[Federal Register Volume 85, Number 82 (Tuesday, April 28, 2020)]
[Proposed Rules]
[Pages 23608-23668]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-08069]



[[Page 23607]]

Vol. 85

Tuesday,

No. 82

April 28, 2020

Part II





Department of the Interior





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





Fish and Wildlife Service





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





50 CFR 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. 85 , No. 82 / Tuesday, April 28, 2020 / 
Proposed Rules  

[[Page 23608]]


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

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2020-0011; FF09E21000 FXES11110900000 201]
RIN 1018-BD96


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: Revised proposed rule; request for public comments.

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

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are revising 
our proposed designation of critical habitat for the northern Mexican 
gartersnake (Thamnophis eques megalops) and narrow-headed gartersnake 
(Thamnophis rufipunctatus) under the Endangered Species Act, as amended 
(Act). In total, approximately 27,784 acres (11,244 hectares) in La 
Paz, Mohave, Yavapai, Gila, Cochise, Santa Cruz, and Pima Counties in 
Arizona, and in Grant County in New Mexico, fall within the boundaries 
of the revised proposed critical habitat designation for the northern 
Mexican gartersnake; and 18,701 acres (7,568 hectares) in Greenlee, 
Graham, Apache, Yavapai, Gila, and Coconino Counties in Arizona, as 
well as in Grant, Hidalgo, and Catron Counties in New Mexico, fall 
within the boundaries of the revised proposed critical habitat 
designation for the narrow-headed gartersnake. We also announce the 
availability of a draft economic analysis of the revised proposed 
designation of critical habitat for northern Mexican and narrow-headed 
gartersnakes. We request comments from all interested parties on this 
revised proposed rule and the associated draft economic analysis. 
Comments submitted on our July 10, 2013, proposed rule need not be 
resubmitted as they will be fully considered in the preparation of the 
final rule. If we finalize this rule as proposed, it would extend the 
Act's protections to these species' critical habitat.

DATES: We will accept comments on this revised proposed rule or the 
draft economic analysis that are received or postmarked on or before 
June 29, 2020. Comments submitted electronically using the Federal 
eRulemaking Portal (see ADDRESSES, 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 FOR FURTHER 
INFORMATION CONTACT by June 12, 2020.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal:
    http://www.regulations.gov. In the Search box, enter FWS-R2-ES-
2020-0011, which is the docket number for this rulemaking. Then, click 
on the Search button. On the resulting page, in the Search panel on the 
left side of the screen, under the Document Type heading, check the 
Proposed Rule box to locate this document. You may submit a comment by 
clicking on ``Comment Now!''
    (2) By hard copy: Submit by U.S. mail to: Public Comments 
Processing, Attn: FWS-R2-ES-2020-0011, U.S. Fish and Wildlife Service, 
MS: JAO/1N, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
    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, below, for more information).
    Availability of supporting materials: The draft economic analysis 
is available at http://www.fws.gov/southwest/es/arizona/, at http://www.regulations.gov at Docket No. FWS-R2-ES-2020-0011, and at the 
Arizona Ecological Services Field Office (see FOR FURTHER INFORMATION 
CONTACT).
    For the critical habitat designation, the coordinates or plot 
points or both from which the maps are generated are included in the 
administrative record and are available at http://www.fws.gov/southwest/es/arizona, at http://www.regulations.gov under Docket No. 
FWS-R2-ES-2020-0011 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 critical habitat 
designation will also be available at the Fish and Wildlife Service 
website and Field Office set out above, and may also be included in the 
preamble and/or at http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Jeff Humphry, Field Supervisor, U.S. 
Fish and Wildlife Service, Arizona Ecological Services Field Office, 
Fish and Wildlife Office, 9828 North 31st Ave #C3, Phoenix, AZ 85051-
2517; telephone 602-242-0210. Persons who use a telecommunications 
device for the deaf (TDD), may call the Federal Relay Service at 800-
877-8339.

SUPPLEMENTARY INFORMATION: 

Executive Summary

    Why we need to publish a rule. 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. Both gartersnakes are listed as threatened under the Act (79 FR 
38678; July 8, 2014). Designations and revisions of critical habitat 
can only be completed by issuing a rule.
    What this document does. This is a revised proposed rule to 
designate critical habitat for northern Mexican gartersnake and narrow-
headed gartersnake under the Act.
    For reasons described later in this document, this revised proposed 
rule reduces the proposed critical habitat designation from what we 
proposed on July 10, 2013, as follows:
     For the northern Mexican gartersnake, the proposed 
designation is reduced from approximately 421,423 acres (170,544 
hectares) to approximately 27,784 acres (11,244 hectares); and
     For the narrow-headed gartersnake, the proposed 
designation is reduced from approximately 210,189 acres (85,060 
hectares) to approximately 18,701 acres (7,568 hectares).
    The basis for our action. Section 4(a)(3) of the Act requires the 
Secretary of the Interior (Secretary) to designate critical habitat 
concurrent with listing to the maximum extent prudent and determinable. 
Section 4(b)(2) of the Act states that the Secretary must make the 
designation on the basis of the best scientific data available and 
after taking into consideration the economic impact, the impact on 
national security, and any other relevant impacts of specifying any 
particular area as critical habitat. Section 3(5)(A) of the Act defines 
critical habitat as (i) the specific areas within the geographical area 
occupied by the species, at the time it is listed, on which are found 
those physical or biological features (I) essential to the conservation 
of the species and (II) which may require special management 
considerations or protections; and (ii) specific areas outside the 
geographical area occupied by the species at the time it is listed, 
upon a determination by the Secretary that such areas are essential for 
the conservation of the species.
    Peer review. In accordance with our joint policy on peer review 
published in the Federal Register on July 1, 1994 (59 FR 34270), and 
our August 22, 2016, memorandum updating and clarifying

[[Page 23609]]

the role of peer review of listing actions under the Act, we sought the 
expert opinions of eight independent specialists on the July 10, 2013, 
proposed rule to ensure that our critical habitat proposal was based on 
scientifically sound data, assumptions, and analyses. We received 
responses from three of the peer reviewers. We reviewed all comments we 
received from the peer reviewers for substantive issues and new 
information regarding critical habitat for the two gartersnakes. Peer 
reviewers substantive comments have been addressed or incorporated into 
this revised proposed rule. Because we will consider all comments and 
information we receive during the comment period, our final 
determinations may differ from this proposal. Such final decisions 
would be a logical outgrowth of this proposal, as long as we: (1) Base 
the decisions on the best scientific and commercial data available 
after considering all of the relevant factors; (2) do not rely on 
factors Congress has not intended us to consider; and (3) articulate a 
rational connection between the facts found and the conclusions made, 
including why we changed our conclusion.

Information Requested

    We intend that any final action resulting from this revised 
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 government 
agencies, Native American tribes, the scientific community, industry, 
or any other interested party concerning this revised 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 information to inform the following factors that the 
regulations identify as reasons why designation of critical habitat may 
be not prudent:
    (a) The species is threatened by taking, collecting, or other human 
activity and identification of critical habitat can be expected to 
increase the degree of such threat to the species;
    (b) The present or threatened destruction, modification, or 
curtailment of a species' habitat or range is not a threat to the 
species, or threats to the species' habitat stem solely from causes 
that cannot be addressed through management actions resulting from 
consultations under section 7(a)(2) of the Act;
    (c) Areas within the jurisdiction of the United States provide no 
more than negligible conservation value, if any, for a species 
occurring primarily outside the jurisdiction of the United States; or
    (d) No areas meet the definition of critical habitat.
    (2) Specific information on:
    (a) The amount and distribution of northern Mexican or narrow-
headed gartersnake habitat;
    (b) Which areas, that were occupied at the time of listing (2013) 
and that contain the physical or biological features essential to the 
conservation of these species, should be included in the designation 
and why;
    (c) What period of time should be used to ascertain occupancy at 
time of listing (2013) and why, and whether or not data from 1998 to 
the present should be used in this determination;
    (d) Whether it is appropriate to use information from a long-term 
dispersal study on neonate, juvenile, and adult age classes of the 
Oregon gartersnake (Thamnophis atratus hydrophilus) in a free-flowing 
stream environment in northern California (Welsh et al. 2010, entire) 
as a surrogate for juvenile northern Mexican gartersnake and narrow-
headed gartersnake dispersal;
    (e) Special management considerations or protection that may be 
needed in critical habitat areas we are proposing, including managing 
for the potential effects of climate change; and
    (f) What areas not occupied at the time of listing are essential 
for the conservation of these species and why. We particularly seek 
comments regarding:
    (i) Whether occupied areas are inadequate for the conservation of 
the species; and
    (ii) Specific information that informs the determination of whether 
unoccupied areas will, with reasonable certainty, contribute to the 
conservation of the species and contain at least one physical or 
biological feature essential to the conservation of the species.
    (3) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat.
    (4) Information on the projected and reasonably likely impacts of 
climate change on the northern Mexican or narrow-headed gartersnake and 
proposed critical habitat.
    (5) Any probable economic, national security, or other relevant 
impacts of designating any area that may be included in the final 
designation, and the benefits of including or excluding areas that may 
be impacted.
    (6) Information on the extent to which the description of probable 
economic impacts in the draft economic analysis is a reasonable 
estimate of the likely economic impacts.
    (7) Whether any specific areas we are proposing for critical 
habitat designation should be considered for exclusion under section 
4(b)(2) of the Act, and whether the benefits of potentially excluding 
any specific area outweigh the benefits of including that area under 
section 4(b)(2) of the Act, in particular for those lands discussed in 
each critical habitat unit and in tables 3a and 3b, below.
    (8) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate public concerns and 
comments.
    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 a 
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 ADDRESSES. We request that you 
send comments only by the methods described in ADDRESSES.
    If you submit information via http://www.regulations.gov, your 
entire submission--including any personal identifying information--will 
be posted on the website. 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).

[[Page 23610]]

Public Hearing

    Section 4(b)(5) of the Act provides for a public hearing 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 
(see DATES, above). Such requests must be sent to the address shown in 
FOR FURTHER INFORMATION CONTACT. We will schedule a public hearing on 
this proposal, if requested, and announce the date, time, and place of 
the hearing, as well as how to obtain reasonable accommodations, in the 
Federal Register and local newspapers at least 15 days before the 
hearing. For the immediate future, we will provide these public 
hearings using webinars that will be announced on the Service's 
website, in addition to the Federal Register. The use of these virtual 
public hearings is consistent with our regulation at 50 CFR 
424.16(c)(3).

Previous Federal Actions

    On July 10, 2013, we published in the Federal Register (78 FR 
41550) a proposed rule to designate critical habitat for northern 
Mexican gartersnake and narrow-headed gartersnake. In that proposed 
rule, we proposed to designate approximately 421,423 acres (ac) 
(170,544 hectares (ha)) as critical habitat in 14 units for the 
northern Mexican gartersnake and 210,189 ac (85,060 ha) as critical 
habitat in 6 units for the narrow-headed gartersnake. That proposal had 
a 60-day comment period, ending September 9, 2013. We received 
substantive comments during the comment period that have contributed to 
the current revised proposed rule.

Background

    It is our intent to discuss in this document only those topics 
directly relevant to the designation of critical habitat for northern 
Mexican gartersnake and narrow-headed gartersnake. For more information 
on the two species, their corresponding habitats, and previous Federal 
actions concerning the two species, refer to the proposed designation 
of critical habitat published in the Federal Register on July 10, 2013 
(78 FR 41550). The proposed rule is available online at http://www.regulations.gov (at Docket No. FWS-R2-ES-2020-0011) or from the 
Arizona Ecological Services Field Office (see FOR FURTHER INFORMATION 
CONTACT).
    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.
    Our regulations at 50 CFR 424.02 define the geographical area 
occupied by the species as an area that may generally be delineated 
around species' occurrences, as determined by the Secretary of the 
Interior (i.e., range). Such areas may include those areas used 
throughout all or part of the species' life cycle, even if not used on 
a regular basis (e.g., migratory corridors, seasonal habitats, and 
habitats used periodically, but not solely by vagrant individuals).
    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. Designation also does not allow the government 
or public to access private lands, nor does designation 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 Federal agency would be required to consult 
with the Service under section 7(a)(2) of the Act. However, even if the 
Service were to conclude that the proposed activity would result in 
destruction or adverse modification of the critical habitat, the 
Federal action agency and the landowner are not required to abandon the 
proposed activity, or to restore or recover the species; instead, they 
must 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 geographical 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 or biological features that occur in specific occupied areas, 
we focus on the specific features that are essential to support the 
life-history needs of the species, including, but not limited to, water 
characteristics, soil type, geological features, prey, vegetation, 
symbiotic species, or other features. A feature may be a single habitat 
characteristic, or a more complex combination of habitat 
characteristics. Features may include habitat characteristics that 
support ephemeral or dynamic habitat conditions. Features may also be 
expressed in terms relating to principles of conservation biology, such 
as patch size, distribution distances, and connectivity.
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in 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. When designating critical habitat, the Secretary will first 
evaluate areas occupied by the species. The Secretary will only 
consider unoccupied areas to be essential where a critical habitat 
designation limited to geographical areas occupied by the species would 
be inadequate to ensure the conservation of the species. In addition, 
for an unoccupied area to be considered essential, the Secretary must 
determine that there is a reasonable certainty both that the area will 
contribute to the conservation of the

[[Page 23611]]

species and that the area contains one or more of those physical or 
biological features essential to 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 any generalized conservation 
strategy, criteria, or outline that may have been developed for the 
species; 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 continue to 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 Act's prohibitions on taking any individual of the 
species, including taking caused by actions that affect habitat. 
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 Secretary 
may, but is not required to, determine that a designation would not be 
prudent in the following circumstances:
    (i) The species is threatened by taking or other human activity and 
identification of critical habitat can be expected to increase the 
degree of such threat to the species;
    (ii) The present or threatened destruction, modification, or 
curtailment of a species' habitat or range is not a threat to the 
species, or threats to the species' habitat stem solely from causes 
that cannot be addressed through management actions resulting from 
consultations under section 7(a)(2) of the Act;
    (iii) Areas within the jurisdiction of the United States provide no 
more than negligible conservation value, if any, for a species 
occurring primarily outside the jurisdiction of the United States;
    (iv) No areas meet the definition of critical habitat; or
    (v) The Secretary otherwise determines that designation of critical 
habitat would not be prudent based on the best scientific data 
available.
    As discussed in the final listing rule published on July 8, 2014 
(79 FR 38678), there is currently no imminent threat of take attributed 
to collection or vandalism identified under Factor B for these species, 
and identification and mapping of critical habitat is not expected to 
initiate any such threat. In our proposed listing rule for the northern 
Mexican gartersnake and narrow-headed gartersnake (78 FR 41500; July 
10, 2013), we determined that the present or threatened destruction, 
modification, or curtailment of habitat or range is a threat to these 
species and that those threats in some way can be addressed by section 
7(a)(2) consultation measures. The species occurs wholly in the 
jurisdiction of the United States, and we are able to identify areas 
that meet the definition of critical habitat. Therefore, because none 
of the circumstances enumerated in our regulations at 50 CFR 
424.12(a)(1) has been met and because there are no other circumstances 
the Secretary has identified for which this designation of critical 
habitat would be not prudent, we have determined that the designation 
of critical habitat is prudent for these species.

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 
Mexican gartersnake and narrow-headed gartersnake 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) Data sufficient to perform required analyses are lacking, or
    (ii) The biological needs of the species are not sufficiently well 
known to identify any area that meets the definition of ``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 available information pertaining to the biological 
needs of these species and habitat characteristics where these species 
are located. This and other information represent the best scientific 
and commercial data available and led us to conclude that the 
designation of critical habitat is determinable for the Mexican 
gartersnake and narrow-headed gartersnake.

Changes From Previously Proposed Critical Habitat

    In this document, we are revising our proposed critical habitat 
designations for the northern Mexican gartersnake and narrow-headed 
gartersnake (78 FR 41550; July 10, 2013). We based these revisions on 
information we received during the comment period on the July 10, 2013, 
proposed rule, as well as on relevant scientific research conducted 
after the publication of that proposed rule. After the publication of 
the proposed rule, we found that there was

[[Page 23612]]

substantial scientific disagreement in the criteria we used to define 
what areas were occupied at the time of listing for each species, and 
the criteria we used to identify the lateral extent of critical habitat 
boundaries. We also received additional information including locations 
of each species at the time of listing, and the biological needs and 
corresponding habitat characteristics of each species. We also note 
that we no longer use primary constituent elements (PCEs) to identify 
areas as critical habitat. The Service eliminated primary constituent 
elements due to redundancy with the physical or biological features 
(PBFs). This change in terminology is in accordance with a February 11, 
2016 (81 FR 7414), rule to implement changes to the regulations for 
designating critical habitat. We used the comments and additional 
information to revise: (1) The PBFs that are essential to the 
conservation of the species and which may require special management 
considerations or protection under the Act, (2) the criteria used to 
define the areas occupied at the time of listing for each species, and 
(3) the criteria used to identify critical habitat boundaries. We then 
apply the revised PBFs and identification criteria for each gartersnake 
species along with additional information we received regarding where 
these PBFs exist on the landscape to determine the geographic extent of 
each critical habitat unit. Finally, we provide clarification of some 
of the terms we used to define critical habitat for each species.

Primary Constituent Elements

Background
    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12(b), in determining which areas we will designate as 
critical habitat from within the geographical area occupied by the 
species at the time of listing, we consider the physical or biological 
features that are essential to the conservation of the species and that 
may require special management considerations or protection. The 
regulations at 50 CFR 424.02 define ``physical or biological features 
essential to the conservation of the species'' as the features that 
occur in specific areas and that are essential to support the life-
history needs of the species, including, but not limited to, water 
characteristics, soil type, geological features, sites, prey, 
vegetation, symbiotic species, or other features. A feature may be a 
single habitat characteristic or a more complex combination of habitat 
characteristics. Features may include habitat characteristics that 
support ephemeral or dynamic habitat conditions. Features may also be 
expressed in terms relating to principles of conservation biology, such 
as patch size, distribution distances, and connectivity. For example, 
physical features essential to the conservation of the species might 
include gravel of a particular size required for spawning, alkali soil 
for seed germination, protective cover for migration, or susceptibility 
to flooding or fire that maintains necessary early-successional habitat 
characteristics. Biological features might include prey species, forage 
grasses, specific kinds or ages of trees for roosting or nesting, 
symbiotic fungi, or a particular level of nonnative species consistent 
with conservation needs of the listed species. The features may also be 
combinations of habitat characteristics and may encompass the 
relationship between characteristics or the necessary amount of a 
characteristic essential to support the life history of the species.
    In considering whether features are essential to the conservation 
of the species, the Service may consider an appropriate quality, 
quantity, and spatial and temporal arrangement of habitat 
characteristics in the context of the life-history needs, condition, 
and status of the species. These characteristics include, but are not 
limited to, space for individual and population growth and for normal 
behavior; food, water, air, light, minerals, or other nutritional or 
physiological requirements; cover or shelter; sites for breeding, 
reproduction, or rearing (or development) of offspring; and habitats 
that are protected from disturbance.
Previous Proposed Rule's Primary Constituent Elements
    As stated above, we now use only PBFs that are essential to the 
conservation of the species to describe critical habitat. We have 
modified the PCEs from the previous critical habitat rule, which are 
now PBFs in this rule. For your convenience, we are providing the PCEs 
from the previous proposed critical habitat rule for you to compare the 
changes.
    The northern Mexican gartersnake's previous PCEs were:
    (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 natural 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 feet (ft) (182.9 meter (m)) 
lateral extent to either side of bankfull stage) adjacent to designated 
stream systems with sufficient natural 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.
    The narrow-headed gartersnake's previous PCEs were:
    (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 natural 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

[[Page 23613]]

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 natural 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.
Stream Flow
    In the July 10, 2013, proposed rule (78 FR 41550) under PCE 1 for 
each species we use the terms ``perennial'' and ``spatially 
intermittent,'' but we did not include a definition of perennial or 
spatially intermittent flow.
    In this revised proposed rule, we are defining the terms perennial, 
spatially intermittent, and ephemeral as related to stream flow in PBF 
1 for each gartersnake species. We are clarifying the spectrum of 
stream flow regimes that provide stream habitat for each gartersnake 
species based on stream flow definitions in Levick et al. (2008, p. 6) 
and Stromberg et al. (2009, p. 330). A perennial stream or portion of a 
stream is defined as having surface flow continuously year round, 
except for infrequent periods of severe drought (Levick et al. 2008, p. 
6). An intermittent stream is a stream where portions flow continuously 
only at certain time of the year (Levick et al. 2008, p. 6). An 
intermittent stream flows when it receives water from a spring, a 
ground-water source, or a surface source (such as melting snow [i.e., 
seasonal]). During the dry seasons, frequently compounded by high 
evapotranspiration of watershed vegetation, the ground water table may 
drop below the elevation of the streambed, causing surface flow to 
cease or reduce to a series of separate pools or short areas of flow 
(Gordon et al. 2004, p. 51). An ephemeral stream is usually dry except 
for brief periods immediately following precipitation, and its channel 
is at all times above the groundwater table (Levick et al. 2008, p. 6). 
In the range of each gartersnake species, many streams have reaches 
with year-round water that are separated by intermittent or ephemeral 
reaches of flow, as a result of differences in geology along the 
stream. This variation of flow along a stream is common enough in the 
Southwest that hydrologists use the terms ``interrupted,'' ``perennial 
interrupted,'' or ``spatially intermittent'' to describe the spatial 
segmentation of a dryland stream into reaches that are perennial, 
intermittent, or ephemeral (Levick et al. 2008, p. 6; Stromberg et al. 
2009, p. 330; Stromberg et al. 2013, p. 413). A stream that is 
interrupted, perennially interrupted, or spatially intermittent has 
perennial flow occurring in areas with shallow bedrock or high 
hydraulic connectivity to regional aquifers, and ephemeral to 
intermittent flow occurring in areas with deeper alluvial basins or 
greater distance from the headwaters (Stromberg et al. 2009, p. 330). 
The spatial patterning of wet and dry reaches on spatially intermittent 
streams changes through time in response to climatic fluctuations and 
to human modifications of the landscape (Stromberg et al. 2009, p. 
331). In the remainder of this document, we use the terms 
``perennial,'' ``spatially intermittent,'' and ``ephemeral'' in 
accordance with the above definitions.
    For northern Mexican gartersnake, streams that have perennial or 
spatially intermittent flow can provide stream habitat for the species. 
Ephemeral reaches of streams can serve as habitat for northern Mexican 
gartersnakes, and are included in critical habitat as a separate PBF 
(#7) if such reaches are between perennial sections of a stream that 
were occupied at the time of listing. Streams that have ephemeral flow 
over their entire length do not usually provide habitat for the 
northern Mexican gartersnake, but are considered critical habitat when 
they may serve as corridors between perennial streams and lentic 
aquatic habitats including springs, cienegas, and natural or 
constructed ponds (livestock tanks) that were occupied at the time of 
listing.
    For narrow-headed gartersnake, streams that have perennial flow or 
limited spatially intermittent flow that is primarily perennial provide 
stream habitat for the species. Narrow-headed gartersnakes have been 
documented in pools and shallow portions of an intermittent flow reach 
of the Blue River with wet areas separated by dry segments of 0.6 to 
1.2 miles (1 to 2 kilometers (km)) in length (Cotten et al. 2017, p. 
687). The wetted areas where gartersnakes were detected also had 
abundant native prey of the narrow-headed gartersnake, indicating that 
these areas may provide greater foraging opportunities during low flow 
periods (Cotten et al. 2017, p. 687). However, ephemeral reaches of 
streams do not provide habitat for narrow-headed gartersnakes. Within 
the range of the narrow-headed gartersnake, perennial streams become 
ephemeral as they approach their headwaters. However, narrow-headed 
gartersnakes have not been found in these ephemeral reaches because 
their fish prey base is likely absent and there is no upstream 
perennial habitat, so the ephemeral reaches do not provide 
connectivity.
Hydrologic Processes
    In the previous proposed critical habitat rule, hydrologic 
processes of a stream were captured in PCE 1 as part of a component of 
aquatic habitat: ``[aquatic habitat that possesses] 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.'' These 
processes are not the aquatic habitat or terrestrial habitat components 
themselves, but the flow regime and physical hydrologic and geomorphic 
connection that create and maintain a stream channel and continuously 
redefine the boundary between aquatic and riparian habitat used by both 
gartersnake species.
    Both gartersnake species are dependent on terrestrial and aquatic 
habitat for all of their life-history functions, so it is important 
that hydrologic processes are present to maintain both the terrestrial 
and aquatic components of habitat for both gartersnake species. 
Therefore, we established a PBF (#2) for hydrological processes that is 
separate from the aquatic and terrestrial habitat PBF (#1).
Lentic Wetlands
    For northern Mexican gartersnake, we removed lentic wetlands 
included in PCE 1 of the previous proposed rule and created a separate 
PBF (#6) that includes the aquatic and terrestrial components of these 
habitats.
Shoreline Habitat
    In the previous proposed rule, shoreline habitat is included in PCE 
1. For northern Mexican gartersnake, PCE 1 was ``aquatic or riparian 
habitat'' and for the narrow-headed gartersnake it was ``stream 
habitat.'' For both gartersnakes, we defined shoreline

[[Page 23614]]

habitat as areas having ``adequate organic and inorganic structural 
complexity'' with examples such as boulders, rocks, and organic debris 
for thermoregulation, gestation, shelter, protection from predators, 
and foraging opportunities.
    In this revised proposed rule, we are no longer including the term 
``shoreline habitat,'' because shorelines fluctuate and can include 
both terrestrial and aquatic habitat features used by either 
gartersnake species. Instead, a component of PBF 1 focuses on the 
organic and natural inorganic structural features important to each 
gartersnake species that fall within the stream channel that 
encompasses a fluctuating shoreline.
Water Quality
    In the July 10, 2013, proposed rule, for the northern Mexican 
gartersnake under PCE 1, we state: ``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'' (78 FR 41550, July 10, 2013, p. 
78 FR 41584). In that proposed rule, for the narrow-headed gartersnake 
under PCE 1, we state: ``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'' (78 FR 41550, July 10, 2013, p. 78 FR 41601).
    In this revised proposed rule, we are removing the specific 
salinity and pH requirement for habitat characteristics that support a 
native amphibian prey base for the northern Mexican gartersnake. As 
mentioned in the July 10, 2013, proposed rule, while native leopard 
frogs can be the primary prey base for adult northern Mexican 
gartersnakes in some areas, these gartersnakes feed on a variety of 
organisms that do not necessarily require the salinity and pH specified 
in the PCE (78 FR 41550, July 10, 2013, pp. 78 FR 41553-41554). Because 
we do not have salinity and pH values needed for the variety of aquatic 
organisms that the different age classes of northern Mexican 
gartersnakes eat, we are making this PBF more general. We did not make 
substantive changes to the relevant PBF component for narrow-headed 
gartersnake.
Prey Base
    In the July 10, 2013, proposed rule, we described a wholly native 
prey base of amphibians and fish for the northern Mexican gartersnake 
in PCE 3, but in PCE 4, we state that nonnative fish are also prey for 
the species. In the discussion of PBFs, we noted that northern Mexican 
gartersnakes consume primarily amphibians and fishes, but that 
occasional invertebrates and other vertebrate taxa may be eaten 
opportunistically (78 FR 41550, July 10, 2013, p. 78 FR 41554) and that 
the success of northern Mexican gartersnake populations is, in some 
cases, tied to nonnative prey species consisting of larval and juvenile 
bullfrogs. We did not include these other taxa and bullfrogs in the 
PCEs because they are either relatively rare in the diet (in the case 
of invertebrates and other vertebrates) or in the case of bullfrogs, 
the adult frogs prey voraciously on gartersnake, and so despite the 
fact that the snakes eat the juveniles, the presence of bullfrogs 
indicates that the habitat is degraded.
    We received additional information regarding the prey base of 
northern Mexican gartersnake. Additional research confirms that in some 
areas where native aquatic prey species are not available, viable 
populations of northern Mexican gartersnakes likely rely on bullfrogs 
and nonnative, soft-rayed and potentially spiny-rayed fish as a primary 
food source (Emmons et al. 2016, pp. 556-557; Emmons and Nowak 2016a, 
p. 44; Emmons and Nowak 2013, pp. 6, 15; Lashway 2012, p. 7). In other 
areas where native ranid frogs are no longer present, we have 
additional information to support that northern Mexican gartersnakes 
consume other anurans (frogs and toads), small mammals, lizards, and 
invertebrate species (Caldwell 2014, p. 1; d'Orgeix et al. 2013, p. 
214; Emmons and Nowak 2016b, p. 9; Manjarriez et al. 2017, table 1).
    In this revised proposed rule, for northern Mexican gartersnake, we 
are removing the requirement for a wholly native prey base and 
including the additional prey species described above in PBF 3. We also 
used ``anurans'' (frogs and toads) instead of ``amphibians'' to more 
accurately describe the gartersnake's primary prey. We do not make 
substantive changes to PBF 3 for narrow-headed gartersnake.

