[Federal Register Volume 78, Number 132 (Wednesday, July 10, 2013)]
[Proposed Rules]
[Pages 41550-41608]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-16520]



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Vol. 78

Wednesday,

No. 132

July 10, 2013

Part III





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





 Endangered and Threatened Wildlife and Plants; Designation of Critical 
Habitat for the Northern Mexican Gartersnake and Narrow-Headed 
Gartersnake; Proposed Rule

  Federal Register / Vol. 78 , No. 132 / Wednesday, July 10, 2013 / 
Proposed Rules  

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2013-0022; 4500030113]
RIN 1018-AZ35


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for the Northern Mexican Gartersnake and Narrow-Headed 
Gartersnake

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service, propose to designate 
critical habitat for the northern Mexican gartersnake (Thamnophis eques 
megalops) and narrow-headed gartersnake (Thamnophis rufipunctatus) in 
Arizona and New Mexico, under the Endangered Species Act of 1973, as 
amended (Act). If we finalize this rule as proposed, it would extend 
the Act's protections to these species' habitats. The effect of this 
regulation is to conserve northern Mexican and narrow-headed 
gartersnake habitat under the Act.

DATES: We will accept comments received or postmarked on or before 
September 9, 2013. Comments submitted electronically using the Federal 
eRulemaking Portal (see ADDRESSES section, below) must be received by 
11:59 p.m. Eastern Time on the closing date. We must receive requests 
for public hearings, in writing, at the address shown in the FOR 
FURTHER INFORMATION CONTACT section by August 26, 2013.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. Search for Docket No. FWS-R2-ES-2013-0022, which 
is the docket number for this rulemaking. You may submit a comment by 
clicking on ``Comment Now!''
    (2) By hard copy: Submit by U.S. mail or hand-delivery to: Public 
Comments Processing, Attn: FWS-R2-ES-2013-0022; Division of Policy and 
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax 
Drive, MS 2042-PDM; Arlington, VA 22203.
    We request that you send comments only by the methods described 
above. We will post all comments on http://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see the Information Requested section below for more information).
    The coordinates or plot points or both from which the critical 
habitat maps are generated are included in the administrative record 
for this rulemaking and are available at http://www.fws.gov/southwest/es/arizona, http://www.regulations.gov at Docket No. FWS-R2-ES-2013-
0022, and at the Arizona Ecological Services Field Office (see FOR 
FURTHER INFORMATION CONTACT). Any additional tools or supporting 
information that we may develop for this rulemaking will also be 
available at the Fish and Wildlife Service Web site and Field Office 
set out above, and may also be included in the preamble of this 
proposal and/or at http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, U.S. 
Fish and Wildlife Service, Arizona Ecological Services Field Office, 
2321 West Royal Palm Road, Suite 103, Phoenix, AZ 85021; telephone: 
602-242-0210; facsimile: 602-242-2513. If you use a telecommunications 
device for the deaf (TDD), call the Federal Information Relay Service 
(FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Act, once a species is 
determined to be an endangered or threatened species throughout all or 
a significant portion of its range, we are required to promptly publish 
a proposal in the Federal Register and make a determination on our 
proposal within 1 year. Additionally, critical habitat shall be 
designated, to the maximum extent prudent and determinable, for any 
species determined to be an endangered or threatened species under the 
Act. Designations and revisions of critical habitat can only be 
completed by issuing a rule. Elsewhere in today's Federal Register, we 
propose to list the northern Mexican and narrow-headed gartersnakes as 
threatened species under the Act.
    This rule consists of: A proposed rule for designation of critical 
habitat for northern Mexican and narrow-headed gartersnakes. These 
gartersnakes are proposed for listing under the Act. This rule proposes 
designation of critical habitat necessary for the conservation of the 
species.
    The basis for our action. Under the Act, when a species is proposed 
for listing, to the maximum extent prudent and determinable, we must 
designate critical habitat for the species. These species are proposed 
for listing as threatened. Therefore, we propose to designate critical 
habitat for the northern Mexican gartersnake in Greenlee, Graham, 
Apache, La Paz, Mohave, Yavapai, Navajo, Gila, Coconino, Cochise, Santa 
Cruz, Pima, and Pinal Counties in Arizona, as well as in Grant and 
Catron Counties in New Mexico, and critical habitat for the narrow-
headed gartersnake in Greenlee, Graham, Apache, Yavapai, Navajo, Gila, 
and Coconino Counties in Arizona, as well as in Grant, Hidalgo, Sierra, 
and Catron Counties in New Mexico.
    We will seek peer review. We are seeking comments from 
knowledgeable individuals with scientific expertise to review our 
analysis of the best available science and application of that science 
and to provide any additional scientific information to improve this 
proposed rule. Because we will consider all comments and information 
received during the comment period, our final determinations may differ 
from this proposal.

Information Requested

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other concerned governmental agencies, 
Native American tribes, the scientific community, industry, or any 
other interested parties concerning this proposed rule. We particularly 
seek comments concerning:
    (1) The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act (16 U.S.C. 1531 et 
seq.), including whether there are threats to the species from human 
activity, the degree of which can be expected to increase due to the 
designation, and whether that increase in threats outweighs the benefit 
of designation such that the designation of critical habitat is not 
prudent.
    (2) Specific information on:
    (a) The amount and distribution of northern Mexican or narrow-
headed gartersnakes and their habitat;
    (b) What may constitute ``physical or biological features essential 
to the conservation of the species,'' within the geographical range 
currently occupied by the species;
    (c) Where these features are currently found;
    (d) Whether any of these features may require special management 
considerations or protection;
    (e) What areas, that were occupied at the time of listing (or are 
currently occupied) and that contain features

[[Page 41551]]

essential to the conservation of the species, should be included in the 
designation and why; and
    (f) What areas not occupied at the time of listing are essential 
for the conservation of the species and why.
    (3) Land use designations and current or planned activities in the 
areas occupied by the species or proposed to be designated as critical 
habitat, and possible impacts of these activities on this species and 
proposed critical habitat.
    (4) Any foreseeable economic, national security, or other relevant 
impacts that may result from designating any area that may be included 
in the final designation. We are particularly interested in any impacts 
on small entities, and the benefits of including or excluding areas 
from the proposed designation that are subject to these impacts.
    (5) Whether our approach to designating critical habitat could be 
improved or modified in any way to provide for greater public 
participation and understanding, or to assist us in accommodating 
public concerns and comments.
    (6) The likelihood of adverse social reactions to the designation 
of critical habitat and how the consequences of such reactions, if 
likely to occur, would relate to the conservation and regulatory 
benefits of the proposed critical habitat designation.
    (7) If considered for exclusion from critical habitat designation 
under section 4(b)(2) of the Act, documentation that describes how 
lands are managed for wildlife and habitat and how that management 
specifically benefits either or both the northern Mexican or narrow-
headed gartersnake or their prey bases.
    Please include sufficient information with your submission (such as 
scientific journal articles or other publications) to allow us to 
verify any scientific or commercial information you include.
    Please note that submissions merely stating support for or 
opposition to the action under consideration without providing 
supporting information, although noted, will not be considered in 
making a determination, as section 4(b)(1)(A) of the Act directs that 
determinations as to whether any species is an endangered or threatened 
species must be made ``solely on the basis of the best scientific and 
commercial data available.''
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We request 
that you send comments only by the methods described in the ADDRESSES 
section.
    If you submit information via http://www.regulations.gov, your 
entire submission--including any personal identifying information--will 
be posted on the Web site. If your submission is made via a hardcopy 
that includes personal identifying information, you may request at the 
top of your document that we withhold this information from public 
review. However, we cannot guarantee that we will be able to do so. We 
will post all hardcopy submissions on http://www.regulations.gov.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on http://www.regulations.gov, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Arizona Ecological Services Field Office (see FOR 
FURTHER INFORMATION CONTACT).

Previous Federal Actions

    All previous Federal actions are described in the proposal to list 
the northern Mexican and narrow-headed gartersnakes as threatened 
species under the Act published elsewhere in today's Federal Register.

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species and
    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot be otherwise 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that Federal agencies ensure, in consultation 
with the Service, that any action they authorize, fund, or carry out is 
not likely to result in the destruction or adverse modification of 
critical habitat. The designation of critical habitat does not affect 
land ownership or establish a refuge, wilderness, reserve, preserve, or 
other conservation area. Such designation does not allow the government 
or public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by 
non-Federal landowners. Where a landowner requests Federal agency 
funding or authorization for an action that may affect a listed species 
or critical habitat, the consultation requirements of section 7(a)(2) 
of the Act would apply, but even in the event of a destruction or 
adverse modification finding, the obligation of the Federal action 
agency and the landowner is not to restore or recover the species, but 
to implement reasonable and prudent alternatives to avoid destruction 
or adverse modification of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographic area occupied by the species at the time it 
was listed are included in a critical habitat designation if they 
contain physical or biological features (1) which are essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For these areas, critical 
habitat designations identify, to the extent known using the best 
scientific and commercial data available, those physical or biological 
features that are essential to the conservation of the species (such as 
space, food, cover, and protected habitat). In identifying those 
physical and biological features within an area, we focus on the 
principal biological or physical constituent elements (primary 
constituent elements such as roost sites, nesting grounds, seasonal 
wetlands, water quality, tide, soil type, etc.) that are essential to 
the conservation of the species. Primary constituent elements are the 
elements of physical or biological features that, when laid out in the 
appropriate quantity and spatial arrangement to provide for a species' 
life-history processes, are essential to the conservation of the 
species.
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographic area 
occupied by

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the species at the time it is listed, upon a determination that such 
areas are essential for the conservation of the species. For example, 
an area currently occupied by the species, but that was not occupied at 
the time of listing, may be essential to the conservation of the 
species and may be included in the critical habitat designation. We 
designate critical habitat in areas outside the geographic area 
occupied by a species only when a designation limited to its range 
would be inadequate to ensure the conservation of the species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Further, our Policy on 
Information Standards Under the Endangered Species Act (published in 
the Federal Register on July 1, 1994 (59 FR 34271)), the Information 
Quality Act (section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), 
and our associated Information Quality Guidelines, provide criteria, 
establish procedures, and provide guidance to ensure that our decisions 
are based on the best scientific data available. They require our 
biologists, to the extent consistent with the Act and with the use of 
the best scientific data available, to use primary and original sources 
of information as the basis for recommendations to designate critical 
habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources may include the recovery plan for the 
species, articles in peer-reviewed journals, conservation plans 
developed by States and counties, scientific status surveys and 
studies, biological assessments, other unpublished materials, or 
experts' opinions or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. We recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be needed 
for recovery of the species. Areas that are important to the 
conservation of the species, both inside and outside the critical 
habitat designation, will be subject to: (1) Conservation actions 
implemented under section 7(a)(1) of the Act, (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to ensure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species, and (3) the prohibitions of section 9 of the Act if actions 
occurring in these areas may affect the species. Federally funded or 
permitted projects affecting listed species outside their designated 
critical habitat areas may still result in jeopardy findings in some 
cases. These protections and conservation tools will continue to 
contribute to recovery of this species. Similarly, critical habitat 
designations made on the basis of the best available information at the 
time of designation will not control the direction and substance of 
future recovery plans, habitat conservation plans (HCPs), or other 
species conservation planning efforts if new information available at 
the time of these planning efforts calls for a different outcome.

Prudency Determination

    Section 4(a)(3) of the Act, as amended, and implementing 
regulations (50 CFR 424.12), require that, to the maximum extent 
prudent and determinable, the Secretary shall designate critical 
habitat at the time the species is determined to be an endangered or 
threatened species. Our regulations (50 CFR 424.12(a)(1)) state that 
the designation of critical habitat is not prudent when one or both of 
the following situations exist:
    (1) The species is threatened by taking or other human activity, 
and identification of critical habitat can be expected to increase the 
degree of threat to the species, or
    (2) Such designation of critical habitat would not be beneficial to 
the species.
    There is currently no imminent threat of take attributed to 
collection or vandalism for either of these species, and identification 
and mapping of critical habitat is not expected to initiate any such 
threat. In the absence of finding that the designation of critical 
habitat would increase threats to a species, if there are any benefits 
to a critical habitat designation, then a prudent finding is warranted. 
Here, the potential benefits of designation include: (1) Triggering 
consultation under section 7 of the Act, in new areas for actions in 
which there may be a Federal nexus where it would not otherwise occur 
because, for example, it is or has become unoccupied or the occupancy 
is in question; (2) focusing conservation activities on the most 
essential features and areas; (3) providing educational benefits to 
State or county governments or private entities; and (4) preventing 
people from causing inadvertent harm to the species. Therefore, because 
we have determined that the designation of critical habitat would not 
likely increase the degree of threat to the species and may provide 
some measure of benefit, we find that designation of critical habitat 
is prudent for the northern Mexican and narrow-headed gartersnakes.

Critical Habitat Determinability

    Having determined that designation is prudent, under section 
4(a)(3) of the Act, we must find whether critical habitat for the 
northern Mexican and narrow-headed gartersnakes is determinable. Our 
regulations at 50 CFR 424.12(a)(2) state that critical habitat is not 
determinable when one or both of the following situations exist:
    (i) Information sufficient to perform required analyses of the 
impacts of the designation is lacking, or
    (ii) The biological needs of the species are not sufficiently well 
known to permit identification of an area as critical habitat. When 
critical habitat is not determinable, the Act allows the Service an 
additional year to publish a critical habitat designation (16 U.S.C. 
1533(b)(6)(C)(ii)).
    We reviewed the best available scientific and commercial 
information pertaining to the biological needs of the species and 
habitat characteristics where the species are located. Based on this 
information, we conclude that sufficient information is known regarding 
the species' needs and habitats to determine critical habitat for the 
northern Mexican and narrow-headed gartersnakes.

Physical or Biological Features

    In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and 
regulations at 50 CFR 424.12, in determining which areas within the 
geographic area occupied by the species at the time of listing to 
designate as critical habitat, we consider the physical or biological 
features that are essential to the conservation of the species and 
which may require special management considerations or protection. 
These include, but are not limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and

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    (5) Habitats that are protected from disturbance or are 
representative of the historical, geographic, and ecological 
distributions of a species.
    We derived the specific physical or biological features (PBFs) 
required for the northern Mexican and narrow-headed gartersnakes from 
the best available scientific and commercial information available, 
including research of these species' habitat, ecology, and life history 
as described below. Additional insight is provided by Rosen and 
Schwalbe (1988, pp. 14-48), Degenhardt et al. (1996, pp. 317-319, 326-
328), Rossman et al. (1996, pp. 55-116, 171-177, 241-248), and Ernst 
and Ernst (2003, pp. 391-393, 416-419). We have determined that the 
following physical or biological features are essential for northern 
Mexican and narrow-headed gartersnakes:
Space and Physical Habitat Requirements for Individual and Population 
Growth and for Normal Behavior
    Both the northern Mexican and narrow-headed gartersnakes depend on 
the presence of water, primarily for the maintenance of their primary 
aquatic prey bases, not because their own physiology requires an 
aquatic environment. The northern Mexican gartersnake is a riparian 
obligate and occurs chiefly in streams, rivers, cienegas, stock tanks, 
and spring sources that are often found within large-river riparian 
woodlands and forests and streamside gallery forests (defined as well-
developed broadleaf deciduous riparian forests with limited, if any, 
herbaceous ground cover or dense grass) (Hendrickson and Minckley 1984, 
p. 131; Rosen and Schwalbe 1988, pp. 14-16; Arizona Game and Fish 
Department 2001, p. 2). Northern Mexican gartersnakes occur at 
elevations from 130 to 8,497 feet (ft) (40 to 2,590 meters (m)) 
(Rossman et al. 1996, p. 172), and in a wide range of biotic 
communities, including Sonoran Desertscrub at the lower elevations, 
through Semidesert Grassland, Interior Chaparral, and Madrean Evergreen 
Woodland and into the lower reaches of Petran Montane Conifer Forest as 
elevation increases (Brennan and Holycross 2006, p. 122). Narrow-headed 
gartersnakes are widely considered to be one of the most aquatic 
gartersnake species (Rossman et al. 1996, p. 246), and are strongly 
associated with clear, rocky streams, using predominantly pool and 
riffle habitat that includes cobbles and boulders (Rosen and Schwalbe 
1988, pp. 33-34; Degenhardt et al. 1996, p. 327; Rossman et al. 1996, 
p. 246). Narrow-headed gartersnakes occur at elevations from 
approximately 2,300-8,200 ft (700 m-2,500 m), inhabiting Petran Montane 
Conifer Forest, Great Basin Conifer Woodland, Interior Chaparral, and 
the Arizona Upland subdivision of Sonoran Desertscrub communities 
(Rosen and Schwalbe 1988, p. 33; Brennan and Holycross 2006, p. 122; 
Burger 2008).
    Northern Mexican gartersnakes employ a variety of strategies when 
foraging for prey. Rosen and Schwalbe (1988, p. 21) observed: (1) 
Aquatic and terrestrial ambush; (2) aquatic foraging in riffles, 
vegetation mats, and in open water (such as pool habitat, stock tanks, 
etc.); and (3) opportunistic capitalization on transitory 
concentrations of prey. These observations suggest that areas with slow 
riffles, pools, and backwater habitat are important for prey 
acquisition, because the prey of northern Mexican gartersnakes are 
largely aquatic and the snakes themselves need to remain somewhat 
stabilized to allow for striking behaviors. Narrow-headed gartersnakes 
often forage underwater, using concealment and ambush behaviors within 
and between boulder and cobble complexes along the bottom of streams 
(Rosen and Schwalbe 1988; p. 39). Hibbitts and Fitzgerald (2005, p. 
364) described their hunting technique in greater detail, which 
included anchoring their body with their tail around rocks on the 
bottom of streams and orienting themselves in position with the 
current, with their head and neck exposed to the force of the water and 
the body unanchored on the substrate to allow for forward directed 
strikes. Narrow-headed gartersnakes are believed to be mainly visual 
hunters (Hibbitts and Fitzgerald 2005, p. 364) and heavily dependent on 
visual cues when foraging, based on comparative analyses among other 
species of gartersnakes (de Queiroz 2003, p. 381). However, foraging 
activity that occurs during the monsoon season, which is characterized 
by turbid water conditions, suggests they also use chemosensory 
abilities to direct strikes. This information suggests that the 
presence of rock structure along the bottom of streams is important to 
narrow-headed gartersnakes in compensating for the inertia of flow and 
for providing opportunities for camouflage-based ambush. However, 
Fitzgerald (1986; Table 4) also found narrow-headed gartersnakes 
foraging in stream and river reaches characterized as having sandy 
substrates. These observations suggest a more opportunistic nature of 
foraging behavior that may be based more on the presence of prey than 
the type of substrate.
    Both northern Mexican and narrow-headed gartersnakes are largely 
dependent on native fish as a primary source of food, but have been 
observed using nonnative, soft-rayed fish species as prey on occasion; 
for narrow-headed gartersnakes, fish are the principle prey item (Rosen 
and Schwalbe 1988, pp. 18, 38-39; Degenhardt et al. 1996, p. 328; 
Rossman et al. 1996, p. 247; Nowak 2006, p. 22). Therefore, habitat-
based attributes that are important for the survival of fish prey 
species are equally important for the survival of northern Mexican and 
narrow-headed gartersnakes. Many species of native and nonnative soft-
rayed fish require unregulated flows (or flooding) for: (1) Removing 
excess sediment from some portions of the stream; (2) removing 
predatory nonnative, spiny-rayed fish species from a given area; and 
(3) increasing prey species diversity. Flows fluctuate seasonally, with 
snowmelt causing spring pulses and occasional floods, and late-summer 
or monsoonal rains producing floods of varying intensity and duration. 
These high flows likely rejuvenate spawning and foraging habitat for 
native and nonnative, soft-rayed fish (Propst et al. 1986, p. 3), 
break-up embedded bottom materials (Mueller 1984, p. 355), stimulate 
spawning, and enhance recruitment of native species by eliminating or 
reducing populations of harmful nonnative species (Stefferud and Rinne 
1996a, p. 80), such as spiny-rayed fish. Flooding also allows for the 
scouring of sand and gravel in riffle areas, which reduces the degree 
of embeddedness of cobble and boulder substrates (Britt 1982, p. 45). 
Typically, sediment is carried along the bed of a stream and deposited 
at the downstream, undersurface side of cobbles and boulders. Over 
time, this can result in the filling of cavities under cobbles and 
boulders (Rinne 2001, p. 69). Flooding removes the extra sediment, and 
the cavities created under cobbles by the scouring action of the flood 
waters provide enhanced opportunities for spawning of native fish, as 
well as foraging opportunities, particularly for narrow-headed 
gartersnakes.
    In addition to aquatic habitat, northern Mexican and narrow-headed 
gartersnakes rely on terrestrial habitat for thermoregulation, 
gestation, shelter, protection from predators, immigration, emigration, 
and brumation (cold-season dormancy). The northern Mexican gartersnake 
also uses terrestrial habitat for foraging opportunities when primary 
prey items, such as leopard frogs and

[[Page 41554]]

native fish, are uncommon or absent from aquatic habitats. Rosen (1991, 
pp. 308-309) found that northern Mexican gartersnakes spent 
approximately 60 percent of their time moving, 13 percent of their time 
basking on vegetation, 18 percent of their time basking on the ground, 
and 9 percent of their time under surface cover. Foraging may occur 
spontaneously and opportunistically during any of these behaviors. In 
studying the Mexican gartersnake, Drummond and Marc[iacute]as-
Garc[iacute]a (1983, pp. 24, 35) found individuals wandering hundreds 
of meters away from water, perhaps in response to a decline or 
disappearance of the prey base. Observation records for northern 
Mexican gartersnakes from semi-remote livestock tanks and spring 
sources suggest the species moves across the local landscape as part of 
its foraging ecology. Rosen and Schwalbe (1988, p. 47) suggested that 
vegetation such as knotgrass, deergrass, sacaton, cattails, tules, and 
spikerush were important to the northern Mexican gartersnake, as well 
as the presence of rock piles. Boyarski (2011, p. 3) found that four of 
five telemetered northern Mexican gartersnakes over-wintered along a 
hillside ``immediately south'' of hatchery ponds where they spent the 
majority of their time during the surface-active season, but the 
distance of those specific over-wintering sites was not disclosed. 
However, Rosen and Schwalbe (1988, p. 27) report observing northern 
Mexican gartersnakes at a distance of 330 ft (100 m) away from 
permanent water.
    Important terrestrial habitat components for the narrow-headed 
gartersnake include cobbles, boulders, and bankside shrub vegetation 
for basking and foraging (Fleharty 1967, pp. 215-216; Rosen and 
Schwalbe 1988, p. 48; Ernst and Ernst 2003, p. 418). In the Black River 
and Oak Creek in Arizona, the majority of narrow-headed gartersnakes 
captured were observed under rocks or shoreline debris, which may 
indicate these habitat components are ecologically important (Brennan 
and Rosen 2009, pp. 7, 11). In order of preference, Jennings and 
Christman (2011, pp. 14, 20) found that narrow-headed gartersnakes used 
rocks, logs or stumps, and debris jams as cover. Narrow-headed 
gartersnake detections appear to correlate with the presence of large 
willows growing along the streambank, which are used for basking 
(Fernandez and Rosen 1996, p. 70). Holycross et al. (2006, p. 51) found 
that willows overhanging the stream channel are particularly important 
for adult narrow-headed gartersnakes. The greater need of narrow-headed 
gartersnakes to thermoregulate at higher elevations makes optimal 
basking sites, such as shrubs and snags, essential (Rosen and Schwalbe 
1988, p. 34). Pregnant female narrow-headed gartersnakes are rarely 
encountered near streams, apparently moving away from water during 
gestation, in favor of the higher thermal environs of rock piles (Rosen 
and Schwalbe 1988, pp. 33-34, 48). Telemetry data presented in Nowak 
(2006, pp. 17-18) suggest that terrestrial habitat is important to 
narrow-headed gartersnakes; home ranges were often set up perpendicular 
to the stream channel, while others were parallel to the channel. This 
orientation of home ranges likely indicates the species uses both 
active and inactive channels, depending on the activity. Such channels 
are typically found within 600 ft (182.9 m) of active stream channels. 
For example, it is ecologically disadvantageous for an individual 
gartersnake to brumate within the bankfull boundary of an active stream 
because of the risk of flooding, and subsequent drowning, during the 
cold-season dormancy period. This hypothesis is supported by the 
findings of Nowak (2006, pp. 19-21), which found telemetered narrow-
headed gartersnakes using crevices in rock walls or large rock outcrops 
as over-wintering sites, some as far as 650 ft (200 m) away from the 
stream channel. Additionally, micro-sites chosen as cover for 
gartersnakes may be artificial or natural; Nowak (2006, p. 19) reported 
observing narrow-headed gartersnakes commonly using such items such as 
rock foundations and retaining walls, chimneys, and old water pipes 
under house foundations, vegetation thickets, burrows, boulders, and 
downed logs. The largest home range documented by Jennings and 
Christman (2011, p. 18) for narrow-headed gartersnakes was 239,077 
square feet (22,211 square meters), but home range sizes in this study 
were considered to be underestimated by the authors.
    Therefore, based on the information above, we identify the presence 
of aquatic habitats to support individual and population growth, and 
support normal behavior, and the presence of terrestrial habitats in 
appropriate proximity to occupied aquatic habitats to support 
individual and population growth, and support normal behavior, to be 
physical or biological features for these species.
Biotic Community Requirements for Individual and Population Growth
    The success of northern Mexican and narrow-headed gartersnake 
populations appears to be uniquely tied to the presence of adequate 
native prey populations, and, in some cases, nonnative prey species 
consisting of larval and juvenile bullfrogs, as well as soft-rayed, 
nonnative fish species (Rosen and Schwalbe 1988, pp. 18, 20, 44; 
Holycross et al. 2006, p. 23). Generally, the diet of the northern 
Mexican gartersnake consists predominantly of amphibians and fishes, 
but other invertebrates and vertebrate species may also be used 
opportunistically (Gregory et al. 1980, pp. 87, 90-92; Rosen and 
Schwalbe 1988, pp. 18, 20; Holm and Lowe 1995, pp. 30-31; Degenhardt et 
al. 1996, p. 318; Rossman et al. 1996, p. 176; Manjarrez 1998). 
Marc[iacute]as-Garc[iacute]a and Drummond (1988, pp. 129-134) found 
that adult northern Mexican gartersnakes in Hidalgo, Mexico, primarily 
fed on aquatic vertebrates, whereas juveniles often fed on 
invertebrates, such as earthworms and leeches. Narrow-headed 
gartersnakes specialize on fish (primarily native fish and, 
secondarily, nonnative, soft-rayed species, such as trout) as their 
principle prey item (Rosen and Schwalbe 1988, pp. 38-39; Nowak 2006, 
pp. 22-23; Degenhardt et al. 1996, p. 328; Rossman et al. 1996, p. 
247). Detailed information on the diet of northern Mexican and narrow-
headed gartersnakes is presented in the proposed rule to list both 
species as threatened under the Act, which is published elsewhere in 
today's Federal Register.
    Both the northern Mexican and narrow-headed gartersnakes have been 
documented as highly vulnerable to effects from nonnative species as a 
result of their competition with gartersnakes for prey and effects from 
direct predation on the gartersnakes themselves (Rosen and Schwalbe 
1988, pp. 28-31, 32, 44-45). We conducted a broad review of all 
available scientific and commercial data, and have determined that 
nonnative species, such as bullfrogs, crayfish, and spiny-rayed fish, 
in the families Centrarchidae and Ictaluridae, continue to be the most 
significant threat to northern Mexican and narrow-headed gartersnakes 
throughout their respective ranges. Our analysis of the roles that the 
declines in the anuran prey base, declines in the native fish prey 
base, bullfrog predation, crayfish interactions, and effects from 
nonnative, spiny-rayed fish play with regard to the observed declines 
of the northern Mexican and narrow-headed gartersnakes is presented in 
detail in the proposed rule to list both species as threatened under 
the Act, which is

[[Page 41555]]

published elsewhere in today's Federal Register.

