`[Federal Register Volume 89, Number 244 (Thursday, December 19, 2024)]
[Proposed Rules]
[Pages 103938-103989]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-29125]



[[Page 103937]]

Vol. 89

Thursday,

No. 244

December 19, 2024

Part II





 Department of the Interior





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 Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for Puerto Rican Skink, Lesser Virgin Islands Skink, and Virgin 
Islands Bronze Skink and Designation of Critical Habitat; Threatened 
Species Status With Section 4(d) Rule for Culebra Skink and Designation 
of Critical Habitat; Not Warranted Species Status for Mona Skink, 
Greater Virgin Islands Skink, Greater Saint Croix Skink, and Lesser 
Saint Croix Skink; Proposed Rule

  Federal Register / Vol. 89 , No. 244 / Thursday, December 19, 2024 / 
Proposed Rules  

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2024-0154; FXES1111090FEDR-256-FF09E21000]
RIN 1018-BH81


Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for Puerto Rican Skink, Lesser Virgin Islands Skink, and Virgin 
Islands Bronze Skink and Designation of Critical Habitat; Threatened 
Species Status With Section 4(d) Rule for Culebra Skink and Designation 
of Critical Habitat; Not Warranted Species Status for Mona Skink, 
Greater Virgin Islands Skink, Greater Saint Croix Skink, and Lesser 
Saint Croix Skink

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule and notification of findings.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
list the Puerto Rican skink (Spondylurus nitidus), a skink species from 
Puerto Rico and Desecheo Island, and the Lesser Virgin Islands skink 
(S. semitaeniatus) and Virgin Islands bronze skink (S. sloanii), two 
skink species from the U.S. Virgin Islands and the British Virgin 
Islands, as endangered species. We propose to list the Culebra skink 
(S. culebrae), a skink species from Culebra Island and offshore cays of 
Puerto Rico, as a threatened species with protective regulations under 
section 4(d) of the Endangered Species Act of 1973, as amended (Act) 
(``4(d) rule''). After a review of the best available scientific and 
commercial information, we find that listing these species is 
warranted. If we finalize this rule as proposed, we will add these 
species to the List of Endangered and Threatened Wildlife and extend 
the Act's protections to these species. We also propose to designate 
critical habitat for the Puerto Rican skink, Culebra skink, Lesser 
Virgin Islands skink, and Virgin Islands bronze skink under the Act. We 
also announce the availability of an economic analysis of the proposed 
designation of critical habitat for the Puerto Rican skink, Culebra 
skink, Lesser Virgin Islands skink, and Virgin Islands bronze skink. We 
find that it is not warranted at this time to list the Mona skink 
(Spondylurus monae), the Greater Virgin Islands skink (S. spilonotus), 
the Greater Saint Croix skink (S. magnacruzae), and the Lesser Saint 
Croix skink (Capitellum parvicruzae). However, we ask the public to 
submit to us at any time any new information relevant to the status of 
any of the species mentioned above and their habitats.

DATES: We will accept comments received or postmarked on or before 
February 18, 2025. 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 a 
public hearing, in writing, at the address shown in FOR FURTHER 
INFORMATION CONTACT by February 3, 2025.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal:
    https://www.regulations.gov. In the Search box, enter FWS-R4-ES-
2024-0154, which is the docket number for this rulemaking. Then, click 
on the Search button. On the resulting page, in the 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.''
    (2) By hard copy: Submit by U.S. mail to: Public Comments 
Processing, Attn: FWS-R4-ES-2024-0154, U.S. Fish and Wildlife Service, 
MS: PRB/3W, 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 https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see Information Requested, below, for more information).
    Availability of supporting materials: Supporting materials, such as 
the species status assessment report, are available on the Service's 
website at https://www.fws.gov/office/caribbean-ecological-services, at 
https://www.regulations.gov at Docket No. FWS-R4-ES-2024-0154, or both.

FOR FURTHER INFORMATION CONTACT: Lourdes Mena, Field Supervisor, U.S. 
Fish and Wildlife Service, Caribbean Ecological Services Field Office, 
P.O. Box 491, Boquer[oacute]n, PR 00622; telephone 352-749-2462; email: 
[email protected]. Individuals in the United States who are deaf, 
deafblind, hard of hearing, or have a speech disability may dial 711 
(TTY, TDD, or TeleBraille) to access telecommunications relay services. 
Individuals outside the United States should use the relay services 
offered within their country to make international calls to the point-
of-contact in the United States. Please see Docket No. FWS-R4-ES-2024-
0154 on https://www.regulations.gov for a document that summarizes this 
proposed rule.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Act, a species warrants 
listing if it meets the definition of an endangered species (in danger 
of extinction throughout all or a significant portion of its range) or 
a threatened species (likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range). If we determine that a species warrants listing, we must list 
the species promptly and designate the species' critical habitat to the 
maximum extent prudent and determinable. We have determined that the 
Puerto Rican skink, Lesser Virgin Islands skink, and Virgin Islands 
bronze skink meet the Act's definition of endangered species and the 
Culebra skink meets the definition of a threatened species; therefore, 
we are proposing to list them as such and propose designation of 
critical habitat for each species. Both listing a species as an 
endangered or threatened species and making a critical habitat 
designation can be completed only by issuing a rule through the 
Administrative Procedure Act rulemaking process (5 U.S.C. 551 et seq.).
    What this document does. We propose to add the Puerto Rican skink, 
Lesser Virgin Islands skink, and Virgin Islands bronze skink as 
endangered species to the List of Endangered and Threatened Wildlife 
(List) in title 50 of the Code of Federal Regulations at 50 CFR 17.11. 
We also propose adding the Culebra skink as a threatened species to the 
List with a rule under section 4(d) of the Act, and we propose the 
designation of critical habitat for all of these species. This document 
serves as our 12-month petition findings for the Puerto Rican skink, 
Lesser Virgin Islands skink, Virgin Islands bronze skink, and the 
Culebra skink. We also announce 12-month petition findings that the 
Mona skink, Greater Virgin Islands skink, Greater Saint Croix skink, 
and Lesser Saint Croix skink are not warranted for listing as 
endangered or threatened species under the Act.
    The basis for our action. Under the Act, we may determine that a 
species is an endangered or threatened species because of any of five 
factors: (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range; (B) overutilization for 
commercial, recreational, scientific, or

[[Page 103939]]

educational purposes; (C) disease or predation; (D) the inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence. We have determined that the Puerto 
Rican skink, Lesser Virgin Islands skink, and Virgin Islands bronze 
skink are endangered species due to the following threats: nonnative 
predators (Factor C) and habitat loss and degradation from development 
(Factor A). We have determined that the Culebra skink is a threatened 
species due to the following threats: nonnative predators (Factor C), 
habitat loss and degradation from development (Factor A), and sea level 
rise and storm surge from a changing climate (Factor E).
    Section 4(a)(3) of the Act requires the Secretary of the Interior 
(Secretary), to the maximum extent prudent and determinable, 
concurrently with listing designate critical habitat for the species. 
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. 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.

Information Requested

    We intend that any final actions resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other governmental agencies, Native 
American Tribes, the scientific community, industry, or any other 
interested parties concerning this proposed rule. We particularly seek 
comments concerning:
    (1) Each skink species' biology, ranges, and population trends, 
including:
    (a) Biological or ecological requirements of the species, including 
habitat requirements for feeding, breeding, and sheltering;
    (b) Genetics and taxonomy;
    (c) Historical and current ranges, including distribution patterns 
and the locations of any additional populations of these species;
    (d) Historical and current population levels, and current and 
projected trends; and
    (e) Past and ongoing conservation measures for these species and/or 
their habitats.
    (2) Threats and conservation actions affecting the species, 
including:
    (a) Factors that may be affecting the continued existence of the 
species, which may include habitat modification or destruction, 
overutilization, disease, predation, the inadequacy of existing 
regulatory mechanisms, or other natural or manmade factors.
    (b) Biological, commercial trade, or other relevant data concerning 
any threats (or lack thereof) to these species.
    (c) Existing regulations or conservation actions that may be 
addressing threats to these species.
    (3) Additional information concerning the historical and current 
status of these species.
    (4) Information to assist us with applying or issuing protective 
regulations under section 4(d) of the Act that may be necessary and 
advisable to provide for the conservation of the Culebra skink, in 
particular, whether we should consider any additional or different 
exceptions from the prohibitions in the 4(d) rule.
    (5) Specific information related to critical habitat, such as:
    (a) The amount and distribution of Puerto Rican skink, Culebra 
skink, Lesser Virgin Islands skink, and Virgin Islands bronze skink 
habitat;
    (b) Any additional areas occurring within the range of each of the 
species, including Puerto Rico and surrounding islands and cays as well 
as the U.S. Virgin Islands and British Virgin Islands, that should be 
included in the designation because they (i) are occupied at the time 
of listing and contain the physical or biological features that are 
essential to the conservation of the species and that may require 
special management considerations or protection, or (ii) are unoccupied 
at the time of listing and are essential for the conservation of the 
species;
    (c) Special management considerations or protection that may be 
needed in critical habitat areas we are proposing, including managing 
for the potential effects of predators and climate change; and
    (d) Whether areas not occupied at the time of listing qualify as 
habitat for the species and are essential for the conservation of the 
species.
    (6) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat.
    (7) Any probable economic, national security, or other relevant 
impacts of designating any area that may be included in the final 
designation, and the related benefits of including or excluding 
specific areas.
    (8) Information on the extent to which the description of probable 
economic impacts in the economic analyses is a reasonable estimate of 
the likely economic impacts and any additional information regarding 
probable economic impacts that we should consider.
    (9) 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. If you think we should exclude any 
additional areas, please provide information supporting a benefit of 
exclusion.
    (10) 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, do not provide substantial 
information necessary to support a determination. 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, and section 4(b)(2) 
of the Act directs that the Secretary shall designate critical habitat 
on the basis of the best scientific 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 https://www.regulations.gov, your 
entire submission--including any personal identifying information--will 
be posted

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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 https://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 https://www.regulations.gov.
    Our final determination may differ from this proposal because we 
will consider all comments that we receive during the comment period as 
well as any information that may become available after this proposal. 
Based on the new information that we receive (and, if relevant, any 
comments on that new information), we may conclude that the Puerto 
Rican skink, Lesser Virgin Islands skink, or Virgin Islands bronze 
skink are threatened instead of endangered species, or that the Culebra 
skink is an endangered species instead of a threatened species, or we 
may conclude that these species do not warrant listing as either 
endangered species or threatened species. For critical habitat, our 
final designation may not include all areas proposed, may include some 
additional areas that meet the definition of critical habitat, or may 
exclude some areas if we find the benefits of exclusion outweigh the 
benefits of inclusion and exclusion will not result in the extinction 
of the species. In addition, we may change the parameters of the 
prohibitions or the exceptions to those prohibitions in the protective 
regulations issued or applied under section 4(d) of the Act for Culebra 
skink if we conclude it is appropriate in light of comments and new 
information received. For example, we may expand the prohibitions if we 
conclude that the protective regulations as a whole, including those 
additional prohibitions, are necessary and advisable to provide for the 
conservation of the Culebra skink. Conversely, we may establish 
additional exceptions to the prohibitions in the final rule if we 
conclude that the activities would facilitate or are compatible with 
the conservation and recovery of the Culebra skink. In our final rule, 
we will clearly explain our rationale and the basis for our final 
decision, including why we made changes, if any, that differ from this 
proposal.

Public Hearing

    Section 4(b)(5) of the Act provides for a public hearing on this 
proposal, if requested. Requests must be received by the date specified 
in DATES. 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. We may hold the public hearing in person or virtually via 
webinar. We will announce any public hearing on our website, in 
addition to the Federal Register. The use of virtual public hearings is 
consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

    On February 11, 2014, we received a petition from the Center for 
Biological Diversity (CBD) and Dr. Renata Platenberg (reptile 
ecologist) requesting that nine Caribbean skink species be listed as 
endangered or threatened and that critical habitat be designated for 
these species under the Act. These nine species are: the Puerto Rican 
skink, the Culebra skink, the Mona skink, the Monito skink, the Greater 
and Lesser Virgin Islands skinks, the Virgin Islands bronze skink, and 
the Greater and Lesser Saint Croix skinks. We acknowledged receipt of 
this petition via email on February 12, 2014. On January 12, 2016, we 
published a positive 90-day finding (81 FR 1368) indicating that the 
petitioned action may be warranted and that the petition presented 
substantial scientific or commercial information for seven of the skink 
species. On March 16, 2016, we published a not-substantial 90-day 
finding (81 FR 14058) for Monito skink. On September 14, 2016, we 
published a substantial 90-day finding (81 FR 63160) for the Lesser 
Virgin Islands skink.
    On March 10, 2020, CBD issued a notice of intent to file suit to 
compel the Service to issue 12-month findings for the eight skinks with 
substantial 90-day findings. On September 22, 2020, CBD filed a 
complaint for declaratory and injunctive relief, stating that the 
Service had failed to make a timely determination for whether the eight 
species of Caribbean skink warrant protection under the Act. On May 27, 
2021, the Service agreed to a settlement to complete its review of the 
status of the skinks and submit 12-month findings to the Federal 
Register by December 12, 2024.

Peer Review

    A species status assessment (SSA) team prepared an SSA report for 
the Puerto Rican skink, Mona skink, Culebra skink, Greater Virgin 
Islands skink, Lesser Virgin Islands skink, Virgin Islands bronze 
skink, Greater Saint Croix skink, and Lesser Saint Croix skink (Service 
2023, entire). The SSA team was composed of Service biologists and a 
contractor from Texas A&M University, in consultation with other 
species experts. The SSA report represents a compilation of the best 
scientific and commercial data available concerning the status of each 
of the species, including the impacts of past, present, and future 
factors (both negative and beneficial) affecting each of the species.
    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 the role of peer review in 
listing actions under the Act (https://www.fws.gov/sites/default/files/documents/peer-review-policy-directors-memo-2016-08-22.pdf), we 
solicited independent scientific review of the information contained in 
the SSA report. We sent the SSA report to seven independent peer 
reviewers and received three responses. Results of this structured peer 
review process can be found at https://www.regulations.gov. In 
preparing this proposed rule, we incorporated the results of these 
reviews, as appropriate, into the SSA report, which is the foundation 
for this proposed rule.

Summary of Peer Reviewer Comments

    As discussed in Peer Review above, we received comments from three 
peer reviewers on the draft SSA report. We reviewed all comments we 
received from the peer reviewers for substantive issues and new 
information regarding the contents of the SSA report. The peer 
reviewers generally concurred with our methods and conclusions and 
provided clarifications and editorial suggestions. One reviewer 
indicated the Service was not justified in concluding that the Puerto 
Rican skink does not inhabit Culebra, Cayo Norte, and Cayo Luis Pena. 
The Service acknowledges it is possible that the Puerto Rican skink may 
have been in these locations historically; however, we lack genetic 
information that could confirm Puerto Rican skinks are sympatric with 
Culebra skinks. The SSA report provides this background in the 
historical distribution narrative (Service 2023, p. 33) but does not 
include Puerto Rican skinks in the distribution maps for these areas. 
We also received a comment disagreeing with information presented in 
appendix B of the SSA report (Service 2023, pp. 146-169) summarizing 
the likely extinct status of the Greater Virgin Islands skink, Greater 
Saint Croix skink, and

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Lesser Saint Croix skink, referencing the discrepancy with the 
International Union for Conservation's (IUCN) criterion for possible 
extinction. The Service does not use the IUCN criterion to determine 
whether a species is extinct. The Service used the best available 
information, as presented in the SSA report, to determine that these 
species are extinct. Otherwise, no substantive changes to our analysis 
and conclusions within the SSA report were deemed necessary, and peer 
review comments are addressed in version 1.0 of the SSA report.

I. Proposed Listing Determination

Background

    A thorough review of the taxonomy, genetics, life history, and 
ecology of each of the skink species is presented in the SSA report 
(Service 2023, pp. 17-43), and species-specific distribution 
information follows the general overview below.
    The eight Caribbean skink species--Puerto Rican skink, Mona skink, 
Culebra skink, Greater Virgin Islands skink, Lesser Virgin Islands 
skink, Virgin Islands bronze skink, Greater Saint Croix skink, and 
Lesser Saint Croix skink--have similar patterns and coloration. All are 
generally some shades of tans and browns, with a pair of dark lateral 
stripes and limb pattern, if present, with spots or blotches (Hedges 
and Conn 2012, pp. 14-15). Juveniles often have blue tails. Available 
information suggests that females are slightly larger than males 
(Hedges and Conn 2012, p. 10). Adult snout-vent length (SVL) will also 
differ slightly between species, but in general ranges from 
approximately 3 to 4 inches (in) (7.6 to 10 centimeters (cm)).
    Caribbean skinks are ectothermic (cold-blooded) animals and 
therefore highly dependent on the air and soil temperature to 
thermoregulate (maintain body core temperature) (Noble et al. 2017, p. 
72) and are often observed basking in the sun on rocks, leaf litter, 
and fallen logs in forest habitat (Henderson and Powell 2009, p. 293; 
Sanchez 2013, p. 1). Caribbean skinks have been observed on the ground, 
shrubs, cacti, trees, boulder and limestone rocks, leaf litter, on and 
under debris piles, under rocks and rock fissures, near human 
habitation and houses, and are known to hide from perceived predators 
under or within rocks, vegetation, and debris or when they are not 
basking (Bullock and Evans 1990, p. 428; Henderson and Powell 2009, pp. 
292-293, Hedges and Conn 2012, entire).
    Very little information exists about the diet and foraging behavior 
of Caribbean skinks. They appear to be diurnal and primarily hunt for 
prey by actively foraging in dry coastal woodlands but are known to be 
somewhat omnivorous including consumption of some plants (Platenberg 
and Boulon 2006, p. 224; Daudin and de Silva 2011, p. 265; Henderson 
and Powell 2009, pp. 292-293; Hedges and Conn 2012, p. 220). Some 
information specifies that the skink diet is omnivorous, including 
insects, fruits, and even a common coqui (Eleutherodactylus coqui) in 
Puerto Rico (Henderson and Powell 2009, p. 293).
    Caribbean skinks are viviparous (i.e., bearing live young). It is 
theorized that the timing of birth in viviparous skinks is meant to 
maximize food availability (Vrcibradic and Rocha 2011, p. 822; Hedges 
and Conn 2012, p. 223) as well as maximize optimal conditions for 
growth and survival of neonates (Abts 1988, p. 389; Olsson and Shine 
1997, entire). Most skink species reproduce annually, but many skinks 
have more than one brood; however, it is unknown which reproductive 
strategy is exhibited in female Caribbean skinks. Collection of 
specimens indicates Caribbean skinks are gravid during the dry season, 
which is January through April, and birthing occurs primarily in 
February through May (Hedges and Conn 2012, p. 223). Little information 
is available about the influences on fecundity of Caribbean skinks. 
Given that Spondylurus reproductive strategy is similar to other 
viviparous skinks, maternal thermoregulation (i.e., basking behavior) 
is likely used by female Caribbean skinks to keep developing embryos at 
optimal temperatures for development of the young. Therefore, 
influences on basking time of female skinks (e.g., the presence of 
predators) could have the potential to decrease the fecundity of 
Caribbean skinks or decrease the survival of young skinks.
    No population estimates are available for the eight skink species. 
During 2021-2022 skink surveys (Rivera et al. 2023, p. 9), there were 
42 observations of Puerto Rican skinks, 8 of Mona skinks, 59 of Culebra 
skinks, and 4 of Virgin Islands bronze skinks. In addition, on Desecheo 
Island, five Puerto Rican skinks were encountered during a 6-day 
herpetological survey (Herrera-Giraldo and Bermudez 2010, p. 22).
    Current and historical distributions of the eight Caribbean skink 
species encompass the islands of Puerto Rico, the U.S. Virgin Islands 
(USVI), and the British Virgin Islands (BVI). The Puerto Rican skink, 
the Mona skink, and the Culebra skink all fall within the U.S. 
territory of Puerto Rico, which includes the main island of Puerto Rico 
and surrounding islands (figure 1). The Puerto Rican skink's current 
range includes the main island of Puerto Rico and Desecheo (figure 1).
BILLING CODE 4333-15-P

[[Page 103942]]

[GRAPHIC] [TIFF OMITTED] TP19DE24.000

    The Mona skink occurs on only one island, Mona Island, off the west 
coast of Puerto Rico (figure 1). The current range of the Culebra skink 
encompasses the island of Culebra and its surrounding cays (Cayo Agua, 
Cayo Botella, Cayo Lobito, and Cayo Yerba), all occurring to the east 
of the main island of Puerto Rico (figure 1).