Primary Constituent Elements/Critical Habitat Boundaries

Terrestrial Space Along Streams
    In the previous proposed rule, PCE 2 for both gartersnakes included 
``[a]dequate 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]'' (78 FR 41550, July 10, 2013, pp. 78 FR 41584 
and 78 FR 41601). In the discussion of the PBFs and PCEs, we stated 
that the northern Mexican gartersnake has been found up to 330 ft (100 
m) away from permanent water (Rosen and Schwalbe 1988, p. 27), and the 
narrow-headed gartersnake has been found up to 650 ft (200 m) from 
water (Nowak 2006, pp. 19-21; 78 FR 41550, July 10, 2013, p. 78 FR 
41557). We then state that ``[b]ased 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'' and that ``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'' (78 FR 41550, July 10, 2013, p. 78 
FR 41557). We go on to say that we determined 600-ft (182.9-m) lateral 
extent from bankfull width for four biological reasons, including 
maintaining the biological integrity and natural dynamics of the river 
system and associated riparian habitat, nutrient recharge, general 
aquatic habitat values, and providing adequate space for normal 
gartersnake behaviors.
    We received numerous comments and additional scientific information 
regarding our definition of adequate terrestrial space for the two 
gartersnakes in two general categories. First, using a single distance 
of 600 ft (182.9 m) lateral extent from bankfull stage for both 
gartersnake species includes areas outside the area typically used by 
each gartersnake species and can include areas that do not have any of 
the PBFs essential to the conservation of each species, especially in 
higher order streams (Nowak 2006, pp. 19-20; Jennings and Christman 
2012, pp. 8-12; Emmons and Nowak 2016a, p. 30; Myrand et al. 2017 p. 
36). Second, using ``bankfull width'' as a measurement point for the 
lateral extent of critical habitat is difficult to determine on the 
ground as evidenced by our lack of mapping it as such in the July 10, 
2013, proposed rule. Instead, we mapped critical habitat as a 1,200-ft 
(366-m) polygon surrounding the centerline of a stream (78 FR 41550, 
July 10, 2013, pp. 78 FR 41585, 78 FR 41601). We discuss both issues 
below.
    At the time of the publication of the July 10, 2013, proposed rule, 
most of the

[[Page 23615]]

information we had on locations of both gartersnake species was from 
studies where traps were set within water to capture gartersnakes and 
then gartersnakes were subsequently released. This survey method does 
not provide information on how these species use terrestrial habitat. 
Nowak et al. (2006, entire), the study we referenced in our July 10, 
2013, proposed rule, was the first study that used radio-telemetered 
narrow-headed gartersnakes to look at habitat use. This study only 
reported an individual narrow-headed gartersnake moving in a straight-
line distance of 650 ft (200 m) from water location, which we used to 
inform lateral extent of critical habitat for both gartersnake species 
because this was the best available information. However, since the 
publication of the 2013 proposed rule, E. Nowak (2015) provided the 
Service a correct interpretation of her telemetry data for this 
individual and for the other narrow-headed gartersnakes recorded in 
this study. Nowak clarified that the narrow-headed gartersnake was 
found on a steep slope approximately 390 ft (150 m) above a stream in a 
narrow canyon in a brumation site (Nowak 2006, p. 17). Nowak further 
clarified that other narrow-headed gartersnakes were recorded using 
brumation sites on the steep slope, reporting horizontal distances from 
brumation sites to stream centerline between 276 and 328 ft (84 and 100 
m). Nowak (2006, pp. 19-20) also reported at least five other 
individual narrow-headed gartersnakes overwintering at brumation sites 
not on steep slopes at 66 to 98 ft (20 to 30 m) from water. The 
important difference in the distance from the stream is dependent on 
the adjacent terrestrial topography. If the topography is steep slopes, 
then the gartersnake is found farther from the stream, but this 
additional distance is vertical, not horizontal, from the stream bank.
    Since we published the 2013 proposed rule, researchers have 
completed additional telemetry studies for each gartersnake species 
that provide information on how each gartersnake species uses 
terrestrial habitat (Jennings and Christman 2012; Boyarski et al. 2015; 
Emmons and Nowak 2016a; Myrand et al. 2017; Sprague 2017; Nowak et al. 
2019). For northern Mexican gartersnake, telemetry studies indicate 
home ranges of individuals ranging from 1.7 acres (0.7 ha) at a highly 
modified lentic site to 47.0 acres (19.04 ha) along a spatially 
intermittent stream (Boyarski et al. 2015, p. 12; Emmons and Nowak 
2016a, pp. 27-28; Nowak et al. 2019, p. 31). Maximum longitudinal 
length within these home ranges varied from approximately 148 ft (45 m) 
at the lentic site to 2,736 ft (834 m) along the spatially intermittent 
stream (Boyarski et al. 2015, p. 12; Emmons and Nowak 2016a, pp. 27-28; 
Nowak et al. 2019, p. 31). Mean distance to water of northern Mexican 
gartersnake locations ranged from 3.87 to 312.5 ft (1.18 to 95.25 m) 
along Tonto Creek in north-central Arizona (Nowak et al. 2019, p. 40). 
These studies of northern Mexican gartersnake indicate that this 
species overwinters in rodent burrows, cavities below boulders and rock 
fields, and below debris piles located 1.6 ft (0.5 m) to approximately 
558 ft (170 m) from the water's edge (Boyarski et al. 2015, p. 8; 
Emmons and Nowak 2016a, p. 30; Myrand et al. 2017, p. 21). Brumation 
sites were located an average of 129 ft (39.27 m) from the water's edge 
in two different areas along the Verde River in Arizona (Emmons and 
Nowak 2016a, p. 30). Nowak et al. (2019, p. 36) reported brumation 
sites for 14 northern Mexican gartersnakes that ranged from 2 to 1,257 
ft (0.7 to 383 m) from the water's edge along the Tonto River in 
Arizona. Overwintering of seven gartersnakes at brumation sites was 
also recorded within 230 ft (70 m) of ponds, and one gartersnake 
overwintered at a site approximately 1,115 ft (350 m) from a pond 
(Boyarski et al. 2015, pp. 8, 11).
    For narrow-headed gartersnake, telemetry studies in New Mexico on 
the Tularosa River, Gila River, and Whitewater Creek found individuals 
an average of 58.7 ft (17.9 m) from water, with a maximum distance of 
285 ft (87 m) across four different sites on the three streams with a 
sample size of 69 individuals (Jennings and Chirstman 2012, pp. 9-10). 
Researchers found most snakes within 3.28 ft (1 m) of the water's edge 
(Jennings and Christman 2012, pp. 9-10). Narrow-headed gartersnakes 
were found with lowest average distance of 22.7 ft (6.9 m) during the 
dry season of 2010, and highest average distance of 88.3 ft (26.9 m) 
during the wet season in 2010 (Jennings and Chirstman 2012, pp. 9-10). 
Although, Nowak (2006, p. 19) reported that the maximum distance moved 
by one individual was 650 ft (200 m) from water on a steep hillside in 
a narrow canyon, she also reported that during the active season, she 
most often found individuals outside of water under boulders, small 
rocks, and broken concrete slabs located less than 328 ft (100 m) from 
the water's edge within the floodplain of Oak Creek and West Fork Oak 
Creek, Arizona.
    Based on a review of this new information, clarification of Nowak's 
data, and comments we received, it is likely that 600 ft (182.9 m) does 
not accurately capture the lateral extent of terrestrial habitat used 
by either species. Consequently, we have modified the lateral extent 
boundary of critical habitat for both species. For northern Mexican 
gartersnake, we are defining the lateral extent to include the wetland 
or riparian zone adjacent to a stream or lentic water body, whichever 
is greater. Delineating based on riparian zone rather than delineating 
a set distance more accurately captures the foraging habitat used by 
the northern Mexican gartersnake. As described above in this section 
and under ``Hydrologic Processes,'' most northern Mexican gartersnake 
detections ranged from in water in the stream channel up to meadows or 
woodlands within the floodplain at the limit of the riparian zone. We 
are defining the riparian zone as the strip of vegetation along a 
stream that is of distinct composition and density from the surrounding 
uplands, or the area between the stream channel and the upland 
terrestrial ecosystem (Levick et al. 2008, pp. 6, 47). Although 
northern Mexican gartersnakes have been found in a variety of 
vegetation types within this riparian zone (i.e., grasses, shrubs, and 
wetland plants), the underlying characteristic of this habitat needed 
by the gartersnake appears to be dense vegetation or other natural 
structural components that provide cover for the species. Size of the 
riparian zone and composition of plants within the riparian zone varies 
widely across the range of northern Mexican gartersnake. The width of 
critical habitat for northern Mexican gartersnake along streams varies 
from approximately 50 to 7,000 ft (15 to 2,134 m). Because the width of 
wetland and riparian zone varies along and among streams, and some 
streams have little to no riparian habitat but have wetland habitat 
that includes some terrestrial components, delineating these areas 
rather than delineating a set distance from the stream channel better 
captures the needed habitat for the northern Mexican gartersnake.
    For narrow-headed gartersnake, we have modified the lateral extent 
boundary of critical habitat to include aquatic and terrestrial 
features within 89 ft (27 m) of the active channel of a stream. This 
distance captures the greatest average distance moved from the water 
during the wet season on the Tularosa River in New Mexico from a 3-year 
study with a sample size of 69 individuals at two different sites 
(Jennings and Christman 2012, p. 12). This is the largest study to 
date.
    In addition, we have modified the delineation of where terrestrial 
habitat

[[Page 23616]]

begins. We chose to use the active channel instead of bankfull width 
because the active channel effectively defines a river or stream as a 
feature on the landscape (Mersel and Lichvar 2014, pp. 11-12). The 
active channel is established and maintained by flows that occur with 
some regularity (several times per year to several times per decade), 
but not by very rare and extremely high flood events. The outer limits 
of the active channel can generally be defined by three primary 
indicators that together form a discernable mark on the landscape: A 
topographic break in slope, change in vegetation characteristics, and 
change in sediment characteristics (Mersel and Lichvar 2014, pp. 13-
14). The active channel is often a fairly obvious and easy feature to 
identify in the field, allowing for rapid and consistent identification 
(Mersel and Lichvar 2014, p. 14). Further, the active channel can be 
consistently recognized by the public.
    These changes in determining lateral extent from streams have 
reduced the proposed critical habitat designation by 3,458 ac (1,399 
ha), or less than 1 percent, of the area included in the July 10, 2013, 
proposed rule for critical habitat for northern Mexican gartersnake, 
and 41,927 ac (16,967 ha), or 20 percent, of the area included in that 
proposed rule for critical habitat for narrow-headed gartersnake (see 
tables 1a and 1b, below).
    In addition, we are no longer including terrestrial space as a 
separate PBF, but are including both terrestrial and aquatic features 
that make up a stream in a single PBF (PBF 1) that more accurately 
captures the habitat requirements essential to each gartersnake 
species.
Overland Areas for Northern Mexican Gartersnake
    In the July 10, 2013, proposed rule, for northern Mexican 
gartersnake, 5 of the 14 critical habitat units included additional 
terrestrial space beyond the 600-ft (182.9-m) lateral extent from 
bankfull stage of streams (overland areas or terrestrial space). In the 
discussion of space for individual and population growth for normal 
behavior under PBFs, we state that ``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,'' (78 FR 41550, July 10, 2013, p. 78 FR 41554), and 
we cite observations by Drummond and Marcias-Garcia (1983, pp. 24, 35) 
of northern Mexican gartersnakes wandering hundreds of meters away from 
water, as well as Rosen and Schwalbe (1988, p. 27) observing a northern 
Mexican gartersnake 330 ft (100 m) away from permanent water. We 
described these areas as overland areas or terrestrial space between 
springs, seeps, streams, and stock tanks. We did not include these 
areas in a PCE, but we included them in the proposed designation of 
critical habitat. Upland areas that are distant from riparian habitat 
that the snakes use for foraging may be used while moving between 
habitats, but specific habitat attributes in these areas that are 
essential to the snakes have not been identified. In determining which 
areas we will designate as critical habitat from within the 
geographical area occupied by the species at the time of listing, the 
Act directs us to consider the physical or biological features (or PCEs 
under our previous regulations) that are essential to the conservation 
of the species and that may require special management considerations 
or protection. A common characteristic of these overland areas was the 
presence of natural or constructed livestock ponds within a grassland 
landscape in southern Arizona, although we did not define or discuss 
the scope of this grassland landscape in the July 10, 2013, proposed 
rule. We did not know how northern Mexican gartersnakes used the 
grassland landscape in between water features, so we used property and 
watershed boundaries to delineate large landscapes that encompassed the 
features that the species may use. We used a U.S. Geological Survey 
(USGS) Hydrological Unit Code (HUC) level 10 watershed boundary to 
delineate the Upper Santa Cruz River Subbasin Unit. We used property 
ownership boundaries to delineate the following units and subunits: 
Buenos Aires National Wildlife Refuge Unit, Las Cienegas National 
Conservation Area Subunit and Cienega Creek Natural Preserve Subunit in 
the Cienega Creek Subbasin Unit, Appleton-Whittell Research Ranch 
Subunit and Canelo Hills Cienega Preserve Subunit in the Babocomari 
River Subbasin Unit, and San Bernardino National Wildlife Refuge Unit. 
While property boundaries can delineate individual land management 
prescriptions and affect the likelihood for species persistence, 
property boundaries themselves are not linked to the PBFs that are 
essential to the conservation of northern Mexican gartersnake, where 
more accurate mapping methods are available, they should be used as an 
alternative to property boundaries. These overland areas encompassed 
290,620 acres (47,441 ha) in the previous proposed rule, but only 
12,745 acres (5,158 ha) had water bodies within them that contained PCE 
1 and PCE 2, and were considered occupied at the time of listing. In 
other words, 96 percent of these lands included in critical habitat did 
not have PCEs for northern Mexican gartersnake as defined in the July 
10, 2013, proposed rule.
    Upon further inspection of all known locations of the species, no 
northern Mexican gartersnakes have been detected in the aforementioned 
overland areas in southern Arizona outside of stream floodplains. These 
eight lentic sites occupied at the time of listing, including natural 
and constructed ponds, all fall within a stream floodplain, although 
some of these streams are ephemeral. Data are still lacking to explain 
how the species moves through the overland areas between perennial or 
intermittent aquatic features, but we used our re-assessment of 
gartersnake locations in relation to stream floodplains, along with 
additional information obtained since the publication of the July 10, 
2013, proposed rule, to refine the definition of terrestrial space used 
by the species. There is new information about how northern Mexican 
gartersnakes exploit seasonal amphibian prey species in ephemeral 
waters during the rainy season when prey is abundant within these 
grassland landscapes in southern Arizona (d'Orgeix et al. 2013, entire; 
Caldwell 2014, entire). After the first heavy rains of the monsoon 
season in 2012, northern Mexican gartersnakes were found foraging on 
seasonal amphibian prey (spadefood (Spea multiplicata)) and basking at 
the bases of Sacaton grass (Sporobolus wrightii) in and around a ponded 
area within an ephemeral section of the floodplain in O'Donnell Canyon. 
These northern Mexican gartersnakes were 0.75 miles (1.2 km) overland 
and 1.49 miles (2.3 km) along O'Donnell Canyon upstream of the closest 
known population of northern Mexican gartersnakes at Finley Tank 
(d'Orgeix 2013, p. 214). Caldwell (2014, p. 1) also found northern 
Mexican gartersnakes in wetted ephemeral habitat within the Cienega 
Creek floodplain: One in an off-channel marsh, and one in pool of water 
on a road that also contained spadefoot larva and metamorphs. We also 
have updated information on telemetered snakes moving in other 
terrestrial habitats along stream channels in northern Arizona (Emmons 
and Nowak 2013, entire; Emmons and Nowak 2016a, entire; Myrand et al. 
2017, entire), as described earlier. This research has also

[[Page 23617]]

shown that when northern Mexican gartersnakes were surface active in 
habitats with perennial stream flow in northern Arizona, they were 
observed outside of water concealed under dense vegetative most of the 
time. While we do not have similar information for gartersnakes in 
grassland habitats, ephemeral channels in southern Arizona usually have 
more vegetative cover than the surrounding uplands, so we can deduce 
that it is more likely that gartersnakes are using these more densely 
vegetated areas that provide more cover to successfully move between 
aquatic sites in these grasslands. Based on this information, we are 
not including the overland terrestrial space between springs, seeps, 
streams, and stock tanks. In this revised proposed rule, we are 
including the springs, seeps, streams, and stock tanks and the 
ephemeral drainages that connect these wetlands to perennial streams. 
The resulting proposed critical habitat better represents our current 
understanding of the life history of the northern Mexican gartersnake 
and the habitat characteristics that facilitate its life-history 
functions. Consequently, no units or subunits include overland 
grassland areas, and all areas considered occupied under this revised 
proposed rule are adjusted in size to appropriately reflect the PBFs 
(see table 1a, below).
    The removal of overland terrestrial space in these large grasslands 
has reduced the proposed critical habitat designation for northern 
Mexican gartersnake by 285,837 ac (115,674 ha), or 68 percent, of the 
area included in the July 10, 2013, proposed rule.
Elevation
    In the July 10, 2013, proposed rule, we erroneously included some 
areas that are not within the elevation range of narrow-headed 
gartersnake, including portions of the West Fork Gila River, Black 
Canyon, Iron Creek, Diamond Creek, and Whitewater Creek.
    In this revised proposed rule, we add the elevation range of each 
corresponding gartersnake species as a PBF to capture the range of 
where each species has been documented and exclude the areas that are 
outside the elevation ranges where the species occur. This reduces the 
proposed critical habitat designation by 2,320 ac (939 ha), or 1 
percent, of the area included in the July 10, 2013, proposed rule for 
critical habitat for narrow-headed gartersnake (see table 1b, below).

Changes to Criteria Used To Identify Critical Habitat

Occupancy Records

    On July 10, 2013, we published proposed rules to list both 
gartersnake species (78 FR 41500) and to designate critical habitat for 
both gartersnake species (78 FR 41550). On July 8, 2014, we published a 
final rule (79 FR 38678) listing both species.
    In the proposed rule to designate critical habitat (78 FR 41550; 
July 10, 2013), we considered an entire stream as occupied at the time 
of listing for each corresponding gartersnake if it was within the 
historical range of the species, contained aquatic and terrestrial 
components of habitat defined by PCE 1 and PCE 2, had at least one 
record of the species dated 1980 or later, and had at least one native 
prey species present (78 FR 41550, July 10, 2013, p. 78 FR 41556). For 
the northern Mexican gartersnake, we also considered large overland 
areas (grasslands) within specific land ownership or watershed as 
occupied if they met the above criteria. We have reconsidered the use 
the criteria of one record of the species dated 1980 or later as a 
proxy for what was occupied at the time of listing. We received 
comments that using records dated 1980 or later to determine which 
streams are occupied at the time of listing is inconsistent with 
definitions we used to define the status of the northern Mexican 
gartersnake in prior Service status assessment documents, that our 
approach is not supported by the scientific literature, and that low 
gartersnake detection probabilities do not justify a broad historical 
approach to designate critical habitat. Thus, in this revised proposed 
rule, we take a more accurate approach (described below) to conclude 
what areas were likely occupied at the time of listing in 2014.
    For northern Mexican gartersnake, the definition of occupancy we 
used to determine critical habitat in the July 10, 2013, proposed rule 
is significantly different from the criteria that we used to define 
what areas we considered the northern Mexican gartersnake extant or 
extirpated in other previous Service documents. In the 2006 and 2008 
12-month findings (71 FR 56228, September 26, 2006; and 73 FR 71788, 
November 25, 2008, respectively), as well as in updates to the 
``Species Assessment and Listing Priority Form'' described in our 
annual candidate notices of review (see 73 FR 75176, December 10, 2008; 
74 FR 57804, November 9, 2009; 75 FR 69222, November 10, 2010; 76 FR 
66370, October 26, 2011), ``extant'' was defined as areas where the 
species is expected to reliably occur in appropriate habitat as 
supported by museum records or recent, reliable observations. Based on 
this definition, only 42 percent of the total area considered occupied 
at the time of listing by the species in the July 10, 2013, proposed 
critical habitat designation was considered extant from 2006 to 2011. 
From 2006-2011, the Service defined ``extirpated'' as that there have 
been no individuals reported for a decade or longer at a site within 
the historical distribution of the species, despite survey efforts, and 
there is no expectation of natural recovery at the site due to the 
presence of known or strongly suspected causes of extirpation. 
Furthermore, the Service defined ``unknown'' as the species occurred 
based on museum records (mostly historically) but access is restricted, 
or survey data unavailable or insufficient, or where threats could 
preclude occupancy. Of the total area considered occupied by the 
species in the July 10, 2013, proposed critical habitat designation, 16 
percent would have been considered extirpated, 23 percent would have 
been considered unknown, and 19 percent would have had no status based 
on the 2006-2011 definitions of status for northern Mexican 
gartersnake. In the July 10, 2013, proposed listing rule (78 FR 41500), 
we changed how we defined status to correspond with our definition of 
``occupied'' in the July 10, 2013, proposed critical habitat rule (78 
FR 41550). The most significant change in those 2013 publications was 
that we considered a gartersnake species extant in an area if it had 
been reported in an area in the past 33 years regardless of negative 
survey efforts or threats precluding occupancy. We justified using 
records of each species from the 1980s to determine that an area was 
occupied at the time of listing by stating that ``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'' (78 FR 41550, July 10, 2013, p. 78 FR 
41556). For narrow-headed gartersnake, we had no previous Service 
documents that addressed occupancy of the species.
    For this revised proposed rule, we reassessed occupancy at the time 
of listing for each gartersnake by reviewing all records for each 
gartersnake that we used in the July 10, 2013, proposed critical 
habitat rule in conjunction with expected survivorship of each species, 
subsequent surveys in areas that had no

