in Wyoming, capture rates provide insight into potential population sizes for these locations. At higher elevation riparian sites in Douglas, Jefferson, and Teller Counties, Colorado, capture success rates range from 0.32 percent to 0.6 percent, despite incredible trapping efforts (Hansen 2006, p. 94; Schorr
et al.
2007, p. 4). In, Wyoming, capture rates ranged from 0.5 percent to 1.3 percent (Griscom
et al.
2007). These low capture rates were likely lower, with results confounded by the coexistence of the western jumping mouse. Comparatively, capture rates ranged from 3.4 percent to 3.5 percent in high-quality habitat at lower elevations with similar trapping efforts (Schorr 2001, p. 18; Meaney
et al.
2003, p. 616). Therefore, montane and headwater stream reaches likely support a lower density of mice than plains and foothill sites, and are potentially less secure than their counterparts on the plains, especially where isolated.

Population Trends

As with abundance estimates, the difficulty of implementing long-term trapping studies limits the availability of population trend data for the PMJM. Since listing, there have been few attempts to characterize changes in PMJM populations over time. One long-term study at the Air Force Academy (Academy) in El Paso County, Colorado, provides the most thorough estimate of population trends for the subspecies. Mark-recapture data over 7 years at the Academy suggested that populations were declining (Schorr 2012a, p. 1277).

Without comprehensive population estimates for the PMJM, surveys at historically documented sites provide the primary basis for assessing population trends (Smith
et al.
2004, p. 29). As previously discussed, we now have much more information regarding PMJM's distribution in Wyoming and Colorado than we had at time of listing in 1998. For Wyoming, we initially cited only 2 known occupied sites, but trapping efforts since then have identified at least 30 occupied sites (Bowe and Beauvais 2012, p. 16). Much of what we noted at the time of listing to be historical range of the PMJM in Wyoming has now been found to currently support the subspecies, except for habitats west of the Laramie Mountains and in Goshen County. However, while many jumping mice captures have been confirmed as PMJM in the North Platte River basin through genetics or other techniques, trapping records suggest the subspecies is uncommon in the South Platte River basin, with only western jumping mice confirmed at several locations within the presumed historical range of the PMJM. Because trapping efforts targeting the PMJM prior to listing were few compared to those post-listing, we cannot infer population trends from the Wyoming trapping data. However, low capture rates for the PMJM suggest that the mouse may not be widely distributed (Cudworth and Grenier 2011, p. 154).

In Colorado, historical trapping records establish that the PMJM 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; Fitzgerald
et al.
1994, p. 293; Clippenger 2002, p. 18). However, recent trapping efforts have documented that the PMJM is currently rare or absent from these same areas (Ryon 1996, p. 2; Clippinger 2002, p. 22; USFWS 2013). This pattern is especially apparent along prairie riparian corridors directly or indirectly impacted by human development.

Summary of Information Pertaining to the Five Factors

Section 4 of the Act (16 U.S.C. 1533) and implementing regulations (50 CFR 424) set forth procedures for adding species to, removing species from, or reclassifying species on the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, a species may be determined to be endangered or threatened based on any of the following five factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

We must consider these same five factors in delisting a species. We may delist a species according to 50 CFR 424.11(d) if the best available scientific and commercial data indicate 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.

In making this finding, information pertaining to the PMJM in relation to the five factors provided in section 4(a)(1) of the Act is discussed below. In considering what factors might constitute threats, we must look beyond the mere exposure of the species (or in this case, subspecies) to the factor to determine whether the species responds to the factor in a way that causes actual impacts to the species. If there is exposure to a factor, but no response, or only a positive response, that factor is not a threat. If there is exposure and the species responds negatively, the factor may be a threat and we then attempt to determine how significant a threat it is. If the threat is significant, it may drive or contribute to the risk of extinction of the species such that the species warrants listing as endangered or threatened as those terms are defined by the Act. This does not necessarily require empirical proof of a threat. The combination of exposure and some corroborating evidence of how the species is likely impacted could suffice. The mere identification of factors that could impact a species negatively is not sufficient to compel a finding that listing is appropriate; we require evidence that these factors are operative threats that act on the species to the point that the species meets the definition of an endangered or threatened species under the Act.