[[Page 103943]]

[GRAPHIC] [TIFF OMITTED] TP19DE24.001

    Species that did occur entirely within the USVI include the Greater 
Virgin Islands skink (figure 2), the Greater Saint Croix skink (figure 
3), and the Lesser Saint Croix skink (figure 3), all of which are 
considered likely extinct. The species that occur in both the USVI and 
BVI include the Lesser Virgin Islands skink and the Virgin Islands 
bronze skink (figure 2). The Lesser Virgin Islands skink has the 
largest range of all the Caribbean skink species and still occurs in 
both the USVI (Hans Lollik) and BVI (Guana Island, Mosquito Island, 
Tortola) (figure 2). The Virgin Islands bronze skink also had a larger 
range but is now confined to a few small to medium sized islands in the 
USVI (Buck Island, Water Island, Turtledove Cay; figure 2).

[[Page 103944]]

[GRAPHIC] [TIFF OMITTED] TP19DE24.002

BILLING CODE 4333-15-C

Regulatory and Analytical Framework

Regulatory Framework

    Section 4 of the Act (16 U.S.C. 1533) and the implementing 
regulations in title 50 of the Code of Federal Regulations set forth 
the procedures for determining whether a species is an endangered 
species or a threatened species, issuing protective regulations for 
threatened species, and designating critical habitat for endangered and 
threatened species.
    The Act defines an ``endangered species'' as a species that is in 
danger of extinction throughout all or a significant portion of its 
range and a ``threatened species'' as a species that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act requires that we 
determine whether any species is an endangered species or a threatened 
species because of any of the following factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the species' expected response and 
the effects of the threats--in light of those actions and conditions 
that will ameliorate the threats--on an individual, population, and 
species level. We evaluate each threat and its expected effects on the 
species, then analyze the cumulative effect of all of the threats on 
the species as a whole. We also consider the cumulative effect of the 
threats in light of those actions and conditions that will have 
positive effects on the species, such as any existing regulatory 
mechanisms or conservation efforts. The Secretary determines whether 
the species meets the definition of an ``endangered species'' or a 
``threatened species'' only after conducting this cumulative analysis 
and describing the expected effect on the species.
    The Act does not define the term ``foreseeable future,'' which 
appears in the statutory definition of ``threatened species.'' Our 
implementing regulations at 50 CFR 424.11(d) set forth a framework for 
evaluating the foreseeable future on a case-by-case basis, which is 
further described in the 2009 Memorandum Opinion on the foreseeable 
future from the Department

[[Page 103945]]

of the Interior, Office of the Solicitor (M-37021, January 16, 2009; 
``M-Opinion,'' available online at https://www.doi.gov/sites/doi.opengov.ibmcloud.com/files/uploads/M-37021.pdf). The foreseeable 
future extends as far into the future as the U.S. Fish and Wildlife 
Service and National Marine Fisheries Service (hereafter, the Services) 
can make reasonably reliable predictions about the threats to the 
species and the species' responses to those threats. We need not 
identify the foreseeable future in terms of a specific period of time. 
We will describe the foreseeable future on a case-by-case basis, using 
the best available data and taking into account considerations such as 
the species' life-history characteristics, threat projection 
timeframes, and environmental variability. In other words, the 
foreseeable future is the period of time over which we can make 
reasonably reliable predictions. ``Reliable'' does not mean 
``certain''; it means sufficient to provide a reasonable degree of 
confidence in the prediction, in light of the conservation purposes of 
the Act.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological review of the best scientific and commercial data regarding 
the status of the species, including an assessment of the potential 
threats to the species. The SSA report does not represent our decision 
on whether the species should be proposed for listing as an endangered 
or threatened species under the Act. However, it does provide the 
scientific basis that informs our regulatory decisions, which involve 
the further application of standards within the Act and its 
implementing regulations and policies.
    To assess Puerto Rican skink, Mona skink, Culebra skink, Greater 
Virgin Islands skink, Lesser Virgin Islands skink, Virgin Islands 
bronze skink, Greater Saint Croix skink, and Lesser Saint Croix skink 
viability, we used the three conservation biology principles of 
resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 
306-310). Briefly, resiliency is the ability of the species to 
withstand environmental and demographic stochasticity (for example, wet 
or dry, warm or cold years); redundancy is the ability of the species 
to withstand catastrophic events (for example, droughts, large 
pollution events); and representation is the ability of the species to 
adapt to both near-term and long-term changes in its physical and 
biological environment (for example, climate conditions, pathogens). In 
general, species viability will increase with increases in resiliency, 
redundancy, and representation (Smith et al. 2018, p. 306). Using these 
principles, we identified the species' ecological requirements for 
survival and reproduction at the individual, population, and species 
levels, and described the beneficial and risk factors influencing the 
species' viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated the individual species' life-
history needs. The next stage involved an assessment of the historical 
and current condition of the species' demographics and habitat 
characteristics, including an explanation of how the species arrived at 
its current condition. The final stage of the SSA involved making 
predictions about the species' responses to positive and negative 
environmental and anthropogenic influences. Throughout all of these 
stages, we used the best available information to characterize 
viability as the ability of a species to sustain populations in the 
wild over time, which we then used to inform our regulatory decision.
    The following is a summary of the key results and conclusions from 
the SSA report; the full SSA report can be found at Docket No. FWS-R4-
ES-2024-0154 on https://www.regulations.gov.

Summary of Biological Status and Threats

    In this discussion, we review the biological condition of each 
species and their resources, and the threats that influence the 
species' current and future conditions, in order to assess the species' 
overall viability and the risks to that viability.

Individual, Population, and Species Needs

    At the individual level, skinks require suitable foraging, basking, 
and shelter habitat to survive during each life stage from birth to 
adulthood, and to successfully reproduce. Individual needs of Caribbean 
skink species are: (1) trees, shrubs, bushes ground cover/leaf litter, 
cacti, debris, rocks, and crevices for shelter; (2) basking locations 
for thermoregulation; and (3) arthropods as a food source (Service 
2023, p. 44). Suitable habitat contains substrate that provides 
refugia, presence of vegetation, vertical spaces, and areas that offer 
both canopied and exposed sections for basking.
    Skink populations are defined as single island units except for 
mainland Puerto Rico (see Current Condition Methods, below). For 
populations to demonstrate resiliency, the needs of individual skinks 
must be met at a larger scale. Specific demographic information on 
population carrying capacity, birth rates, and reproductive success is 
lacking for these species. It can be inferred from individual needs 
that an interbreeding population requires the elements needed by 
individuals in sufficient quantities and configuration to support 
multiple individuals and life stages. Given the small size of skink 
species, patches that can support a population are expected to be 
relatively small (~3 ac (1.2 ha)), based on the size of the smallest 
occupied cays. In addition, while there are skink populations that have 
persisted alongside nonnative predators like cats or rats, in general, 
populations show higher resiliency where predators are few or absent. 
Further, nonnative predators are currently absent from small cays where 
skink populations have persisted (Service 2023, p. 45).
    For species' viability, there must be adequate redundancy (number 
of resilient populations with distribution and connectivity to allow 
the species to withstand catastrophic events) and representation 
(genetic and environmental diversity to allow the species to adapt to 
changing environmental conditions). The minimum number of resilient 
populations necessary to sustain each skink species is unknown, but we 
assume that populations with low resiliency contribute negligibly to 
overall species' viability. As island species, the relatively small, 
patchily distributed, and isolated cays can each support only small 
numbers of individuals (or separate populations). Redundancy improves 
with increasing numbers of populations distributed across the species' 
range, and connectivity allows connected populations to ``rescue'' each 
other after catastrophes. The level of redundancy (distribution) 
operating within a species is determined by the resiliency (abundance 
and health) of its populations. Representation, or adaptive capacity, 
improves with increased genetic and/or ecological diversity within and 
among populations. Long-term viability requires resilient populations 
in locations that are protected from the long-term catastrophic but 
permanent effects of climate change (e.g., sea level rise and effects 
from catastrophic hurricanes claiming low-lying habitat) and invasion 
of nonnative predators.

Influences

    Influences on the Caribbean skink species vary by location, but 
threats include nonnative predators, habitat

[[Page 103946]]

loss and degradation from development, and sea level rise and storm 
surge from a changing climate. Positive influences on the Caribbean 
skink species viability are habitat protection and predator control.
Nonnative Predators
    A primary threat to Caribbean skink populations is the presence of 
nonnative predators including cats (Felis catus), rats (Rattus sp.), 
and mongooses (Herpestes javanicus or Urva auropunctata).
    Mongooses are implicated in the decline and loss of several 
Caribbean skink species (Hedges and Conn 2012, pp. 224-229). Mongooses 
were introduced to the Caribbean during the late 19th and early 20th 
centuries with the goal of reducing rat populations. However, the 
presence of mongooses did not decrease rat densities, and mongooses 
have become a predator of many native vertebrate and invertebrate 
species in the Caribbean, including lizards (Wolcott 1953, entire; 
Witmer et al. 1998, p. 282; Henderson 1992, p. 3). Other reptile 
species with similar life history traits that are also endemic in the 
Caribbean have been shown to be vulnerable to mongoose depredation. For 
example, the endangered St. Croix ground lizard was extirpated from the 
main island of St. Croix in the 1900s, in part due to mongoose 
predation (Angeli and Fitzgerald 2021, p. 345). Lizards from the genus 
Ameiva (whiptail lizards) and snakes from the genera Alsophis (racers) 
are also susceptible to mongoose predation because they are diurnal, 
ground-dwelling, oviparous, active foragers, relatively small 
(Henderson 1992, p. 7), and easily caught by mongooses. Other than 
laying eggs (oviparity), these characteristics are shared by the 
Caribbean skink species.
    Feral cats have occurred for hundreds of years throughout the 
Caribbean near human development and are known to be predators of 
reptiles on numerous islands (Henderson 1992, p. 2; Service 2023, pp. 
46-47). Cats are instinctively natural predators and have been 
documented killing a variety of lizard species including five-lined 
skinks (Plestiodon fasciatus), broad-headed skinks (P. laticeps), and 
ground skinks (Scincella lateralis) (Mitchell and Beck 1992, p. 200). 
Cats are documented to have preyed on the Mona skink (L[oacute]pez-
Torres and Garc[iacute]a 2013, entire) and the Puerto Rican skink 
(Gonz[aacute]lez 2023, pers. comm.).
    Rats are known to depredate small lizards on many islands, 
including the St. Lucia whiptail lizard (Cnemidophorous vanzoi), the 
Belize leaf-tailed gecko (Phyllodactylus insularis) on Half Moon Cay, 
and blue-tailed skinks (Cryptoblepharus egeriae) on Christmas Island 
(Harper and Bunbury 2015, p. 616). However, the influence of rats on 
skink populations is unclear. Despite being omnivorous, rats' primary 
food on islands is arthropods and plants, suggesting that rats may be 
consuming the food sources of the skinks as well as depleting local 
vegetation. This consumption would lower the suitability of the habitat 
while also increasing depredation on the skinks themselves (Harper and 
Bunbury 2015, pp. 614, 616). Rats have a much more profound effect on 
skink populations that occur on very small islands and cays. 
Furthermore, rats are consistently introduced to islands, as they are 
easily transported by boats (Harper and Bunbury 2015, entire).
    Besides direct predation, skinks (as prey) may respond to the 
presence of predators by increasing their time seeking refuge at the 
cost of foraging, thermoregulation, and mating (Sih 1994, entire). 
Further, prey may be less adapted to changes in these pressures because 
these are introduced species (Mart[iacute]n and L[oacute]pez 1999, p. 
491). The impacts from nonnative predators are likely more severe on 
smaller islands because there is often a lower diversity of prey items 
for predators (Henderson 1992, p. 5).
Habitat Loss and Degradation
    Caribbean skinks occur on both private and publicly owned land. 
Where skinks occur in urban or rural areas, habitat loss and 
degradation resulting from development is a threat to populations. This 
is the case for Puerto Rico, Culebra, and the main developed islands in 
USVI and BVI. For example, in Puerto Rico, human activity has been 
described as ``intensive, pervasive, and fragments natural habitat'' 
(Lugo and Helmer 2004, p. 156). This is particularly true in the 
northern and eastern portions of the main island of Puerto Rico; 
however, the central and southern portions of the main island remain 
largely undeveloped (Gould et al. 2008, p. 91; see figure 4.3 in SSA 
report (Service 2023, p. 49)). Lands cleared for development would 
essentially eliminate potential habitat for the skinks and may directly 
kill individuals as well, particularly if development occurs in or 
adjacent to suitable skink habitat. And although forest areas have 
increased in Puerto Rico, unprotected forested areas are vulnerable to 
urban development, particularly those near or within urban centers 
(Kennaway and Helmer 2007, p. 376). In the USVI as well, human 
population growth has resulted in habitat loss and degradation of 
natural habitats, and most land is privately owned (Platenberg and 
Boulon 2006, p. 217).
    Skinks are now absent from completely developed urban landscapes 
that are not adjacent to natural habitat; however, skinks have been 
seen in and around rural residential areas in Puerto Rico within karst 
habitat and in residential and developed areas in Culebra (Zegarra 
2023, pers. comm.). This could be due to ``urban survival'' of the 
skinks, which is the idea that mongooses are less abundant in areas 
with larger human inhabitation because they are depredated by other 
nonnatives (e.g., dogs; Hedges and Conn 2012, p. 228). Skinks have also 
been observed using debris piles (i.e., vegetation and trash) 
accumulated on the side of roads and trails adjacent to forested 
habitat, and on human-made rock piles for road construction. As skink 
habitat is developed and encroached upon, observations of skinks in 
residential areas may become more common. However, skinks that occur 
within these areas are more susceptible to impacts from habitat loss as 
well as more susceptible to nonnative predators or competitors 
introduced by humans. While deforestation and fragmentation result from 
development, the extent of impacts to Caribbean skinks may range from 
low to high depending on each landscape as well as potential increased 
interactions with nonnative predators causing potential declines in 
skinks.
Climate Change: Sea Level Rise and Storm Surge
    One of the stressors affecting Caribbean skinks and their habitat 
is the shift in climate impacts occurring because of increasing 
greenhouse gas (GHG) emissions. The long-term persistence of several 
small cays in the Caribbean is being challenged by rising sea levels 
and the increased intensity of storm surges. The main stressors to the 
skinks and their habitat resulting from climate change are sea level 
rise (SLR) and increased storm surges.
    Relative sea levels have risen approximately 2 mm (0.08 in) per 
year in Puerto Rico and USVI since mid-20th century, and the rate or 
rise has been accelerating since the early 2000s (PRCCC 2022, p. 27). 
This recent acceleration suggests that, of the National Oceanic and 
Atmospheric Administration (NOAA) SLR scenarios based on different GHG 
emission scenarios (Sweet et al. 2017, pp. 21-22), the intermediate to 
high SLR scenarios are more likely to occur than the low and 
intermediate-low scenarios (Sweet et al. 2017, pp. 33-35; Sweet et al. 
2022,

[[Page 103947]]

p. 12). For Puerto Rico, the near-term range at 2050 is 1 foot (ft) 
(0.3 meter (m)) for the intermediate local SLR scenario and 1.6 ft (0.5 
m) for the high SLR scenario, and by 2100, the range is projected to be 
3.3 ft (1.0 m) for the intermediate SLR scenario and 6.6 ft (2.0 m) for 
the high SLR scenario (NOAA 2023, entire). Most of the impacts of SLR 
on Caribbean skinks will likely occur on low-lying cays in the region, 
beginning with increased saltwater flooding events from more frequent 
storms.
    Most measures of Atlantic hurricane activity have increased 
substantially since the early 1980s, the period during which high-
quality satellite data are available (Service 2023, p. 52). These 
include measures of intensity, frequency, and duration as well as the 
number of strongest (Category 4 and 5) storms (Walsh et.al. 2014, p. 
20). In the future, there is high confidence that SLR will increase 
storm inundation levels, and medium to high confidence that both 
precipitation rates and storm intensity will increase in hurricanes 
globally. In addition, there is medium to high confidence that the 
proportion of very strong storms (Category 4 and 5) will increase, but 
less confidence in increased frequency of storms overall (Knutson et 
al. 2020, p. E303). Strong rainstorms, tropical storms, and hurricanes 
are natural parts of a tropical ecosystem. However, with intensity, 
inundation levels, and precipitation all likely to increase, small 
patches and low-lying habitats are likely at risk. The resiliency of 
Caribbean skink species will likely be affected in these areas when the 
quantity and quality of their resources (food, cover) are compromised, 
particularly if there is not time to recover from previous events or 
areas are continually reduced over time.
    Saltwater surges and short-term flooding of upland habitats from 
strong storms and hurricanes on low-lying cays likely have and will 
continue to influence Caribbean skink persistence (D[iacute]az et al. 
2022, p. 66). The severity and duration of hurricane impacts to 
Caribbean skinks and their habitat vary based on the intensity and 
scale of these storm events. Localized impacts can vary greatly 
depending upon not only the strength of the storm, but the direction of 
its approach and how quickly it moves through the area. Storm surges 
and their intensity can also vary depending on location. In 2017, nine 
named storms impacted the Caribbean, including Hurricanes Irma and 
Maria (both Category 5). Irma caused catastrophic storm surges in the 
USVI although the peak water level is unknown because the tidal gauges 
in the area went offline during the storm. Storm tides from Maria 
measured between 6 ft to 9 ft (1.5 m to 2.7 m) above mean sea level in 
southwestern Puerto Rico (FEMA 2018, p. i).
    Impacts from heavy rainstorms, tropical storms, and hurricanes are 
part of this tropical islands system. The heavy inundation and even 
complete overwash of some islands during hurricanes may provide some 
explanation for the lack of skinks being observed, even when the island 
has recovered and again contains high-quality suitable skink habitat. 
Thus, storm events are likely a contributing factor to the low 
occurrence (historical and current) observed for several of the skink 
species. Individual skinks may colonize and occupy smaller islands only 
temporarily until storm events impact that island. Eventual 
recolonization of impacted islands by skinks is uncertain. Over time, 
storms could be a factor reducing the persistence of skink populations 
and thereby reducing the redundancy of the species.

