[Federal Register Volume 78, Number 101 (Friday, May 24, 2013)]
[Proposed Rules]
[Pages 31680-31712]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-12387]



[[Page 31679]]

Vol. 78

Friday,

No. 101

May 24, 2013

Part III





Department of the Interior





-----------------------------------------------------------------------





Fish and Wildlife Service





-----------------------------------------------------------------------





50 CFR Part 17





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

  Federal Register / Vol. 78 , No. 101 / Friday, May 24, 2013 / 
Proposed Rules  

[[Page 31680]]


-----------------------------------------------------------------------

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

[[Page 31681]]

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

[[Page 31682]]

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

[[Page 31683]]

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

[[Page 31684]]

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;

[[Page 31685]]

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

[[Page 31686]]

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,

[[Page 31687]]

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.

[[Page 31688]]

[GRAPHIC] [TIFF OMITTED] TP24MY13.007

    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

[[Page 31689]]

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

[[Page 31690]]

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

[[Page 31691]]

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

[[Page 31692]]

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

[[Page 31693]]

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

[[Page 31694]]

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

[[Page 31695]]

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

[[Page 31696]]

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

[[Page 31697]]

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 irrigated 
farmland had a negative impact on PMJM habitat, and that any habitat 
creation it produced was minimal (Compton and Hugie 1993a; Compton and 
Hugie 1993b). In general, negative trapping results suggest that the 
PMJM does not occur in areas cultivated for row crops. Historically, 
the rapid rate of native habitat conversion to row crops likely had a 
significant adverse impact on the PMJM. Because conversion of native 
habitat to row crops has become increasingly rare in both Colorado and 
Wyoming (USDA 2009, Tables 2, 3, & 9), such conversions are unlikely to 
present a similar threat in the future in any portion of the 
subspecies' range.
    Although future pressures to increase agricultural production may 
result from changes in the industry, including potential demand for 
biofuels, we are not aware of information that suggests this would 
result in meaningful decreases in the PMJM's riparian habitat in 
Colorado or Wyoming. We conclude that in the absence of protections 
afforded by the Act, only a little of the subspecies' habitat is at 
risk from agricultural conversion. In Wyoming, where such a scenario in 
PMJM habitat appears more likely than in Colorado, we explored whether 
former cropland removed from production for conservation purposes is 
now being returned to production. For example, through the Farm Bill's 
Conservation Reserve Program (CRP), farmers and ranchers enroll 
eligible agricultural land in 10- to 15-year contracts and plant 
appropriate cover, such as grasses and trees, in crop fields and along 
streams. The plantings help prevent soil and nutrients from running 
into regional waterways and affecting water quality. The long-term 
vegetative cover also improves wildlife habitat and soil quality. 
Wildlife habitat provided through the CRP can be at risk when CRP 
contracts expire and lands are returned to agricultural production.
    Within the current range of the PMJM in Wyoming, Laramie County has 
the largest percent of croplands enrolled in the CRP program, at 9 
percent (FSA 2013, p. 97). Total enrollment within the four counties 
(Converse, Laramie, Platte, and Albany) is approximately 17 percent 
(FSA 2013, p. 97). Between 2013 and 2027, CRP contracts that will 
eventually expire for Wyoming counties within the current range of the 
PMJM include: 1,146 ha (2,832 ac) currently enrolled in Converse 
County; 17,891 ha (44,210 ac) currently enrolled in Laramie County; 
17,436 ha (43,086 ac) currently enrolled in Platte County (FSA 2012); 
and 25 ha (63 ac) currently enrolled in Albany County. Between 2007 and 
2012, enrollments declined 969 ha (2,395 ac) in Converse County; 
declined 11,923 ha (29,463 ac) in Laramie County; declined 6,971 ha 
(17,225 ac) in Platte County; and did not change in Albany County (Farm 
Service Agency 2012). However, with only 17 percent of croplands 
currently enrolled in the CRP program in Wyoming, future changes in 
enrollments are unlikely to affect the PMJM or its habitats.
    The PMJM uses native grass and alfalfa hayfields that are in or 
adjacent to suitable riparian habitat. Because hay production requires 
large amounts of water, hayfields are often near waterways and, thus, 
PMJM's riparian habitat. Mowing of hay may directly kill or injure 
PMJMs; reduce food supply, especially if plants do not mature to 
produce seed; and remove cover. Late season mowing may be especially 
problematic, because PMJM are approaching hibernation and their 
nutritional needs are high (Clippinger 2002, p. 72). Additionally, hay 
production may preclude the growth of willows and other shrubs that 
provide important hibernation sites for the PMJM. Ditch systems often 
irrigate hayfields, and the PMJM may use overgrown water conveyance 
ditches and pond edges, or other agricultural ditches as dispersal 
routes (Meaney et al. 2003, pp. 612-613). As a result, ditch 
maintenance activities may kill individual PMJMs and periodically alter 
their habitat. However, existing special regulations at 50 CFR 17.40(1) 
exempt certain ditch maintenance operations from the take prohibitions 
of the Act in recognition that habitat that the ditches provide is 
dependent on the ditches retaining their function. Furthermore, PMJM 
populations have persisted in hayed areas for many years (Taylor 1999), 
so haying operations that allow dense riparian vegetation to remain in 
place are likely compatible with persistence of PMJM populations. 
Therefore, agriculture is not currently a threat to the PMJM.
    Livestock grazing. Multiple scientific studies document the affects 
to riparian habitats from livestock grazing (Kauffman and Krueger 1984, 
pp. 431-435; Armour et al. 1991, pp. 7-11; Fleischner 1994, pp. 629-
638; Belsky et al. 1999, pp. 419-431; Freilich et al. 2003, pp. 759-
765). Livestock have damaged 80 percent of stream and riparian 
ecosystems in the western United States (Belsky et al. 1999, p. 419). 
Adverse impacts of grazing include: Changes to stream channels 
(downcutting, trampling of banks, increased erosion), flows (increased 
flow and velocity, decreased late-season flow), the water table 
(lowering of the water table), and vegetation (loss to grazing, 
trampling, and through altered hydrology) (Kauffman and Krueger 1984, 
pp. 432-435).
    Researchers have documented impacts to meadow jumping mice from 
cattle grazing (Medin and Clary 1989; Giuliano and Homyack 2004; Frey 
and Malaney 2009). Livestock grazing contributes to the lack of 
structural habitat diversity on historical PMJM sites in Colorado (Ryon 
1996, p. 3). Grazing practices that assure maintenance of riparian 
shrub cover may be a key consideration in maintaining PMJM populations 
(Ensight

[[Page 31698]]

Technical Services 2004, p. 9). On a working ranch in Douglas County, 
Colorado, PMJMs were detected within cattle exclosures, but not on 
grazed areas. Previous trapping had documented PMJMs upstream and 
downstream of the working ranch, but not on the grazed ranch itself 
(Ensight Technical Services 2004, p. 9). On private lands in Douglas 
County, Colorado, Pague and Schuerman (1998, pp. 4-5) observed a swift 
rate of residential land development and significant fragmentation of 
habitat, but noted that in some cases accompanying secession of grazing 
had allowed recovery of degraded riparian habitats. Along the Poudre 
River in the Arapaho Roosevelt National Forest in Larimer County, 
Colorado, continued vegetation monitoring reveals that resting 
overgrazed areas improved PMJM's riparian and upland habitats (Hansen 
and Ellwood 2013).
    A 5-year study of factors affecting jumping mice (Zapus spp.) on 
the Medicine Bow National Forest in Wyoming demonstrated an inverse 
relationship between percent utilization of cattle forage (mostly 
grasses) and nearby jumping mouse numbers. Grazing levels that resulted 
in more than 40 percent forage utilization were more influential in 
reducing jumping mouse numbers than lower grazing intensities (Griscom 
et al. 2009, pp. 11-12). In Colorado, City of Boulder lands endured 
intensive grazing, farming, or haying regimes until they became part of 
the Boulder Open Space system. Grazing and haying, used as land 
management tools, continue on Boulder Open Space sites currently 
supporting the PMJM. However, in their study of small mammals on 
Boulder Open Space, Meaney et al. (2002, p. 133) found no adverse 
effects of managed grazing on abundance of individual small mammal 
species or on species diversity.
    Overgrazing threats are not limited to large livestock producing 
operations. On subdivided ranch properties, often termed 
``ranchettes,'' horses and other livestock can heavily affect the small 
tracts within which they are fenced (Pague and Grunau 2000, pp. 1-14). 
In Colorado, many large ranch properties are subdivided into smaller 
ranchettes, with multiple homes and grazing pastures. We have concluded 
that this represents a widespread threat to undeveloped areas of 
Colorado, where an increase in rural development is forecast in the 
future. Pague and Grunau (2000) considered ``high impact livestock 
grazing'' to be a high-priority issue for the PMJM in Larimer, Weld, 
Elbert, and El Paso Counties in Colorado, largely due to the projected 
increase in such ranchettes.
    In Wyoming, where large-scale commercial ranching is more prevalent 
in the PMJM's range than in Colorado, overgrazing occurs sporadically 
across the landscape, in particular where cattle congregate in riparian 
areas during the winter and spring. Grazing has occurred within PMJM 
habitat for many decades, and populations of PMJMs have been documented 
on sites with a long history of grazing. For example, jumping mice were 
trapped at 18 of 21 sites on True Ranches properties (mice from 14 of 
these sites have since been confirmed as PMJMs (King et al. 2006b, pp. 
4351-4353)), primarily within sub-irrigated hay meadows that have been 
subjected to livestock grazing and hay production for approximately 100 
years (Taylor 1999, p. 5).
    At the time of listing, we addressed overgrazing by livestock. We 
stated that it may cause significant impacts to PMJM habitat, but that 
timing and intensity of grazing were probably important in maintaining 
habitat and that maintenance of woody vegetative cover could be key (63 
FR 26517, May 13, 1998). Overgrazing was thought to have eliminated the 
PMJM from much of its former Wyoming range (Clark and Stromberg 1987, 
p. 185; Compton and Hugie 1993b, p. 4). However, trapping efforts since 
listing identified PMJM in Wyoming and greatly expanded our 
understanding of the subspecies' range, disproving early theories that 
overgrazing eliminated the PMJM in Wyoming.
    As suggested by Bakeman (1997, p. 79) and Pague and Grunau (2000, 
pp. 1-17), and as supported by the examples above, grazing is 
compatible with the PMJM when timing and intensity are appropriately 
managed. We now believe that agricultural operations that have 
maintained habitat supportive of PMJM populations are consistent with 
conservation and recovery of the subspecies. As a result, we adopted 
special regulations at 50 CFR 17.40(1) in 2001, which exempted existing 
agricultural activities, including grazing, plowing, seeding, 
cultivating, minor drainage, burning, mowing, and harvesting, from the 
prohibitions of the Act. The exemption does not apply to new 
agricultural activities or to those that expand the footprint or 
intensity of the activity. We established the exemption to provide a 
positive incentive for agricultural interests to participate in 
voluntary conservation activities and to support surveys and studies 
designed to determine status, distribution, and ecology of the PMJM, 
which in turn could lead to more effective recovery efforts.
    The number of cattle in counties currently known to support the 
PMJM in Wyoming totaled 288,000 head in 2012 (National Agriculture 
Statistics Service 2012). Cattle numbers appear stable in Albany, 
Converse, and Laramie Counties, but higher than the average for the 
last 20 years in Platte County. Cattle numbers in Colorado counties 
supporting the PMJM totaled 706,900 head in 2012. Approximately 80 
percent, or 565,000 cattle, were in Weld County, where limited occupied 
PMJM habitat is known to exist (National Agriculture Statistics Service 
2012). Excluding Weld, all of these Colorado counties have shown a 
marked downward trend in cattle numbers over the past 20 years, 
reflecting human development on former agricultural lands (National 
Agriculture Statistics Service 2012).
    Overall, we expect traditional grazing operations to continue in 
Wyoming. Such operations have generally proven compatible with 
maintenance of PMJM populations, suggesting timing and intensity have 
generally been managed appropriately. This management has taken place 
without oversight of the Act as allowed in the special regulations at 
50 CFR 17.40(1). Researchers observed a correlation between grazing and 
drought while studying the New Mexico meadow jumping mouse, with 
populations more tolerant of grazing during wet years (Frey and Malaney 
2009, p. 37). While the management of these ranches may not change in a 
manner adverse to the PMJM into the future, cumulative impacts with 
future climate change and grazing present concerns (see Factor E 
discussion below).