Primary Constituent Elements for Northern Mexican and Narrow-Headed 
Gartersnakes

    Under the Act and its implementing regulations, we are required to 
identify the physical or biological features essential to the 
conservation of northern Mexican and narrow-headed gartersnakes in 
areas occupied at the time of listing, focusing on the features' 
primary constituent elements (PCEs). We consider primary constituent 
elements to be the elements of physical or biological features that 
provide for a species' life-history processes and are essential to the 
conservation of the species.

Northern Mexican Gartersnake's PCEs

    Based on our current knowledge of the physical or biological 
features and habitat characteristics required to sustain the species' 
life-history processes, we determine that the primary constituent 
elements specific to northern Mexican gartersnakes are:
    (1) Aquatic or riparian habitat that includes:
    a. Perennial or spatially intermittent streams of low to moderate 
gradient that possess appropriate amounts of in-channel pools, off-
channel pools, or backwater habitat, and that possess a natural, 
unregulated flow regime that allows for periodic flooding or, if flows 
are modified or regulated, a flow regime that allows for adequate river 
functions, such as flows capable of processing sediment loads; or
    b. Lentic wetlands such as livestock tanks, springs, and cienegas; 
and
    c. Shoreline habitat with adequate organic and inorganic structural 
complexity to allow for thermoregulation, gestation, shelter, 
protection from predators, and foraging opportunities (e.g., boulders, 
rocks, organic debris such as downed trees or logs, debris jams, small 
mammal burrows, or leaf litter); and
    d. Aquatic habitat with characteristics that support a native 
amphibian prey base, such as salinities less than 5 parts per thousand, 
pH greater than or equal to 5.6, and pollutants absent or minimally 
present at levels that do not affect survival of any age class of the 
northern Mexican gartersnake or the maintenance of prey populations.
    (2) Adequate terrestrial space (600 ft (182.9 m) lateral extent to 
either side of bankfull stage) adjacent to designated stream systems 
with sufficient structural characteristics to support life-history 
functions such as gestation, immigration, emigration, and brumation 
(extended inactivity).
    (3) A prey base consisting of viable populations of native 
amphibian and native fish species.
    (4) An absence of nonnative fish species of the families 
Centrarchidae and Ictaluridae, bullfrogs (Lithobates catesbeianus), 
and/or crayfish (Orconectes virilis, Procambarus clarki, etc.), or 
occurrence of these nonnative species at low enough levels such that 
recruitment of northern Mexican gartersnakes and maintenance of viable 
native fish or soft-rayed, nonnative fish populations (prey) is still 
occurring.

Narrow-Headed Gartersnake's PCEs

    Based on our current knowledge of the physical or biological 
features and habitat characteristics required to sustain the species' 
life-history processes, we determine that the primary constituent 
elements specific to narrow-headed gartersnakes are:
    (1) Stream habitat, which includes:
    a. Perennial or spatially intermittent streams with sand, cobble, 
and boulder substrate and low or moderate amounts of fine sediment and 
substrate embeddedness, and that possess appropriate amounts of pool, 
riffle, and run habitat to sustain native fish populations;
    b. A natural, unregulated flow regime that allows for periodic 
flooding or, if flows are modified or regulated, a flow regime that 
allows for adequate river functions, such as flows capable of 
processing sediment loads;
    c. Shoreline habitat with adequate organic and inorganic structural 
complexity (e.g., boulders, cobble bars, vegetation, and organic debris 
such as downed trees or logs, debris jams), with appropriate amounts of 
shrub- and sapling-sized plants to allow for thermoregulation, 
gestation, shelter, protection from predators, and foraging 
opportunities; and
    d. Aquatic habitat with no pollutants or, if pollutants are 
present, levels that do not affect survival of any age class of the 
narrow-headed gartersnake or the maintenance of prey populations.
    (2) Adequate terrestrial space (600 ft (182.9 m) lateral extent to 
either side of bankfull stage) adjacent to designated stream systems 
with sufficient structural characteristics to support life-history 
functions such as gestation, immigration, emigration, and brumation.
    (3) A prey base consisting of viable populations of native fish 
species or soft-rayed, nonnative fish species.
    (4) An absence of nonnative fish species of the families 
Centrarchidae and Ictaluridae, bullfrogs (Lithobates catesbeianus), 
and/or crayfish (Orconectes virilis, Procambarus clarki, etc.), or 
occurrence of these nonnative species at low enough levels such that 
recruitment of narrow-headed gartersnakes and maintenance of viable 
native fish or soft-rayed, nonnative fish populations (prey) is still 
occurring.

Special Management Considerations or Protection

    When designating critical habitat, we assess whether the specific 
areas within the geographic area occupied by the species at the time of 
listing contain features which are essential to the conservation of the 
species and which may require special management considerations or 
protection.
    All areas proposed for designation as critical habitat will require 
some level of management to address the current and future threats to 
northern Mexican and narrow-headed gartersnakes and to maintain or 
restore the PCEs. Special management within proposed critical habitat 
will be needed to ensure these areas provide adequate water quantity, 
quality, and permanence or near permanence; cover (particularly in the 
presence of harmful nonnative species); an adequate prey base; and 
absence of or low numbers of harmful nonnative species that can affect 
population persistence. Activities that may be considered adverse to 
the conservation benefits of proposed critical habitat include those 
which: (1) Completely dewater or reduce the amount of water to 
unsuitable levels in proposed critical habitat; (2) result in a 
significant reduction of protective cover within proposed critical 
habitat when harmful nonnative species are present; (3) remove or 
significantly alter structural terrestrial features of proposed 
critical habitat that alter natural behaviors such as thermoregulation, 
brumation, gestation, and foraging; (4) appreciably diminish the prey 
base; and (5) directly promote increases in harmful nonnative species 
populations or result in the introduction of harmful nonnative species.
    Common examples of these activities may include, but are not 
limited to, various types of development, channelization, diversions, 
road construction, erosion control, bank stabilization, wastewater 
discharge, enhancement or expansion of human recreation opportunities, 
fish community renovations, and stocking of nonnative, spiny-rayed fish 
species or promotion of policies that directly or indirectly introduce 
harmful nonnative species as bait.
    The activities listed above are just a subset of examples that have 
the

[[Page 41556]]

potential to affect critical habitat and PCEs if they are conducted 
within designated units; however, some of these activities, when 
conducted appropriately, may be compatible with maintenance of adequate 
PCEs.

Criteria Used To Identify Critical Habitat

    As required by section 4(b)(2) of the Act, we use the best 
scientific data available to designate critical habitat. We review 
available information pertaining to the habitat requirements of the 
species. In accordance with the Act and its implementing regulation at 
50 CFR 424.12(e), we consider whether designating additional areas--
outside those currently occupied as well as those occupied at the time 
of listing--are necessary to ensure the conservation of the species. We 
are not currently proposing to designate any areas outside the 
geographic area considered occupied by the northern Mexican or narrow-
headed gartersnake because occupied areas are distributed in several 
subbasins and currently provide a distribution and configuration of 
habitat areas sufficient for the conservation of these species.
    To identify areas proposed for critical habitat for the northern 
Mexican and narrow-headed gartersnakes, we used a variety of sources 
which included riparian species survey reports, museum records, 
heritage data from State wildlife agencies, peer-reviewed literature, 
agency reports, interviews with species experts, and regional 
Geographic Information System (GIS) coverages. Some information sources 
were used heavily in determining the current and historical 
distributions of northern Mexican and narrow-headed gartersnakes such 
as Fitzgerald (1986, entire), Rosen and Schwalbe (1988, entire), Rosen 
et al. (2001, entire), and Holycross et al. (2006, entire), as they 
comprise the majority of rangewide survey information for these 
species. Hellekson (2012a, pers. comm.) was an important source of 
information pertaining to narrow-headed gartersnake status in New 
Mexico. In addition to reviewing gartersnake-specific survey reports, 
we also focused on survey reports for fish and amphibians as they 
captured important data on the existing community ecology that affects 
the status of these gartersnakes within their range.
    Critical habitat for both gartersnake species is being proposed in 
areas considered currently occupied. Survey information for both 
species is significantly lacking in many streams, and both species of 
gartersnake are cryptic, secretive, difficult to detect, quick to 
escape underwater, and capable of persisting in low or very low 
population densities that make positive detections nearly impossible in 
structurally complex habitat. Therefore, we considered factors such as 
the date of the last known records of either species in an area, as 
well as records of one or more native prey species. We used all records 
for each species that were dated 1980 or later because the 1980s marked 
the first systematic survey efforts for these species across their 
ranges (see Rosen and Schwalbe (1988, entire) and Fitzgerald (1986, 
entire)) and previous records were often dated several decades prior 
and may not as accurately represented the likelihood for occupation in 
current times. Additionally, in evaluating whether a site should be 
considered currently occupied by these gartersnake species, a record of 
a native prey species suggests that a source of prey may still be 
available to gartersnakes in areas invaded by harmful nonnative 
species. This provides evidence that either gartersnake may still 
likely occur in a given area if other sensitive, native, aquatic or 
riparian species are also present, despite limited or negative survey 
data. Specifically, for both species, we considered a stream or 
geographic area as occupied if it is within the historical range of the 
species, contains suitable habitat, and meets both of the following: 
(1) Has a last known record for either species dated 1980 or later, and 
(2) has at least one native prey species also present.
    The shape, size, and scope of proposed critical habitat can be 
evaluated in terms of its length (number of stream miles), width 
(lateral extent, in feet), or area (number of acres). With respect to 
length (in proposed designations based on flowing streams), the 
proposed areas were designed to provide sufficient aquatic and 
terrestrial habitat for normal behaviors of northern Mexican and 
narrow-headed gartersnakes of all age classes. In addition, with 
respect to width, we evaluated the lateral extent (terrestrial space) 
necessary to support the PCEs for northern Mexican and narrow-headed 
gartersnakes. The resulting designations take into account the 
naturally dynamic nature of riverine systems, floodplains, and riparian 
habitat (including adjacent upland areas) that are an integral part of 
these gartersnakes' ecology. For example, riparian areas are seasonally 
flooded habitats (i.e., wetlands) that are major contributors to a 
variety of functions vital to the gartersnakes' fish prey base within 
the associated stream channel (Brinson et al. 1981, pp. 2-61, 2-69, 2-
72, 2-75, 2-84 through 2-85; Federal Interagency Stream Restoration 
Working Group 1998, p. 2-61). Riparian areas filter runoff, absorb and 
gradually release floodwaters, recharge groundwater, maintain 
streamflow, protect stream banks from erosion, and provide shade and 
cover for fish and other aquatic species; all of these functions 
contribute to the physical quality of gartersnake habitat.
    Healthy riparian and adjacent upland areas help ensure water 
courses maintain the habitat important for aquatic species (e.g., see 
USFS 1979, pp. 18, 109, 158, 264, 285, 345; Middle Rio Grande 
Biological Interagency Team 1993, pp. 64, 89, 94; Castelle et al. 1994, 
pp. 279-281) that are prey for northern Mexican and narrow-headed 
gartersnakes, as well as for the snakes themselves. Habitat quality 
within the mainstem river channels in the historical range of the 
northern Mexican and narrow-headed gartersnakes is intrinsically 
related to the character of the floodplain and the associated 
tributaries, side channels, and backwater habitats that contribute to 
important habitat features that provide gartersnakes opportunities for 
foraging and basking in these reaches. We have determined that a 
relatively intact riparian area, along with periodic flooding in a 
generally natural pattern, is important for maintaining the PCEs 
necessary for long-term conservation of the northern Mexican and 
narrow-headed gartersnakes, as well as their primary prey species.
    The lateral extent (width) of riparian corridors fluctuates 
considerably between a stream's headwaters and its mouth. The 
appropriate width of riparian terrestrial habitat to protect stream 
function has been the subject of several studies and varies depending 
on the specific function (Castelle et al. 1994, pp. 879-881). Most 
Federal and State agencies generally consider a zone 75 to 150 ft (23 
to 46 m) wide on each side of a stream to be adequate (Natural Resource 
Conservation Service 1998, pp. 2-3; Moring et al. 1993, p. 204; Lynch 
et al. 1985, p. 164), although widths as wide as 500 ft (152 m) have 
been recommended for achieving flood attenuation benefits (U.S. Army 
Corps 1999, pp. 5-29). In most instances, however, adequate riparian 
space is primarily intended to reduce detrimental impacts to the stream 
from sources outside the river channel, such as pollutants, in adjacent 
areas. Consequently, while a riparian corridor 75 to 150 ft (23 to 46 
m) in width may protect water quality and provide some level of 
riparian habitat protection, a wider area would provide full

[[Page 41557]]

protection of riparian habitat because the stream itself can move 
within the floodplain in response to high flow events, and also provide 
terrestrial space required by northern Mexican and narrow-headed 
gartersnakes to engage in normal behaviors such as foraging, basking, 
gestation, brumation, establishing home ranges, dispersal, and so 
forth. Using telemetry data (Nowak 2006, pp. 19-21), the farthest 
distance a narrow-headed gartersnake has been detected from water is 
650 ft (200 m), while Rosen and Schwalbe (1988, p. 27) report observing 
a northern Mexican gartersnake at a distance of 330 ft (100 m) away 
from permanent water. Based on the literature, we expect the majority 
of terrestrial activity for both species occurs within 600 ft (182.9 m) 
of permanent water in lotic habitat.
    We believe a 600-ft (182.9-m) lateral extent to either side of 
bankfull stage will sufficiently protect the majority of important 
terrestrial habitat; provide brumation, gestation, and dispersal 
opportunities; and reduce the impacts of high flow events, thereby 
providing adequate protection to proposed critical habitat areas. We 
believe this width is necessary to accommodate stream properties such 
as meandering and high flows, and ensure these designations contain 
ample terrestrial space such that features essential to the 
conservation of these gartersnakes and their prey species can occur 
naturally. Bankfull stage is defined as the upper level of the range of 
channel-forming flows, which transport the bulk of available sediment 
over time. Bankfull stage is generally considered to be that level of 
stream discharge reached just before flows spill out onto the adjacent 
floodplain. The discharge that occurs at bankfull stage, in combination 
with the range of flows that occur over a length of time, govern the 
shape and size of the river channel (its geomorphology) (Rosgen 1996, 
pp. 2-2 to 2-4; Leopold 1997, pp. 62- 63, 66). The use of bankfull 
stage and 600 ft (182.9 m) on either side recognizes the naturally 
dynamic nature of riverine systems, recognizes that floodplains are an 
integral part of the stream ecosystem, and contains sufficient 
terrestrial space and associated features essential to the conservation 
of the northern Mexican and narrow-headed gartersnakes. Bankfull stage 
is not an ephemeral feature, meaning it does not disappear. Bankfull 
stage can always be determined and delineated for any stream we have 
designated as critical habitat. We acknowledge that the bankfull stage 
of any given stream may change depending on the magnitude of a flood 
event, but it is a definable and standard measurement for stream 
systems. Unlike trees, cliff faces, and other immovable habitat 
elements, stream systems provide habitat that is in constant change. 
Following high flow events, stream channels can move from one side of a 
canyon to the opposite side, for example.
    Designating critical habitat based on the location of the stream on 
a specific date is problematic for maintaining important habitat 
elements. For example, the area within such a designation could 
transition from providing aquatic habitat and prey to become a dry 
channel in a short period of time as a result of a high flow event and 
the subsequent shift in the location of the channel.
    We determined the 600-ft (182.9-m) lateral extent for several 
reasons. Although we considered using either the 100-year or 500-year 
floodplain, as defined by the Federal Emergency Management Agency, we 
found that the information was not readily available from the Federal 
Emergency Management Agency or from the U.S. Army Corps of Engineers 
for remote areas we are proposing for designation. Therefore, we 
selected the 600-ft (182.9-m) lateral extent, rather than some other 
delineation, for four biological reasons: (1) The biological integrity 
and natural dynamics of the river system and associated riparian 
habitat are maintained within this area (i.e., the floodplain and its 
riparian vegetation provide space for natural flooding patterns and 
latitude for necessary natural channel adjustments to maintain 
appropriate channel morphology and geometry, store water for slow 
release to maintain base flows, provide protected side channels and 
other protected areas, and allow the river to meander within its main 
channel in response to large flow events); (2) conservation of the 
adjacent riparian area also helps to provide important nutrient 
recharge to benefit the food web and protection from sediment and 
pollutants; (3) vegetated lateral zones are widely recognized as 
providing a variety of aquatic habitat functions and values (e.g., 
aquatic habitat for prey such as fish and other aquatic organisms and 
detritus for aquatic food webs) and help improve or maintain local 
water quality (see U.S. Army Corps of Engineers' Final Notice of 
Issuance and Modification of Nationwide Permits, March 9, 2000, 65 FR 
12818); and (4) a 600-ft (182.9-m) buffer contributes to the 
functioning of a river or stream system and provides adequate 
terrestrial space for normal northern Mexican and narrow-headed 
gartersnake behaviors, thereby supporting the PCEs needed for suitable 
northern Mexican and narrow-headed gartersnake habitat as described by 
the best available scientific and commercial information.
    When determining proposed critical habitat boundaries, we made 
every effort to avoid including large developed areas such as lands 
covered by buildings, pavement, and other structures because such lands 
lack physical or biological features for the northern Mexican and 
narrow-headed gartersnakes. While reptiles, including gartersnakes, may 
use artificial materials for cover, areas that have been significantly 
altered by construction-related development are not generally suitable 
for gartersnakes or their prey species. The scale of the maps we 
prepared under the parameters for publication within the Code of 
Federal Regulations may not reflect the exclusion of such developed 
lands. Any such lands inadvertently left inside critical habitat 
boundaries shown on the maps of this proposed rule have been excluded 
by text in the proposed rule and are not proposed for designation as 
critical habitat. Therefore, if critical habitat is finalized as 
proposed, a Federal action involving these lands would not trigger 
section 7 consultation with respect to critical habitat and the 
requirement of no adverse modification, unless the specific action 
would affect the physical or biological features in the adjacent 
critical habitat.
    We are proposing for designation of critical habitat lands that we 
have determined are occupied at the time of listing and contain 
sufficient elements of physical or biological features to support life-
history processes essential for the conservation of the species.
    Units are proposed for designation based on sufficient elements of 
physical or biological features being present to support the northern 
Mexican and narrow-headed gartersnakes' life-history processes. Some 
units contain all of the identified elements of physical or biological 
features and support multiple life-history processes. Some segments 
contain only some elements of the physical or biological features 
necessary to support the northern Mexican and narrow-headed 
gartersnakes' particular use of that habitat.
    The critical habitat designation is defined by the maps, as 
modified by any accompanying regulatory text, presented at the end of 
this document in the Proposed Regulation Promulgation section. We 
include more detailed information on the proposed boundaries of the 
critical habitat designation in the preamble of this document. We will 
make the coordinates or plot points or both on which each map is based

[[Page 41558]]

available to the public on http://www.regulations.gov at Docket No. 
FWS-R2-ES-2013-0022, on our Internet site at http://www.fws.gov/southwest/es/arizona, and at the field office responsible for the 
designation (see FOR FURTHER INFORMATION CONTACT above).

Proposed Critical Habitat Designation

    We are proposing 14 units as critical habitat for the northern 
Mexican gartersnake and 6 units as critical habitat for the narrow-
headed gartersnake. The critical habitat areas we describe below 
constitute our current best assessment of areas that meet the 
definition of critical habitat for the northern Mexican and narrow-
headed gartersnakes. The 14 units we propose as critical habitat for 
the northern Mexican gartersnake include lands in the following areas: 
(1) Gila River Mainstem; (2) Mule Creek; (3) Bill Williams River; (4) 
Agua Fria River Subbasin; (5) Upper Salt River Subbasin; (6) Tonto 
Creek; (7) Verde River Subbasin; (8) Upper Santa Cruz River Subbasin; 
(9) Redrock Canyon; (10) Buenos Aires National Wildlife Refuge; (11) 
Cienega Creek Subbasin; (12) San Pedro River Subbasin; (13) Babocomari 
River Subbasin; and (14) the San Bernardino National Wildlife Refuge 
(SBNWR). The six units we propose as critical habitat for the narrow-
headed gartersnake are: (1) Upper Gila River Subbasin; (2) Middle Gila 
River Subbasin; (3) San Francisco River Subbasin; (4) Salt River 
Subbasin; (5) Tonto Creek Subbasin; and (6) Verde River Subbasin. All 
units for both species are considered occupied. It is important to 
recognize that while all units for both species are considered 
occupied, the majority of populations in these proposed critical 
habitat units are currently considered likely not viable into the 
future. We have concluded that 83 percent of the northern Mexican 
gartersnake's populations in the United States and 76 percent of the 
narrow-headed gartersnake's populations occur at low densities and are 
likely not viable. Please see Appendix A (available at http://www.regulations.gov under Docket No. FWS-R2-ES-2013-0022) for detailed 
information on occupancy status.

                            Table 3a--Land Ownership for Proposed Critical Habitat Units for the Northern Mexican Gartersnake
              [Area estimates reflect all land within critical habitat unit boundaries. County-owned lands are considered as private lands]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Land ownership by type
              Unit                      Subunit      --------------------------------------------------------------------------------    Size of unit
                                                            Federal              State              Tribal              Private
--------------------------------------------------------------------------------------------------------------------------------------------------------
Upper Gila River................  ..................  10,845 ac (4,389    467 ac (189 ha)...  ..................  9,822 ac (3,975     21,135 ac (8,553
                                                       ha).                                                        ha).                ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  10,845 ac (4,389    467 ac (189 ha)...  ..................  9,822 ac (3,975     21,135 ac (8,553
                                                       ha).                                                        ha).                ha).
Mule Creek......................  ..................  1,327 ac (537 ha).  ..................  ..................  1,253 ac (507 ha).  2,579 ac (1044
                                                                                                                                       ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  1,327 ac (537 ha).  ..................  ..................  1,253 ac (507 ha).  2,579 ac (1044
                                                                                                                                       ha).
Bill Williams River.............  ..................  3,820 ac (1,546     516 ac (209 ha)...  ..................  1,076 ac (435 ha).  5,412 ac (2,190
                                                       ha).                                                                            ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  3,820 ac (1,546     516 ac (209 ha)...  ..................  1,076 ac (435 ha).  5,412 ac (2,190
                                                       ha).                                                                            ha).
Agua Fria River Subbasin........  Agua Fria River     3,313 ac (1,341     918 ac (372 ha)...  ..................  2,758 ac (1,116     6,989 ac (2,828
                                   Mainstem.           ha).                                                        ha).                ha).
                                  Little Ash Creek..  877 ac (355 ha)...  ..................  ..................  80 ac (32 ha).....  957 ac (387 ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  4,010 ac (1,696     918 ac (372 ha)...  ..................  2,838 ac (1,148     7,946 ac (3,215
                                                       ha).                                                        ha).                ha).
Upper Salt River Subbasin.......  Black River.......  2,632 ac (1,065     ..................  13,760 ac (5,569    ..................  16,392 ac (6,634
                                                       ha).                                    ha).                                    ha).
                                  Big Bonito Creek..  ..................  ..................  5,826 ac (2,358     ..................  5,826 ac (2,358
                                                                                               ha).                                    ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  2,632 ac (1,065     ..................  19,586 ac (7,927    ..................  22,218 ac (8,991
                                                       ha).                                    ha).                                    ha).
Tonto Creek.....................  ..................  7,766 ac (3,143     ..................  ..................  1,170 ac (474 ha).  8,936 ac (3,616
                                                       ha).                                                                            ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  7,766 ac (3,143     ..................  ..................  1,170 ac (474 ha).  8,936 ac (3,616
                                                       ha).                                                                            ha).
Verde River Subbasin............  Upper Verde River.  13,903 ac (5,626    1,209 ac (489 ha).  192 ac (78 ha)....  5,223 ac (2,114     20,526 ac (8,307
                                                       ha).                                                        ha).                ha).
                                  Oak Creek.........  1,873 ac (758 ha).  274 ac (111 ha)...  ..................  3,386 ac (1,370     5,533 ac (2,239
                                                                                                                   ha).                ha).
                                  Spring Creek......  2,572 ac (1,041     188 ac (76 ha)....  ..................  371 ac (150 ha)...  3,131 ac (1,267
                                                       ha).                                                                            ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  18,348 ac (7,425    1,671 ac (676 ha).  192 ac (78 ha)....  8,980 ac (3,634     29,191 ac (11,813
                                                       ha).                                                        ha).                ha).
Upper Santa Cruz River Subbasin.  ..................  77,387 ac (31,318   3,969 ac (1,606     ..................  32,538 ac (13,168   113,895 ac (46,092
                                                       ha).                ha).                                    ha).                ha).
                                 -----------------------------------------------------------------------------------------------------------------------

[[Page 41559]]

 
    Unit Total..................  ..................  77,387 ac (31,318   3,969 ac (1,606     ..................  32,538 ac (13,168   113,895 ac (46,092
                                                       ha).                ha).                                    ha).                ha).
Redrock Canyon..................  ..................  1,423 ac (576 ha).  ..................  ..................  549 ac (222 ha)...  1,972 ac (798 ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  1,423 ac (576 ha).  ..................  ..................  549 ac (222 ha)...  1,972 ac (798 ha).
Buenos Aires National Wildlife    ..................  117,313 ac (47,475  ..................  ..................  ..................  117,313 ac (47,475
 Refuge.                                               ha).                                                                            ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  117,313 ac (47,475  ..................  ..................  ..................  117,313 ac (47,475
                                                       ha).                                                                            ha).
Cienega Creek Subbasin..........  Cienega Creek.....  24 ac (10 ha).....  1,078 ac (436 ha).  ..................  11 ac (4 ha)......  1,113 ac (450 ha).
                                  Las Cienegas        39,913 ac (16,152   5,105 ac (2,066     ..................  1 ac (<1 ha)......  45,020 ac (18,219
                                   National            ha).                ha).                                                        ha).
                                   Conservation Area.
                                  Cienega Creek       ..................  ..................  ..................  4,260 ac (1,724     4,260 ac (1,724
                                   Natural Preserve.                                                               ha).                ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  39,937 ac (16,162   6,183 ac (2,502     ..................  4,272 ac (1,728     50,393 ac (20,393
                                                       ha).                ha).                                    ha).                ha).
San Pedro River Subbasin........  San Pedro River...  6,973 ac (2,822     1,163 ac (470 ha).  76 ac (31 ha).....  14,456 ac (5,850    22,669 ac (9,174
                                                       ha).                                                        ha).                ha).
                                  Bear Canyon Creek.  639 ac (259 ha)...  ..................  ..................  383 ac (155 ha)...  1,022 ac (414 ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  7,612 ac (3,081     1,163 ac (470 ha).  76 ac (31 ha).....  14,839 ac (6,005    23,690 ac (9,587
                                                       ha).                                                        ha).                ha).
Babocomari River Subbasin.......  Babocomari River/   625 ac (253 ha)...  56 ac (23 ha).....  ..................  2,773 ac (1,122     3,454 ac (1,398
                                   Cienega.                                                                        ha).                ha).
                                  Post Canyon.......  431 ac (175 ha)...  ..................  ..................  363 ac (147 ha)...  795 ac (322 ha).
                                  O'Donnell Canyon..  124 ac (50 ha)....  ..................  ..................  274 ac (111 ha)...  398 ac (161 ha).
                                  Turkey Creek......  888 ac (359 ha)...  2 ac (1 ha).......  ..................  788 ac (319 ha)...  1,678 ac (679 ha).
                                  Appleton-Whittell   5,283 ac (2,138     ..................  ..................  2,515 ac (1,018     7,798 ac (3,156
                                   Research Ranch.     ha).                                                        ha).                ha).
                                  Canelo Hills        ..................  ..................  ..................  213 ac (86 ha)....  213 ac (86 ha).
                                   Cienega Preserve.
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  7,351 ac (2,975     58 ac (24 ha).....  ..................  6,926 ac (2,803     14,334 ac (5,801
                                                       ha).                                                        ha).                ha).
San Bernardino National Wildlife  ..................  2,387 ac (966 ha).  ..................  ..................  ..................  2,387 ac (966 ha).
 Refuge.
                                 -----------------------------------------------------------------------------------------------------------------------
        Total...................  ..................  302,338 ac          14,966 ac (6,057    19,855 ac (8,035    84,263 ac (34,100   421,423 ac
                                                       (122,352 ha).       ha).                ha).                ha).                (170,544 ha).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Numbers may not sum due to rounding.