Conservation Efforts and Regulatory Mechanisms

    We do not know of any skink-focused conservation actions or 
efforts. However, any past, current, and future eradication or control 
of nonnative species is beneficial for the skinks. For example, efforts 
to control mongoose populations on St. Thomas, St. John, and St. Croix 
have been attempted, and rats and mongooses were completely eradicated 
on Buck Island, St. Thomas, USVI (Barun et al. 2011, p. 20). Rats were 
also eradicated from Monito Island, eliminating that predation threat 
for the Monito skink and other species on that island (Garc[iacute]a 
et. al 2002, entire). Monkeys, goats, and rats were also eradicated 
from Desecheo Island, a National Wildlife Refuge (Will et al. 2019, 
entire). Eradication of pigs, cats, and possibly rats is being planned 
for Mona Island (Service 2023, entire). Permanent eradication of 
nonnatives is typically most effective on small islands that do not 
have human development.
    As skinks occur both on private and public lands, areas designated 
as nature reserves or refuges provide high-quality skink habitat as 
well as protection from development. For example, some of the most 
consistent skink observations for the Puerto Rican skink are from the 
Guajataca and Maricao Commonwealth Forests, two areas managed for 
conservation by the Puerto Rico Department of Natural and Environmental 
Resources (PRDNER). Skinks were also observed within the Montadero 
Natural Protected Area (Quebradillas Municipality, Puerto Rico) managed 
by the Puerto Rico Conservation Trust. Some of these karst forests are 
contained within the larger Karst Conservation Zone, a large area in 
Puerto Rico with stricter land regulations named the Karst Restricted 
Zone designated by the Puerto Rico Planning Board (Ortiz-Maldonado et 
al. 2019, entire). This Zone represents 7.2 percent (647 km\2\) of the 
total area of Puerto Rico, includes both public and private lands, and 
was designated as such for conservation purposes by prohibiting land 
exploitation of any type (Castro-Prieto et al. 2019, p. 59).
    The Mona skink has a wide distribution within the Mona Island 
Nature Reserve, managed for conservation by the PRDNER. The Puerto 
Rican skink has been reported from the Desecheo NWR, and the Culebra 
skink occurs within the Culebra NWR specifically within the Monte 
Resaca area and some of its offshore cays (i.e., Cayo Botella, Cayo 
Agua, Cayo Lobito, Cayo Yerba).
    However, protected habitat does not ensure persistence of skinks, 
particularly if nonnative mammals are present. Rather, it suggests that 
habitat destruction or modification in those areas is minimal and less 
than for habitat that is not protected. For example, the Culebra skink 
was historically reported from Culebrita Island (part of the Culebra 
NWR) but is currently considered likely extirpated, most likely due to 
presence of rats.

Cumulative Effects

    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the SSA report, we have 
analyzed the cumulative effects of identified threats and conservation 
actions on the species. To assess the current and future condition of 
the species, we evaluate the effects of all the relevant factors that 
may be influencing the species, including threats and conservation 
efforts. Because the SSA framework considers not just the presence of 
the factors, but to what degree they collectively influence risk to the 
entire species, our assessment integrates the cumulative effects of the 
factors and replaces a standalone cumulative-effects analysis.

Current Condition Methods

    We considered all skinks within each island or cay (i.e., outside 
of mainland Puerto Rico) to be single populations. We assume that each 
island is geographically isolated and the influences on and threats to 
Caribbean skinks tend to occur to entire islands

[[Page 103948]]

(e.g., nonnative predators are either present or not present). 
Geographic ranges (i.e., islands considered in these analyses outside 
of the main island of Puerto Rico) are based on current and historical 
records of each species.
    As for the other Caribbean skink species, limited information is 
available on the distribution of Puerto Rican skinks on the main island 
of Puerto Rico. Therefore, we delineated the populations of the Puerto 
Rican skink on the main island using the recently (2021-2023) collected 
survey and genetic information to discern what areas could constitute 
separate populations (Rivera et al 2023, pp. 15-16). Genetic 
information was obtained via tail clips during surveys. We overlayed 
populations with potential habitat identified by the Puerto Rico GAP 
Analysis Project (PRGAP) for the species (Gould et al. 2008, p. 91). 
Predicted habitat from the GAP model utilized landcover types (i.e., 
dry forest, woodland, and shrublands) in 2001 that were restricted to 
at or below 300 m and the few point locations for skinks that were 
available in 2006. The model is likely not comprehensive given the low 
number of confirmed skink observations that were available in 2006 and 
does not include the urban development that has occurred on the main 
island of Puerto Rico since 2001; we modified the model to include 
habitats below 500 m based on more recent survey locations and combined 
it with more recent genetic information from 2021-2023.
    Numerous islands with historical skink records have not been 
surveyed recently, and it is possible that additional individuals and 
populations are present on these islands or even other islands in the 
Caribbean. Current data suggest that these species are habitat 
generalists. Some areas are likely not suitable as habitat for skinks, 
for example, entirely developed urban areas. However, skinks are also 
known to occur within some developed and rural areas, particularly if 
adjacent to suitable habitat. Thus, we considered an island with 
documented occurrences as a single population, except for mainland 
Puerto Rico, and we assessed habitat conditions based on 
characteristics of the entire island. On mainland Puerto Rico, we 
determined population status based on confirmed occurrence information 
and amount of potential habitat as determined by the Puerto Rico GAP 
analysis predicted habitat (Gould et al. 2008, p. 91); these 
populations were confirmed using the survey and genetic information 
(Rivera et al. 2023, pp. 15, 16). Survey methodology and reporting has 
varied significantly from population to population. Even with the same 
methodology and reporting, survey success can differ based on external 
factors like weather conditions, surveyor experience, detection 
probabilities, threats, or habitat conditions. All these factors 
contribute to high levels of uncertainty in the presence or absence of 
skinks within a population.
    For each island population, we considered the population ``extant'' 
if skinks have been detected there since 2000. The threshold of 
detection before and after 2000, along with a Bayesian estimate of 
occurrence, which is a probabilistic model linking skink occurrence to 
several variables, such as predator presence, island size, maximum 
elevation, habitat class, human population size, and co-occurring 
species (see section 5.1.1 of SSA report (Service 2023, pp. 57-59), 
allows for a more conservative estimate of occurrence (i.e., avoidance 
of classifying a population as extirpated when it is, in fact, extant). 
Because extensive surveys have not occurred on islands within the 
geographic ranges of many of the Caribbean skink species, we utilized 
Bayesian analyses to assess likelihood of skink existence on individual 
smaller islands (<5 square kilometers (km\2\) (500 ha)) with detections 
pre-2000 to assess if a skink population likely currently occurs there. 
If a smaller island was known to be occupied by skinks before 2000 and 
had a Bayesian probability score of <=0.49, then we considered the 
status of that island ``likely extirpated'' and if the score is >=0.50, 
we considered the status ``unknown.'' The exception to this was when 
islands had been extensively surveyed since 2000 and there have been no 
detections. Caribbean skinks are cryptic and difficult to detect, and 
the potential habitats on the larger islands are often difficult to 
access or survey thoroughly, and predators on some larger islands have 
seemingly already eliminated skinks (i.e., St. Thomas, St. John, and 
St. Croix). Additionally, there are few case studies for larger islands 
for the Bayesian analysis, and the resulting network (i.e., output from 
analysis) linking variables did a poor job predicting probability of 
existence on islands >5 km\2\ (500 ha); therefore, we did not try to 
estimate status of populations on larger islands and considered all 
islands >5 km\2\ with detections from between 1970 and 2000 to have an 
``unknown'' status (see table 5.2 of the SSA report (Service 2023, p. 
61)).
    Resiliency is the ability of a species to withstand environmental 
stochasticity which is normal, year-to-year variations in environmental 
conditions, as well as demographic stochasticity; typically, the larger 
a population and the more individuals present, the more resilient the 
population. We assume that current threat levels influence the current 
population size; in other words, threats acting negatively on a 
population can reduce the overall size of the population, which can 
then result in a lower ability to withstand environmental and/or 
demographic stochasticity. Population size is typically used as a 
reliable indicator of overall resiliency. Due to the cryptic nature of 
Caribbean skinks and lack of research and survey data, demographic data 
(i.e., presence/absence, abundance, population trends, population 
structure) are lacking in most locations. Therefore, the resiliency of 
the populations relies on habitat metrics such as level of habitat 
protection, nonnative predator pressure, and risk from storm surge.
    Resiliency scores were generated by combining scores for three 
habitat metrics (Protection, Nonnative Predators, Storm Surge Risk). 
Each island was assigned a level of habitat protection based on 
ownership (public/private) and percentage area protected, which 
represents development risk, and the size of the island. Protected area 
percentages were assessed using the Protected Areas Database (PAD-US), 
the Puerto Rico Protected Areas Database, and the World Database for 
Protected Areas (WDPA) (UNEP-WCMC 2024, unpaginated; USGS 2022, 
unpaginated; Caribbean Landscape Conservation Cooperative 2016, 
unpaginated).
    The presence of nonnative predators is an important influence on 
Caribbean skinks, especially when islands are small. Mongooses are 
known to be especially harmful to small reptiles, particularly in 
island habitats. The larger the island, the more complex the ecosystem 
due to a larger diversity of habitats, which can provide multiple patch 
areas and refugia, more diverse prey items for nonnative predators, and 
potentially a larger population of skinks (Simberloff 1974, entire; 
Kohn and Walsh 1994, entire). It is difficult to know when an island is 
``large enough'' so that skinks can persist alongside the presence of 
nonnative predators, particularly mongooses. The smaller the island, 
the greater the impact of nonnative predators, including rats. We 
scored the level of predator pressure for each island based on the type 
of nonnative predator present and the size of the island. Islands 
smaller than 15 ha were considered likely extirpated due to a higher 
risk of predator dispersal.
    Finally, we determined the potential impact of storm surges on 
skink populations. Storm surge heights were

[[Page 103949]]

estimated using the sea, lake, and overland surges from hurricanes 
(SLOSH) model used by the National Weather Service (Jelesnianski et al. 
1992, entire). All simulated hurricanes had a forward speed of 15 miles 
per hour (the closest simulation option to the average hurricane speed 
of 10.8 miles per hour at 15-20 degrees north latitude; NOAA 2014, 
unpaginated) in a northwesterly direction, the primary direction of 
hurricane movement in the skinks' range. The SLOSH model predicts 
average storm surge heights for multiple trajectories of a hurricane of 
the same strength, speed, direction, and tide to account for 
uncertainty in the path of any one storm. To determine potential 
maximum impact for storm surge on each island, we simulated Category 5 
hurricanes at mean tide level. For each simulated storm surge, we 
calculated the percent of each island or cay that lies below that 
elevation and would thus be inundated (or potentially flooded in cases 
where lower elevation areas are inland and surrounded by higher 
elevation areas) (see appendix A of the SSA report (Service 2023, pp. 
141-145)). Note that scoring for the island of Puerto Rico is 
considered to be ``no effect'' because the skink populations on Puerto 
Rico are inland at high elevations and therefore not prone to the same 
effect from storm surges as other islands (and therefore skink 
populations) in the Caribbean.
    The best available information for each population was gathered 
from the literature, data sources, and species experts. Each metric was 
weighed equally. Ultimately, resiliency classifications relied on 
habitat conditions, as affected by threats. For each metric, 
populations were assigned a score of -1, 0, or 1, as described below in 
table 1.

     Table 1--Scoring of Habitat Factors To Determine Population Resiliency of Eight Caribbean Skink Species
----------------------------------------------------------------------------------------------------------------
                                                                   Habitat metrics
                                    ----------------------------------------------------------------------------
               Score                                           Nonnative predator
                                       Habitat protection           pressure               Storm surge risk
----------------------------------------------------------------------------------------------------------------
-1.................................  Low...................  High..................  High: >25% inundated from
                                                                                      category 5 hurricane.
0..................................  Moderate..............  Low...................  Low: <25% inundated from
                                                                                      category 5 hurricane.
1..................................  High..................  No impact.............  No effect for main island
                                                                                      Puerto Rico.
----------------------------------------------------------------------------------------------------------------

    The scores for all habitat metrics were summed, and final relative 
population resiliency categories were assigned to each population 
(except those that are likely extirpated). The range of final scores 
was evenly divided into the four possible categories: High, Moderate, 
Low, and Likely Extirpated. Likely extirpated means that all the 
habitat factors are unfavorable for skink viability and the population 
is/would be likely extirpated. A low score means that multiple 
resiliency factors are not favorable for skink viability. Moderate or 
high scores indicate that multiple habitat factors are conducive to 
skink population viability on a given island.
    Redundancy reduces the species' extinction risk if a portion of the 
species' range is negatively affected by a natural or anthropogenic 
catastrophic disturbance. For a Caribbean skink species to withstand 
catastrophic events such as hurricanes or the introduction of nonnative 
predators, it needs to have multiple, sufficiently resilient 
populations across its range. We used the Bayesian probability to 
determine likelihood of existence for each of the islands with 
historical or current populations to assess redundancy for each 
species. As described above, the status of the species on each of the 
islands (extant, likely extirpated, unknown) allowed the assessment of 
redundancy for each species.
    Most of the Caribbean skink species exhibit limited distribution 
(except Puerto Rican skink) and relative geographic rarity (see 
appendix E of the SSA report (Service 2023, pp. 174-196)). Despite 
these circumstances, they appear to use a wide variety of habitat and 
structure across islands. They also appear moderately tolerant of human 
infrastructure and disturbance (e.g., removal of unexploded ordnance 
(Puente-Rol[oacute]n and Vega-Castillo 2019, p. 12)), with the 
exceptions of introduced nonnative predators and direct loss of 
habitat. There also appear to be no known restrictions to movement 
throughout the year.
    In some cases, genetic representation is limited to a single or 
very few small islands, while others are represented by multiple 
populations on large islands and scattered outlying cays; thus, the 
catastrophic loss of a single island might have substantially different 
effects on genetic and geographic representation depending on the 
species. For instance, the Puerto Rican skink has multiple populations, 
some on a single large island and at least one on a smaller island; 
therefore, risk associated with catastrophic events (e.g., particularly 
strong hurricanes and associated storm surge) would likely be 
distributed across more populations and complete loss of genetic 
diversity is less likely. However, loss of some populations could 
reduce genetic diversity of this species.
    The Mona skink is distributed on a single large island with both 
higher elevation and lower elevation sites closer to the coast, while 
other species, such as Culebra skink, Lesser Virgin Islands skink, and 
Virgin Islands bronze skink, have populations on several small, low-
elevation islands. In species where few, small islands contain all 
known genetic diversity or where a substantial proportion of sites are 
located on small islands, risk of losing existing representation and 
redundancy is likely higher. For instance, catastrophic events (e.g., 
particularly strong hurricanes, storm surge, and overwash) could 
eliminate a much higher percentage of the existing genetic diversity 
within a species if localized skink populations are lost or are 
represented by only a single location on a small cay or if sea level 
rise acts with storm surge to remove several small islands over time. 
Such events could reduce species-level adaptive potential, limiting 
future ability to respond to changing environmental conditions (Service 
2021, pp. 4-5). In addition, many of the traits are still unknown at 
this time for these species (e.g., population size, competitive 
ability, site fidelity, age structure, recruitment rate, etc. (Thurman 
et al. 2020, entire)). Therefore, at present we have an incomplete 
picture of adaptive capacity for each of the species, and additional 
knowledge about these traits could further refine our understanding of 
representation.

Future Conditions Methods

    The primary threats to Caribbean skinks in the future are: (1) 
habitat destruction and modification, (2) nonnative predators, and (3) 
climate change, specifically SLR, and the increases in intensity, 
frequency, and duration of hurricane activity. Due to a lack of survey 
effort in many locations and the cryptic nature of these species,

[[Page 103950]]

we assessed the future condition of the habitat quality on islands that 
have current or historical documentation of skink occurrences. We 
predicted resiliency at three future time points: 2050, 2070, and 2100. 
We considered the same metrics as current condition (habitat 
protection, predator pressure, risk from storm surge) as well as 
predicted SLR for each scenario.

       Table 2--Scores of Habitat Metrics To Determine Future Resiliency of Eight Caribbean Skink Species
----------------------------------------------------------------------------------------------------------------
                                                                  Habitat metrics
                                 -------------------------------------------------------------------------------
              Score                                   Nonnative predator    Sea level rise
                                  Habitat protection       pressure              (SLR)            Storm surge
----------------------------------------------------------------------------------------------------------------
-1..............................  Low...............  High (extirpation   High: >25%          High: >25%
                                                       likely on islands   inundated from      inundated from
                                                       <15 ha).            SLR or SLR +        SLR + storm
                                                                           storm surge.        surge.
0...............................  Moderate..........  Low...............  Moderate or Low:    Moderate or Low:
                                                                           <25% inundated      >10% but <25%
                                                                           from SLR or SLR +   inundated from
                                                                           storm surge.        SLR + storm
                                                                                               surge.
                                                                         ---------------------------------------
1...............................  High..............  No impact.........    No effect (Puerto Rico main island
                                                                                           only).
----------------------------------------------------------------------------------------------------------------

    For each influence on future resiliency of each Caribbean skink 
species (extant populations only), we scored each habitat factor (table 
2), as previously described for current condition, and calculated final 
scores to determine the future resiliency of each population, under 
four possible scenarios (table 3).

      Table 3--Future Scenarios To Determine the Resiliency of Populations of Eight Caribbean Skink Species
----------------------------------------------------------------------------------------------------------------
                                                               Nonnative predator       Sea level rise (SLR) +
              Scenario                 Habitat protection           pressure               storm surge risk
----------------------------------------------------------------------------------------------------------------
1A.................................  same as current.......  same as current.......  Intermediate SLR + Cat3 *
                                                                                      (2050).
                                                                                     Intermediate SLR + Cat5 *
                                                                                      (2070 & 2100).
1B.................................  same as current.......  increased pressure....  Intermediate SLR + Cat3
                                                                                      (2050).
                                                                                     Intermediate SLR + Cat5
                                                                                      (2070 & 2100).
2A.................................  same as current.......  same as current.......  High SLR + Cat5.
2B.................................  same as current.......  increased pressure....  High SLR + Cat5.
----------------------------------------------------------------------------------------------------------------
* Cat3 = Category 3 hurricane; Cat5 = Category 5 hurricane.