Conservation Efforts To Reduce Habitat Destruction, Modification, or 
Curtailment of Its Range

    In Colorado, restoration of degraded riparian habitats has occurred 
in part as mitigation for adverse impacts to the PMJM. Restoration of 
0.86 km (0.54 mi) of PMJM habitat on East Plum Creek, Douglas County, 
appears to have increased vegetation cover and the PMJM's use (Bakeman 
2006, pp. 4, 8). The effort has restored connectivity of upstream and 
downstream riparian habitat through this previously degraded urban 
stream reach. Similarly, recent projects on Cherry Creek, Douglas 
County, have restored groundwater levels and downcut channels in or 
near PMJM habitat by employing rock or sheet pile drop structures.
    State programs have been available to help preserve the PMJM 
through the

[[Page 31699]]

acquisition, preservation, and management of its habitat. These include 
the Great Outdoors Colorado Trust Fund and the Species Conservation 
Trust Fund. There are many State and local initiatives that could 
provide for conservation of the PMJM, independent of Federal oversight, 
including nearly 40 conservation projects in 5 Front Range Colorado 
counties where the PMJM ``may be present'' (George 2004). However, the 
conservation value of many of these and other more recent projects is 
uncertain, since most were developed without specific regard to the 
PMJM's distribution and its conservation.
    Service-approved HCPs and their incidental take permits contain 
management measures and protections for identified areas that protect, 
restore, and enhance the value of these lands as habitat for the PMJM. 
These measures, which include explicit standards to avoid, minimize, 
and mitigate any impacts to the covered (sub)species and its habitat, 
are designed to ensure that the biological value of covered habitat for 
the PMJM is maintained, expanded, or improved. Large regional HCPs 
expand upon the basic requirements set forth in section 10(a)(1)(B) of 
the Act and reflect a voluntary, cooperative approach to large-scale 
habitat and (sub)species conservation planning. The primary goal of 
such HCPs is to provide for the protection and management of habitat 
essential for the conservation of the (sub)species while directing 
development to other areas. In any HCP, permittees may terminate their 
participation in the agreement and abandon the take authorization set 
forth in the permit.
    To date, we have approved 19 single-species HCPs for the PMJM, all 
in Colorado. These 19 HCPs and their 21 associated permits allow 
approximately 282 ha (696 ac) of permanent or temporary impacts to PMJM 
habitat. The HCPs describe the preservation and enhancement of habitats 
to offset impacts from proposed activities. The approved HCP for 
Douglas County and the Towns of Castle Rock and Parker allows impacts 
of up to 170 ha (430 ac), in exchange for the acquisition of 24 km (15 
mi) of stream (455 ha (1,132 ac) of habitat) acquired and preserved for 
the long-term benefit of the PMJM.
    Another HCP, issued in January 2006, is the Livermore Area HCP in 
Larimer County. The planning area for this HCP includes a large portion 
of Larimer County, approximately 1,940 square km (750 square mi), 
including a PMJM ``conservation zone'' estimated at approximately 324 
km (201 mi) of stream and 8,570 ha (21,320 ac). The HCP cites 
protection of 114 km (71 mi) of stream, mostly on CPW lands; however, 
it is not clear what proportion of these areas support the PMJM. Local 
landowners and public agencies holding land within the boundaries of 
this HCP may opt for coverage under the HCP and receive take permits on 
their own from us for activities consistent with the HCP. The Livermore 
Area HCP is designed to support current land uses, including ranching 
and farming. However, inclusion of landowners is optional, and they may 
choose to pursue land uses inconsistent with those specified in the 
HCP. Thus far, we have issued no individual permits under this HCP.
    Of the two other regional HCPs that have been in development, the 
El Paso County effort is proceeding slowly, if at all, and the Boulder 
County effort has been discontinued. It is unlikely that these or other 
conservation plans would be completed or implemented if the PMJM did 
not remain listed under the Act.
    Summary of Factor A: Human land uses within the PMJM's current 
range continue to destroy, degrade, and fragment habitats. Since the 
time of listing, the Act's protections have avoided, minimized, and 
helped to compensate for many direct human land-use impacts to PMJM 
habitats. Direct and secondary impacts to riparian habitats have likely 
diminished the areas capable of sustaining PMJM populations. Given the 
projections for future human population growth in Colorado and Wyoming, 
and absent protections associated with Federal activities and listing 
under the Act, we have concluded that threats posed by human 
development activities as discussed above will increase in the 
foreseeable future. Regulatory mechanisms other than the Act could help 
reduce such negative impacts, but are currently limited, as is 
discussed under Factor D below.
    Wyoming's human population is expected to increase by 2030. Human 
populations will grow more slowly in Wyoming than in Colorado, 
suggesting that fewer development-related threats are likely to occur 
in this portion of the subspecies' range than in Colorado. In the North 
Platte River basin in Wyoming, the PMJM appears to be more widely 
distributed than assumed at the time of listing, but the confirmed 
range is limited to a relatively narrow band east of the crest of the 
Laramie Mountains (Bowe and Beauvais 2012, p. 8). An improved 
understanding of the subspecies' distribution suggests that to date the 
PMJM has largely coexisted with historical and well-managed 
agricultural activities, such as grazing and haying. A continuation of 
these long-standing activities may support existing PMJM populations. 
However, we have little information to suggest if or how these 
agricultural practices are likely to change in the future.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    We have no information to suggest that the PMJM is currently 
collected for commercial or recreational purposes. We also have no 
information to indicate that collection or overutilization of the 
subspecies for commercial or recreational purposes would occur if the 
species were delisted.
    Conversely, collection of PMJM specimens for scientific and 
educational purposes does occur, primarily for research or during 
presence or absence trapping surveys related to development projects. 
The Act largely motivates these surveys and ensures that the collection 
does not jeopardize the subspecies. If delisted, we assume that 
scientific collection would decrease. Additionally, we assume that 
State wildlife agencies would continue to recognize PMJM as a non-game 
species if delisted; thus scientific and commercial activities would 
continue to be permitted under existing State regulations in both 
Colorado and Wyoming. Although the capture and handling of the PMJM by 
permitted researchers has resulted in unintentional mortalities, levels 
of take associated with scientific collection are very small and do not 
rise to a level that would affect populations of the subspecies. It 
follows that levels of take associated with scientific collection would 
not likely increase should we remove the protections of the Act. 
Furthermore, we have no information to indicate that collection for 
scientific or educational reasons is likely to become a significant 
threat to the subspecies, even if the protections afforded the 
subspecies under Colorado and Wyoming State laws were removed (see our 
discussion below under Factor D). Therefore, we determine that 
overutilization for commercial, recreational, scientific, or 
educational purposes is not a threat to the PMJM.

Factor C. Disease or Predation

    At the time of listing, we had no evidence of disease causing 
significant impacts to the PMJM (63 FR 26517, May 13, 1998). At this 
time, we have no additional evidence that any disease or parasite has 
caused a significant impact to the subspecies. Although

[[Page 31700]]

relationships between plague and North American rodents are poorly 
understood, plague may interact synergistically with other natural and 
human-induced disturbances, thereby increasing risk of local 
extirpation and rangewide extinction (Biggins and Kosoy 2001, p. 913). 
Although plague has not been documented in the PMJM, Pague and Grunau 
(2000, p. 19) considered disease to be a potentially high-priority 
issue for the subspecies. They cited a lack of information regarding 
immunological resistance of the PMJM to plague and other diseases. The 
researchers also noted that small, isolated populations could be 
especially vulnerable to effects of disease.
    In 1998, we evaluated potential predators of the PMJM whose 
densities could increase in the suburban or rural environment, 
including striped skunk (Mephitis mephitis), raccoon (Procyon lotor), 
and the domestic cat (Felis catus) (63 FR 26517, May 13, 1998). The 
increased impacts of native and exotic predators that accompany rural 
development can affect PMJM's viability (Hansen et al. 2005, p. 1899). 
We noted that free-ranging domestic cats and feral cats presented a 
problem to PMJM populations in habitats near human development. Where 
generalist predator populations increase through human land uses, they 
may contribute to the loss or decrease of the PMJM.
    Proponents of new residential developments near PMJM habitats are 
generally receptive to instituting prohibitions on free-ranging cats 
and dogs (Canis domesticus) when negotiating minimization measures 
through section 7 of the Act. However, enforcement is often through 
covenants administered by homeowners' associations, with uncertain 
success. Additionally, introduction of nonnative bullfrogs (Rana 
catesbeiana) in Colorado has resulted in predation on the PMJM (Trainor 
2004, p. 58). However, we have no information to suggest that predation 
from bullfrogs has affected PMJM populations.
    While uncertainties remain regarding disease and predation, we 
believe the best available scientific and commercial data suggest that 
disease is most likely to affect only small and fragmented PMJM 
populations. Additionally, increases in predation will likely only 
contribute to the reduction, fragmentation, and loss of PMJM 
populations when such populations are exposed to increased human 
presence. As noted under Factor A, increased human presence is expected 
to be more significant along the Front Range of Colorado or surrounding 
towns or cities in Wyoming, where predation may have a more of an 
effect than in rural areas. If the PMJM were to be delisted, covenants 
that address PMJM predation by domestic pets would be less likely to be 
enacted or enforced. Therefore, we conclude that disease is currently 
not a threat to the PMJM. However, when analyzed cumulatively with 
increases in commercial and residential development, as discussed under 
Factor A, predation by human-associated predators may be a threat to 
the PMJM.

Factor D. Inadequacy of Existing Regulatory Mechanisms

    The Act requires us to examine the adequacy of existing regulatory 
mechanisms with respect to existing and foreseeable threats that may 
affect PMJM. The existing regulatory mechanisms were found to be 
inadequate to protect the PMJM from the threats identified at the time 
of listing (63 FR 26517, May 13, 1998). Since it was listed as 
threatened, the Act has been and continues to be the primary Federal 
law that affords protection to PMJM. As explained below, the Service 
uses sections 7, 9, and 10 of the Act to assist in the conservation of 
the PMJM.
    Section 7(a)(1) of the Act requires all Federal agencies to utilize 
their authorities in furtherance of the purposes of the Act by carrying 
out programs for the conservation of endangered and threatened species. 
Section 7(a)(2) of the Act requires Federal agencies to ensure that 
actions they fund, authorize, or carry out do not ``jeopardize'' the 
continued existence of a listed species or result in the destruction or 
adverse modification of habitat in areas designated by the Service to 
be critical. Critical habitat has been designated for the PMJM. A 
jeopardy determination is made for a project that is reasonably 
expected, either directly or indirectly, to appreciably reduce the 
likelihood of both the survival and recovery of a listed species in the 
wild by reducing its reproduction, numbers, or distribution (50 CFR 
402.02). A project may receive a non-jeopardy determination, documented 
in a biological opinion, if it includes reasonable and prudent measures 
that minimize the extent of impacts to listed species associated with a 
project.
    Section 9 of the Act and Federal regulations pursuant to section 
4(d) of the Act prohibit the ``take'' of federally listed wildlife. 
Section 3(18) defines ``take'' to mean ``to harass, harm, pursue, hunt, 
shoot, wound, kill, trap, capture, or collect, or to attempt to engage 
in any such conduct.'' Service regulations (50 CFR 17.3) define 
``harm'' to include significant habitat modification or degradation 
which actually kills or injures wildlife by significantly impairing 
essential behavioral patterns, including breeding, feeding, or 
sheltering. ``Harassment'' is defined by the Service as an intentional 
or negligent action that creates the likelihood of injury to wildlife 
by annoying it to such an extent as to significantly disrupt normal 
behavioral patterns which include, but are not limited to, breeding, 
feeding, or sheltering. The Act provides for civil and criminal 
penalties for the unlawful taking of listed species.
    Listing the PMJM provided a variety of protections within areas 
under Federal jurisdiction and the conservation mandates of section 7 
for all Federal agencies. Since it was first listed in 1998, we have 
consulted and coordinated with multiple Federal agencies regarding the 
effects of proposed actions on the PMJM. For example, the USFS 
consulted and coordinated with us on more than 80 projects regarding 
the effects of recreation, forestry, or transportation projects 
occurring on federally owned National Forests. The U.S. Army Corps of 
Engineers has consulted and coordinated with us on more than 320 
projects regarding various impacts to PMJM and its habitat associated 
with commercial and residential developments, mining, or other 
activities impacting jurisdictional wetlands or waters. Additionally, 
the Federal Highway Administration coordinated and consulted with us on 
more than 262 projects regarding the effects of various transportation 
related activities to PMJM and its habitat. If the PMJM were not 
listed, these protections would not be provided. Thus, we must evaluate 
whether other regulatory mechanisms would provide adequate protections 
absent the protections of the Act.