Foreseeable future is determined by the Service on a case-by-case basis, taking into account a variety of species-specific factors such as lifespan, genetics, breeding behavior, demography, threat-projection timeframes, and environmental variability. For the purposes of this finding, 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 2040 in Colorado and 2030 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 the PMJM through 2040 in Colorado and 2050 in Wyoming. Climate change models formulate predictions through 2050 for the PMJM's range. Such projections frame our analysis as they help us understand what factors can reasonably be anticipated to meaningfully affect the subspecies' future conservation status. Therefore, we consider the foreseeable future for PMJM, based on the currently available data, to extend to approximately 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. We also believe that not all threat factors are necessarily foreseeable over the same time horizon. When reliable data are available, we consider a longer time horizon, while recognizing that there may not necessarily be just one foreseeable future.

In making our 12-month finding on these petitions, we considered and evaluated the best available scientific and commercial information.

Factor A. Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range

Introduction:
Decline in the extent and quality of PMJM habitat due to land-use changes associated with human development remains 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 the PMJM as threatened, we stated that land in 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 (63 FR 26517, May 13, 1998). We find that this trend continues, with human development contributing to the continued loss and degradation of PMJM habitat, as discussed further below.

In our original listing decision, we determined that PMJM 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. Threats included: 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 PMJM by directly destroying its protective cover, nests, food resources, and hibernation sites; disrupting normal feeding, breeding, or sheltering behaviors; or acting as a barrier to movement. We noted that such impacts reduced, altered, fragmented, and isolated habitat to the point where PMJM populations may no longer persist. We also noted that patterns of capture suggested that PMJM populations fluctuate greatly over time at occupied sites, raising questions regarding security of currently documented populations that are isolated and affected by human development.

For this status review, we received no new information or data that dispute these assertions. Rather, human populations and the corresponding threats associated with human development continue to expand and affect the PMJM and its habitats. Therefore, we find that the PMJM continues to face threats associated with loss and degradation of its habitats from human development, as is described below.

Absence of PMJM from historically occupied sites:
Pre-1980, historical records of the PMJM in Colorado illustrate areas of occupancy along the Front Range within both foothill and prairie riparian corridors (Armstrong 1972, p. 249; Fitzgerald
et al.
1994, p. 293; Fitzgerald
et al.
2011, p. 189). Between 1980 and 2011, the human population of Colorado counties within this historic part of the PMJM's range increased by approximately 84 percent, from approximately 1.9 million to 3.5 million (Colorado Demography Office 2011). As explained below, the apparent absence of the PMJM in areas affected by substantial development, where trapping had previously confirmed the subspecies' presence, supports the conclusion that human land uses adversely affect PMJM populations.

Trapping studies and investigations into land-use changes suggest that urban development directly altered or fragmented habitats such that the PMJM disappeared from these habitats (Ryon 1996, pp. 1, 25, 30). PMJMs were captured at only one of seven historically occupied sites with suitable habitats (Ryon 1996, p. 1). Additionally, distribution maps developed from museum records, published accounts, and unpublished reports suggest a loss of PMJM populations in expanding urban and suburban areas, especially around Cheyenne, Denver, Colorado Springs, and along the eastern extent of historical range (Clippinger 2002, pp. 14-29). The apparent loss of the PMJM from historically occupied sites suggests that human development negatively impacts PMJM's habitats.

As a result of habitat loss due to human development, PMJM populations have little likelihood of occurrence along large portions of major river and stream reaches within the subspecies' historical range in Colorado including:

• The Cache La Poudre River within the 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 east to I-25, 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 the 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 nearby capture is described above);

• Cherry Creek from the Arapahoe County-Douglas County line downstream through Denver to the South Platte River, 30 km (19 mi); and

• Monument Creek downstream from its confluence with Cottonwood Creek through Colorado Springs, approximately 15 km (9 mi).

In summary, PMJM populations appear to have little likelihood of occurrence along historically occupied river and stream reaches within and downstream from areas of concentrated human development. Despite these downstream extirpations, many of these same rivers and streams continue to support PMJM populations in their upstream foothills or montane reaches and tributaries, where human development is limited or has not occurred.