Scenario 1A

    Under scenario 1A, conditions continue along their current 
trajectory. The risk of human development (measured here as level of 
habitat protection) remains the same as current, and populations that 
are currently impacted by the associated stressors from development 
remain negatively impacted by these threats. Under this scenario, we 
calculated impacts under the Intermediate SLR scenario as well as the 
additional storm surge risk from a Category 3 hurricane (2050 only) and 
Category 5 hurricane (2070 and 2100), which are expected to represent a 
higher proportion of hurricanes in the Caribbean into the future 
(Service 2023, pp. 52-55).

Scenario 1B

    Under Scenario 1B, there is an increase in predator pressure on 
islands where nonnative predators do not currently occur. Impacts to 
small islands not currently impacted by nonnative predators include the 
theoretical introduction of nonnative mammalian predators, most likely 
rats, which can have a profound negative effect on skinks on smaller 
islands/cays. Because larger islands will continue to have nonnative 
predators, the risk will remain unchanged on those islands. The risk of 
human development (i.e., level of habitat protection) remains the same 
as current because we do not have data to inform this metric in the 
future (note, this metric is held constant for all future scenarios). 
Under this scenario, we calculated impacts under the Intermediate SLR 
scenario as well as the additional storm surge risk from a Category 3 
hurricane (2050 only) and Category 5 (2070 and 2100), which are 
expected represent a higher proportion of hurricanes in the Caribbean 
into the future.

Scenario 2A

    Under Scenario 2A, habitat protection and nonnative predator risk 
remain status quo, and SLR and storm surge calculations are based on 
the High SLR scenario and the storm surge risk from Category 5 
hurricanes for all time iterations.

Scenario 2B

    Under scenario 2B, impacts of nonnative predators, SLR, and storm 
surge worsen. Impacts to small islands not currently impacted by 
nonnative predators include the theoretical introduction of nonnative 
mammalian predators. Because larger islands will continue to have 
nonnative predators, the risk will remain unchanged on those islands, 
but we expect the impacts to continue to increase since eradication is 
not feasible and exacerbated as human population sizes increase; 
therefore, this scenario includes the lowering of habitat protection 
category by one level. For this scenario we calculated impacts using 
the High SLR scenario as well as the additional storm surge risk from 
Category 5 hurricanes.

Puerto Rican Skink

    Here, we present both current and future condition analyses results 
for the Puerto Rican skink. There are currently four known extant 
Puerto Rican skink populations on the island of Puerto Rico and one on 
the island of Desecheo. Historical records indicate that Puerto Rican 
skinks likely occurred on Icacos (1932) and Vieques (1980; figure 2.16; 
Hedges and Conn 2012, p. 186), and on the main island of Puerto Rico 
skinks were historically collected in and around San Juan (in 1879, 
1880) and Bayam[oacute]n (in 1919, 1931); the southern coastal areas 
including Ensenada (in 1915, 1919), North Descalabrado (in 1967), and 
Cerro del Muerto (in 1980); Cape San Juan (in 1931) which is in extreme 
northeastern Puerto Rico; and Barrio Coto in the municipality of

[[Page 103951]]

Isabela (in 1966), which is near Quebradillas (Hedges and Conn 2012, p. 
186). Skink populations in San Juan and Cape San Juan are considered 
historical and are designated as likely extirpated in our analyses. 
Three skink specimens, one from Culebra, another from Cayo Norte, and 
one from Cayo Luis Pe[ntilde]a in Culebra, were also assigned to the 
Puerto Rican skink species; however, there is no genetic information 
for these three specimens to confirm if Puerto Rican skinks are 
sympatric with Culebra skinks. Unlike other island populations of 
skinks, which are much smaller than those on the main island of Puerto 
Rico, we treat each skink population on the main island of Puerto Rico 
separately regarding amount of predator pressure and level of 
protection.

Habitat Protection

    For level of protection, we describe the total percentage protected 
and indicate the percentage that includes the Zona de 
Conservaci[oacute]n del Carso (Karst Conservation Zone) due to 
differences in protection levels as compared to other protected areas. 
This zone includes both public and privately owned lands, and 
conservation within this zone cannot be considered conclusive since 
permits for certain activities within this zone are subject to PRDNER 
evaluation and there is uncertainty if activities will be allowed or 
not.
    Most of the information for the Quebradillas population is from 
near and in the Guajataca Commonwealth Forest, which is a subtropical 
moist forest occurring within the karst landscape in the northwestern 
municipality of Isabela, Puerto Rico. The Quebradillas population 
encompasses almost ~42,000 ac (17,000 ha) of predicted habitat, with 73 
percent of that area with varied protection designations (67 percent 
Karst Conservation Zone, 6 percent other protected areas (Service 2023, 
pp. 74-76)). The high habitat protection in this area is considered to 
provide a lower development risk, primarily due to restricted 
development within the Karst Conservation Zone.
    The southwest population overlaps with several municipalities where 
skinks have been documented, particularly within and around the 
southern portions of the Maricao Commonwealth Forest (San Germ[aacute]n 
and Sabana Grande within humid subtropical forests; Rivera et al. 2023, 
p. 10). This large area of predicted habitat (92,986 ac (37,630 ha)) 
has 22 percent (6 percent within Karst Conservation Zone, 16 percent 
other protected areas) of that area being protected.
    The third population occurs in south central Puerto Rico in the 
municipality of Ponce. Of the 6,155 ac (2,491 ha) of predicted habitat 
in the area, very little is protected (approximately 1 percent); 
therefore, development risk is high.
    In 2022, a skink was collected inside a garage in north central 
Puerto Rico in the municipality of Florida, an area where skinks had 
not been detected in the past but includes 19,714 ac (7,978 ha) of 
predicted skink habitat. A large percentage of this potential habitat 
is currently protected (88 percent). Of the area protected, 78 percent 
is within the Karst Conservation Zone and 10 percent is within other 
protected areas.
    Outside of the main island, the only other population known to be 
extant is on the island of Desecheo off the west coast of Puerto Rico. 
During surveys in 2010, 2012, and 2016, researchers observed skinks 
that are presumed to be Puerto Rican skinks (Wolf et al. 2010, p. 5; 
Herrera-Giraldo and Bermudez 2010, p. 22; Figuerola 2023, pers. comm.). 
The entire island is a National Wildlife Refuge (NWR) with no 
development risk.

Predator Pressure

    Because the main island of Puerto Rico is occupied by nonnative 
predators including mongooses, rats, cats, etc., the influence of 
predator pressure on population resiliency is always present and 
therefore considered high risk to skinks in all main island 
populations. Nonnative predators have been eradicated from Desecheo; 
therefore, there is currently no impact from predator pressure for this 
population.

Storm Surge Risk

    The populations on the main island of Puerto Rico occur inland and 
are not influenced by storm surge. In addition, Desecheo is an island 
with high elevation; therefore, skink populations there are not 
impacted by the effects of storm surge.

Current Condition Summary

    Currently, five of nine (56 percent) known populations are extant, 
while four (44 percent) are considered likely extirpated (table 4). One 
population (Desecheo) is in high resiliency condition, and two 
(Quebradillas and Florida) are in moderate resiliency condition, and 
these populations are distributed across the northern part of the 
species' range on Puerto Rico and Desecheo Island; the remaining two 
populations (Southwest and Ponce) have low resiliency (table 4). 
Habitat for all populations is generally located at elevations that are 
not at risk of storm surge or sea level rise. Development is a risk to 
all populations. Because the main island of Puerto Rico is occupied by 
nonnative predators including mongoose, rats, cats, and dogs, the 
influence of predator pressure on population resiliency is always 
present and therefore considered high risk to skinks. In addition, all 
current populations are geographically isolated at considerable 
distance from one another; therefore, it will be difficult for a high 
or moderate condition population to supplement or rescue another 
population affected by threats. Thus, current redundancy is low for the 
Puerto Rican skink.
    Given the reduction in historical range, representation has also 
been reduced from historical condition. However, current populations 
exist in multiple locations in several different habitat types across 
Puerto Rico and on Desecheo Island. Based on the genetic analysis, the 
populations on Puerto Rico may range from small to large effective 
population sizes with potential for admixture, although there is some 
evidence of inbreeding within the Florida population (Rivera et al. 
2023, p. 20). This apparent genetic diversity across Puerto Rican skink 
populations contributes to the species' overall adaptive capacity, 
giving the species the potential to adapt when faced with changes in 
its current or future environment.

                                                 Table 4--Puerto Rican Skink Current Resiliency Summary
 [Numbers in parentheses are metric scores (see table 1), summed to provide overall resiliency. NA = not applicable, as likely extirpated populations do
                                                                  not have resiliency.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Population                Habitat protection       Predator pressure    Risk from storm surge          Status               Resiliency
--------------------------------------------------------------------------------------------------------------------------------------------------------
Icacos.............................  High (1)..............  High (-1).............  High (-1)............  Likely extirpated....  NA.
Desecheo...........................  High (1)..............  No Impact (1).........  Low (0)..............  Extant...............  High (2).
Vieques............................  High (1)..............  High (-1).............  Low (0)..............  Likely extirpated....  NA.

[[Page 103952]]

 
Main Island, PR
    San Juan.......................  Low (-1)..............  High (-1).............  Low (0)..............  Likely extirpated....  NA.
    Cape San Juan..................  Moderate (0)..........  High (-1).............  Low (0)..............  Likely extirpated....  NA.
    Quebradillas...................  High (1)..............  High (-1).............  No effect (1)........  Extant...............  Moderate (1).
    Southwest......................  Low (-1)..............  High (-1).............  No effect (1)........  Extant...............  Low (-1).
    Ponce..........................  Low (-1)..............  High (-1).............  No effect (1)........  Extant...............  Low (-1).
    Florida........................  High (1)..............  High (-1).............  No effect (1)........  Extant...............  Moderate (1).
--------------------------------------------------------------------------------------------------------------------------------------------------------

    As part of the SSA report, we also developed future-condition 
scenarios to capture the range of uncertainties regarding future 
threats and the projected responses by the Puerto Rican skink. Our 
scenarios assumed nonnative predators and further fragmentation from 
development are the main risks to populations on Puerto Rico and the 
only future threat to the population on Desecheo would be if predators 
are introduced, which would cause reduced resiliency (note: it is 
highly unlikely that mongooses would ever be introduced). Because we 
determined that the current condition of the Puerto Rican skink is 
consistent with the Act's definition of an endangered species (see 
Determination of Status--Puerto Rican Skink, below), we are not 
presenting the results of the future scenarios in this proposed rule. 
Please refer to the SSA report (Service 2023, pp. 79-82) for the full 
analysis of future scenarios.

Mona Skink

    The Mona skink is historically and currently known only from Mona 
Island, a 13,838-ac (5,600-ha) island off the west coast of Puerto 
Rico. The entire island is a designated nature preserve protected and 
managed by the PRDNER. The Mona skink has been consistently detected on 
the island over time, with the earliest known detection in 1894 to more 
recent detections in 2021. The species is readily observed on Mona 
Island, indicating this singular population has maintained a level of 
resiliency to withstand stochastic events over time. Although the 
species is limited to one island, there are multiple, interconnected 
habitat patches occupied across the island (Rivera et al. 2023, p. 12). 
The species occupies interior areas of the island, which are not 
subject to storm surge or sea level rise. These habitat patches that do 
not experience SLR and storm surge threats likely ensure that the 
species is less susceptible to catastrophic events; however, the 
species is still vulnerable to other unknown threats given that its 
range is limited to one island. The one population on Mona Island 
houses all known genetic diversity for the species; however, genetic 
evidence is insufficient to determine the level of genetic diversity.
    The primary threat driving species' viability is nonnative 
predators. Mona Island is currently occupied by nonnative predators 
(cats and rats). There are no mongooses or dog predators on the island. 
Given the larger size of the island and the fact that mongooses are not 
present, predator pressure was assessed as low for the species. Low 
does not mean there is no predator pressure but a lower level of 
predator pressure from cats and rats. Mona Island has a maximum 
elevation of over 296 feet (ft) (90 meters (m)) and, therefore, most of 
the island is not susceptible to impacts from storm surge or sea level 
rise like other low-lying islands. Mona Island has high habitat 
protection given it is protected and managed by PRDNER, and therefore 
there are no current impacts from development pressure.
    The current resiliency of the one Mona skink population is moderate 
(table 5). Though the species is known only from Mona Island and is 
considered a single population, habitat patches are occupied across the 
island, and the species occupies interior as well as coastal areas of 
the island. Although the species is impacted by some threats across the 
range, the Mona skink exhibits sufficient resiliency, redundancy, and 
representation to support the species' viability.

                                                     Table 5--Mona Skink Current Resiliency Summary
                             [Numbers in parentheses are metric scores (see table 1), summed to provide overall resiliency.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Population                Habitat protection       Predator pressure    Risk from storm surge          Status               Resiliency
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mona Island........................  High (1)..............  Low (0)...............  Low (0)..............  Extant...............  Moderate (1)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In considering future threats to the species, nonnative predators 
are the primary driver to the species' viability in the future. Given 
the larger size of the island, and that mongooses are not likely to be 
introduced, predator pressure was assessed as low in the future for the 
species. Nonnative predator introductions would be expected to reduce 
skink numbers on the island, but there are a diversity of habitats and 
patches, and it is a large island; therefore, predation risk is not 
likely to eliminate the known population, nor do we expect it to reduce 
to low resiliency condition in the future. Impacts from climate change 
in the future were also assessed as low given the higher elevation of 
the island. Further, impacts of development pressure to the species are 
low as Mona Island has high habitat protection given it is protected 
and managed by PRDNER.

[[Page 103953]]



                                                 Table 6--Mona Skink Future Resiliency Summary for Four Future Scenarios Under Three Time Steps
                                                                                         [M = moderate]
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                 Current                                                   2050                                    2070                                    2100
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                  Status                             Resiliency              1A        1B        2A        2B        1A        1B        2A        2B        1A        1B        2A        2B
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Extant....................................  M...........................        M         M         M         M         M         M         M         M         M         M         M         M
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    The projected future resiliency of skinks on Mona Island is 
assessed as moderate (table 6), given the future level of threats to 
the species. The future range of the Mona skink is limited to one 
island; however, it is still expected to have moderate resiliency to 
withstand stochastic events. Although the species is impacted by 
several threats across the range, the Mona skink exhibits sufficient 
resiliency, redundancy, and representation to support the species' 
future viability.

Culebra Skink

    The Culebra skink currently occupies five islands including Culebra 
and several of the small cays surrounding Culebra Island. Culebra 
skinks were historically found on Isla Culebrita, the largest cay near 
Culebra, but they have not been seen there since 1936 likely because it 
is a small to medium sized island with nonnative predators. 
Observations on the cays surrounding Culebra Island, including Cayo 
Agua, Cayo Botella, Cayo Lobito, and Cayo Yerba are recent (since 
2017).
    The small cays currently occupied by skinks are very small (<10 ac 
(<4 ha)), are not currently occupied by any nonnative predators, and 
are protected from development. Much of the land on each cay is low 
elevation (i.e., less than 33 ft (10 m)) making them susceptible to 
storm surge, with projected Category 3 storms at 5 ft (1.52 m) and 
Category 5 storms at 6 ft (1.83 m) (see table 8.3 and appendix A of the 
SSA report; Service 2023, pp. 92, 142). Culebra Island is inhabited by 
people, and there is development on parts of the island, except in 
areas that are protected, primarily within the Culebra NWR. Although 
mongooses have not been observed, other nonnative predators including 
cats and rats occur there. Culebra Island has a higher average 
elevation (~646 ft (197 m)) than the smaller cays and is less 
susceptible to storm surge risk currently.
    Each of the small cays currently occupied by Culebra skinks is 
relatively similar; each cay is protected and not currently occupied by 
nonnative mammalian predators. However, because they each have low 
elevations and are small in size, the risk of impacts from storm surge 
is high, and therefore they currently have moderate resiliency (table 
7). Even though the Culebra skink on Culebra Island is less impacted by 
storm surge and has large tracts of protected areas, it has moderate 
current resiliency because several nonnative predators occupy the 
island. In addition, skinks occur partially on unprotected lands, which 
are vulnerable to development.

                                                    Table 7--Culebra Skink Current Resiliency Summary
 [Numbers in parentheses are metric scores (see table 1), summed to provide overall resiliency. NA = not applicable, as likely extirpated populations do
                                                                  not have resiliency.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Population                Habitat protection       Predator pressure    Risk from storm surge          Status               Resiliency
--------------------------------------------------------------------------------------------------------------------------------------------------------
Isla Culebrita.....................  High (1)..............  Low (0)...............  Low (1)..............  Likely extirpated....  NA
Cayo Botella.......................  High (1)..............  No impact (1).........  High (-1)............  Extant...............  Moderate (1)
Cayo Agua..........................  High (1)..............  No impact (1).........  High (-1)............  Extant...............  Moderate (1)
Cayo Lobito........................  High (1)..............  No impact (1).........  High (-1)............  Extant...............  Moderate (1)
Cayo Yerba.........................  High (1)..............  No impact (1).........  High (-1)............  Extant...............  Moderate (1)
Culebra............................  Moderate (0)..........  Low (0)...............  Low (0)..............  Extant...............  Moderate (0)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Currently, the Culebra skink has multiple populations in moderate 
resiliency condition across its known range (table 7). The number and 
distribution of these sufficiently resilient populations enable the 
species to withstand both stochastic and catastrophic events. The range 
is not large, and many of the islands are small, but the species 
currently has substantial genetic representation in the form of 
separate islands.