National Environmental Policy Act (NEPA)

    All Federal agencies must comply with the NEPA of 1970 (42 U.S.C. 
4321 et seq.) for projects they fund, authorize, or carryout. The 
Council on Environmental Quality's regulations for implementing NEPA 
(40 CFR parts 1500-1518) state that agencies shall include a discussion 
on the environmental impacts of the various project alternatives 
(including the proposed action), any adverse environmental effects that 
cannot be avoided, and any irreversible or irretrievable commitments of 
resources involved (40 CFR part 1502). NEPA does not regulate 
activities that might affect

[[Page 31701]]

the PMJM, but does require full evaluation and disclosure of 
information regarding the effects of contemplated Federal actions on 
sensitive species and their habitats. It also does not require 
minimization or mitigation measures by the Federal agency involved. 
Therefore, Federal agencies may include conservation measures for the 
PMJM as a result of the NEPA process, but such measures would be 
voluntary in nature and are not required by the statute. Absent the 
listing of the PMJM, we would expect Federal agencies to continue to 
meet the procedural requirements of NEPA for their actions. However, as 
explained above, NEPA does not itself regulate activities that might 
affect the PMJM or its habitat

Clean Water Act (CWA)

    The CWA (33 U.S.C. 1251 et seq.) protects rivers and streams of the 
United States. The CWA establishes the basic structure for regulating 
discharges of pollutants into the waters of the United States and 
regulating quality standards for surface waters. The CWA's general goal 
is to ``restore and maintain the chemical, physical, and biological 
integrity of the Nation's waters'' (33 U.S.C. 1251 (a)). When 
practicable, section 404 of the CWA generally requires avoidance, 
minimization, and mitigation of adverse impacts associated with filling 
jurisdictional wetlands and waters of the United States. Human impacts 
to jurisdictional wetlands may be permitted when alternatives that 
would avoid wetlands are found not to be practicable. Section 404 of 
the CWA does not apply to non-jurisdictional waters or wetlands. In 
these cases, activities affecting these waters or wetlands would not 
require Federal permits under section 404 of the CWA. More importantly, 
section 404 of the CWA provides no comparable safeguards for non-
jurisdictional riparian and upland habitat areas important to the PMJM.
    Section 303 of the CWA establishes the water quality standards and 
total maximum daily load (TMDL) programs. Water quality standards are 
set by States, Territories, and Tribes. They identify the uses for each 
waterbody, for example, drinking water supply, contact recreation 
(swimming), and aquatic life support (fishing), and the scientific 
criteria to support that use. A TMDL is a calculation of the maximum 
amount of a pollutant that a waterbody can receive and still meet water 
quality standards, and an allocation of that amount to the pollutant's 
sources. Colorado and Wyoming are required under section 305(b) of the 
CWA to complete an assessment of their surface waters. From this 
assessment, a CWA 303(d) list of impaired water bodies is developed. 
These are waters that are not currently meeting their designated uses 
because of impairments to the waters.
    Through the CWA, the Environmental Protection Agency (EPA) 
encourages communities, watershed organizations, and local, State, 
tribal, and Federal environmental agencies to develop and implement 
watershed plans to meet water quality standards and protect water 
resources. These plans can include measures that will help protect 
riparian areas and may in some cases provide benefits to the PMJM. For 
example, in Wyoming, the Crow Creek Watershed Plan coordinated by the 
Laramie County Conservation District includes recommendations to 
protect riparian habitat because of the benefits to water quality (LCCD 
2007, p. 1). The plan's amendment also recognizes suitable PMJM 
habitats within the Pole Mountain Area and encourages proponents to 
recognize and comply with the Act's protections (LCCD 2007, pp. 17, 
21). While these efforts to improve water quality have the potential to 
improve or protect riparian habitat, the measures are typically not 
mandatory, and such watershed planning efforts do not encompass the 
range of the subspecies. Thus, the CWA provides only limited protection 
of habitats utilized by the PMJM and is not capable of substantially 
reducing threats to individual PMJM populations or to the subspecies as 
a whole.

National Forest Management Act (NFMA)

    The NFMA (16 U.S.C. 1600 et seq.) requires the USFS to prepare 
management plans for each National Forest. These management plans 
address management issues such as recreation, range, timber, biological 
diversity, and economic and social factors. On lands administered by 
the USFS, the PMJM's threatened status under the Act promotes USFS 
policies that contribute to its protection and recovery. Of the three 
National Forests supporting PMJM populations, the Medicine Bow-Routt 
National Forest has a forest management plan that includes standards 
and guidelines specific to conservation of the PMJM. The Arapahoe-
Roosevelt National Forest and the Pike-San Isabel National Forest have 
forest plans that predate the listing of the PMJM (Warren 2007). If 
delisted, the USFS could potentially continue to recognize the PMJM as 
a subspecies warranting conservation concern with some degree of 
conservation priority. However, without the Act's protections, there is 
no guarantee that Federal agencies would continue to prioritize PMJM 
conservation.

Sikes Act Improvement Act (Sikes Act)

    The Sikes Act of 1997 (16 U.S.C. 670) authorizes the Secretary of 
Defense to develop cooperative plans with the Secretaries of 
Agriculture and the Interior for natural resources on public lands. The 
Sikes Act requires Department of Defense installations to prepare 
Integrated Natural Resources Management Plans (INRMPs) that provide for 
the conservation and rehabilitation of natural resources on military 
lands consistent with the use of military installations to ensure the 
readiness of the Armed Forces. INRMPs incorporate, to the maximum 
extent practicable, ecosystem management principles and provide the 
landscape necessary to sustain military land uses. INRMPs are developed 
in coordination with the State and the Service, and are generally 
updated every 5 years. Although an INRMP is technically not a 
regulatory mechanism, because its implementation is subject to funding 
availability, it is an important guiding document that helps to 
integrate natural resource protection with military readiness and 
training
    The Air Force Academy (Academy) in El Paso County, Colorado, has an 
INRMP in place, a conservation and management plan, and a programmatic 
consultation under section 7 of the Act, which provide guidance for Air 
Force management decisions for certain activities that may affect the 
PMJM. Research on the PMJM is ongoing at the Academy, and the 
conservation and management plan is designed to be updated as new 
information is collected. Warren Air Force Base in Laramie County, 
Wyoming, also has an INRMP and a conservation and management plan, 
which addresses the PMJM, even though the base may only support the 
western jumping mouse. These plans adequately reduce threats to the 
PMJM on these bases. Both plans are updated every 5 years, but the 
emphasis given to conservation of the PMJM may decline in the future if 
the subspecies were to be delisted.

National Wildlife Refuge System Improvement Act

    The National Wildlife Refuge System Improvement Act of 1997 and the 
Fish and Wildlife Service Manual (601 FW 3, 602 FW 3) require 
maintaining biological integrity and diversity, comprehensive 
conservation planning for each refuge, and set standards to ensure that 
all uses of refuges are compatible with their purposes and the

[[Page 31702]]

Refuge System's wildlife conservation mission. The comprehensive 
conservation plans (CCP) address conservation of fish, wildlife, and 
plant resources and their related habitats for a refuge, while 
providing opportunities for compatible wildlife-dependent recreation 
uses. An overriding consideration reflected in these plans is that fish 
and wildlife conservation has first priority in refuge management, and 
that public use be allowed and encouraged as long as it is compatible 
with, or does not detract from, the Refuge System mission and refuge 
purpose(s).
    Although survey efforts for PMJMs at National Wildlife Refuges 
(NWRs) have been limited, trapping surveys documented PMJM at the Rocky 
Flats NWR near Boulder, Colorado, and a jumping mouse at Hutton Lake 
NWR near Laramie, Wyoming. However, genetic analysis later determined 
that the mouse field-identified as a PMJM at Hutton Lake NWR was 
actually a western jumping mouse (Ramey et al. 2005, Appendix 3). 
Therefore, the capture at Rocky Flats NWR represents the only 
documentation of a PMJM on an NWR. The Service continues to manage 
Rocky Flats NWR in a manner consistent with conservation of the PMJM. 
Management of Rocky Flats or other NWRs that may support PMJM or its 
habitats is unlikely to change if the PMJM were to be delisted.

Fish and Wildlife Coordination Act (FWCA)

    The FWCA requires that proponents of Federal water development 
projects, including those involving stream diversion, channel 
deepening, impoundment construction, and/or general modifications to 
water bodies, consider their impacts to fish and wildlife resources. 
FWCA also requires that impacts to water bodies be offset through 
mitigation measures developed in coordination with the Service and the 
appropriate State wildlife agency. Therefore, FWCA may provide some 
protection for the PMJM and its habitat through avoidance and 
minimization measures that may be incorporated into Federal projects. 
Therefore, the FWCA is an adequate regulatory mechanism to address 
threats within the confines of its applicability, but its applicability 
is limited. The minor benefits provided by FWCA would continue in the 
absence of the Act's protection.
    State Protections: Under the nongame provisions of the CPW 
Regulations (Chapter 10, Article IV) the PMJM currently may only be 
taken legally by permitted personnel for educational, scientific, or 
rehabilitation purposes. Wyoming classifies meadow jumping mice as a 
``nongame species'' under section 11 of chapter 52 (Nongame Wildlife) 
of the Wyoming Game and Fish Commission regulations. As in Colorado, 
these regulations protect the PMJM from takings and sales by allowing 
the issuance of permits only for the purpose of scientific collection. 
As described under Factor B, overutilization for commercial, 
recreational, scientific, or educational purposes is not now, nor is it 
likely to become, a significant threat to the subspecies, even if the 
protections afforded the subspecies under Colorado and Wyoming laws 
were removed. However, classification of the PMJM as a nongame species 
in Colorado or Wyoming, which prohibits non-scientific collection, does 
not address threats associated with habitat loss and modification as 
described under Factor A.
    Numerous State lands (CPW and WFGD lands, State Park lands, State 
Land Board lands) and mitigation properties (such as those of the 
Colorado Department of Transportation) would continue to provide a 
measure of protection for the PMJM, should it be delisted. While some 
of these conservation properties may have management specifically 
designed to preserve and enhance PMJM habitat, others are managed more 
generally for wildlife habitat, for human recreation, or for multiple 
uses.
    Local Protections: At the time of listing, we noted that, while a 
myriad of regional or local regulations, incentive programs, and open-
space programs existed, especially in Colorado, few specifically 
protected the PMJM or its habitat from inadvertent or intentional 
adverse impacts (63 FR 26517, May 13, 1998). Many local regulations 
create a process of site-plan review that ``considers'' or 
``encourages'' conservation of wildlife, wetlands, and other natural 
habitats, but have no mandatory measures requiring avoidance or 
mitigation of impacts. Effectiveness of local regulations in 
maintaining naturally functioning riparian corridors varies greatly 
depending on how these apparently flexible regulations are implemented.
    Following listing under the Act, development and other projects in 
and near PMJM habitat have received increased scrutiny from local 
jurisdictions, often in coordination with the Service. Open-space 
acquisitions and easements also have taken the PMJM and its habitat 
into account. It is not clear what level of interest in PMJM 
conservation would continue following delisting. Local governments 
would likely relax review procedures for projects in known or suspected 
PMJM habitat. Beyond the direct impact to PMJM habitat, secondary 
impacts of development (including increased recreational use, altered 
flow regimes and groundwater levels, and increased domestic predators) 
are unlikely to be adequately addressed. While certain local 
regulations are designed to conserve wetlands or floodplains on private 
lands, it is unlikely they would effectively control land uses 
(grazing, mowing, cutting, and burning) that may affect the hydrology, 
vegetation, and hibernacula sites on which the PMJM depends. The 
adequacy of such protective measures is more important within Colorado 
than Wyoming given the intense development pressures in the Colorado 
counties where the PMJM occurs.
    Douglas County, Colorado, owns 14 properties that encompass 24 km 
(15 mi) of stream and associated riparian habitats potentially 
beneficial to the PMJM (Matthews 2004). Of Douglas County streams on 
non-Federal property within the county-mapped Riparian Conservation 
Zone, 105 km (65 mi), or 23 percent, are under some form of permanent 
protection (Matthews 2004), including 77 km (48 miles) on Plum Creek 
and its tributaries and 25 km (16 mi) on Cherry Creek and its 
tributaries (Matthews 2008, Douglas County HCP). However, occurrence of 
the PMJM on many of these properties has not been extensively 
documented. For example, while there are 23.4 km (14.5 mi) of mapped 
riparian corridors on the large Greenland Ranch conservation property, 
the presence of the PMJM has been documented at only two sites. Future 
conservation efforts to augment protected areas and to link protection 
over large expanses of connected streams in Douglas County could 
contribute greatly to maintaining secure PMJM populations in the Upper 
South Platte and Middle South Platte-Cherry Creek drainages. If the 
PMJM were delisted, management priorities on protected lands and the 
direction of future conservation efforts would likely change in the 
absence of formalized agreements or plans.
    Larimer County has acquired or secured easements to considerable 
lands, including some properties under the Laramie Foothills Project, 
in partnership with The Nature Conservancy, the City of Fort Collins, 
and the Legacy Land Trust. While conservation efforts have increased, 
especially in the Livermore Valley, residential development remains the 
largest threat to the PMJM in the county (Pague 2007). The extent to 
which