The PMJM Science Team developed a conservation planning handbook that addressed threats within each of seven Colorado counties supporting PMJM populations (Pague 1998; Pague and

Grunau 2000). The document identified potential threats operating in known or suspected PMJM habitat, and assigned a qualitative risk assessment level to each of the identified threats. The document provides important, science-based insight into threats to, and potential conservation strategies for, the PMJM in Colorado on a county-by-county basis (Pague and Grunau 2000). Habitat-related “issues” identified by the Science Team as high or very high priority include: Habitat conversion through housing, commercial, and industrial construction; travel corridor, or 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).

CPW's Comprehensive Wildlife Conservation Strategy cites threats to PMJM 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 (CPW 2006, p. 102). The Wyoming State Wildlife Action Plan (SWAP) describes suitable PMJM habitat as widely distributed, but naturally fragmented and very limited (WGFD 2010, p. IV-2-66). Wyoming's SWAP noted that while distribution is restricted with limited ability to increase distribution, extirpation is not imminent in Wyoming. However, the SWAP considers human activity to be a moderate limiting factor for the PMJM in Wyoming (WGFD 2010, p. IV-2-66). Wyoming's Comprehensive Wildlife Conservation Strategy identified potential threats to habitat areas most likely to support the PMJM as invasive plants, residential development radiating from Cheyenne, and recreation (WGFD 2005, pp. 53, 55, 56)

The loss of the PMJM from historically occupied sites suggests that human land uses adversely affect the PMJM. It is unlikely that the PMJM can return to historically occupied habitats that are now heavily developed. Furthermore, the PMJM's apparent local extirpation from areas of human development foreshadows the potential impacts of future development within the remaining range of the PMJM. Threats associated with human development, as discussed in more detail below, will continue to adversely affect the PMJM in large portions of its current range now and into the foreseeable future. If the protections of the ESA were to be removed, threats from human development would go unchecked.

Since listing in 1998, the Act's protections have slowed impacts of development on the PMJM and its habitat. One indication of human development pressure 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 preventing Federal actions from jeopardizing the continued existence of the subspecies or resulting 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. Below, we summarize our regulatory activities for the PMJM under the Act to illustrate the scope of impacts that would potentially occur in the absence of the Act's protections.

As of April 8, 2013, we have conducted 170 formal section 7 consultations (153 in Colorado, 17 in Wyoming) since the time of listing. Additionally, we issued 21 HCP-related incidental take permits (all in Colorado) for projects affecting the PMJM. We authorized take of the PMJM for actions that did not jeopardize the subspecies, but may have resulted in permanent impacts to over 320 ha (790 ac) of PMJM habitat, and temporary impacts to 609 ha (1,505 ac) of habitat, or approximately 0.8 percent and 1.7 percent of the subspecies' occupied range based on data layers provided by Colorado Parks and Wildlife (USFWS 2013). These projects incorporated conservation measures or mitigation to avoid or minimize the adverse impacts to the PMJM. Since 2006, we collaborated on more than 1,900 Federal or non-Federal projects, to avoid and minimize impacts to the PMJM and its habitat such that formal consultation under section 7 or an HCP was unnecessary.

However, even with the protections afforded to the subspecies under the Act, we have concluded that habitat overall has continued to decline in quality and quantity since listing, especially in Colorado. In the absence of listing, development projects in PMJM habitat would go forward with reduced Federal oversight. Under Factor D, we evaluate other Federal, as well as State and local regulatory mechanisms that may provide protection for the PMJM and its habitat.

Below we evaluate specific modes of human development and how they affect the PMJM, including: (1) Residential and commercial development; (2) transportation, recreation, and other rights-of-way through PMJM habitats; (3) hydrologic changes associated with human development; (4) aggregate mining; (5) oil and gas exploration and extraction; (6) agriculture; and (7) cattle grazing.

Residential and Commercial Development:
Clippinger (2002) assessed the impacts of residential development on the PMJM. He analyzed Colorado land-cover data compared to positive and negative trapping results for the PMJM in a GIS analysis and concluded that the likelihood of successful trapping of PMJMs within its historical range 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). The PMJM can be a useful indicator of environmental integrity in riparian areas and associated upland areas in the Colorado Piedmont (Clippinger 2002, p. iv). These data suggest that nearby development increases the risk of local extirpation of the PMJM from occupied sites.