[[Page 23618]]

detection of the corresponding gartersnake species, and changes in 
threats that may have prevented occupancy at time of listing.
    Understanding longevity of a species can inform how long we can 
reasonably expect a species is still extant in an area, regardless of 
detection probability. The oldest estimated northern Mexican 
gartersnake is between 14 and 16 years old, although growth rate 
calculations are still preliminary (M. Ryan 2020). The longest years 
between recaptures from these mark-recapture studies is 9 years (M. 
Ryan 2020, pers. comm.). Narrow-headed gartersnakes may live up to 10 
years or longer in the wild (Rosen and Schwalbe 1988, p. 38). An 
individual narrow-headed gartersnake captured in the wild as an adult 
was kept in captivity for 11 years; and estimated to be 16 years old 
(M. Ryan 2020). Based on this information, we estimate maximum 
longevity for each gartersnake species is 15 years, so that it is 
reasonable to conclude that a gartersnake detected in 1998 or later 
represents a population that could still be present at the time of 
proposed listing in 2013, depending on the extent of threats in the 
area. Although it is possible that gartersnakes are still extant in 
areas where they were detected only during the 1980s, we have 
determined that the best available information reflecting occupancy at 
the time of listing supports a more recent date of records since 1998.
    In the July 10, 2013, proposed critical habitat rule, 8 percent of 
the critical habitat designation for northern Mexican gartersnake and 
17 percent of the designation for narrow-headed gartersnake was 
considered occupied at the time of listing, based solely on records of 
the corresponding species dated before 1998. For northern Mexican 
gartersnake, these areas included Mule Creek Unit, Upper Salt River 
Subbasin Unit, and Agua Fria River Subbasin Unit in their entirety, and 
Bear Canyon Creek Subunit in San Pedro River Subbasin Unit and Turkey 
Creek Subunit in Babocomari River Subbasin Unit. For narrow-headed 
gartersnake, areas included Turkey Creek Subunit in Upper Gila River 
Subbasin Unit; and Salt River, White River, Carrizo Creek, Cibecue 
Creek, and Diamond Creek subunits in Upper Salt River Subbasin Unit. We 
note that the San Bernardino National Wildlife Refuge Unit did not have 
a verified northern Mexican gartersnake record dated 1998 or later. 
This unit was not included in the revised proposed rule. In addition, 
Parker Canyon and Parker Canyon Lake were specifically mentioned as 
part of the occupied Upper Santa Cruz River Unit for northern Mexican 
gartersnake in the July 10, 2013, proposed rule, but the last detection 
of the species in this area was in 1979 (Holycross et al. 2006, 
appendix A). Redrock Canyon does not have a record of the northern 
Mexican gartersnake, and was also erroneously included in the July 10, 
2013, proposed rule. Instead, the species was found in nearby Cott Tank 
Drainage and is included in this revised proposed rule (Jones 2009). 
For narrow-headed gartersnake, we note that the Gila River Subunit in 
the Middle Gila River Subbasin Unit had no records of the species and 
was erroneously included in the July 10, 2013, proposed rule. In 
addition, East Fork Gila River had no confirmed post-1980 records of 
the species and was erroneously included in the July 10, 2013, proposed 
rule (Propst 2015).
    Based on our analyses in the rule listing the two garternakes (79 
FR 38678; July 8, 2014), we conclude that there has been a significant 
decline in both species over the past 50 years. This decline appeared 
to accelerate during the two decades immediately before listing 
occurred. From this observation, we conclude that many areas that were 
occupied by the species in surveys during the 1980s are likely no 
longer occupied because those populations have disappeared. To 
determine where loss of populations was likely, we reviewed survey 
efforts after 1989 that did not detect gartersnakes in some of the 
areas mentioned above, and portions of other units and subunits 
included in the July 10, 2013, proposed critical habitat rule. We 
analyzed this to determine whether the cryptic nature of the species 
was a valid argument for considering areas that only have gartersnake 
records from the 1980s as still occupied at the time of listing in 
2013. All of the surveys conducted since the 1980s included at least 
the same amount or more search effort than those surveys that detected 
each species in the 1980s. Since 1998, researchers have detected each 
gartersnake species in many areas where they were found in the 1980s. 
Areas where each gartersnake was found after 1997 are included in this 
revised proposed rule. This includes portions of 9 of the 13 units for 
northern Mexican gartersnake, and portions of 6 of the 7 units for 
narrow-headed gartersnake from the July 10, 2013, proposed rule. 
Resurveyed areas with no confirmed detection of northern Mexican 
gartersnakes since the 1980s include Mule Creek (Hotle et al. 2012, p. 
1), Black River (Holycross et al. 2006, p. 30), Big Bonito Creek 
(Holycross et al. 2006, p. 64), Verde River downstream of Beasley Flat 
(Holycross et al. 2006, p. 26; Emmons and Nowak 2012, pp. 11-13), Agua 
Fria River (Holycross et al. 2006, pp. 15-18; Burger 2016, p. 3), 
Little Ash Creek (Holycross et al. 2006, p. 19; Emmons and Nowak 2012, 
p. 32; Burger 2016, p. 3), and Black Draw and lentic habitats on San 
Bernardino National Wildlife Refuge (Radke 2006).
    Resurveyed areas with no confirmed detection of narrow-headed 
gartersnakes since the 1980s include the Gila River Subunit downstream 
of the Middle Box (Christman and Jennings 2017, pp. 4-12; Jennings et 
al. 2017, pp. 13-14; Jennings et al. 2018, pp. 10-13; Jennings and 
Christman 2019, p. 5); San Francisco River downstream of confluence 
with Whitewater Creek (Holycross et al. 2006, p. 66; Hellekson 2012), 
and Salt River (Holycross et al. 2006, pp. 38-39). It is reasonable to 
conclude that areas surveyed within 15 years of listing with no 
detection of the corresponding gartersnake species were not occupied at 
the time of listing. Survey efforts in these areas were comparable to 
or greater than surveys conducted in the 1980s that detected the 
species. Additionally, comparable surveys did detect gartersnakes in 
other areas where the species was present in the 1980s. Finally, we 
would expect that some populations would be lost during the decades 
preceding listing when numbers of both gartersnakes were declining. 
These declines are what eventually led to the need to list both 
species.
    As explained extensively in the final listing rule for both 
gartersnake species (79 FR 38678, July 8, 2014, pp. 79 FR 38688-79 FR 
38702), aquatic vertebrate survey efforts throughout the range of both 
species indicate that native prey species of both gartersnakes have 
decreased or are absent, while nonnative predators, including 
bullfrogs, crayfish, and spiny-rayed fish, continue to increase in many 
of the areas where both gartersnakes were present in the 1980s (Emmons 
and Nowak 2012, pp. 11-14; Gibson et al. 2015, pp. 360-364; Burger 
2016, pp. 21-32; Emmons and Nowak 2016a, pp. 43-44; Christman and 
Jennings 2017, p. 14; Hall 2017, pp. 12-13; Jennings et al. 2018, p. 
19). We acknowledge that both gartersnake species are extant in some 
areas that have abundant nonnative, aquatic predators, some of which 
also are prey for gartersnakes, so presence of nonnative aquatic 
predators is not always indicative of absence of these gartersnakes 
(Emmons and Nowak 2012, p. 31; Emmons and Nowak 2016a, p. 13; Emmons et 
al. 2016, entire; Nowak et al. 2016, pp. 5-6; Lashway 2015, p. 5). We

[[Page 23619]]

also acknowledge that we do not have a good understanding of why 
gartersnake populations are able to survive in some areas with aquatic 
predators and not in other areas (Burger 2016, pp. 13-15). However, we 
think it is reasonable to conclude that streams, stream reaches, and 
lentic water bodies were not occupied at the time of listing if they 
have only gartersnake records older than 1998 and have experienced a 
rapid decline in native prey species coupled with an increase in 
nonnative aquatic predators since gartersnakes were detected in these 
areas in the 1980s.
    In summary, through this review of gartersnake occupancy, we 
determined that a stream, stream reach, or lentic water body was 
occupied at the time of listing for each gartersnake species if it is 
within the historical range of the species, contains all PBFs for the 
species, (although the PBFs concerning prey availability and presence 
of nonnative predators are often in degraded condition), and a last 
known record of occupancy in 1998 or later. As a result, six subunits 
in five units of critical habitat for northern Mexican gartersnake and 
nine subunits in four units of critical habitat for narrow-headed 
gartersnake included in the July 10, 2013, proposed rule are no longer 
included in this revised proposed critical habitat designation their 
entirety. This change reduced the proposed critical habitat designation 
by 35,426 ac (14,336 ha), or 9 percent, of the area included in the 
July 10, 2013, proposed rule for northern Mexican gartersnake, and 
47,535 ac (19,237 ha), or 23 percent, of the area included in that 
proposed rule for narrow-headed gartersnake (see tables 1a and 1b, 
below). Other units and subunits are shortened in length due to our 
definition of occupancy as described below under Stream Length.
    We included gartersnake detections of each gartersnake that 
occurred after the species was listed because these areas were likely 
occupied at the time of listing in 2014. Both of these species are 
cryptic in nature and may not be detected without intensive surveys. 
Because populations for these species are generally small, isolated, 
and in decline it is not likely that the species have colonized new 
areas since 2014; these areas were most likely occupied at the time of 
listing, but either had not been surveyed or the species were present 
but not detected during surveys. However, we did not include streams or 
lentic water bodies where gartersnakes were released for recovery 
purposes after the species was listed that had not been historically 
occupied by the species. This added one new unit and five subunits in 
four existing units of critical habitat for northern Mexican 
gartersnake (7,040 ac (2,848 ha)) and five subunits in two units of 
critical habitat for narrow-headed gartersnake (1,181 ac (478 ha)) in 
this revised proposed rule (see tables 1a and 1b, below).

Stream Length

    In the July 10, 2013, proposed critical habitat rule, if a stream 
had at least one known record for the each gartersnake species and at 
least one record of a native prey species currently present, the entire 
stream length was included in proposed critical habitat. In the 
discussion, we stated, ``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'' (78 FR 41550, p. 78 FR 41556). We received numerous 
general comments and comments on specific stream reaches that are not 
habitat for the corresponding gartersnake.
    In this revised proposed rule, for each gartersnake species, we 
used comments we received and reports on water availability, prey 
availability, and gartersnake surveys to re-evaluate all streams and 
determine which stream reaches contain PBFs and where PBFs are lacking. 
Stream reaches that lack PBFs include areas where water flow became 
completely ephemeral along an otherwise perennial or spatially 
intermittent stream, hydrologic processes needed to maintain streams 
could not be recovered, nonnative aquatic predators outnumbered native 
prey species, or streams were outside the elevation range. In addition, 
reaches with multiple negative surveys without a subsequent positive 
survey or reaches that have no records of the corresponding gartersnake 
species are not included, as described above under Occupancy Records. 
We do include stream reaches that lack survey data for the 
corresponding gartersnake, if they have positive observation records of 
the species dated 1998 or later both upstream and downstream of the 
stream reach and have all of the PBFs.
    We also reviewed the best available information we have on home 
range size and potential dispersal distance for each gartersnake 
species to inform upstream and downstream boundaries of each unit and 
subunit of critical habitat. As explained earlier, the maximum 
longitudinal distance measured across home range areas of northern 
Mexican gartersnake tracked for at least one year was 4,852 ft 
(1,478.89 m) for one individual, and ranged from 587.9 to 2,580 ft 
(179.2 to 481.58 m) for eight other northern Mexican gartersnakes 
(Nowak et al. 2019, pp. 24-25). Maximum longitudinal distance measured 
across home range areas of narrow-headed gartersnakes ranged from 82 to 
285 feet (25 to 87 m) (Jennings and Christman 2012, pp. 9-10). These 
longitudinal home range distances were all determined from adult 
gartersnakes, and did not inform how juvenile gartersnakes are 
dispersing along a stream. Juvenile dispersal is important because 
snakes of different age classes behave differently, and juvenile 
gartersnakes may move farther along a stream as they search for and 
establish suitable home ranges than do adults with established home 
ranges. Because we have no information on how juvenile northern Mexican 
gartersnakes and narrow-headed gartersnakes disperse, we used 
information from a long-term dispersal study on neonate, juvenile, and 
adult age classes of the Oregon gartersnake (Thamnophis atratus 
hydrophilus) in a free-flowing stream environment in northern 
California (Welsh et al. 2010, entire). This is the only dispersal 
study available for another aquatic Thamnophis species in the United 
States, so we used it as a surrogate for determining upstream and 
downstream movements of both northern Mexican and narrow-headed 
gartersnakes, which are also aquatic Thamnophis species. The greatest 
movement was made by a juvenile recaptured as an adult 2.2 mi (3.6 km) 
upstream from the initial capture location (Welsh et al. 2010, p. 79). 
Therefore, in this revised proposed rule, we delineate upstream and 
downstream critical habitat boundaries of a stream reach at 2.2 mi (3.6 
km) from a known gartersnake observation record.
    These changes in determining stream length reduced the proposed 
critical habitat designation by 72,955 ac (29,524 ha), or 17 percent, 
of the area included in the July 10, 2013, proposed rule for critical 
habitat for northern Mexican gartersnake, and 101,597 ac (41,115 ha), 
or 48 percent, of the area included in that proposed rule for critical 
habitat for narrow-headed gartersnake (see tables 1a and 1b, below).

[[Page 23620]]



                                    Table 1a--Changes to Northern Mexican Gartersnake Proposed Critical Habitat Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Length miles (kilometers)            Area acres (hectares)
        Previous unit          Previous subunit      New unit        New subunit   ---------------------------------------------------------------------
                                                                                       Previous           New            Previous             New
--------------------------------------------------------------------------------------------------------------------------------------------------------
Upper Gila River.............  ................  Upper Gila River  ...............       148 (239)         13 (21)     21,135 (8,553)        1,132 (458)
                                                  Subbasin.
                               ................  ................  Gila River.....       148 (239)          9 (14)     21,135 (8,553)        1,028 (416)
                               ................  ................  Duck Creek.....               0           4 (6)                  0           104 (42)
Mule Creek...................  ................  Removed *.......  ...............         19 (30)               0      2,579 (1,044)                  0
Upper Salt River.............  ................  Removed *.......  ...............       156 (251)               0     22,218 (8,991)                  0
                               Black River.....  ................  Removed *......       114 (184)               0     16,392 (6,634)                  0
                               Big Bonito Creek  ................  Removed *......         42 (67)               0      5,826 (2,358)                  0
Tonto Creek..................  ................  Tonto Creek.....  ...............        65 (105)         32 (52)      8,936 (3,616)      4,302 (1,741)
Verde River..................  ................  Verde River       ...............       201 (323)         61 (99)    29,191 (11,813)      5,246 (2,123)
                                                  Subbasin.
                               Upper Verde       ................  Verde River....       140 (225)         35 (56)     20,526 (8,307)      4,133 (1,672)
                                River.
                               Oak Creek.......  ................  Oak Creek......         39 (62)         23 (37)      5,533 (2,239)        1,014 (410)
                               Spring Creek....  ................  Spring Creek...         23 (36)           4 (6)      3,131 (1,267)            99 (40)
Agua Fria River..............  ................  Removed *.......  ...............         56 (91)               0      7,946 (3,215)                  0
                               Agua Fria River   ................  Removed *......         49 (80)               0      6,989 (2,828)                  0
                                Mainstem.
                               Little Ash Creek  ................  Removed *......         10 (11)               0          957 (387)                  0
Bill Williams River..........  ................  Bill Williams     ...............         36 (58)         29 (46)      5,412 (2,190)      4,049 (1,639)
                                                  River Subbasin.
                               ................  ................  Bill Williams           36 (58)         15 (24)      5,412 (2,190)        1,805 (730)
                                                                    River.
                               ................  ................  Big Sandy River               0          8 (13)                  0          932 (377)
                               ................  ................  Santa Maria                   0           5 (9)                  0        1,312 (531)
                                                                    River.
                               ................  Lower Colorado    ...............               0             n/a                  0      4,467 (1,808)
                                                  River.
Buenos Aires NWR.............  ................  Arivaca Cienega.  ...............             n/a           3 (5)   117,313 (47,475)           211 (86)
Cienega Creek Subbasin.......  ................  Cienega Creek     ...............             n/a         46 (73)    50,393 (20,393)        2,030 (821)
                                                  Subbasin.
                               Cienega Creek...  ................  Cienega Creek 1        7+ (11+)         30 (48)        1,113 (450)        1,613 (653)
                               Cienega Creek     ................  Removed *......             n/a             n/a      4,260 (1,724)                  0
                                Natural
                                Preserve.
                               Las Cienegas NCA  ................  Removed *......             n/a             n/a    45,020 (18,219)                  0
                                2.
                               ................  ................  Empire Gulch                n/a          7 (11)                n/a          326 (132)
                                                                    and Empire
                                                                    Wildlife Pond.
                               ................  ................  Gardner Canyon              n/a          7 (11)                n/a            74 (30)
                                                                    and Maternity
                                                                    Wildlife Pond.
                               ................  ................  Unnamed                     n/a           2 (3)                n/a             15 (6)
                                                                    Drainage and
                                                                    Gaucho Tank.
Redrock Canyon...............  ................  Removed * 3.....  ...............         14 (23)               0        1,972 (798)                  0
Upper Santa Cruz River         ................  Upper Santa Cruz  ...............             n/a         23 (36)   113,895 (46,092)          496 (201)
 Subbasin 4.                                      River Subbasin.
                               ................  ................  Sonoita Creek..               0           3 (5)                  0           224 (91)
                               ................  ................  Cott Tank                   n/a           2 (3)                  0             13 (5)
                                                                    Drainage.
                               ................  ................  Santa Cruz              14 (22)          7 (11)                n/a           161 (65)
                                                                    River.

[[Page 23621]]

 
                               ................  ................  Unnamed                     n/a           5 (7)                n/a            42 (17)
                                                                    Drainage and
                                                                    Pasture 9 Tank.
                               ................  ................  Unnamed                     n/a           2 (3)                n/a            25 (10)
                                                                    Drainage and
                                                                    Sheehy Spring.
                               ................  ................  Scotia Canyon..             n/a           4 (7)                n/a            31 (13)
                               ................  ................  FS799 Tank.....             n/a             n/a                n/a          0.7 (0.3)
                               ................  ................  Unnamed                     n/a             n/a                n/a         0.1 (<0.1)
                                                                    Wildlife Pond.
                               ................  ................  Removed *                 6 (9)               0                n/a                  0
                                                                    (Parker
                                                                    Canyon).
San Pedro River Subbasin.....  ................  Upper San Pedro   ...............       165 (266)         35 (57)     23,690 (9,587)      5,850 (2,367)
                                                  River Subbasin.
                               San Pedro River.  ................  San Pedro River       158 (255)         22 (35)     22,669 (9,174)      5,126 (2,074)
                               Bear Canyon       ................  Removed *......          7 (11)               0        1,022 (414)                  0
                                Creek.
                               ................  ................  House Pond.....               0             n/a                  0          0.6 (0.2)
Babocomari River Subbasin....  ................  Incorporated 5..  ...............         45 (72)             n/a     14,334 (5,801)                n/a
                               Babocomari River  ................  Babocomari              24 (24)          6 (10)      3,454 (1,398)          404 (164)
                                                                    River.
                               Turkey Creek....  ................  Removed *......         12 (19)               0        1,678 (679)                  0
                               Appleton-         ................  Removed * 6....             n/a             n/a      7,798 (3,156)                  0
                                Whittell
                                Research Ranch.
                               Canelo Hills      ................  Removed * 6....             n/a             n/a           213 (86)                  0
                                Cienega
                                Preserve.
                               Post Canyon.....  ................  Post Canyon....         6+ (9+)           3 (5)          795 (322)            77 (31)
                               O'Donnell Canyon  ................  O'Donnell               3+ (5+)           4 (7)          398 (161)           239 (97)
                                                                    Canyon.
                               ................  ................  Unnamed                     n/a       0.5 (0.7)                n/a              3 (1)
                                                                    Drainage and
                                                                    Finley Tank.
San Bernardino NWR...........  ................  Removed *.......  ...............             n/a             n/a        2,387 (966)                  0
                                                                                   ---------------------------------------------------------------------
    Totals...................  ................  ................  ...............     932 (1,500)       241 (388)  421,423 (170,544)    27,784 (11,244)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Numbers may not sum due to rounding.
* ``Removed '' means this unit or subunit, which was proposed as critical habitat for the northern Mexican gartersnake in the July 10, 2013, proposed
  rule (78 FR 41550), is not included in this revised proposed critical habitat designation.
1 Portions of Cienega Creek in the Cienega Creek Natural Preserve and Las Cienegas National Conservation Area are now included in Cienega Creek subunit.
2 All new named subunits in the Cienega Creek Subbasin unit were included in the July 10, 2013, proposed rule's Las Cienegas National Conservation Area
  (NCA) subunit.
3 The gartersnake record was in Cott Tank Drainage not Redrock Canyon so is now captured in the Cott Tank Drainage subunit.
4 All new named subunits except for Sonoita Creek were included in the July 10, 2013, proposed rule's Upper Santa Cruz River Subbasin unit.
5 The named subunits of the Babocomari River Subbasin unit in the July 10, 2013, proposed rule (78 FR 41550) are now incorporated into the Upper San
  Pedro River Subbasin unit.
6 Portions of these two subunits are now included in Post Canyon, O'Donnell Canyon, and Unnamed Drainage and Finley Tank subunits.


[[Page 23622]]


                                     Table 1b--Changes to Narrow-Headed Gartersnake Proposed Critical Habitat Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                       Length miles (kilometers)            Area acres (hectares)
        Previous unit          Previous subunit      New unit        New subunit   ---------------------------------------------------------------------
                                                                                       Previous           New            Previous             New
--------------------------------------------------------------------------------------------------------------------------------------------------------
Upper Gila River Subbasin....  ................  Upper Gila River  ...............       325 (526)       104 (167)    49,903 (20,195)      5,429 (2,197)
                                                  Subbasin.
                               Gila River......  ................  Gila River.....       148 (239)         46 (74)     21,135 (8,553)      3,510 (1,420)
                               Turkey Creek....  ................  Removed *......  ..............               0        2,338 (946)                  0
                               West Fork Gila    ................  West Fork Gila          37 (60)         12 (19)      5,169 (2,092)          562 (228)
                                River.                              River.
                               Little Creek....  ................  Little Creek...  ..............          7 (11)        2,236 (905)           162 (65)
                               Middle Fork Gila  ................  Middle Fork             37 (60)         14 (23)      4,964 (2,009)          569 (230)
                                River.                              Gila River.
                               Iron Creek......  ................  Iron Creek.....         12 (20)           2 (3)        1,731 (701)            58 (23)
                               Gillita Creek...  ................  Gillita Creek..         12 (20)          6 (10)        1,704 (690)           149 (60)
                               East Fork Gila    ................  Removed *......         28 (44)               0      3,579 (1,148)                  0
                                River.
                               Black Canyon....  ................  Black Canyon...         26 (42)         10 (16)      3,503 (1,418)          251 (102)
                               Diamond Creek...  ................  Diamond Creek..         25 (41)          6 (10)      3,545 (1,435)           169 (68)
Middle Gila River Subbasin...  ................  Removed *.......  ...............        63 (101)               0      8,814 (3,567)                  0
                               Gila River......  ................  Removed *......           3 (5)               0          432 (175)                  0
                               Eagle Creek.....  Eagle Creek 1...  ...............         60 (97)          7 (11)      8,382 (3,392)          336 (136)
San Francisco River Subbasin.  ................  San Francisco     ...............       301 (476)       129 (207)    45,075 (18,241)      4,905 (1,985)
                                                  River Subbasin.
                               San Francisco     ................  San Francisco         163 (263)        71 (115)     23,178 (9,380)      3,120 (1,263)
                                River.                              River.
                               Whitewater Creek  ................  Whitewater       ..............          9 (14)      2,289 (1,145)           208 (84)
                                                                    Creek.
                               Saliz Creek.....  ................  Saliz Creek....          8 (13)          8 (13)        1,099 (445)           218 (88)
                               Tularosa River..  ................  Tularosa River.         35 (56)         20 (32)      4,728 (1,913)          829 (336)
                               n/a.............  ................  Negrito Creek..               0         13 (21)                  0          337 (136)
                               South Fork        ................  South Fork              11 (17)          8 (13)        1,483 (600)           192 (78)
                                Negrito Creek.                      Negrito Creek.
                               ................  Blue River        ...............             n/a        64 (103)                n/a      2,971 (1,202)
                                                  Subbasin.
                               Blue River......  ................  Blue River.....         53 (86)         52 (84)      7,432 (3,007)      2,504 (1,013)
                               Campbell Blue     ................  Campbell Blue           22 (26)          7 (11)      3,008 (1,217)          361 (146)
                                Creek.                              Creek.
                               Dry Blue Creek..  ................  Dry Blue Creek.          9 (15)           4 (6)        1,320 (534)           106 (43)
Upper Salt River Subbasin....  ................  Black River       ...............       352 (654)         51 (82)    58,014 (23,478)        1,607 (650)
                                                  Subbasin.
                               Salt River......  ................  Removed *......        86 (139)               0     12,877 (5,211)                  0
                               White River.....  ................  Removed *......         18 (29)               0      2,588 (1,047)                  0
                               Carrizo Creek...  ................  Removed *......        64 (104)               0      9,033 (1,229)                  0
                               Cibecue Creek...  ................  Removed *......         48 (77)  ..............      6,669 (2,699)  .................
                               Diamond Creek...  ................  Removed *......         22 (36)               0      3,117 (1,261)                  0
                               Black River.....  ................  Black River....       114 (184)         23 (37)     16,384 (6,630)          763 (309)
                               n/a.............  ................  Bear Wallow                   0          6 (10)                  0           174 (71)
                                                                    Creek.
                               n/a.............  ................  North Fork Bear               0           2 (3)                  0            61 (25)
                                                                    Wallow Creek.
                               n/a.............  ................  Reservation                   0           5 (8)                  0           132 (54)
                                                                    Creek.
                               n/a.............  ................  Fish Creek.....               0           4 (6)                  0           107 (43)
                               n/a.............  ................  East Fork Black               0         12 (19)                  0          370 (150)
                                                                    River.
                               Canyon Creek....  Canyon Creek 1..  ...............         53 (85)          8 (13)      7,346 (2,973)           232 (94)
Tonto Creek..................  ................  Tonto Creek.....  ...............        91 (146)         41 (66)     12,795 (5,178)        1,390 (562)
                               Tonto Creek.....  ................  Tonto Creek....         54 (87)         28 (45)      7,712 (3,121)        1,078 (436)
                               Houston Creek...  ................  Houston Creek..         15 (24)           1 (2)        2,046 (828)             18 (7)
                               Haigler Creek...  ................  Haigler Creek..         22 (35)         12 (19)      3,037 (1,229)          294 (119)

[[Page 23623]]

 
Verde River..................  ................  Verde River       ...............       248 (400)         58 (93)    35,586 (14,401)        1,832 (741)
                                                  Subbasin.
                               Verde River.....  ................  Verde River....       128 (205)         27 (43)     18,721 (7,576)          923 (374)
                               Oak Creek.......  ................  Oak Creek......         51 (83)         24 (39)      7,369 (2,982)          748 (303)
                               West Fork Oak     ................  West Fork Oak           16 (26)          7 (11)        2,137 (865)           161 (65)
                                Creek.                              Creek.
                               East Fork Verde   ................  Removed *......         53 (86)               0      7,360 (2,978)                  0
                                River.
                                                                                   ---------------------------------------------------------------------
    Totals...................  ................  ................  ...............   1,380 (2,221)       461 (742)   210,189 (85,060)     18,701 (7,568)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Numbers may not sum due to rounding.
* ``Removed'' means this unit or subunit, which was proposed as critical habitat for the narrow-headed gartersnake in the July 10, 2013, proposed rule
  (78 FR 41550), is not included in this revised proposed critical habitat designation.
1 Eagle Creek and Canyon Creek were proposed as a critical habitat subunits for the narrow-headed gartersnake in the July 10, 2013, proposed rule (78 FR
  41550), but are their own units in this revised proposed critical habitat designation.

Physical or Biological Features

    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12(b), in determining which areas we will designate as 
critical habitat from within the geographical area occupied by the 
species at the time of listing, we consider the physical or biological 
features that are essential to the conservation of the species and that 
may require special management considerations or protection. The 
regulations at 50 CFR 424.02 define ``physical or biological features 
essential to the conservation of the species'' as the features that 
occur in specific areas and that are essential to support the life-
history needs of the species, including, but not limited to, water 
characteristics, soil type, geological features, sites, prey, 
vegetation, symbiotic species, or other features. A feature may be a 
single habitat characteristic, or a more complex combination of habitat 
characteristics. Features may include habitat characteristics that 
support ephemeral or dynamic habitat conditions. Features may also be 
expressed in terms relating to principles of conservation biology, such 
as patch size, distribution distances, and connectivity. For example, 
physical features essential to the conservation of the species might 
include gravel of a particular size required for spawning, alkali soil 
for seed germination, protective cover for migration, or susceptibility 
to flooding or fire that maintains necessary early-successional habitat 
characteristics. Biological features might include prey species, forage 
grasses, specific kinds or ages of trees for roosting or nesting, 
symbiotic fungi, or a particular level of nonnative species consistent 
with conservation needs of the listed species. The features may also be 
combinations of habitat characteristics and may encompass the 
relationship between characteristics or the necessary amount of a 
characteristic essential to support the life history of the species. In 
considering whether features are essential to the conservation of the 
species, the Service may consider an appropriate quality, quantity, and 
spatial and temporal arrangement of habitat characteristics in the 
context of the life-history needs, condition, and status of the 
species. These characteristics include, but are not limited to, space 
for individual and population growth and for normal behavior; food, 
water, air, light, minerals, or other nutritional or physiological 
requirements; cover or shelter; sites for breeding, reproduction, or 
rearing (or development) of offspring; and habitats that are protected 
from disturbance.