[[Page 31703]]

PMJM populations are supported by these properties, the fate of 
remaining private lands in the North Fork and Cache La Poudre River and 
its tributaries, and the ability to link conservation lands and 
traditional agricultural lands supporting the PMJM along stream reaches 
are key to protecting the potentially large PMJM population thought to 
exist in this area.
    The City of Boulder, Boulder County, and Jefferson County have 
extensive lands protected under their open-space programs. While the 
extent of known PMJM occurrences in these counties is limited compared 
to that documented in Larimer and Douglas Counties, known populations 
exist on open space protected from residential and commercial 
development.
    Overall, the CPW examined land ownership on over 58,000 ha (143,000 
ac) in Colorado that they considered occupied by the PMJM. The CPW 
estimated the area of PMJM occupancy in Colorado by buffering habitats 
around documented capture locations. The CPW's analysis estimated that 
approximately 45 percent of the PMJM occupied area occurs on protected 
lands, such as those in public ownership, land trusts, or conservation 
easements (Nesler 2008). However, the trapping surveys used in this 
buffer analysis disproportionally targeted public lands or sites of 
proposed development, due largely to ease of accessibility. Therefore, 
the 45 percent statistic may overestimate the actual amount of PMJM 
habitat that occurs on protected lands. Although this percentage 
suggests meaningful progress toward recovery of the subspecies in 
Colorado, it does not indicate that protected status adequately reduces 
threats to the PMJM.
    At the request of the Service, in 2008, the CPW conducted a similar 
evaluation for specific areas we consider of high importance to PMJM 
conservation in Colorado. These included units designated as PMJM 
critical habitat and additional units of proposed critical habitat that 
were excluded from the 2010 final designation (75 FR 78430, December 
15, 2010) due to ongoing conservation efforts. While our proposal and 
designation of critical habitat units focused on lands in public 
ownership, which may bias the results, examination of these areas 
provides some perspective into potential protections in place in 
Colorado. Public lands, land trusts, or conservation easements comprise 
approximately 51 percent of the critical habitat.
    While estimated percentages of lands in protected ownership 
categories are encouraging, and these lands may be critical to the 
PMJM's recovery, existing protections on these lands do not fulfill 
preliminary draft recovery plan objectives, nor do they assure the 
future viability of these PMJM populations. Therefore, these local 
regulatory mechanisms on protected lands inadequately reduce threats to 
the PMJM at this time.
    As discussed under Factor A, fragmentation of PMJM habitat and 
resulting impacts on the future security of PMJM populations is a 
significant concern. Even in drainages where lands in public ownership 
or private properties dedicated to conservation are relatively 
extensive, development of intervening private lands is likely to 
fragment habitat and may impact PMJM populations.
    Many of the public ownership areas are relatively high-elevation, 
montane headwater habitats. As discussed previously, such areas may 
have less suitable habitat that supports lower density PMJM populations 
than at plains and foothill sites. Additionally, as elevation 
increases, there is an increased occurrence of the western jumping 
mouse. Overlap in ranges of the two species seems greatest in Wyoming, 
where a more gradual rise from the plains to the Laramie Mountains 
allows for a greater extent of mid-range elevations occupied by both 
species. Thus, in order to rely upon the contribution that protection 
or public ownership of these higher elevation areas provides to the 
long-term security of the PMJM, positive identification to species and 
localized demographic data would be required.
    Finally, public ownership may not preclude properties from human 
development, other land uses, or management priorities that may affect 
the PMJM or its habitat. Although public lands may be protected and 
managed in a manner compatible with the needs of the PMJM, activities 
off site may indirectly affect the PMJM. Most prominent among these 
secondary impacts are those resulting from changes in stream flow 
regimes. Recent evidence suggests secondary impacts from development of 
private land upstream from the Academy (proposed as critical habitat 
Unit A1, now designated as critical habitat Unit 11) threaten the 
integrity of habitat present and the PMJM population it supports 
(Schorr 2012a, p. 1277).
    In Wyoming, as would be expected in areas where development 
pressures are substantially less, the regional and local regulations 
affecting PMJM habitat appear to be less extensive than in the Colorado 
portion of its range. Currently Albany, Laramie, Converse, and Platte 
Counties in Wyoming have zoning regulations, including the regulation 
of subdivision development (USFWS 2012b). These and other local 
protections provide some protection of water resources and floodplains 
and reduce soil erosion. However, overall, there are few local 
regulatory protections in the Wyoming portion of the PMJM's current 
range.
    Summary of Factor D: In the absence of the Act's protective 
measures, Federal conservation efforts for the PMJM would largely be 
limited to Federal properties, where the subspecies could be maintained 
as a priority or sensitive subspecies and conserved through existing or 
future management plans. However, in the absence of the Act's 
protections, there are no guarantees at this time that Federal agencies 
would continue to recognize PMJM as sensitive or in need of protection.
    If retained as a non-game species, State regulations in both 
Colorado and Wyoming would continue to regulate purposeful killing of 
the PMJM, which we do not view as a significant concern as summarized 
under Factor B. State and local regulations do little to conserve the 
PMJM or its habitat on private lands. Public land holdings, 
conservation easements, and other conservation efforts, past and 
future, could support the PMJM on specific sites. The extent and 
pattern of conservation efforts in relation to PMJM's distribution, and 
the appropriate management of PMJM habitat, would largely dictate the 
long-term viability of PMJM populations.
    As described in the preliminary draft recovery plan (USFWS 2003b), 
no large populations and few medium-sized populations are known to 
exist on contiguous stream reaches that are secure from development. 
Management plans that specifically address threats to the PMJM are few, 
and management priorities would likely change if we were to delist the 
subspecies. Much of the intervening private lands would likely be 
subject to development in the future (this issue is described in more 
detail under Factor A above). If we were to delist the subspecies, 
given current and projected levels of population protections, we 
believe that existing regulatory mechanisms would not be adequate to 
mitigate the impacts of identified threats to most PMJM populations in 
Colorado and in the vicinity of Cheyenne, Wyoming.

Factor E. Other Natural or Manmade Factors Affecting the Subspecies' 
Continued Existence

    The PMJM is susceptible to other natural or manmade factors, 
including

[[Page 31704]]

impacts from floods, wildfire, drought, invasive weeds and weed control 
programs, pesticides and herbicides, and secondary impacts associated 
with human-caused development (63 FR 26517, May 13, 1998). For most of 
these factors, we have little more information now than we had at the 
time of listing. Additional concerns that were not considered at the 
time of listing include the potential for competition between the PMJM 
and the western jumping mouse, small population sizes, and future 
effects of changing climate, including its potential to augment threats 
from fire and drought. We evaluate each of these factors below.
    Floods: Floods are natural components of the Wyoming and Colorado 
foothills and plains. PMJMs and their habitats evolved under historic 
flood regimes, so populations and habitats naturally respond to 
flooding events. While floods may affect PMJM populations by killing 
individuals and destroying riparian and adjacent upland habitats, the 
effects to vegetation are usually temporary. Vegetation typically 
reestablishes quickly after floods, although larger floods may delay 
recovery. Normal flooding may help maintain the vegetative communities 
that provide suitable habitat for the PMJM.
    However, manmade increases in impervious surfaces and the loss of 
vegetation caused by human activities or catastrophic wildfire can 
result in an increased frequency and severity of flood events. Flooding 
is often a byproduct of wildfires and may act synergistically to alter 
the composition and structure of riparian ecosystems for many years 
(Ellis 2001, p. 159). Therefore, extreme floods may prevent the re-
establishment of the PMJM's favored riparian vegetation, forcing mice 
to disperse until habitats recover. While an extreme flood can 
eliminate an entire PMJM population in an affected stream reach, floods 
are less likely to eliminate the PMJM across an entire drainage system 
if populations extend into side tributaries or headwater unaffected by 
the flood. Therefore, maintaining the connectivity of riparian habitats 
between stream reaches is crucial to maintaining the security of PMJM 
populations faced with an increased incidence of flooding.
    At this time, we lack information to conclude that flooding alone 
is a threat to the PMJM. However, flooding will increase under a 
warming climate (Milly et al. 2002, p. 514), with extreme floods 
potentially becoming increasingly problematic throughout the PMJM's 
range. Additionally, floods could develop into more a substantial 
threat as more human development increases impervious surfaces and 
removes vegetation.
    Wildfire: Over the last 50 years, more dry summers, more human-
caused fires, and a history of fire suppression have increased the 
frequency, size, and severity of wildfires (Auclair and Bedford, 1994, 
p. 249; Sackett et al., 1994, p. 115; Swetnam and Betancourt, 1998, p. 
3128; Ellis, 2001, p. 160). In the western United States, large 
wildfire activity increased in the mid-1980s, marked by higher large-
wildfire frequency, longer wildfire durations, and longer wildfire 
seasons (Westerling et al. 1996, p. 940). In Colorado and Wyoming, 
temperatures and numbers of wildfires have increased since 1970 
(Climate Central 2012, p. 4). Rising spring and summer temperatures, 
along with shrinking snowpacks, increased the risk of wildfires in most 
parts of the West, with global climate change likely to further 
increase the frequency of wildfires throughout the region in the future 
(Westerling et al. 1996, p. 940; Climate Central 2012, p. 1). Satellite 
data and climate models predict an increase in fire risk across the 
United States by 2050, and drier conditions and more extreme fire 
events augment the risk (Hansen and Gran 2012, p. 1). Within the PMJM's 
range, climate models predict that wildfires will be more frequent and 
more severe, potentially burning 4 to 5 times more area, even when the 
models account for uncertainty associated with precipitation (Climate 
Central 2012, p. 9). Extreme fire years, such as 2002 with the Hayman 
Fire and 2012 with the High Park and Hewlett Fires, may occur 2 to 4 
times more per decade than they do currently by 2050 (Hansen and Gran 
2012, p. 1).
    As wildfires burn, the intense heat, combustion gases, and 
consumption of organic material kills or displaces animals and may 
dramatically alter the structure and composition of habitats (Quinn 
1979, p. 126). Small mammals die during wildfires from burns, 
asphyxiation, heat stress, overexertion, stampedes, and predation 
(Kaufman et al. 1990, p. 47). Wildfires may also interrupt the breeding 
cycles and movements of surviving animals, while affecting the quality 
and quantity of food, the availability of nest sites, the pressures of 
predation and competition, and the incidence of disease and parasites 
(Kaufman et al. 1990, p. 47). Although riparian plants do not depend on 
fire for regeneration, wildfire influences these habitats by changing 
their structure and composition (Ellis 2001, p. 159). Wildfire may 
promote the invasion of nonnative plants, which when established, alter 
fire regimes, increase water use, and change the structure of the 
native community (Fornwalt et al. 2003, p. 515). Additionally, where 
wildfires destroy vegetation and change soil properties, they alter 
hydrology and sediment-transport processes, which increase erosion and 
the deposition of sediment (Verdin et al. 2012, pp. 1-2). Because these 
factors may affect the PMJM during or following a wildfire, Pague and 
Granau (2000) considered catastrophic fire to be a high-priority issue.
    Wildfires burn riparian habitats, although the fires within these 
ecosystems may be less frequent or less intense than the adjoining 
uplands. Because the plant species, hydrology, microclimates, and fuel 
characteristics of riparian ecosystems differ from adjacent uplands, 
riparian areas possess different fire environments, fire regimes, and 
fire properties (Dwire and Kaufmann 2003, pp. 61, 71). Compared to 
upland habitats, moist fuels and the rapid decomposition of organic 
litter lessen the frequency of wildfires within riparian habitats 
(Busch 1995, p. 259). Generally, fire frequencies and intensities are 
lower in riparian habitats than in adjoining uplands (Dwire and 
Kaufmann 2003, pp. 61, 71). In Colorado for example, the Hayman Fire of 
2002 burned significantly cooler in riparian areas than upslope areas, 
although burn intensities correlated positively to the burn intensity 
of the surrounding watershed (Decker et al. 2006, pp. 1, 3). 
Additionally, riparian habitats along smaller streams burned hotter, 
like the uplands, but riparian habitats along larger streams 
experienced cooler burns (Decker et al. 2006, pp. 1, 3). Wildfires in 
PMJM's riparian habitats during Colorado's High Park Fire of 2012 
exhibited similar fire characteristics, where light, wet fuels either 
slowed the burn at the riparian zone or restricted burning to 
herbaceous, understory vegetation (Oberlag 2012, p. 2).
    Periodic, low-severity wildfires may actually maintain PMJM 
habitats by removing understory fuels and promoting the regrowth of 
willows and other riparian vegetation. In the tallgrass prairies of 
Illinois, meadow jumping mouse populations displayed a positive 
response to fire in one study, but no response to fire in a second 
study (Kaufman et al. 1990, p. 55). Alternatively, in Colorado, 
trapping and telemetry data indicated that PMJMs did not enter burned 
habitats for at least 3 years after the Hayman Fire (Hansen 2006, pp. 
163-164). Wildfires, especially those with high-severity burns, may 
render habitats unsuitable to