                                              Table 8--Culebra Skink Current and Future Resiliency Summary
                      [NA = not applicable, as likely extirpated populations do not have resiliency; M = moderate; X = extirpated.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                               Current                            2050                         2070                       2100
          Population           -------------------------------------------------------------------------------------------------------------------------
                                      Status           Resiliency       1A     1B      2A     2B      1A     1B     2A     2B    1A     1B    2A     2B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Isla Culebrita................  Likely extirpated  NA...............  .....  ......  .....  ......  .....  ......  ....  .....  ....  .....  ....  .....
Cayo Botella..................  Extant...........  Moderate.........  M      X       M      X       M      X       X     X      X     X      X     X
Cayo Agua.....................  Extant...........  Moderate.........  M      X       M      X       M      X       M     X      M     X      X     X
Cayo Lobito...................  Extant...........  Moderate.........  M      X       M      X       M      X       M     X      M     X      M     X
Cayo Yerba....................  Extant...........  Moderate.........  M      X       M      X       M      X       M     X      M     X      X     X
Culebra.......................  Extant...........  Moderate.........  M      Low     M      Low     M      Low     M     Low    M     Low    M     Low
--------------------------------------------------------------------------------------------------------------------------------------------------------

    By 2050, resiliency of each of the populations will change only if 
predator pressure is increased (see ``B'' scenarios in table 8). Since 
most of the populations are on small cays, the addition of a predator 
will almost certainly mean the extirpation of skinks within a short 
time. Results are similar for 2070 except Cayo Botella will

[[Page 103954]]

become too small to support a population of skinks under the High SLR 
scenario (Scenario 2A, table 8). By 2100, nearly all the small cays 
(except for Cayo Lobito) will be classified as extirpated under the 
High SLR scenario (Scenario 2A) and skinks on Cayo Botella will likely 
be extirpated under both Intermediate and High SLR scenarios (table 8). 
The main risk on the main island of Culebra is the increased predator 
pressure and continued habitat modification. The addition of any 
predator to the small cays would likely lead to the skinks being 
quickly extirpated.
    Future redundancy and representation of Culebra skink is expected 
to be reduced by 2100 under most scenarios, ultimately with the loss of 
smaller cays due to a combination of predator introduction and SLR/
storm surge. Only two populations are expected to remain (Culebra and 
possibly Cayo Lobito) by 2100 if predators are not introduced to the 
small cays; therefore, redundancy at 2100 would be limited. There is 
evidence of genetic clustering (i.e., grouping of similar genes) 
between populations on Culebra, but the actual genetic structure of 
skinks on Culebra is still largely unknown (Rivera et al. 2023, p. 15). 
Culebra has some diverse habitats, and skinks have been seen in both 
the coast and upland forests. Coastal areas will likely be impacted by 
sea level rise. Therefore, representation is expected to be 
substantially reduced across the range by 2100 under three of four 
future scenarios.

Greater Virgin Islands Skink

    The Greater Virgin Islands skink is believed to be historically 
distributed in the USVI on St. John and St. Thomas (Hedges and Conn 
2012, p. 210). It is possible that the Greater Virgin Islands skink 
occurred in the BVI as well. The species likely had patchy distribution 
across its range, and its small size, cryptic coloration, and secretive 
behavior could account for its lack of detection. If observed, it could 
be misidentified as the sympatric Lesser Virgin Islands skink or Virgin 
Islands bronze skink, but lack of observations of any skinks on St. 
John or St. Thomas make misidentification less probable.
    The Greater Virgin Islands skink has not been seen in nearly 150 
years since the last specimen was cataloged in 1877, despite 
considerable herpetological survey work through the Virgin Islands 
(Hedges and Conn 2012, p. 210). There are six known museum specimens, 
collected in 1779-1799, 1834, 1845-1846, and 1877 (Hedges and Conn 
2012, p. 207). Because the species has long been believed to be 
extirpated from the main islands of St. John and St. Thomas, not many 
targeted surveys have been undertaken to look for skinks on either 
island. From 1986 to 2023, qualified researchers and wildlife agency 
staff invested considerable efforts in looking for other herpetofauna 
that would almost certainly document opportunistic encounters of any 
herp species, and no known documentation of skinks exist (Service 2023, 
pp. 150-151). Herp survey efforts on St. Thomas do not appear to be as 
extensive as those on St. John, but optimal habitat on St. Thomas is 
known to be fragmented by extensive human development (Platenberg and 
Harvey 2010, p. 548), and the consensus from the herpetology community 
is that there are no known skinks on the island of St. Thomas. Given 
what is known about the life history and habitat associations of 
Spondylurus skinks, it is reasonable to assume that skinks would have 
been detected given the extent of survey efforts in optimal habitats on 
both islands of St. Thomas and St. John (see chapter 9 and appendix B-I 
of the SSA report (Service 2023, pp. 100, 146-152)).
    Skinks that once occurred on the islands of St. Thomas and St. John 
faced a primary threat from the introduced mongoose, a predator that 
has been implicated in the extinction of the Greater Virgin Islands 
skink (Hedges and Conn 2012, p. 210; Hedges 2013, p. 1). The invasive 
predator was introduced as a biological control of rats in sugar cane 
fields in the late nineteenth century, immediately resulting in a mass 
extinction of skinks and other reptiles (Hedges and Conn 2012, p. 4). 
The ground-dwelling and diurnal habits of skinks make them particularly 
susceptible to mongoose predation.
    Based on the best scientific and commercial information available, 
it is highly unlikely that an individual of Greater Virgin Islands 
skink could be extant but undetected; therefore, we presume that the 
species is likely extinct.

Lesser Virgin Islands Skink

    Lesser Virgin Islands skink was historically known to occur on 15 
islands within the USVI and BVI. The populations on three historically 
occupied islands, making up approximately 43 percent of the species' 
historical range, are considered likely extirpated, including St. 
Thomas, the largest island in the USVI, and two islands in BVI (Necker 
Island and Great Camanoe Island). The status of seven populations 
(Capella Island, Buck Island (St. Thomas), Little Thatch Island, Fallen 
Jerusalem, Salt Island, Round Rock Island, and Ginger Island) are 
currently unknown, primarily because recent surveys have not been 
conducted, and very little information is known about these islands. 
However, there is a high likelihood that skinks could be extirpated on 
these islands given the nonnative predator threat on surrounding 
islands and the short distance of the seven islands to those with known 
predator presence. Given the potential for these threats and likely 
extirpation of skinks, we assumed that these seven unknown populations 
do not contribute to the resiliency, redundancy, and representation for 
the species and thus were not considered as contributing to overall 
species viability.

                                             Table 9--Lesser Virgin Islands Skink Current Resiliency Summary
  [Numbers in parentheses are metric scores (see table 1), summed to provide overall resiliency. NA = not applicable, as likely extirpated and unknown
                                                          populations do not have resiliency.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Population                Habitat  protection      Predator pressure    Risk from storm surge          Status               Resiliency
--------------------------------------------------------------------------------------------------------------------------------------------------------
USVI
    Capella Island.................  High (1)..............  No impact (1).........  Low (0)..............  Unknown..............  NA
    Buck Island....................  High (1)..............  No impact (1).........  Low (0)..............  Unknown..............  NA
    Hans Lollik....................  Low (-1)..............  Low (0)...............  Low (0)..............  Extant...............  Low (-1)
    St. Thomas.....................  Moderate (0)..........  High (-1).............  Low (0)..............  Likely extirpated....  NA
BVI
    Little Thatch Island...........  Low (-1)..............  Low (0)...............  Low (0)..............  Unknown..............  NA
    Fallen Jerusalem...............  High (1)..............  Unknown...............  Low (0)..............  Unknown..............  NA

[[Page 103955]]

 
    Salt Island....................  Moderate (0)..........  Low (0)...............  Low (0)..............  Unknown..............  NA
    Round Rock Island..............  High (1)..............  Unknown...............  High (-1)............  Unknown..............  NA
    Ginger Island..................  Low (-1)..............  Unknown...............  Low (0)..............  Unknown..............  NA
    Guana Island...................  Low (-1)..............  Low (0)...............  Low (0)..............  Extant...............  Low (-1)
    Necker Island..................  Low (-1)..............  Low (0)...............  Low (0)..............  Likely extirpated....  NA
    Great Camanoe Island...........  Moderate (0)..........  Low (0)...............  Low (0)..............  Likely extirpated....  NA
    Mosquito Island................  Low (-1)..............  No impact (1).........  Low (0)..............  Extant...............  Moderate (0)
    Virgin Gorda...................  Moderate (0)..........  High (-1).............  Low (0)..............  Extant...............  Low (-1)
    Tortola........................  Moderate (0)..........  High (-1).............  Low (0)..............  Extant...............  Low (-1)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Currently, the species is considered extant on 5 of the 15 islands: 
1 in USVI (Hans Lollik) and 4 in BVI (Guana, Mosquito, Virgin Gorda, 
and Tortola) (table 9). Of the five, four have low resiliency, and one 
has moderate resiliency. Hans Lollik, the one extant population in the 
USVI, currently has low resiliency due to lack of habitat protection 
(privately owned) and predator pressure (rats present). In the BVI, one 
population is currently moderate, and three are low resiliency. There 
are mixed levels of habitat protection for the islands in the BVI; 
thus, development pressure is a risk to the species. In addition, each 
island has variable impacts from nonnative predators, and the two 
larger islands (Tortola and Virgin Gorda) have mongooses present. All 
islands have low impacts from storm surge due to the average height of 
these islands all being above 60 m (197 ft).
    Together, the extirpated and low-resiliency populations represent 
94 percent of the range of the Lesser Virgin Islands skink. Given the 
reduction in historical range, the species' redundancy and 
representation (adaptive capacity) have been greatly reduced from 
historical condition. Current redundancy, or distribution of 
populations with sufficient resiliency to withstand catastrophic 
events, is very low for this species as there is only one moderate-
resiliency population remaining. Given the limited range, any 
catastrophic event would likely negatively impact all existing 
populations, thus the species is unlikely to withstand catastrophic 
events.
    As part of the SSA report, we also developed future-condition 
scenarios to capture the range of uncertainties regarding future 
threats and the projected responses by the Lesser Virgin Islands skink. 
Our scenarios assumed nonnative predators are the main risk to 
populations which would cause reduced resiliency (note: it is highly 
unlikely that mongooses would ever be introduced). Because we 
determined that the current condition of the Lesser Virgin Islands 
skink is consistent with the Act's definition of an endangered species 
(see Determination of Status--Lesser Virgin Islands Skink, below), we 
are not presenting the results of the future scenarios in this proposed 
rule. Please refer to the SSA report (Service 2023, pp. 108-117) for 
the full analysis of future scenarios.

Virgin Islands Bronze Skink

    Virgin Islands bronze skink was historically known to occur on nine 
islands within the USVI and BVI. Four populations, making up 
approximately 96 percent of the species' historical range, are 
considered likely extirpated, including St. Thomas, the largest island 
in the USVI, and three islands in BVI (Little Tobago Island, Norman 
Island, and Peter Island). Currently, three of the nine islands are 
extant, all within the USVI (Buck Island, Turtledove Cay, and Water 
Island); there are no known extant populations occurring in BVI. The 
status of two populations (Capella Island and Salt Island) are 
currently unknown, primarily because recent surveys have not been 
conducted and very little information is known about these islands. 
Thus, we assumed that these two populations do not contribute to the 
resiliency, redundancy, and representation for the species and thus 
were not considered as contributing to overall species viability.

                                            Table 10--Virgin Islands Bronze Skink Current Resiliency Summary
  [Numbers in parentheses are metric scores (see table 1), summed to provide overall resiliency. NA = not applicable, as likely extirpated and unknown
                                                          populations do not have resiliency.]
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Population                Habitat protection       Predator pressure    Risk from storm surge          Status               Resiliency
--------------------------------------------------------------------------------------------------------------------------------------------------------
USVI
    Buck Island....................  High (1)..............  No impact (1).........  Low (0)..............  Extant...............  High (2)
    Capella Island.................  High (1)..............  No impact (1).........  Low (0)..............  Unknown..............  NA
    Turtledove Cay.................  High (1)..............  No impact (1).........  Low (0)..............  Extant...............  High (2)
    Water Island...................  Low (-1)..............  Low (0)...............  Low (0)..............  Extant...............  Low (-1)
    St. Thomas.....................  High (1)..............  High (-1).............  Low (0)..............  Likely extirpated....  NA
BVI
    Little Tobago Island...........  High (1)..............  Low (0)...............  Low (0)..............  Likely extirpated....  NA
    Salt Island....................  Moderate (0)..........  Low (0)...............  Low (0)..............  Unknown..............  NA
    Norman Island..................  Low (-1)..............  Low (0)...............  Low (0)..............  Likely extirpated....  NA
    Peter Island...................  Low (-1)..............  Low (0)...............  Low (0)..............  Likely extirpated....  NA
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 103956]]

    Of the three extant populations, two were assessed to have high 
resiliency while one was assessed to have low resiliency (table 
10).Water Island, the largest island (489 ac (198 ha)) with an extant 
population, is currently occupied by nonnative predators (rats) and 
privately owned, and therefore has low resiliency. Buck Island and 
Turtledove Cay have high resiliency due to high levels of habitat 
protection and no current predator pressure, as nonnative predators 
were eradicated previously, and the islands' elevations are not at risk 
from storm surge. Despite having two populations with high resiliency, 
the Virgin Islands bronze skink is vulnerable to catastrophic events 
such as the introduction of nonnative predators, primarily due to the 
extremely small size of the remaining extant islands (i.e., Buck Island 
and Turtledove Cay are 22 and 32 ac (9 and 13 ha) in size, 
respectively). Representation (and adaptive capacity) has been greatly 
reduced due to the loss of historical range and remaining islands 
making up 4 percent of the species' current range.
    As part of the SSA report, we also developed future-condition 
scenarios to capture the range of uncertainties regarding future 
threats and the projected responses by the Virgin Islands bronze skink. 
Our scenarios assumed nonnative predators and SLR are the main risks to 
populations in the future, which would cause reduced resiliency and 
eventual extirpation (note: it is highly unlikely that mongooses would 
ever be introduced). Because we determined that the current condition 
of the Virgin Islands bronze skink is consistent with the Act's 
definition of an endangered species (see Determination of Status--
Virgin Islands Bronze Skink, below), we are not presenting the results 
of the future scenarios in this proposed rule. Please refer to the SSA 
report (Service 2023, pp. 122-129) for the full analysis of future 
scenarios.

Greater St. Croix Skink

    The Greater St. Croix skink has been recorded from St. Croix and 
its satellite island Green Cay, both in the USVI; this is also presumed 
to be the provenance of several historical specimens with the locality 
data ``West Indies,'' suggesting that the skink was endemic to this 
large island and its satellite (Hedges and Conn 2012, p. 173). No more 
specific locality data are available, and the species was last recorded 
from St. Croix in the late 19th century, but this species has a well-
documented collection history, and it is consequently ``without 
dispute'' that the species historically occurred on the island (Hedges 
and Conn 2012, p. 174).
    Because the species has long been believed to be extirpated from 
St. Croix, not many targeted surveys to look for skinks on the island 
have occurred. Qualified researchers and wildlife agency staff have 
made several efforts to look for other herpetofauna on both St. Croix 
and Green Cay that would almost certainly document opportunistic 
encounters of any herp species, and since 2000, no known documentation 
of skinks exists (see appendix B-II of SSA report (Service 2023, pp. 
154-160)). Given what is known about the life history and habitat 
associations of Spondylurus skinks, it is reasonable to assume that 
skinks would have been detected given the extent of survey efforts in 
optimal habitats on St. Croix and Green Cay.
    Skinks that once occurred on St. Croix faced a primary threat from 
the introduced mongoose, a predator that has been implicated in the 
extinction of the Greater St. Croix skink (Hedges and Conn 2012, p. 
174; Hedges 2013, p. 4). The invasive predator was introduced as a 
biological control of rats in sugar cane fields in the late nineteenth 
century, immediately resulting in a mass extinction of skinks and other 
reptiles (Hedges and Conn 2012, p. 4). The ground-dwelling and diurnal 
habits of skinks have made them particularly susceptible to mongoose 
predation.
    Based on the best scientific and commercial information available, 
it is highly unlikely that an individual of Greater St. Croix skink 
could be extant but undetected; therefore, we presume that the species 
is likely extinct.

Lesser St. Croix Skink

    The Lesser St. Croix skink is believed to be endemic to the large 
island of St. Croix in the USVI, which has an area of 230 km\2\ (Hedges 
and Conn 2012, p. 69). The only known specimen from 1875 was reported 
with no precise locality data (Hedges and Conn 2012, p. 68). The 
introduction of mongooses to this island in the late 19th century, and 
the seeming disappearance of the Greater St. Croix skink at the same 
time, suggests that the Lesser St. Croix skink is probably now extinct 
(Hedges and Conn 2012, p. 69).
    Because the species has long been believed to be extirpated from 
St. Croix, not many targeted surveys to look for skinks on the island 
have occurred. Qualified researchers and wildlife agency staff have 
made several efforts to look for other herpetofauna that would almost 
certainly document opportunistic encounters of any herp species (see 
appendix B-III of SSA report (Service 2023, pp. 162-168)). Given what 
is known about the life history and habitat associations of Capitellum 
skinks, it is reasonable to assume that skinks would have been detected 
given the extent of survey efforts in optimal habitats on St. Croix.
    Skinks that once occurred on St. Croix faced threats from habitat 
loss and predation from the introduced mongoose, a predator that has 
been implicated in the extinction of the Lesser St. Croix skink (Hedges 
and Conn 2012, p. 69; Hedges 2013, p. 1) and other lizards. For 
example, the mongoose is also partly implicated for the extirpation of 
the endangered St. Croix ground lizard, last seen on the main island of 
St. Croix in 1964 (Service 1984, entire). The mongoose was introduced 
as a biological control of rats in sugar cane fields in the late 
nineteenth century, immediately resulting in a mass extinction of 
skinks and other reptiles (Hedges and Conn 2012, p. 4). The ground-
dwelling and diurnal habits of skinks have made them particularly 
susceptible to predation by mongooses and cats.
    Based on the best scientific and commercial information available, 
it is highly unlikely that an individual of Lesser St. Croix skink 
could be extant but undetected; therefore, we presume that the species 
is likely extinct.

Determination of Status for Eight Caribbean Skink Species

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of an endangered species or a 
threatened species. The Act defines an ``endangered species'' as a 
species in danger of extinction throughout all or a significant portion 
of its range and a ``threatened species'' as a species likely to become 
an endangered species within the foreseeable future throughout all or a 
significant portion of its range. The Act requires that we determine 
whether a species meets the definition of an endangered species or a 
threatened species because of any of the following factors: (A) The 
present or threatened destruction, modification, or curtailment of its 
habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence.

[[Page 103957]]

Status Throughout All of Its Range--Puerto Rican Skink

    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we assessed the status of the Puerto Rican skink to determine 
if it meets the Act's definition of an endangered species. The Puerto 
Rican skink was historically known from three island populations and 
six populations on the main island of Puerto Rico. Four historical 
populations, approximately 35 percent of the species' historical range, 
are considered likely extirpated, including two of the smaller islands 
within the range.
    Of the five extant populations, one of the smaller islands, 
Desecheo, is currently occupied and has high resiliency based on 
habitat metrics, including no predators, and the island is protected as 
an NWR. Predators were previously present on Desecheo and success of 
eradication efforts was confirmed in 2017. Of note, the last detection 
record for the Puerto Rican skink on Desecheo Island was in 2016, 
although there were no surveys conducted on the island during 2021-2023 
survey efforts. This population represents 0.19 percent of the extant 
range.
    The remaining four populations occur on the main island of Puerto 
Rico; two populations currently have moderate resiliency, and two have 
low resiliency. Habitat for all populations is generally located at 
elevations that are not at risk of storm surge or sea level rise. 
Development (Factor A) is a risk to all populations. Because the main 
island of Puerto Rico is occupied by nonnative predators (Factor C) 
including mongooses, rats, cats, and dogs, the influence of predator 
pressure on population resiliency is always present and therefore 
considered high risk to skinks.
    The five extant populations are geographically isolated at 
considerable distance from one another, and, therefore, it will be 
difficult for a higher resiliency population to supplement or rescue 
another population affected by potential catastrophic events. Together, 
the extirpated and low-resiliency populations represent 75 percent of 
the range. Given the reduction in historical range, the species' 
redundancy has been reduced from historical condition, and 
representation (and adaptive capacity) has also been reduced. The 
current resiliency, redundancy, and representation indicate that the 
magnitude and scale of threats are currently impacting the Puerto Rican 
skink such that it meets the Act's definition of an endangered 
species.Thus, after assessing the best available information, we 
determine that Puerto Rican skink is in danger of extinction throughout 
all of its range. Because the threats are currently impacting the 
species such that it is in danger of extinction currently throughout 
all of its range, it does not meet the Act's definition of a threatened 
species.