                               Table 3b--Land Ownership for Proposed Critical Habitat Units for Narrow-Headed Gartersnakes
              [Area estimates reflect all land within critical habitat unit boundaries. County-owned lands are considered as private lands]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Land ownership by type
              Unit                      Subunit      --------------------------------------------------------------------------------    Size of unit
                                                            Federal              State              Tribal              Private
--------------------------------------------------------------------------------------------------------------------------------------------------------
Upper Gila River Subbasin.......  Gila River........  10,845 ac (4,389    467 ac (189 ha)...  ..................  9,822 ac (3,975     21,135 ac (8,553
                                                       ha).                                                        ha).                ha).
                                  East Fork Gila      2,929 ac (1,185     ..................  ..................  649 ac (263 ha)...  3,579 ac (1,148
                                   River.              ha).                                                                            ha).
                                  West Fork Gila      4,793 ac (1,940     ..................  ..................  376 ac (152 ha)...  5,169 ac (2,092
                                   River.              ha).                                                                            ha).
                                  Middle Fork Gila    4,875 ac (1,973     ..................  ..................  89 ac (36 ha).....  4,964 ac (2,009
                                   River.              ha).                                                                            ha).

[[Page 41560]]

 
                                  Black Canyon......  3,465 ac (1,402     ..................  ..................  38 ac (15 ha).....  3,503 ac (1,418
                                                       ha).                                                                            ha).
                                  Diamond Creek.....  2,995 ac (1,212     ..................  ..................  550 ac (223 ha)...  3,545 ac (1,435
                                                       ha).                                                                            ha).
                                  Gilita Creek......  1,704 ac (690 ha).  ..................  ..................  ..................  1,704 ac (690 ha).
                                  Iron Creek........  1,731 ac (701 ha).  ..................  ..................  ..................  1,731 ac (701 ha).
                                  Little Creek......  2,223 ac (900 ha).  ..................  ..................  13 ac (5 ha)......  2,236 ac (905 ha).
                                  Turkey Creek......  2,338 ac (946 ha).  ..................  ..................  ..................  2,338 ac (946 ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  37,898 ac (15,338   467 ac (189 ha)...  ..................  11,537 ac (4,669    49,903 ac (20,195
                                                       ha).                                                        ha).                ha).
Middle Gila River Subbasin......  Gila River........  422 ac (171 ha)...  ..................  ..................  11 ac (4 ha)......  432 ac (175 ha).
                                  Eagle Creek.......  2,016 ac (816 ha).  54 ac (22 ha).....  2,258 ac (1,035     3,754 ac (1,519     8,382 ac (3,392
                                                                                               ha).                ha).                ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  2,438 ac (987 ha).  54 ac (22 ha).....  2,258 ac (1,035     3,765 ac (1,523     8,814 ac (3,567
                                                                                               ha).                ha).                ha).
San Francisco River Subbasin....  San Francisco       15,661 ac (6,338    216 ac (88 ha)....  ..................  7,300 ac (2,954     23,178 ac (9,380
                                   River.              ha).                                                        ha).                ha).
                                  Blue River........  6,484 ac (2,624     ..................  ..................  948 ac (383 ha)...  7,432 ac (3,007
                                                       ha).                                                                            ha).
                                  Campbell Blue       2,888 ac 1,169 ha)  ..................  ..................  120 ac (49 ha)....  3,008 ac (1,217
                                   Creek.                                                                                              ha).
                                  Dry Blue Creek....  1,320 ac (534 ha).  ..................  ..................  ..................  1,320 ac (534 ha).
                                  South Fork Negrito  1,383 ac (560 ha).  ..................  ..................  100 ac (40 ha)....  1,483 ac (600 ha).
                                   Creek.
                                  Saliz Creek.......  852 ac (345 ha)...  ..................  ..................  247 ac (100 ha)...  1,099 ac (445 ha).
                                  Tularosa River....  1,875 ac (759 ha).  ..................  ..................  2,852 ac (1,154     4,728 ac (1,913
                                                                                                                   ha).                ha).
                                  Whitewater Creek..  2,282 ac (923 ha).  ..................  ..................  547 ac (221 ha)...  2,289 ac (1,145
                                                                                                                                       ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  32,745 ac (13,252   216 ac (88 ha)....  ..................  12,114 ac (4,901    45,075 ac (18,241
                                                       ha).                                                        ha).                ha).
Upper Salt River Subbasin.......  Salt River........  5,342 ac (2,162     ..................  7,502 ac (3,036     33 ac (13 ha).....  12,877 ac (5,211
                                                       ha).                                    ha).                                    ha).
                                  White River.......  ..................  ..................  2,588 ac (1,047     ..................  2,588 ac (1,047
                                                                                               ha).                                    ha).
                                  Canyon Creek......  1,182 ac (478 ha).  ..................  6,160 ac (2,493     3 ac (1 ha).......  7,346 ac (2,973
                                                                                               ha).                                    ha).
                                  Carrizo Creek.....  158 ac (64 ha)....  ..................  8,875 ac (3,592     ..................  9,033 ac (1,229
                                                                                               ha).                                    ha).
                                  Cibecue Creek.....  ..................  ..................  6,669 ac (2,699     ..................  6,669 ac (2,699
                                                                                               ha).                                    ha).
                                  Diamond Creek.....  ..................  ..................  3,117 ac (1,261     ..................  3,117 ac (1,261
                                                                                               ha).                                    ha).
                                  Black River.......  2,632 ac (1,065     ..................  13,752 ac (5,565    ..................  16,384 ac (6,630
                                                       ha).                                    ha).                                    ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  9,314 ac (3,769     ..................  48,663 ac (19,693   36 ac (14 ha).....  58,014 ac (23,478
                                                       ha).                                    ha).                                    ha).
Tonto Creek Subbasin............  Haigler Creek.....  2,831 ac (1,146     ..................  ..................  206 ac (83 ha)....  3,037 ac (1229
                                                       ha).                                                                            ha).
                                  Houston Creek.....  1,747 ac (707 ha).  ..................  ..................  299 ac (121 ha)...  2,046 ac (828 ha).
                                  Tonto Creek.......  7,017 ac (2,840     ..................  ..................  696 ac (282 ha)...  7,712 ac (3,121
                                                       ha).                                                                            ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  11,595 ac (4,693    ..................  ..................  1,201 ac (486 ha).  12,795 ac (5,178
                                                       ha).                                                                            ha).
Verde River Subbasin............  Verde River.......  12,098 ac (4,896    1,209 ac (489 ha).  192 ac (78 ha)....  5,223 ac (2114 ha)  18,721 ac (7576
                                                       ha).                                                                            ha).
                                  Oak Creek.........  3,340 ac (1,352     328 ac (133 ha)...  ..................  3,701 ac (1,498     7,369 ac (2,982
                                                       ha).                                                        ha).                ha).
                                  West Fork Oak       2,137 ac (865 ha).  ..................  ..................  ..................  2,137 ac (865 ha).
                                   Creek.

[[Page 41561]]

 
                                  East Verde River..  6,682 ac (2,704     ..................  ..................  678 ac (274 ha)...  7,360 ac (2,978
                                                       ha).                                                                            ha).
                                 -----------------------------------------------------------------------------------------------------------------------
    Unit Total..................  ..................  24,257 ac (9,817    1,537 ac (622 ha).  192 ac (78 ha)....  9,602 ac (3,886     35,586 ac (14,401
                                                       ha).                                                        ha).                ha).
                                                     ---------------------------------------------------------------------------------------------------
        Total...................  ..................  118,247 ac (47,853  2,275 ac (921 ha).  51,415 ac (20,807   38,253 ac (15,480   210,189 ac (85,060
                                                       ha).                                    ha).                ha).                ha).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Numbers may not sum due to rounding.

    The following are brief descriptions of all units and our reasoning 
as to why they meet the definition of critical habitat for the northern 
Mexican gartersnake or the narrow-headed gartersnake.

Northern Mexican Gartersnake

Upper Gila River Unit
    The Upper Gila River Unit is generally located in southwestern New 
Mexico in the Gila Wilderness of the Gila National Forest in Hidalgo 
and Grant Counties, New Mexico, and eastern Arizona in Graham County. 
This unit consists of a total of 21,135 acres (8,553 ha) along 148 
stream mi (239 km) of proposed critical habitat along the Gila River 
mainstem. Land ownership or land management within this unit consists 
of lands managed by the U.S. Forest Service, New Mexico Department of 
Game and Fish, State Trust lands, and private ownership. The identified 
area described in the Upper Gila River Unit has records since 1980 for 
northern Mexican gartersnakes, and is within the geographical area 
currently occupied by the species. We are proposing the area in this 
unit because it is occupied by the species and because it contains 
essential physical or biological features that may require special 
management considerations or protection. The following narrative 
describes the area proposed as critical habitat in the Upper Gila River 
Unit.
    We are proposing to designate 21,135 acres (8,553 ha) of critical 
habitat along 148.2 stream mi (238.6 km) of the upper Gila River, from 
its confluence with the San Francisco River in Graham County, Arizona, 
upstream to its confluence with East Fork Gila River and Black Canyon 
in Catron County, New Mexico. The Upper Gila River Unit is primarily 
privately owned, with additional parcels managed by the Gila National 
Forest, the New Mexico Department of Game and Fish, and the Arizona and 
New Mexico State Land Departments. Several reaches of the Gila River in 
New Mexico have been adversely affected by channelization and 
diversions, which have reduced or eliminated baseflow. As a whole, 
however, this unit contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics) and 2 (terrestrial 
habitat characteristics), but PCEs 3 (prey base) and 4 (absence or low 
level of harmful nonnative species) are deficient. Special management 
may be required to maintain or develop the physical or biological 
features, including the elimination or reduction of harmful nonnative 
species and improving the status of ranid frog populations. Lands 
within The Nature Conservancy's Gila Riparian Preserve in this unit are 
being considered for exclusion from the final rule for critical habitat 
under section 4(b)(2) of the Act (see Application of Section 4(b)(2) of 
the Act below).
    The Upper Gila River Unit is proposed as critical habitat for the 
northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. Some reaches of the Gila River have been adversely affected by 
channelization and water diversions. There remains the potential for 
the construction of Hooker Dam in the reach of the Gila River above 
Mogollon Creek and below Turkey Creek as part of the Central Arizona 
Project, which would adversely affect both the physical habitat for 
northern Mexican gartersnakes as well as their prey base, but this 
project remains in deferment status. The physical or biological 
features in this unit may require special management consideration due 
to competition with, and predation by, harmful nonnative species that 
are present in this unit; water diversions; channelization; potential 
for high-intensity wildfires; and human development of areas adjacent 
to proposed critical habitat.
Mule Creek Unit
    The Mule Creek Unit is generally located in southwestern New Mexico 
in the vicinity of Mule Creek, New Mexico (Grant and Catron Counties). 
This unit consists of a total of 2,579 acres (1,044 ha) along 19 stream 
mi (30 km) of proposed critical habitat along Mule Creek. Land 
ownership or land management within this unit consists of lands managed 
by the U.S. Forest Service and private ownership. The identified area 
described in the Mule Creek Unit has records for northern Mexican 
gartersnakes since 1980, and is considered as being within the 
geographical area currently occupied by the species. We are proposing 
this area under section 3(5)(A)(i) of the Act because it is occupied by 
the species and because it contains essential physical or biological 
features that may require special management considerations or 
protection. The following narrative describes the area proposed as 
critical habitat in the Mule Creek Unit.
    We are proposing to designate 2,579 acres (1,044 ha) of critical 
habitat along 18.7 stream mi (30.1 km) of Mule Creek, from its 
confluence with the San Francisco River, upstream to its origin 
northwest of North Sawmill Canyon in Grant and Catron Counties, New 
Mexico. The Mule Creek Subunit is managed by the Gila National Forest, 
with additional parcels under private ownership. Mule Creek supports 
native fish and supports an adequate amount of suitable aquatic and 
terrestrial habitat with the appropriate characteristics to support the 
northern Mexican gartersnake. However, the habitat quality is somewhat 
compromised by the presence of bullfrogs, which are known to have a 
negative association

[[Page 41562]]

with northern Mexican gartersnakes. This subunit contains sufficient 
physical or biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 3 (prey 
base), but PCE 4 (absence or low level of harmful nonnative species) is 
deficient. Special management may be required to maintain or develop 
the physical or biological features, including management to remove or 
reduce bullfrogs.
    The Mule Creek Unit is proposed as critical habitat for the 
northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit; potential 
for high-intensity wildfires; and human development of areas adjacent 
to proposed critical habitat.
Bill Williams River Unit
    The Bill Williams River Unit is generally located in western 
Arizona, northeast of Parker, Arizona, in La Paz and Mohave Counties. 
This unit consists of a total of 5,412 acres (2,190 ha) along 36 stream 
mi (58 km) of proposed critical habitat along the Bill Williams River, 
Arizona. We are proposing to designate the reach of the Bill Williams 
River running from its confluence with Lake Havasu, upstream to Alamo 
Lake Dam. The Bill Williams River Unit occurs on lands primarily 
managed by the U.S. Bureau of Land Management. Remaining land 
management and ownership includes the Bill Williams National Wildlife 
Refuge, U.S. Department of Defense lands, Arizona State Land 
Department, and private land owners. All identified areas described in 
this unit have records for northern Mexican gartersnakes since 1980, 
and all identified areas are considered as being within the 
geographical area currently occupied by the species. We are proposing 
this unit under section 3(5)(A)(i) of the Act because it is occupied by 
the species and because it contains essential physical or biological 
features that may require special management considerations or 
protection. This unit contains adequate populations of lowland leopard 
frogs, but native fish appear to be absent. Crayfish and several 
species of nonnative, spiny-rayed fish maintain robust populations in 
this reach. Within this unit, PCEs 1 (aquatic habitat characteristics) 
and 2 (terrestrial habitat characteristics) are present, but PCEs 3 
(prey base) and 4 (absence or low level of harmful nonnative species) 
are deficient. Special management may be required to maintain or 
develop the physical or biological features, including the elimination 
or reduction of crayfish and nonnative, spiny-rayed fish, as well as 
the prevention of a bullfrog invasion.
    The Bill Williams River Unit is proposed as critical habitat for 
the northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit and flood-
control projects.
Agua Fria River Subbasin Unit
    The Agua Fria River Subbasin Unit is generally located in central 
Arizona, paralleling Interstate 17, just north of the Phoenix 
metropolitan area, in Yavapai County, Arizona. This unit consists of a 
total of 7,946 acres (3,215 ha) along 56 stream mi (91 km) of proposed 
critical habitat along the Agua Fria River and Little Ash Creek. Land 
ownership or land management within this unit consists of lands managed 
by the U.S. Bureau of Land Management, U.S. Forest Service, State Trust 
lands, and private ownership. All identified areas described in the 
Agua Fria River Subbasin Unit have records since 1980 for northern 
Mexican gartersnakes, and all are considered as being within the 
geographical area currently occupied by the species. We are proposing 
the areas in this unit under section 3(5)(A)(i) of the Act because they 
are essential for the conservation of the northern Mexican gartersnake. 
The following narratives describe all of the subunits proposed as 
critical habitat in the Agua Fria River Subbasin Unit.
    Agua Fria River Mainstem Subunit. We are proposing to designate 
6,989 acres (2,828 ha) of critical habitat along 49.1 stream mi (80.0 
km) of the Agua Fria River mainstem, from its confluence with Squaw 
Creek east of Black Canyon City, upstream to its confluence with the 
unnamed drainage south of Highway 169 in Dewey, Arizona (Yavapai 
County). Also included in this subunit are 88 acres (36 ha) of the 
Arizona Game and Fish Department's Horseshoe Ranch property, which is 
located along the Agua Fria River at its confluence with Indian Creek. 
The Agua Fria River Mainstem Subunit is primarily privately owned or 
managed by the U.S. Bureau of Land Management, with additional parcels 
managed by the Arizona State Land Department. The Agua Fria River 
contains nonnative, soft-rayed fish and lowland leopard frogs as prey, 
and contains an adequate amount of suitable aquatic and terrestrial 
habitat with the appropriate characteristics to support the northern 
Mexican gartersnake. However, the dominance of crayfish, bullfrogs, and 
nonnative, spiny-rayed fish in some reaches negatively affects the 
proposed subunit's suitability for northern Mexican gartersnakes. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including management to remove or reduce crayfish, bullfrogs, and 
nonnative, spiny-rayed fish. Lands within the Arizona Game and Fish 
Department's Horseshoe Ranch property are being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Little Ash Creek Subunit. We are proposing to designate 957 acres 
(387 ha) of critical habitat along 6.7 stream mi (10.7 km) of Little 
Ash Creek, from the confluence of Ash Creek, upstream to its confluence 
with an unnamed drainage east of the bridge over Dugas Road in Yavapai 
County, Arizona. The Little Ash Creek Subunit is primarily managed by 
the Prescott National Forest and U.S. Bureau of Land Management with 
additional parcels under Arizona State Land Department and private 
ownership. According to GIS analysis, Little Ash Creek supports 
populations of lowland leopard frogs and two species of native fish, 
and contains adequate amount of suitable aquatic and terrestrial 
habitat with the appropriate characteristics to support the northern 
Mexican gartersnake, but the dominance of crayfish, bullfrogs, and 
nonnative, spiny-rayed fish in some reaches negatively affects the 
suitability for northern Mexican gartersnakes. This subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
3 (prey base), but PCE 4 (absence or low level of harmful nonnative 
species) is deficient. Special management may be required to maintain 
or develop the

[[Page 41563]]

physical or biological features, including management against crayfish, 
bullfrogs, and nonnative, spiny-rayed fish.
    The Agua Fria Subbasin Unit is proposed as critical habitat for the 
northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due primarily to competition with, and 
predation by, harmful nonnative species that are present in this unit 
and to a lesser extent human development of areas adjacent to proposed 
critical habitat.
Upper Salt River Subbasin Unit
    The Upper Salt River Subbasin Unit is generally located along the 
Mogollon Rim in east-central Arizona, and includes portions of Gila, 
Graham, Apache, Navajo, and Greenlee Counties. The Upper Salt River 
Subbasin Unit largely includes remote, rural areas, generally under the 
ownership and management of tribal governments, specifically the White 
Mountain Apache and San Carlos Apache Tribes. This unit consists of a 
total of 22,218 acres (8,991 ha) along 156 stream mi (251 km) of 
proposed critical habitat along the Black River and Big Bonito Creek. 
Land ownership or land management within this unit consists of tribal 
lands and those managed by the U.S. Forest Service. All identified 
areas described in the Salt River Subbasin Unit have records since 1980 
for northern Mexican gartersnakes, and all identified areas are 
considered as being within the geographical area currently occupied by 
the species. We are proposing the areas in this unit under section 
3(5)(A)(i) of the Act because they are occupied by the species and 
because they contain sufficient amounts of the essential physical or 
biological features that may require special management considerations 
or protection. The following narratives describe all of the subunits 
proposed as critical habitat in the Upper Salt River Subbasin Unit.
    Black River Subunit. We are proposing to designate 16,392 acres 
(6,634 ha) of critical habitat along 114.4 stream mi (184.0 km) of the 
Black River from its confluence with the Salt and White rivers, 
upstream to the confluence with the East and West Forks of the Black 
River. The Black River Drainage Subunit occurs in Apache, Gila, Graham, 
Greenlee, and Navajo Counties, Arizona. The Black River drainage is 
primarily owned by the White Mountain Apache and San Carlos Apache 
Tribes, with additional parcels managed by the Apache-Sitgreaves 
National Forest. Water in the Black River is diverted for use at the 
Morenci Mine, which may affect baseflow. This subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
PCE 3 (prey base), but PCE 4 (absence or low level of harmful nonnative 
species) is deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
elimination or reduction of crayfish and possibly nonnative, spiny-
rayed fish, as well as to maintain adequate base flows in the Black 
River. Lands owned by the White Mountain Apache and San Carlos Apache 
Tribes are being considered for exclusion from the final rule for 
critical habitat under section 4(b)(2) of the Act (see Application of 
Section 4(b)(2) of the Act below).
    Big Bonito Creek Subunit. We are proposing to designate 5,826 acres 
(2,358 ha) of critical habitat along 41.5 stream mi (66.8 km) of Big 
Bonito Creek, from its confluence with the Black River east of the 
mouth of Sawmill Canyon, upstream to its origin southwest of Mount 
Baldy in the White Mountains, in Apache and Navajo Counties, Arizona. 
Big Bonito Creek is solely owned by the White Mountain Apache Tribe. 
This subunit contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics) and 2 (terrestrial 
habitat characteristics), but PCEs 3 (prey base) and 4 (absence or low 
level of harmful nonnative species) are deficient. Special management 
may be required to maintain or develop the physical or biological 
features, including the elimination or reduction of crayfish and 
nonnative, spiny-rayed fish, as well as management to support a native 
prey base for northern Mexican gartersnakes. This subunit is being 
considered for exclusion from the final rule for critical habitat under 
section 4(b)(2) of the Act (see Application of Section 4(b)(2) of the 
Act below).
    The Upper Salt River Subbasin Unit is proposed as critical habitat 
for the northern Mexican gartersnake because it is occupied at the time 
of listing and largely contains sufficient physical or biological 
features to support life-history functions essential for the 
conservation of the species. However, the 2011 Wallow Fire adversely 
affected a large proportion of the Black River drainage, and subsequent 
ash and sediment flows have likely resulted in a depressed fish 
community, which could stress resident northern Mexican gartersnake 
populations in the short to medium term. The physical or biological 
features in this unit may require special management consideration due 
to competition with, and predation by, harmful nonnative species that 
are present in this unit; water diversions; potential for high-
intensity wildfires; and human development of areas adjacent to 
proposed critical habitat.
Tonto Creek Unit
    The Tonto Creek Unit is generally located southeast of Payson, 
Arizona, and northeast of the Phoenix metropolitan area, in Gila 
County. We are proposing to designate 8,936 acres (3,616 ha) of 
critical habitat along 65.1 stream mi (104.7 km) of Tonto Creek, from 
its confluence with Roosevelt Lake upstream to its origin northeast of 
Tonto Spring, south of Rim Road, in Gila County, Arizona. Tonto Creek 
occurs predominately on lands managed by the Tonto National Forest. The 
remaining landownership is private. Therefore, we are proposing this 
unit under section 3(5)(A)(i) of the Act because it is occupied by the 
species and because it contains sufficient amounts of the essential 
physical or biological features that may require special management 
considerations or protection. Some reaches along Tonto Creek experience 
seasonal drying as a result of regional groundwater pumping, while 
others are affected by diversions or existing or planned flood control 
projects. Development along private reaches of Tonto Creek may also 
affect terrestrial characteristics of northern Mexican gartersnake 
habitat. Mercury has been detected in fish samples within Tonto Creek, 
and further research is necessary to determine if mercury is 
bioaccumulating in the resident food chain. In general, this unit 
contains sufficient physical or biological features, including PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish, bullfrogs, and 
nonnative, spiny-rayed fish, as well as improve base flows.
    The Tonto Creek Unit is proposed as critical habitat for the 
northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this