Summary of Essential Physical or Biological Features

    We derive the specific PBFs essential to the conservation of 
northern Mexican and narrow-headed gartersnakes from studies of this 
species' habitat, ecology, and life history as described above. 
Additional information can be found in the final listing rule published 
in the Federal Register on July 8, 2014 (79 FR 38678); the previous 
proposed critical habitat rule (78 FR 41550; July 10, 2013), as well as 
comments we received on previous proposed critical habitat rule; and 
information in this rule under Changes from Previously Proposed 
Critical Habitat, above. We have determined that the following PBFs are 
essential to the conservation of northern Mexican and narrow-headed 
gartersnakes.
Northern Mexican Gartersnake
    1. Perennial or spatially intermittent streams that provide both 
aquatic and terrestrial habitat that allows for immigration, 
emigration, and maintenance of population connectivity of northern 
Mexican gartersnakes and contain:
    (A) Slow-moving water (walking speed) with in-stream pools, off-
channel pools, and backwater habitat;
    (B) Organic and natural inorganic structural features (e.g., 
boulders, dense aquatic and wetland vegetation, leaf litter, logs, and 
debris jams) within the stream channel for thermoregulation, shelter, 
foraging opportunities, and protection from predators;
    (C) Terrestrial habitat adjacent to the stream channel that 
includes riparian vegetation, small mammal burrows, boulder fields, 
rock crevices, and downed woody debris for thermoregulation, shelter, 
foraging opportunities, brumation, and protection from predators; and
    (D) Water quality that is absent of pollutants or, if pollutants 
are present, at levels low enough such that recruitment of northern 
Mexican gartersnakes is not inhibited.
    2. Hydrologic processes that maintain aquatic and terrestrial 
habitat through:
    (A) A natural flow regime that allows for periodic flooding, or if 
flows are modified or regulated, a flow regime that allows for the 
movement of water, sediment, nutrients, and debris through the stream 
network; and
    (B) Physical hydrologic and geomorphic connection between a stream 
channel and its adjacent riparian areas.
    3. Prey base of primarily native anurans, fishes, small mammals, 
lizards, and invertebrate species.

[[Page 23624]]

    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 is not inhibited and 
maintenance of viable prey populations is still occurring.
    5. Elevations from 130 to 8,500 ft (40 to 2,590 m).
    6. Lentic wetlands including off-channel springs, cienegas, and 
natural and constructed ponds (small earthen impoundment) with:
    (A) Organic and natural inorganic structural features (e.g., 
boulders, dense aquatic and wetland vegetation, leaf litter, logs, and 
debris jams) within the ordinary high water mark for thermoregulation, 
shelter, foraging opportunities, brumation, and protection from 
predators;
    (B) Riparian habitat adjacent to ordinary high water mark that 
includes riparian vegetation, small mammal burrows, boulder fields, 
rock crevices, and downed woody debris for thermoregulation, shelter, 
foraging opportunities, and protection from predators; and
    (C) Water quality that is absent of pollutants or, if pollutants 
are present, at levels low enough such that recruitment of northern 
Mexican gartersnakes is not inhibited.
    7. Ephemeral channels that connect perennial or spatially 
intermittent perennial streams to lentic wetlands in southern Arizona 
where water resources are limited.
Narrow-Headed Gartersnake
    1. Perennial streams or spatially intermittent streams that provide 
both aquatic and terrestrial habitat that allows for immigration, 
emigration, and maintenance of population connectivity of narrow-headed 
gartersnakes and contain:
    (A) Pools, riffles, and cobble and boulder substrate, with low 
amount of fine sediment and substrate embeddedness;
    (B) Organic and natural inorganic structural features (e.g., cobble 
bars, rock piles, large boulders, logs or stumps, aquatic and wetland 
vegetation, logs, and debris jams) in the stream channel for basking, 
thermoregulation, shelter, prey base maintenance, and protection from 
predators;
    (C) Water quality that is absent of pollutants or, if pollutants 
are present, at levels low enough such that recruitment of narrow-
headed gartersnakes is not inhibited; and
    (D) Terrestrial habitat within 89 ft (27 m) of the active stream 
channel that includes boulder fields, rocks, and rock structures 
containing cracks and crevices, small mammal burrows, downed woody 
debris, and vegetation for thermoregulation, shelter sites, and 
protection from predators.
    2. Hydrologic processes that maintain aquatic and riparian habitat 
through:
    (A) A natural flow regime that allows for periodic flooding, or if 
flows are modified or regulated, a flow regime that allows for the 
movement of water, sediment, nutrients, and debris through the stream 
network, as well as maintenance of native fish populations; and
    (B) Physical hydrologic and geomorphic connection between the 
active stream channel and its adjacent terrestrial areas.
    3. Prey base of native fishes, or soft-rayed, nonnative fish 
species.
    4. An absence of nonnative predators, such as fish species of the 
families Centrarchidae and Ictaluridae, bullfrogs, and crayfish, or 
occurrence of nonnative predators at low enough densities such that 
recruitment of narrow-headed gartersnakes is not inhibited and 
maintenance of viable prey populations is still occurring.
    5. Elevations of 2,300 to 8,200 ft (700 to 2,500 m).

Special Management Considerations or Protection

    When designating critical habitat, we assess whether the specific 
areas within the geographical 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. In this revised proposed critical habitat rule, we are not 
changing any of the special management considerations for either 
gartersnake species' proposed critical habitat.

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. In accordance 
with the Act and our implementing regulations at 50 CFR 424.12(b), we 
review available information pertaining to the habitat requirements of 
the species and identify specific areas within the geographical area 
occupied by the species at the time of listing and any specific areas 
outside the geographical area occupied by the species that are 
essential for the species' conservation to be considered for 
designation as critical habitat. We are proposing to designate critical 
habitat for both gartersnake species in areas considered currently 
occupied. We are not currently proposing to designate any areas outside 
the geographical area occupied by the species because we have not 
identified any unoccupied areas that meet the definition of critical 
habitat. We are not aware of any other areas within the historical 
range of the species that maintain perennial water, have suitable prey, 
and support an aquatic community that is not dominated by nonnative 
predators. Therefore, although there may be a future need to expand the 
area occupied by one or both gartersnake species to reach recovery, 
there are no unoccupied areas that are currently essential to the 
species conservation and that should be designated as critical habitat.
    To identify areas proposed for critical habitat for the northern 
Mexican and narrow-headed gartersnakes, we used a variety of sources 
for species data including riparian species survey reports, museum 
records, heritage data from State wildlife agencies, peer-reviewed 
literature, agency reports, and interviews with species experts. 
Holycross et al. (in press, entire) was a key source of information for 
vouchered historical and current records of both gartersnake species 
across their respective ranges. Other sources for current records of 
the northern Mexican gartersnake included Cotten et al. (2014, entire), 
Holycross et al. (2006, entire), and Rosen et al. (2001, entire). 
Christman and Jennings (2017, entire), Hellekson (2012), Jennings et 
al. (2017, entire), Jennings and Christman (2019, entire), and Jennings 
et al. (2018) were important sources 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 and heritage data from State wildlife agencies for fish 
and amphibians as they captured important data on the existing 
community ecology that affects the status of these gartersnakes within 
their ranges. In addition to species data sources, we used publicly 
available geospatial datasets depicting water bodies, stream flow, 
vegetation type, and elevation to identify areas proposed for critical 
habitat.
    The maps define the critical habitat designation, as modified by 
any accompanying regulatory text, presented at the end of this document 
under Proposed Regulation Promulgation. We include more detailed 
information on the proposed boundaries of the critical habitat 
designation in the preamble of this document. We will make the

[[Page 23625]]

coordinates or plot points or both on which each map is based available 
to the public on http://www.regulations.gov at Docket No. FWS-R2-ES-
2020-0011, 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).

Areas Occupied at the Time of Listing

    We are proposing for designation of critical habitat lands that we 
have determined were occupied at the time of listing and contain one or 
more of the physical or biological features to support life-history 
processes essential to the conservation of the species. As explained 
under Occupancy Records, above, this proposed critical habitat 
designation does not include all streams known to have been occupied by 
the species historically or the entire stream known to have been 
occupied by the species historically. Instead, it focuses on occupied 
streams or stream reaches within the historical range with positive 
survey records from 1998 to 2019 that have retained the necessary PBFs 
that will allow for the maintenance and expansion of existing 
populations. In summary, for areas within the geographic area occupied 
by the species at the time of listing, we delineated critical habitat 
unit boundaries using the following criteria:

Northern Mexican Gartersnake

    1. We mapped records of observations of northern Mexican 
gartersnake from 1998 to 2019. We then examined these areas to 
determine if northern Mexican gartersnake could still occur in them, as 
described below.
    2. We identified streams in which northern Mexican gartersnakes 
were found since 1980 (used flowline layer in the USGS National 
Hydrography Dataset to represent stream centerlines).
    3. We identified and removed upstream and downstream ends of 
streams that were below 130 ft or above 8,500 ft elevation using USGS 
National Elevation Dataset.
    4. We identified perennial, intermittent, and ephemeral reaches of 
streams. We removed end reaches of streams that are ephemeral based on 
FCode attribute of the flowline layer in the USGS National Hydrography 
Dataset or information from peer review and public comments. We 
identified native prey species along each stream using geospatial 
datasets, literature, peer review, and public comments.
    5. We identified prey species along each stream using geospatial 
datasets, literature, peer review, and public comments. We removed 
stream reaches that were documented to not contain prey species.
    6. We identified and removed stream reaches with an abundance of 
nonnative predators including fish, crayfish, or bullfrogs. (We used a 
combination of factors to determine nonnative presence and impact to 
the species. This evaluation included records from 1980 by looking at 
subsequent negative survey data for northern Mexican gartersnakes along 
with how the nonnative predator community had changed since those 
gartersnakes were found, in addition to the habitat condition and 
complexity. Most of the areas surveyed in the 1980s that had been re-
surveyed with negative results for gartersnakes had significant changes 
to the nonnative predator community, which also decreased prey 
availability for the gartersnakes. These areas were removed from 
revised proposed critical habitat.)
    7. We identified and removed stream reaches where stocking or 
management of predatory sportfish is a priority and is conducted on a 
regular basis.
    8. We identified and included those stream reaches on private land 
without public access that lack survey data but that have positive 
survey records from 1998 forward both upstream and downstream of the 
private land and have stream reaches with PBFs 1 and 2.
    9. We used a surrogate species to determine potential neonate 
dispersal along a stream, which is 2.2 miles (3.5 km). We then 
identified the most upstream and downstream records of northern Mexican 
gartersnake along each continuous stream reach determined by criteria 1 
through 8, above, and extended the stream reach to include this 
dispersal distance.
    10. After identifying the stream reaches that met the above 
parameters, we then connected those reaches between that have the PBFs. 
We consider these areas between survey records occupied because the 
species occurs upstream and downstream and multiple PBFs are present 
that allow the species to move through these stream reaches.
    11. We identified the springs, cienegas, and natural or constructed 
ponds (livestock tanks) in which records of observations of the species 
from 1998 to 2019 were found and included them in this revised proposed 
critical habitat.
    12. We identified ephemeral reaches of occupied perennial or 
intermittent streams that serve as corridors between springs, cienegas, 
and natural or constructed ponds (livestock tanks).
    13. We identified and included the wetland and riparian area 
adjacent to streams, springs, cienegas, and ponds to capture the 
wetland and riparian habitat needed by the species for 
thermoregulation, foraging, and protection from predators. We used the 
wetland and riparian layers of the Service's National Wetlands 
Inventory dataset and aerial photography in Google Earth Pro to 
identify these areas.

Narrow-headed Gartersnake

    1. We mapped records of narrow-headed gartersnake from 1998 to 
2019. We then examined these areas to determine if narrow-headed 
gartersnake could still occur here, as described below.
    2. We identified the streams in which narrow-headed gartersnakes 
were found since 1998 (used flowline layer in the USGS National 
Hydrography Dataset to represent stream centerlines).
    3. We identified and removed upstream and downstream ends of 
streams that were below 2,300 ft or above 8,200 ft in elevation using 
USGS National Elevation Dataset.
    4. We identified perennial, intermittent, and ephemeral reaches of 
streams. We removed end reaches of streams that are ephemeral or 
intermittent based on FCode attribute of the flowline layer in the USGS 
National Hydrography Dataset or information from peer review and public 
comments.
    5. We identified native and nonnative prey species along each 
stream using geospatial datasets, literature, peer review, and public 
comments. We removed stream reaches that did not have prey species.
    6. We identified and removed stream reaches with an abundance of 
nonnative predators including fish, crayfish, and bullfrogs. (We 
examined a combination of factors to determine nonnative presence and 
impact to the species. This included evaluating gartersnake records 
from 1998 by looking at subsequent negative survey data for narrow-
headed gartersnakes along with how the nonnative predator community had 
changed since those gartersnakes were found, in addition to the habitat 
condition and complexity. Most of the areas surveyed in the 1980s that 
had been re-surveyed with negative results for gartersnakes had 
significant changes to the nonnative predator community, which also 
decreased prey availability for the gartersnakes. These areas were 
removed from revised proposed critical habitat.)
    7. We identified and removed stream reaches where stocking or 
management of predatory sportfish is a priority and is conducted on a 
regular basis.
    8. We identified and included those stream reaches on private land 
without

[[Page 23626]]

public access that lack survey data but that have positive narrow-
headed gartersnake survey records from 1998 forward both upstream and 
downstream of the private land and have stream reaches with PBFs 1 and 
2.
    9. We used a surrogate species to determine potential neonate 
dispersal along a stream, which is 2.2 mi (3.5 km). We then identified 
the most upstream and downstream records of narrow-headed gartersnake 
along each continuous stream reach determined by criteria 1 through 8, 
above, and extended the reach to include this dispersal distance.
    10. After identifying the stream reaches that met the above 
parameters, we then connected those reaches between that had the PBFs. 
We consider these areas between survey records occupied because the 
species occurs upstream and downstream and multiple PBFs are present 
that allow the species to move through these stream reaches.
    11. We identified the average distance narrow-headed gartersnakes 
moved laterally from the water's edge in streams, which is 89 ft (27 
m), to capture the wetland and terrestrial habitat needed by the 
species for thermoregulation and protection from predators. We used the 
wetland layer of the Service's National Wetlands Inventory dataset and 
aerial photography in Google Earth Pro to identify the water's edge in 
streams.
    When determining proposed critical habitat boundaries, we made 
every effort to avoid including developed areas such as lands covered 
by buildings, pavement, and other structures because such lands lack 
physical or biological features necessary for northern Mexican and 
narrow-headed gartersnakes. However, constructed fish barriers in 
streams within the proposed designated critical habitat are part of the 
designation and are needed to manage the exclusion of nonnative 
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 the 
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 were occupied at the time of listing and contain one or 
more of the physical or biological features that are essential to 
support life-history processes of the species.

Proposed Critical Habitat Designation

Northern Mexican Gartersnake

    We are proposing 241 stream mi (388 km) within the identified 
wetland and riparian habitat needed for basking, cover, and foraging, 
totaling 27,784 ac (11,244 ha) in nine units as the revised proposed 
critical habitat for northern Mexican gartersnake. Land ownership 
within proposed critical habitat for the northern Mexican gartersnake 
in acres is broken down as follows: Federal (62 percent), State 
(Arizona and New Mexico) (5 percent), Tribal (0.3 percent), and private 
(32 percent) (see table 2a, below). The critical habitat areas we 
describe below constitute our current best assessment of areas that 
meet the definition of critical habitat for northern Mexican 
gartersnake. We consider all units occupied at the time of listing, and 
all units contain essential PBFs that may require special management 
considerations or protection.

                            Table 2a--Land Ownership and Size of Northern Mexican Gartersnake Proposed Critical Habitat Units
             [Area estimates reflect all land within critical habitat unit boundaries. County-owned lands are considered as private lands.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Land ownership by type acres (hectares)               Total size
                   Unit                                Subunit           ----------------------------------------------------------------      acres
                                                                              Federal          State          Tribal          Private       (hectares)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Upper Gila River Subbasin..............  Gila River..................  ..............          22 (9)  ..............     1,006 (407)     1,028 (416)
                                            Duck Creek..................  ..............  ..............  ..............        104 (42)        104 (42)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................  ..............          22 (9)  ..............     1,110 (449)     1,132 (458)
2. Tonto Creek............................  ............................   3,337 (1,350)  ..............  ..............       966 (391)   4,302 (1,741)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................   3,337 (1,350)  ..............  ..............       966 (391)   4,302 (1,741)
3. Verde River Subbasin...................  Verde River.................       646 (261)       570 (231)         88 (36)   2,829 (1,145)   4,133 (1,672)
                                            Oak Creek...................        193 (78)        134 (54)  ..............       687 (278)     1,014 (410)
                                            Spring Creek................          17 (7)          1 (<1)  ..............         80 (32)         99 (40)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................       856 (346)       705 (285)         88 (36)   3,597 (1,456)   5,246 (2,123)
4. Bill Williams River Subbasin...........  Bill Williams River.........     1,002 (405)        202 (82)  ..............       601 (243)     1,805 (730)
                                            Big Sandy River.............       339 (137)  ..............  ..............       593 (240)       932 (377)
                                            Santa Maria River...........       780 (316)  ..............  ..............       532 (215)     1,312 (531)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................     2,121 (858)        202 (82)  ..............     1,727 (699)   4,049 (1,639)
5. Lower Colorado River...................  ............................   4,467 (1,808)  ..............  ..............  ..............   4,467 (1,808)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................   4,467 (1,808)  ..............  ..............  ..............   4,467 (1,808)
6. Arivaca Cienega........................  ............................        149 (60)          1 (<1)  ..............         62 (25)        211 (86)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................        149 (60)          1 (<1)  ..............         62 (25)        211 (86)
7. Cienega Creek Subbasin.................  Cienega Creek...............       755 (306)       308 (125)  ..............       550 (222)     1,613 (653)
                                            Empire Gulch and Empire            268 (109)         57 (23)  ..............  ..............       326 (132)
                                             Wildlife Pond.

[[Page 23627]]

 
                                            Gardner Canyon and Maternity         74 (30)  ..............  ..............  ..............         74 (30)
                                             Wildlife Pond.
                                            Unnamed Drainage and Gaucho           15 (6)  ..............  ..............  ..............          15 (6)
                                             Tank.
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................     1,112 (451)       366 (148)  ..............       550 (222)     2,030 (821)
8. Upper Santa Cruz River Subbasin........  Sonoita Creek...............  ..............  ..............  ..............        224 (91)        224 (91)
                                            Cott Tank Drainage..........          13 (5)  ..............  ..............  ..............          13 (5)
                                            Santa Cruz River............  ..............         70 (28)  ..............         91 (37)        161 (65)
                                            Unnamed Drainage and Pasture  ..............         36 (15)  ..............           5 (2)         42 (17)
                                             9 Tank.
                                            Unnamed Drainage and Sheehy   ..............           5 (2)  ..............          20 (8)         25 (10)
                                             Spring.
                                            Scotia Canyon...............         31 (13)  ..............  ..............  ..............         31 (13)
                                            FS799 Tank..................       0.7 (0.3)  ..............  ..............  ..............       0.7 (0.3)
                                            Unnamed Wildlife Pond.......  ..............  ..............  ..............      0.1 (<0.1)      0.1 (<0.1)
    Unit Total............................  ............................         45 (18)        111 (45)  ..............       340 (138)       496 (201)
9. Upper San Pedro River Subbasin.........  San Pedro River.............   4,911 (1,988)  ..............  ..............        215 (87)   5,126 (2,074)
                                            Babocomari River............        197 (80)           8 (3)  ..............        199 (81)       404 (164)
                                            O'Donnell Canyon............         58 (24)  ..............  ..............        181 (73)        239 (97)
                                            Post Canyon.................         30 (12)  ..............  ..............         47 (19)         77 (31)
                                            Unnamed Drainage and Finley   ..............  ..............  ..............           3 (1)           3 (1)
                                             Tank.
                                            House Pond..................       0.6 (0.2)  ..............  ..............  ..............       0.6 (0.2)
                                                                         -------------------------------------------------------------------------------
Unit Total................................  ............................   5,197 (2,103)           8 (3)  ..............       645 (261)   5,850 (2,367)
    Grand Total...........................  ............................  17,284 (6,995)     1,414 (572)         88 (36)   8,996 (3,640)          27,784
                                                                                                                                                (11,244)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding.

    We present brief descriptions of all units, and reasons why they 
meet the definition of critical habitat for northern Mexican 
gartersnake, below.
Upper Gila River Subbasin Unit
    The Upper Gila River Subbasin Unit is located in southwestern New 
Mexico southeast of the towns of Cliff and Gila, in Grant County. This 
unit consists of 1,132 ac (458 ha) along 13 stream mi (21 km) in two 
subunits with 9 stream mi (14 km) along the Gila River and 4 stream mi 
(6 km) along Duck Creek. The New Mexico Department of Game and Fish, 
New Mexico State land department, and private entities manage lands 
within this unit. Several reaches of the Gila River have been adversely 
affected by channelization and diversions, which have reduced or 
eliminated base flow. As a whole, this unit contains PBFs 1, 2, and 5, 
but PBFs 3 and 4 are in degraded condition. PBFs 6 and 7 do not apply 
to this unit. The physical or biological features in this unit may 
require special management consideration due to competition with, and 
predation by, 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.
    Lands owned by Freeport McMoRan in the Upper Gila River Subbasin 
Unit on the Gila River and Duck Creek are being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act. A total of 515 ac (208 ha), or 45 percent, of this 
unit are being considered for exclusion (see Application of Section 
4(b)(2) of the Act, below).
Tonto Creek Unit
    The Tonto Creek Unit is generally located near the towns of Gisela 
and Punkin Center, Arizona, in Gila County. This unit consists of 4,302 
ac (1,741 ha) of critical habitat along 32 stream mi (52 km) of Tonto 
Creek. The downstream end of critical habitat is the spillway elevation 
of Theodore Roosevelt Lake (2,120 ft (646 m)) near the confluence with 
Bumblebee Creek. The Tonto National Forest is the primary land manager 
in this unit, with additional lands privately owned. Some reaches along 
Tonto Creek experience seasonal drying because of regional groundwater 
pumping, while others are affected by diversions. 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. Theodore Roosevelt Lake is a nonnative sport fishery and 
supports predators of the northern Mexican gartersnake, so that the 
northern Mexican gartersnake may be subject to higher mortality from 
predation by nonnative fish at the downstream end of this unit, 
especially when the lake level is at spillway elevation. In general, 
this unit contains PBFs 1, 2, 3, and 5, but PBF 4 is in degraded 
condition. PBFs 6 and 7 do not apply to this unit. The physical or 
biological features in this unit may require special management 
consideration due to competition with, and predation by, nonnative 
species that are present in this unit; water diversions causing loss of 
base flow; flood-control

[[Page 23628]]

projects; and development of areas adjacent to or within proposed 
critical habitat.
Verde River Subbasin Unit
    The Verde River Subbasin Unit is generally located near the towns 
of Cottonwood, Cornville, and Camp Verde, Arizona, in Yavapai County. 
This unit consists of 5,246 ac (2,123 ha) along 61 stream mi (98 km) in 
three subunits: 35 stream mi (56 km) of the Verde River, including 
Tavasci Marsh and Peck Lake; 23 stream mi (37 km) of Oak Creek; and 4 
stream mi (6 km) of Spring Creek. The Verde River Subbasin Unit occurs 
on lands managed by the U.S. Forest Service on Coconino and Prescott 
National Forests; National Park Service (NPS) at Tuzigoot National 
Monument; Arizona Game and Fish Department at Bubbling Ponds and Page 
Springs fish hatcheries; Arizona State Parks at Deadhorse Ranch and 
Verde River Greenway State Natural Area; Arizona State Trust; Yavapai-
Apache Nation; and private entities. Crayfish, bullfrogs, and 
nonnative, spiny-rayed fish are present in some of this unit. Proposed 
groundwater pumping of the Big Chino Aquifer may adversely affect 
future base flow in the Verde River. Development along the Verde River 
has eliminated habitat along portions of the Verde River through the 
Verde Valley. As a whole, this unit contains PBFs 1, 2, 3, and 5, but 
PBF 4 is in degraded condition. The physical or biological features in 
this unit may require special management consideration due to 
competition with, and predation by, 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.
    Lands in the Verde River Subunit include The Nature Conservancy's 
Verde Springs Preserve, Verde Valley property, Yavapai-Apache Nation, 
and Salt River Project's Camp Verde Riparian Preserve. Lands owned by 
the Yavapai-Apache Nation, and lands within Salt River Project's Camp 
Verde Riparian Preserve are being considered for exclusion from the 
final rule for critical habitat under section 4(b)(2) of the Act. Lands 
in Oak Creek Subunit include Arizona Game and Fish Department's (AGFD) 
Bubbling Ponds and Page Springs fish hatcheries, which are also being 
considered for exclusion from the final rule for critical habitat. A 
total of 460 ac (186 ha), or 9 percent, of this unit are being 
considered for exclusion (see Application of Section 4(b)(2) of the 
Act, below).
Bill Williams River Subbasin Unit
    The Bill Williams River Subbbasin Unit is generally located in 
western Arizona, northeast of Parker, Arizona, in La Paz and Mohave 
Counties. This unit consists of 4,049 ac (1,639 ha) along 29 stream mi 
(46 km) in three subunits: 15 stream mi (24 km) of Bill Williams River; 
8 stream mi (13 km) of Big Sandy River; and 5 stream mi (9 km) of Santa 
Maria River. The Bill Williams River Subbasin Unit occurs on lands 
managed by the Bureau of Land Management (BLM) within the Rawhide 
Mountains Wilderness, Swansea Wilderness, and Three Rivers Riparian 
Area of Critical Environmental Concern (ACEC); Arizona State Parks at 
Alamo Lake State Park; Arizona State Land Department; and private 
landowners. This unit contains lowland leopard frogs and native fish 
appear to be largely absent, although longfin dace have been detected 
in the Santa Maria River Subunit. As a whole, this unit contains PBFs 
1, 2, 3, and 5, but PBF 4 is in degraded condition. PBFs 6 and 7 do not 
apply to this unit. Crayfish and several species of nonnative, spiny-
rayed fish maintain populations in reaches of the three rivers included 
in the Bill Williams River Subbasin Unit. The physical or biological 
features in this unit may require special management consideration due 
to competition with, and predation by, nonnative species that are 
present in this unit and flood-control projects.
    Lands within the AGFD's Planet Ranch Conservation and Wildlife Area 
property in the Bill Williams River Subunit are being considered for 
exclusion from the final rule for critical habitat under section 
4(b)(2) of the Act. A total of 329 ac (133 ha), or 8 percent, of this 
unit are being considered for exclusion (see Application of Section 
4(b)(2) of the Act, below).
Lower Colorado River Unit
    The Colorado River Unit is generally located in western Arizona in 
Mojave County. This unit consist of 4,467 ac (1,808 ha) within the 
floodplain of the Colorado River but does not include the main 
channelized portion of the river. This unit falls completely within the 
Service's Havasu National Wildlife Refuge. Several species of 
nonnative, spiny-rayed fish maintain robust populations in this unit. 
In general, this unit contains PBFs 1, 2, and 5, but PBFs 3 and 4 are 
in degraded condition. PBFs 6 and 7 do not apply to this unit. The 
physical or biological features in this unit may require special 
management consideration due to competition with, and predation by, 
nonnative species that are present in this unit and flood-control 
projects. No areas within this unit are considered for exclusion.
Arivaca Cienega Unit
    The Arivaca Cienega Unit is generally located in southern Arizona, 
in and around the town of Arivaca in Pima County, Arizona. This unit 
consists of 211 ac (86 ha), along 3 stream mi (5 km) of Arivaca Creek 
within Arivaca Cienega. This unit occurs on lands managed by the 
Service at Buenos Aires National Wildlife Refuge, Arizona State Land 
Department, and private landowners. Drought, bullfrogs, and crayfish 
are a concern in the Arivaca Cienega Unit. In general, this unit 
contains PBFs 2 and 5, but PBFs 1, 3, and 4 are in degraded condition. 
PBFs 6 and 7 do not apply to this unit. The physical or biological 
features in this unit may require special management consideration due 
to loss of perennial flow, as well as competition with, and predation 
by, nonnative species that are present in this unit. No areas within 
this unit are considered for exclusion.
Cienega Creek Subbasin Unit
    The Cienega Creek Subbasin Unit is generally located in southern 
Arizona southeast of the city of Tucson and town of Vail, north of the 
town of Sonoita, west of the Rincon Mountains, and east of the Santa 
Rita Mountains in Pima County. This unit consists of 2,030 ac (821 ha) 
along 46 stream mi (73 km) in four subunits: 30 stream mi (48 km) of 
Cienega Creek; 7 stream mi (11 km) of Empire Gulch, including Empire 
Wildlife Pond; 2 stream mi (3 km) of an unnamed drainage to Gaucho 
Pond, including Gaucho Pond; and 7 stream mi (11 km) of Gardner Canyon, 
including Maternity Wildlife Pond. The unnamed drainage to Gaucho Pond 
is an ephemeral channel that may serve as a movement corridor for 
northern Mexican gartersnakes. The Cienega Creek Subbasin Unit occurs 
on lands managed by BLM on Las Cienegas National Conservation Area 
(NCA), Arizona State Land Department, Pima County on Cienega Creek 
Preserve, and private landowners. Recent, ongoing bullfrog eradication 
on and around Las Cienegas NCA has reduced the threat of bullfrogs in 
much of this unit. As a whole, this unit contains PBFs 1, 2, 3, 5, 6, 
and 7, but PBF 4 is in degraded condition. 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, continuing bullfrog management, and eliminating 
or