[[Page 31705]]

the PMJM for many years. If left untreated, nonnative, invasive plants 
may alter the post-fire dynamics of riparian areas 50 to 100 years 
after a wildfire (Graham 2003, pp. 22-23).
    Although wildfires within riparian habitats may be less frequent or 
less intense than burns in uplands, wildfires have burned PMJM habitats 
throughout the subspecies' range. Colorado's High Park Fire of 2012 
burned PMJM habitats lightly, with burned herbaceous vegetation 
expected to regrow in 1 to 3 years (Oberlag 2012, p. 2). Similarly, the 
majority of PMJM habitats burned by Colorado's Hewlett Fire of 2012 and 
Crystal Fire of 2011 experienced low-intensity burns, with some loss of 
herbaceous vegetation (Oberlag 2011, p. 1; Oberlag 2012, pp. 1-2). 
Comparatively, the Fourmile Canyon Fire in Colorado during the summer 
of 2010 moderately and severely burned approximately 37 percent of 
potential PMJM habitats within the fire perimeter (Baker 2010, p. 2). 
Severe, high-intensity burns also occurred in PMJM habitats during 
2002. During the early summer of 2002, the Hayman and Schoonover fires 
in Colorado burned over 3,000 ha (7,500 ac) of potential PMJM habitat, 
or approximately 20 percent of the potential habitat within the 
boundaries of the Pike National Forest (Elson 2003, p. 2). 
Additionally, the Hayman Fire severely burned approximately 342 ha (844 
ac) of proposed critical habitat for the PMJM, which prompted the 
removal of several proposed areas from the final 2003 critical habitat 
designation (68 FR 37276, June 23, 2003).
    Superimposing PMJM's critical habitat and occupied habitats with 
perimeters of wildfires provides estimates of PMJM habitats potentially 
burned by wildfires over the last 12 years. Burn area perimeter 
analyses for wildfires collected since 2000 calculate that wildfires 
potentially burned approximately 2,376 ha (5,873 ac), or 17 percent, of 
designated PMJM critical habitat in Colorado (USFWS 2013, p. 1). 
Perimeter datasets also estimate that Colorado wildfires potentially 
burned approximately 4,150 ha (10,254 ac), or approximately 10 percent, 
of trapped habitats identified as occupied by PMJM (USFWS 2013, p. 1). 
In Wyoming, burn area perimeter datasets collected since 2000 identify 
three wildfires that potentially burned PMJM habitats: The Hensel and 
Reese Mountain Fires of 2002 and the Arapaho Fire of 2012 (USFWS 2013, 
p. 1). However, none of these wildfires have likely impacted areas 
formerly designated as PMJM critical habitat in Wyoming and we lack an 
estimate for occupied habitats in Wyoming in order to approximate 
burned habitats (USFWS 2013, p. 1). Although these analyses do not 
account for variance in burn severity within the perimeter of the 
wildfire, they illustrate that wildfires potentially burned more than 
17 percent of PMJM's designated critical habitats in Colorado over the 
last 12 years. The perimeter analyses also do not consider any 
auxiliary effects of wildfire, such as flooding, erosion, or 
sedimentation, that may affect habitats within or outside the burn area 
perimeter, so these estimations may underestimate actual impacts to 
PMJM habitats. Additionally, these perimeter datasets may not capture 
all wildfires that burned within PMJM habitats.
    Wildfires continue to affect the PMJM and its habitats. In the 
future, a warmer, drier climate will increase the frequency and 
intensity of wildfires throughout the PMJM's range. Therefore, 
wildfires continue to be a threat to the PMJM.
    Drought: Like wildfire and floods, drought is another factor that 
negatively affects the PMJM. Drought lowers stream flows and the 
adjacent water table, in turn impacting the PMJM's riparian habitats. 
Frey (2005, p. 62) found that drought had a major influence on the 
status and distribution of another subspecies, the New Mexico jumping 
mouse in New Mexico. In 2002, a year with regional drought conditions, 
Bakeman (2006, p. 11) failed to capture any PMJMs at two sites where he 
had previously documented substantial populations. While PMJM 
populations have coexisted with periodic drought, significant increases 
in frequency or severity of drought, as is predicted as a consequence 
of global climate change throughout the subspecies' range, could impact 
the persistence of PMJM. Models predict increased global aridity, with 
severe and widespread droughts over the next 30 to 90 years resulting 
from decreased precipitation and increased evaporation (Dai 2012, p. 
52). The effects of drought will likely be a more significant factor 
for small and fragmented populations, while large populations with 
substantial tracts of suitable habitat with steady hydrologic regimes 
will be better isolated from the effects of drought. However, drought 
may exacerbate adverse impacts of cattle grazing on PMJM habitat as 
livestock seek forage in riparian habitats. Additionally, climate 
change and the promotion of noxious weeds may exacerbate the effects of 
drought. Therefore, drought is a threat to the PMJM.
    Nonnative plants: Invasive, noxious plants can encroach upon a 
landscape, displace native plant species, form monocultures of 
vegetation, and may negatively affect food and cover for the PMJM. The 
control of noxious weeds may entail large-scale removal of vegetation 
and mechanical mowing operations, which also may affect the PMJM. The 
tolerance of the PMJM for invasive plant species remains poorly 
understood. Leafy spurge (Euphorbia esula) may form a monoculture, 
displacing native vegetation and thus reducing available habitat 
(Selleck et al. 1962; Pague and Grunau 2000, p. 1-18). Nonnative 
species including tamarisk, or saltceder (Tamarix ramosissima), and 
Russian olive (Elaeagnus angustifolia) may adversely affect the PMJM 
(Garber 1995, p. 16; Pague and Grunau 2000, p. 18). Existing special 
regulations at 50 CFR 17.40(1) exempt incidental take of the PMJM 
during the control of noxious weeds. This exemption recognizes that 
control of noxious weeds is likely to produce long-term benefits to the 
native vegetation of PMJM habitats.
    Although we lack information to conclude that nonnative plants are 
a threat to the PMJM, nonnative plants may become increasingly 
problematic as climate change and drought favor drought-tolerant 
species that alter the structure and function of riparian communities.
    Pesticides and Herbicides: The effect of point and non-point source 
pollution (sewage outfalls, spills, urban or agricultural runoff) that 
degrades water quality in potential habitats on the abundance or 
survival of the PMJM remains unclear. From an examination of their 
kidney structure, it is uncertain whether the PMJM requires drinking 
water from open water sources, or may obtain water exclusively through 
dew and food (Wunder 1998), which would influence its potential 
exposure to pollution. Likewise, it is unknown whether pesticides and 
herbicides, commonly used for agricultural and household purposes 
within the range of the PMJM, pose a threat to the PMJM directly, or 
through its food supply, including possible bioaccumulation of 
hazardous chemicals. Therefore, at this time we lack information to 
conclude that pesticides and herbicides are a threat to the PMJM.
    Secondary Impacts of Human Development: Human development creates a 
range of additional potential impacts (through human presence, noise, 
increased lighting, introduced animals, and the degradation of air and 
water quality) that could alter the PMJM's behavior, increase its 
levels of stress, and ultimately contribute to loss of vigor or death 
of individuals, and eventual extirpation of populations. Introduced 
animals associated with human development may displace, prey upon, or 
compete with the PMJM. Feral

[[Page 31706]]