Both housing density and spatial patterns can influence effects of residential development on wildlife habitat (Theobald
et al.
1997). While clustered development can decrease habitat disturbance (Theobold
et al.
1997, p. 34), much of the Rocky Mountain West is experiencing “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.
1996, p. 420). The Larimer County Master Plan (Larimer County Planning Division 1997) cites a trend toward residential properties with relatively large lots that 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.
1996, p. 402), the favored habitat of the PMJM. 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.
1996, p. 402). Rural development also 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 has subtle effects on riparian habitat. Human settlement results 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; Pennington
et al.
2008, pp. 1235, 1240-1244). An open understory does not favor the PMJM, which prefers dense ground cover of grasses and shrubs and is less likely to use open areas where predation risks are higher (Clippinger 2002, pp. 69, 72; Trainor
et al.
2007, pp. 472-476). Human development tends to increase densities of invasive plants that can outcompete native riparian and upland vegetation. Human development also increases populations of human-associated predators, such as domestic cats, red fox, or racoons that may impact PMJM populations.

Furthermore, human development fragments PMJM habitats, which isolates populations and reduces connectivity. The PMJM is closely associated with narrow riparian systems that represent a small percentage of the overall landscape within the subspecies' range. As a result, PMJM habitats may be naturally fragmented by a lack of connectivity, as montane and foothill drainages form rivers that flow onto the plains and may only join east of the potential range of the PMJM. However, human development, most intense on the plains and nearby foothills, further limits downstream connectivity and fragments habitats. Fragmentation of these linear riparian habitats limits the extent and size of PMJM populations. As populations become fragmented, isolated, and smaller, it becomes more difficult for them to persist (Caughley and Gunn 1996, pp. 165-189). The Recovery Team determined that small, fragmented units of habitat will not be as successful in supporting the PMJM in the long term as would larger areas of contiguous habitat (USFWS 2003b, p. 21). On a landscape scale, maintenance of dispersal corridors linking patches of PMJM habitat, and therefore connecting populations, may be crucial to the subspecies' conservation (Shenk 1998, p. 21; Schorr 2012a, pp. 1273, 1279). Limited travel distances recorded for the PMJM underscore the importance of continuous, interconnected suitable habitats.

Rapid development accompanied the growth of human populations along Colorado's Front Range (Kuby 2007; Schorr 2012, p. 1279). Population forecasts predict that Colorado's human population will increase by 1.5 percent per year between 2012 and 2017, with the growth rate increasing to 1.7 percent per year by 2020 (DeGroen 2012, p. 3). The State of Colorado expects the population of counties supporting the PMJM to increase by an additional 1.2 million people, a 50 percent increase, from 2011 to 2040 (Colorado Demography Office 2012). These expected population increases into the foreseeable future accompanied by more development, support Pague and Grunau's (2000) conclusion that habitat conversion to human development is a very high concern to the PMJM.

Although Wyoming has a smaller human population than Colorado, Wyoming's human population continues to increase within the range of the PMJM. Between 1980 and 2011, Wyoming's human population within the counties supporting the PMJM increased by 23 percent, from 123,755 to 152,120 people. In Cheyenne, Wyoming, human populations increased by 27 percent, from 47,283 to 60,096 (Wyoming Department of Administration and Information 2012). Over the 10-year period between 2000 and 2010, human populations increased by an average of 9.8 percent in Albany, Converse, Platte, and Laramie Counties, with a population decrease recorded for Platte County (Wyoming Department of Administration and Information 2012). Population forecasts predict that all four Wyoming counties within the PMJM's range will experience population increases by 2030. The models predict that populations in the counties supporting the PMJM will increase by 20,410 people, or 13 percent, between 2012 and 2030 (Wyoming Department of Administration and Information 2012). Laramie County will experience the largest increase, approximately 13,470 people between 2012 and 2030, or a 14 percent increase, with Cheyenne gaining approximately 8,372 people (Wyoming Department of Administration and Information 2012).