[[Page 23629]]

reducing other predatory nonnative species.
    Lands within Pima County's Cienega Creek Natural Preserve in the 
Cienega Creek Subunit are being considered for exclusion from the final 
rule for critical habitat under section 4(b)(2) of the Act. A total of 
543 ac (220 ha), or 27 percent, of this unit are being considered for 
exclusion (see Application of Section 4(b)(2) of the Act, below). 
However, Pima County has requested that these lands not be excluded 
from the final rule.
Upper Santa Cruz River Subbasin Unit
    The Santa Cruz River Subbasin Unit is generally located in southern 
Arizona, south of the town of Sonoita and within the town of Patagonia, 
southeast of the Santa Rita Mountains, and west of the Patagonia 
Mountains in Santa Cruz and Cochise Counties. This unit consists of 496 
ac (201 ha) along 23 stream mi (36 km) in eight subunits: FS 799 Tank; 
an unnamed wildlife pond; 3 stream mi (5 km) of Sonoita Creek; 4 stream 
mi (7 km) of Scotia Canyon; 2 stream mi (3 km) of Cott Tank Drainage; 7 
stream mi (11 km) of Santa Cruz River; 5 stream mi (7 km) of an unnamed 
drainage to Pasture 9 Tank, including Pasture 9 Tank; and 2 stream mi 
(3 km) of an unnamed drainage to Sheehy Spring, including Sheehy 
Spring. The latter two unnamed drainages are ephemeral channels that 
may serve as movement corridors for northern Mexican gartersnakes. The 
Upper Santa Cruz River Subbasin Unit occurs on lands managed by 
Coronado National Forest, Arizona State Parks at San Rafael State 
Natural Area, Arizona State Land Department, and private landowners 
(including The Nature Conservancy at Patagonia-Sonoita Creek Preserve 
and San Rafael Cattle Company at San Rafael Ranch). Native fish, 
bullfrogs, Sonoran tiger salamanders, and Chiricahua leopard frogs 
provide prey for northern Mexican gartersnakes in the Santa Cruz River 
Subbasin Unit. Bullfrogs and nonnative spiny-ray fish remain an issue 
in this unit. As a whole, this unit contains PBFs 1, 2, 3, 5, 6, and 7, 
but PBF 4 is in degraded condition. 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 predatory nonnative species.
    Lands within the San Rafael Cattle Company's San Rafael Ranch in 
the Santa Cruz River Subunit, Unnamed Drainage and Pasture 9 Tank 
Subunit, and Unnamed Drainage and Sheehy Spring Subunit are being 
considered for exclusion from the final rule for critical habitat under 
section 4(b)(2) of the Act. Lands within The Nature Conservancy's 
Patagonia-Sonoita Creek Preserve in the Sonoita Creek Subunit, as well 
as the Unnamed Wildlife Pond Subunit, which are both on private lands, 
are also being considered for exclusion. A total of 238 ac (96 ha), or 
48 percent, of this unit are being considered for exclusion (see 
Application of Section 4(b)(2) of the Act, below).
Upper San Pedro River Subbasin Unit
    The Upper San Pedro River Subbasin Unit is generally located in 
southeastern Arizona, east and west of Sierra Vista and south of the 
town of Elgin, in Cochise and Santa Cruz Counties. This unit consists 
of 5,850 ac (2,367 ha) in six subunits along 35 stream mi (57 km): 22 
stream mi (35 km) of the San Pedro River; 6 stream mi (10 km) of the 
Babocomari River; 4 stream mi (7 km) in O'Donnell Canyon; 3 stream mi 
(5 km) in Post Canyon; 0.5 stream mi (0.7 km) in an ephemeral drainage 
to Finley Tank, including Finley Tank; and House Pond. The Upper San 
Pedro River Subbasin Unit occurs primarily on lands managed by BLM on 
the San Pedro River Riparian and Las Cienegas NCAs, and also includes 
lands managed by the U.S. Forest Service on Coronado National Forest, 
Arizona State Land Department, and private entities. The unit includes 
portions of the Canelo Hills Preserve owned by The Nature Conservancy 
and portions of the Appleton-Whittell Research Ranch managed by several 
private and Federal landowners. Native fish and leopard frogs occur in 
House Pond and O'Donnell Canyon subunits and provide a prey base for 
northern Mexican gartersnakes. Crayfish, bullfrogs, and nonnative, 
spiny-rayed fish occur in the San Pedro River and Babocomari subunits 
and are an ongoing threat to northern Mexican gartersnakes. As a whole, 
this unit contains PBFs 1, 2, 5, 6, and 7, but PBFs 3 and 4 are in 
degraded condition. The physical or biological features in Upper San 
Pedro River Subbasin Unit may require special management consideration 
due to competition with, and predation by, predatory nonnative species 
that are present in this unit.
    Lands owned by The Nature Conservancy at Canelo Hills Preserve and 
lands owned by the National Audubon Society at Appleton-Whittell 
Research Ranch in the O'Donnell Canyon Subunit are being considered for 
exclusion from the final rule for critical habitat. In addition, Fort 
Huachuca has requested the Service to consider for exclusion based on 
national security lands managed by BLM, Arizona State Land Department, 
and private entities within the San Pedro River and Babocomari River 
subunits. A total of 5,320 ac (2,152 ha), or 91 percent, of this unit 
are being considered for exclusion (see Application of Section 4(b)(2) 
of the Act, below).

Narrow-Headed Gartersnake

    We are proposing 461 stream mi (742 km) within a 89-ft (27-m) 
lateral extent of the active stream channel, totaling 18,701 ac (7,568 
ha) comprising 8 units as critical habitat for the narrow-headed 
gartersnake in Greenlee, Graham, Apache, Yavapai, Gila, and Coconino 
Counties in Arizona, as well as in Grant, Hidalgo, and Catron Counties 
in New Mexico. Land ownership within proposed critical habitat for the 
narrow-headed gartersnake is broken down as follows: Federal (66 
percent), State (Arizona and New Mexico) (2 percent), Tribal (3 
percent), and private (29 percent) (see table 2b, below). The critical 
habitat areas we describe below constitute our current best assessment 
of areas that meet the definition of critical habitat for narrow-headed 
gartersnake. We consider all units occupied at the time of listing, and 
all units contain essential PBFs that may require special management 
considerations or protection.

                             Table 2b--Land Ownership and Size of Narrow-Headed Gartersnake Proposed Critical Habitat Units
             [Area estimates reflect all land within critical habitat unit boundaries. County-owned lands are considered as private lands.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      Land ownership by type acres (hectares)
                   Unit                                Subunit           ----------------------------------------------------------------  Size of unit
                                                                              Federal          State          Tribal          Private
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Upper Gila River Subbasin..............  Gila River..................     1,123 (455)        119 (48)  ..............     2,267 (917)   3,510 (1,420)

[[Page 23630]]

 
                                            West Fork Gila River........       358 (145)        154 (62)  ..............         51 (20)       562 (228)
                                            Little Creek................        157 (64)           5 (2)  ..............  ..............        162 (65)
                                            Middle Fork Gila River......       569 (230)  ..............  ..............  ..............       569 (230)
                                            Iron Creek..................         58 (23)  ..............  ..............  ..............         58 (23)
                                            Gilita Creek................        149 (60)  ..............  ..............  ..............        149 (60)
                                            Black Canyon................        245 (99)  ..............  ..............           6 (2)       251 (102)
                                            Diamond Creek...............        169 (68)  ..............  ..............  ..............        169 (68)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................   2,827 (1,144)       278 (113)  ..............     2,323 (940)   5,429 (2,197)
2. San Francisco River Subbasin...........  San Francisco River.........     1,679 (680)  ..............  ..............     1,441 (583)   3,121 (1,263)
                                            Whitewater Creek............        112 (45)  ..............  ..............         96 (39)        208 (84)
                                            Saliz Creek.................        182 (74)  ..............  ..............         36 (15)        218 (88)
                                            Tularosa River..............       338 (137)  ..............  ..............       492 (199)       829 (336)
                                            Negrito Creek...............       272 (110)  ..............  ..............         65 (26)       337 (136)
                                            South Fork Negrito Creek....        171 (69)  ..............  ..............          21 (9)        192 (78)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................   2,753 (1,114)  ..............  ..............     2,152 (871)   4,905 (1,985)
3. Blue River Subbasin....................  Blue River..................     2,105 (852)  ..............  ..............       399 (162)   2,504 (1,013)
                                            Campbell Blue Creek.........       300 (121)  ..............  ..............         61 (25)       361 (146)
                                            Dry Blue Creek..............        106 (43)  ..............  ..............  ..............        106 (43)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................   2,510 (1,016)  ..............  ..............       460 (186)   2,971 (1,202)
4. Eagle Creek............................  ............................         99 (40)  ..............        236 (96)          1 (<1)       336 (136)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................         99 (40)  ..............        236 (96)          1 (<1)       336 (136)
5. Black River Subbasin...................  Black River.................       653 (264)  ..............        111 (45)  ..............       763 (309)
                                            Bear Wallow Creek...........        127 (51)  ..............         47 (19)  ..............        174 (71)
                                            North Fork Bear Wallow Creek         61 (25)  ..............  ..............  ..............         61 (25)
                                            Reservation Creek...........         96 (39)  ..............         36 (14)  ..............        132 (54)
                                            Fish Creek..................        107 (43)  ..............  ..............  ..............        107 (43)
                                            East Fork Black River.......       370 (150)  ..............  ..............  ..............       370 (150)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................     1,414 (572)  ..............        194 (78)  ..............     1,607 (650)
6. Canyon Creek...........................  ............................        155 (63)  ..............         77 (31)  ..............        232 (94)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................        155 (63)  ..............         77 (31)  ..............        232 (94)
7. Tonto Creek Subbasin...................  Tonto Creek.................     1,003 (406)  ..............  ..............         75 (30)     1,078 (436)
                                            Houston Creek...............          16 (6)  ..............  ..............           2 (1)          18 (7)
                                            Haigler Creek...............       266 (108)  ..............  ..............         28 (11)       294 (119)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................     1,285 (520)  ..............  ..............        105 (43)     1,390 (562)
8. Verde River Subbasin...................  Verde River.................       823 (333)  ..............  ..............        101 (41)       923 (374)
                                            Oak Creek...................       360 (146)         51 (21)  ..............       337 (136)       748 (303)
                                            West Fork Oak Creek.........        161 (65)  ..............  ..............  ..............        161 (65)
                                                                         -------------------------------------------------------------------------------
    Unit Total............................  ............................     1,343 (544)         51 (21)  ..............       437 (177)     1,832 (741)
                                                                         -------------------------------------------------------------------------------
        Total.............................  ............................  12,386 (5,013)       329 (133)       507 (205)   5,479 (2,217)  18,701 (7,568)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Area sizes may not sum due to rounding.

    We present brief descriptions of all units, and reasons why they 
meet the definition of critical habitat for narrow-headed gartersnake, 
below.
Gila River Subbasin Unit
    The Gila River Subbasin Unit is generally located in southwestern 
New Mexico, east of Glenwood, and west and north of Silver City in 
Grant and Hidalgo Counties, New Mexico. This unit consists of 5,429 ac 
(2,197 ha) in 8 subunits along 104 stream mi (167 km): 46 stream mi (74 
km) of the Gila River, 12 stream mi (19 km) of West Fork Gila River, 14 
stream mi (23 km) of Middle Fork Gila River, 10 stream mi (16 km) of 
Black Canyon, 6 stream mi (10 km) of Diamond Creek, 6 stream mi (10 km) 
of Gilita Creek, 2 stream mi (3 km) of Iron Creek, and 7 stream mi (11 
km) of Little Creek. The Gila River Subbasin Unit consists of lands 
primarily managed by the U.S. Forest Service on the Gila National 
Forest; BLM within the Lower Box and Middle Gila Box ACECs and Gila 
Lower Box Wilderness Study Area; NPS on Gila Cliff Dwellings National 
Monument; New Mexico Department of Game and Fish on Heart Bar Wildlife 
Area, Redrock State Wildlife Experimental Area, and Gila Bird Area; 
State Trust lands; and private ownership, including lands owned by 
Freeport McMoRan Corporation.

[[Page 23631]]

    Some reaches of the Gila River have been adversely affected by 
channelization and water diversions. In November 2014, the New Mexico 
Interstate Stream Commission provided notice to the Secretary of the 
Interior that the State of New Mexico intends to construct the New 
Mexico Unit of the Central Arizona Project as authorized by the 
Colorado River Basin Project Act of 1968 (Central Arizona Project 2015, 
p. 5-6). The New Mexico Unit of the Central Arizona Project will divert 
up to 14,000 ac-ft per year from the upper Gila River and its 
tributaries for consumptive use in New Mexico. However, the Secretary 
of the Interior denied an extension to divert additional funding, and 
no record of decision for a project design was issued by a December 31, 
2019, deadline. Therefore, the future of the project is unknown. 
Historically, the West and Middle Forks Gila River maintained large 
populations of bullfrogs and nonnative, spiny-rayed fish. Wildfires 
have burned at both moderate and high severity within the unit and 
likely resulted in significant flooding with excessive ash and sediment 
loads. These sediment and ash-laden floods can reduce populations of 
both nonnative predatory species and native prey species for narrow-
headed gartersnakes in affected streams for many years. The Gila River, 
West Fork Gila River, Little Creek, Iron Creek, Black Canyon, and 
Diamond Creek subunits have PBFs 1, 2, 3, and 5, but PBF 4 is in 
degraded condition. The Middle Fork Gila River Subunit has PBF 1, 2, 4, 
and 5 but PBF 3 is in degraded condition. The physical or biological 
features in this unit may require special management consideration due 
to competition with, and predation by, 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.
    Lands owned by Freeport McMoRan Corporation along the Gila River in 
the Gila River Subunit are being considered for exclusion from the 
final rule for critical habitat under section 4(b)(2) of the Act. A 
total of 563 ac (228 ha), or 10 percent, of this unit are being 
considered for exclusion (see Application of Section 4(b)(2) of the 
Act, below).
San Francisco River Subbasin Unit
    The San Francisco River Subbasin Unit is generally located in 
southwestern New Mexico near the towns of Glenwood and Reserve, and 
east of Luna, in Catron County. This unit consists of 4,905 ac (1,985 
ha) in 6 subunits along 129 stream mi (207 km): 71 stream mi (115 km) 
of San Francisco River, 9 stream mi (14 km) of Whitewater Creek, 8 
stream mi (13 km) of Saliz Creek, 20 stream mi (32 km) of Tularosa 
River, 13 stream mi (21 km) of Negrito Creek, and 8 stream mi (13 km) 
of South Fork Negrito Creek. The San Francisco River Subbasin Unit 
consists of lands managed primarily by the U.S. Forest Service on Gila 
National Forest and private landowners.
    Water diversions have dewatered sections of the San Francisco River 
Subunit in the upper Alma Valley and at Pleasanton, New Mexico. The San 
Francisco River Subunit also has historically maintained populations of 
bullfrogs, crayfish, and nonnative, spiny-rayed fish at various 
densities along its course. Wildfires have burned at both moderate and 
high severity within the unit and likely resulted in significant 
flooding with excessive ash and sediment loads. These sediment and ash-
laden floods can reduce populations of both nonnative predatory species 
and native prey species for narrow-headed gartersnakes in affected 
streams for many years. San Francisco River Subunit has PBFs 1, 2, and 
5, but PBFs 3 and 4 are in degraded condition. Whitewater Creek Subunit 
has PBFs 1, 2, 4, and 5, but PBF 3 is in degraded condition. Tularosa 
River, Saliz Creek, Negrito Creek, and subunits have PBFs 1, 2, 3, and 
5, but PBF 4 is in degraded condition. South Fork Negrito Creek Subunit 
has adequate PBFs. The physical or biological features in this unit may 
require special management consideration due to competition with, and 
predation by, nonnative species that are present in this unit; water 
diversions that reduce base flow; potential for high-intensity 
wildfires; and human recreation and development of areas adjacent to 
proposed critical habitat. No areas within this unit are considered for 
exclusion.
Blue River Subbasin Unit
    The Blue River Subbasin Unit is generally located near the east 
central border of Arizona northeast of Clifton in Greenlee County, and 
just into west-central New Mexico in Catron County. This unit consists 
of a total of 2,971 ac (1,202 ha) along 64 stream mi (103 km): 52 
stream mi (84 km) of Blue River, 7 stream mi (11 km) of Campbell Blue 
Creek, and 4 stream mi (6 km) of Dry Blue Creek. Blue River Subbasin 
Unit consists of lands managed primarily by the U.S. Forest Service on 
Gila and Apache-Sitgreaves National Forests, and private landowners. 
The fish community of the Blue River is highly diverse and largely 
native, but nonnative fish are present. Native fish restoration is 
actively occurring in the Blue River, including construction of a fish 
barrier, mechanical removal of nonnative fish, and repatriation and 
monitoring of federally listed warm-water fishes (Robinson and Crowder 
2015, p. 24; Robinson and Love-Chezem 2015, entire). Wildfires have 
burned at both moderate and high severity within the unit and likely 
resulted in significant flooding with excessive ash and sediment loads. 
These sediment and ash-laden floods can reduce populations of both 
nonnative predatory species and native prey species for narrow-headed 
gartersnakes in affected streams for many years. The Blue River and Dry 
Blue Creek subunits have PBFs 1, 2, 3, and 5, but PFB 4 is in degraded 
condition. Campbell Blue Creek Subunit has PBFS 1, 2, 4, and 5, but PBF 
3 may be in degraded condition. The physical or biological features in 
this unit may require special management consideration to maintain or 
develop physical or biological features, including preventing 
reinvasion of nonnative species, and continuing to reestablish native 
prey species. No areas within this unit are considered for exclusion.
Eagle Creek Unit
    The Eagle Creek Unit is generally located in eastern Arizona near 
Morenci and includes portions of Graham and Greenlee Counties. This 
unit consists of a total of 336 ac (136 ha) along 7 stream mi (11 km) 
of Eagle Creek. The majority of lands within this unit are managed by 
the San Carlos Apache Tribe and the U.S. Forest Service on the Gila 
National Forest. This unit has PBFs 1, 2, 3, and 5, but PBF 4 is 
deficient. Special management in this unit 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 maintenance of adequate base flow in Eagle Creek.
    Lands owned by the San Carlos Apache Tribe in the Eagle Creek Unit 
are being considered for exclusion from the final rule for critical 
habitat under section 4(b)(2) of the Act. A total of 236 ac (96 ha), or 
70 percent, of this unit are being considered for exclusion (see 
Application of Section 4(b)(2) of the Act, below).
Black River Subbasin Unit
    The Black River Subbasin Unit is generally located along the 
Mogollon Rim in east-central Arizona, east of Maverick and west of 
Hannigan Meadow, and includes portions of Apache, Graham, and Greenlee

[[Page 23632]]

Counties. This unit consists of a total of 1,607 ac (650 ha) in 6 
subunits along 51 stream mi (82 km): 23 stream mi (37 km) of Black 
River, 6 stream mi (10 km) of Bear Wallow Creek, 2 stream mi (3 km) of 
North Fork Bear Wallow Creek, 5 stream mi (8 km) of Reservation Creek, 
4 stream mi (6 km) of Fish Creek, and 12 stream mi (19 km) of East Fork 
Black River. The majority of lands within this unit are managed by the 
U.S. Forest Service on Apache-Sitgreaves National Forest, with 
additional lands managed by the White Mountain Apache and San Carlos 
Apache Tribes.
    Water in the Black River Subbasin is diverted for use at the 
Morenci Mine, which may affect base flow. Wildfires have burned at both 
moderate and high severity within the unit and likely resulted in 
significant flooding with excessive ash and sediment loads. These 
sediment and ash-laden floods can reduce populations of both nonnative 
predatory species and native prey species for narrow-headed 
gartersnakes in affected streams for many years. In general, this unit 
has PBFs 1, 2, 3, and 5, but PBF 4 is in degraded condition. The 
physical or biological features in this unit may require special 
management consideration due to competition with, and predation by, 
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.
    Lands owned by the White Mountain Apache and San Carlos Apache 
Tribes along the Black River, Bear Wallow Creek, and Reservation Creek 
of the Black River Subbasin Unit are being considered for exclusion 
from the final rule for critical habitat under section 4(b)(2) of the 
Act. A total of 195 ac (79 ha), or 12 percent, of this unit are being 
considered for exclusion (see Application of Section 4(b)(2) of the 
Act, below).
Canyon Creek Unit
    The Canyon Creek Unit is generally located along the Mogollon Rim 
in east-central Arizona, and falls within Gila County. This unit 
consists of 232 ac (94 ha) along 8 stream mi (13 km) of Canyon Creek. 
The Tonto National Forest manages the majority of lands within this 
unit; however, the White Mountain Apache Tribe also has land within 
this unit. This unit contains sufficient physical or biological 
features, but these features may require special management 
consideration including preventing invasion by nonnative predatory 
species as well as the potential for high-intensity wildfires.
    Lands owned by the White Mountain Apache Tribe in the Canyon Creek 
Unit are being considered for exclusion from the final rule for 
critical habitat under section 4(b)(2) of the Act. A total of 77 ac (31 
ha), or 33 percent, of this unit are being considered for exclusion 
(see Application of Section 4(b)(2) of the Act, below).
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 1,390 ac (562 ha) in 3 
subunits along 41 stream mi (66 km): 28 stream mi (45 km) of Tonto 
Creek, 1 stream mi (2 km) of Houston Creek, and 12 stream mi (19 km) of 
Haigler Creek. Land ownership or land management within this unit 
consists of lands managed by the U.S. Forest Service on Tonto National 
Forest in the Hellsgate Wilderness and privately owned lands.
    Some reaches along Tonto Creek experience seasonal drying as a 
result of regional groundwater pumping, while others are or may be 
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 unit has 
PBFs 1, 2, 3, and 5, but PBF 4 is in degraded condition. The physical 
or biological features in this unit may require special management 
consideration due to competition with, and predation by, 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. No areas within 
this unit are considered for exclusion.
Verde River Subbasin Unit
    The Verde River Subbasin Unit is generally located near 
Perkinsville and Sedona, Arizona, west of Paulden, Arizona, in Coconino 
and Yavapai Counties. This unit consists of 1,832 ac (741 ha) in 3 
subunits along 58 stream mi (93 km): 27 stream mi (43 km) of Verde 
River, 24 stream mi (39 km) of Oak Creek, and 7 stream mi (11 km) of 
West Fork Oak Creek. Verde River Subbasin Unit occurs on lands managed 
by the U.S. Forest Service on Prescott and Coconino National Forests, 
Arizona State Parks at Redrock State Park, and private entities. 
Proposed groundwater pumping of the Big Chino Aquifer may adversely 
affect future base flow in the Verde River. In general, the physical or 
biological features in this unit are sufficient, but may require 
special management consideration due to competition with, and predation 
by, nonnative species that are present; water diversions; groundwater 
pumping potentially resulting in drying of habitat; potential for high-
intensity wildfires; and human development of areas adjacent to 
proposed critical habitat. No areas within this unit are considered for 
exclusion.

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.
    We published a final rule with a revised definition of destruction 
or adverse modification on August 27, 2019 (84 FR 44976). Destruction 
or adverse modification means a direct or indirect alteration that 
appreciably diminishes the value of critical habitat as a whole for the 
conservation of a listed 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. 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, authorized, or carried out by a Federal

[[Page 23633]]

agency--do not require section 7 consultation.
    Compliance with the requirements of section 7(a)(2) of the Act is 
documented 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 and 
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 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 Service 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 set forth requirements for Federal 
agencies to reinitiate formal consultation on previously reviewed 
actions. These requirements apply when the Federal agency has retained 
discretionary involvement or control over the action (or the agency's 
discretionary involvement or control is authorized by law) and, 
subsequent to the previous consultation, we have listed a new species 
or designated critical habitat that may be affected by the Federal 
action, or the action has been modified in a manner that affects the 
species or critical habitat in a way not considered in the previous 
consultation. In such situations, Federal agencies sometimes may need 
to request reinitiation of consultation with us, but the regulations 
also specify some exceptions to the requirement to reinitiate 
consultation on specific land management plans after subsequently 
listing a new species or designating new critical habitat. See the 
regulations for a description of those exceptions.

Application of the ``Adverse Modification'' Standard

    The key factor related to the destruction or adverse modification 
determination is whether implementation of the proposed Federal action 
directly or indirectly alters the designated critical habitat in a way 
that appreciably diminishes the value of the critical habitat as a 
whole for the conservation of the listed species. As discussed above, 
the role of critical habitat is to support physical or biological 
features essential to the conservation of a listed 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 violate 7(a)(2) 
of the Act by destroying or adversely modifying such habitat, or that 
may be affected by such designation.
    Activities that the Services may, during a consultation under 
section 7(a)(2) of the Act, find are likely to destroy or adversely 
modify critical habitat 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: Poorly managed 
livestock grazing; 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 northern Mexican gartersnake 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 exceedances 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.
    (4) Actions that would remove, diminish, or significantly alter the 
structural complexity of key natural structural habitat features in and 
adjacent to aquatic habitat. These features may be organic or 
inorganic, may be natural or constructed, 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, shelter, protection from predators, 
and foraging opportunities.