[[Page 41564]]

unit may require special management consideration due to competition 
with, and predation by, harmful nonnative species that are present in 
this unit; water diversions; flood-control projects; and development of 
areas adjacent to or within proposed critical habitat.
Verde River Subbasin Unit
    The Verde River Subbasin Unit is generally located southwest of 
Paulden, Arizona, and northwest of Payson, Arizona, in Coconino, Gila, 
and Yavapai Counties. This unit consists of a total of 29,191 acres 
(11,813 ha) along approximately 201 stream mi (323 km) of proposed 
critical habitat along the Verde River, Oak Creek, and Spring Creek. 
Lands within this unit consist of federally managed lands, State Trust 
lands and other State-managed lands, tribal lands, and privately owned 
lands. All identified areas described in the Verde River Subbasin Unit 
have records for northern Mexican gartersnakes, and all identified 
areas are considered as being currently within the geographical area 
occupied by the species. Therefore, we are proposing the areas in this 
unit under section 3(5)(A)(i) of the Act because they are occupied by 
the species and because they contain essential physical or biological 
features that may require special management considerations or 
protection. The following narratives describe all of the subunits 
proposed as critical habitat in the Verde River Subbasin Unit.
    Upper Verde River Subunit. We are proposing to designate 20,526 
acres (8,307 ha) of critical habitat along 139.8 stream mi (224.9 km) 
of the Verde River, from its confluence with Horseshoe Reservoir, 
upstream to its confluence with Sullivan Lake, in Gila and Yavapai 
Counties, Arizona. The Verde River occurs predominantly on lands 
managed by the U.S. Forest Service on the Prescott, Tonto, and Coconino 
National Forests. Remaining land management and ownership includes the 
Arizona Game and Fish Department, Arizona State Parks, Arizona State 
Trust, Yavapai Apache Tribe, and private land owners. Proposed 
groundwater pumping of the Big Chino Aquifer may adversely affect 
future baseflow in the Verde River, and therefore PCE 1. Development 
along the Verde River has eliminated habitat along portions of the 
Verde River through the Verde Valley. In general, this subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
3 (prey base), but PCE 4 (absence or low level of harmful nonnative 
species) is deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
elimination or reduction of crayfish, bullfrogs, and nonnative, spiny-
rayed fish, as well as ensuring adequate flow is retained in the Verde 
River. Lands along the Verde River included in the Arizona Game and 
Fish Departments' Upper Verde Wildlife Area, The Nature Conservancy's 
Verde Springs Preserve and Verde Valley property, lands owned by the 
Yavapai Apache Tribe, and lands owned by the Salt River Project and 
managed under their Horseshoe-Bartlett and Roosevelt HCPs are being 
considered for exclusion from the final rule for critical habitat under 
section 4(b)(2) of the Act (see Application of Section 4(b)(2) of the 
Act below).
    Oak Creek Subunit. We are proposing to designate 5,533 acres (2,239 
ha) of critical habitat along 38.5 stream mi (62.0 km) of Oak Creek, 
from its confluence with the Verde River south of Cornville, upstream 
to Midgely Bridge at the confluence with Wilson Canyon, in Coconino 
County, Arizona. Also included in this subunit are 149 acres (60 ha) of 
the Arizona Game and Fish Department's Bubbling Ponds and Page Springs 
State Fish Hatcheries, which are adjacent to each other, and occur 
along Oak Creek, upstream of its confluence with Spring Creek. The Oak 
Creek subunit occurs predominately on privately owned lands or lands 
managed by the Coconino National Forest. Remaining lands are managed by 
Arizona Game and Fish Department and Arizona State Parks. This reach of 
lower Oak Creek is largely dominated by crayfish, bullfrogs, and 
nonnative, spiny-rayed fish. This subunit contains sufficient physical 
or biological features, including PCEs 1 (aquatic habitat 
characteristics) and 2 (terrestrial habitat characteristics), but PCEs 
3 (prey base) and 4 (absence or low level of harmful nonnative species) 
are deficient. Special management may be required to maintain or 
develop the physical or biological features, including managing for 
native prey species and eliminating or reducing crayfish, bullfrog, and 
nonnative, spiny-rayed fish populations. Lands along lower Oak Creek 
included within the Arizona Game and Fish Department's Bubbling Ponds 
and Page Springs State Fish Hatcheries are being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Spring Creek Subunit. We are proposing to designate 3,131 acres 
(1,267 ha) of critical habitat along 22.5 stream mi (36.2 km) of Spring 
Creek, from its confluence with the Oak Creek upstream to its origin 
southwest of Buck Ridge, in Yavapai County, Arizona. Spring Creek 
occurs predominately on lands managed by U.S. Forest Service on the 
Tonto and Coconino National Forests. Remaining lands are Arizona State 
Trust and privately owned lands. Spring Creek contains populations of 
lowland leopard frogs and several species of native fish which serve as 
the prey base for northern Mexican gartersnakes. However, crayfish have 
been observed as abundant in this subunit. This subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
3 (prey base), but PCE 4 (absence or low level of harmful nonnative 
species) is deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
elimination or reduction of crayfish.
    The Verde River Subbasin Unit is proposed as critical habitat for 
the northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit; water 
diversions; existing and proposed groundwater pumping potentially 
resulting in drying of habitat; potential for high-intensity wildfires; 
and human development of areas adjacent to proposed critical habitat.
Upper Santa Cruz River Subbasin Unit
    The Upper Santa Cruz River Subbasin Unit is generally located in 
southeastern Arizona, east of Nogales, southeast of Patagonia, and 
southwest of Sierra Vista, in the San Rafael Valley, in Santa Cruz and 
Cochise Counties, Arizona. This unit consists of springs, seeps, 
streams, stock tanks, and terrestrial space (overland areas) in between 
these features within a total of 113,895 acres (46,092 ha) of proposed 
critical habitat in the San Rafael Valley, including portions of Parker 
and Scotia canyons of the Huachuca Mountains, Arizona. For the streams 
within this unit, we are proposing the reach of Parker Canyon that 
includes 5.8 stream mi (9.3 km) from Duquesne Road south of Loop Road, 
upstream to and including Parker Canyon Lake. The reach of Scotia 
Canyon we are proposing as critical habitat includes 3.7 stream mi (5.9 
km) from its confluence with an unnamed drainage at the junction with 
Bodie

[[Page 41565]]

Canyon, upstream to its origin west of the Coronado National Forest-
Fort Huachuca Boundary. The upper Santa Cruz River occurs within the 
San Rafael Valley, flowing south into Mexico. We are proposing 13.8 
stream mi (22.2 km) of the upper Santa Cruz River, from the 
International Border, upstream to its headwaters at the top of Sheep 
Ridge Canyon. The Upper Santa Cruz River Subbasin Unit occurs on lands 
primarily managed by the Coronado National Forest, with remaining land 
management under the Arizona State Parks Department. This unit also 
contains private lands. All identified areas described in this unit 
have records for northern Mexican gartersnakes, and all identified 
areas are considered as being currently within the geographical area 
occupied by the species. Therefore, we are proposing this unit under 
section 3(5)(A)(i) of the Act because it is occupied by the species and 
because it contains sufficient amounts of the essential physical or 
biological features that may require special management considerations 
or protection.
    This unit contains adequate populations of Chiricahua and lowland 
leopard frogs, as well as native fish species in various locations and 
densities, with the former being actively recovered in Scotia Canyon. 
Bullfrogs and nonnative, spiny-rayed fish are also known to occur at 
various densities within this unit, and Parker Canyon Lake is managed 
as a warm-water sport fishery. Crayfish are also likely to occur in 
various locations and densities within this unit. Within this unit, 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics) and 3 (prey base) are generally met, but PCE 4 
(absence or low level of harmful nonnative species) is deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including continuing to promote the recovery or 
expansion of native leopard frogs and fish, and eliminating or reducing 
harmful nonnative species. The San Rafael Ranch is being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
section below).
    The Upper Santa Cruz River Subbasin Unit is proposed as critical 
habitat for the northern Mexican gartersnake because it is occupied at 
the time of listing and contains sufficient physical or biological 
features to support life-history functions essential for the 
conservation of the species. The physical or biological features in 
this unit may require special management consideration due to 
competition with, and predation by, harmful nonnative species that are 
present in this unit and potential effects from future high-intensity 
wildfires.
Redrock Canyon Unit
    We are proposing to designate 1,971 acres (798 ha) of critical 
habitat along 14.0 stream mi (22.5 km) of Redrock Canyon, from its 
confluence with Sonoita Creek, upstream to its origin north of Meadow 
Valley in the Canelo Hills, in Santa Cruz County. Redrock Canyon occurs 
predominately on lands managed by the Coronado National Forest with 
remaining land in private ownership. The area proposed along Redrock 
Canyon is within the area considered occupied by the northern Mexican 
gartersnake. Therefore, we are proposing the areas in this unit under 
section 3(5)(A)(i) of the Act because they are occupied by the species 
and because they contain sufficient amounts of the essential physical 
or biological features that may require special management 
considerations or protection.
    Redrock Canyon supports four species of native fish, and Chiricahua 
leopard frogs and Sonora tiger salamanders have been reported. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of bullfrogs and the prevention 
of potential invasions from nonnative, spiny-rayed fish. Lands within 
The Nature Conservancy's Patagonia-Sonoita Creek Preserve in this unit 
are being considered for exclusion from the final rule for critical 
habitat under section 4(b)(2) of the Act (see Application of Section 
4(b)(2) of the Act below).
    The Redrock Canyon Unit is proposed as critical habitat for the 
northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit.
Buenos Aires National Wildlife Refuge Unit
    The Buenos Aires National Wildlife Refuge Unit is generally located 
in southern Arizona, northwest of Nogales and south of Three Points, in 
Pima County, Arizona. This unit consists of a total of 117,335 acres 
(47,484 ha) of proposed critical habitat, including springs, seeps, 
streams, stock tanks, and terrestrial space in between these features 
within the Buenos Aires National Wildlife Refuge. The Buenos Aires 
National Wildlife Refuge Unit occurs on lands solely managed by the 
U.S. Fish and Wildlife Service. This unit is considered as being 
currently within the geographical area occupied by the species. 
Therefore, we are proposing this unit under section 3(5)(A)(i) of the 
Act because it is occupied by the species and because it contains 
sufficient amounts of the essential physical or biological features 
that may require special management considerations or protection.
    This unit has been a focal point for the recovery of Chiricahua 
leopard frogs, providing prey for the northern Mexican gartersnake in a 
core area of stock tanks in the central region of the Refuge. 
Chiricahua leopard frogs also likely disperse from this area into other 
areas within the Refuge. Bullfrogs and crayfish remain a concern in 
Arivaca Cienega and Arivaca Creek. While not part of this unit, Arivaca 
Lake is operated as a warm-water sport fishery, and nonnative, spiny-
rayed fish may be washed down and persist below the lake dam after 
overflow events. Within this unit, PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 3 (prey 
base) are generally present, but PCE 4 (absence or low level of harmful 
nonnative species) is deficient. Special management may be required to 
maintain or develop the physical or biological features, including the 
elimination or reduction of crayfish, bullfrogs, and nonnative, spiny-
rayed fish, as well as the prevention of a bullfrog invasion in 
Chiricahua leopard frog recovery core areas.
    The Buenos Aires National Wildlife Refuge Unit is proposed as 
critical habitat for the northern Mexican gartersnake because it is 
occupied at the time of listing and contains sufficient physical or 
biological features to support life-history functions essential for the 
conservation of the species. The physical or biological features in 
this unit may require special management consideration due to 
competition with, and predation by, harmful nonnative species that are 
present in this unit.
Cienega Creek Subbasin Unit
    The Cienega Creek Subbasin Unit is generally located in southern 
Arizona, east of the Santa Rita Mountains, north

[[Page 41566]]

of the Canelo Hills, and west of the Whetstone Mountains, in Pima and 
Santa Cruz Counties. This unit consists of springs, seeps, streams, 
stock tanks, and terrestrial space in between these features within a 
total of 50,393 acres (20,393 ha) of proposed critical habitat in the 
Las Cienegas National Conservation Area and Cienega Creek Natural 
Preserve. Also included in this unit is 7.1 stream mi (11.4 km) of 
Cienega Creek that occur outside of these specific ownership areas. The 
Cienega Creek Subbasin Unit occurs on lands primarily managed by the 
U.S. Bureau of Land Management and the Arizona State Land Department, 
with remaining lands under private ownership. All identified areas are 
considered as being within the geographical area currently occupied by 
the species. We are proposing the areas in this unit under section 
3(5)(A)(i) of the Act because they are occupied by the species and 
because they contain essential physical or biological features that may 
require special management considerations or protection. The following 
narratives describe all of the subunits proposed as critical habitat in 
the Cienega Creek Subbasin Unit.
    Cienega Creek Subunit. We are proposing to designate 1,113 acres 
(450 ha) of critical habitat along 7.1 stream mi (11.4 km) of Cienega 
Creek, from the northern boundary of the Las Cienegas National 
Conservation Area to the southern boundary of Cienega Creek Natural 
Preserve in Pima County, Arizona. The Cienega Creek Subunit occurs on 
lands managed by the Arizona State Land Department in addition to a 
small amount of private land. Native fish and both Chiricahua and 
lowland leopard frog populations provide prey for northern Mexican 
gartersnakes, and recent, ongoing bullfrog eradication in the area 
reduces the threat of bullfrogs within this subunit. This subunit 
contains sufficient physical or biological features, including all 
PCEs. However, special management may be required to maintain or 
develop the physical or biological features, including preventing the 
invasion or reinvasion of bullfrogs.
    Las Cienegas National Conservation Area Subunit. We are proposing 
to designate critical habitat for a total of 45,020 acres (18,219 ha) 
of springs, seeps, streams, stock tanks, and terrestrial space in 
between these features within the Las Cienegas National Conservation 
Area in Pima County, including portions of Cienega Creek and Empire 
Gulch that occur within the Las Cienegas National Conservation Area. 
The Las Cienegas National Conservation Area is managed by the U.S. 
Bureau of Land Management, although it includes some Arizona State 
Trust Lands. Native fish and both Chiricahua and lowland leopard frog 
populations provide prey for northern Mexican gartersnakes, and recent, 
ongoing bullfrog eradication in the area reduces the threat of 
bullfrogs within this subunit. This subunit contains sufficient 
physical or biological features, including all PCEs. However, special 
management may be required to maintain or develop the physical or 
biological features, including preventing the invasion or reinvasion of 
bullfrogs.
    Cienega Creek Natural Preserve Subunit. We are proposing to 
designate critical habitat for a total of 4,260 acres (1,724 ha) of 
springs, seeps, streams, stock tanks, and terrestrial space in between 
these features within the Cienega Creek Natural Preserve in Pima 
County, Arizona, including the reach of Cienega Creek that occurs 
within the Cienega Creek Natural Preserve. The Cienega Creek Natural 
Preserve is owned and managed by Pima County. Native fish and lowland 
leopard frog populations provide prey for northern Mexican 
gartersnakes, and recent, ongoing bullfrog eradication in the area 
reduces the threat of bullfrogs within this subunit. This subunit 
contains sufficient physical or biological features, including all 
PCEs. However, special management may be required to maintain or 
develop the physical or biological features, including preventing the 
invasion or reinvasion of bullfrogs. This subunit is being considered 
for exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    The Cienega Creek Subbasin Unit is proposed as critical habitat for 
the northern Mexican gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to ongoing and regional threat of 
bullfrogs.
San Pedro River Subbasin Unit
    The San Pedro River Subbasin Unit is generally located in 
southeastern Arizona, east of Sierra Vista, Tucson, and Florence and 
west Douglas, Wilcox, and Safford, in Cochise, Pima, and Pinal 
Counties. This unit consists of a total of 23,690 acres (9,587 ha) 
along 165 stream mi (266 km) of proposed critical habitat along the San 
Pedro River and Bear Creek. Land ownership or land management within 
this unit consists of lands managed by the U.S. Bureau of Land 
Management, Coronado National Forest, Arizona State Land Department, 
San Carlos Apache Tribe, and privately owned lands. All identified 
areas described in the San Pedro River Subbasin Unit have records for 
northern Mexican gartersnakes, and all identified areas are considered 
as being currently within the geographical area occupied by the 
species. Therefore, we are proposing the areas in this unit under 
section 3(5)(A)(i) of the Act because they are occupied by the species 
and because they contain sufficient amounts of the essential physical 
or biological features that may require special management 
considerations or protection. The following narratives describe all of 
the subunits proposed as critical habitat in the San Pedro River 
Subbasin Unit.
    San Pedro River Subunit. We are proposing to designate 22,669 acres 
(9,174 ha) of critical habitat along 158.4 stream mi (254.9 km) of the 
San Pedro River from its confluence with the Gila River at Winkelman, 
upstream to the International Border, in Cochise, Pima, and Pinal 
Counties, Arizona. The San Pedro River Subunit occurs predominately on 
privately owned lands, with remaining lands managed by the U.S. Bureau 
of Land Management. Native fish and lowland leopard frogs occur 
throughout the San Pedro River and provide a prey base for northern 
Mexican gartersnakes, with prey population densities increasing in the 
downstream direction. Crayfish, bullfrogs, and nonnative, spiny-rayed 
fish occur predominately upstream of the Interstate 10 crossing. In 
general, this subunit contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics), 2 
(terrestrial habitat characteristics), and 3 (prey base), but PCE 4 
(absence or low level of harmful nonnative species) is deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including the elimination or reduction of 
harmful nonnative species. Lands in this subunit that are owned or 
under conservation easement with The Nature Conservancy as conservation 
preserves, lands owned by the Salt River Project and managed under 
their Horseshoe-Bartlett and Roosevelt HCPs, as well as lands owned by 
the San Carlos Apache Tribe, are being considered for exclusion from 
the final rule for critical habitat under section 4(b)(2) of the Act 
(see Application of Section 4(b)(2) of the Act below).
    Bear Canyon Creek Subunit. We are proposing to designate 1,022 
acres (414 ha) of critical habitat along 7.1 stream mi (11.3 km) of 
Bear Canyon Creek, from the International Border, upstream

[[Page 41567]]

to its origin south of Granite Peak in the Huachuca Mountains, in 
Cochise County, Arizona. The Bear Canyon Creek Subunit occurs 
predominately on lands managed by the Coronado National Forest with 
remaining land in private ownership. Native fish comprise the fishery 
of Bear Canyon Creek, and GIS analysis suggests that native leopard 
frogs may also occur in limited density. Crayfish are also present. 
This subunit contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics), 2 (terrestrial 
habitat characteristics), and 3 (prey base), but PCE 4 (absence or low 
level of harmful nonnative species) is deficient. Special management 
may be required to maintain or develop the physical or biological 
features, including the elimination or reduction of crayfish and the 
establishment of secure leopard frog populations.
    The San Pedro River Subbasin Unit is proposed as critical habitat 
for the northern Mexican gartersnake because it is occupied at the time 
of listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit.
Babocomari River Subbasin Unit
    The Babocomari River Subbasin Unit is generally located in 
southeastern Arizona, east of Santa Rita Mountains, north of the Canelo 
Hills and Huachuca Mountains, south of the Whetstone Mountains, and 
west of the San Pedro River, in Santa Cruz and Cochise Counties. This 
unit consists of springs, seeps, streams, stock tanks, and terrestrial 
space in between these features within a total of 14,334 acres (5,801 
ha) of proposed critical habitat in the Canelo Hills Cienega Preserve 
and Appleton-Whittell Research Ranch as well as along a total of 45 
stream mi (72 km) of portions of the Babocomari River, Post Canyon, 
O'Donnell Canyon, and Turkey Creek. Land ownership or management within 
this unit consists of lands managed by the U.S. Bureau of Land 
Management, Coronado National Forest, Arizona State Land Department, 
and privately owned lands. All identified areas described in the 
Babocomari River Subbasin Unit have records for northern Mexican 
gartersnakes, and all identified areas are considered as being 
currently within the geographical area occupied by the species. 
Therefore, we are proposing the areas in this unit under section 
3(5)(A)(i) of the Act because they are occupied by the species and 
because they contain sufficient amounts of the essential physical or 
biological features that may require special management considerations 
or protection. The following narratives describe all of the subunits 
proposed as critical habitat in the Babocomari River Subbasin Unit.
    Babocomari River/Cienega Subunit. We are proposing to designate 
3,454 acres (1,398 ha) of critical habitat along approximately 24.4 
stream mi (39.2 km) of the Babocomari River from its confluence with 
the San Pedro River northwest of Fairbank, upstream to its confluence 
with an unnamed drainage south of the railroad and southeast of Elgin, 
in Cochise and Santa Cruz Counties, Arizona. The Babocomari River 
Subunit occurs predominately on privately owned lands, with remaining 
lands managed by the U.S. Bureau of Land Management. Crayfish, 
bullfrogs, and nonnative, spiny-rayed fish all occur within this 
subunit at various densities, reducing the likelihood of maintaining a 
suitable native prey base for northern Mexican gartersnakes. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics) and 2 (terrestrial habitat 
characteristics), but PCEs 3 (prey base) and 4 (absence or low level of 
harmful nonnative species) are deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of harmful nonnative species and 
reestablishment of native prey species.
    Post Canyon Subunit. We are proposing to designate 795 acres (322 
ha) of critical habitat along approximately 5.7 stream mi (9.1 km) of 
Post Canyon, from the western boundary of the Appleton-Whittell 
Research Ranch, upstream to Post Well at the top of Post Canyon, in 
Santa Cruz County, Arizona. The Post Canyon Subunit occurs largely on 
privately owned lands as well as those managed by the Coronado National 
Forest.
    Lowland leopard frogs and, perhaps, Chiricahua leopard frogs 
provide prey for northern Mexican gartersnakes in Post Canyon. Native 
fish may also occur due to a connection with nearby habitat that native 
fish are known to occupy. Crayfish occur in Post Canyon, and nonnative, 
spiny-rayed fish, as well as bullfrogs, are known from the vicinity and 
may be present. This subunit contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics), 2 
(terrestrial habitat characteristics), and 3 (prey base), but PCE 4 
(absence or low level of harmful nonnative species) is deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including the elimination or reduction of 
crayfish and the prevention of potential bullfrog and nonnative, spiny-
rayed fish invasions. Lands owned by the Appleton-Whittell Research 
Ranch within this subunit are being considered for exclusion from the 
final rule for critical habitat under section 4(b)(2) of the Act (see 
Application of Section 4(b)(2) of the Act below).
    O'Donnell Canyon Subunit. We are proposing to designate 398 acres 
(161 ha) of critical habitat along approximately 2.5 stream mi (4.0 km) 
of O'Donnell Canyon, between the southern boundary of the Appleton-
Whittell Research Ranch upstream to the northern boundary of the Canelo 
Hills Cienega Preserve, and then from the southern boundary of the 
Canelo Hills Cienega Preserve upstream to its confluence with Pauline 
and Middle canyons, in Santa Cruz County, Arizona. The O'Donnell Canyon 
Subunit occurs predominantly on privately owned lands and those managed 
by the Coronado National Forest. The area proposed along O'Donnell 
Canyon is within the area considered occupied by the northern Mexican 
gartersnake.
    Populations of native fish and Chiricahua leopard frogs provide a 
prey base for northern Mexican gartersnakes in O'Donnell Canyon, but 
crayfish and nonnative, spiny-rayed fish may be present. Bullfrogs 
inhabit the region and present a threat of invasion. This subunit 
contains sufficient physical or biological features, including PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish and nonnative, 
spiny-rayed fish, as well as the prevention of potential bullfrog 
invasions. Lands owned by the Appleton-Whittell Research Ranch and the 
Canelo Hills Cienega Preserve within this subunit are being considered 
for exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Turkey Creek Subunit. We are proposing to designate 1,678 acres 
(679 ha) of critical habitat along approximately 12.0 stream mi (19.4 
km) of Turkey Creek, from its confluence with the Babocomari River, 
upstream to the northern boundary of the Appleton-Whittell Research 
Ranch, and then from

[[Page 41568]]

the southwestern boundary of the Appleton-Whittell Research Ranch to 
its origin at an unnamed pond east of State Highway 83 and south of 
Forest Road 201, in Santa Cruz and Cochise Counties. The Turkey Creek 
Subunit occurs predominantly on privately owned lands and those managed 
by the Coronado National Forest.
    Turkey Creek historically supported two species of native fish, 
which could still remain and supplement possible resident amphibian 
prey sources. One bullfrog was detected in 2004 within Turkey Creek, 
but no crayfish or nonnative, spiny-rayed fish species are thought to 
currently occur there. This subunit contains sufficient physical or 
biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 4 
(absence or low level of harmful nonnative species), but PCE 3 (prey 
base) may be deficient. However, special management may be required to 
maintain or develop the physical or biological features, including 
preventing harmful nonnative species from becoming established and 
reintroducing native fish and leopard frogs into Turkey Creek. Lands 
owned by the Appleton-Whittell Research Ranch within this subunit are 
being considered for exclusion from the final rule for critical habitat 
under section 4(b)(2) of the Act (see Application of Section 4(b)(2) of 
the Act below).
    Appleton-Whittell Research Ranch Subunit. We are proposing to 
designate critical habitat on approximately 7,798 acres (3,156 ha) of 
springs, seeps, streams, stock tanks, and terrestrial space in between 
these features within the Appleton-Whittell Research Ranch, in Santa 
Cruz County, Arizona. Portions of Post Canyon, O'Donnell Canyon, and 
Turkey Creek are included in this subunit. The Appleton-Whittell 
Research Ranch subunit occurs on privately owned lands, as well as 
lands managed by the Bureau of Land Management and Coronado National 
Forest. The management of the Appleton-Whittell Research Ranch is 
overseen by The Audubon Society. Native fish and native leopard frog 
populations occur throughout Ranch and provide prey for northern 
Mexican gartersnakes. However, crayfish, bullfrogs, and nonnative, 
spiny-rayed fish occur regionally and are an ongoing threat to northern 
Mexican gartersnakes in this area. This subunit contains sufficient 
physical or biological features, including all PCEs. However, special 
management may be required to maintain or develop the physical or 
biological features, including preventing the invasion of harmful 
nonnative species. Private lands in this subunit are being considered 
for exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Canelo Hills Cienega Preserve Subunit. We are proposing to 
designate critical habitat on approximately 213 acres (86 ha) of 
springs, seeps, streams, stock tanks, and terrestrial space in between 
these features within the Canelo Hills Cienega Preserve, in Santa Cruz 
County, Arizona. Portions of Post Canyon and O'Donnell Canyon are 
included within this subunit. The Canelo Hills Cienega Preserve 
includes lands owned by The Nature Conservancy, as well as other 
private lands under conservation easements with The Nature Conservancy. 
Native fish and leopard frogs may occur within this subunit. We do not 
have updated information on the status of harmful nonnative species in 
this subunit, but its management likely favors native species within 
the Preserve. Therefore, we conclude that this subunit contains all 
PCEs. However, special management may be required to maintain or 
develop the physical or biological features, including preventing 
harmful nonnative species from becoming established. This subunit is 
being considered for exclusion from the final rule for critical habitat 
under section 4(b)(2) of the Act (see Application of Section 4(b)(2) of 
the Act below).
    The Babocomari River Subbasin Unit is proposed as critical habitat 
for the northern Mexican gartersnake because it is occupied at the time 
of listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit.
San Bernardino National Wildlife Refuge (SBNWR) Unit
    The SBNWR Unit is generally located in extreme southeastern 
Arizona, east of Douglas and west of the New Mexico border, and sharing 
its southern border with Mexico, in Cochise County, Arizona. This unit 
consists of a total of 2,387 acres (966 ha) of springs, seeps, streams, 
stock tanks, and terrestrial space in between these features, including 
the headwaters of the Yaqui River. The U.S. Fish and Wildlife Service 
is the sole land manager within this unit.
    The SBNWR was a historical stronghold for northern Mexican 
gartersnakes, but the species has become rare in current times. 
Therefore, we are proposing this unit under section 3(5)(A)(i) of the 
Act because it is occupied by the species and because it contains 
sufficient amounts of the essential physical or biological features 
that may require special management considerations or protection. The 
SBNWR contains records for five species of native fish as well as 
lowland and Chiricahua leopard frog populations, but the status of the 
latter is uncertain due to the presence of bullfrogs on the refuge. 
This unit contains an adequate amount of physically suitable aquatic 
and terrestrial habitat, with the appropriate characteristics to 
support the northern Mexican gartersnake. Within this unit, PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base) are generally present, but PCE 4 
(absence or low level of harmful nonnative species) is deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including the elimination or reduction of 
bullfrogs.
    The SBNWR Unit is proposed as critical habitat for the northern 
Mexican gartersnake because it is occupied at the time of listing and 
contains sufficient physical or biological features to support life-
history functions essential for the conservation of the species. The 
physical or biological features in this unit may require special 
management consideration due to competition with, and predation by, 
bullfrogs that are present in this unit.