cats and house mice were common in and adjacent to historical capture 
sites where the PMJM was no longer found (Ryon 1996, p. 26). While no 
cause-and-effect relationships were documented, the PMJM was 13 times 
less likely to be present at sites where house mice were found 
(Clippinger 2002, p. 104). As described under Factor A, the absence of 
the PMJM in portions of drainages where riparian habitat appears 
relatively favorable but human encroachment is pervasive, suggests a 
potential cause-and-effect relationship attributable to a variety of 
primary or secondary influences. Cumulative impacts from a variety of 
factors in addition to habitat loss and fragmentation may contribute to 
local extirpations.
    Instability of Small Populations: Colorado's Comprehensive Wildlife 
Conservation Strategy identifies ``scarcity'' as a threat to meadow 
jumping mice that may lead to inbreeding depression (CPW 2006, p. 102). 
Stochastic, or random, changes in a wild population's demography or 
genetics can threaten small populations (Brussard and Gilpin 1989, pp. 
37-48; Caughley and Gunn 1996, pp. 165-189). A stochastic demographic 
change in small populations, such as a skewed age or sex ratios (for 
example, a loss of adult females), can depress reproduction and 
increase the risk of extirpation. Isolation of populations, whether 
through habitat loss or fragmentation, may disrupt gene flow and create 
unpredictable genetic effects that could impact the persistence of PMJM 
populations in a given area. While the susceptibility of the PMJM to 
stochastic events has not been specifically researched, the documented 
tendency for PMJM population estimates to vary widely over time 
heightens concern for small and isolated populations. Within 
populations, periodic lows in numbers of PMJMs present more accurately 
reflect potential vulnerability than typical or average numbers 
present. Although many trapping efforts have targeted the PMJM in 
small, isolated reaches of apparently acceptable habitat, few have 
documented presence. Small, fragmented PMJM populations, including 
those fragmented in the future by human development, are likely to be 
unsustainable. Therefore, we conclude that the instability of small 
populations is a threat to the PMJM.
    Intraspecific Competition: The relative ranges, abundance, and 
relationship between the PMJM and the western jumping mouse are not yet 
clearly understood, especially in Wyoming. However, recent confirmation 
of extensive range overlap in Wyoming and the apparent predominance of 
the western jumping mouse in some southern Wyoming drainages with few 
or no recent records of PMJM provide reason for concern (Bowe and 
Beauvais 2012, p. 15). It is unclear whether western jumping mice are 
actively competing with PMJMs, affecting PMJM population size, and 
possibly limiting distribution, or if this distribution pattern is 
unrelated to their interaction. Additional study is needed to clarify 
these issues. Although questions remain, we do not have information to 
indicate that presence of the western jumping mouse and potential 
intraspecific competition currently constitutes a threat to the PMJM.
    Global Climate Change: Our analyses under the Act include 
consideration of ongoing and projected changes in climate. The terms 
``climate'' and ``climate change'' are defined by the Intergovernmental 
Panel on Climate Change (IPCC). The term ``climate'' refers to the mean 
and variability of different types of weather conditions over time, 
with 30 years being a typical period for such measurements, although 
shorter or longer periods also may be used (IPCC 2007a, p. 78). The 
term ``climate change'' thus refers to a change in the mean or 
variability of one or more measures of climate (e.g., temperature or 
precipitation) that persists for an extended period, typically decades 
or longer, whether the change is due to natural variability, human 
activity, or both (IPCC 2007a, p. 78).
    Scientific measurements spanning several decades demonstrate that 
changes in climate are occurring, and that the rate of change has been 
faster since the 1950s. Examples include warming of the global climate 
system, and substantial increases in precipitation in some regions of 
the world and decreases in other regions. (For these and other 
examples, see IPCC 2007a, p. 30; and Solomon et al. 2007, pp. 35-54, 
82-85). Results of scientific analyses presented by the IPCC show that 
most of the observed increase in global average temperature since the 
mid-20th century cannot be explained by natural variability in climate, 
and is ``very likely'' (defined by the IPCC as 90 percent or higher 
probability) due to the observed increase in greenhouse gas (GHG) 
concentrations in the atmosphere as a result of human activities, 
particularly carbon dioxide emissions from use of fossil fuels (IPCC 
2007a, pp. 5-6 and figures SPM.3 and SPM.4; Solomon et al. 2007, pp. 
21-35). Further confirmation of the role of GHGs comes from analyses by 
Huber and Knutti (2011, p. 4), who concluded it is extremely likely 
that approximately 75 percent of global warming since 1950 has been 
caused by human activities.
    Scientists use a variety of climate models, which include 
consideration of natural processes and variability, as well as various 
scenarios of potential levels and timing of GHG emissions, to evaluate 
the causes of changes already observed and to project future changes in 
temperature and other climate conditions (e.g., Meehl et al. 2007, 
entire; Ganguly et al. 2009, pp. 11555, 15558; Prinn et al. 2011, pp. 
527, 529). All combinations of models and emissions scenarios yield 
very similar projections of increases in the most common measure of 
climate change, average global surface temperature (commonly known as 
global warming), until about 2030. Although projections of the 
magnitude and rate of warming differ after about 2030, the overall 
trajectory of all the projections is one of increased global warming 
through the end of this century, even for the projections based on 
scenarios that assume that GHG emissions will stabilize or decline. 
Thus, there is strong scientific support for projections that warming 
will continue through the 21st century, and that the magnitude and rate 
of change will be influenced substantially by the extent of GHG 
emissions (IPCC 2007a, pp. 44-45; Meehl et al. 2007, pp. 760-764 and 
797-811; Ganguly et al. 2009, pp. 15555-15558; Prinn et al. 2011, pp. 
527, 529). (See IPCC 2007b, p. 8, for a summary of other global 
projections of climate-related changes, such as frequency of heat waves 
and changes in precipitation. Also see IPCC 2011(entire) for a summary 
of observations and projections of extreme climate events.)
    Various changes in climate may have direct or indirect effects on 
species. These effects may be positive, neutral, or negative, and they 
may change over time, depending on the species and other relevant 
considerations, such as interactions of climate with other variables 
(e.g., habitat fragmentation) (IPCC 2007, pp. 8-14, 18-19). Identifying 
likely effects often involves aspects of climate change vulnerability 
analysis. Vulnerability refers to the degree to which a species (or 
system) is susceptible to, and unable to cope with, adverse effects of 
climate change, including climate variability and extremes. 
Vulnerability is a function of the type, magnitude, and rate of climate 
change and variation to which a species is exposed, its sensitivity, 
and its adaptive capacity (IPCC 2007a, p. 89; see also Glick et al. 
2011, pp. 19-22). There is no single method for conducting such 
analyses that applies to

[[Page 31707]]

all situations (Glick et al. 2011, p. 3). We use our expert judgment 
and appropriate analytical approaches to weigh relevant information, 
including uncertainty, in our consideration of various aspects of 
climate change.
    As is the case with all stressors that we assess, even if we 
conclude that a species is currently affected or is likely to be 
affected in a negative way by one or more climate-related impacts, it 
does not necessarily follow that the species meets the definition of an 
``endangered species'' or a ``threatened species'' under the Act. If a 
species is listed as endangered or threatened, knowledge regarding the 
vulnerability of the species to, and known or anticipated impacts from, 
climate-associated changes in environmental conditions can be used to 
help devise appropriate strategies for its recovery.
    Global climate projections are informative, and, in some cases, the 
only or the best scientific information available for us to use. 
However, projected changes in climate and related impacts can vary 
substantially across and within different regions of the world (e.g., 
IPCC 2007a, pp. 8-12). Therefore, we use ``downscaled'' projections 
when they are available and have been developed through appropriate 
scientific procedures, because such projections provide higher 
resolution information that is more relevant to spatial scales used for 
analyses of a given species (see Glick et al. 2011, pp. 58-61, for a 
discussion of downscaling).
    We reviewed climate records and projections for western North 
America, Wyoming, and Colorado to evaluate potential impacts of climate 
change on the PMJM. As described in more detail below, climate models 
predict a trend of continued warming, with hotter summers, warmer 
winters, decreased snowpack, earlier spring melts, increased 
evaporation, more droughts, and reduced summer flows throughout the 
PMJM's range. These conditions will favor more drought-tolerant 
nonnative plants, dramatically altering species compositions within 
riparian habitats and inducing upstream migrations of plants and 
animals to cooler refugia (Perry et al. 2012, p. 828). Drier conditions 
and weaker spring flows will lower water tables and narrow riparian 
corridors (Perry et al. 2012, p. 830), effectively shrinking the PMJM's 
riparian habitats. As a riparian obligate, the PMJM completes the 
majority of its life cycle within the lush, multi-storied riparian 
vegetation that borders streams or other waterbodies. Riparian trees 
and shrubs, such as cottonwoods and willows, dominate the overstory and 
provide cover, while a diverse, grassy understory with beds of dense 
herbaceous vegetation provides food and shelter. The riparian 
vegetation, and in turn, the entire riparian ecosystem, depends on 
water and other hydrologic processes, which the models predict will 
change or be limited under a warmer, drier climate (Perry et al. 2012, 
p. 826). Additionally, increased human populations, development, and 
demand for water may exacerbate the impacts of climate change on 
riparian habitats. Overall, climate change will decrease the quality 
and quantity of the PMJM's riparian habitats, and as a result, the PMJM 
is especially vulnerable when faced with a changing climate.
    The climatic record for western North America indicates that 
concentrations of GHG emissions and mean annual temperatures have 
increased within the range of the PMJM. Atmospheric levels of carbon 
dioxide (CO2), the product of GHG emissions, have increased 
from 280 parts per million (ppm) to 390 ppm by volume since 1750, with 
CO2 concentrations predicted to potentially reach 850 ppm by 
2100 (IPCC 2007, p. 37; Perry et al. 2012, p. 824). Mean annual 
temperatures in western North America increased by 0.5 to 2 degrees C 
(32.9 to 35.6 degrees F) between 1948 and 2002 Perry et al. 2012, p. 
824). Winter and spring temperatures increased significantly and spring 
warming occurred earlier, while autumn temperatures remained relatively 
stable during this time (Perry et al. 2012, p. 824).
    Climate models predict that temperatures within the range of the 
PMJM will continue to increase over time. Most models predict that 
annual temperatures in western North America will increase by an 
additional 2 to 4 degrees C during the 21st century (Perry et al.2012, 
p. 824). Projections for Wyoming predict that the annual mean 
temperature will increase by 4 degrees by 2050 and 6 degrees by 2080 
(WWA 2010). Wyoming will likely experience more warming during the 
summer, with less warming in the winter (WWA 2010). Colorado summers 
are also expected to warm more than winters (CWCB 2008, p. 1). Between 
1997 and 2006, Colorado's mean annual temperature increased by 
approximately 2 degrees (WWA 2010). Relative to the 50-year temperature 
baseline, climate models predict that Colorado will warm by 2.5 degrees 
by 2025 and 4 degrees by 2050 (WWA 2010). As a result, summer 
temperatures typical of the eastern Colorado plains will shift westward 
and upslope, with temperature regimes of the Front Range eventually 
mirroring those currently experienced at the Kansas border (CWCB 2008, 
p. 1). In both Wyoming and Colorado, climate models predict an 
approximately 4 degrees increase in mean annual temperatures throughout 
the range of the PMJM by 2050.
    Precipitation predictions for western North America are less clear 
than the temperature predictions, with variation and uncertainty 
largely attributable to weather systems, such as El Nino (Perry et al. 
2012, p. 824). However, most models agree that in the southwest, winter 
and spring precipitation will decline (Perry et al. 2012, p. 825). Over 
the last 50 to 100 years, the climatic record shows that warming has 
reduced total snow cover and snow water equivalents over much of 
western North America, with continued declines in mountain snowpack 
(Perry et al. p. 825). The warming trend throughout the mountains of 
western North America has decreased snowpack, hastened spring runoff, 
and reduced summer flows (IPCC 2007, p. 11). As a result, over the last 
50 to 100 years, warming and changes in precipitation increased the 
frequency and severity of droughts (Perry et al. 2012, p. 825). As 
precipitation decreases and warmer temperatures increase evaporation, 
the models predict that the frequency and magnitude of droughts will 
intensify during the next century (Perry et al. 2012, p. 825). 
Increased evaporation due to warming will likely offset any projected 
increases in precipitation, leading to greater aridity throughout 
western North America (Perry et al. 2012, p. 825).
    Increased warming, evaporation, and drought, coupled with decreased 
precipitation throughout the range of the PMJM, have strong 
implications for its riparian habitats. The IPCC summarized that 
changes in climate and land use will inflict additional pressures on 
already stressed riparian ecosystems, impacting wetland plants and 
animals and potentially resulting in the loss of biodiversity (IPCC 
2007, p. 234). Riparian ecosystems depend on water and hydrologic 
processes, such as base streamflows, the magnitude and timing of 
floods, and water management and use, factors that are sensitive to 
climate change (Perry et al. 2012, p. 822). As a result, scientists 
expect that climate change will greatly alter riparian hydrology across 
the world (Perry et al. 2012, p. 822).
    Specifically, climate change will likely impact the physiology and 
geographic distribution of the riparian vegetation that define PMJM 
habitats. Although increased levels of atmospheric CO2 may 
physiologically benefit riparian vegetation, such as