[[Page 23634]]

    (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; 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 predatory 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 pathogens such as 
Batrachochytrium dendrobatidis, which is a serious threat to the 
amphibian prey base of northern Mexican gartersnakes. Possible actions 
could include, but are not limited to: Introducing or stocking 
nonnative, spiny-rayed fishes, bullfrogs, crayfish, tiger salamanders, 
or other predators of 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 predatory nonnative species within a watershed; 
constructing water diversions, canals, or other water conveyances that 
move water from one place to another and through which inadvertent 
transport of predatory nonnative species into northern Mexican or 
narrow-headed gartersnake habitat may occur; and moving water, mud, wet 
equipment, or vehicles from one aquatic site to another, through which 
inadvertent transport of pathogens may occur. These activities directly 
or indirectly cause unnatural competition with and predation from 
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 narrow-headed 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 narrow-headed 
gartersnake population.

Exemptions

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

    Section 4(a)(3)(B)(i) of the Act (16 U.S.C. 1533(a)(3)(B)(i)) 
provides that: ``The Secretary shall not designate as critical habitat 
any lands or other geographical areas owned or controlled by the 
Department of Defense, or designated for its use, that are subject to 
an integrated natural resources management plan [INRMP] 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 designation.

Exclusions

Consideration of Impacts Under 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 
impact 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 the determination to exclude a particular area, 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.
    The first sentence in section 4(b)(2) of the Act requires that we 
take into consideration the economic, national security or other 
relevant impacts of designating any particular area as critical 
habitat. We describe below the process that we undertook for taking 
into consideration each category of impacts and our analyses of the 
relevant impacts.
Consideration of Economic Impacts
    Section 4(b)(2) of the Act and its implementing regulations require 
that we consider the economic impact that may result from a designation 
of critical habitat. To assess the probable economic impacts of a 
designation, we must first evaluate specific land uses or activities 
and projects that may occur in the area of the critical habitat. We 
then must evaluate the impacts that a specific critical habitat 
designation may have on restricting or modifying specific land uses or 
activities for the benefit of the species and its habitat within the 
areas proposed. We then identify which conservation efforts may be the 
result of the species being listed under the Act versus those 
attributed solely to the designation of critical habitat for this 
particular species. The probable economic impact of a proposed critical 
habitat designation is analyzed by comparing scenarios both ``with 
critical habitat'' and ``without critical habitat.'' The ``without 
critical habitat'' scenario represents the baseline for the analysis, 
which includes the existing regulatory and socio-economic burden 
imposed on landowners, managers, or other resource users potentially 
affected by the designation of critical habitat (e.g., under the 
Federal listing as well as other Federal, State, and local 
regulations). The baseline, therefore, represents the costs of all 
efforts attributable to the listing of the species under the Act (i.e., 
conservation of the species and its habitat incurred regardless of 
whether critical habitat is designated). The ``with critical habitat'' 
scenario describes the incremental impacts associated specifically with 
the designation of critical habitat for the species. The incremental 
conservation efforts and associated impacts would not be expected 
without the designation of critical habitat for the species. In other 
words, the incremental costs are those attributable solely to the 
designation of critical habitat, above and beyond the baseline costs. 
These are the costs we use when evaluating the benefits of inclusion 
and exclusion of particular areas from the final designation of 
critical habitat should we choose to conduct a discretionary 4(b)(2) 
exclusion analysis.
    For this particular designation, we developed an incremental 
effects memorandum (IEM) considering the probable incremental economic 
impacts that may result from this proposed

[[Page 23635]]

designation of critical habitat. The information contained in our IEM 
was then used to develop a screening analysis of the probable effects 
of the designation of critical habitat for the northern Mexican 
gartersnake and the narrow-headed gartersnake (Industrial Economics 
2019, entire). We began by conducting a screening analysis of the 
proposed designation of critical habitat in order to focus our analysis 
on the key factors that are likely to result in incremental economic 
impacts. The purpose of the screening analysis is to filter out the 
geographic areas in which the critical habitat designation is unlikely 
to result in probable incremental economic impacts. In particular, the 
screening analysis considers baseline costs (i.e., absent critical 
habitat designation) and includes probable economic impacts where land 
and water use may be subject to conservation plans, land management 
plans, best management practices, or regulations that protect the 
habitat area as a result of the Federal listing status of the species. 
The screening analysis filters out particular areas of critical habitat 
that are already subject to such protections and are, therefore, 
unlikely to incur incremental economic impacts. Ultimately, the 
screening analysis allows us to focus our analysis on evaluating the 
specific areas or sectors that may incur probable incremental economic 
impacts as a result of the designation. The screening analysis also 
assesses whether units are unoccupied by the species and may require 
additional management or conservation efforts as a result of the 
critical habitat designation for the species which may incur 
incremental economic impacts. This screening analysis, combined with 
the information contained in our IEM, are what we consider our draft 
economic analysis (DEA) of the proposed critical habitat designation 
for the northern Mexican gartersnake and the narrow-headed gartersnake. 
The DEA is summarized in the narrative below.
    Executive Orders (E.O.s) 12866 and 13563 direct Federal agencies to 
assess the costs and benefits of available regulatory alternatives in 
quantitative (to the extent feasible) and qualitative terms. Consistent 
with the E.O. regulatory analysis requirements, our effects analysis 
under the Act may take into consideration impacts to both directly and 
indirectly affected entities, where practicable and reasonable. If 
sufficient data are available, we assess to the extent practicable the 
probable impacts to both directly and indirectly affected entities. As 
part of our screening analysis, we considered the types of economic 
activities that are likely to occur within the areas likely affected by 
the critical habitat designation. In our evaluation of the probable 
incremental economic impacts that may result from the proposed 
designation of critical habitat for the northern Mexican gartersnake 
and the narrow-headed gartersnake, first we identified, in the IEM 
dated October 10, 2019, probable incremental economic impacts 
associated with the following categories of activities: (1) Federal 
lands management (National Park Service, U.S. Forest Service, Bureau of 
Land Management, Service, Department of Defense); (2) grazing (U.S. 
Forest Service, Bureau of Indian Affairs, Bureau of Land Management); 
(3) groundwater pumping (U.S. Forest Service, Bureau of Land 
Management, Department of Defense); (4) in-stream dams and diversions 
(Bureau of Land Management, Bureau of Reclamation, Service, Department 
of Defense); (5) dredging (Army Corps of Engineers, U.S. Forest 
Service, Bureau of Land Management, Natural Resources Conservation 
Service, National Park Service, Bureau of Indian Affairs); (6) water 
supply (Bureau of Reclamation, Army Corps of Engineers, Service, Bureau 
of Indian Affairs); (7) conservation and restoration (Natural Resources 
Conservation Service, Service, U.S. Forest Service, Department of 
Defense, Bureau of Land Management, National Park Service); (8) mining 
(U.S. Forest Service, Bureau of Land Management); (9) fire management 
(National Park Service, U.S. Forest Service, Bureau of Land Management, 
Bureau of Indian Affairs, Department of Defense); (10) vegetation and 
forest management (National Park Service, U.S. Forest Service, Bureau 
of Land Management); (11) transportation, including road and bridge 
construction and maintenance (Department of Transportation, Department 
of Defense, Bureau of Land Management, National Park Service, U.S. 
Forest Service, Customs and Border Protection, Bureau of Indian 
Affairs, Army Corps of Engineers); (12) recreation, including, but not 
limited to, sport fishing, sport-fish stocking, and off-highway vehicle 
use (National Park Service, U.S. Forest Service, Bureau of Land 
Management); (13) border protection and national security (U.S. Customs 
and Border Protection, Department of Defense); (14) renewable energy 
(Bureau of Indian Affairs, Department of Transportation, Bureau of Land 
Management); and (15) commercial or residential development (Army Corps 
of Engineers). We considered each industry or category individually. 
Additionally, we considered whether their activities have any Federal 
involvement. Critical habitat designation generally will not affect 
activities that do not have any Federal involvement; under the Act, 
designation of critical habitat only affects activities conducted, 
funded, permitted, or authorized by Federal agencies. In areas where 
the northern Mexican gartersnake or the narrow-headed gartersnake is 
present, Federal agencies already are required to consult with the 
Service under section 7 of the Act on activities they fund, permit, or 
implement that may affect the species. If we finalize this revised 
proposed critical habitat designation, consultations to avoid the 
destruction or adverse modification of critical habitat would be 
incorporated into the existing consultation process.
    In our IEM, we attempted to clarify the distinction between the 
effects that will result from the species being listed and those 
attributable to the critical habitat designation (i.e., difference 
between the jeopardy and adverse modification standards) for the 
northern Mexican gartersnake's and the narrow-headed gartersnake's 
critical habitat. The following specific circumstances help to inform 
our evaluation: (1) The essential physical or biological features 
identified for critical habitat are the same features essential for the 
life requisites of the species, and (2) any actions that would result 
in sufficient harm or harassment to constitute jeopardy to the northern 
Mexican gartersnake and the narrow-headed gartersnake would also likely 
adversely affect the essential physical or biological features of 
critical habitat. The IEM outlines our rationale concerning this 
limited distinction between baseline conservation efforts and 
incremental impacts of the designation of critical habitat for this 
species. This evaluation of the incremental effects has been used as 
the basis to evaluate the probable incremental economic impacts of this 
proposed designation of critical habitat.
    The proposed critical habitat designation for the northern Mexican 
gartersnake 27,784 ac (11,244 ha) comprising 9 units. Land ownership 
within proposed critical habitat for the northern Mexican gartersnake 
in acres is broken down as follows: Federal (62 percent), State 
(Arizona and New Mexico) (5 percent), Tribal (0.3 percent), and private 
(32 percent) (see table 2a, above). All units are considered occupied.
    The proposed critical habitat designation for the narrow-headed 
gartersnake 18,701 ac (7,568 ha)

[[Page 23636]]

comprising 8 units. Land ownership within proposed critical habitat for 
the narrow-headed gartersnake in acres is broken down as follows: 
Federal (66 percent), State (Arizona and New Mexico) (2 percent), 
Tribal (3 percent), and private (29 percent) (see table 2b, above). All 
units are considered occupied.
    In these areas, any actions that may affect the species would also 
affect designated critical habitat because the species is so dependent 
on habitat to fulfill its life-history functions. Therefore, any 
conservation measures to address impacts to the species would be the 
same as those to address impacts to critical habitat. Consequently, it 
is unlikely that any additional conservation efforts would be 
recommended to address the adverse modification standard over and above 
those recommended as necessary to avoid jeopardizing the continued 
existence of the both gartersnakes. Further, every unit of proposed 
critical habitat overlaps with the ranges of a number of currently 
listed species and designated critical habitats. Therefore, the actual 
number of section 7 consultations is not expected to increase at all. 
The consultation would simply have to consider an additional species or 
critical habitat unit. While this additional analysis will require time 
and resources by the Federal action agency, the Service, and third 
parties, the probable incremental economic impacts of the critical 
habitat designation are expected to be limited to additional 
administrative costs and would not be significant (Industrial Economics 
2019, entire). This is due to all units being occupied by either the 
northern Mexican gartersnake or the narrow-headed gartersnake.
    Based on consultation history for the gartersnakes, the number of 
future consultations, including technical assistances, is likely to be 
no more than 21 per year. The additional administrative cost of 
addressing adverse modification in these consultations is likely to be 
less than $61,000 in a given year, including costs to the Service, the 
Federal action agency, and third parties (Industrial Economics 2019 p. 
14), with approximately $28,000 for formal consultations, $32,000 for 
informal consultations, and $1,100 for technical assistances. This is 
based on an individual technical assistance costing $410, informal 
consultation costing $2,500, and formal consultation costing $9,600. 
Therefore, the incremental costs associated with critical habitat are 
unlikely to exceed $100 million in any single year and, therefore, 
would not be significant.
    To predict which units of proposed critical habitat are likely to 
experience the highest estimated incremental costs, we consider both 
the geographic distribution of historical formal consultations as well 
as the geographic distribution of land area. The units with the most 
historical formal consultations as well as the most acres of proposed 
critical habitat--and therefore the highest probability of intersecting 
with projects or activities with a Federal nexus that require 
consultation--are most likely to result in the highest incremental 
costs. Based on these criteria, Units 3 and 9 for the northern Mexican 
gartersnake are likely to result in the highest costs, with 30 percent 
and 15 percent of the 5.4 annual formal consultations occurring 
respectively in these units (Industrial Economics 2019, p. 16). In Unit 
3, this would result in a cost of approximately $15,500; of this, the 
third-party cost is estimated to be less than 20 percent, or 
approximately $3,100. In Unit 9, this would result in a cost of 
approximately $7,700; of this, the third-party cost is estimated to be 
less than 20 percent, or approximately $1,500.
    For the narrow-headed gartersnake, Units 1 and 2 are likely to 
result in the highest costs, with 6 percent and 11 percent of the 5.4 
annual formal consultations occurring respectively in these units 
(Industrial Economics 2019, p. 17). In Unit 1, this would result in a 
cost of approximately $3,100; of this, the third-party cost is 
estimated to be less than 20 percent, or approximately $600. In Unit 2, 
this would result in a cost of approximately $5,700; of this, the 
third-party cost is estimated to be less than 20 percent, or 
approximately $1,100. Therefore, impacts that are concentrated in any 
geographic area or sector would not be likely because of this critical 
habitat designation.
    As we stated earlier, we are soliciting data and comments from the 
public on the draft economic analysis, as well as all aspects of this 
revised proposed rule and our required determinations. We may revise 
the proposed rule or supporting documents to incorporate or address 
information we receive during the public comment period. In particular, 
we may exclude an area from critical habitat if we determine that the 
benefits of excluding the area outweigh the benefits of including the 
area, provided the exclusion will not result in the extinction of this 
species.
    During the development of a final designation, we will consider any 
additional economic impact information we receive through the public 
comment period, and as such 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 Economic Impacts

    The first sentence of section 4(b)(2) of the Act requires the 
Service to consider the economic impacts (as well as the impacts on 
national security and any other relevant impacts) of designating 
critical habitat. In addition, economic impacts may, for some 
particular areas, play an important role in the discretionary 4(b)(2) 
exclusion analysis under the second sentence of section 4(b)(2). In 
both contexts, the Service will consider the probable incremental 
economic impacts of the designation. When the Service undertakes a 
discretionary 4(b)(2) exclusion analysis with respect to a particular 
area, we will weigh the economic benefits of exclusion (and any other 
benefits of exclusion) against any benefits of inclusion (primarily the 
conservation value of designating the area). The conservation value may 
be influenced by the level of effort needed to manage degraded habitat 
to the point where it could support the listed species. The Service 
will use its discretion in determining how to weigh probable 
incremental economic impacts against conservation value. The nature of 
the probable incremental economic impacts and not necessarily a 
particular threshold level triggers considerations of exclusions based 
on probable incremental economic impacts. For example, if an economic 
analysis indicates high probable incremental impacts of designating a 
particular critical habitat unit of low conservation value (relative to 
the remainder of the designation), the Services may consider exclusion 
of that particular unit.

Considerations Based on National Security Impacts

    Section 4(a)(3)(B)(i) of the Act may not cover all Department of 
Defense (DoD) lands or areas that pose potential national-security 
concerns (e.g., a DoD installation that is in the process of revising 
its INRMP for a newly listed species or a species previously not 
covered). If a particular area is not covered under section 
4(a)(3)(B)(i), national-security or homeland-security concerns are not 
a factor in the process of determining what areas meet the definition 
of ``critical habitat.'' Nevertheless, when designating critical 
habitat under section 4(b)(2), the Service must consider impacts on 
national security, including homeland security, on lands or areas not 
covered by section

[[Page 23637]]

4(a)(3)(B)(i). Accordingly, we will always consider for exclusion from 
the designation areas for which DoD, Department of Homeland Security 
(DHS), or another Federal agency has requested exclusion based on an 
assertion of national-security or homeland-security concerns.
    We cannot automatically exclude requested areas. When DoD, DHS, or 
another Federal agency requests exclusion from critical habitat on the 
basis of national-security or homeland-security impacts, it must 
provide a reasonably specific justification of an incremental impact on 
national security that would result from the designation of that 
specific area as critical habitat. That justification could include 
demonstration of probable impacts, such as impacts to ongoing border-
security patrols and surveillance activities, or a delay in training or 
facility construction, as a result of compliance with section 7(a)(2) 
of the Act. If the agency requesting the exclusion does not provide us 
with a reasonably specific justification, we will contact the agency to 
recommend that it provide a specific justification or clarification of 
its concerns relative to the probable incremental impact that could 
result from the designation. If the agency provides a reasonably 
specific justification, we will defer to the expert judgment of DoD, 
DHS, or another Federal agency as to: (1) Whether activities on its 
lands or waters, or its activities on other lands or waters, have 
national-security or homeland-security implications; (2) the importance 
of those implications; and (3) the degree to which the cited 
implications would be adversely affected in the absence of an 
exclusion. In that circumstance, in conducting a discretionary 4(b)(2) 
exclusion analysis, we will give great weight to national-security and 
homeland-security concerns in analyzing the benefits of exclusion.
    Congress has provided to the Secretary of Homeland Security a 
number of authorities necessary to carry out the Department's border 
security mission. One of those authorities is found at section 102 of 
the Illegal Immigration Reform and Immigrant Responsibility Act of 
1996, as amended (``IIRIRA''). In section 102(a) of IIRIRA, Congress 
provided that the Secretary of Homeland Security shall take such 
actions as may be necessary to install additional physical barriers and 
roads (including the removal of obstacles to detection of illegal 
entrants) in the vicinity of the United States border to deter illegal 
crossings in areas of high illegal entry into the United States. In 
section 102(b) of IIRIRA, Congress mandated the installation of 
additional fencing, barriers, roads, lighting, cameras, and sensors on 
the southwest border. Finally, in section 102(c) of IIRIRA, Congress 
granted to the Secretary of Homeland Security the authority to waive 
all legal requirements that he determines are necessary to ensure the 
expeditious construction of barriers and roads authorized by section 
102 of IIRIRA. On May 15, 2019, the Secretary of Homeland Security 
issued waivers for legal requirements covering border barrier 
activities directly in the vicinity of the garternsnakes' known range 
and proposed critical habitat (84 FR 21798).

Exclusions Based on National Security Impacts

    We received comments from the U.S. Army installation at Fort 
Huachuca requesting that we exclude from the final designation of 
critical habitat the San Pedro River and Babocomari River subunits 
within the San Pedro River Subbasin Unit that fall within the San Pedro 
Riparian National Conservation Area (SPRNCA) managed by the BLM, as 
well as the lands owned by the Arizona State Land Department and 
private landowners. This includes 92 percent of the San Pedro River 
Subunit and all of the Babocomari River Subunit.
San Pedro River Subunit and Babocomari River Subunit
    The area being requested for exclusion is part of the SPRNCA and is 
managed by the BLM and comprised of Federal, State, and private lands. 
The Army's rationale for the exclusion was that any additional 
restrictions to ground-water pumping and water usage could affect their 
ability to increase staffing when needed, or carry out missions 
critical to national security. The Army also stated that designation of 
lands within the SPRNCA would increase its regulatory burden and 
disrupt its operations related to national security. The Army pointed 
to its continued land stewardship actions and its commitment to 
protecting natural resources on the base. We are considering this area 
for exclusion based on impacts to national security.

Considerations of Other Relevant Impacts

    When identifying the benefits of inclusion for an area, we consider 
the additional regulatory benefits that area would receive due to the 
protection from destruction of adverse modification 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 considering the benefits of exclusion, we consider, among 
other things, whether exclusion of a specific area is likely to result 
in conservation, or in the continuation, strengthening, or 
encouragement of partnerships.
    In the case of northern Mexican and narrow-headed gartersnakes, the 
benefits of critical habitat include public awareness of the presence 
of northern Mexican and narrow-headed gartersnakes and the importance 
of habitat protection, and, where a Federal nexus exists, increased 
habitat protection for northern Mexican and narrow-headed gartersnakes 
due to protection from destruction or adverse modification of critical 
habitat. Additionally, continued implementation of an ongoing 
management plan that provides equal to or more conservation than a 
critical habitat designation would reduce the benefits of including 
that specific area in the critical habitat designation.
    We evaluate the existence of a conservation plan when considering 
the benefits of inclusion. We consider 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 of the species. If exclusion of an area from critical 
habitat will result in extinction, we will not exclude it from the 
designation.

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

[[Page 23638]]

whether there are permitted conservation plans covering the species in 
the area such as HCPs, safe harbor agreements, or candidate 
conservation agreements with assurances, or whether there are non-
permitted conservation agreements and partnerships that would be 
encouraged by designation of, or exclusion from, critical habitat. In 
addition, we look at the existence of tribal conservation plans and 
partnerships 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.
    Based on the information provided by entities seeking exclusion, as 
well as any additional public comments we receive, we will evaluate 
whether any lands in the proposed critical habitat areas are 
appropriate for exclusion from the final designation under 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.
Private or Other Non-Federal Conservation Plans or Agreements and 
Partnerships, in General
    We sometimes exclude specific areas from critical habitat 
designations based in part on the existence of private or other non-
Federal conservation plans or agreements and their attendant 
partnerships. A conservation plan or agreement describes actions that 
are designed to provide for the conservation needs of a species and its 
habitat, and may include actions to reduce or mitigate negative effects 
on the species caused by activities on or adjacent to the area covered 
by the plan. Conservation plans or agreements can be developed by 
private entities with no Service involvement, or in partnership with 
the Service.
    We evaluate a variety of factors to determine how the benefits of 
any exclusion and the benefits of inclusion are affected by the 
existence of private or other non-Federal conservation plans or 
agreements and their attendant partnerships when we undertake a 
discretionary 4(b)(2) exclusion analysis. A non-exhaustive list of 
factors that we will consider for non-permitted plans or agreements is 
shown below. These factors are not required elements of plans or 
agreements, and all items may not apply to every plan or agreement.
    (i) The degree to which the plan or agreement provides for the 
conservation of the species or the essential physical or biological 
features (if present) for the species;
    (ii) Whether there is a reasonable expectation that the 
conservation management strategies and actions contained in a 
management plan or agreement will be implemented;
    (iii) The demonstrated implementation and success of the chosen 
conservation measures;
    (iv) The degree to which the record of the plan supports a 
conclusion that a critical habitat designation would impair the 
realization of benefits expected from the plan, agreement, or 
partnership;
    (v) The extent of public participation in the development of the 
conservation plan;
    (vi) The degree to which there has been agency review and required 
determinations (e.g., State regulatory requirements), as necessary and 
appropriate;
    (vii) Whether National Environmental Policy Act (NEPA; 42 U.S.C. 
4321 et seq.) compliance was required; and
    (viii) Whether the plan or agreement contains a monitoring program 
and adaptive management to ensure that the conservation measures are 
effective and can be modified in the future in response to new 
information.
    We are considering exclusions related to the following non-
permitted (e.g., no safe harbor agreement or habitat conservation plan 
under the Act) voluntary plans that afford some protections to one or 
both gartersnakes species: The AGFD management plans for Bubbling Ponds 
and Page Springs State Fish Hatcheries and for Planet Ranch 
Conservation and Wildlife Area, and Freeport McMoRan Corporation 
management plans for spikedace and loach minnow. We also recognize our 
strong conservation partner in The Nature Conservancy, who manages 
exclusively for native aquatic species on their properties but do not 
have conservation management plans in place, per se.
AGFD Management Plans
    The AGFD owns lands included in proposed critical habitat for 
northern Mexican gartersnake within the Oak Creek Subunit (142 ac (57 
ha)) in the Verde River Subbasin Unit, and within the Bill Williams 
River Subunit (329 ac (133 ha)) in the Bill Williams River Subbasin 
Unit. The AGFD has implemented management actions at its Bubbling Ponds 
and Page Springs State Fish Hatcheries that benefit northern Mexican 
gartersnakes, including research on home range and habitat use of the 
species, maintaining fallow ponds as habitat for the species, and 
creating new gartersnake ponds as funds become available (Jones 2019). 
The AGFD also has an operational management plan for the Planet Ranch 
Conservation and Wildlife Area that they acquired in 2015 (AGFD 2018, 
entire). This property is along the Bill Williams River and within the 
Bill Williams River subunit of proposed critical habitat for northern 
Mexican gartersnake. The operational management plan includes habitat 
improvements that will be implemented and funded by the Lower Colorado 
River Multi-Species Conservation Program described above that could 
benefit the northern Mexican gartersnake (AGFD 2018, pp. 12-18). In 
addition, AGFD has a fully funded gartersnake biologist and has drafted 
a ``Gartersnake Research and Management Strategy'' for Arizona (Cotten 
et al. 2014, entire).
Freeport McMoRan Corporation (FMC) Management Plans
    The FMC currently has a management plan that focuses on 
conservation for listed spikedace and loach minnow on the middle 
section of the upper Gila River that confers benefits to northern 
Mexican and narrow-headed gartersnakes (FMC 2011, p. 7). Freeport 
McMoRan owns 515 ac (208 ha) of proposed critical habitat for northern 
Mexican gartersnake on the Gila River and Duck Creek in the Upper Gila 
River Subbasin Unit, and 563 ac (228 ha) of proposed critical habitat 
for narrow-headed gartersnakes on the Gila River in the Gila River 
Subbasin Unit that are included in this management plan. Here, FMC 
manages more than 7.2 mi (11.6 km) along this section of the Gila 
River, much of which is owned by the Pacific Western Land Company 
(PWLC), a subsidiary of FMC, and is included in the U-Bar Ranch. FMC's 
land and water rights in the Gila/Cliff Valley support operations at 
the Tyrone Mine in addition to its agricultural operations along the 
Gila River. Under FMC's existing management system, the riparian zone 
adjacent to the Gila River has expanded in width, benefitting the 
endangered southwestern willow flycatcher and other riparian species 
including the two gartersnakes. Surveys show that there are low levels 
of nonnative fishes in the Gila/Cliff Valley segment of the Gila River 
stream reach as well. Specific conservation measures in the Gila River 
Subbasin Unit of critical habitat that confer protections to both 
gartersnakes include a voluntary water conservation program in which 
FMC has enrolled 1,450 cubic feet per second (cfs) (2,876 ac-ft) of its 
annual average diversion rights through 2018, and maintenance of a 
minimum of 25

[[Page 23639]]

cfs (18,099 ac-ft per year) flow levels in the Gila River during 
periods of drought (FMC 2011, p. 10)
The Nature Conservancy
    The Nature Conservancy owns three properties that include 597 ac 
(242 ha) of proposed critical habitat for northern Mexican gartersnake 
in Arizona. These properties include the Verde Valley Preserve with 16 
ac (6 ha) of proposed critical habitat for northern Mexican gartersnake 
in the Verde River subunit, Canelo Hills Cienega Preserve with 1.8 ac 
(0.7 ha) of the O'Donnell Canyon Subunit, and the Patagonia-Sonoita 
Creek Preserve with 123 ac (50 ha) of the Sonoita Creek Subunit. The 
Nature Conservancy manages these properties for the benefit of aquatic 
and riparian species, although not all of them have management plans.