Narrow-Headed Gartersnake

Upper Gila River Subbasin Unit
    The Upper Gila River Subbasin Unit is generally located 
southwestern New Mexico in the Gila Wilderness of the Gila National 
Forest in Catron, Grant, Hidalgo, and Sierra Counties, New Mexico, and 
eastern Arizona in Graham County. This unit consists of a total of 
49,903 acres (20,195 ha) along 359 stream mi (578 km) of proposed 
critical habitat along the mainstem, East, West, and Middle Forks of 
the Gila River, Black Canyon, Diamond Creek, Gilita Creek, Iron Creek, 
Little Creek, and Turkey Creek. Land ownership or land management 
within this unit consists of lands managed by the U.S. Forest Service, 
U.S. Bureau of Land Management, National Park Service, New Mexico 
Department of Game and Fish, State Trust lands, and private ownership. 
All identified areas described in the Upper Gila River Subbasin Unit 
have records since 1980 for narrow-headed gartersnakes, and all

[[Page 41569]]

identified areas are considered as being within the geographical area 
currently occupied by the species. We are proposing the areas in this 
unit under section 3(5)(A)(i) of the Act because they are occupied by 
the species and because they contain essential physical or biological 
features that may require special management considerations or 
protection. The following narratives describe all of the subunits 
proposed as critical habitat in the Upper Gila River Subbasin Unit.
    Gila River Subunit. We are proposing to designate 21,135 acres 
(8,553 ha) of critical habitat along 148.2 stream mi (238.6 km) of the 
Gila River mainstem, from its confluence with the San Francisco River 
in Graham County, Arizona, through Hidalgo county, New Mexico, upstream 
to its confluence with East Fork Gila River and Black Canyon in Catron 
County, New Mexico. The mainstem Gila River Subunit contains primarily 
privately owned lands, as well as lands managed by the Gila National 
Forest, the New Mexico Department of Game and Fish, and the Arizona and 
New Mexico State Land Departments. Several reaches of the Gila River in 
New Mexico have been adversely affected by channelization and 
diversions, which have reduced or eliminated baseflow. As a whole, 
however, this subunit contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics), 2 
(terrestrial habitat characteristics), and 3 (prey base), but PCE 4 
(absence or low level of harmful nonnative species) is deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including the elimination or reduction of 
harmful nonnative species, as well as to maintain adequate base flow in 
the Gila River. Lands within The Nature Conservancy's Gila Riparian 
Preserve in this subunit are being considered for exclusion from the 
final rule for critical habitat under section 4(b)(2) of the Act (see 
Application of Section 4(b)(2) of the Act below).
    East Fork Gila River Subunit. We are proposing to designate 3,579 
acres (1,448 ha) of critical habitat along 27.6 stream mi (44.4 km) of 
the East Fork Gila River, from its confluence with the mainstem Gila 
River in Grant County, New Mexico, upstream to its confluence with 
Beaver Creek and Taylor Creek in Catron County, New Mexico. The East 
Fork Gila River Subunit is primarily managed by the Gila National 
Forest, with additional parcels under private ownership. This subunit 
contains sufficient physical or biological features, including PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish, bullfrogs, and 
nonnative, spiny-rayed fish.
    West Fork Gila River Subunit. We are proposing to designate 5,169 
acres (2,092 ha) of critical habitat along 37.2 stream mi (59.9 km) of 
the West Fork Gila River, from its confluence with the mainstem Gila 
River and East Fork Gila River in Grant County, New Mexico, upstream to 
its origin east of Center Baldy Peak in Catron County, New Mexico. The 
West Fork Gila River Subunit is primarily managed by the Gila National 
Forest with additional parcels under private ownership or managed by 
the National Park Service or the New Mexico Department of Game and 
Fish. Historically, the West Fork Gila River maintained large 
populations of bullfrogs and nonnative, spiny-rayed fish. As a result 
of ash and sediment flows following the 2012 Whitewater-Baldy Complex 
Fire, these harmful nonnative species may have been reduced (bullfrogs) 
or possibly eliminated (spiny-rayed fish). This subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
4 (absence or low level of harmful nonnative species), but PCE 3 (prey 
base) may be deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
preventing the reinvasion of harmful nonnative species and the 
reestablishment of native prey lost as a result of the 2012 Whitewater-
Baldy Complex Fire.
    Middle Fork Gila River Subunit. We are proposing to designate 4,964 
acres (2,009 ha) of critical habitat along 37.0 stream mi (59.5 km) of 
the Middle Fork Gila River, from its confluence with the West Fork Gila 
River in Catron County, New Mexico, upstream to its confluence with 
Gilita Creek and Iron Creek in Catron County, New Mexico. The Middle 
Fork Gila River Subunit is primarily managed by the Gila National 
Forest with additional parcels managed by the New Mexico Department of 
Game and Fish. Historically, the West Fork Gila River maintained large 
populations of bullfrogs and nonnative, spiny-rayed fish. As a result 
of ash and sediment flows following the 2012 Whitewater-Baldy Complex 
Fire, these harmful nonnative species may have been reduced (bullfrogs) 
or possibly eliminated (spiny-rayed fish). This subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
4 (absence or low level of harmful nonnative species), but PCE 3 (prey 
base) may be deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
preventing the reinvasion of harmful nonnative species and the 
reestablishment of native prey lost as a result of the 2012 Whitewater-
Baldy Complex Fire.
    Black Canyon Subunit. We are proposing to designate 3,503 acres 
(1,418 ha) of critical habitat along 25.8 stream mi (41.5 km) of Black 
Canyon, from its confluence with East Fork Gila River in Catron County, 
New Mexico, upstream to its confluence with Gilita Creek and Iron Creek 
in Catron County, New Mexico. Black Canyon is primarily managed by the 
Gila National Forest with additional parcels under private ownership. 
This area contains sufficient physical or biological features, 
including all PCEs. Special management may be required to maintain or 
develop the physical or biological features, including management 
against the invasion of harmful nonnative species.
    Diamond Creek Subunit. We are proposing to designate 3,545 acres 
(1,435 ha) of critical habitat along 25.4 stream mi (40.9 km) of 
Diamond Creek, from its confluence with East Fork Gila River in Catron 
County, New Mexico, upstream to its confluence with the unnamed 
drainage northeast of Turkey Park in Sierra County, New Mexico. The 
Diamond Creek Subunit is primarily managed by the Gila National Forest 
with additional parcels under private ownership. This area contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
3 (prey base), but PCE 4 (absence or low level of harmful nonnative 
species) is deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
elimination or reduction of crayfish and nonnative, spiny-rayed fish.
    Gilita Creek Subunit. We are proposing to designate 1,704 acres 
(690 ha) of critical habitat along 12.1 stream mi (19.5 km) of Gilita 
Creek, from its confluence with Middle Fork Gila River in Catron 
County, New Mexico, upstream to its confluence with the unnamed 
drainage in Turkey Cienega, south of Bear Wallow Lookout Road, in 
Catron County, New Mexico. The Gilita Creek Subunit is managed by the 
Gila

[[Page 41570]]

National Forest. Several improved and unimproved road crossings occur 
along Gilita Creek, which may act as a source of sedimentation to the 
creek. However, this subunit appears to contain sufficient physical or 
biological features, including all PCEs. Special management may be 
required to maintain or develop the physical or biological features, 
including management against the invasion of harmful nonnative species, 
as well as to control erosion and sedimentation issues.
    Iron Creek Subunit. We are proposing to designate 1,731 acres (701 
ha) of critical habitat along 12.4 stream mi (19.9 km) of Iron Creek, 
from its confluence with Middle Fork Gila River in Catron County, New 
Mexico, upstream to its confluence with the unnamed drainage southeast 
of Whitewater Baldy Peak in Catron County, New Mexico. The Iron Creek 
Subunit is managed by the Gila National Forest. This subunit was 
affected by ash and sediment flows resulting from the 2012 Whitewater-
Baldy Complex Fire that have likely reduced the prey base for narrow-
headed gartersnakes. This subunit contains sufficient physical or 
biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 4 
(absence or low level of harmful nonnative species), but PCE 3 (prey 
base) is deficient. Special management may be required to maintain or 
develop the physical or biological features, including management 
against the invasion of harmful nonnative species and the 
reestablishment of a native prey base.
    Little Creek Subunit. We are proposing to designate 2,236 acres 
(905 ha) of critical habitat along 16.8 stream mi (27.0 km) of Little 
Creek, from its confluence with West Fork Gila River in Catron County, 
New Mexico, upstream to the unnamed spring northwest of Granite Peak in 
Catron County, New Mexico. The Little Creek Subunit is primarily 
managed by the Gila National Forest with additional parcels managed by 
the New Mexico Department of Game and Fish. This subunit was affected 
by ash and sediment flows resulting from the 2011 Miller Fire that have 
likely reduced the prey base for narrow-headed gartersnakes. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 4 (absence or low level of harmful nonnative 
species), but PCE 3 (prey base) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of bullfrogs and the 
reestablishment of a native prey base.
    Turkey Creek Subunit. We are proposing to designate 2,338 acres 
(946 ha) of critical habitat along 16.6 stream mi (26.7 km) of Turkey 
Creek, from its confluence with the Gila River mainstem in Grant 
County, New Mexico, upstream to its confluence with the unnamed 
drainage southwest of Granite Peak in Grant County, New Mexico. The 
Turkey Creek Subunit is managed by the Gila National Forest. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including management against the reinvasion of crayfish and bullfrogs.
    The Upper Gila River Subbasin Unit is proposed as critical habitat 
for the narrow-headed gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. Some reaches of the Gila River have been adversely affected by 
channelization and water diversions. There remains the potential for 
the construction of Hooker Dam in the reach of the Gila River above 
Mogollon Creek and below Turkey Creek as part of the Central Arizona 
Project, which would adversely affect both the physical habitat for 
narrow-headed gartersnakes as well as their prey base, but this project 
remains in deferment status. The 2012 Whitewater-Baldy Complex Fire 
adversely affected the aquatic communities in the West and Middle Fork 
of the Gila River, as well as Iron Creek, as a result of excessive ash 
and sediment flows; this is similar to what occurred in Little Creek as 
a result of the 2011 Miller Fire. The physical or biological features 
in this unit may require special management consideration due to 
competition with, and predation by, harmful nonnative species that are 
present in this unit; water diversions; channelization; potential for 
high-intensity wildfires; and human development of areas adjacent to 
proposed critical habitat.
Middle Gila River Subbasin Unit
    The Middle Gila River Mainstem Subbasin Unit is generally located 
within the Mogollon Rim in eastern Arizona (Greenlee and Graham 
Counties), from the upstream end of San Carlos Reservoir to the 
confluence of the San Francisco and Gila rivers in Arizona. This unit 
consists of a total 8,814 acres (3,567 ha) along 63 stream mi (101 km) 
of proposed critical habitat along the Gila River and Eagle Creek. Land 
ownership or land management within this unit consists of federally 
managed lands, tribal lands, and privately owned lands. Federal lands 
include those managed by the U.S. Bureau of Land Management and the 
U.S. Forest Service. Tribal lands include those owned by the San Carlos 
Apache Tribe. All identified areas described in the Middle Gila River 
Subbasin Unit have records for narrow-headed gartersnakes, and all 
identified areas are considered as currently within the geographical 
area occupied by the species. Therefore, we are proposing the areas in 
this unit under section 3(5)(A)(i) of the Act because they are occupied 
by the species and because they contain sufficient amounts of the 
essential physical or biological features that may require special 
management considerations or protection. The following narratives 
describe all of the subunits proposed as critical habitat in the Middle 
Gila River Subbasin Unit.
    Gila River Subunit. We are proposing to designate 432 acres (175 
ha) of critical habitat along 2.8 stream mi (4.5 km) of the Gila River 
mainstem in Arizona, from the upstream end of the San Carlos Reservoir, 
upstream to its confluence with the San Francisco River, in Greenlee 
and Graham Counties. The reach of the Gila River mainstem within this 
subunit is managed by the U.S. Bureau of Land Management. This subunit 
contains sufficient physical or biological features, including PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of harmful nonnative species.
    Eagle Creek Subunit. We are proposing to designate 8,382 acres 
(3,392 ha) of critical habitat along 60.1 stream mi (96.7 km) of Eagle 
Creek, Arizona, from its confluence with the Gila River, upstream to 
its confluence with East Eagle Creek and Dry Prong Creek in Graham 
County. Eagle Creek occurs primarily on privately owned lands, with 
remaining lands managed by the Apache-Sitgreaves National Forest and 
the U.S. Bureau of Land Management, with additional lands owned by the 
San Carlos Apache Tribe. Groundwater pumping and water diversions from 
Eagle Creek for use at

[[Page 41571]]

the Morenci Mine may affect baseflow in Eagle Creek. However, this 
subunit generally contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics), 2 (terrestrial 
habitat characteristics), and 3 (prey base), but PCE 4 (absence or low 
level of harmful nonnative species) is deficient. Special management 
may be required to maintain or develop the physical or biological 
features, including the elimination or reduction of crayfish and 
nonnative, spiny-rayed fish, as well as to maintain adequate base flows 
in Eagle Creek. Lands owned by the San Carlos Apache Tribe are being 
considered for exclusion from the final rule for critical habitat under 
section 4(b)(2) of the Act (see Application of Section 4(b)(2) of the 
Act below).
    The Middle Gila River Subbasin Unit is proposed as critical habitat 
for the narrow-headed gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. Agricultural diversions and groundwater pumping have caused 
declines in the water table, and surface flows in this reach of the 
Gila River. The physical or biological features in this unit may 
require special management consideration due to competition with, and 
predation by, harmful nonnative species that are present in this unit; 
water diversions; groundwater pumping; potential for high-intensity 
wildfires; and human development of areas adjacent to proposed critical 
habitat.
San Francisco River Subbasin Unit
    The San Francisco River Subbasin Unit is generally located in 
eastern Arizona in the vicinity of Clifton (Greenlee County), including 
southwestern New Mexico in the vicinities of Glenwood and Reserve, New 
Mexico (Catron County). This unit consists of a total of 45,075 acres 
(18,241 ha) along 322 stream mi (517 km) of proposed critical habitat 
along the San Francisco mainstem, Blue River, Campbell Blue Creek, Dry 
Blue Creek, South Fork Negrito Creek, Saliz Creek, Tularosa River, and 
Whitewater Creek. Land ownership or land management within this unit 
consists of lands managed by the U.S. Forest Service, U.S. Bureau of 
Land Management, New Mexico Department of Fish and Game, State Trust 
lands, and private ownership. Some identified areas described in the 
San Francisco River Subbasin Unit have records for narrow-headed 
gartersnakes, but all identified areas are considered as being 
currently within the geographical area occupied by the species. 
Therefore, we are proposing the areas in this unit under section 
3(5)(A)(i) of the Act because they are occupied by the species and they 
contain sufficient amounts of the essential physical or biological 
features that may require special management considerations or 
protection. The following narratives describe all of the subunits 
proposed as critical habitat in the San Francisco River Unit.
    San Francisco River Subunit. We are proposing to designate 23,178 
acres (9,380 ha) of critical habitat along 163.3 stream mi (262.7 km) 
of the San Francisco River, from its confluence with the Gila River in 
Greenlee County, Arizona, upstream to its origin northwest of Long 
Canyon in the Noble Mountains in Catron County, New Mexico. The San 
Francisco River Subunit is primarily managed by the Apache-Sitgreaves 
and Gila National Forests, with additional parcels managed by the U.S. 
Bureau of Land Management, the Arizona State Land Department, and under 
private ownership. Water diversions have dewatered sections of the San 
Francisco River in the upper Alma Valley and at Pleasanton, New Mexico. 
The San Francisco River has historically maintained populations of 
bullfrogs, crayfish, and nonnative, spiny-rayed fish at various 
densities along its course. The 2012 Whitewater-Baldy Complex Fire 
burned at both moderate and high severity within the San Francisco 
River Subbasin and has likely resulted in significant flooding with 
excessive ash and sediment loads. These sediment and ash-laden floods 
may have simultaneously reduced populations of harmful nonnative 
species and native prey species for narrow-headed gartersnakes 
downstream of the confluences with affected tributaries. This subunit 
generally contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics) and 2 (terrestrial 
habitat characteristics), but PCEs 3 (prey base) and 4 (absence or low 
level of harmful nonnative species) may be deficient in some reaches. 
Special management may be required to maintain or develop the physical 
or biological features, including preventing the reinvasion of harmful 
nonnative species and reestablishing native prey lost as a result of 
flooding and ash and sediment flows from the 2012 Whitewater-Baldy 
Complex Fire.
    Blue River Subunit. We are proposing to designate 7,432 acres 
(3,007 ha) of critical habitat along 53.4 stream mi (86.0 km) of the 
Blue River, from its confluence with the San Francisco River, upstream 
to its confluence with Campbell Blue Creek and Dry Blue Creek near the 
Arizona-New Mexico State line in Catron County, New Mexico. The Blue 
River Subunit is primarily managed by the Apache-Sitgreaves National 
Forest with additional parcels under private ownership. The Blue River 
has historically maintained populations of crayfish and nonnative, 
spiny-rayed fish at various densities along its course. The 2011 Wallow 
Fire burned within this subbasin, which resulted in significant 
flooding with excessive ash and sediment loads. These sediment and ash-
laden floods may have simultaneously reduced populations of harmful 
nonnative species and native prey species for narrow-headed 
gartersnakes downstream of the confluences with affected tributaries. 
This subunit generally contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics) and 2 
(terrestrial habitat characteristics), but PCEs 3 (prey base) and 4 
(absence or low level of harmful nonnative species) may be deficient in 
some reaches. Special management may be required to maintain or develop 
the physical or biological features, including preventing the 
reinvasion of harmful nonnative species and reestablishing of native 
prey lost as a result of flooding and ash and sediment flows from the 
2011 Wallow Fire.
    Campbell Blue Creek Subunit. We are proposing to designate 3,008 
acres (1,217 ha) of critical habitat along 22.1 stream mi (35.6 km) of 
Campbell Blue Creek, from its confluence with the Blue River and Dry 
Blue Creek, upstream to its origin on Tenney Mountain in Greenlee 
County, Arizona. The Campbell Blue Creek Subunit is primarily managed 
by the Apache-Sitgreaves National Forest with additional parcels under 
private ownership. The Campbell Blue Creek subbasin resides within the 
footprint of the 2011 Wallow Fire, but the exact effects of the fire on 
this subunit are not entirely known at this time. This subunit 
generally contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics), 2 (terrestrial 
habitat characteristics), and 3 (prey base), but PCE 4 (absence or low 
level of harmful nonnative species) is deficient. Special management 
may be required to maintain or develop the physical or biological 
features, including the elimination or reduction of bullfrogs and 
crayfish.
    Dry Blue Creek Subunit. We are proposing to designate 1,320 acres 
(534 ha) of critical habitat along 9.4 stream

[[Page 41572]]

mi (15.2 km) of Dry Blue Creek, from its confluence with Campbell Blue 
Creek and Blue River, upstream to its origin north of Hy Clark Spring 
in Greenlee County, Arizona. The Dry Blue Creek Subunit is managed by 
the Apache-Sitgreaves National Forest. The area proposed along Dry Blue 
Creek is within the area occupied by the narrow-headed gartersnake. The 
Dry Blue Creek subbasin resides within the footprint of the 2011 Wallow 
Fire, but the exact effects of the fire on this subunit are not 
entirely known at this time. This subunit contains sufficient physical 
or biological features, including all PCEs. Special management may be 
required to maintain or develop the physical or biological features, 
including management against the invasion of bullfrogs and nonnative, 
spiny-rayed fish.
    South Fork Negrito Creek Subunit. We are proposing to designate 
1,483 acres (600 ha) of critical habitat along 10.6 stream mi (17.0 km) 
of South Fork Negrito Creek, from its confluence with Negrito Creek and 
North Fork Negrito Creek, upstream to its confluence with unnamed 
drainage south of FR 4313B, in Catron County, New Mexico. The South 
Fork Negrito Creek Subunit is managed by the Gila National Forest with 
additional parcels under private ownership. South Fork Negrito Creek 
may have been affected by the 2012 Whitewater-Baldy Complex Fire, but 
the exact effects of the fire on this subunit are not entirely known at 
this time. This subunit generally contains sufficient physical or 
biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 3 (prey 
base), but PCE 4 (absence or low level of harmful nonnative species) is 
deficient. Special management may be required to maintain or develop 
the physical or biological features, including the elimination or 
reduction of bullfrogs.
    Saliz Creek Subunit. We are proposing to designate 1,099 acres (445 
ha) of critical habitat along 8.2 stream mi (13.1 km) of Saliz Creek, 
from its confluence with the San Francisco River, upstream to its 
origin at an unnamed spring north of Highway Tank in Catron County, New 
Mexico. The Saliz Creek Subunit is managed by the Gila National Forest 
with additional parcels under private ownership. The narrow-headed 
gartersnake prey base in Saliz Creek was significantly affected by the 
2006 Martinez Fire, but has since rebounded, and the creek now supports 
four species of native fish. This subunit contains sufficient physical 
or biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 3 (prey 
base), but PCE 4 (absence or low level of harmful nonnative species) is 
deficient. Special management may be required to maintain or develop 
the physical or biological features, including management against the 
invasion of bullfrogs, crayfish, and nonnative, spiny-rayed fish.
    Tularosa River Subunit. We are proposing to designate 4,728 acres 
(1,913 ha) of critical habitat along 34.8 stream mi (55.9 km) of the 
Tularosa River, from its confluence with the San Francisco River, 
upstream to Tularosa Spring in Catron County, New Mexico. Land 
ownership along the Tularosa River is primarily private, with 
additional parcels managed by the Gila National Forest and the U.S. 
Bureau of Land Management. This subunit contains sufficient physical or 
biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 3 (prey 
base), but PCE 4 (absence or low level of harmful nonnative species) is 
deficient. Special management may be required to maintain or develop 
the physical or biological features, including the elimination or 
reduction of bullfrogs and crayfish.
    Whitewater Creek Subunit. We are proposing to designate 2,829 acres 
(1,145 ha) of critical habitat along 19.8 stream mi (31.9 km) of 
Whitewater Creek, from its confluence with the San Francisco River, 
upstream to its origin south of Whitewater Baldy Peak in Catron County, 
New Mexico. Land along Whitewater Creek is primarily managed by the 
Gila National Forest with additional parcels managed by the New Mexico 
Department of Fish and Game or under private land ownership. The 2012 
Whitewater-Baldy Complex Fire burned at both moderate and high severity 
within the Whitewater Creek Subbasin, which likely resulted in 
significant flooding with excessive ash and sediment loads. These 
sediment and ash-laden floods have likely reduced native prey 
populations for narrow-headed gartersnakes for the short to medium 
term. This subunit generally contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics), 2 
(terrestrial habitat characteristics), and 4 (absence or low level of 
harmful nonnative species), but PCE 3 (prey base) may be deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including preventing the invasion of harmful 
nonnative species and reestablishing native prey lost as a result of 
flooding and ash and sediment flows from the 2012 Whitewater-Baldy 
Complex Fire.
    The San Francisco River Subbasin Unit is proposed as critical 
habitat for the narrow-headed gartersnake because it is occupied at the 
time of listing and contains sufficient physical or biological features 
to support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit; water 
diversions; potential for high-intensity wildfires; and human 
development of areas adjacent to proposed critical habitat.
Upper Salt River Subbasin Unit
    The Upper Salt River Subbasin Unit is generally located along the 
Mogollon Rim in east-central Arizona, and includes portions of Gila, 
Graham, Apache, Navajo, Greenlee, and Coconino Counties. The Upper Salt 
River Subbasin Unit largely includes remote, rural areas, generally 
under the ownership and management of tribal governments, specifically 
the White Mountain Apache and San Carlos Apache Tribes. This unit 
consists of a total of 58,014 acres (23,478 ha) along 406 stream mi 
(654 km) of proposed critical habitat along the Salt River, White 
River, Canyon Creek, Carrizo Creek, Cibecue Creek, Diamond Creek, and 
Black River. Land ownership or land management within this unit 
consists of tribal lands and federally managed lands. Federal lands 
include those managed by the U.S. Forest Service. All identified areas 
described in the Upper Salt River Subbasin Unit have records for 
narrow-headed gartersnakes, and all identified areas are considered as 
currently within the geographical area occupied by the species. 
Therefore, we are proposing the areas in this unit under section 
3(5)(A)(i) of the Act because they are occupied by the species and 
because they contain sufficient amounts of the essential physical or 
biological features that may require special management considerations 
or protection. The following narratives describe all of the subunits 
proposed as critical habitat in the Upper Salt River Subbasin Unit.
    Salt River Subunit. We are proposing to designate 12,877 acres 
(5,211 ha) of critical habitat along 86.3 stream mi (138.8 km) of the 
Salt River, from its intersection with State Highway 288, upstream to 
its confluence with Black and White rivers, northwest of Forks Butte, 
in Gila County, Arizona. The reach of the Salt River within this 
subunit is primarily owned by the