Population growth rates and projections provide valuable insight into future development pressures throughout the PMJM's range, but may overestimate impacts to areas that are already developed. For example, human population increases within already dense metropolitan centers, such as Cheyenne, Fort Collins, Greeley, Longmont, Denver, and much of Colorado Springs, are likely to have little direct impact on the PMJM because the mouse is likely absent within these heavily developed areas and any habitats downstream. However, development-related impacts would likely concentrate at the edges of these metropolitan areas, especially as they expand outward into undeveloped habitats to accommodate increasing populations. For example, substantial human population increases in the Laramie Foothills of Larimer County, Colorado, or southern portions of Douglas County, Colorado, are likely to impact the PMJM. In Wyoming, given the smaller projected population increases, rural development may continue to have fewer or more-localized impacts to the PMJM than in Colorado. However, rural development in the Wyoming and Colorado foothills targets valley bottoms with riparian habitats (Riebsame
et al.
1996, p. 402; Theobold
et al.
2001, pp. 4-5), resulting in an increased loss and fragmentation of PMJM habitats.

Modeling exercises also provide 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 or conservation easements, such models can add to our understanding of likely development patterns. For example, in 2005, the 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 illustrate significant increases in urban/suburban, low-density suburban, and exurban land uses across virtually all private lands within the Colorado portion of the PMJM's range. These models also predict urban and exurban expansion around Cheyenne through 2050 (Center of the American West 2001). These projections depict that only small, isolated patches of PMJM habitat in public ownership, including headwater areas in Federal ownership, would avoid the direct impacts of residential and associated commercial

development. While land-use modeling and projections retain uncertainties and are not at a resolution useful for assessing habitat patterns, both the empirical record and the projections show development filling gaps along the Colorado Front Range (Travis 2008).

Our regulatory activities under the Act provide insight into the scope of development-related impacts that have occurred since listing. Of the 153 formal consultations and 21 HCPs completed in Colorado, 19 section 7 consultations and 10 HCPs were specifically for residential and commercial developments with direct adverse effects to the PMJM or its habitat. Approved projects allowed for permanent or temporary adverse impacts in excess of 210 ha (520 ac) of PMJM 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 hampered by factors such as drought or flooding. We also have worked with other Federal agencies and a substantial number of landowners and developers on more than 1,900 projects to avoid adverse impacts to PMJM habitat, thus avoiding formal consultation or the need for HCPs.

Additional planned residential and commercial development projects that would adversely affect PMJM habitat in Colorado are continually being reviewed by the Service. Since 2006, our biologists provided technical assistance to more than 470 development projects in Colorado with potential impacts to the PMJM (TAILS 2013). These data indicate that listing did not eliminate development pressures due to residential or commercial developments. Since listing, protections afforded under the Act have slowed, but not eliminated, the loss of PMJM habitat due to residential and commercial development in Colorado. Therefore, we conclude that in the absence of the protections under the Act, PMJM habitat in Colorado and the populations it supports would be lost at a greatly increased rate from residential and commercial development.

Based upon known impacts to the PMJM associated with current development and best available projections for future development, we conclude that residential and commercial development constitutes a substantial threat to the PMJM, now and into the future.

Transportation, Recreation, and Other Rights-of-Way through Habitat:
At the time of listing, we concluded that roads, trails, or other linear development through the PMJM'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 PMJM habitat. Since listing, we have conducted 69 formal consultations under section 7 of the Act for road or bridge projects (62 in Colorado and 7 in Wyoming), resulting in permitted impacts to approximately 84 ha (207 ac) of PMJM 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 PMJM habitat. Under the Douglas County (Colorado) Regional HCP for the PMJM, 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 PMJM habitat over a 10-year period.

One of the largest proposed road projects in PMJM habitat is the improvement to I-25 in El Paso County, Colorado. The proposed construction will affect all of the eastern tributaries of Monument Creek thought to support the PMJM (Bakeman and Meaney 2001, p. 21). Impacts to the PMJM will 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 will have significant cumulative effects on the PMJM in the Monument Creek drainage, especially east of I-25 (Bakeman and Meaney 2001, pp. i, ii, 22-27). Anticipated impacts include the permanent loss of 26 acres and temporary impacts to 36 acres of PMJM habitat (USFWS 2003, p. 23). A second large transportation project is the improvement of U.S. Highway 36 in Boulder County, Colorado. This project will permanently impact 42 acres of PMJM habitat along Boulder Creek (USFWS 2009, p. 23).