Private or Other Non-Federal Conservation Plans Related to Permits 
Under Section 10 of the Act

    HCPs for incidental take permits under section 10(a)(1)(B) of the 
Act provide for partnerships with non-Federal entities to minimize and 
mitigate impacts to listed species and their habitat. In some cases, 
HCP permittees agree to do more for the conservation of the species and 
their habitats on private lands than designation of critical habitat 
would provide alone. We place great value on the partnerships that are 
developed during the preparation and implementation of HCPs.
    Candidate conservation agreements with assurances (CCAAs) and safe 
harbor agreements (SHAs) are voluntary agreements designed to conserve 
candidate and listed species, respectively, on non-Federal lands. In 
exchange for actions that contribute to the conservation of species on 
non-Federal lands, participating property owners are covered by an 
``enhancement of survival'' permit under section 10(a)(1)(A) of the 
Act, which authorizes incidental take of the covered species that may 
result from implementation of conservation actions, specific land uses, 
and, in the case of SHAs, the option to return to a baseline condition 
under the agreements. The Service also provides enrollees assurances 
that we will not impose further land-, water-, or resource-use 
restrictions, or require additional commitments of land, water, or 
finances, beyond those agreed to in the agreements.
    When we undertake a discretionary 4(b)(2) exclusion analysis, we 
will always consider areas covered by an approved CCAA/SHA/HCP, and 
generally exclude such areas from a designation of critical habitat if 
three conditions are met:
    1. The permittee is properly implementing the CCAA/SHA/HCP, and is 
expected to continue to do so for the term of the agreement. A CCAA/
SHA/HCP is properly implemented if the permittee is, and has been, 
fully implementing the commitments and provisions in the CCAA/SHA/HCP, 
implementing agreement, and permit.
    2. The species for which critical habitat is being designated is a 
covered species in the CCAA/SHA/HCP, or very similar in its habitat 
requirements to a covered species. The recognition that the Services 
extend to such an agreement depends on the degree to which the 
conservation measures undertaken in the CCAA/SHA/HCP would also protect 
the habitat features of the similar species.
    3. The CCAA/SHA/HCP specifically addresses the habitat of the 
species for which critical habitat is being designated and meets the 
conservation needs of the species in the planning area.
    We are aware of the following plans related to permits under 
section 10 of the Act that fulfill the above criteria, and are 
considering the exclusion of non-Federal lands covered by these plans 
that provide for the conservation of northern Mexican or narrow-headed 
gartersnakes from the final designation: AGFD's SHA for topminnow and 
desert pupfish in Arizona (AGFD and USFWS 2007), AGFD's SHA for 
Chiricahua leopard frog in Arizona (AGFD and USFWS 2006), Lower 
Colorado River Multi-Species HCP (Lower Colorado Multi-Species 
Conservation Program 2018), Pima County Multi-Species HCP (Pima County 
2016), Salt River Project (SRP) Roosevelt HCP (SRP 2002) and Horseshoe-
Bartlett HCP (SRP 2008), and San Rafael Ranch Low-effect HCP (Harlow 
2015).
AGFD's SHA for Topminnow and Desert Pupfish in Arizona
    Signed in 2007, the AGFD's SHA for topminnow and desert pupfish is 
an umbrella document under which individual landowners in the entire 
Arizona range of these native fish species on non-Federal and tribal 
lands may participate. Topminnow and desert pupfish are prey species of 
the northern Mexican gartersnake. Three private landowners within the 
range of the northern Mexican gartersnake hold certificates of 
inclusion in this SHA: San Rafael Cattle Company for the 18,365-acre 
(7,482-ha) San Rafael Ranch in the San Rafael Valley, a private rancher 
for a <1 acre (<2.5 ha) property in the San Rafael Valley, and National 
Audubon Society for <1 acre (<2.5 ha) of the Appleton-Whittell Research 
Ranch. The San Rafael Cattle Company maintains permanent water in 44 
earthen stocktanks on the San Rafael Ranch that also serve as habitat 
for native aquatic species. The private rancher maintains permanent 
water in an earthen pond on his property that serves as habitat for 
native aquatic species. Appleton-Whittell Research Ranch is managed for 
the benefit of native species through a cooperative partnership among 
the National Audubon Society, U.S. Forest Service (USFS), BLM, The 
Nature Conservancy, Swift Current Land & Cattle Co., LLC, and the 
Research Ranch Foundation.
    There are 116 ac (47 ha) of private lands on the San Rafael Ranch 
and 0.1 ac (<0.1 ha) of private lands on the second private ranch 
included in proposed critical habitat for the northern Mexican 
gartersnake within the Upper Santa Cruz River Subbasin Unit. There are 
214 ac (87 ha) of private lands within Appleton-Whittell Research Ranch 
that are proposed as critical habitat for northern Mexican gartersnake 
within the Upper San Pedro River Subbasin Unit. Details of subunit 
breakdown are in table 2a, above. San Rafael Cattle Company, the second 
private rancher, and Audubon Research Ranch must maintain aquatic 
habitats free of nonnative predators, including bullfrogs and warmwater 
sportfish, in accordance with each certificate of inclusion. To date, 
Gila topminnow have been released into two stock tanks on the San 
Rafael Ranch, and desert pupfish have been released into a wildlife 
pond on the Appleton-Whittell Research Ranch. All of these sites also 
provide habitat for northern Mexican gartersnake.
AGFD's SHA for Chiricahua Leopard Frog in Arizona
    Signed in 2006, the AGFD SHA for Chiricahua leopard frog is an 
umbrella document under which individual landowners in the entire 
Arizona range of this species on non-Federal and tribal lands may 
participate. Chiricahua leopard frogs are a primary prey species of the 
northern Mexican gartersnake. Four private landowners within the range 
of the northern Mexican gartersnake hold certificates of inclusion in 
this SHA: San Rafael Cattle Company, The Nature Conservancy, National 
Audubon Society, and an additional private ranch. Under each 
certificate of inclusion in the SHA, the four landowners must maintain 
aquatic habitats free of nonnative predators, including bullfrogs and 
warmwater sportfish. The San Rafael Cattle

[[Page 23640]]

Company holds a certificate of inclusion for two pastures on 2,673 ac 
of the San Rafael Ranch in the San Rafael Valley. There are 5 ac (2 ha) 
within one of these pastures included in the unnamed drainage and 
Pasture 9 Tank subunit of proposed critical habitat for northern 
Mexican gartersnake in the Upper Santa Cruz River Subunit. This area is 
also covered by the San Rafael Ranch HCP, which is described below. To 
date, Chiricahua leopard frogs have been released into one stock tank 
on the San Rafael Ranch that also provides habitat for northern Mexican 
gartersnakes. This is in addition to the stock tank where Gila 
topminnows have been released on the ranch.
    National Audubon Society holds a certificate of inclusion for 1,409 
ac on the Appleton-Whittell Research Ranch. There are 191 ac (77 ha) on 
this property included in O'Donnell Canyon, Post Canyon, and Unnamed 
drainage & Finley Tank subunits of proposed critical habitat for 
northern Mexican gartersnake. To date, Chiricahua leopard frogs have 
been released into two locations on this property that also provide 
habitat for northern Mexican gartersnakes.
    Another private rancher a holds a certificate of inclusion for 79 
ac (32 ha) on lands adjacent to the Appleton-Whittell Research Ranch. 
There are 15 ac (6 ha) within this ranch included in the Post Canyon 
Subunit of proposed critical habitat for the northern Mexican 
gartersnake.
    The Nature Conservancy holds a certificate of inclusion for its 
Ramsey Canyon Preserve in Ramsey Canyon, which is adjacent to proposed 
critical habitat for the gartersnake in the House Pond Subunit. Both 
Ramsey Canyon Preserve and House Pond are occupied by a Chiricahua 
leopard frog metapopulation that is likely prey for the northern 
Mexican gartersnake in this area. Although the gartersnake has yet to 
be detected in Ramsey Canyon, it is currently extant in House Pond 
Subunit in Brown Canyon, the canyon immediately north of Ramsey Canyon.
Lower Colorado River Multi-Species HCP
    The Lower Colorado River Multi-species Conservation Program (LCR 
MSCP) is a joint effort by 6 Federal agencies, 3 States, 6 Tribes, 36 
cities, and water and power authorities with management authority for 
storage, delivery, and diversion of water; hydropower generation, 
marketing, and delivery; and land management or Native American Trust 
responsibilities along 400 mi (644 km) of the Lower Colorado River. In 
2005, the Service issued a 50-year incidental take permit to the Bureau 
of Reclamation to address take of 6 species listed under the Act and 21 
other species from water delivery and power generation along the Lower 
Colorado River. At this time, the northern Mexican gartersnake was 
considered extirpated from the lower Colorado River and is not included 
in the LCR MSCP. In 2018, the Bureau of Reclamation amended the LCR 
MSCP to address effects to the northern Mexican gartersnake, which was 
subsequently found in 2015 at Beal Lake on Havasu National Wildlife 
Refuge (NWR), which is included in the permit area. The LCR MSCP 
includes conservation measures to avoid and minimize direct effects of 
implementing covered activities and the LCR MSCP on the northern 
Mexican gartersnake, and the potential effects of habitat loss expected 
to be minimized with the creation of 1,496 ac (605 ha) of replacement 
habitat. Lands within the Lower Colorado River Unit are covered by the 
LCR MSCP, but are all Federal lands and are not proposed for exclusion 
from critical habitat designation. However, conservation measures also 
include funding for habitat improvements on Planet Ranch within the 
Bill Williams River Subunit that could benefit the northern Mexican 
gartersnake.
Pima County Sonoran Desert Conservation Plan and Multi-Species HCP
    Through its Sonoran Desert Conservation Plan (SDCP), Pima County, 
Arizona, has been implementing measures that benefit the northern 
Mexican gartersnake since 2001. In 2016, the Service issued a 30-year 
incidental take permit for the Pima County Multi-Species Habitat 
Conservation Plan (MSHCP) to address incidental take from residential 
and non-residential development, renewable energy projects, relocation 
of utilities, ranch-management activities, recreation, and conservation 
and mitigation activities. The MSHCP is part of the SDCP and addresses 
44 species, including the northern Mexican gartersnake. Under the SDCP 
and MSCP, Pima County manages lands that fall within proposed critical 
habitat for the northern Mexican gartersnake. There are 12 mi (19 km) 
of Cienega Creek within 543 ac (220 ha) of proposed critical habitat 
for northern Mexican gartersnake within the Cienega Creek Subunit of 
the Cienega Creek Subbasin Unit. The 3,797-acre Cienega Creek Natural 
Preserve is owned by the Pima County Flood Control District and is 
protected as a ``unique riparian ecosystem'' by a declaration of 
restrictions, covenants, and conditions by the Pima County Board of 
Supervisors in 1987 (Pima County Flood Control District 1987, p. 1). 
Management objectives of this preserve include preservation and 
protection of the perennial stream flow and existing riparian 
vegetation of Cienega Creek and its associated floodplain (Pima County 
Department of Transportation and Flood Control District 1994, p. 2-1). 
Protections to northern Mexican gartersnakes on this property exists 
through chapter 30 of title 16 of the Pima County Floodplain Management 
Ordinance (Pima County Code Ordinance Number 2010-FC5). Chapter 30 of 
the Floodplain Management Ordnance effectively minimizes habitat loss 
for northern Mexican gartersnake by protecting riparian habitat from 
development and requiring mitigation for disturbances to riparian 
habitat that exceed one-third of an acre. Pima County requested that 
lands within the Cienega Creek Natural Preserve remain in critical 
habitat for the northern Mexican gartersnake.
Salt River Project Roosevelt and Horseshoe-Bartlett HCPs
    In 2003, the Service issued an incidental take permit for the SRP 
Roosevelt HCP (SRP 2002) to address incidental take from operation of 
Roosevelt Dam and Lake for four riparian bird species, including 
southwestern willow flycatcher, bald eagle, Yuma clapper rail, and 
western yellow-billed cuckoo. As part of its mitigation measures for 
these bird species under the Roosevelt HCP, SRP has acquired and will 
manage in perpetuity 471 ac (191 ha) of riparian and adjacent upland 
habitat offsite along the Gila and Verde Rivers, some of which may also 
confer benefits to the two gartersnakes (SRP 2002, p. 143; SRP 2013, p. 
17).
    Subsequently in 2008, the Service issued another incidental take 
permit to SRP for the SRP Horseshoe-Bartlett HCP to address incidental 
take from the operation of Horseshoe and Bartlett reservoirs of listed 
species as well as both gartersnakes, which were not listed at the time 
of permit issuance. Mitigation measures in the Verde River watershed 
included in the Horseshoe-Bartlett HCP designed to benefit the two 
gartersnakes include reducing nonnative fish reproduction, recruitment, 
and movement at Horseshoe Reservoir; increasing native fish 
populations, distribution, and relative abundance in the Verde River; 
and working to maintain water flows in the Verde River above Horseshoe 
Reservoir through watershed management activities (SRP

[[Page 23641]]

2008, pp. 193-196). Mitigation also included acquisition and management 
in perpetuity of 50 ac (20 ha) of riparian habitat along the Verde 
River and 150 ac (61 ha) of riparian habitat offsite along the Gila 
River, some of which may benefit the two gartersnakes (SRP 2008, pp. 
179-184). Private lands, as well as acquisitions or conservation 
easements made to date for both of SRP's HCPs that fall within proposed 
critical habitat for northern Mexican gartersnake, include 515 ac (208 
ha) of private lands in the Gila River and Duck Creek subunits, and 96 
ac (39 ha) of private lands in the Verde River Subunit (SRP 2014, pp. 
27-30; SRP 2014a, p. 11). SRP-owned lands that fall within proposed 
critical habitat for narrow-headed gartersnake include 563 ac (228 ha) 
of the Gila River Subunit. Management actions on the Camp Verde 
Riparian Preserve property on the Verde River that may benefit the two 
gartersnakes include acquiring water rights; creating conservation 
easements; maintaining fencing around riparian areas, including log-
jams that allow normal hydrologic processes to continue unimpeded while 
excluding livestock; planting native species above riparian areas to 
improve watershed conditions; and monitoring groundwater and stream 
flow levels.
San Rafael Ranch Low-Effect HCP
    In 2016, the Service issued a 30-year incidental take permit for 
the San Rafael Ranch low-effect HCP (Harlow 2015) to address incidental 
take from cattle ranching operations of Sonoran tiger salamander, 
northern Mexican gartersnake, Gila chub, and Huachuca springsnail. 
Measures to minimize take emphasize the use of riparian pastures and 
dispersed grazing, maintaining existing and developing new livestock 
ponds that also serve as habitat for covered species including the 
northern Mexican gartersnake, and undertaking recovery actions for 
listed species in cooperation with the Service and AGFD. The incidental 
take permit boundary includes the 18,500-acre San Rafael Ranch. 
Portions of the Santa Cruz River, Unnamed drainage and Pasture 9 Tank, 
and Unnamed drainage and Sheehy Spring subunits (116 ac (47 ha)) of 
proposed critical habitat for northern Mexican gartersnake fall within 
the incidental take permit boundary. Implementation of winter grazing 
only in riparian pastures along the Santa Cruz River and managed 
grazing of upland pastures would maintain habitat for northern Mexican 
gartersnakes. Maintaining fencing and managing trespass cattle limits 
grazing of riparian pastures to the non-growing season and lessens 
impacts to proposed critical habitat. Maintenance of stock tanks will 
also help address nonnative predator populations in proposed critical 
habitat.

Tribal Lands

    Several Executive Orders, Secretarial Orders, and policies relate 
to working with Tribes. These guidance documents generally confirm our 
trust responsibilities to Tribes, recognize that Tribes have sovereign 
authority to control tribal lands, emphasize the importance of 
developing partnerships with tribal governments, and direct the Service 
to consult with Tribes on a government-to-government basis.
    A joint Secretarial Order that applies to both the Service and the 
National Marine Fisheries Service (NMFS), Secretarial Order 3206, 
American Indian Tribal Rights, Federal-Tribal Trust Responsibilities, 
and the Endangered Species Act (June 5, 1997) (S.O. 3206), is the most 
comprehensive of the various guidance documents related to tribal 
relationships and Act implementation, and it provides the most detail 
directly relevant to the designation of critical habitat. In addition 
to the general direction discussed above, S.O. 3206 explicitly 
recognizes the right of Tribes to participate fully in the listing 
process, including designation of critical habitat. The Order also 
states, ``Critical habitat shall not be designated in such areas unless 
it is determined essential to conserve a listed species. In designating 
critical habitat, the Services shall evaluate and document the extent 
to which the conservation needs of the listed species can be achieved 
by limiting the designation to other lands.'' In light of this 
instruction, when we undertake a discretionary 4(b)(2) exclusion 
analysis, we will always consider exclusions of tribal lands under 
section 4(b)(2) of the Act prior to finalizing a designation of 
critical habitat, and will give great weight to tribal concerns in 
analyzing the benefits of exclusion.
    However, S.O. 3206 does not preclude us from designating tribal 
lands or waters as critical habitat, nor does it state that tribal 
lands or waters cannot meet the Act's definition of ``critical 
habitat.'' We are directed by the Act to identify areas that meet the 
definition of ``critical habitat'' (i.e., areas occupied at the time of 
listing that contain the essential physical or biological features that 
may require special management or protection and unoccupied areas that 
are essential to the conservation of a species), without regard to 
landownership. While S.O. 3206 provides important direction, it 
expressly states that it does not modify the Secretaries' statutory 
authority.
Fort Apache Native Fish Management Plan
    The White Mountain Apache Tribe's Fort Apache Indian Reservation 
(Fort Apache) encompasses approximately 1,680,000 ac (679,872 ha) in 
east-central Arizona. Fort Apache includes 6 percent of the Black River 
Subbasin Unit (92 ac (37 ha)) and 33 percent of Canyon Creek Unit (77 
ac (31 ha)) of proposed critical habitat for narrow-headed gartersnake. 
The Salt River and Black River serve as the boundary between Fort 
Apache and the San Carlos Apache Reservations. In May 2014, the White 
Mountain Apache Tribe and the Service drafted a native fish's 
management plan for Fort Apache that includes the federally endangered 
loach minnow, federally threatened Apache trout, and four other native 
fish species currently extant on Fort Apache (White Mountain Apache 
Tribe and Service 2014, p. 2). This plan supersedes their 2000 Loach 
Minnow Management Plan (White Mountain Apache Tribe 2000, entire). The 
draft 2014 management plan identifies several Tribal regulation and 
management efforts they think are beneficial to loach minnow and would 
also confer benefits to the gartersnakes, including Resolution 89-149, 
which designates streams and riparian zones as Sensitive Fish and 
Wildlife areas, requiring that authorized programs ensure these zones 
remain productive for fish and wildlife. The White Mountain Apache 
Tribe additionally adopted a Water Quality Protection Ordinance in 1999 
to ``promote the health of Tribal waters and the people, plants and 
wildlife that depend on them through holistic management and 
sustainable use.'' The draft 2014 management plan also includes an 
objective to identify Native Fish Management Units within each of the 
watersheds on Fort Apache and develop initial management 
recommendations for each Native Fish Management Unit, considering 
native fish and aquatic and riparian obligates, including, but not 
limited to, species such as leopard frogs and gartersnakes (White 
Mountain Apache Tribe and AFWCO 2014, p. 21).
San Carlos Apache Tribe Fishery Management Plan
    The San Carlos Apache Reservation encompasses approximately 
1,850,000 ac (748,668 ha) in east-central Arizona. This reservation 
includes 6 percent (102 ac (41 ha)) of the Black River Subbasin Unit 
and 70 percent (236 ac (96 ha)) of the Eagle Creek Unit of proposed 
critical habitat for narrow-headed gartersnake.

[[Page 23642]]

The Salt River and Black River serve as the boundary between the San 
Carlos Apache Reservation and Fort Apache. The San Carlos Apache Tribe 
Fishery Management Plan (FMP; San Carlos Apache Tribe 2005, entire) was 
adopted in 2005, via Tribal Resolution SEP-05-178. This management plan 
addresses both sportfish and native fish management on the San Carlos 
Apache Reservation. Although sportfish have not been intentionally 
stocked in streams on the reservation since 1975, sportfish continue to 
be stocked in lentic waters including lakes, ponds, and stocktanks 
throughout the San Carlos Apache Reservation. The FMP has several goals 
relevant to native fish management, which may confer benefits to the 
gartersnakes by supporting conservation of their prey species. These 
goals include development and implementation of integrated, watershed-
based approaches to fishery resource management; conserving, enhancing, 
and maintaining existing native fish populations and their habitats as 
part of the natural diversity of the San Carlos Apache Reservation, and 
preventing, minimizing, or mitigating adverse impacts to all native 
fishes, especially threatened or endangered species, and their habitats 
when consistent with the Reservation as a permanent home and abiding 
place for San Carlos Apache Tribal members; restoring extirpated native 
fishes and degraded natural habitats when appropriate and economically 
feasible; increasing Tribal awareness of native fish conservation and 
values; and aggressively pursuing funding adequate to support all 
Tribal conservation and management activities for all native fishes and 
their habitats (San Carlos Apache Tribe 2005, pp. 63-71).
Yavapai-Apache Nation Tribal Resolution 46-2006
    The Yavapai-Apache Nation includes 207 ac (84 ha) of proposed 
critical habitat for northern Mexican gartersnake in the Verde River 
Subunit. Yavapai-Apache Nation approved Tribal Resolution 46-2006, 
``confirming and declaring a riparian conservation corridor and 
management plan for the Verde River'' that affords protections to both 
gartersnakes. This resolution requires the Yavapai-Apache Nation to 
``preserve the physical and biological features found within the 
riparian corridor of the Verde River essential to native wildlife 
species, including species listed as endangered or threatened by the 
federal government under the Endangered Species Act'' (Yavapai-Apache 
Nation 2006, p. 1). The riparian corridor is defined as a 300-ft (91-m) 
buffer from centerline of the Verde River on their lands (Yavapai-
Apache Nation 2006, p. 1). Within this corridor, the Yavapai-Apache 
resolves to coordinate with the Service on actions that may adversely 
impact habitat essential to the conservation and/or recovery of 
federally listed species (Yavapai-Apache Nation 2006, p. 2). In 
addition, stocking of nonnative fishes is specifically prohibited by 
the resolution (Yavapai-Apache Nation 2006, p. 2).
    We scheduled a meeting with these tribes and other interested 
tribes prior to publication of this revised proposed rule to give them 
as much time as possible to comment.

Summary of Exclusion We Are Considering

    Based on the information provided by entities seeking exclusion, as 
well as any additional public comments we receive, we will evaluate 
whether certain lands in the proposed critical habitat are appropriate 
for exclusion from the final designation under 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. The areas 
described above that we are considering excluding under section 4(b)(2) 
of the Act from the final critical habitat designation 7,405 ac (2,997 
ha) for northern Mexican gartersnake and 1,072 ac (434 ha) for narrow-
headed gartersnake, which represents 27 percent and 6 percent of the 
proposed designation for each gartersnake species, respectively. Tables 
3a and 3b, below, provide approximate areas (ac, ha) of lands that meet 
the definition of critical habitat for each gartersnake species but are 
under our consideration for possible exclusion under section 4(b)(2) of 
the Act from the final critical habitat rule. Additionally, we will 
consider excluding any other areas where we determine that the benefits 
of exclusion outweigh the benefits of inclusion based upon the 
information we have when we finalize a critical habitat designation.

 Table 3a--Areas Identified for Possible Exclusion for the Northern Mexican Gartersnake by Critical Habitat Unit
                                                   and Subunit
----------------------------------------------------------------------------------------------------------------
                                                                                                    Portion of
           Unit subunit              Landowner, property       Ownership type      Area in acres      unit or
                                             name                                   (hectares)        subunit
----------------------------------------------------------------------------------------------------------------
                                         Upper Gila River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Gila River........................  Freeport McMoRan       Private..............       500 (202)             48%
                                     (Freeport McMoRan
                                     Corporation
                                     management plans).
Duck Creek........................  Freeport McMoRan       Private..............          15 (6)             14%
                                     (Freeport McMoRan
                                     Corporation
                                     management plans).
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................       515 (208)             45%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                            Verde River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Verde River.......................  The Nature             Private..............          16 (6)            0.4%
                                     Conservancy, Verde
                                     Valley Preserve and
                                     Verde Valley
                                     property.
                                    Salt River Project,    Private..............         96 (39)              2%
                                     Camp Verde Riparian
                                     Preserve (Roosevelt
                                     and Horseshoe-
                                     Bartlett HCPs).
                                    Yavapai-Apache Nation  Tribal...............        207 (84)              5%
Oak Creek.........................  Arizona Game and Fish  State................        142 (57)             14%
                                     Department, Bubbling
                                     Ponds Hatchery and
                                     Page Springs
                                     Hatchery (State
                                     Wildlife Action
                                     Plan).
----------------------------------------------------------------------------------------------------------------

[[Page 23643]]

 
Unit total being considered for     .....................  .....................       460 (186)              9%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                        Bill Williams River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Bill Williams River...............  Arizona Game and Fish  State................       329 (133)             18%
                                     Department, Planet
                                     Ranch Conservation
                                     and Wildlife Area
                                     (State Wildlife
                                     Action Plan).
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................       329 (133)              8%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                           Cienega Creek Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Cienega Creek.....................  Pima County, Cienega   Private..............       543 (220)             34%
                                     Creek Natural
                                     Preserve (Pima
                                     County MSCP).
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................       543 (220)             27%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                      Upper Santa Cruz River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Sonoita Creek.....................  The Nature             Private..............        123 (50)             55%
                                     Conservancy,
                                     Patagonia-Sonoita
                                     Creek Preserve.
Santa Cruz River..................  San Rafael Cattle      Private..............         91 (37)             57%
                                     Company, San Rafael
                                     Ranch (San Rafael
                                     Ranch Low-effect
                                     HCP).
Unnamed Drainage and Pasture 9      San Rafael Cattle      Private..............           5 (2)             12%
 Tank.                               Company, San Rafael
                                     Ranch (AGFD's SHA,
                                     San Rafael Ranch Low
                                     Effect HCP).
Unnamed Drainage and Sheehy Spring  San Rafael Cattle      Private..............          20 (8)             80%
                                     Company, San Rafael
                                     Ranch (AGFD's SHA,
                                     San Rafael Ranch Low
                                     Effect HCP).
Unnamed Wildlife Pond.............  Private Ranch (AGFD's  Private..............     0.07 (0.03)            100%
                                     SHA).
Unit total being considered for     .....................  .....................        238 (96)             48%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                       Upper San Pedro River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
San Pedro River (Fort Huachuca      Bureau of Land         Federal..............   4,496 (1,820)             88%
 requested exclusion).               Management, San
                                     Pedro Riparian
                                     National
                                     Conservation Area
                                     (national security).
                                    Private (national      Private..............        215 (87)              4%
                                     security).
Babocomari River (Fort Huachuca     Bureau of Land         Federal..............        195 (79)             49%
 requested exclusion).               Management, San
                                     Pedro Riparian
                                     National
                                     Conservation Area
                                     (national security).
                                    Arizona State Land     State................           8 (3)              2%
                                     Department (national
                                     security).
                                    Private (national      Private..............        199 (81)             49%
                                     security).
O'Donnell Canyon..................  National Audubon       Private..............        173 (70)             72%
                                     Society, Appleton-
                                     Whittell Research
                                     Ranch (AGFD's SHA).
                                    The Nature             Private..............       1.8 (0.7)             0.8
                                     Conservancy, Canelo
                                     Hills Preserve.
Post Canyon.......................  National Audubon       Private..............          15 (6)             19%
                                     Society, Appleton-
                                     Whittell Research
                                     Ranch (AGFD's SHA).
                                    Private Ranch (AGFD's  Private..............          15 (6)             19%
                                     SHA).
Unnamed Drainage and Finley Tank..  National Audubon       Private..............           3 (1)            100%
                                     Society, Appleton-
                                     Whittell Research
                                     Ranch (AGFD's SHA).
Unit total being considered for     .....................  .....................   5,320 (2,152)             91%
 exclusion.
                                                                                 -------------------------------
    Grand Total...................  .....................  .....................   7,405 (2,997)             27%
----------------------------------------------------------------------------------------------------------------


[[Page 23644]]


 Table 3b--Areas Considered for Exclusion for the Narrow-Headed Gartersnake by Critical Habitat Unit and Subunit
----------------------------------------------------------------------------------------------------------------
                                                                                                    Portion of
           Unit subunit              Landowner, property       Ownership type      Area in acres      unit or
                                             name                                   (hectares)        subunit
----------------------------------------------------------------------------------------------------------------
                                         Upper Gila River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Gila River........................  Freeport McMoRan       Private..............       563 (228)             10%
                                     (Freeport McMoRan
                                     Corporation
                                     management plans).
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................       563 (228)             10%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                                Eagle Creek Unit
----------------------------------------------------------------------------------------------------------------
Eagle Creek.......................  San Carlos Apache      Tribal...............        236 (96)             70%
                                     Tribe.
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................        236 (96)             70%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                            Black River Subbasin Unit
----------------------------------------------------------------------------------------------------------------
Black River.......................  *San Carlos Apache     Tribal...............         55 (22)              7%
                                     Tribe.
----------------------------------------------------------------------------------------------------------------
                                    White Mountain Apache  Tribal...............         56 (23)              7%
                                     Tribe.
Bear Wallow Creek.................  San Carlos Apache      Tribal...............         48 (19)             27%
                                     Tribe.
                                    White Mountain Apache  Tribal...............     <.01 (<.01)           <.01%
                                     Tribe.
Reservation Creek.................  White Mountain Apache  Tribal...............         36 (15)             27%
                                     Tribe.
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................        195 (79)             12%
 exclusion.
----------------------------------------------------------------------------------------------------------------
                                                Canyon Creek Unit
----------------------------------------------------------------------------------------------------------------
Canyon Creek......................  White Mountain Apache  Tribal...............         77 (31)             33%
                                     Tribe.
----------------------------------------------------------------------------------------------------------------
Unit total being considered for     .....................  .....................         77 (31)             33%
 exclusion.
                                                                                 -------------------------------
    Grand Total...................  .....................  .....................     1,072 (434)              6%
----------------------------------------------------------------------------------------------------------------

    We specifically request comments on the inclusion or exclusion of 
such areas in our final designation of critical habitat for the 
northern Mexican gartersnake and narrow-headed gartersnake (see Public 
Comments under Request for Information, above).