[[Page 41573]]

White Mountain Apache and San Carlos Apache Tribes with additional 
parcels managed by the Tonto National Forest. This subunit contains 
sufficient physical or biological features, including PCEs 1 (aquatic 
habitat characteristics), 2 (terrestrial habitat characteristics), and 
3 (prey base), but PCE 4 (absence or low level of harmful nonnative 
species) is deficient. Special management may be required to maintain 
or develop the physical or biological features, including the 
elimination or reduction of crayfish and nonnative, spiny-rayed fish. 
Lands owned by the White Mountain Apache and San Carlos Apache Tribes 
are being considered for exclusion from the final rule for critical 
habitat under section 4(b)(2) of the Act (see Application of Section 
4(b)(2) of the Act below).
    White River Subunit. We are proposing to designate 2,588 acres 
(1,047 ha) of critical habitat along 18.1 stream mi (29.1 km) of the 
White River from its confluence with the Salt and Black rivers, 
upstream to its confluence with its own East and North Forks. The White 
River Subunit occurs in Gila and Navajo Counties, Arizona. The White 
River drainage is solely owned by the White Mountain Apache Tribe. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of nonnative, spiny-rayed fish 
and possibly crayfish or bullfrogs. This subunit is being considered 
for exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Canyon Creek Subunit. We are proposing to designate 7,346 acres 
(2,973 ha) of critical habitat along 52.8 stream mi (85.0 km) of Canyon 
Creek, from its confluence with the Salt River northwest of Canyon 
Creek Butte, upstream to its origin southwest of Forest Lakes, south of 
Rim Road, in Coconino, Gila, and Navajo Counties, Arizona. Canyon Creek 
is primarily owned by the White Mountain Apache Tribe with additional 
parcels under management by the Apache-Sitgreaves and Tonto National 
Forests. The area proposed along Canyon Creek is within the area 
occupied by the narrow-headed gartersnake. This subunit contains 
sufficient physical or biological features, including all PCEs. Special 
management may be required to maintain or develop the physical or 
biological features, including preventing the invasion of harmful 
nonnative species. Lands owned by the White Mountain Apache Tribe are 
being considered for exclusion from the final rule for critical habitat 
under section 4(b)(2) of the Act (see Application of Section 4(b)(2) of 
the Act below).
    Carrizo Creek Subunit. We are proposing to designate 9,033 acres 
(3,656 ha) of critical habitat along 64.3 stream mi (103.5 km) of 
Carrizo Creek, from its confluence with the Salt River, upstream to its 
origin north of Carrizo Ridge, north of the White Mountain Apache 
Indian Reservation, in Gila and Navajo Counties, Arizona. Carrizo Creek 
is primarily owned by the White Mountain Apache Tribe with additional 
parcels under Apache-Sitgreaves National Forest management. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) may be deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of harmful nonnative species. 
Lands owned by the White Mountain Apache Tribe are being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Cibecue Creek Subunit. We are proposing to designate 6,669 acres 
(2,699 ha) of critical habitat along 48.1 stream mi (77.3 km) of 
Cibecue Creek, from its confluence with the Salt River west of Coyote 
Canyon, upstream to its origin north of Gatewood Canyon on the White 
Mountain Apache Indian Reservation, in Gila and Navajo Counties, 
Arizona. Cibecue Creek is solely owned by the White Mountain Apache 
Tribe. This subunit contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics), 2 
(terrestrial habitat characteristics), and 3 (prey base), but PCE 4 
(absence or low level of harmful nonnative species) may be deficient. 
Special management may be required to maintain or develop the physical 
or biological features, including the elimination or reduction of 
harmful nonnative species. This subunit is being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act (see Application of Section 4(b)(2) of the Act 
below).
    Diamond Creek Subunit. We are proposing to designate 3,117 acres 
(1,261 ha) of critical habitat along 22.2 stream mi (35.7 km) of 
Diamond Creek, from its confluence with the White River, upstream to 
its origin northwest of Diamond Butte in White Mountains, in Apache and 
Navajo Counties, Arizona. Diamond Creek is solely owned by the White 
Mountain Apache Tribe. This subunit contains sufficient physical or 
biological features, including PCEs 1 (aquatic habitat 
characteristics), 2 (terrestrial habitat characteristics), and 3 (prey 
base), but PCE 4 (absence or low level of harmful nonnative species) 
may be deficient. Special management may be required to maintain or 
develop the physical or biological features, including the elimination 
or reduction of harmful nonnative species. This subunit is being 
considered for exclusion from the final rule for critical habitat under 
section 4(b)(2) of the Act (see Application of Section 4(b)(2) of the 
Act below).
    Black River Subunit. We are proposing to designate 16,384 acres 
(6,630 ha) of critical habitat along 114.4 stream mi (184.0 km) of the 
Black River from its confluence with the Salt and White rivers, 
upstream to its confluence with its own East and West Forks. The Black 
River Subunit occurs in Apache, Gila, Graham and Greenlee Counties, 
Arizona. Areas along the Black River are primarily owned by the White 
Mountain Apache and San Carlos Apache Tribes, with additional parcels 
managed by the Apache-Sitgreaves National Forest. Water in the Black 
River is diverted for use at the Morenci Mine, which may affect 
baseflow. This subunit contains sufficient physical or biological 
features, including PCEs 1 (aquatic habitat characteristics) and 2 
(terrestrial habitat characteristics), but PCEs 3 (prey base) and 4 
(absence or low level of harmful nonnative species) are deficient. The 
native fish prey base may be depressed in the short to medium term as a 
result of the 2011 Wallow Fire. Special management may be required to 
maintain or develop the physical or biological features, including the 
elimination or reduction of crayfish and, possibly, nonnative, spiny-
rayed fish, as well as to maintain adequate base flows in the Black 
River. Lands owned by the White Mountain Apache and San Carlos Apache 
Tribes are being considered for exclusion from the final rule for 
critical habitat under section 4(b)(2) of the Act (see Application of 
Section 4(b)(2) of the Act below).
    The Upper Salt River Subbasin Unit is proposed as critical habitat 
for the narrow-headed gartersnake because it is occupied at the time of 
listing and largely contains sufficient physical or biological features 
to support life-history functions essential for the

[[Page 41574]]

conservation of the species. However, the 2011 Wallow Fire adversely 
affected a large proportion of the Black River drainage, and subsequent 
ash and sediment flows have likely resulted in a depressed fish 
community, which could stress resident narrow-headed gartersnake 
populations in the short to medium term. The physical or biological 
features in this unit may require special management consideration due 
to competition with, and predation by, harmful nonnative species that 
are present in this unit; water diversions; potential for high-
intensity wildfires; and human development of areas adjacent to 
proposed critical habitat.
Tonto Creek Subbasin Unit
    The Tonto Creek Subbasin Unit is generally located southeast of 
Payson, Arizona, and northeast of the Phoenix metropolitan area, in 
Gila County. This unit consists of a total of 12,795 acres (5,178 ha) 
along 91 stream mi (146 km) of proposed critical habitat along Haigler 
Creek, Houston Creek, and Tonto Creek. Land ownership or land 
management within this unit consists of lands managed by the Tonto 
National Forest and privately owned lands. All identified areas are 
considered as being within the geographical area currently occupied by 
the species. We are proposing the areas in this unit under section 
3(5)(A)(i) of the Act because they are occupied by the species and 
because they contain essential physical or biological features that may 
require special management considerations or protection. The following 
narratives describe all of the subunits proposed as critical habitat in 
the Tonto Creek Subbasin Unit.
    Haigler Creek Subunit. We are proposing to designate 3,037 acres 
(1,229 ha) of critical habitat along 21.8 stream mi (35.2 km) of 
Haigler Creek, from its confluence with Tonto Creek upstream to its 
origin at east end of Naeglin Canyon, west of Cherry Creek, in Gila 
County, Arizona. Haigler Creek occurs predominately on lands managed by 
the Tonto National Forest. The remaining land ownership is private. 
This subunit contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics), 2 (terrestrial 
habitat characteristics), and 3 (prey base), but PCE 4 (absence or low 
level of harmful nonnative species) is deficient. Special management 
may be required to maintain or develop the physical or biological 
features, including the elimination or reduction of crayfish.
    Houston Creek Subunit. We are proposing to designate 2,046 acres 
(828 ha) of critical habitat along 14.7 stream mi (23.7 km) of Houston 
Creek, from its confluence with Tonto Creek upstream to its origin 
below Walnut Flat north of the town of Star Valley, in Gila County, 
Arizona. Houston Creek occurs predominately on lands managed by the 
Tonto National Forest. The remaining land ownership is private. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish and nonnative, 
spiny-rayed fish.
    Tonto Creek Subunit. We are proposing to designate 7,712 acres 
(3,121 ha) of critical habitat along 54.1 stream mi (87.0 km) of Tonto 
Creek, from its confluence with an unnamed tributary northeast of 
Punkin Center upstream to its origin northeast of Tonto Spring, south 
of Rim Road, in Gila County, Arizona. Tonto Creek occurs predominately 
on lands managed by the Tonto National Forest. The remaining 
landownership is private. Some reaches along Tonto Creek experience 
seasonal drying as a result of regional groundwater pumping, while 
others are affected by diversions or existing or planned flood control 
projects. Development along private reaches of Tonto Creek may also 
affect terrestrial characteristics of narrow-headed gartersnake 
habitat. Mercury has been detected in fish samples within Tonto Creek, 
and further research is necessary to determine if mercury is 
bioaccumulating in the resident food chain. In general, this subunit 
contains sufficient physical or biological features, including PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish, bullfrogs, and 
nonnative, spiny-rayed fish, as well as to improve base flows.
    The Tonto Creek Subbasin Unit is proposed as critical habitat for 
the narrow-headed gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. The physical or biological features in this unit may require 
special management consideration due to competition with, and predation 
by, harmful nonnative species that are present in this unit; water 
diversions; flood-control projects; potential for high-intensity 
wildfires; and development of areas adjacent to or within proposed 
critical habitat.
Verde River Subbasin Unit
    The Verde River Subbasin Unit is generally located southwest of 
Paulden, Arizona, and northwest of Payson, Arizona, in Coconino, Gila, 
and Yavapai Counties. This unit consists of a total of 35,586 acres 
(14,401 ha) along approximately 248 stream mi (399 km) of proposed 
critical habitat along the Verde River and its tributaries, including 
Oak Creek, West Fork Oak Creek, and the East Verde River. Lands within 
this unit consist of federally managed lands, State Trust lands and 
other State-managed lands, tribal lands, and privately owned lands. All 
identified areas are considered as being within the geographical area 
currently occupied by the species. We are proposing the areas in this 
unit under section 3(5)(A)(i) of the Act because they are occupied by 
the species and because they contain essential physical or biological 
features that may require special management considerations or 
protection. The following narratives describe all of the subunits 
proposed as critical habitat in the Verde River Subbasin Unit.
    Verde River Subunit. We are proposing to designate 18,721 acres 
(7,576 ha) of critical habitat along 127.5 stream mi (205.2 km) of the 
Verde River, from its confluence with Red Creek southwest of Wet Bottom 
Mesa, upstream to its confluence with Sullivan Lake, in Gila and 
Yavapai Counties, Arizona. The Verde River occurs predominantly on 
lands managed by the U.S. Forest Service on the Prescott, Tonto, and 
Coconino National Forests. Remaining land management and ownership 
includes the Arizona Game and Fish Department, Arizona State Parks, 
Arizona State Trust, Yavapai Apache Tribe, and private land owners. 
Proposed groundwater pumping of the Big Chino Aquifer may adversely 
affect future baseflow in the Verde River, and therefore PCE 1. 
Development along the Verde River has eliminated habitat along portions 
of the Verde River through the Verde Valley. In general, this subunit 
contains sufficient physical or biological features, including PCEs 1 
(aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be

[[Page 41575]]

required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish, nonnative, spiny-
rayed fish, and bullfrogs, as well as ensure adequate flow is retained 
in the Verde River. Lands along the Verde River mainstem included in 
the Arizona Game and Fish Departments' Upper Verde Wildlife Area, lands 
owned by the Yavapai Apache Tribe, the Nature Conservancy's Verde 
Springs Preserve, as well as those owned by the Salt River Project and 
addressed within their Horseshoe-Bartlett and Roosevelt Lake Habitat 
Conservation Plans (HCP) are being considered for exclusion from the 
final rule for critical habitat under section 4(b)(2) of the Act (see 
Application of Section 4(b)(2) of the Act below).
    Oak Creek Subunit. We are proposing to designate 7,369 acres (2,982 
ha) of critical habitat along 51.3 stream mi (82.5 km) of Oak Creek, 
from its confluence with the Verde River upstream to its confluence 
with Sterling Canyon, in Yavapai and Coconino Counties, Arizona. Above 
Sterling Canyon, flows are insufficient to maintain aquatic habitat and 
prey species. Oak Creek occurs predominately on lands managed by 
Coconino National Forest and privately owned lands. Remaining lands are 
managed by Arizona Game and Fish Department and Arizona State Parks. 
This subunit contains sufficient physical or biological features, 
including PCEs 1 (aquatic habitat characteristics), 2 (terrestrial 
habitat characteristics), and 3 (prey base), but PCE 4 (absence or low 
level of harmful nonnative species) is deficient downstream of Midgely 
Bridge to the confluence with the Verde River. Special management may 
be required to maintain or develop the physical or biological features, 
including encouragement of native prey base and the elimination or 
reduction of crayfish, nonnative, spiny-rayed fish, and bullfrogs 
downstream of Midgely Bridge.
    West Fork Oak Creek Subunit. We are proposing to designate 2,137 
acres (865 ha) of critical habitat along 16.1 stream mi (25.9 km) of 
West Fork Oak Creek, from its confluence with the Oak Creek upstream to 
its origin southeast of Hog Hill, in Coconino County, Arizona. The West 
Fork of Oak Creek is managed by the Coconino National Forest. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of harmful nonnative species.
    East Verde River Subunit. We are proposing to designate 7,360 acres 
(2,978 ha) of critical habitat along 53.3 stream mi (85.8 km) of East 
Verde River, from the confluence with the Verde River upstream to its 
origin south of Rim Road along the Mogollon Rim, in Gila County, 
Arizona. East Verde River occurs predominantly on lands managed by the 
Tonto National Forest, with remaining lands privately owned. This 
subunit contains sufficient physical or biological features, including 
PCEs 1 (aquatic habitat characteristics), 2 (terrestrial habitat 
characteristics), and 3 (prey base), but PCE 4 (absence or low level of 
harmful nonnative species) is deficient. Special management may be 
required to maintain or develop the physical or biological features, 
including the elimination or reduction of crayfish and nonnative, 
spiny-rayed fish.
    The Verde River Subbasin Unit is proposed as critical habitat for 
the narrow-headed gartersnake because it is occupied at the time of 
listing and contains sufficient physical or biological features to 
support life-history functions essential for the conservation of the 
species. Increasing demands for surface water allocations present a 
potential threat to baseflow in the East Verde River. The physical or 
biological features in this unit may require special management 
consideration due to competition with, and predation by, harmful 
nonnative species that are present in this unit; water diversions; 
existing and proposed groundwater pumping potentially resulting in 
drying of habitat; potential for high-intensity wildfires; and human 
development of areas adjacent to proposed critical habitat.

Effects of Critical Habitat Designation

Section 7 Consultation

    Section 7(a)(2) of the Act requires Federal agencies, including the 
Service, to ensure that any action they fund, authorize, or carry out 
is not likely to jeopardize the continued existence of any endangered 
species or threatened species or result in the destruction or adverse 
modification of designated critical habitat of such species. In 
addition, section 7(a)(4) of the Act requires Federal agencies to 
confer with the Service on any agency action which is likely to 
jeopardize the continued existence of any species proposed to be listed 
under the Act or result in the destruction or adverse modification of 
proposed critical habitat.
    Decisions by the 5th and 9th Circuit Courts of Appeals have 
invalidated our regulatory definition of ``destruction or adverse 
modification'' (50 CFR 402.02) (see Gifford Pinchot Task Force v. U.S. 
Fish and Wildlife Service, 378 F. 3d 1059 (9th Cir. 2004) and Sierra 
Club v. U.S. Fish and Wildlife Service et al., 245 F.3d 434, 442 (5th 
Cir. 2001)), and we do not rely on this regulatory definition when 
analyzing whether an action is likely to destroy or adversely modify 
critical habitat. Under the statutory provisions of the Act, we 
determine destruction or adverse modification on the basis of whether, 
with implementation of the proposed Federal action, the affected 
critical habitat would continue to serve its intended conservation role 
for the species.
    If a Federal action may affect a listed species or its critical 
habitat, the responsible Federal agency (action agency) must enter into 
consultation with us. In addition to actions that occur on Federal 
lands, other examples of actions that are subject to the section 7 
consultation process are actions on State, Tribal, local, or private 
lands that require a Federal permit (such as a permit from the U.S. 
Army Corps of Engineers under section 404 of the Clean Water Act (33 
U.S.C. 1251 et seq.) or a permit from the Service under section 10 of 
the Act), or that involve some other Federal action (such as funding 
from the Federal Highway Administration, Federal Aviation 
Administration, or the Federal Emergency Management Agency). Federal 
actions not affecting listed species or critical habitat, and actions 
on State, Tribal, local, or private lands that are not federally-funded 
or authorized, do not require section 7 consultation.
    As a result of section 7 consultation, we document compliance with 
the requirements of section 7(a)(2) through our issuance of:
    (1) A concurrence letter for Federal actions that may affect, but 
are not likely to adversely affect, listed species or critical habitat; 
or
    (2) A biological opinion for Federal actions that may affect, or 
are likely to adversely affect, listed species or critical habitat.
    When we issue a biological opinion concluding that a project is 
likely to jeopardize the continued existence of a listed species and/or 
destroy or adversely modify critical habitat, we provide reasonable and 
prudent alternatives to the project, if any are identifiable, that 
would avoid the likelihood of jeopardy and/or

[[Page 41576]]

destruction or adverse modification of critical habitat. We define 
``reasonable and prudent alternatives'' (at 50 CFR 402.02) as 
alternative actions identified during consultation that:
    (1) Can be implemented in a manner consistent with the intended 
purpose of the action,
    (2) Can be implemented consistent with the scope of the Federal 
agency's legal authority and jurisdiction,
    (3) Are economically and technologically feasible, and
    (4) Would, in the Director's opinion, avoid the likelihood of 
jeopardizing the continued existence of the listed species and/or avoid 
the likelihood of destroying or adversely modifying critical habitat.
    Reasonable and prudent alternatives can vary from slight project 
modifications to extensive redesign or relocation of the project. Costs 
associated with implementing a reasonable and prudent alternative are 
similarly variable.
    Regulations at 50 CFR 402.16 require Federal agencies to reinitiate 
consultation on previously reviewed actions in instances where we have 
listed a new species or subsequently designated critical habitat that 
may be affected by the action, and the Federal agency has retained 
discretionary involvement or control over the action (or the agency's 
discretionary involvement or control is authorized by law). 
Consequently, Federal agencies sometimes may need to request 
reinitiation of consultation with us on actions for which formal 
consultation has been completed, if those actions with discretionary 
involvement or control may affect subsequently listed species or 
designated critical habitat.

Application of the ``Adverse Modification'' Standard

    The key factor related to the adverse modification determination is 
whether, with implementation of the proposed Federal action, the 
affected critical habitat would continue to serve its intended 
conservation role for the species. In this case, those activities that 
may destroy or adversely modify critical habitat are those that alter 
the physical or biological features to an extent that appreciably 
reduces the conservation value of critical habitat for the northern 
Mexican and narrow-headed gartersnakes. As discussed above, the role of 
critical habitat is to support life-history needs of the species and 
provide for the conservation of the species.
    Section 4(b)(8) of the Act requires us to briefly evaluate and 
describe, in any proposed or final regulation that designates critical 
habitat, activities involving a Federal action that may destroy or 
adversely modify such habitat, or that may be affected by such 
designation.
    Activities that may affect critical habitat, when carried out, 
funded, or authorized by a Federal agency, should result in section 7 
consultation related to effects to the northern Mexican or narrow-
headed gartersnakes. These activities include, but are not limited to:
    (1) Actions that would alter the amount, timing, or frequency of 
flow within a stream or the quantity of available water within wetland 
habitat such that the prey base for either gartersnake species, or the 
gartersnakes themselves, are appreciably diminished or threatened with 
extirpation. Such activities could include, but are not limited to: 
Water diversions; channelization; construction of any barriers or 
impediments within the active river channel; removal of flows in excess 
of those allotted under a given water right; construction of permanent 
or temporary diversion structures; groundwater pumping within aquifers 
associated with the river; or dewatering of isolated within-channel 
pools or stock tanks. These activities could result in the reduction of 
the distribution or abundance of important gartersnake prey species, as 
well as reduce the distribution and amount of suitable physical habitat 
on a regional landscape for the gartersnakes themselves.
    (2) Actions that would significantly increase sediment deposition 
or scouring within the stream channel or pond that is habitat for the 
northern Mexican or narrow-headed gartersnake, or one or more of their 
prey species within the range of either gartersnake species. Such 
activities could include, but are not limited to: Excessive 
sedimentation from livestock overgrazing; road construction; commercial 
or urban development; channel alteration; timber harvest; prescribed 
fires or wildfire suppression; off-road vehicle or recreational use; 
and other alterations of watersheds and floodplains. These activities 
could adversely affect the potential for gartersnake prey species to 
survive or breed. They may also reduce the likelihood that their prey 
species, leopard frogs for example, could move among subpopulations in 
a functioning metapopulation. This would, in turn, decrease the 
viability of metapopulations and their component local populations of 
prey species.
    (3) Actions that would alter water chemistry beyond the tolerance 
limits of a gartersnake prey base. Such activities could include, but 
are not limited to: Release of chemicals, biological pollutants, or 
effluents into the surface water or into connected groundwater at a 
point source or by dispersed release (non-point source); aerial 
deposition of known toxicants, such as mercury, that are positively 
correlated to regional exceedences of water quality standards for these 
toxicants; livestock grazing that results in waters heavily polluted by 
feces; runoff from agricultural fields; roadside use of salts; aerial 
pesticide overspray; runoff from mine tailings or other mining 
activities; and ash flow and fire retardants from fires and fire 
suppression. These actions could adversely affect the ability of the 
habitat to support survival and reproduction of gartersnake prey 
species. Variances in water chemistry or temperature could also affect 
a leopard frog's ability to survive with disease such as 
Batrachochytrium dendrobatidis (Bd).
    (4) Actions that would remove, diminish, or significantly alter the 
structural complexity of key terrestrial habitat features within 600 
feet (183 m) of aquatic habitat. Terrestrial features may be organic or 
inorganic, may be natural or manmade, and include, but are not limited 
to, boulders and boulder piles, rocks such as river cobble, downed 
trees or logs, debris jams, small mammal burrows, or leaf litter. Such 
activities could include, but are not limited to: Construction 
projects; flood control projects; vegetation management projects; or 
any project that requires a 404 permit from the U.S. Army Corps of 
Engineers. These activities could result in a reduction of the amount 
or distribution of these key habitat features that are important for 
gartersnake thermoregulation, gestation, shelter, protection from 
predators, and foraging opportunities.
    (5) Actions and structures that would physically block movement of 
gartersnakes or their prey species within or between regionally 
proximal populations or suitable habitat. Such actions and structures 
include, but are not limited to: Urban, industrial, or agricultural 
development; reservoirs stocked with predatory fishes, bullfrogs, or 
crayfish that are 50 ac (20 ha) or more in size; highways that do not 
include reptile and amphibian fencing and culverts; and walls, dams, 
fences, canals, or other structures that could physically block 
movement of gartersnakes. These actions and structures could reduce or 
eliminate immigration and emigration among gartersnake populations, or 
that of their prey species, reducing the long-term viability of 
populations.
    (6) Actions that would directly or indirectly result in the 
introduction, spread, or augmentation of harmful

[[Page 41577]]

nonnative species in gartersnake habitat, or in habitat that is 
hydrologically connected, even if those segments are occasionally 
intermittent, or introduction of other species that compete with or 
prey on either gartersnake species or their prey base, or introduce 
disease, particularly chytridiomycosis (the disease caused by Bd) which 
is a serious threat to the amphibian prey base of northern Mexican 
gartersnakes. Possible actions could include, but are not limited to: 
Introduction or stocking of nonnative, spiny-rayed fishes, bullfrogs, 
crayfish, tiger salamanders, or other predators on the prey base of 
northern Mexican or narrow-headed gartersnakes; creating or sustaining 
a sport fishery that encourages use of nonnative live fish, crayfish, 
tiger salamanders, or frogs as bait; maintaining or operating 
reservoirs that act as source populations for harmful nonnative species 
within a watershed; water diversions, canals, or other water conveyance 
that moves water from one place to another and through which 
inadvertent transport of harmful nonnative species into northern 
Mexican or narrow-headed gartersnake habitat may occur; and movement of 
water, mud, wet equipment, or vehicles from one aquatic site to 
another, through which inadvertent transport of Bd may occur. These 
activities directly or indirectly result in unnatural competition with 
and predation from harmful nonnative predators on these gartersnake 
species, leading to significantly reduced recruitment within 
gartersnake populations and diminishment or extirpation of their prey 
base.
    (7) Actions that would deliberately remove, diminish, or 
significantly alter the native or nonnative, soft-rayed fish component 
of the gartersnake prey base within occupied habitat for a period of 7 
days or longer. In general, these actions typically occur in 
association with fisheries management, such as the application of 
piscicides in conjunction with fish barrier construction. These 
activities are designed to completely remove target fish species from a 
treatment area and, if the area is fishless for an extended period of 
time, could result in starvation of a resident gartersnake population.