As the human population increases, more road construction and maintenance projects will be necessary to accommodate new development and transportation needs. Based on ongoing and anticipated transportation projects within the range of the PMJM, we determine that transportation-related threats continue to affect the PMJM. In the absence of the Act's protective measures, impacts to the PMJM and its habitats from these activities would likely increase.

Anthropogenic impacts associated with recreation include the development and use of backcountry roads, trails, and campgrounds, which are often located along streams and near water (WGFD 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 PMJM 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). Fewer PMJMs are found within sites near trails than on sites without trails (Meaney
et al.
2002, pp. 131-132). While temporal and spatial variation in PMJM 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 PMJM in 1998, 18 recreational trail projects with proposed impacts to PMJM habitat in Colorado received authorization for take or permits through section 7 consultations or HCPs, with impacts to approximately 36 ha (90 ac) of PMJM habitat. The Douglas County Regional HCP permitted an additional 24 trail projects in Colorado. Demand for recreational development in public open space and on conservation properties will likely increase as human populations increase (Bowker
et al.
2012, pp. 1, 5, 25-26). While human population growth is expected to be significant only along the Front Range of Colorado and perhaps in the Cheyenne, Wyoming area, increased recreational demand will radiate outward from dense, urban centers and extend into more, undeveloped rural lands. For example, the Pike National Forest immediately to the west of Denver, Colorado, experienced a 50 percent increase in recreational visitors between 2001 and 2006 (USFS 2013, p.1). Without protections afforded by the Act, PMJM populations on properties free from residential and commercial development threats will still be subject to threats from future recreational development and increased human use.

Many utility lines (sewer, water, gas, communication, and electric lines, and municipal water ditches) cross PMJM 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 PMJM, 68 utility projects adversely affecting the PMJM and its habitat have

been evaluated through section 7 consultations (64 in Colorado, 4 in Wyoming). In addition, an approved HCP with Denver Water permits impacts to 34 ha (84 ac) of PMJM 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 PMJM. If the PMJM were to be delisted, it is unlikely that project proponents would voluntarily avoid adverse impacts to the PMJM by directionally boring underneath habitat of Prebles to avoid impacts.

To summarize, as human populations increase, threats associated with transportation, recreation, and other rights-of-way through PMJM habitats will also increase. Because human populations are increasing and are projected to grow in the future, we expect these threats will continue to impact PMJM populations in Colorado and Wyoming in the foreseeable future. Wyoming's population will increase more slowly than Colorado's population, suggesting that there will be relatively lower impacts resulting from transportation, recreation and rights of way to PMJM populations in Wyoming.

Hydrologic Changes:
Establishment and maintenance of riparian plant communities depend on the interactions between surface-water dynamics, groundwater, and river-channel processes (Gregory
et al.
1991, pp. 542-545). Changes in hydrology can 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 PMJM in these riparian habitats due to the 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 the 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 2002a, pp. 182-186). Impervious surfaces significantly reduce infiltration of precipitation by natural soil substrates. 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 2002a, 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 PMJM. The methods used include channelization; construction of detention basins, outfall structures, drop structures, riprap banks, and 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 PMJM is so altered that populations can no longer persist. Bank stabilization is a high-priority issue for the PMJM in Weld and El Paso Counties (Pague and Grunau 2000, p. 15). Since the listing of the PMJM, 22 stormwater management, stream stabilization, or outfall structure projects with impact to PMJM habitat have been addressed through formal section 7 consultations in Colorado; none have occurred in Wyoming.

The PMJM'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 attributed to such changes in hydrology described above. Multiple researchers expressed concern regarding upstream development activities and the integrity of protected riparian habitats on Monument Creek and its tributaries through the Air Force Academy (Corn
et al.
1995, p. 14; Schorr 2001, p. 30; Schorr 2012a, p. 1279). In 2007, all eastern tributaries of Monument Creek on the Academy experienced adverse impacts to occupied PMJM habitat due to erosive head cutting, channel degradation, and impacts to vegetation attributed to regional stormwater management, and commercial and residential developments that occurred upstream and downstream (Mihlbachler 2007; Schorr 2012a, p. 1279). Despite the Air Force Academy's conservation efforts, damage to habitats on the Academy due to adjacent urbanization may be irreparable (Carley 2012).