Status Throughout a Significant Portion of Its Range--Puerto Rican 
Skink

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
within the foreseeable future throughout all or a significant portion 
of its range. We have determined that the Puerto Rican skink is in 
danger of extinction throughout all of its range and accordingly did 
not undertake an analysis of any significant portion of its range. 
Because the Puerto Rican skink warrants listing as endangered 
throughout all of its range, our determination does not conflict with 
the decision in Center for Biological Diversity v. Everson, 435 F. 
Supp. 3d 69 (D.D.C. 2020), because that decision related to significant 
portion of the range analyses for species that warrant listing as 
threatened, not endangered, throughout all of their range.

Determination of Status--Puerto Rican Skink

    Based on the best scientific and commercial data available, we 
determine that the Puerto Rican skink meets the Act's definition of an 
endangered species. Therefore, we propose to list the Puerto Rican 
skink as an endangered species in accordance with sections 3(6) and 
4(a)(1) of the Act.

Status Throughout All of Its Range--Mona Skink

    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the section 4(a)(1) factors, we 
evaluated the status of the Mona skink to determine if it meets the 
Act's definition of an endangered species. The Mona skink is 
historically and currently known only from Mona Island, a 13,838-ac 
(5,600-ha) island off the west coast of Puerto Rico. The entire island 
is a designated nature preserve protected and managed by the PRDNER. 
The Mona skink has been consistently detected on the island over time 
with the earliest known detection in 1894 to more recent detections in 
2021. The species continues to be observed on Mona Island, indicating 
that the population has maintained a level of resiliency to withstand 
stochastic events over time.
    The primary threat driving the species' viability is nonnative 
predators (Factor C). Mona Island is currently occupied by nonnative 
predators (cats and rats) and also goats and pigs. There are no 
mongooses or dog predators on the island. Given the larger size of the 
island and that mongooses are not present, predator pressure was 
assessed as low for the species. Low does not mean there is no predator 
pressure but a lower level of predator pressure from cats and rats. 
Mona Island has a maximum elevation of over 296 ft (90 m) and, 
therefore, most of the island is not susceptible to impacts from storm 
surge or sea level rise (Factor E) like other low-lying islands. Mona 
Island has high habitat protection given it is protected and managed by 
PRDNER, and therefore there are no current impacts from development 
pressure (Factor A).
    The current resiliency of the one Mona skink population is 
moderate. Though the species is known only from Mona Island and likely 
consists of a single population, there are multiple habitat patches 
occupied across the island and the species occupies interior as well as 
coastal areas of the island. Although the species is impacted by some 
threats across the range, the Mona skink exhibits sufficient 
resiliency, redundancy, and representation to support the species' 
viability. Overall, no current threat is acting at an extent or 
severity such that the species is at risk of extinction throughout all 
of its range. Thus, after assessing the best available information, we 
conclude that the Mona skink is not in danger of extinction throughout 
all of its range. Therefore, we proceed with determining whether the 
Mona skink is likely to become endangered within the foreseeable future 
throughout all of its range.
    In considering future threats to the species, we examined habitat 
destruction and modification from development risk (Factor A); 
nonnative predators (Factor C); climate change, specifically SLR 
(Factor E); and increases in intensity, frequency, and duration of 
hurricane activity (Factor E) out to the end of the century, or 2100. 
For the Mona skink, nonnative predators are the primary driver to the 
species' viability in the future. There is a chance of introduction of 
additional nonnative predators from tourism, and thus increased 
predator pressure to the Mona skink in the future. However, ongoing and 
future funded eradication efforts of nonnative predators is likely to 
occur. Given the larger size of the

[[Page 103958]]

island, and that mongooses are not likely to be introduced, predator 
pressure was assessed as low in the future for the species. Nonnative 
predator introductions would be expected to reduce skink numbers on the 
island, but the island is large and includes a diversity of habitats 
and patches: therefore, predation risk is not likely to eliminate the 
known population, nor do we expect it to reduce to low-resiliency 
condition in the future. Impacts from climate change in the future were 
also assessed as low for similar reasons as current impacts because 
most of the island is not susceptible to impacts from SLR or increased 
hurricane activity. Further, impacts of development pressure to the 
species are low as Mona Island has high habitat protection given it is 
protected and managed by PRDNER.
    The projected future resiliency of skinks on Mona Island is 
assessed as moderate, given the future level of threats to the species. 
The future range of the Mona skink is limited to one island; however, 
it is still expected to have moderate resiliency to withstand 
stochastic events. Although the species is impacted by some level of 
threats across the range, the Mona skink exhibits sufficient 
resiliency, redundancy, and representation to support the species' 
future viability. Overall, no projected future threat is acting at an 
extent or severity such that the species is at risk of extinction 
throughout all of its range within the foreseeable future. Thus, after 
assessing the best available information, we conclude that the Mona 
skink is not likely to become endangered within the foreseeable future 
throughout all of its range.

Status Throughout a Significant Portion of Its Range--Mona Skink

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
within the foreseeable future throughout all or a significant portion 
of its range. Having determined that the Mona skink is not in danger of 
extinction or likely to become so within the foreseeable future 
throughout all of its range, we now consider whether it may be in 
danger of extinction or likely to become so within the foreseeable 
future in a significant portion of its range--that is, whether there is 
any portion of the species' range for which it is true that both (1) 
the portion is significant; and (2) the species is in danger of 
extinction now or likely to become so within the foreseeable future in 
that portion. Depending on the case, it might be more efficient for us 
to address the ``significance'' question or the ``status'' question 
first. We can choose to address either question first. Regardless of 
which question we address first, if we reach a negative answer with 
respect to the first question that we address, we do not need to 
evaluate the other question for that portion of the species' range.
    In undertaking this analysis for the Mona skink, we chose to 
address the status question first. We began by identifying portions of 
the range where the biological status of the species may be different 
from its biological status elsewhere in its range. For this purpose, we 
considered information pertaining to the geographic distribution of (a) 
individuals of the species, (b) the threats that the species faces, and 
(c) the resiliency condition of populations.
    We evaluated the range of the Mona skink to determine if the 
species is in danger of extinction now or likely to become so within 
the foreseeable future in any portion of its range. The Mona skink is a 
narrow endemic that functions as a single, contiguous population and 
occurs on one 13,838-ac (5,600-ha) island (Mona Island). Thus, there is 
no biologically meaningful way to break this limited range into 
portions, and the threats that the species faces affect the species 
comparably throughout its entire range. As a result, there are no 
portions of the species' range where the species has a different 
biological status from its rangewide biological status. Therefore, we 
conclude that there are no portions of the species' range that warrant 
further consideration, and the species is not in danger of extinction 
or likely to become so within the foreseeable future in any significant 
portion of its range. This does not conflict with the courts' holdings 
in Desert Survivors v. U.S. Department of the Interior, 321 F. Supp. 3d 
1011, 1070-74 (N.D. Cal. 2018) and Center for Biological Diversity v. 
Jewell, 248 F. Supp. 3d. 946, 959 (D. Ariz. 2017) because, in reaching 
this conclusion, we did not apply the aspects of the Final Policy on 
Interpretation of the Phrase ``Significant Portion of Its Range'' in 
the Endangered Species Act's Definitions of ``Endangered Species'' and 
``Threatened Species'' (79 FR 37578; July 1, 2014), including the 
definition of ``significant'' that those court decisions held to be 
invalid.

Determination of Status--Mona Skink

    Based on the best scientific and commercial data available, we 
determine that the Mona skink does not meet the Act's definition of an 
endangered species or a threatened species in accordance with sections 
3(6) and 3(20) of the Act. Therefore, we find that listing the Mona 
skink is not warranted at this time.

Status Throughout All of Its Range--Culebra Skink

    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we evaluated the status of the Culebra skink to determine if 
it meets the Act's definition of an endangered species. The Culebra 
skink historically occupied six islands across the species' known 
range. Currently, it occupies five islands, including Culebra and four 
small cays surrounding Culebra. The skink is likely extirpated from 
Isla Culebrita, as it has not been observed there since 1936. Of the 
five currently known extant populations, the smaller cays have no 
predator pressure and are all protected from development. However, 
because each cay has low elevation and is small in size, it is at high 
risk of impacts from storm surge (Factor E). Culebra currently has 
predators (Factor C) present (cats, rats) and a mix of land uses, with 
expanding developed lands (Factor A) and some protected lands.
    The Culebra skink currently has five extant populations with 
moderate resiliency. The current number and distribution of these 
sufficiently resilient populations enables the species to withstand 
both stochastic and catastrophic events. While the range is relatively 
small and many of the cays are small, the species currently has 
substantial genetic representation in the form of separate islands.The 
Culebra skink currently exhibits sufficient resiliency, redundancy, and 
representation to support viability. Overall, no current threat is 
acting at an extent or severity such that the species is at risk of 
extinction throughout all of its range. Thus, after assessing the best 
available information, we conclude that the Culebra skink is not in 
danger of extinction throughout all of its range and does not meet the 
definition of an endangered species.
    In the future, sea level rise (Factor E) and storm impacts (Factor 
E) will be realized, along with increased development pressure (Factor 
A) on Culebra and increased predator risk (Factor C) across the range. 
When predators reach the small cays, skink extirpation is imminent. 
Further, three of the four cays have low elevations such that storm 
surge risk and sea level rise will result in extirpation of the 
population on one cay by 2070, and the remaining cays' populations by 
2100. Given the future projections, the

[[Page 103959]]

number and distribution of skink populations impacted in the future 
will affect the species' ability to withstand both stochastic and 
catastrophic events. Therefore, the Culebra skink is projected not to 
have sufficient resiliency, redundancy, and representation to support 
the species' viability within the foreseeable future. Thus, after 
assessing the best available information, we conclude that the Culebra 
skink is likely to become in danger of extinction throughout all of its 
range within the foreseeable future.

Status Throughout a Significant Portion of Its Range--Culebra Skink

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
in the foreseeable future throughout all or a significant portion of 
its range. The court in Center for Biological Diversity v. Everson, 435 
F. Supp. 3d 69 (D.D.C. 2020) (Everson), vacated the provision of the 
Final Policy on Interpretation of the Phrase ``Significant Portion of 
Its Range'' in the Endangered Species Act's Definitions of ``Endangered 
Species'' and ``Threatened Species'' (hereafter ``Final Policy''; 79 FR 
37578, July 1, 2014) that provided if the Services determine that a 
species is threatened throughout all of its range, the Services will 
not analyze whether the species is endangered in a significant portion 
of its range.
    Therefore, we proceed to evaluating whether the species is 
endangered in a significant portion of its range--that is, whether 
there is any portion of the species' range for which both (1) the 
portion is significant; and (2) the species is in danger of extinction 
in that portion. Depending on the case, it might be more efficient for 
us to address the ``significance'' question or the ``status'' question 
first. We can choose to address either question first. Regardless of 
which question we address first, if we reach a negative answer with 
respect to the first question that we address, we do not need to 
evaluate the other question for that portion of the species' range.
    Following the court's holding in Everson, we now consider whether 
the species is in danger of extinction (i.e., endangered) in a 
significant portion of its range. In undertaking this analysis for 
Culebra skink, we choose to address the status question first.
    We evaluated the range of the Culebra skink to determine if the 
species is in danger of extinction now in any portion of its range. The 
range of a species can theoretically be divided into portions in an 
infinite number of ways. We focused our analysis on portions of the 
species' range that may meet the definition of an endangered species. 
For the Culebra skink, we considered whether the threats or their 
effects on the species are greater in any biologically meaningful 
portion of the species' range than in other portions such that the 
species is in danger of extinction now in that portion.
    The statutory difference between an endangered species and a 
threatened species is the timeframe in which the species becomes in 
danger of extinction; an endangered species is in danger of extinction 
now while a threatened species is not in danger of extinction now but 
is likely to become so within the foreseeable future. Thus, we 
considered the time horizon for the threats that are driving the 
Culebra skink to warrant listing as a threatened species throughout all 
of its range. We then considered whether these threats or their effects 
are occurring in any portion of the species' range such that the 
species is in danger of extinction now in that portion of its range. We 
examined the following threats: habitat destruction or modification 
through development risk, nonnative predators, and storm surge, 
including cumulative effects. Current population resiliency is moderate 
across the Culebra skink's range. The small cays currently occupied by 
skinks are small (<10 ac (4 ha)) but are not currently occupied by any 
nonnative predators and are protected from development. Much of the 
land on each cay is low elevation (i.e., less than 33 ft (10 m)), 
making them susceptible to storm surge. The island of Culebra is 
inhabited by people and there is development throughout the island, 
except in areas that are protected, primarily the Culebra NWR in the 
north. Because of the development, there are many nonnative predators 
including cats and rats, but no mongooses are currently found on the 
island. The island of Culebra has a higher average elevation (~646 ft 
(197 m)) than the smaller cays and is less susceptible to storm surge 
risk currently. Despite differences in impacts of threats, all 
populations currently have moderate resiliency and have sufficient 
redundancy such that no portions would meet the Act's definition of an 
endangered species.
    The best scientific and commercial data available indicate that the 
time horizon on which those threats to the species and the species' 
response to those threats are likely to occur is the foreseeable 
future. In addition, the best scientific and commercial data available 
do not indicate that any of the threats to the species and the species' 
response to those threats are more immediate in any portions of the 
species' range. Therefore, we determine that the Culebra skink is not 
in danger of extinction now in any portion of its range, but that the 
species is likely to become in danger of extinction within the 
foreseeable future throughout all of its range. This does not conflict 
with the courts' holdings in Desert Survivors v. U.S. Department of the 
Interior, 321 F. Supp. 3d 1011, 1070-74 (N.D. Cal. 2018) and Center for 
Biological Diversity v. Jewell, 248 F. Supp. 3d 946, 959 (D. Ariz. 
2017) because, in reaching this conclusion, we did not apply the 
aspects of the Final Policy, including the definition of 
``significant'' that those court decisions held to be invalid.

Determination of Status--Culebra Skink

    Based on the best scientific and commercial data available, we 
determine that the Culebra skink meets the Act's definition of a 
threatened species. Therefore, we propose to list the Culebra skink as 
a threatened species in accordance with sections 3(20) and 4(a)(1) of 
the Act.

Status Throughout All of Its Range--Greater Virgin Islands Skink

    When evaluating the possibility of extinction, we attempted to 
minimize the possibility of either (1) prematurely determining that the 
species is extinct where individuals exist but remain undetected, or 
(2) assuming the species is extant when extinction has already 
occurred. Our determinations of whether the best scientific and 
commercial data available indicate that a species is extinct included 
an analysis of the following criteria: detectability of the species, 
adequacy of survey efforts, and time since last detection. All three 
criteria require taking into account applicable aspects of the species' 
life history. Other lines of evidence may also support the 
determination and be included in our analysis.
    In conducting our analyses of whether the Greater Virgin Islands 
skink is extinct, we considered and thoroughly evaluated the best 
scientific and commercial data available. We reviewed the information 
available in our files and other available published and unpublished 
information. These evaluations include information from recognized 
experts, Federal and State governments, academic institutions, and 
private entities.
    The Greater Virgin Islands skink was a small lizard known from six 
specimens collected in the 1800s, with the most recent observation from 
1877. The skink's small size, cryptic coloration, and secretive 
behavior could prevent detection; however, considerable effort to 
observe other

[[Page 103960]]

herpetofauna by qualified researchers has been invested across several 
decades on both St. Thomas and St. John, where the species once 
occurred. These multiple survey efforts, while not targeted at skinks, 
did overlap with potential skink habitat, and would most likely have 
encountered skinks if they were still extant. The loss of the Greater 
Virgin Islands skink can be attributed to predation by the mongoose. No 
skinks have been observed on St. Thomas or St. John for over a century. 
Based on the best scientific and commercial information available, it 
is highly unlikely that an individual could be extant but undetected; 
therefore, we conclude that the Greater Virgin Islands skink is 
extinct. A detailed discussion of the basis for this finding can be 
found in appendix B-I of the SSA report (Service 2023, pp. 146-154) and 
other supporting documents (see ADDRESSES, above).

Determination of Status--Greater Virgin Islands Skink

    Based on the best scientific and commercial data available, we 
determine that the Greater Virgin Islands skink is extinct and is 
therefore not warranted for listing at this time.

Status Throughout All of Its Range--Lesser Virgin Island Skink

    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we assessed the status of the Lesser Virgin Islands skink to 
determine if it meets the Act's definition of an endangered species. 
The Lesser Virgin Islands skink was historically known to occur on 15 
islands within the USVI and BVI. Three historically occupied islands, 
making up approximately 43 percent of the species' historical range, 
are considered likely extirpated, including St. Thomas, the largest 
island in the USVI. The status of seven populations (Capella Island, 
Buck Island, Little Thatch Island, Fallen Jerusalem, Salt Island, Round 
Rock Island, and Ginger Island) is currently unknown, primarily because 
recent surveys have not been conducted and very little information is 
known about these islands. The best available science indicates that 
likely threats exist such that these seven populations do not 
contribute to the resiliency, redundancy, and representation for the 
species, and thus were not considered as contributing to overall 
species viability.
    Currently, the Lesser Virgin Islands skink is considered extant on 
5 of the 15 islands: 1 in USVI (Hans Lollik) and 4 in BVI (Guana, 
Mosquito, Virgin Gorda and Tortola). Of the five, four have low 
resiliency and one has moderate resiliency. Hans Lollik, the one extant 
population in the USVI, currently has low resiliency due to a lack of 
habitat protection (privately owned land) (Factor A) and having 
predator pressure (rats present) (Factor C). In the BVI, one population 
is currently moderate, and three are low resiliency. The islands in the 
BVI provide mixed levels of habitat protection; thus, development 
pressure is a risk. In addition, each island has variable impacts from 
nonnative predators, and the two larger islands (Tortola and Virgin 
Gorda) have mongooses present. All islands have low impacts from storm 
surge due to the average elevation of these islands.
    Together, the extirpated and low-resiliency populations represent 
94 percent of the range. Given the reduction in historical range, the 
species' redundancy has been reduced from historical condition, and 
representation (and adaptive capacity) has also been reduced. The 
current resiliency, redundancy, and representation indicate that the 
magnitude and scale of threats are currently impacting the Lesser 
Virgin Islands skink such that it meets the Act's definition of an 
endangered species. Thus, after assessing the best available 
information, we determine that the Lesser Virgin Islands skink is in 
danger of extinction throughout all of its range. Because the threats 
are currently impacting the species such that it is in danger of 
extinction currently throughout all of its range, it does not meet the 
Act's definition of a threatened species.