Required Determinations

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 ADDRESSES. 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.

Regulatory Planning and Review (Executive Orders 12866 and 13563)

    Executive Order 12866 provides that the Office of Information and 
Regulatory Affairs (OIRA) in the Office of Management and Budget will 
review all significant rules. OIRA has determined that this rule is not 
significant.
    Executive Order (E.O.) 13563 reaffirms the principles of E.O. 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 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. E.O. 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 proposed 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 of 
1996 (SBREFA; 5 U.S.C. 801 et seq.), whenever an agency is required to 
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 
(i.e., 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

[[Page 23645]]

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 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 agricultural businesses with 
annual sales less than $750,000. To determine if potential economic 
impacts to these small entities are significant, we considered 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.
    Under the RFA, as amended, and as understood in the light of recent 
court decisions, Federal agencies are required to evaluate the 
potential incremental impacts of rulemaking only on those entities 
directly regulated by the rulemaking itself and, therefore, are not 
required to evaluate the potential impacts to indirectly regulated 
entities. The regulatory mechanism through which critical habitat 
protections are realized is section 7 of the Act, which requires 
Federal agencies, in consultation with the Service, to ensure that any 
action authorized, funded, or carried out by the agency is not likely 
to destroy or adversely modify critical habitat. Therefore, under 
section 7, only Federal action agencies are directly subject to the 
specific regulatory requirement (avoiding destruction and adverse 
modification) imposed by critical habitat designation. Consequently, it 
is our position that only Federal action agencies would be directly 
regulated if we adopt this revised proposed critical habitat 
designation. There is no requirement under the RFA to evaluate the 
potential impacts to entities not directly regulated. Moreover, Federal 
agencies are not small entities. Therefore, because no small entities 
would be directly regulated by this rulemaking, the Service certifies 
that, if made final as proposed, the revised proposed critical habitat 
designation will not have a significant economic impact on a 
substantial number of small entities.
    In summary, we have considered whether this revised proposed 
designation would result in a significant economic impact on a 
substantial number of small entities. For the above reasons and based 
on currently available information, we certify that, if made final, the 
revised proposed critical habitat designation will not have a 
significant economic impact on a substantial number of small business 
entities. Therefore, an initial regulatory flexibility analysis is not 
required.

Executive Order 13771--Reducing Regulation and Controlling Regulatory 
Costs

    This proposed rule is not an Executive Order (E.O.) 13771 
(``Reducing Regulation and Controlling Regulatory Costs'') (82 FR 9339, 
February 3, 2017) regulatory action because this rule is not 
significant under E.O. 12866.

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. In our economic analysis, we did not find that the 
proposed critical habitat designation would significantly affect energy 
supplies, distribution, or use. Therefore, this action is not a 
significant energy action, and no Statement of Energy Effects is 
required.

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 finding:
    (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 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 do not think that this rule would significantly or uniquely 
affect small governments. The lands being proposed for critical habitat 
designation are owned by Pima County, private landowners, Tribes, the 
States of New Mexico and Arizona, and the Federal Government (U.S. 
Forest Service, National Park Service, Bureau of Land Management, and 
U.S. Fish and

[[Page 23646]]

Wildlife Service). In addition, based in part on an analysis conducted 
for the previous proposed designation of critical habitat and 
extrapolated to this designation, we do not expect this rule to 
significantly or uniquely affect small governments. Small governments 
will be affected only to the extent that any programs or actions 
requiring or using Federal funds, permits, or other authorized 
activities must ensure that their actions will not adversely affect the 
critical habitat. Further, we do not believe that this rule would 
significantly or uniquely affect small governments because it will not 
produce a Federal mandate of $100 million or greater in any year, that 
is, it is not a ``significant regulatory action'' under the Unfunded 
Mandates Reform Act. The designation of critical habitat imposes no 
obligations on State or local governments and, as such, a Small 
Government Agency Plan is not required. Therefore, a Small Government 
Agency Plan is not required.

Takings--Executive Order 12630

    In accordance with E.O. 12630 (Government Actions and Interference 
with Constitutionally Protected Private Property Rights), we have 
analyzed the potential takings implications of designating critical 
habitat for northern Mexican gartersnake and narrow-headed gartersnake 
in a takings implications assessment. The Act does not authorize the 
Service to regulate private actions on private lands or confiscate 
private property as a result of critical habitat designation. 
Designation of critical habitat does not affect land ownership, or 
establish any closures, or restrictions on use of or access to the 
designated areas. Furthermore, the designation of critical habitat 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. However, Federal 
agencies are prohibited from carrying out, funding, or authorizing 
actions that would destroy or adversely modify critical habitat. A 
takings implications assessment has been completed for the proposed 
designation of critical habitat for northern Mexican gartersnake and 
narrow-headed gartersnake, and it concludes that, if adopted, this 
designation of critical habitat does not pose significant takings 
implications for lands within or affected by the designation.

Federalism--Executive Order 13132

    In accordance with E.O. 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. From a federalism 
perspective, the designation of critical habitat directly affects only 
the responsibilities of Federal agencies. The Act imposes no other 
duties with respect to critical habitat, either for States and local 
governments, or for anyone else. As a result, the proposed rule does 
not have substantial direct effects either on the States, or on the 
relationship between the national government and the States, or on the 
distribution of powers and responsibilities among the various levels of 
government. The proposed designation may have some benefit to these 
governments because the areas that contain the features essential to 
the conservation of the species are more clearly defined, and the 
physical or biological features of the habitat necessary for 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 State and local 
governments in long-range planning because they no longer have to 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) of the Act 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 would not 
unduly burden the judicial system and that it meets the requirements of 
sections 3(a) and 3(b)(2) of the Order. We have proposed designating 
critical habitat in accordance with the provisions of the Act. To 
assist the public in understanding the habitat needs of the species, 
this proposed rule identifies the elements of physical or biological 
features essential to the conservation of the species. The proposed 
designated areas of critical habitat are presented on maps, and the 
proposed 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 information collection requirements, and 
a submission to the Office of Management and Budget (OMB) under the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.) is not 
required. We may not conduct or sponsor and you are not required to 
respond to a collection of information unless it displays a currently 
valid OMB control number.

National Environmental Policy Act (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 the National Environmental Policy 
Act (NEPA; 42 U.S.C. 4321 et seq.) in connection with designating 
critical habitat under the 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 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 undertake 
a NEPA analysis for critical habitat designation. We invite the public 
to comment on the extent to which this proposed critical habitat 
designation may have a significant impact on the human environment, or 
fall within one of the categorical exclusions for actions that have no 
individual or cumulative effect on the quality of the human 
environment.

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

[[Page 23647]]

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 federally recognized 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 described above under Criteria Used To Identify Critical 
Habitat 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 pre-
decisional information. During an April 2, 2019, coordination meeting 
with these tribes, we informed them that we were revising the proposed 
critical habitat designation for the two gartersnakes and would have 
meetings with them as early as legally possible regarding the 
revisions. We plan to meet with these tribes and any other interested 
tribes in early April 2020 so that we can provide ample time to 
comment. We will continue to work with tribal entities during the 
development of a final rule for the designation of critical habitat for 
the northern Mexican and narrow-headed gartersnakes

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 proposed rulemaking 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--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

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. Amend Sec.  17.11(h) by revising the entries for ``Gartersnake, 
narrow-headed'' and ``Gartersnake, northern Mexican'' under REPTILES in 
the List of Endangered and Threatened Wildlife to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                              Listing citations
           Common name                Scientific name        Where listed         Status        and applicable
                                                                                                    rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
             Reptiles
 
                                                  * * * * * * *
Gartersnake, narrow-headed.......  Thamnophis            Wherever found......            T   79 FR 38677, 7/8/
                                    rufipunctatus.                                            2014; 50 CFR
                                                                                              17.95(c).\CH\
Gartersnake, northern Mexican....  Thamnophis eques      Wherever found......            T   79 FR 38677, 7/8/
                                    megalops.                                                 2014; 50 CFR
                                                                                              17.42(g);\4d\ 50
                                                                                              CFR 17.95(c).\CH\
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

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


Sec.  17.95   Critical habitat--fish and wildlife.

* * * * *
    (c) Reptiles.
* * * * *
Narrow-Headed Gartersnake (Thamnophis rufipunctatus)
    (1) Critical habitat units are depicted for Apache, Coconino, Gila, 
Graham, Greelee, and Yavapai Counties in Arizona, and Catron, Grant, 
and Hidalgo Counties in New Mexico, on the maps in this entry.
    (2) Within these areas, the physical or biological features 
essential to the conservation of narrow-headed gartersnake consist of 
the following components:
    (i) Perennial streams or spatially intermittent streams that 
provide both aquatic and terrestrial habitat that allows for 
immigration, emigration, and maintenance of population connectivity of 
narrow-headed gartersnakes and contain:
    (A) Pools, riffles, and cobble and boulder substrate, with low 
amount of fine sediment and substrate embeddedness;
    (B) Organic and natural inorganic structural features (e.g., cobble 
bars, rock piles, large boulders, logs or

[[Page 23648]]

stumps, aquatic and wetland vegetation, logs, and debris jams) in the 
stream channel for basking, thermoregulation, shelter, prey base 
maintenance, and protection from predators;
    (C) Water quality that is absent of pollutants or, if pollutants 
are present, at levels low enough such that recruitment of narrow-
headed gartersnakes is not inhibited; and
    (D) Terrestrial habitat within 89 feet (27 meters) of the active 
stream channel that includes boulder fields, rocks, and rock structures 
containing cracks and crevices, small mammal burrows, downed woody 
debris, and vegetation for thermoregulation, shelter sites, and 
protection from predators.
    (ii) Hydrologic processes that maintain aquatic and riparian 
habitat through:
    (A) A natural flow regime that allows for periodic flooding, or if 
flows are modified or regulated, a flow regime that allows for the 
movement of water, sediment, nutrients, and debris through the stream 
network, as well as maintenance of native fish populations; and
    (B) Physical hydrologic and geomorphic connection between the 
active stream channel and its adjacent terrestrial areas.
    (iii) Prey base of native fishes, or soft-rayed, nonnative fish 
species.
    (iv) An absence of nonnative predators, such as fish species of the 
families Centrarchidae and Ictaluridae, bullfrogs, and crayfish, or 
occurrence of nonnative predators at low enough densities such that 
recruitment of narrow-headed gartersnakes is not inhibited and 
maintenance of viable prey populations is still occurring.
    (v) Elevations of 2,300 to 8,200 feet (700 to 2,500 meters).
    (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 
included the U.S. Geological Survey's 7.5' quadrangles, National 
Hydrography Dataset and National Elevation Dataset; the Service's 
National Wetlands Inventory dataset; and aerial imagery from Google 
Earth Pro. Line locations for lotic streams (flowing water) and 
drainages are depicted as the ``Flowline'' feature class from the 
National Hydrography Dataset geodatabase. The active channel along a 
stream is depicted as the ``Wetlands'' feature class from the Service's 
National Wetlands Inventory dataset. Any discrepancies between the 
``Flowline'' and ``Wetlands'' feature classes were resolved using 
aerial imagery from Google Earth Pro. Elevation range is masked using 
the ``Elev_Contour'' feature class of the National Elevation Dataset. 
The 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). The maps in this entry, as modified by any 
accompanying regulatory text, establish the boundaries of the critical 
habitat designation. The coordinates or plot points or both on which 
each map is based are available to the public at the Service's internet 
site at http://www.fws.gov/southwest/es/arizona/, at http://www.regulations.gov at Docket No. FWS-R2-ES-2020-0011, and at the field 
office responsible for this designation. You may obtain field office 
location information by contacting one of the Service regional offices, 
the addresses of which are listed at 50 CFR 2.2.
    (5) Note: Index map follows:
BILLING CODE P

[[Page 23649]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.000

    (6) Unit 1: Upper Gila River Subbasin Unit, Grant and Hidalgo 
Counties, New Mexico.
    (i) General description: Unit 1 consists of 5,429 ac (2,197 ha) in 
Grant and Hidalgo Counties, and is composed of lands in Federal (2,827 
ac (1,144 ha)), State (278 ac (113 ha)), and private (2,323 ac (940 
ha)) ownership in eight subunits west of the town of Glenwood, north of 
Silver City, and South of Gila and Cliff.
    (ii) Map of Unit 1 follows:

[[Page 23650]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.001

    (7) Unit 2: San Francisco River Subbasin Unit, Catron County, New 
Mexico.
    (i) General description: Unit 2 consists of 4,905 ac (1,985 ha) in 
Catron County, and is composed of lands in Federal (2,753 ac (1,114 
ha)) and private (2,152 ac (871 ha)) ownership in six subunits near the 
towns of Glenwood and Reserve.
    (ii) Map of Unit 2 follows:

[[Page 23651]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.002

    (8) Unit 3: Blue River Subbasin Unit, Greenlee County, Arizona, and 
Catron County, New Mexico.
    (i) General description: Unit 3 consists of 2,971 ac (1,202 ha) in 
Greenlee County, Arizona, and Catron County, New Mexico, and is 
composed of lands in Federal (2,510 ac (1,016 ha)) and private (460 ac 
(186 ha)) ownership in three subunits near the towns of Blue, Arizona, 
and Luna, New Mexico.
    (ii) Map of Unit 3 follows:

[[Page 23652]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.003

    (9) Unit 4: Eagle Creek Unit, Graham and Greenlee Counties, 
Arizona.
    (i) General description: Unit 4 consists of 336 ac (136 ha) in 
Graham and Greenlee Counties, and is composed of lands in Federal (99 
ac (40 ha)), Tribal (236 ac (96 ha)), and private (1 ac (<1 ha)) 
ownership near the town of Morenci.
    (ii) Map of Unit 4 follows:

[[Page 23653]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.004

    (10) Unit 5: Black River Subbasin Unit, Apache, Graham, and 
Greenlee Counties, Arizona.
    (i) General description: Unit 5 consists of 1,607 ac (650 ha) in 
Apache, Graham, and Greenlee Counties, and is composed of lands in 
Federal (1,414 ac (572 ha)) and Tribal (194 ac (78 ha)) ownership in 
six subunits near the towns of Maverick and Hannigan Meadow.
    (ii) Map of Unit 5 follows:

[[Page 23654]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.005

    (11) Unit 6: Canyon Creek Unit, Gila County, Arizona.
    (i) General description: Unit 6 consists of 232 ac (94 ha) in Gila 
County, and is composed of lands in Federal (155 ac (63 ha)) and Tribal 
(77 ac (31 ha)) ownership southwest of the town of Heber.
    (ii) Map of Unit 6 follows:

[[Page 23655]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.006

    (12) Unit 7: Tonto Creek Subbasin Unit, Gila County, Arizona.
    (i) General description: Unit 7 consists of 1,390 ac (562 ha) in 
Gila County, and is composed of lands in Federal (1,285 ac (520 ha)) 
and private (105 ac (42 ha)) ownership in three subunits near the towns 
of Jakes Corner and Gisela.
    (ii) Map of Unit 7 follows:

[[Page 23656]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.007

    (13) Unit 8: Verde River Subbasin Unit, Coconino and Yavapai 
Counties, Arizona.
    (i) General description: Unit 8 consists of 1,832 ac (741 ha) in 
Coconino and Yavapai Counties, and is composed of lands in Federal 
(1,343 ac (544 ha)), State (51 ac (21 ha)), and private (437 ac (177 
ha)) ownership in three subunits near the towns of Sedona and 
Perkinsville.
    (ii) Map of Unit 8 follows:

[[Page 23657]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.008

BILLING CODE C
Northern Mexican Gartersnake (Thamnophis eques megalops)
    (1) Critical habitat units are depicted for La Paz, Mohave, 
Yavapai, Gila, Cochise, Santa Cruz, and Pima Counties in Arizona, and 
Grant County in New Mexico, on the maps in this entry.
    (2) Within these areas, the physical or biological features 
essential to the conservation of northern Mexican gartersnake consist 
of the following components:
    (i) Perennial or spatially intermittent streams that provide both 
aquatic and terrestrial habitat that allows for immigration, 
emigration, and maintenance of population connectivity of northern 
Mexican gartersnakes and contain:
    (A) Slow-moving water (walking speed) with in-stream pools, off-
channel pools, and backwater habitat;
    (B) Organic and natural inorganic structural features (e.g., 
boulders, dense aquatic and wetland vegetation, leaf litter, logs, and 
debris jams) within the stream channel for thermoregulation, shelter, 
foraging opportunities, and protection from predators;
    (C) Terrestrial habitat adjacent to the stream channel that 
includes riparian vegetation, small mammal burrows, boulder fields, 
rock crevices, and downed woody debris for thermoregulation, shelter, 
foraging opportunities, brumation, and protection from predators; and
    (D) Water quality that is absent of pollutants or, if pollutants 
are present, at levels low enough such that recruitment of northern 
Mexican gartersnakes is not inhibited.

[[Page 23658]]

    (ii) Hydrologic processes that maintain aquatic and terrestrial 
habitat through:
    (A) A natural flow regime that allows for periodic flooding, or if 
flows are modified or regulated, a flow regime that allows for the 
movement of water, sediment, nutrients, and debris through the stream 
network; and
    (B) Physical hydrologic and geomorphic connection between a stream 
channel and its adjacent riparian areas.
    (iii) Prey base of primarily native anurans, fishes, small mammals, 
lizards, and invertebrate 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 northern Mexican gartersnakes is not inhibited and 
maintenance of viable prey populations is still occurring.
    (v) Elevations from 130 to 8,500 feet (40 to 2,590 meters).
    (vi) Lentic wetlands including off-channel springs, cienegas, and 
natural and constructed ponds (small earthen impoundment) with:
    (A) Organic and natural inorganic structural features (e.g., 
boulders, dense aquatic and wetland vegetation, leaf litter, logs, and 
debris jams) within the ordinary high water mark for thermoregulation, 
shelter, foraging opportunities, brumation, and protection from 
predators;
    (B) Riparian habitat adjacent to ordinary high water mark that 
includes riparian vegetation, small mammal burrows, boulder fields, 
rock crevices, and downed woody debris for thermoregulation, shelter, 
foraging opportunities, and protection from predators; and
    (C) Water quality that is absent of pollutants or, if pollutants 
are present, at levels low enough such that recruitment of northern 
Mexican gartersnakes is not inhibited.
    (vii) Ephemeral channels that connect perennial or spatially 
interrupted perennial streams to lentic wetlands in southern Arizona 
where water resources are limited.
    (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 
included the U.S. Geological Survey's 7.5' quadrangles, National 
Hydrography Dataset, and National Elevation Dataset; the Service's 
National Wetlands Inventory dataset; and aerial imagery from Google 
Earth Pro. Line locations for lotic streams (flowing water) and 
drainages are depicted as the ``Flowline'' feature class from the 
National Hydrography Dataset geodatabase. Point locations for lentic 
sites (ponds) are depicted as ``NHDPoint'' feature class from the 
National Hydrography Dataset geodatabase. Extent of riparian habitat 
surrounding lotic streams and lentic sites is depicted by the greater 
of the ``Wetlands'' and ``Riparian'' features classes of the Service's 
national Wetlands Inventory dataset and further refined using aerial 
imagery from Google Earth Pro. Elevation range is masked using the 
``Elev_Contour'' feature class of the National Elevation Dataset. 
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). The maps in this entry, as modified by any 
accompanying regulatory text, establish the boundaries of the critical 
habitat designation. The coordinates or plot points or both on which 
each map is based are available to the public at the Service's internet 
site at http://www.fws.gov/southwest/es/arizona/, at http://www.regulations.gov at Docket No. FWS-R2-ES-2020-0011, and at the field 
office responsible for this designation. You may obtain field office 
location information by contacting one of the Service regional offices, 
the addresses of which are listed at 50 CFR 2.2.
    (5) Note: Index map follows:
BILLING CODE P

[[Page 23659]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.009

    (6) Unit 1: Upper Gila River Subbasin Unit, Grant County, New 
Mexico.
    (i) General description: Unit 1 consists of 1,132 ac (458 ha) in 
Grant County, and is composed of lands in State (22 ac (9 ha)), and 
private (1,110 ac (449 ha)) ownership in two subunits near the towns of 
Cliff and Gila.
    (ii) Map of Unit 1 follows:

[[Page 23660]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.010

    (7) Unit 2: Tonto Creek Unit, Gila County, Arizona.
    (i) General description: Unit 2 consists of 4,302 ac (1,741 ha) in 
Gila County, and is composed of lands in Federal (3,337 ac (1,350 ha)), 
and private (966 ac (391 ha)) ownership near the towns of Gisela and 
Punkin Center.
    (ii) Map of Unit 2 follows:

[[Page 23661]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.011

    (8) Unit 3: Verde River Subbasin Unit, Yavapai County, Arizona.
    (i) General description: Unit 3 consists of 5,246 ac (2,123 ha) in 
Yavapai County, and is composed of lands in Federal (856 ac (346 ha)), 
State (705 ac (285 ha)), Tribal (88 ac (36 ha), and private (3,597 ac 
(1,456 ha)) ownership in three subunits near the towns of Cottonwood, 
Cornville, Page Springs, and Camp Verde.
    (ii) Map of Unit 3 follows:

[[Page 23662]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.012

    (9) Unit 4: Bill Williams River Subbasin Unit, La Paz and Mohave 
Counties, Arizona.
    (i) General description: Unit 4 consists of 4,049 ac (1,639 ha) in 
La Paz and Mohave Counties, and is composed of lands in Federal (2,121 
ac (858 ha)), State (202 ac (82 ha)), and private (1,727 ac (699 ha)) 
ownership in three subunits near the towns of Parker and Signal.
    (ii) Map of Unit 4 follows:

[[Page 23663]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.013

    (10) Unit 5: Lower Colorado River Unit, Mojave County, Arizona.
    (i) General description: Unit 5 consists of 4,467 ac (1,808 ha) in 
Mojave County and is composed of lands in Federal ownership within the 
Havasu National Wildlife Refuge.
    (ii) Map of Unit 5 follows:

[[Page 23664]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.014

    (11) Unit 6: Arivaca Cienega Unit, Pima County, Arizona.
    (i) General description: Unit 6 consists of 211 ac (86 ha) in Pima 
County and is composed of lands in Federal (149 ac (60 ha)), State (1 
ac (<1 ha)), and private (62 ac (25 ha)) ownership near the town of 
Arivaca.
    (ii) Map of Unit 6 follows:

[[Page 23665]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.015

    (12) Unit 7: Cienega Creek Subbasin Unit, Pima County, Arizona.
    (i) General description: Unit 7 consists of 2,030 ac (821 ha) in 
Pima County and is composed of lands in Federal (1,112 ac (451 ha)), 
State (366 ac (148 ha)), and private (550 ac (220 ha)) ownership in 
four subunits near the towns of Tucson, Vail, and Sonoita.
    (ii) Map of Unit 7 follows:

[[Page 23666]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.016

    (13) Unit 8: Upper Santa Cruz River Subbasin Unit, Santa Cruz and 
Cochise Counties, Arizona.
    (i) General description: Unit 8 consists of 496 ac (201 ha) in 
Santa Cruz and Cochise Counties, and is composed of lands in Federal 
(45 ac (18 ha)), State (111 ac (45 ha)), and private (340 ac (138 ha)) 
ownership in eight subunits near the towns of Sonoita and Patagonia.
    (ii) Map of Unit 8 follows:

[[Page 23667]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.017

    (14) Unit 9: Upper San Pedro River Subbasin Unit, Cochise and Santa 
Cruz Counties, Arizona.
    (i) General description: Unit 9 consists of 5,850 ac (2,367 ha) in 
Cochise and Santa Cruz Counties, and is composed of lands in Federal 
(5,197 ac (2,103 ha)), State (8 ac (3 ha)), and private (645 ac (261 
ha)) ownership in six subunits near the towns of Sierra Vista and 
Elgin.
    (ii) Map of Unit 9 follows:

[[Page 23668]]

[GRAPHIC] [TIFF OMITTED] TP28AP20.018

BILLING CODE C
* * * * *

Aurelia Skipwith,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2020-08069 Filed 4-27-20; 8:45 am]
 BILLING CODE 4333-15-P