If we were to delist the PMJM, runoff-related impacts to riparian habitats within and downstream of development would likely increase. Additionally, in the absence of the Act's protection the restoration of impacted riparian systems would be less likely to occur.

Hydrologic factors, such as surface flows and groundwater, influence the riparian habitats on which the PMJM depends. Water development and management alters vegetation composition and structure, riparian hydrology, and flood-plain geomorphology directly, as well as through alterations to habitats located downstream. The creation of irrigation reservoirs at the expense of native wetlands is a factor that negatively affected PMJM populations over the previous century (Fitzgerald
et al.
1994, p. 293). Reservoirs with barren shorelines can fragment populations and create barriers to the PMJM's movements. As reservoirs are maintained and developed, these factors continue to impact the PMJM and its habitats.

Population growth drives water consumption, so as Colorado's population doubles by the year 2050, so will the demand for water (CWCB 2010, pp. ES-4, ES-7). Current and future reservoir construction will be necessary to respond to municipal water needs. By 2050, municipal and industrial demand for water in Colorado's South Platte River basin would increase by 93 percent and by 78 percent in the Arkansas River basin, as measured in acre feet (af) per year under medium-use scenarios (Colorado Water Conservation Board 2010, p. 3-11, Table 3-3). Additionally, demand within the

Denver metropolitan area would increase by 59 percent under medium-use scenarios (Colorado Water Conservation Board 2010, p. 3-11, Table 3-3). The expanded storage and transport of water that will be needed to address these demands has the potential to significantly impact PMJM habitat. Pague and Grunau (2000) considered hydrological impacts (water quality, flow regime, and groundwater) to be a high-priority issue to the PMJM in all Colorado counties supporting populations.

Since the listing of the PMJM, we have conducted two section 7 consultations for new reservoirs in Colorado, the Reuter-Hess Reservoir in Douglas County and the Pinewood Springs Reservoir in Larimer County. Through these consultations, 7 ha (17 ac) of impacts to PMJM habitat were authorized. Three water projects currently proposed would, if developed, significantly affect PMJM habitat, including the proposed expansions of existing Halligan Reservoir and Seaman Reservoir in the Cache La Poudre drainage, Larimer County, Colorado, and Chatfield Reservoir Storage Reallocation Project 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 PMJM habitat and affect the PMJM'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 the PMJM's critical habitat. The preferred alternative for the Chatfield Reservoir Storage Reallocation Project estimates that up to 183 ha (453 ac) of existing PMJM habitat, including 63 ha (155 ac) of critical habitat, would be inundated. These and other water projects also will result in alteration of flows that could further affect PMJM habitat downstream.

In Wyoming, estimates of projected water use in the Platte River Basin through 2035 range from a 38 million m
3
(31,000 af) decrease to a 90 million m
3
(73,000 af) increase (Wyoming Water Development Commission 2006, p. 10). No significant reservoir projects are currently planned within PMJM 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 the PMJM are uncertain because it is not known whether the PMJM occurs in the drainage.

Beyond direct effects to the PMJM and its habitat through construction or inundation, changes in flows related to water diversion, storage, and use also affect downstream riparian habitats in a variety of ways. In the future, a number of changes in amount and timing of diversions, water uses, and return flows will affect many streams supporting the PMJM. However, the cumulative impacts of such changes to specific PMJM populations, both adverse and some potentially beneficial, are difficult to predict. As flows are captured or diverted, or as groundwater supplies are depleted through wells, natural flow patterns are changed, and more xeric plant communities may replace the riparian vegetation. On-stream reservoirs disrupt natural sediment transport and deposition. Loss of sediment encourages channel downcutting, which in turn affects groundwater levels (Katz
et al.
2005, p. 1020). The resulting conversion of habitats from moist or mesic, shrub-dominated systems to drier grass- or forb-dominated systems make the area less suitable for the PMJM.

Considering the projected future demands for water, we conclude that major water development projects affecting the PMJM would likely occur regardless of the status of the subspecies under the Act. However, if we delisted the PMJM, conservation measures designed to minimize and compensate impacts to PMJM and its habitats are less likely to be incorporated into project plans. Although development pressures for water resources are likely less in Wyoming, a similar scenario of increased population growth, followed by increased development and demand for water, suggests that if delisted, fewer projects would incorporate PMJM-specific conservation measures. Therefore, we determine that hydrologic changes are a threat to the PMJM.