Status Throughout a Significant Portion of Its Range--Lesser Virgin 
Islands Skink

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
within the foreseeable future throughout all or a significant portion 
of its range. We have determined that the Lesser Virgin Islands skink 
is in danger of extinction throughout all of its range and accordingly 
did not undertake an analysis of any significant portion of its range. 
Because the Lesser Virgin Islands skink warrants listing as endangered 
throughout all of its range, our determination does not conflict with 
the decision in Center for Biological Diversity v. Everson, 435 F. 
Supp. 3d 69 (D.D.C. 2020), because that decision related to significant 
portion of the range analyses for species that warrant listing as 
threatened, not endangered, throughout all of their range.

Determination of Status--Lesser Virgin Islands Skink

    Based on the best scientific and commercial data available, we 
determine that the Lesser Virgin Islands skink meets the Act's 
definition of an endangered species. Therefore, we propose to list the 
Lesser Virgin Islands skink as an endangered species in accordance with 
sections 3(6) and 4(a)(1) of the Act.

Status Throughout All of Its Range--Virgin Islands Bronze Skink

    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we assessed the status of the Virgin Islands bronze skink to 
determine if it meets the Act's definition of an endangered species. 
The Virgin Islands bronze skink was historically known to occur on nine 
islands within the USVI and BVI. Four populations, making up 
approximately 96 percent of the species' historical range, are 
considered likely extirpated, including St. Thomas, the largest island 
in the USVI. Currently, three of the nine islands are extant, all 
within the USVI; there are no known extant populations occurring in 
BVI. The status of two populations (Capella Island and Salt Island) are 
currently unknown, primarily because recent surveys have not been 
conducted and very little information is known about these islands.
    Of the three extant populations, two were assessed to have high 
resiliency while one was assessed to have low resiliency.Water Island, 
the largest island (489 ac (198 ha)) with an extant population, is 
currently occupied by nonnative predators (rats) and privately owned, 
and therefore has low resiliency. Buck Island and Turtledove Cay have 
high resiliency due to high levels of habitat protection and no current 
predator pressure, as nonnative predators were eradicated previously. 
Despite having two populations with high resiliency, the Virgin Islands 
bronze skink is vulnerable to catastrophic events, primarily due to the 
small size of the remaining extant islands (i.e., Buck Island and 
Turtledove Cay being 22 and 32 ac (9 and 13 ha) in size, respectively). 
Representation (and adaptive capacity) has been greatly reduced due to 
the loss of historical range and remaining islands making up 4 percent 
of the current range.
    Given the current resiliency, redundancy, and representation of the 
Virgin Islands bronze skink, the

[[Page 103961]]

magnitude and scale of threats are impacting the species such that it 
meets the Act's definition of an endangered species.Thus, after 
assessing the best available information, we determine that the Virgin 
Islands bronze skink is in danger of extinction throughout all of its 
range. Because the threats are currently impacting the species such 
that it is in danger of extinction currently throughout all of its 
range, it does not meet the Act's definition of a threatened species.

Status Throughout a Significant Portion of Its Range--Virgin Islands 
Bronze Skink

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
within the foreseeable future throughout all or a significant portion 
of its range. We have determined that the Virgin Islands bronze skink 
is in danger of extinction throughout all of its range and accordingly 
did not undertake an analysis of any significant portion of its range. 
Because the Virgin Islands bronze skink warrants listing as endangered 
throughout all of its range, our determination does not conflict with 
the decision in Center for Biological Diversity v. Everson, 435 F. 
Supp. 3d 69 (D.D.C. 2020), because that decision related to significant 
portion of the range analyses for species that warrant listing as 
threatened, not endangered, throughout all of their range.

Determination of Status--Virgin Islands Bronze Skink

    Based on the best scientific and commercial data available, we 
determine that the Virgin Islands bronze skink meets the Act's 
definition of an endangered species. Therefore, we propose to list the 
Virgin Islands bronze skink as an endangered species in accordance with 
sections 3(6) and 4(a)(1) of the Act.

Status Throughout All of Its Range--Greater St. Croix Skink

    When evaluating the possibility of extinction, we attempted to 
minimize the possibility of either (1) prematurely determining that the 
species is extinct where individuals exist but remain undetected, or 
(2) assuming the species is extant when extinction has already 
occurred. Our determinations of whether the best scientific and 
commercial data available indicate that a species is extinct included 
an analysis of the following criteria: detectability of the species, 
adequacy of survey efforts, and time since last detection. All three 
criteria require taking into account applicable aspects of the species' 
life history. Other lines of evidence may also support the 
determination and be included in our analysis.
    In conducting our analyses of whether the Greater St. Croix skink 
is extinct, we considered and thoroughly evaluated the best scientific 
and commercial data available. We reviewed the information available in 
our files, and other available published and unpublished information. 
These evaluations include information from recognized experts, Federal 
and State governments, academic institutions, and private entities.
    The Greater St. Croix skink was a small lizard known to occur in 
St. Croix and Green Cay. The skink's small size, cryptic coloration, 
and secretive behavior could prevent detection; however, considerable 
effort to observe other herpetofauna by qualified researchers has been 
invested across several decades on St. Croix and Green Cay, where the 
species once occurred. These multiple survey efforts, while not 
targeted at skinks, did overlap with potential skink habitat, and would 
most likely have encountered skinks if they were still extant. The loss 
of the Greater St. Croix skink can be attributed to predation by the 
mongoose. No skinks have been observed on St. Croix for over a century, 
and none have been observed on Green Cay for nearly a quarter of a 
century. Based on the best scientific and commercial information 
available, it is highly unlikely that an individual could be extant but 
undetected. Therefore, we conclude that the Greater St. Croix skink is 
extinct. A detailed discussion of the basis for this finding can be 
found in appendix B-II of the SSA report (Service 2023, pp. 154-162) 
and other supporting documents (see ADDRESSES, above).

Determination of Status--Greater St. Croix Skink

    Based on the best scientific and commercial data available, we 
determine that the Greater St. Croix skink is extinct and is therefore 
not warranted for listing at this time.

Status Throughout All of Its Range--Lesser St. Croix Skink

    When evaluating the possibility of extinction, we attempted to 
minimize the possibility of either (1) prematurely determining that the 
species is extinct where individuals exist but remain undetected, or 
(2) assuming the species is extant when extinction has already 
occurred. Our determinations of whether the best scientific and 
commercial data available indicate that a species is extinct included 
an analysis of the following criteria: detectability of the species, 
adequacy of survey efforts, and time since last detection. All three 
criteria require taking into account applicable aspects of the species' 
life history. Other lines of evidence may also support the 
determination and be included in our analysis.
    In conducting our analyses of whether the Lesser St. Croix skink is 
extinct, we considered and thoroughly evaluated the best scientific and 
commercial data available. We reviewed the information available in our 
files and other available published and unpublished information. These 
evaluations include information from recognized experts, Federal and 
State governments, academic institutions, and private entities.
    The Lesser St. Croix skink was a small lizard known from only one 
specimen collected in 1875. The skink's small size, cryptic coloration, 
and secretive behavior could lower detection probabilities; however, 
considerable effort to observe other herpetofauna by qualified 
researchers has been invested across several decades on St. Croix, 
where the species once occurred. These multiple survey efforts, while 
not targeted at skinks, did overlap with potential skink habitat, and 
would most likely have detected skinks if they were still extant. The 
loss of the Lesser St. Croix skink is mainly attributed to predation by 
the mongoose in addition to habitat loss. No skinks have been observed 
on St. Croix for over a century. Based on the best scientific and 
commercial information available, it is highly unlikely that an 
individual would be extant but undetected. Therefore, we conclude that 
the Lesser St. Croix skink is extinct. A detailed discussion of the 
basis for this finding can be found in appendix B-III of the SSA report 
(Service 2023, pp. 162-169) and other supporting documents (see 
ADDRESSES, above).

Determination of Status--Lesser St. Croix Skink

    Based on the best scientific and commercial data available, we 
determine that the Lesser St. Croix skink is extinct and is therefore 
not warranted for listing at this time.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened species under the Act include recognition as a listed 
species, planning and implementation of recovery actions, requirements 
for Federal protection, and prohibitions against certain practices. 
Recognition through listing results in public

[[Page 103962]]

awareness, and conservation by Federal, State, Tribal, and local 
agencies, private organizations, and individuals. The Act encourages 
cooperation with the States and other countries and calls for recovery 
actions to be carried out for listed species. The protection required 
by Federal agencies, including the Service, and the prohibitions 
against certain activities are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Section 4(f) of the Act calls for the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The goal of this process is to restore listed 
species to a point where they are secure, self-sustaining, and 
functioning components of their ecosystems.
    The recovery planning process begins with development of a recovery 
outline made available to the public soon after a final listing 
determination. The recovery outline guides the immediate implementation 
of urgent recovery actions while a recovery plan is being developed. 
Recovery teams (composed of species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) may be 
established to develop and implement recovery plans. The recovery 
planning process involves the identification of actions that are 
necessary to halt and reverse the species' decline by addressing the 
threats to its survival and recovery. The recovery plan identifies 
recovery criteria for review of when a species may be ready for 
reclassification from endangered to threatened (``downlisting'') or 
removal from protected status (``delisting''), and methods for 
monitoring recovery progress. Recovery plans also establish a framework 
for agencies to coordinate their recovery efforts and provide estimates 
of the cost of implementing recovery tasks. Revisions of the plan may 
be done to address continuing or new threats to the species, as new 
substantive information becomes available. The recovery outline, draft 
recovery plan, final recovery plan, and any revisions will be available 
on our website as they are completed (https://www.fws.gov/program/endangered-species) or from our Caribbean Ecological Services Field 
Office (see FOR FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    If these species are listed, funding for recovery actions will be 
available from a variety of sources, including Federal budgets, State 
programs, and cost-share grants for non-Federal landowners, the 
academic community, and nongovernmental organizations. In addition, 
pursuant to section 6 of the Act, the Commonwealth of Puerto Rico and 
Territory of the USVI would be eligible for Federal funds to implement 
management actions that promote the protection or recovery of the 
Puerto Rican skink, Culebra skink, Lesser Virgin Islands skink, and 
Virgin Islands bronze skink. Information on our grant programs that are 
available to aid species recovery can be found at: https://www.fws.gov/service/financial-assistance.
    Although the Puerto Rican skink, Culebra skink, Lesser Virgin 
Islands skink, and Virgin Islands bronze skink are only proposed for 
listing under the Act at this time, please let us know if you are 
interested in participating in recovery efforts for this species. 
Additionally, we invite you to submit any new information on these 
species whenever it becomes available and any information you may have 
for recovery planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7 of the Act is titled, ``Interagency Cooperation,'' and it 
mandates all Federal action agencies to use their existing authorities 
to further the conservation purposes of the Act and to ensure that 
their actions are not likely to jeopardize the continued existence of 
listed species or adversely modify critical habitat. Regulations 
implementing section 7 are codified at 50 CFR part 402.
    Section 7(a)(2) states that each Federal action agency shall, in 
consultation with the Secretary, ensure that any action they authorize, 
fund, or carry out is not likely to jeopardize the continued existence 
of a listed species or result in the destruction or adverse 
modification of designated critical habitat. Each Federal agency shall 
review its action at the earliest possible time to determine whether it 
may affect listed species or critical habitat. If a determination is 
made that the action may affect listed species or critical habitat, 
formal consultation is required (50 CFR 402.14(a)), unless the Service 
concurs in writing that the action is not likely to adversely affect 
listed species or critical habitat. At the end of a formal 
consultation, the Service issues a biological opinion, containing its 
determination of whether the Federal action is likely to result in 
jeopardy or adverse modification.
    In contrast, section 7(a)(4) of the Act requires Federal agencies 
to confer with the Service on any 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 critical 
habitat proposed to be designated for such species. Although the 
conference procedures are required only when an action is likely to 
result in jeopardy or adverse modification, action agencies may 
voluntarily confer with the Service on actions that may affect species 
proposed for listing or critical habitat proposed to be designated. In 
the event that the subject species are listed, or the relevant critical 
habitats are designated, a conference opinion may be adopted as a 
biological opinion and serve as compliance with section 7(a)(2).
    Examples of discretionary actions for the Puerto Rican skink, 
Culebra skink, Lesser Virgin Islands skink, and Virgin Islands bronze 
skink that may be subject to conference and consultation procedures 
under section 7 of the Act are management of Federal lands administered 
by the National Park Service and the U.S. Forest Service, as well as 
actions 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 actions funded by Federal agencies such as 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 agency--do not require section 7 consultation. 
Federal agencies should coordinate with the local Service Field Office 
(see FOR FURTHER INFORMATION CONTACT) with any specific questions on 
section 7 consultation and conference requirements.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply

[[Page 103963]]

to endangered wildlife. The prohibitions of section 9(a)(1) of the Act, 
codified at 50 CFR 17.21, make it illegal for any person subject to the 
jurisdiction of the United States to commit, to attempt to commit, to 
solicit another to commit or to cause to be committed any of the 
following acts with regard to endangered wildlife: (1) import into, or 
export from, the United States; (2) take (which includes harass, harm, 
pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to 
attempt to engage in any such conduct) within the United States, within 
the territorial sea of the United States, or on the high seas; (3) 
possess, sell, deliver, carry, transport, or ship, by any means 
whatsoever, any such wildlife that has been taken illegally; (4) 
deliver, receive, carry, transport, or ship in interstate or foreign 
commerce, by any means whatsoever and in the course of commercial 
activity; or (5) sell or offer for sale in interstate or foreign 
commerce. Certain exceptions to these prohibitions apply to employees 
or agents of the Service, the National Marine Fisheries Service, other 
Federal land management agencies, and State conservation agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered wildlife under certain circumstances. Regulations 
governing permits for endangered wildlife are codified at 50 CFR 17.22, 
and general Service permitting regulations are codified at 50 CFR part 
13. With regard to endangered wildlife, a permit may be issued: for 
scientific purposes, for enhancing the propagation or survival of the 
species, or for take incidental to otherwise lawful activities. The 
statute also contains certain exemptions from the prohibitions, which 
are found in sections 9 and 10 of the Act.

II. Protective Regulations Under Section 4(d) of the Act

Background

    As discussed in Available Conservation Measures, section 9 of the 
Act provides a specific list of prohibitions for endangered species but 
does not provide these same prohibitions for threatened species. 
Instead, pursuant to section 4(d) of the Act, for any species listed as 
a threatened species, the Secretary must issue protective regulations 
that are ``necessary and advisable to provide for the conservation of 
such species'' (these are referred to as ``4(d) rules''). Section 4(d) 
of the Act contains two sentences. The first sentence states that the 
Secretary shall issue such regulations as she deems necessary and 
advisable to provide for the conservation of species listed as 
threatened species. Conservation is defined in the Act to mean the use 
of all methods and procedures which are necessary to bring any 
endangered species or threatened species to the point at which the 
measures provided pursuant to the Act are no longer necessary. 
Additionally, the second sentence of section 4(d) of the Act states 
that the Secretary may by regulation prohibit with respect to any 
threatened species any act prohibited under section 9(a)(1), in the 
case of fish or wildlife, or section 9(a)(2), in the case of plants. 
With these two sentences in section 4(d), Congress delegated broad 
authority to the Secretary to determine what protections would be 
necessary and advisable to provide for the conservation of threatened 
species, and even broader authority to put in place any of the section 
9 prohibitions, for a given species.
    Courts have recognized the extent of the Secretary's discretion 
under section 4(d) to develop regulations that are appropriate for the 
conservation of threatened species. For example, courts have upheld, as 
a valid exercise of agency authority, rules developed under section 
4(d) that included limited prohibitions against takings (see Alsea 
Valley Alliance v. Lautenbacher, 2007 WL 2344927 (D. Or. 2007); 
Washington Environmental Council v. National Marine Fisheries Service, 
2002 WL 511479 (W.D. Wash. 2002)). Courts have also upheld 4(d) rules 
that do not address all of the threats a species faces (see State of 
Louisiana v. Verity, 853 F.2d 322 (5th Cir. 1988)). As noted in the 
legislative history when the Act was initially enacted, ``once an 
animal is on the threatened list, the Secretary has an almost infinite 
number of options available to [her] with regard to the permitted 
activities for those species. [She] may, for example, permit taking, 
but not importation of such species, or [she] may choose to forbid both 
taking and importation but allow the transportation of such species'' 
(H.R. Rep. No. 412, 93rd Cong., 1st Sess. 1973).
    Under our 4(d) authorities, we put in place protections intended to 
both prevent a threatened species from becoming an endangered species 
and to promote its recovery. We have two ways to put in place these 
protections for a threatened species: (1) we can issue a species-
specific 4(d) rule (at 50 CFR 17.40-17.47 or 17.73-17.74), which would 
contain all of the protective regulations for that species; or (2) we 
can apply a ``blanket rule'' (for more information, see 89 FR 23919, 
April 5, 2024), which extends to threatened species without a species-
specific rule all of the prohibitions that apply to endangered species 
under section 9 (with certain exceptions applicable to threatened 
species).
    Both ``blanket rules'' and species-specific 4(d) rules explain what 
is prohibited for a threatened species, thus making the activity 
unlawful without a permit or authorization under the Act for the 
prohibited activity unless otherwise excepted in the 4(d) rule 
(species-specific 4(d) rules may also include affirmative 
requirements). Section 4(d) rules are therefore directly related to 
what actions may require permits in the future. As discussed in 
Available Conservation Measures, permits may be issued for purposes 
described in our threatened species permitting regulations at 50 CFR 
17.32 and 17.72, including for recovery actions, conservation benefit 
agreements (previously referred to as candidate conservation agreements 
with assurances and safe harbor agreements), or habitat conservation 
plans. We may also except otherwise prohibited activities through a 
4(d) rule itself, in which case threatened species permits would not be 
required for those activities. For example, there are two categories of 
exceptions that we frequently include in 4(d) rules, and these are for 
otherwise prohibited acts or forms or amounts of ``take'' that are: (1) 
unavoidable while conducting beneficial actions for the species, or (2) 
considered inconsequential (de minimis) to the conservation of the 
species. For otherwise prohibited take activities that require section 
10 permits, programmatic approaches--such as general conservation plans 
and template habitat conservation plans--may be available as another 
way for project proponents to comply with take prohibitions or 
requirements applicable to one or more species while reducing the time 
that would otherwise be associated with developing individual permit 
applications. In addition, the Service and project proponents can 
reduce the need for such permits by developing standardized 
conservation measures that avoid the risk of ``take.''
    The provisions of the Culebra skink's proposed protective 
regulations under section 4(d) of the Act are one of many tools that we 
would use to promote the conservation of the Culebra skink. The 
proposed protective regulations would apply only if and when we make 
final the listing of the Culebra skink as a threatened species. Nothing 
in 4(d) rules changes in any way the recovery planning provisions of 
section 4(f) of the Act, the consultation requirements under section 7 
of the Act, or the ability

[[Page 103964]]

of the Service to enter into partnerships for the management and 
protection of the Culebra skink.
    As mentioned previously in Available Conservation Measures, section 
7(a)(2) of the Act requires Federal agencies, including the Service, to 
ensure that any action they authorize, fund, 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, even 
before the listing of any species or the designation of its critical 
habitat is finalized, 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 critical habitat proposed to be designated for such 
species. These requirements are the same for a threatened species 
regardless of what is included in its 4(d) rule.
    Section 7 consultation is required for Federal actions that ``may 
affect'' a listed species regardless of whether take caused by the 
activity is prohibited or excepted by a 4(d) rule (under application of 
a ``blanket rule'' or a species-specific 4(d) rule). For example, as 
with an endangered species, a Federal agency's determination that an 
action is ``not likely to adversely affect'' a threatened species 
requires the Service's written concurrence (50 CFR 402.13(c)). 
Similarly, if a Federal agency determines that an action is ``likely to 
adversely affect'' a threatened species, the action will require formal 
consultation with the Service and the formulation of a biological 
opinion (50 CFR 402.14(a)). Because consultation obligations and 
processes are unaffected by 4(d) rules, we may consider developing 
tools to streamline future intra-Service and inter-agency consultations 
for actions that result in forms of take that are not prohibited by the 
4(d) rule (but that still require consultation). These tools may 
include consultation guidance, online consultation processes via the 
Service's digital project planning tool (Information for Planning and 
Consultation; https://ipac.ecosphere.fws.gov/), template language for 
biological opinions, or programmatic consultations.