[[Page 31708]]

cottonwoods or willows, by improving water use and uptake, limited 
water availability by warming-induced drought, hydrologic changes, and 
increased evaporation will likely supersede any gains (Perry et al. 
2012, p. 826). Additionally, maximum summer temperatures above 45 
degrees C may damage or kill leaf tissues of most riparian plant 
species, increasing heat stress and stunting growth in riparian plants 
(Perry et al. 2012, p. 827). Lower maximum temperatures between 25 
degrees C and 45 degrees C can reduce germination, growth, flowering, 
fruit ripening, and seed set (Perry et al. 2012, p. 827). Relatively 
drought-intolerant species, such as cottonwoods and willows, may be 
particularly vulnerable to less water, promoting colonization by more 
drought-tolerant, nonnative species, such as tamarisk and Russian olive 
(Perry et al. 2012, pp. 826-827). Monocultures of these drought-
tolerant, nonnative species may adversely affect the PMJM (Garber 1995, 
p. 16; Pague and Grunau 2000, p. 1-18). As water levels drop and 
vegetative communities change in favor of drought-tolerant, nonnative 
plants, warming will shift plant species upstream toward higher 
elevations, potentially displacing other plants at these upper limits 
(Perry et al. 2012, p. 828). Therefore, by physiologically impacting 
riparian plants and dramatically altering species compositions toward 
unfavorable, nonnative plant communities, global climate change will 
likely diminish the quality of PMJM habitats throughout the subspecies' 
range.
    Furthermore, earlier and weaker spring floods associated with a 
warming climate may constrict available PMJM riparian habitats. Earlier 
spring floods may decrease the recruitment and establishment of 
riparian tree species by desynchronizing spring runoff with the release 
of seeds (Perry et al. 2012, p. 829). Although earlier and weaker 
spring floods may stabilize streams, eventual channelization and 
narrowing of the flood plains will favor more drought-tolerant plants 
(Perry et al. 2012, p. 829). Where reduced spring flows channelize or 
lower the water table, plant roots will deepen and soil moistures will 
decrease, effectively narrowing the riparian corridor (Perry et al. 
2012, p. 830). Within these narrowed riparian corridors, canopy heights 
and cover will decrease as species shift from drought-intolerant 
cottonwoods, willows, and perennial herbs to more drought-tolerant, 
nonnative species, such as tamarisk or Russian olive (Perry et al. 
2012, p. 830). Communities dominated by nonnative plants with short 
canopies that provide less cover and an open understory do not provide 
suitable PMJM habitat (Garber 1995, p. 16; Pague and Grunau 2000, p. 1-
18; Clippinger 2002, pp. 69, 72; Trainor et al. 2007, pp. 472-476). 
Some waterways may dry seasonally, drastically transitioning from 
perennial to intermittent flows, radically altering species composition 
such that obligate wetland species may disappear (Perry et al. 2012, p. 
830). Therefore, as a warming climate reduces spring flows, constricts 
riparian corridors, and favors nonnative plants over willows, 
cottonwoods, and lush, herbaceous understories, PMJM and its habitats 
may similarly disappear.
    Stark alterations to riparian plant communities stemming from 
climatic warming may reduce the quality and quantity of PMJM habitat 
throughout its range. As habitats diminish and disappear, it follows 
that the diversity and abundance of animal species that rely on these 
habitats will also decrease (Perry et al. 2012, p. 836). As with 
plants, compositions of animals under a warming climate will shift to 
species that are more drought-tolerant and adapted to drier conditions. 
Additionally, warmer maximum temperatures will increase animal 
mortality from heat stress and dehydration (Perry et al. 2012, p. 831-
832). As a riparian obligate, the PMJM will likely be maladapted to the 
drier and hotter habitats expected by 2050.
    Like plants, animal species may escape rising temperatures and 
diminishing habitats by expanding northward, to higher elevations, or 
by retreating upstream (Perry et al. 2012, p. 832). As the climate 
dries and riparian habitats disappear from the eastern boundary of the 
PMJM's range, mice may move upstream toward the west, seeking refuge in 
higher elevation habitats. However, maximum travel distances for PMJM 
as recorded by trapping do not exceed 4.3 km (2.7 mi) (Schorr 2012a, p. 
1274). This travel distance may limit the PMJM's dispersal 
capabilities, especially where riparian habitats are already fragmented 
and isolated by expansive tracts of dry, inhospitable prairies, 
mountains, or human development. In Colorado, a western migration of 
the PMJM may be further limited by the steep, inhospitable, 
decomposing-granite terrain of the Front Range foothills that may 
geographically isolate montane PMJM populations from the prairie 
populations to the east. In Wyoming, the Laramie Range may similarly 
inhibit a western retreat as the climate dries and riparian habitats 
slowly disappear. Additionally, these upstream, smaller-order streams 
and tributaries may be too small to support or develop extensive 
riparian habitats and hence will be unable to sustain larger 
populations of the PMJM. Therefore, a warming climate may further 
confine the PMJM to shrinking habitats within its already narrow range, 
with little possibility of mice seeking refuge within remaining 
upstream habitats.
    The degree of human development, the natural variability in stream 
flow, the ratio of precipitation lost to evaporation, and rates of 
groundwater depletions in the three major river basins that support the 
PMJM may augment the effects of climate change throughout its range 
(Hurd et al. 1999, p. 1404). In other words, impacts associated with 
human development, including groundwater depletions, may exacerbate 
predicted impacts of climate change on the PMJM. Therefore, we conclude 
that the effects of climate change are a threat to the PMJM.
    Summary of Factor E: While uncertainties remain regarding the 
impacts of other natural or manmade factors on the PMJM and its 
habitats, the best available scientific and commercial information 
indicate that these factors are a threat to the long-term conservation 
of the PMJM. Specifically, wildfires and droughts continue to impact 
the PMJM by reducing the quality and quantity of its riparian habitats. 
Intensities and frequencies of these events are predicted to increase 
over time, coupled with increases in floods and nonnative species, 
especially under a warming climate resulting from global climate 
change. Additionally, to the extent that meaningful impacts are 
possible, small and fragmented mouse populations are likely to be more 
vulnerable to these threats.

Cumulative Effects From Factors A Through E

    Many of the threats described in this finding may cumulatively or 
synergistically impact the PMJM beyond the scope of each individual 
threat. For example, residential and commercial development may reduce 
and fragment PMJM habitats. However, development also increases the 
frequency and intensity of floods and wildfires, promotes the 
establishment of nonnative plants, and increases predation. 
Additionally, water use and management by humans strongly reduces flows 
and influences the effects and properties of wildfire, which are likely 
to be frequent and intense during periods of drought (Gresswell 1999; 
Dwire and Kaufman 2003, p. 71). Consequently, increased frequencies

[[Page 31709]]

and intensities of wildfires within riparian habitats or adjacent 
uplands encourage more intense, destructive floods. Furthermore, human 
population growth and demand for more water may intensify the drying 
effects of droughts by promoting the establishment of drought-tolerant, 
nonnative plants, which are in turn more susceptible to wildfire. In 
addition, livestock grazing alone may have little effect on the PMJM or 
its habitats, but when coupled with invading nonnative plants and 
increasing drought, improper grazing may degrade and fragment PMJM 
habitats across larger landscapes.
    Finally, climate change may ultimately augment many of these 
threats acting on the PMJM and its habitats. Within the three river 
basins that support the the PMJM, climate change may exacerbate the 
effects of human development, stream flows, the ratio of precipitation 
lost to evaporation, and rates of groundwater depletions (Hurd et al. 
1999, p. 1404). The warming climate could intensify conflicts between 
human need for water and the sustainability of wetlands and riparian 
areas that are critical to the PMJM. Similarly, hotter summer 
temperatures resulting from climate change may increase the frequency 
and intensity of wildfires, while expanding the influence of drought 
across larger landscapes (IPCC 2007, p. 13). Stream-flow reductions or 
seasonal changes in flow due to climate change and increased human 
demand will probably cause a greater disruption in those watersheds 
with a high level of human development (Hurd et al. 1999, p. 1402). 
Therefore, multiple threats, whether stemming from human development, 
improper grazing, wildfire, floods, or climate change, are likely 
acting cumulatively to further increase the likelihood that the PMJM 
will become endangered within the foreseeable future.

Finding

    As required by the Act, we considered the five factors in assessing 
whether the PMJM is endangered or threatened throughout all of its 
range. We examined the best scientific and commercial information 
available regarding the past, present, and future threats faced by the 
PMJM. We reviewed the two petitions, information available in our 
files, and other available published and unpublished information, and 
we consulted with recognized PMJM experts and other Federal, State, and 
local agencies. New information revealed that the PMJM occupies a 
smaller range in Wyoming than previously thought, and is likely limited 
to areas east of the crest of the Laramie Mountains (Bowe and Beauvais 
2012, p. 8). Additionally, PMJM populations at the Air Force Academy in 
El Paso County, Colorado, declined over 7 years, despite conservation 
efforts, underscoring the importance of reducing upstream impacts and 
maintaining habitat connectivity (Schorr 2012a, p. 1277).
    Our review determined that the alteration, degradation, loss, and 
fragmentation of habitat resulting from urban development, flood 
control, water development, aggregate mining, and other human land uses 
have adversely affected PMJM populations. These threats are ongoing and 
will increase in magnitude as human populations in Colorado and Wyoming 
continue to expand. Additional threats to the PMJM include wildfire, 
drought, small population sizes, and modifications to habitat resulting 
from climate change. We determined that floods, agriculture, grazing, 
and nonnative plants are not currently threats to the PMJM, but may 
increase in magnitude over time as human populations expand and climate 
change increases the frequency and intensity of wildfires and droughts. 
Many of these threats act cumulatively to further degrade habitats and 
negatively impact PMJM populations. Furthermore, we concluded that in 
the absence of the Act, the existing regulatory mechanisms are not 
currently adequate to mitigate the effects of identified threats to 
PMJM.
    Based on our review of the best available scientific and commercial 
information pertaining to the five factors, we find that the threats 
have not been removed nor their imminence, intensity, or magnitude 
sufficiently reduced, and that the species is likely to become 
endangered within the foreseeable future throughout all of its range. 
Therefore, we find that delisting the PMJM is not warranted at this 
time.

Significant Portion of Its Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is endangered or threatened throughout all or a 
significant portion of its range. The Act defines ``endangered 
species'' as any species which is ``in danger of extinction throughout 
all or a significant portion of its range,'' and ``threatened species'' 
as any species which is ``likely to become an endangered species within 
the foreseeable future throughout all or a significant portion of its 
range.'' The definition of ``species'' is also relevant to this 
discussion. The Act defines ``species'' as follows: ``The term 
`species' includes any subspecies of fish or wildlife or plants, and 
any distinct population segment [DPS] of any species of vertebrate fish 
or wildlife which interbreeds when mature.'' The phrase ``significant 
portion of its range'' (SPR) is not defined by the statute, and we have 
never addressed in our regulations: (1) The consequences of a 
determination that a species is either endangered or likely to become 
so throughout a significant portion of its range, but not throughout 
all of its range; or (2) what qualifies a portion of a range as 
``significant.''
    Two recent district court decisions have addressed whether the SPR 
language allows the Service to list or protect less than all members of 
a defined ``species'': Defenders of Wildlife v. Salazar, 729 F. Supp. 
2d 1207 (D. Mont. 2010), vacated as moot, 2012 U.S. App. Lexis 26769 
(9th Circ. Nov. 7, 2012), concerning the Service's delisting of the 
Northern Rocky Mountain gray wolf (74 FR 15123, April 2, 2009); and 
WildEarth Guardians v. Salazar, 2010 U.S. Dist. LEXIS 105253 (D. Ariz. 
September 30, 2010), concerning the Service's 2008 finding on a 
petition to list the Gunnison's prairie dog (73 FR 6660, February 5, 
2008). The Service had asserted in both of these determinations that it 
had authority, in effect, to protect only some members of a 
``species,'' as defined by the Act (i.e., species, subspecies, or DPS), 
under the Act. Both courts ruled that the determinations were arbitrary 
and capricious on the grounds that this approach violated the plain and 
unambiguous language of the Act. The courts concluded that reading the 
SPR language to allow protecting only a portion of a species' range is 
inconsistent with the Act's definition of ``species.'' The courts 
concluded that once a determination is made that a species (i.e., 
species, subspecies, or DPS) meets the definition of ``endangered 
species'' or ``threatened species,'' it must be placed on the list in 
its entirety and the Act's protections applied consistently to all 
members of that species (subject to modification of protections through 
special rules under sections 4(d) and 10(j) of the Act).
    In our July 10, 2008, final rule (73 FR 39790) we stated that the 
SPR language allowed us to list less than all members of a defined 
``species'' and we amended the listing for PMJM to specify that the 
subspecies was threatened in only the Colorado portion of its range, 
effectively delisting the subspecies in Wyoming. We determined that the 
PMJM was not likely to become endangered in the foreseeable future 
throughout all of its range. We based this conclusion primarily on a 
lack of present or