Aggregate Mining:
At the time of listing, we concluded that alluvial aggregate mining was a threat to the PMJM. Aggregate mining removes mineral materials from floodplains, where mineral resources most commonly occur. These mining operations often occur on the same gravel deposits that provide important PMJM hibernation sites (63 FR 26517, May 13, 1998). As a result, alluvial aggregate mining continues to be a threat to the PMJM and may produce long-term changes to PMJM habitat by altering hydrology and permanently removing shrub and herbaceous vegetation. Additionally, after mining removes the aggregate minerals, operators often line the remaining pits with impervious substrates, effectively converting the mine pit into a water reservoir. This conversion precludes the 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 PMJM at two aggregate mines in Colorado. We have worked with project proponents to avoid impacts at others. Previously, private aggregate mining activities at Rocky Flats National Wildlife Refuge (NWR) in Colorado could potentially affect PMJM habitat directly or through alteration of hydrology along Rock Creek. However, a recent land exchange and donation of mineral estates prevents future mining on an additional 245 ha (605 ac) within the Refuge boundary (USFWS 2012, pp. 19-20). Therefore, aggregate mining is not likely to impact the PMJM or its habitat at Rocky Flats NWR.

Elsewhere, aggregate mining continues to affect floodplains along Colorado's Front Range, but many project sites are along downstream reaches of larger streams and rivers where PMJM populations now appear absent. Pague and Grunau (2000) considered “rock and sand extraction” to be a high-priority issue in Weld, Jefferson, and Douglas Counties. While some stream channels within the range of the PMJM in Wyoming have historically been mined for aggregate, including the Laramie River at Laramie and Lodgepole and Crow creeks at Cheyenne, mining is not as widespread as in Colorado (Wyoming State Geological Survey (WSGS) 2008, 2012).

Construction aggregates are low in value relative to their weight, so transporting the minerals is expensive and mines are usually located as close to the point of use as possible (WSGS 2008). As a result, threats related to aggregate mining are likely to be more intense near areas with human development. Thus, we deduce that aggregate mining will continue throughout the subspecies' range, but may have a greater impact on PMJM populations in Colorado where development pressures are greater than in Wyoming. However, these pressures could increase in Wyoming alongside projected increases in human population and urban development, particularly around Cheyenne. Therefore, we conclude that aggregate mining is a threat to the PMJM.

Oil, Gas, and Mineral Exploration and Extraction:
We investigated whether oil, gas, and mineral exploration and extraction pose a threat to the PMJM. A large portion of the subspecies' Wyoming range overlaps with exposed, undifferentiated precambian rocks or other formations with low potential for oil and gas development (DeBruin

2002). A GIS analysis of oil and gas potential (Anderson 1990) relative to the subspecies' likely range (Beauvais 2004) indicates that approximately 79 percent of the PMJM's range in Wyoming occurs in areas with low oil and gas potential. This analysis also indicates that less than 1 percent of the PMJM's range in Wyoming occurs in areas with high oil and gas potential, while approximately 20 percent of the range overlaps with areas of moderate oil and gas potential. Even within these moderate and high potential areas, only one oil and gas field occurs in PMJM habitat (DeBruin 2002). In addition, coalfields and the range of the PMJM have little overlap in Wyoming (DeBruin 2004, p. 2), indicating a minimal risk of PMJM habitat being altered for coal production. Additionally, the PMJM's range does not overlap with coal production areas in Colorado.

In Colorado, many new wells are drilled on the plains within or to the east of the Front Range urban corridor, with many new wells in Weld County. Few PMJMs exist in areas of current oil and gas exploration and production, and few PMJM habitats overlap with these areas. In addition, wells are usually located in upland areas away from riparian habitats that support PMJM populations, though associated roads and pipelines may cross or parallel creeks and riparian habitats. Based on the limited potential for development of these resources within the range of the PMJM, we conclude that oil and gas activities (directly or indirectly) will not meaningfully affect the conservation status of the PMJM throughout its range now or in the future. Therefore, we conclude that oil and gas exploration and extraction are not currently threats to the PMJM.

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 the PMJM. They concluded that development of irrigat

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2013-12387. Public record. Not legal advice.