Exemptions

Application of Section 4(a)(3) of the Act

    The Sikes Act Improvement Act of 1997 (Sikes Act) (16 U.S.C. 670a) 
required each military installation that includes land and water 
suitable for the conservation and management of natural resources to 
complete an integrated natural resources management plan (INRMP) by 
November 17, 2001. An INRMP integrates implementation of the military 
mission of the installation with stewardship of the natural resources 
found on the base. Each INRMP includes:
    (1) An assessment of the ecological needs on the installation, 
including the need to provide for the conservation of listed species;
    (2) A statement of goals and priorities;
    (3) A detailed description of management actions to be implemented 
to provide for these ecological needs; and
    (4) A monitoring and adaptive management plan.
    Among other things, each INRMP must, to the extent appropriate and 
applicable, provide for fish and wildlife management; fish and wildlife 
habitat enhancement or modification; wetland protection, enhancement, 
and restoration where necessary to support fish and wildlife; and 
enforcement of applicable natural resource laws.
    The National Defense Authorization Act for Fiscal Year 2004 (Pub. 
L. 108-136) amended the Act to limit areas eligible for designation as 
critical habitat. Specifically, section 4(a)(3)(B)(i) of the Act (16 
U.S.C. 1533(a)(3)(B)(i)) now provides: ``The Secretary shall not 
designate as critical habitat any lands or other geographic areas owned 
or controlled by the Department of Defense, or designated for its use, 
that are subject to an integrated natural resources management plan 
prepared under section 101 of the Sikes Act (16 U.S.C. 670a), if the 
Secretary determines in writing that such plan provides a benefit to 
the species for which critical habitat is proposed for designation.''
    There are no Department of Defense lands with a completed INRMP 
within the proposed critical habitat designations for the northern 
Mexican and narrow-headed gartersnakes.

Exclusions

Application of Section 4(b)(2) of the Act

    Section 4(b)(2) of the Act states that the Secretary shall 
designate and make revisions to critical habitat on the basis of the 
best available scientific data after taking into consideration the 
economic impact, national security impact, and any other relevant 
impacts of specifying any particular area as critical habitat. The 
Secretary may exclude an area from critical habitat if he determines 
that the benefits of such exclusion outweigh the benefits of specifying 
such area as part of the critical habitat, unless he determines, based 
on the best scientific data available, that the failure to designate 
such area as critical habitat will result in the extinction of the 
species. In making that determination, the statute on its face, as well 
as the legislative history are clear that the Secretary has broad 
discretion regarding which factor(s) to use and how much weight to give 
to any factor.
    In considering whether to exclude a particular area from the 
designation, we identify the benefits of including the area in the 
designation, identify the benefits of excluding the area from the 
designation, and evaluate whether the benefits of exclusion outweigh 
the benefits of inclusion. If the analysis indicates that the benefits 
of exclusion outweigh the benefits of inclusion, the Secretary may 
exercise his discretion to exclude the area only if such exclusion 
would not result in the extinction of the species.
    When identifying the benefits of inclusion for an area, we consider 
the additional regulatory benefits that area would receive from the 
protection from adverse modification or destruction as a result of 
actions with a Federal nexus; the educational benefits of mapping 
essential habitat for recovery of the listed species; and any benefits 
that may result from a designation due to State or Federal laws that 
may apply to critical habitat.
    When identifying the benefits of exclusion, we consider, among 
other things, whether exclusion of a specific area is likely to result 
in conservation; the continuation, strengthening, or encouragement of 
partnerships; or implementation of a management plan that provides 
equal to or more conservation than a critical habitat designation would 
provide.
    In the case of northern Mexican and narrow-headed gartersnakes, the 
benefits of critical habitat include public awareness of these 
gartersnakes' presence and the importance of habitat protection, and, 
in cases where a Federal nexus exists, increased habitat protection due 
to the protection from adverse modification or destruction of critical 
habitat.
    The consultation provisions under section 7(a) of the Act 
constitute the regulatory benefits of critical habitat. Federal 
agencies must consult with us on discretionary actions that may affect 
critical habitat and must avoid destroying or adversely modifying 
critical habitat. Federal agencies must also consult with the Service 
on discretionary actions that may affect a listed species and refrain 
from undertaking actions that are likely to jeopardize the continued 
existence of such species. The analysis of effects to

[[Page 41578]]

critical habitat is a separate and different analysis from that of the 
effects to the species. Therefore, the difference in outcomes of these 
two analyses represents the regulatory benefit of critical habitat. For 
some species, and in some locations, the outcome of these analyses will 
be similar, because effects on habitat will often result in effects on 
the species. However, the regulatory standard is different. The 
jeopardy analysis looks at the action's impact on survival and recovery 
of the species, while the adverse modification analysis examines the 
action's effects on the designated habitat's contribution to the 
species' conservation. This will, in many instances, lead to different 
results and different regulatory requirements. Thus, critical habitat 
designations may provide greater regulatory benefits to the recovery of 
a species.
    There are two limitations to the regulatory effect of critical 
habitat. First, a section 7(a)(2) consultation is required only where 
there is a Federal nexus (an action authorized, funded, or carried out 
by any Federal agency). If there is no Federal nexus, the critical 
habitat designation of non-Federal lands itself does not restrict any 
actions that destroy or adversely modify critical habitat. However, 
this does not apply in situations where non-Federal lands have a 
Federal nexus (e.g., a private project on non-Federal lands that 
requires the issuance of a permit from a Federal agency). Second, the 
designation only limits destruction or adverse modification. Critical 
habitat designation alone does not require property owners to undertake 
affirmative actions to promote the recovery of the species.
    The designation of critical habitat does not require that any 
management or recovery actions take place on the lands included in the 
designation. Even in cases where consultation has been initiated under 
section 7(a)(2) of the Act, the end result of consultation is to avoid 
jeopardy to the species or adverse modification of its critical habitat 
or both, but not necessarily to manage critical habitat or institute 
recovery actions on critical habitat. Conversely, voluntary 
conservation efforts implemented through management plans may institute 
proactive actions over the lands they encompass and are often put in 
place to remove or reduce known threats to a species or its habitat, 
therefore implementing recovery actions.
    Another benefit of including lands in critical habitat is that 
serves to educate landowners, State and local governments, and the 
public regarding the potential conservation value of an area. This 
helps focus and promote conservation efforts by other parties by 
clearly delineating areas of high conservation value for the affected 
species. For example, critical habitat designation can help inform 
State agencies and local governments about areas that could be 
conserved under State laws or local ordinances.
    Most federally listed species in the United States will not recover 
without the cooperation of non-Federal landowners. Geo-referenced data 
indicate that than 60 percent of the United States is privately owned, 
and at least 80 percent of endangered or threatened species occur 
either partially or solely on private lands. U.S. Department of 
Interior data indicate that only about 12 percent of listed species 
were found almost exclusively on Federal lands (90 to 100 percent of 
their known occurrences restricted to Federal lands) and that 50 
percent of federally listed species are not known to occur on Federal 
lands at all.
    The majority of northern Mexican and narrow-headed gartersnake 
habitat and localities are on Federal lands, mostly lands managed by 
the U.S. Forest Service or Bureau of Land Management. However, key 
aquatic sites are sometimes on non-Federal lands. This is particularly 
true for Arizona, where proposed critical habitat units include, in 
some cases, significant amounts of entirely non-Federal lands.
    Building partnerships and promoting voluntary cooperation of 
landowners are essential to understanding the status of species on non-
Federal lands, and necessary for implementing recovery actions, such as 
reestablishing listed species and restoring and protecting habitat. 
Many non-Federal landowners derive satisfaction from contributing to 
endangered species recovery. We strive to promote these private-sector 
efforts through the Department of the Interior's Cooperative 
Conservation philosophy. Conservation agreements with non-Federal 
landowners (HCPs, safe harbor agreements, other conservation 
agreements, easements, and State and local regulations) enhance species 
conservation by extending species protections beyond those available 
through section 7(a)(2) consultations. In the past decade and a half, 
we have encouraged non-Federal landowners to enter into conservation 
agreements, based on our philosophy that voluntary conservation can 
benefit both landowners and wildlife, and that we can achieve greater 
species conservation on non-Federal land through such partnerships than 
we can through regulatory methods (61 FR 63854; December 2, 1996). The 
Chiricahua leopard frog provides an example; we have often used the 
Service's Partners for Fish and Wildlife grant program to work with 
non-Federal partners on recovery projects for this species. This grant 
program requires a commitment from the participating landowner to 
maintain the improvements funded by the program for 10 years. We have 
also worked with private landowners on Chiricahua leopard frog 
conservation via safe harbor agreements in Arizona and southwestern New 
Mexico, a conservation agreement for the Chiricahua leopard frog that 
protects frogs and their habitats on private and public lands in the 
Huachuca Mountains of Arizona, and HCPs in southeastern Arizona and 
southwestern New Mexico. Collectively, these projects, programs, and 
agreements benefit the northern Mexican gartersnake by meaningfully 
contributing to the recovery of an important prey species, which also 
indirectly benefits a Suite of native riparian or aquatic species by 
strengthening their ecosystem.
    Many private landowners, however, are wary of the possible 
consequences of attracting or maintaining endangered species to their 
property. Mounting evidence suggests that some regulatory actions by 
the Federal government, while well-intentioned and required by law, can 
(under certain circumstances) have unintended negative consequences for 
the conservation of species on private lands (Wilcove et al. 1996, pp. 
5-6; Bean 2002, pp. 2-3; Conner and Mathews 2002, pp. 1-2; James 2002, 
pp. 270-271; Koch 2002, pp. 2-3; Brooke et al. 2003, pp. 1639-1643). 
Many landowners fear a decline in their property value due to real or 
perceived restrictions on land-use options where endangered or 
threatened species are found. Consequently, harboring endangered 
species is viewed by many landowners as a liability. This perception 
results in anti-conservation incentives, because maintaining habitats 
that harbor endangered species represents a risk to future economic 
opportunities (Main et al. 1999, pp. 1264-1265; Brook et al. 2003, pp. 
1644-1648).
    According to some researchers, the designation of critical habitat 
on private lands significantly reduces the likelihood that landowners 
will support and carry out conservation actions (Main et al. 1999, p. 
1263; Bean 2002, p. 2; Brook et al. 2003, pp. 1644-1648). The magnitude 
of this outcome is greatly amplified in situations where active 
management measures (such as reestablishment, fire management, control 
of harmful nonnative species)

[[Page 41579]]

are necessary for species conservation (Bean 2002, pp. 3-4). Such is 
the case for the northern Mexican and narrow-headed gartersnakes. We 
believe that the judicious exclusion of specific areas of non-federally 
owned lands from critical habitat designations can contribute to the 
species' recovery and provide a superior level of conservation.
    The purpose of designating critical habitat is to contribute to the 
conservation of endangered and threatened species and the ecosystems 
upon which they depend. The outcome of the designation, triggering 
regulatory requirements for actions authorized, funded, or carried out 
by Federal agencies under section 7(a)(2) of the Act, can sometimes be 
counterproductive to its intended purpose on non-Federal lands. Thus, 
the benefits of excluding areas that are covered by effective 
partnerships or other conservation commitments can often be high.
    Some areas proposed for critical habitat can be excluded based on 
an existing management plan. When we evaluate a management plan during 
our consideration of the benefits of exclusion, we assess a variety of 
factors, including, but not limited to, whether the plan is finalized, 
how it provides for the conservation of the essential physical or 
biological features, whether there is a reasonable expectation that the 
conservation management strategies and actions contained in a 
management plan will be implemented into the future, whether the 
conservation strategies in the plan are likely to be effective, and 
whether the plan contains a monitoring program or adaptive management 
to ensure that the conservation measures are effective and can be 
adapted in the future in response to new information.
    After identifying the benefits of inclusion and the benefits of 
exclusion, we carefully weigh the two sides to evaluate whether the 
benefits of exclusion outweigh those of inclusion. If our analysis 
indicates that the benefits of exclusion outweigh the benefits of 
inclusion, we then determine whether exclusion would result in 
extinction. If exclusion of an area from critical habitat will result 
in extinction, we will not exclude it from the designation.
    Based on the information provided by entities seeking exclusion, as 
well as any additional public comments received, we will evaluate 
whether certain lands within the proposed critical habitat areas of the 
Upper Gila River, Agua Fria River, Upper Salt River, Verde River, Upper 
Santa Cruz River, Redrock Canyon, Cienega Creek, San Pedro River, and 
Babocomari River subbasins for the northern Mexican gartersnake; and 
the Upper Gila River, Middle Gila River, Upper Salt River, and Verde 
River subbasins for the narrow-headed gartersnake are appropriate for 
exclusion from the final designation pursuant to section 4(b)(2) of the 
Act. If the analysis indicates that the benefits of excluding lands 
from the final designation outweigh the benefits of designating those 
lands as critical habitat, then the Secretary may exercise his 
discretion to exclude the lands from the final designation.
    After reviewing the following areas under section 4(b)(2) of the 
Act, we are considering excluding them from the critical habitat 
designation for northern Mexican and narrow-headed gartersnakes. Tables 
4a and 4b below provide approximate areas (ac, ha) of lands that meet 
the definition of critical habitat, but which are under our 
consideration for possible exclusion under section 4(b)(2) of the Act 
from the final critical habitat rule.

    Table 4a--Areas Considered for Exclusion (by Critical Habitat Unit) for the Northern Mexican Gartersnake
----------------------------------------------------------------------------------------------------------------
                                                                                Areas meeting
                                                                               the definition   Areas considered
                                                                                 of critical      for possible
               Unit/Subunit                          Specific area               habitat, in      exclusion, in
                                                                                    acres             acres
                                                                                 (hectares)        (hectares)
----------------------------------------------------------------------------------------------------------------
Upper Gila River Unit/Gila River.........  The Nature Conservancy's Gila              133 (54)          133 (54)
                                            Riparian Preserve.
Agua Fria River Subbasin Unit/Agua Fria    Arizona Game and Fish                       88 (36)           88 (36)
 River Mainstem.                            Department's Horseshoe Ranch
                                            Property.
Upper Salt River Subbasin Unit/Black       White Mountain Apache and San                13,760            13,760
 River.                                     Carlos Apache Indian                       (5,569)           (5,569)
                                            Reservations.
Upper Salt River Subbasin Unit/Big Bonito  White Mountain Apache Reservation             5,826             5,826
 Creek.                                                                                (2,358)           (2,358)
Verde River Subbasin Unit/Verde River....  Yavapai Apache Reservation.......          192 (78)               192
                                                                                                            (78)
Verde River Subbasin Unit/Verde River....  Arizona Game and Fish                     372 (150)         372 (150)
                                            Department's Upper Verde
                                            Wildlife Area.
Verde River Subbasin Unit/Verde River....  The Nature Conservancy's Verde             209 (84)          209 (84)
                                            Springs Preserve and Verde
                                            Valley Property.
Verde River Subbasin Unit/Verde River....  Salt River Project's Camp Verde             76 (31)           76 (31)
                                            Riparian Preserve.
Verde River Subbasin Unit/Oak Creek......  Arizona Game and Fish                      149 (60)          149 (60)
                                            Department's Bubbling Ponds and
                                            Page Springs State Fish
                                            Hatcheries.
Upper Santa Cruz River Subbasin Unit.....  San Rafael Ranch.................            18,491            18,491
                                                                                       (7,483)           (7,483)
Redrock Canyon Subbasin Unit.............  The Nature Conservancy's                    65 (26)           65 (26)
                                            Patagonia-Sonoita Creek Preserve.
Cienega Creek Subbasin Unit/Cienega Creek  Pima County's Cienega Creek                   4,260             4,260
 Natural Preserve.                          Natural Preserve.                          (1,724)           (1,724)
San Pedro River Subbasin Unit/San Pedro    The Nature Conservancy's San                  1,688             1,688
 River.                                     Pedro River Preserve, A7 Ranch,              (683)             (683)
                                            Cascabel, Dudleyville, and Upper
                                            San Pedro Properties.
San Pedro River Subbasin Unit/San Pedro    San Carlos Apache Indian                    76 (31)           76 (31)
 River.                                     Reservation.
San Pedro River Subbasin Unit/San Pedro    Salt River Project's Spirit                190 (77)          190 (77)
 River.                                     Hollow Preserve and Annex,
                                            Stillinger Preserve, and Adobe
                                            Preserve.
Babocomari River Subbasin Unit/Appleton-   Appleton-Whittell Research Ranch      7,754 (3,138)     2,515 (1,018)
 Whittell Research Ranch.                   (includes portions of Post
                                            Canyon, O'Donnel Canyon, and
                                            Turkey Creek).

[[Page 41580]]

 
Babocomari River Subbasin Unit/Canelo      The Nature Conservancy's Canelo            213 (86)          213 (86)
 Hills Cienega Preserve.                    Hills Cienega Preserve.
----------------------------------------------------------------------------------------------------------------


      Table 4b--Areas Considered for Exclusion (by Critical Habitat Unit) for the Narrow-Headed Gartersnake
----------------------------------------------------------------------------------------------------------------
                                                                                Areas meeting
                                                                               the definition   Areas considered
                                                                                 of critical      for possible
               Unit/Subunit                          Specific area               habitat, in      exclusion, in
                                                                                    acres             acres
                                                                                 (hectares)        (hectares)
----------------------------------------------------------------------------------------------------------------
Upper Gila River Subbasin Unit/Gila River  The Nature Conservancy's Gila              133 (54)          133 (54)
                                            Riparian Preserve.
Middle Gila River Subbasin Unit/Eagle      San Carlos Apache Reservation....             2,558             2,558
 Creek.                                                                                (1,035)           (1,035)
Upper Salt River Subbasin Unit/Salt River  White Mountain Apache and San                 7,502             7,502
                                            Carlos Apache Indian                       (3,036)           (3,036)
                                            Reservations.
Upper Salt River Subbasin Unit/Black       White Mountain Apache and San                13,752            13,752
 River.                                     Carlos Apache Indian                       (5,565)           (5,565)
                                            Reservations.
Upper Salt River Subbasin Unit/White       White Mountain Apache Reservation             2,588             2,588
 River.                                                                                (1,047)           (1,047)
Upper Salt River Subbasin Unit/Canyon      White Mountain Apache Reservation             6,160             6,160
 Creek.                                                                                (2,493)           (2,493)
Upper Salt River Subbasin Unit/Carrizo     White Mountain Apache Reservation             8,875             8,875
 Creek.                                                                                (3,592)           (3,592)
Upper Salt River Subbasin Unit/Cibeque     White Mountain Apache Reservation             6,669             6,669
 Creek.                                                                                (2,699)           (2,699)
Upper Salt River Subbasin Unit/Diamond     White Mountain Apache Reservation             3,117             3,117
 Creek.                                                                                (1,261)           (1,261)
Verde River Subbasin Unit/Verde River....  Yavapai Apache Reservation.......               192               192
                                                                                          (78)              (78)
Verde River Subbasin Unit/Verde River....  Arizona Game and Fish                     372 (150)         372 (150)
                                            Department's Upper Verde River
                                            Wildlife Area.
Verde River Subbasin Unit/Verde River....  Salt River Project's Camp Verde             76 (31)           76 (31)
                                            Riparian Preserve.
Verde River Subbasin Unit/Verde River....  The Nature Conservancy's Verde             209 (84)          209 (84)
                                            Springs Preserve and Verde
                                            Valley Property.
----------------------------------------------------------------------------------------------------------------

    We are considering these areas for exclusion because we believe 
that:
    (1) Their value for conservation will be preserved in the future by 
existing protective actions, or
    (2) They are appropriate for exclusion under the ``other relevant 
factor'' provision of section 4(b)(2) of the Act.
    However, we specifically solicit comments on the inclusion or 
exclusion of such areas.
Exclusions Based on Economic Impacts
    Under section 4(b)(2) of the Act, we consider the economic impacts 
of specifying any particular area as critical habitat. In order to 
consider economic impacts, we are preparing an analysis of the economic 
impacts of the proposed critical habitat designation and related 
factors. Potential land use sectors that may be affected by this 
proposed rulemaking include development, livestock grazing, mining, 
timber, recreation, flood control, fisheries management, and 
agriculture.
    We will announce the availability of the draft economic analysis as 
soon as it is completed, at which time we will seek public review and 
comment. At that time, copies of the draft economic analysis will be 
available for downloading from the Internet at http://www.regulations.gov, or by contacting the Arizona Ecological Services 
Field Office directly (see FOR FURTHER INFORMATION CONTACT). During the 
development of a final designation, we will consider economic impacts, 
public comments, and other new information, and areas may be excluded 
from the final critical habitat designation under section 4(b)(2) of 
the Act and our implementing regulations at 50 CFR 424.19.
Exclusions Based on National Security Impacts
    Under section 4(b)(2) of the Act, we consider whether there are 
lands owned or managed by the Department of Defense (DOD) where a 
national security impact might exist.
    In preparing this proposal, we have determined that the lands 
within the proposed designation of critical habitat for the northern 
Mexican and narrow-headed gartersnakes are not owned or managed by the 
Department of Defense, and, therefore, we anticipate no impact on 
national security. Consequently, the Secretary does not propose to 
exert his discretion to exclude any areas from the final designation 
based on impacts on national security.
Exclusions Based on Other Relevant Impacts
    Under section 4(b)(2) of the Act, we consider any other relevant 
impacts, in addition to economic impacts and impacts on national 
security. We consider a number of factors including whether the 
landowners have developed any HCPs or other management plans for the 
area, or whether there are conservation partnerships that would be

[[Page 41581]]

encouraged by designation of, or exclusion from, critical habitat. In 
addition, we look at any tribal issues, and consider the government-to-
government relationship of the United States with tribal entities. We 
also consider any social impacts that might occur because of the 
designation.
Land and Resource Management Plans, Conservation Plans, Agreements 
Based on Conservation Partnerships, or General Land Management That 
Favors a Native Biological Community
    We consider a current land management or conservation plan (HCPs, 
as well as other types) to provide adequate management or protection if 
it meets the following criteria:
    (1) The plan is complete and provides the same or better level of 
protection from adverse modification or destruction than that provided 
through a consultation under section 7 of the Act;
    (2) There is a reasonable expectation that the conservation 
management strategies and actions will be implemented for the 
foreseeable future, based on past practices, written guidance, or 
regulations; and
    (3) The plan provides conservation strategies and measures 
consistent with currently accepted principles of conservation biology.
    We consider management plans that are designed for native fish as 
having nearly equal value to the northern Mexican or narrow-headed 
gartersnake because actions taken to protect or improve the status of 
native fish are commensurate with conservation of these gartersnakes. 
Native fish are sensitive to water availability, habitat modification, 
and harmful nonnative species in a similar manner as these 
gartersnakes; for the northern Mexican gartersnake, this also includes 
its ranid prey species. The commonality shared between the ecological 
needs and threats faced by all native riparian and aquatic species 
broadly supports the notion that what is good for one taxon is largely 
beneficial to another. This is particularly true for these two 
gartersnake species, where managing for native prey species not only 
provides conservation of important physical habitat elements, but also 
maintains an adequate prey base for the snakes themselves.
    During the preparation of the 2007 critical habitat designation for 
spikedace and loach minnow (72 FR 13355; March 21, 2007), we received 
management plans from the White Mountain Apache Tribe, San Carlos 
Apache Tribe, and Freeport McMoRan (formerly Phelps Dodge). 
Additionally, a Tribal Resolution was prepared by the Yavapai Apache 
Nation. These management plans were ultimately used to exclude areas 
under section 4(b)(2) of the Act from critical habitat designation for 
the spikedace and loach minnow (77 FR 10810; February 23, 2012). We 
also consider the San Rafael Ranch's safe harbor agreement for Gila 
topminnow in its potential benefits to the northern Mexican gartersnake 
in the San Rafael Valley. We will consider these materials and any 
other relevant information pertaining to these entities during the 
development of the final rule to determine if any of these areas should 
be excluded from the final critical habitat designation under section 
4(b)(2) of the Act.
    In addition, the Arizona Game and Fish Department has initiated 
candidate conservation planning for the northern Mexican gartersnake on 
its Horseshoe Ranch property and Bubbling Ponds and Page Springs State 
Fish Hatcheries. We have received and reviewed a draft management plan 
for the northern Mexican gartersnake for these properties. We also 
recognize our strong conservation partners in the Pima County's Cienega 
Creek Natural Preserve, the Appleton-Whittell Research Ranch, and 
various properties managed by The Nature Conservancy, all of whom 
manage exclusively for native species, which, by default, we recognize 
as managing specifically against harmful nonnative species, the primary 
threat to the northern Mexican and narrow-headed gartersnakes. In 
addition, we recognize the Arizona Game and Fish Department's 
management of Upper Verde River Wildlife Area, as also favoring native 
fish species, thereby benefitting both the northern Mexican and narrow-
headed gartersnakes by improving their regional prey base.
    Finally, a large portion of the Verde River and several of its 
perennial tributaries are included in the area covered by the Salt 
River Project's (SRP) Horseshoe-Bartlett HCP for operation of Horseshoe 
and Bartlett Dams. While implementation of the Horseshoe-Bartlett HCP 
will provide some indirect benefit for northern Mexican and narrow-
headed gartersnakes from implementation of conservation measures for 
their prey species, the HCP does not involve all land owners within the 
covered area, and therefore does not allow for exclusion of the entire 
covered area under section 4(b)(2) of the Act. However, SRP has 
acquired property which they manage along the Verde and San Pedro 
Rivers as mitigation for their Horseshoe-Bartlett and Roosevelt HCPs. 
These properties are managed for the promotion of riparian vegetation 
and provide direct benefits to resident gartersnake populations and 
their prey species. We will consider these properties and any other 
relevant information during the development of the final rule to 
determine if this area should be excluded from the final critical 
habitat designation under section 4(b)(2) of the Act.

Peer Review

    In accordance with our joint policy on peer review published in the 
Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert 
opinions of at least three appropriate and independent specialists 
regarding this proposed rule. The purpose of peer review is to ensure 
that our critical habitat designation is based on scientifically sound 
data, assumptions, and analyses. We invite these peer reviewers to 
comment during this public comment period on our specific assumptions 
and conclusions in this proposed designation of critical habitat.
    We will consider all comments and information we receive during 
this comment period on this proposed rule during our preparation of a 
final determination. Accordingly, the final decision may differ from 
this proposal.