[[Page 31710]]

threatened impacts to the PMJM or its habitat in Wyoming. We found that 
PMJM populations and corresponding threats were concentrated in 
Colorado such that the Colorado portion of the PMJM range warranted 
further consideration as a SPR. Through our analysis, we determined 
that the Colorado portion of the range constituted a SPR and that the 
PMJM was threatened in this SPR. Consistent with our interpretation of 
the SPR phrase at that time, we amended the listing for PMJM to specify 
that the subspecies was threatened in only the Colorado portion of its 
range, effectively delisting PMJM in the Wyoming portion of its range.
    Consistent with the district court decisions discussed above, and 
for the purposes of this finding, we now interpret the phrase 
``significant portion of its range'' in the Act's definitions of 
``endangered species'' and ``threatened species'' to provide an 
independent basis for listing; thus there are two situations (or 
factual bases) under which a species would qualify for listing: A 
species may be endangered or threatened throughout all of its range; or 
a species may be endangered or threatened in only a significant portion 
of its range. If a species is in danger of extinction throughout a 
significant portion of its range, the species is an ``endangered 
species.'' The same analysis applies to ``threatened species.'' Based 
on this interpretation and supported by existing case law, the 
consequence of finding that a species is endangered or threatened in 
only a significant portion of its range is that the entire species 
shall be listed as endangered or threatened, respectively, and the 
Act's protections shall be applied across the species' entire range.
    We conclude, for the purpose of this finding, that interpreting the 
significant portion of its range phrase as providing an independent 
basis for listing is the best interpretation of the Act because it is 
consistent with the purposes and the plain meaning of the key 
definitions of the Act; it does not conflict with established past 
agency practice (i.e., prior to the 2007 Solicitor's Opinion), as no 
consistent, long-term agency practice has been established; and it is 
consistent with the judicial opinions that have most closely examined 
this issue. This interpretation of the significant portion of its range 
phrase does not allow us to reach a similar conclusion for the PMJM in 
Colorado as we did in our 2008 final rule. Instead, as discussed below, 
if we find a species to be endangered or threatened in a significant 
portion of its range, the entire species would be listed as endangered 
or threatened. Having concluded that the phrase ``significant portion 
of its range'' provides an independent basis for listing and protecting 
the entire species, we next turn to the meaning of ``significant'' to 
determine the threshold for when such an independent basis for listing 
exists.
    Although there are potentially many ways to determine whether a 
portion of a species' range is ``significant,'' we conclude for the 
purposes of this finding that the significance of the portion of the 
range should be determined based on its biological contribution to the 
conservation of the species. For this reason, we describe the threshold 
for ``significant'' in terms of an increase in the risk of extinction 
for the species. We conclude that a biologically based definition of 
``significant'' best conforms to the purposes of the Act, is consistent 
with judicial interpretations, and best ensures species' conservation. 
Thus, for the purposes of this finding, and as explained further below, 
a portion of the range of a species is ``significant'' if its 
contribution to the viability of the species is so important that 
without that portion, the species would be in danger of extinction.
    We evaluate biological significance based on the principles of 
conservation biology using the concepts of redundancy, resiliency, and 
representation. Resiliency describes the characteristics of a species 
and its habitat that allow it to recover from periodic disturbance. 
Redundancy (having multiple populations distributed across the 
landscape) may be needed to provide a margin of safety for the species 
to withstand catastrophic events. Representation (the range of 
variation found in a species) ensures that the species' adaptive 
capabilities are conserved. Redundancy, resiliency, and representation 
are not independent of each other, and some characteristic of a species 
or area may contribute to all three. For example, distribution across a 
wide variety of habitat types is an indicator of representation, but it 
may also indicate a broad geographic distribution contributing to 
redundancy (decreasing the chance that any one event affects the entire 
species), and the likelihood that some habitat types are less 
susceptible to certain threats, contributing to resiliency (the ability 
of the species to recover from disturbance). None of these concepts is 
intended to be mutually exclusive, and a portion of a species' range 
may be determined to be ``significant'' due to its contributions under 
any one or more of these concepts.
    For the purposes of this finding, we determine if a portion's 
biological contribution is so important that the portion qualifies as 
``significant'' by asking whether without that portion, the 
representation, redundancy, or resiliency of the species would be so 
impaired that the species would have an increased vulnerability to 
threats to the point that the overall species would be in danger of 
extinction (i.e., would be ``endangered''). Conversely, we would not 
consider the portion of the range at issue to be ``significant'' if 
there is sufficient resiliency, redundancy, and representation 
elsewhere in the species' range that the species would not be in danger 
of extinction throughout its range if the population in that portion of 
the range in question became extirpated.
    We recognize that this definition of ``significant'' (a portion of 
the range of a species is ``significant'' if its contribution to the 
viability of the species is so important that without that portion, the 
species would be in danger of extinction) establishes a threshold that 
is relatively high. On the one hand, given that the consequences of 
finding a species to be endangered or threatened in a significant 
portion of its range would be listing the species throughout its entire 
range, it is important to use a threshold for ``significant'' that is 
robust. It would not be meaningful or appropriate to establish a very 
low threshold whereby a portion of the range can be considered 
``significant'' even if only a negligible increase in extinction risk 
would result from its loss. Because nearly any portion of a species' 
range can be said to contribute some increment to a species' viability, 
use of such a low threshold would require us to impose restrictions and 
expend conservation resources disproportionately to conservation 
benefit: Listing would be rangewide, even if only a portion of the 
range of minor conservation importance to the species is imperiled. On 
the other hand, it would be inappropriate to establish a threshold for 
``significant'' that is too high. This would be the case if the 
standard were, for example, that a portion of the range can be 
considered ``significant'' only if threats in that portion result in 
the entire species' being currently endangered or threatened. Such a 
high bar would not give the significant portion of its range phrase 
independent meaning, as the Ninth Circuit held in Defenders of Wildlife 
v. Norton, 258 F.3d 1136 (9th Cir. 2001).
    The definition of ``significant'' used in this finding carefully 
balances these concerns. By setting a relatively high threshold, we 
minimize the degree to which restrictions will be imposed or

[[Page 31711]]

resources expended that do not contribute substantially to species 
conservation. But, we have not set the threshold so high that the 
phrase ``in a significant portion of its range'' loses independent 
meaning. Specifically, we have not set the threshold as high as it was 
under the interpretation presented by the Service in the Defenders of 
Wildlife v. Norton, 258 F.3d 1136 (9th Cir. 2001), litigation. Under 
that interpretation, the portion of the range would have to be so 
important that current imperilment there would mean that the species 
would be currently imperiled everywhere. Under the definition of 
``significant'' used in this finding, the portion of the range need not 
rise to such an exceptionally high level of biological significance. 
(We recognize that if the species is imperiled in a portion that rises 
to that level of biological significance, then we should conclude that 
the species is in fact imperiled throughout all of its range, and that 
we would not need to rely on the significant portion of its range 
language for such a listing.) Rather, under this interpretation we ask 
whether the species would be endangered everywhere without that 
portion, i.e., if that portion were completely extirpated. In other 
words, the portion of the range need not be so important that even the 
species being in danger of extinction in that portion would be 
sufficient to cause the species in the remainder of the range to be 
endangered; rather, the complete extirpation (in a hypothetical future) 
of the species in that portion would be required to cause the species 
in the remainder of the range to be endangered.
    The range of a species can theoretically be divided into portions 
in an infinite number of ways. However, there is no purpose to 
analyzing portions of the range that have no reasonable potential to be 
significant or to analyzing portions of the range in which there is no 
reasonable potential for the species to be endangered or threatened. To 
identify only those portions that warrant further consideration, we 
determine whether there is substantial information indicating that: (1) 
The portions may be ``significant,'' and (2) the species may be in 
danger of extinction there or likely to become so within the 
foreseeable future. Depending on the biology of the species, its range, 
and the threats it faces, it might be more efficient for us to address 
the significance question first or the status question first. Thus, if 
we determine that a portion of the range is not ``significant,'' we do 
not need to determine whether the species is endangered or threatened 
there; if we determine that the species is not endangered or threatened 
in a portion of its range, we do not need to determine if that portion 
is ``significant.'' In practice, a key part of the determination that a 
species is in danger of extinction in a significant portion of its 
range is whether the threats are geographically concentrated in some 
way. If the threats to the species are essentially uniform throughout 
its range, no portion is likely to warrant further consideration. 
Moreover, if any concentration of threats to the species occurs only in 
portions of the species' range that clearly would not meet the 
biologically based definition of ``significant,'' such portions will 
not warrant further consideration.
    If a species has been found to meet the definition of ``threatened 
species'' throughout its range, as we have found for PMJM, we must then 
analyze whether there are any significant portions of the range that 
meet the definition of ``endangered species.'' If the subspecies is 
determined to be ``endangered'' within the ``significant'' portion of 
the range, then the entire subspecies should be listed as 
``endangered.'' We consider the ``range'' of the PMJM to include 
portions of four counties (Albany, Laramie, Platte, and Converse) in 
Wyoming and portions of seven counties (Boulder, Douglas, El Paso, 
Elbert, Jefferson, Larimer, and Weld) in Colorado.
    To determine whether the PMJM could be considered an endangered 
species in a ``significant portion of its range,'' we reviewed the best 
available scientific information with respect to the geographic 
concentration of threats and the significance of portions of the range 
to the conservation of the species. We evaluated whether substantial 
information indicated (i) The threats are so concentrated in any 
portion of the species' range that the species may be currently in 
danger of extinction in that portion; and (ii) whether those portions 
may be significant to the conservation of the species. Our rangewide 
review of the species concluded that the PMJM is a threatened species 
throughout its range. As described above, to establish whether any 
areas may warrant further consideration, we reviewed our analysis of 
the five listing factors to determine whether any of the potential 
threats identified were so concentrated that some portion of the PMJM's 
range may be in danger of extinction now or in the foreseeable future.
    We found that threats occur throughout the PMJM's range, in both 
Colorado and Wyoming, but are more concentrated in Colorado. These 
threats include, but are not limited to: Wildfire, drought, climate 
change, small populations, and the inadequacy of existing regulations. 
We identified the continued decline in the extent and quality of 
habitat as the primary threat to the PMJM. Activities resulting in this 
decline, include, but are not limited to: Residential and commercial 
development, transportation projects, hydrologic changes, and aggregate 
mining. Additionally, we found that many of these threats act 
cumulatively to further reduce the extent and quality of PMJM habitat 
now and in the future. Although threats occur throughout the PMJM's 
range, human population projections suggest that the magnitude of many 
of these threats will increase over time more in Colorado than Wyoming. 
For instance, Colorado's human population will grow more than 
populations in Wyoming, suggesting that threats associated with 
development, transportation, and hydrologic changes will be greater in 
Colorado than Wyoming. Given this concentration of threats in Colorado, 
we analyzed whether the Colorado portion of the PMJM's range meets the 
definition of ``significant.'' Because the Colorado portion of the 
range comprises the majority of the PMJM population, if this portion 
were to become extirpated, it is likely that the remaining portion in 
Wyoming would be imperiled due to its small size and the continued 
presence of threats. In other words, the representation, redundancy, or 
resiliency of the remaining, smaller PMJM populations in Wyoming 
following the extirpation of the PMJM in Colorado would be so impaired 
that the subspecies would have an increased vulnerability to threats to 
the point that the overall species would be in danger of extinction 
(i.e., would be ``endangered''). Therefore, the Colorado portion of the 
range meets the definition of ``significant.''
    After determining that Colorado represents a significant portion of 
the PMJM's range, we analyzed whether threats rise to a level such that 
the subspecies is currently in danger of extinction, or ``endangered,'' 
in Colorado. We determined that they do not, because none of those 
threats, either independently or collectively, reduced, destroyed, or 
fragmented habitats such that the PMJM is currently in danger of 
extinction in Colorado. While these threats continue and may have 
increased since our original listing, we have no information to 
indicate that populations declined or the threats increased such that 
the PMJM is

[[Page 31712]]

currently in danger of becoming extinct in Colorado. Although capture 
rates are low and populations have declined, trapping surveys continue 
to capture the PMJM in habitats previously identified as occupied. 
Therefore, the available information suggests that the PMJM is not 
currently in danger of becoming extinct in Colorado, but remains 
threatened throughout its range as described above in Factors A through 
E.
    Our review of the best available scientific and commercial 
information indicates that the PMJM is likely to become endangered 
within the foreseeable future throughout all of its range. Therefore, 
we find that delisting the PMJM under the Act is not warranted at this 
time. We request that you submit any new information concerning the 
status of, or threats to, the PMJM to our Colorado Fish and Wildlife 
Office (see ADDRESSES section) whenever it becomes available. New 
information will help us monitor the status of the PMJM and contribute 
to its conservation and recovery.

References Cited

    A complete list of references cited is available on the Internet at 
http://www.regulations.gov at Docket No. FWS-R6-ES-2012-0095 and upon 
request from the Colorado Field Office (see ADDRESSES).

Authors

    The primary authors of this document are staff located at the 
Colorado Field Office (see ADDRESSES).

    Dated: May 13, 2013.
Stephen Guertin,
Deputy Director, Fish and Wildlife Service
[FR Doc. 2013-12387 Filed 5-23-13; 8:45 am]
BILLING CODE 4310-55-P