Public Hearings

    Section 4(b)(5) of the Act provides for one or more public hearings 
on this proposal, if requested. Requests must be received within 45 
days after the date of publication of this proposed rule in the Federal 
Register. Such requests must be sent to the address shown in the FOR 
FURTHER INFORMATION CONTACT section. We will schedule public hearings 
on this proposal, if any are requested, and announce the dates, times, 
and places of those hearings, as well as how to obtain reasonable 
accommodations, in the Federal Register and local newspapers at least 
15 days before the hearing.

Required Determinations

Regulatory Planning and Review--Executive Orders 12866 and 13563

    Executive Order 12866 provides that the Office of Information and 
Regulatory Affairs will review all significant rules. The Office of 
Information and Regulatory Affairs has determined that this rule is not 
significant.
    Executive Order 13563 reaffirms the principles of Executive Order 
12866 while calling for improvements in the nation's regulatory system 
to promote predictability, to reduce uncertainty, and to use the best, 
most innovative, and least burdensome tools for achieving regulatory 
ends. The

[[Page 41582]]

executive order directs agencies to consider regulatory approaches that 
reduce burdens and maintain flexibility and freedom of choice for the 
public where these approaches are relevant, feasible, and consistent 
with regulatory objectives. Executive Order 13563 emphasizes further 
that regulations must be based on the best available science and that 
the rulemaking process must allow for public participation and an open 
exchange of ideas. We have developed this rule in a manner consistent 
with these requirements.

Regulatory Flexibility Act (5 U.S.C. 601 et seq.)

    Under the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.) as 
amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996 (5 U.S.C 801 et seq.), whenever an agency must publish 
a notice of rulemaking for any proposed or final rule, it must prepare 
and make available for public comment a regulatory flexibility analysis 
that describes the effects of the rule on small entities (small 
businesses, small organizations, and small government jurisdictions). 
However, no regulatory flexibility analysis is required if the head of 
the agency certifies the rule will not have a significant economic 
impact on a substantial number of small entities. The SBREFA amended 
the RFA to require Federal agencies to provide a certification 
statement of the factual basis for certifying that the rule will not 
have a significant economic impact on a substantial number of small 
entities.
    According to the Small Business Administration, small entities 
include small organizations such as independent nonprofit 
organizations; small governmental jurisdictions, including school 
boards and city and town governments that serve fewer than 50,000 
residents; and small businesses (13 CFR 121.201). Small businesses 
include such businesses as manufacturing and mining concerns with fewer 
than 500 employees, wholesale trade entities with fewer than 100 
employees, retail and service businesses with less than $5 million in 
annual sales, general and heavy construction businesses with less than 
$27.5 million in annual business, special trade contractors doing less 
than $11.5 million in annual business, and forestry and logging 
operations with fewer than 500 employees and annual business less than 
$7 million. To determine whether small entities may be affected, we 
will consider the types of activities that might trigger regulatory 
impacts under this designation as well as types of project 
modifications that may result. In general, the term ``significant 
economic impact'' is meant to apply to a typical small business firm's 
business operations.
    Importantly, the incremental impacts of a rule must be both 
significant and substantial to prevent certification of the rule under 
the RFA and to require the preparation of an initial regulatory 
flexibility analysis. If a substantial number of small entities are 
affected by the proposed critical habitat designation, but the per-
entity economic impact is not significant, the Service may certify. 
Likewise, if the per-entity economic impact is likely to be 
significant, but the number of affected entities is not substantial, 
the Service may also certify.
    The Service's current understanding of recent case law is that 
Federal agencies are only required to evaluate the potential impacts of 
rulemaking on those entities directly regulated by the rulemaking; 
therefore, they are not required to evaluate the potential impacts to 
those entities not directly regulated. The designation of critical 
habitat for an endangered or threatened species only has a regulatory 
effect where a Federal action agency is involved in a particular action 
that may affect the designated critical habitat.
    Under these circumstances, only the Federal action agency is 
directly regulated by the designation, and, therefore, consistent with 
the service's current interpretation of RFA and recent case law, the 
Service may limit its evaluation of the potential impacts to those 
identified for federal action agencies. Under this interpretation, 
there is no requirement under the RFA to evaluate the potential impacts 
to entities not directly regulated, such as small businesses. However, 
Executive Orders 12866 and 13563 direct Federal agencies to assess 
costs and benefits of available regulatory alternatives in quantitative 
(to the extent feasible) and qualitative terms. Consequently, it is the 
current practice of the Service to assess to the extent practicable 
these potential impacts if sufficient data are available, whether or 
not this analysis is believed by the Service to be strictly required by 
the RFA. In other words, while the effects analysis required under the 
RFA is limited to entities directly regulated by the rulemaking, the 
effects analysis under the Act, consistent with the E.O. regulatory 
analysis requirements, can take into consideration impacts to both 
directly and indirectly impacted entities, where practicable and 
reasonable.
    In conclusion, we believe that, based on our interpretation of 
directly regulated entities under the RFA and relevant case law, this 
designation of critical habitat will only directly regulate Federal 
agencies, which are not by definition small business entities. And as 
such, we certify that, if promulgated, this designation of critical 
habitat would not have a significant economic impact on a substantial 
number of small business entities. Therefore, an initial regulatory 
flexibility analysis is not required. However, though not necessarily 
required by the RFA, in our draft economic analysis for this proposal, 
we will consider and evaluate the potential effects to third parties 
that may be involved with consultations with Federal action agencies 
related to this action.

Energy Supply, Distribution, or Use--Executive Order 13211

    Executive Order 13211 (Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use) requires 
agencies to prepare Statements of Energy Effects when undertaking 
certain actions. We do not expect the designation of this proposed 
critical habitat to significantly affect energy supplies, distribution, 
or use. Therefore, this action is not a significant energy action, and 
no Statement of Energy Effects is required. However, we will further 
evaluate this issue as we conduct our economic analysis, and review and 
revise this assessment as warranted.

Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq.)

    In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501 
et seq.), we make the following findings:
    (1) This proposed rule would not produce a Federal mandate. In 
general, a Federal mandate is a provision in legislation, statute, or 
regulation that would impose an enforceable duty upon State, local, or 
tribal governments, or the private sector, and includes both ``Federal 
intergovernmental mandates'' and ``Federal private sector mandates.'' 
These terms are defined in 2 U.S.C. 658(5)-(7). ``Federal 
intergovernmental mandate'' includes a regulation that ``would impose 
an enforceable duty upon State, local, or tribal governments'' with two 
exceptions. It excludes ``a condition of Federal assistance.'' It also 
excludes ``a duty arising from participation in a voluntary Federal 
program,'' unless the regulation ``relates to a then-existing Federal 
program under which $500,000,000 or more is provided annually to State, 
local, and tribal governments under entitlement authority,'' if the 
provision would ``increase the stringency of conditions of

[[Page 41583]]

assistance'' or ``place caps upon, or otherwise decrease, the Federal 
Government's responsibility to provide funding,'' and the State, local, 
or tribal governments ``lack authority'' to adjust accordingly. At the 
time of enactment, these entitlement programs were: Medicaid; Aid to 
Families with Dependent Children work programs; Child Nutrition; Food 
Stamps; Social Services Block Grants; Vocational Rehabilitation State 
Grants; Foster Care, Adoption Assistance, and Independent Living; 
Family Support Welfare Services; and Child Support Enforcement. 
``Federal private sector mandate'' includes a regulation that ``would 
impose an enforceable duty upon the private sector, except (i) a 
condition of Federal assistance or (ii) a duty arising from 
participation in a voluntary Federal program.''
    The designation of critical habitat does not impose a legally 
binding duty on non-Federal Government entities or private parties. 
Under the Act, the only regulatory effect is that Federal agencies must 
ensure that their actions do not destroy or adversely modify critical 
habitat under section 7. While non-Federal entities that receive 
Federal funding, assistance, or permits, or that otherwise require 
approval or authorization from a Federal agency for an action, may be 
indirectly impacted by the designation of critical habitat, the legally 
binding duty to avoid destruction or adverse modification of critical 
habitat rests squarely on the Federal agency. Furthermore, to the 
extent that non-Federal entities are indirectly impacted because they 
receive Federal assistance or participate in a voluntary Federal aid 
program, the Unfunded Mandates Reform Act would not apply, nor would 
critical habitat shift the costs of the large entitlement programs 
listed above onto State governments.
    (2) We lack the available economic information to determine if a 
Small Government Agency Plan is required. Therefore, we defer this 
finding until completion of the draft economic analysis is prepared 
under section 4(b)(2) of the Act.

Takings--Executive Order 12630

    In accordance with Executive Order 12630 (Government Actions and 
Interference with Constitutionally Protected Private Property Rights), 
we will analyze the potential takings implications of designating 
critical habitat for the northern Mexican and narrow-headed 
gartersnakes in a takings implications assessment. The draft economic 
analysis will provide the foundation for us to use in preparing a 
takings implication assessment. We will defer the preparation of the 
takings implication assessment until we have evaluated the comments on 
the draft economic analysis. Critical habitat designation does not 
affect landowner actions that do not require Federal funding or 
permits, nor does it preclude development of habitat conservation 
programs or issuance of incidental take permits to permit actions that 
do require Federal funding or permits to go forward.

Federalism--Executive Order 13132

    In accordance with Executive Order 13132 (Federalism), this 
proposed rule does not have significant Federalism effects. A 
federalism summary impact statement is not required. In keeping with 
Department of the Interior and Department of Commerce policy, we 
requested information from, and coordinated development of, this 
proposed critical habitat designation with appropriate State resource 
agencies in New Mexico and Arizona. The designation of critical habitat 
in areas currently occupied by the northern Mexican and narrow-headed 
gartersnakes imposes no additional restrictions to those currently in 
place and, therefore, has little incremental impact on State and local 
governments and their activities. The designation may have some benefit 
to these governments because the areas that contain the physical or 
biological features essential to the conservation of the species are 
more clearly defined, and the elements of the features of the habitat 
necessary to the conservation of the species are specifically 
identified. This information does not alter where and what federally 
sponsored activities may occur. However, it may assist local 
governments in long-range planning (rather than having them wait for 
case-by-case section 7 consultations to occur).
    Where State and local governments require approval or authorization 
from a Federal agency for actions that may affect critical habitat, 
consultation under section 7(a)(2) would be required. While non-Federal 
entities that receive Federal funding, assistance, or permits, or that 
otherwise require approval or authorization from a Federal agency for 
an action, may be indirectly impacted by the designation of critical 
habitat, the legally binding duty to avoid destruction or adverse 
modification of critical habitat rests squarely on the Federal agency.

Civil Justice Reform--Executive Order 12988

    In accordance with Executive Order 12988 (Civil Justice Reform), 
the Office of the Solicitor has determined that the rule does not 
unduly burden the judicial system and that it meets the requirements of 
sections 3(a) and 3(b)(2) of the Order. We are designating critical 
habitat in accordance with the provisions of the Act. To assist the 
public in understanding the habitat needs of the species, the rule 
identifies the elements of physical or biological features essential to 
the conservation of the species. The designated areas of critical 
habitat are presented on maps, and the rule provides several options 
for the interested public to obtain more detailed location information, 
if desired.

Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)

    This rule does not contain any new collections of information that 
require approval by OMB under the Paperwork Reduction Act of 1995 (44 
U.S.C. 3501 et seq.). This rule will not impose recordkeeping or 
reporting requirements on State or local governments, individuals, 
businesses, or organizations. An agency may not conduct or sponsor, and 
a person is not required to respond to, a collection of information 
unless it displays a currently valid OMB control number.

National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.)

    It is our position that, outside the jurisdiction of the U.S. Court 
of Appeals for the Tenth Circuit, we do not need to prepare 
environmental analyses pursuant to NEPA in connection with designating 
critical habitat under the Endangered Species Act. We published a 
notice outlining our reasons for this determination in the Federal 
Register on October 25, 1983 (48 FR 49244). This position was upheld by 
the U.S. Court of Appeals for the Ninth Circuit (Douglas County v. 
Babbitt, 48 F.3d 1495 (9th Cir. 1995), cert. denied 516 U.S. 1042 
(1996)). However, when the range of the species includes States within 
the Tenth Circuit, such as that of the northern Mexican and narrow-
headed gartersnakes, under the Tenth Circuit ruling in Catron County 
Board of Commissioners v. U.S. Fish and Wildlife Service, 75 F.3d 1429 
(10th Cir. 1996), we will undertake a NEPA analysis for critical 
habitat designation and notify the public of the availability of the 
draft environmental assessment for this proposal when it is finished.

[[Page 41584]]

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951), Executive Order 13175 (Consultation and 
Coordination with Indian Tribal Governments), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with recognized Federal 
Tribes on a government-to-government basis. In accordance with 
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights, 
Federal-Tribal Trust Responsibilities, and the Endangered Species Act), 
we readily acknowledge our responsibilities to work directly with 
tribes in developing programs for healthy ecosystems, to acknowledge 
that tribal lands are not subject to the same controls as Federal 
public lands, to remain sensitive to Indian culture, and to make 
information available to tribes.
    The tribal lands in Arizona included in this proposed designation 
of critical habitat are the lands of the White Mountain Apache Tribe, 
San Carlos Apache Tribe, and Yavapai Apache Nation. We used the 
criteria found in the Criteria Used To Identify Critical Habitat 
section to identify tribal lands that are occupied by the northern 
Mexican and narrow-headed gartersnakes that contain the features 
essential for the conservation of these species. We began government-
to-government consultation with these tribes on November 29, 2011, in a 
pre-notification letter informing the tribes that we had begun an 
evaluation of the northern Mexican and narrow-headed gartersnakes for 
listing purposes under the Act. We will consider these areas for 
exclusion from the final critical habitat designation to the extent 
consistent with the requirements of section 4(b)(2) of the Act. We sent 
notification letters on March 12, 2013, to each tribe that described 
the exclusion process under section 4(b)(2) of the Act and invited them 
to meet to discuss the listing process and engage in conversation with 
us about the proposal to the extent possible without disclosing 
predecisional information. We will schedule meetings with these tribes 
and any other interested tribes as early as legally possible so that we 
can give them as much time as possible to comment.

Clarity of the Rule

    We are required by Executive Orders 12866 and 12988 and by the 
Presidential Memorandum of June 1, 1998, to write all rules in plain 
language. This means that each rule we publish must:
    (1) Be logically organized;
    (2) Use the active voice to address readers directly;
    (3) Use clear language rather than jargon;
    (4) Be divided into short sections and sentences; and
    (5) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in the ADDRESSES section. To 
better help us revise the rule, your comments should be as specific as 
possible. For example, you should tell us the numbers of the sections 
or paragraphs that are unclearly written, which sections or sentences 
are too long, the sections where you feel lists or tables would be 
useful, etc.

References Cited

    A complete list of references cited in this rulemaking is available 
on the Internet at http://www.regulations.gov and upon request from the 
Arizona Ecological Services Field Office (see FOR FURTHER INFORMATION 
CONTACT).

Authors

    The primary authors of this package are the staff members of the 
Arizona Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Proposed Regulation Promulgation

    Accordingly, we propose to amend part 17, subchapter B of chapter 
I, title 50 of the Code of Federal Regulations, as set forth below:

PART 17--[AMENDED]

0
1. The authority citation for part 17 continues to read as follows:

    Authority:  16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, 
unless otherwise noted.

0
2. In Sec.  17.95, amend paragraph (c) by adding entries for ``Northern 
Mexican Gartersnake (Thamnophis eques megalops)'' and ``Narrow-headed 
Gartersnake (Thamnophis rufipunctatus),'' in the same alphabetical 
order that the species appear in the table at Sec.  17.11(h), to read 
as follows:


Sec.  17.95  Critical habitat--fish and wildlife.

* * * * *
    (c) Reptiles.
* * * * *
Northern Mexican Gartersnake (Thamnophis eques megalops)
    (1) Critical habitat units are depicted for Greenlee, Graham, 
Apache, La Paz, Mohave, Yavapai, Navajo, Gila, Coconino, Cochise, Santa 
Cruz, Pima, and Pinal Counties in Arizona, as well as in Grant, 
Hidalgo, and Catron Counties in New Mexico, on the maps below.
    (2) Within these areas, the primary constituent elements of the 
physical or biological features essential to the conservation of the 
northern Mexican gartersnake consist of:
    (i) Aquatic or riparian habitat that includes:
    (A) Perennial or spatially intermittent streams of low to moderate 
gradient that possess appropriate amounts of in-channel pools, off-
channel pools, or backwater habitat, and that possess a natural, 
unregulated flow regime that allows for periodic flooding or, if flows 
are modified or regulated, a flow regime that allows for adequate river 
functions, such as flows capable of processing sediment loads; or
    (B) Lentic wetlands such as livestock tanks, springs, and cienegas; 
and
    (C) Shoreline habitat with adequate organic and inorganic 
structural complexity to allow for thermoregulation, gestation, 
shelter, protection from predators, and foraging opportunities (e.g., 
boulders, rocks, organic debris such as downed trees or logs, debris 
jams, small mammal burrows, or leaf litter); and
    (D) Aquatic habitat with characteristics that support a native 
amphibian prey base, such as salinities less than 5 parts per thousand, 
pH greater than or equal to 5.6, and pollutants absent or minimally 
present at levels that do not affect survival of any age class of the 
northern Mexican gartersnake or the maintenance of prey populations.
    (ii) Adequate terrestrial space (600 ft (182.9 m) lateral extent to 
either side of bankfull stage) adjacent to designated stream systems 
with sufficient structural characteristics to support life-history 
functions such as gestation, immigration, emigration, and brumation.
    (iii) A prey base consisting of viable populations of native 
amphibian and native fish species.
    (iv) An absence of nonnative fish species of the families 
Centrarchidae and Ictaluridae, bullfrogs (Lithobates catesbeianus), 
and/or crayfish (Orconectes virilis, Procambarus clarki, etc.), or 
occurrence of these nonnative

[[Page 41585]]

species at low enough levels such that recruitment of northern Mexican 
gartersnakes and maintenance of viable native fish or soft-rayed 
nonnative fish populations (prey) is still occurring.
    (3) Critical habitat does not include manmade structures (such as 
buildings, aqueducts, runways, roads, and other paved areas) and the 
land on which they are located existing within the legal boundaries on 
the effective date of this rule.
    (4) Critical habitat map units. Data layers defining map units were 
created on a base of USGS 7.5' quadrangles, the Service's online Lands 
Mapper, the U.S. Geological Survey National Hydrography Dataset, and 
imagery from Google Earth. Line locations for lotic streams (flowing 
water) and drainages are depicted as the ``Flowline'' feature class 
from the National Hydrography Dataset geodatabase. Administrative 
boundaries for Arizona and New Mexico were obtained from the Arizona 
Land Resource Information Service and New Mexico Resource Geographic 
Information System, respectively. This includes the most current (as of 
the effective date of this rule) geospatial data available for land 
ownership, counties, States, and streets. Locations depicting critical 
habitat are expressed as decimal degree latitude and longitude in the 
World Geographic Coordinate System projection using the 1984 datum 
(WGS84). Information on northern Mexican gartersnake localities was 
derived from survey forms, reports, publications, field notes, and 
other sources, all of which reside in our files at the Arizona 
Ecological Services Field Office, 2321 West Royal Palm Road, Suite 103, 
Phoenix, AZ 85021.
BILLING CODE 4310-55-P

[[Page 41586]]

    (5) Index map follows:
    [GRAPHIC] [TIFF OMITTED] TP10JY13.006
    

[[Page 41587]]


    (6) Upper Gila River Unit: Hidalgo and Grant Counties, NM; Graham 
County, AZ. Map of the Upper Gila River Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.007


[[Page 41588]]


    (7) Mule Creek Unit: Catron and Grant Counties, NM. Map of the Mule 
Creek Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.008


[[Page 41589]]


    (8) Bill Williams River Unit: La Paz and Mohave Counties, AZ. Map 
of the Bill Williams River Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.009


[[Page 41590]]


    (9) Agua Fria River Subbasin Unit: Yavapai County, AZ. Map of the 
Agua Fria River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.010


[[Page 41591]]


    (10) Upper Salt River Subbasin Unit: Gila, Graham, Apache, Navajo, 
and Greenlee Counties, AZ. Map of the Upper Salt River Subbasin Unit 
follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.011


[[Page 41592]]


    (11) Tonto Creek Unit: Gila County, AZ. Map of the Tonto Creek Unit 
follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.012


[[Page 41593]]


    (12) Verde River Subbasin Unit: Coconino, Gila, and Yavapai 
Counties, AZ. Map of the Verde River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.013


[[Page 41594]]


    (13) Upper Santa Cruz River Subbasin Unit: Santa Cruz and Cochise 
Counties, AZ. Map of the Upper Santa Cruz River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.014


[[Page 41595]]


    (14) Redrock Canyon Unit: Santa Cruz County, AZ. Map of the Redrock 
Canyon Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.015


[[Page 41596]]


    (15) Buenos Aires National Wildlife Refuge Unit: Pima County, AZ. 
Map of the Buenos Aires National Wildlife Refuge Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.016


[[Page 41597]]


    (16) Cienega Creek Subbasin Unit: Pima and Santa Cruz Counties, AZ. 
Map of the Cienega Creek Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.017


[[Page 41598]]


    (17) San Pedro River Subbasin Unit: Cochise, Pima, and Pinal 
Counties, AZ. Map of the San Pedro River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.018


[[Page 41599]]


    (18) Babocomari River Subbasin Unit: Santa Cruz and Cochise 
Counties, AZ. Map of the Babocomari River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.019


[[Page 41600]]


    (19) San Bernardino National Wildlife Refuge Unit: Cochise County, 
AZ. Map of the San Bernardino National Wildlife Refuge Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.020

BILLING CODE 4310-55-C
Narrow-Headed Gartersnake (Thamnophis rufipunctatus)
    (1) Critical habitat units are depicted for Greenlee, Graham, 
Apache, Yavapai, Navajo, Gila, and Coconino Counties in Arizona, as 
well as in Grant, Hidalgo, Sierra, and Catron Counties in New Mexico, 
on the maps below.
    (2) Within these areas, the primary constituent elements of the 
physical or biological features essential to the conservation of the 
narrow-headed gartersnake consist of four components:
    (i) Stream habitat, which includes:
    (A) Perennial or spatially intermittent streams with sand, cobble, 
and boulder substrate and low or moderate amounts of fine sediment and 
substrate embeddedness, and that possess appropriate amounts of pool, 
riffle, and

[[Page 41601]]

run habitat to sustain native fish populations;
    (B) A natural, unregulated flow regime that allows for periodic 
flooding or, if flows are modified or regulated, a flow regime that 
allows for adequate river functions, such as flows capable of 
processing sediment loads;
    (C) Shoreline habitat with adequate organic and inorganic 
structural complexity (e.g., boulders, cobble bars, vegetation, and 
organic debris such as downed trees or logs, debris jams), with 
appropriate amounts of shrub- and sapling-sized plants to allow for 
thermoregulation, gestation, shelter, protection from predators, and 
foraging opportunities; and
    (D) Aquatic habitat with no pollutants or, if pollutants are 
present, levels that do not affect survival of any age class of the 
narrow-headed gartersnake or the maintenance of prey populations.
    (ii) Adequate terrestrial space (600 ft (182.9 m) lateral extent to 
either side of bankfull stage) adjacent to designated stream systems 
with sufficient structural characteristics to support life-history 
functions such as gestation, immigration, emigration, and brumation.
    (iii) A prey base consisting of viable populations of native fish 
species or soft-rayed nonnative fish species.
    (iv) An absence of nonnative fish species of the families 
Centrarchidae and Ictaluridae, bullfrogs (Lithobates catesbeianus), 
and/or crayfish (Orconectes virilis, Procambarus clarki, etc.), or 
occurrence of these nonnative species at low enough levels such that 
recruitment of narrow-headed gartersnakes and maintenance of viable 
native fish or soft-rayed nonnative fish populations (prey) is still 
occurring.
    (3) Critical habitat does not include manmade structures (such as 
buildings, aqueducts, runways, roads, and other paved areas) and the 
land on which they are located existing within the legal boundaries on 
the effective date of this rule.
    (4) Critical habitat map units. Data layers defining map units were 
created on a base of USGS 7.5' quadrangles, the Service's online Lands 
Mapper, the U.S. Geological Survey National Hydrography Dataset, and 
imagery from Google Earth. Line locations for lotic streams (flowing 
water) and drainages are depicted as the ``Flowline'' feature class 
from the National Hydrography Dataset geodatabase. Administrative 
boundaries for Arizona and New Mexico were obtained from the Arizona 
Land Resource Information Service and New Mexico Resource Geographic 
Information System, respectively. This includes the most current (as of 
the effective date of this rule) geospatial data available for land 
ownership, counties, States, and streets. Locations depicting critical 
habitat are expressed as decimal degree latitude and longitude in the 
World Geographic Coordinate System projection using the 1984 datum 
(WGS84). Information on narrow-headed gartersnake localities was 
derived from survey forms, reports, publications, field notes, and 
other sources, all of which reside in our files at the Arizona 
Ecological Services Field Office, 2321 West Royal Palm Road, Suite 103, 
Phoenix, AZ 85021.

[[Page 41602]]

    (5) Index map follows:
BILLING CODE 4310-55-P
[GRAPHIC] [TIFF OMITTED] TP10JY13.021


[[Page 41603]]


    (6) Upper Gila River Subbasin Unit: Catron and Grant Counties, NM; 
Graham County, AZ. Map of the Upper Gila River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.022


[[Page 41604]]


    (7) Middle Gila River Subbasin Unit: Greenlee and Graham Counties, 
AZ. Map of the Middle Gila River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.023


[[Page 41605]]


    (8) San Francisco River Subbasin Unit: Greenlee County, AZ; Catron 
County, NM. Map of the San Francisco River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.024


[[Page 41606]]


    (9) Upper Salt River Subbasin Unit: Gila, Graham, Apache, Navajo, 
Greenlee, and Coconino Counties, AZ. Map of the Upper Salt River 
Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.025


[[Page 41607]]


    (10) Tonto Creek Subbasin Unit: Gila County, AZ. Map of the Tonto 
Creek Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.026


[[Page 41608]]


    (11) Verde River Subbasin Unit: Coconino, Gila, and Yavapai 
Counties, AZ. Map of the Verde River Subbasin Unit follows:
[GRAPHIC] [TIFF OMITTED] TP10JY13.027

* * * * *

    Dated: June 25, 2013.
Rachel Jacobsen,
Principal Deputy Assistant Secretary for Fish and Wildlife and Parks.
[FR Doc. 2013-16520 Filed 7-9-13; 8:45 am]
BILLING CODE 4310-55-C