Provisions of the Proposed 4(d) Rule

    Exercising the Secretary's authority under section 4(d) of the Act, 
we have developed a proposed rule that is designed to address the 
Culebra skink's conservation needs. As discussed previously in Summary 
of Biological Status and Threats, we have concluded that the Culebra 
skink is likely to become in danger of extinction within the 
foreseeable future primarily due to nonnative predators and sea level 
rise. Section 4(d) requires the Secretary to issue such regulations as 
she deems necessary and advisable to provide for the conservation of 
each threatened species and authorizes the Secretary to include among 
those protective regulations any of the prohibitions that section 
9(a)(1) of the Act prescribes for endangered species. We are not 
required to make a ``necessary and advisable'' determination when we 
apply or do not apply specific section 9 prohibitions to a threatened 
species (In re: Polar Bear Endangered Species Act Listing and 4(d) Rule 
Litigation, 818 F. Supp. 2d 214, 228 (D.D.C. 2011) (citing Sweet Home 
Chapter of Communities for a Great Oregon v. Babbitt, 1 F.3d 1, 8 (D.C. 
Cir. 1993), rev'd on other grounds, 515 U.S. 687 (1995))). 
Nevertheless, even though we are not required to make such a 
determination, we have chosen to be as transparent as possible and 
explain below why we find that, if finalized, the protections, 
prohibitions, and exceptions in this proposed rule as a whole satisfy 
the requirement in section 4(d) of the Act to issue regulations deemed 
necessary and advisable to provide for the conservation of the Culebra 
skink.
    The protective regulations we are proposing for the Culebra skink 
incorporate prohibitions from section 9(a)(1) to address the threats to 
the species. The prohibitions of section 9(a)(1) of the Act, and 
implementing regulations codified at 50 CFR 17.21, make it illegal for 
any person subject to the jurisdiction of the United States to commit, 
to attempt to commit, to solicit another to commit or to cause to be 
committed any of the following acts with regard to any endangered 
wildlife: (1) import into, or export from, the United States; (2) take 
(which includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect, or to attempt to engage in any such conduct) 
within the United States, within the territorial sea of the United 
States, or on the high seas; (3) possess, sell, deliver, carry, 
transport, or ship, by any means whatsoever, any such wildlife that has 
been taken illegally; (4) deliver, receive, carry, transport, or ship 
in interstate or foreign commerce, by any means whatsoever and in the 
course of commercial activity; or (5) sell or offer for sale in 
interstate or foreign commerce. This protective regulation includes all 
of these prohibitions for the Culebra skink because the Culebra skink 
is at risk of extinction within the foreseeable future, and putting 
these prohibitions in place will help to prevent further declines, 
preserve the species' remaining populations, and decrease potential 
synergistic, negative effects from other ongoing or future threats.
    In particular, this proposed 4(d) rule would provide for the 
conservation of the Culebra skink by prohibiting the following 
activities, unless they fall within specific exceptions or are 
otherwise authorized or permitted: importing or exporting; take; 
possession and other acts with unlawfully taken specimens; delivering, 
receiving, carrying, transporting, or shipping in interstate or foreign 
commerce in the course of commercial activity; or selling or offering 
for sale in interstate or foreign commerce.
    Under the Act, ``take'' means to harass, harm, pursue, hunt, shoot, 
wound, kill, trap, capture, or collect, or to attempt to engage in any 
such conduct. Some of these provisions have been further defined in 
regulations at 50 CFR 17.3. Take can result knowingly or otherwise, by 
direct and indirect impacts, intentionally or incidentally. Regulating 
take would help preserve the species' remaining populations, slow their 
rate of decline, and decrease cumulative effects from other ongoing or 
future threats. Therefore, we propose to prohibit take of the Culebra 
skink, except for take resulting from those actions and activities 
specifically excepted by the 4(d) rule.
    Exceptions to the prohibition on take would include all of the 
general exceptions to the prohibition on take of endangered wildlife as 
set forth in 50 CFR 17.21 and additional exceptions, as described 
below.
    Despite these prohibitions regarding threatened species, we may 
under certain circumstances issue permits to carry out one or more 
otherwise-prohibited activities, including those described above. The 
regulations that govern permits for threatened wildlife state that the 
Director may issue a permit authorizing any activity otherwise 
prohibited with regard to threatened species. These include permits 
issued for the following purposes: for scientific purposes, to enhance 
propagation or survival, for economic hardship, for zoological 
exhibition, for educational purposes, for incidental taking, or for 
special purposes consistent with the purposes of the Act (50 CFR 
17.32). The statute also contains certain exemptions from the 
prohibitions, which are found in sections 9 and 10 of the Act.

[[Page 103965]]

    In addition, to further the conservation of the species, any 
employee or agent of the Service, any other Federal land management 
agency, the National Marine Fisheries Service, a State conservation 
agency, or a federally recognized Tribe, who is designated by their 
agency or Tribe for such purposes, may, when acting in the course of 
their official duties, take threatened wildlife without a permit if 
such action is necessary to: (i) Aid a sick, injured, or orphaned 
specimen; or (ii) dispose of a dead specimen; or (iii) salvage a dead 
specimen that may be useful for scientific study; or (iv) remove 
specimens that constitute a demonstrable but nonimmediate threat to 
human safety, provided that the taking is done in a humane manner; the 
taking may involve killing or injuring only if it has not been 
reasonably possible to eliminate such threat by live-capturing and 
releasing the specimen unharmed, in an appropriate area.
    We recognize the special and unique relationship with our State 
natural resource agency partners in contributing to conservation of 
listed species. State agencies often possess scientific data and 
valuable expertise on the status and distribution of endangered, 
threatened, and candidate species of wildlife and plants. State 
agencies, because of their authorities and their close working 
relationships with local governments and landowners, are in a unique 
position to assist us in implementing all aspects of the Act. In this 
regard, section 6 of the Act provides that we must cooperate to the 
maximum extent practicable with the States in carrying out programs 
authorized by the Act. Therefore, any qualified employee or agent of a 
State conservation agency that is a party to a cooperative agreement 
with us in accordance with section 6(c) of the Act, who is designated 
by their agency for such purposes, would be able to conduct activities 
designed to conserve the Culebra skink that may result in otherwise 
prohibited take without additional authorization.
    The proposed 4(d) rule would also provide for the conservation of 
the species by allowing exceptions that incentivize conservation 
actions or that, while they may have some minimal level of take of the 
Culebra skink, are not expected to rise to the level that would have a 
negative impact (i.e., would have only de minimis impacts) on the 
species' conservation. The proposed exceptions to these prohibitions 
include predator control or eradication efforts and habitat restoration 
efforts (described below) that are expected to have negligible impacts 
to the Culebra skink and its habitat:
    (1) Eradication or control of nonnative species such as mongooses, 
rats, cats, pigs, goats, etc., is beneficial for skinks. Permanent 
eradication of nonnative species is typically most effective on small 
islands that do not have human development, as introductions (whether 
passive or intentional) happen often in the presence of humans. 
However, any activities intended to reduce or eliminate nonnative 
species will benefit the Culebra skink.
    (2) Habitat management or restoration activities expected to 
provide a benefit to the Culebra skink and other sensitive species, 
including removal of nonnative, invasive plants. These activities must 
be coordinated with and reported to the Service in writing and approved 
the first time an individual or agency undertakes them or if there are 
planned changes to the activities.
    We ask the public, particularly State agencies and other interested 
stakeholders that may be affected by the proposed 4(d) rule, to provide 
comments and suggestions regarding additional guidance and methods that 
we could provide or use, respectively, to streamline the implementation 
of this proposed 4(d) rule (see Information Requested, above).

III. Critical Habitat

Background

    Section 4(a)(3) of the Act requires that, to the maximum extent 
prudent and determinable, we designate a species' critical habitat 
concurrently with listing the species. 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 (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(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 each Federal action agency 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 designated critical habitat. The designation of 
critical habitat does not affect land ownership or establish a refuge, 
wilderness, reserve, preserve, or other conservation area. Such 
designation also does not allow the government or public to access 
private lands. Such designation does not require implementation of 
restoration, recovery, or enhancement measures by non-Federal 
landowners. Rather, designation requires that, where a landowner 
requests Federal agency funding or authorization for an action that may 
affect an area designated as critical habitat, the Federal agency 
consult with the Service under section 7(a)(2) of the Act. If the 
action may affect the listed species itself (such as for occupied 
critical habitat), the Federal agency would have already been required 
to consult with the Service even absent the designation because of the 
requirement to ensure that the action is not likely to jeopardize the 
continued existence of the species. Even if the Service were to 
conclude after consultation that the proposed activity is likely to 
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

[[Page 103966]]

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 data available, those physical or biological 
features that are essential to the conservation of the species (such as 
space, food, cover, and protected habitat).
    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.
    Section 4(b)(2) 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 from the SSA report and 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 prohibitions found in section 9 of the Act for the 
Puerto Rican skink, Lesser Virgin Islands skink, and Virgin Islands 
bronze skink, or the proposed 4(d) rule for the Culebra skink. 
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 the 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 those planning efforts calls for a 
different outcome.

Physical or Biological Features Essential to the Conservation of the 
Species

    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 
which 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, alkaline 
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 absence of 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, we 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.
    Skinks require sufficient suitable habitat to support population 
needs such as reproductive success, as well as species needs to 
withstand stochastic and catastrophic events, as well as adaptive 
capacity to respond to future environmental change. At theindividual 
level, skinks require suitable foraging, basking and shelter habitat to 
flourish during each life stage from birth to adulthood, and to 
successfully reproduce. These needs can be met by the following habitat 
components that are present in low elevation (below 500 m (0.31 mi)) 
natural (i.e., forest, scrub/shrub, or herbaceous) habitats on the 
islands within the skinks' ranges: (1) trees, shrubs, bushes, ground 
cover/leaf litter, cactus, debris, rocks, and crevices; (2) basking 
locations; and (3) arthropods/insects as a food source. Suitable 
habitat types can vary, but must contain a substrate that provides 
refugia, presence of natural vegetation, areas that offer both canopied 
and

[[Page 103967]]

exposed sections for basking, and food resources.

Summary of Essential Physical or Biological Features

    We derive the specific physical or biological features essential to 
the conservation of the four Caribbean skink species (presented in 
alphabetical order by species common name: Culebra skink, Lesser Virgin 
Islands skink, Puerto Rican skink, and Virgin Islands bronze skink) 
from studies of the species' habitat, ecology, and life history as 
described below. Additional information can be found in the SSA report 
(Service 2023, pp. 8-20; available on https://www.regulations.gov under 
Docket No. FWS-R4-ES-2024-0154). We have determined that the following 
physical or biological features are essential to the conservation of 
each of the skink species, as detailed below.
Culebra Skink
    (1) Forest, shrub/scrub, and herbaceous habitat types below 500 m 
(0.31 mi) elevation on Culebra, Cayo Agua, Cayo Botella, Cayo Lobito, 
and Cayo Yerba.
    (2) Sufficient, appropriate ground cover (including but not limited 
to leaf litter, rocks, and vegetative debris) for protection from 
predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
Lesser Virgin Islands Skink
    (1) Forest, shrub/scrub, and herbaceous habitat types on Hans 
Lollik Island, USVI.
    (2) Sufficient, appropriate ground cover (including but not limited 
to leaf litter, rocks, and vegetative debris) for protection from 
predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
Puerto Rican Skink
    (1) Forest and shrub/scrub habitat types below 500 m (0.31 mi) 
elevation on mainland Puerto Rico and on Desecheo Island.
    (2) Sufficient, appropriate ground cover (including but not limited 
to leaf litter, rocks, and vegetative debris) for protection from 
predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
Virgin Islands Bronze Skink
    (1) Forest, shrub/scrub, and herbaceous habitat types on Buck 
Island, Turtledove Cay, and Water Island, USVI.
    (2) Sufficient, appropriate ground cover (including but not limited 
to leaf litter, rocks, and vegetative debris) for protection from 
predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.

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.
    The features essential to the conservation of these species may 
require special management considerations or protection to reduce 
threats from nonnative species, habitat loss and degradation, and sea 
level rise. Special management considerations or protection may be 
required within critical habitat areas to address these threats. 
Management activities that could ameliorate these threats include, but 
are not limited to restoration, protection, and conservation of the 
habitat and wildlife resources and plant communities. These management 
activities would protect the physical or biological features for the 
species and ensure protection from predators, refugia from temperature 
extremes, sources of food, and areas for reproduction.

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 to be considered 
for designation as critical habitat. 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 that are essential to the 
conservation of the species.
    Sources of data for these proposed critical habitat designations 
include information from PRDNER and the U.S. Virgin Islands Department 
of Planning and Natural Resources and reports from surveys throughout 
the species' ranges (Service 2023, entire). We have reviewed available 
information that pertains to the habitat requirements of these species. 
Sources of information on habitat requirements include surveys of 
occupied sites and published peer-reviewed articles, agency reports, 
and data collected during monitoring efforts (Service 2023, entire).
    For areas within the geographical area occupied by the species at 
the time of listing, we delineated critical habitat unit boundaries 
using the following criteria:
    (1) All islands, or for Puerto Rico and Culebra, all areas 
currently occupied by skinks based on surveys conducted from 2012 to 
present, using the population definition from the SSA report (Service 
2023, p. 57). The timeframe for current was determined to be a 10-year 
window (since 2012, when analyses were performed in 2022) encompassing 
recent survey efforts; this timeframe is appropriate given the short 
lifespan of the species and their known responses to threats, such as 
nonnative predators. Populations are defined as single island units; 
however, for mainland Puerto Rico, multiple areas separated by 
substantial distance show similar levels of genetic differentiation to 
what we see between islands with the same species (Rivera et al. 2023, 
pp. 15-16). Therefore, on Puerto Rico we defined multiple populations 
of Puerto Rican skink (in addition to Desecheo Island).
    (2) For Puerto Rico and Culebra, we included suitable habitat below 
500-m elevation adjacent to known populations within 6-km diameter 
hexagons that were used in the Puerto Rico GAP analysis project (Gould 
et al. 2008, p. 91). Since skinks are habitat generalists, suitable 
habitat was defined using land cover classes from the Coastal Change 
Analysis Program 2010 high-resolution imagery for Puerto Rico, 
including mixed forest, shrub/scrub, and herbaceous vegetation classes 
(NOAA-OCM 2024a, unpaginated). We omitted all developed areas 
(including roads), cultivated crops, pasture/hay, and wetland areas.
    (3) For USVI, we considered all islands with known skink 
populations. For Water Island, we included all suitable habitat, which 
was defined using land cover classes from the Coastal Change Analysis 
Program 2012 high-resolution imagery for the U.S. Virgin Islands, 
including all forest classes, shrub/scrub, and herbaceous vegetation 
classes (NOAA-OCM 2024b, unpaginated). We omitted all developed areas 
(including roads), cultivated crops, pasture/hay, and wetland areas. 
The timeframe for current was determined to be a 10-year window (since 
2012, when analyses were performed in 2022) encompassing recent survey 
efforts; this timeframe is appropriate given the short lifespan of

[[Page 103968]]

the species and their known responses to threats, such as nonnative 
predators.
    (4) We did not include areas in the BVI, as regulations prohibit 
the Service from designating critical habitat in non-U.S. areas.
    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 each of the skink 
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 propose to designate as critical habitat lands that we have 
determined are occupied at the time of listing (i.e., currently 
occupied) and that contain one or more of the physical or biological 
features that are essential to support life-history processes of the 
skink species. All units contain all of the identified physical or 
biological features and support multiple life-history processes.
    The proposed critical habitat designation is defined by the map or 
maps, as modified by any accompanying regulatory text, presented at the 
end of this document under Proposed Regulation Promulgation.

Proposed Critical Habitat Designation

Culebra Skink

    We are proposing to designate approximately 5,648 ac (2,286 ha) in 
five units as critical habitat for the Culebra skink. The critical 
habitat areas we describe below constitute our current best assessment 
of areas that meet the definition of critical habitat for the Culebra 
skink. The five areas we propose as critical habitat are: (1) Culebra 
Island Unit, (2) Cayo Botella Unit, (3) Cayo del Agua Unit, (4) Cayo 
Yerba Unit, and (5) Cayo Lobito Unit. Table 12 shows the proposed 
critical habitat units, the approximate area of each unit, and land 
ownership for each unit. All units are considered occupied by the 
species and contain all of the physical or biological features 
essential to the conservation of the species.

                         Table 12--Proposed Critical Habitat Units for the Culebra Skink
                   [Area estimates reflect all land within critical habitat unit boundaries.]
----------------------------------------------------------------------------------------------------------------
                                                                       Size of unit
          Critical habitat unit             Land ownership by type       in acres              Occupied?
                                                                        (hectares)
----------------------------------------------------------------------------------------------------------------
CUL-1 Culebra Island....................  USFWS.....................       609 (246)  Yes.
                                          Private...................   5,022 (2,032)  ..........................
CUL-2 Cayo Botella......................  USFWS.....................           4 (2)  Yes.
CUL-3 Cayo del Agua.....................  USFWS.....................           3 (1)  Yes.
CUL-4 Cayo Yerba........................  USFWS.....................           3 (1)  Yes.
CUL-5 Cayo Lobito.......................  USFWS.....................           7 (3)  Yes.
                                                                     -------------------------------------------
    Total...............................  ..........................   5,648 (2,286)  ..........................
----------------------------------------------------------------------------------------------------------------
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 the Culebra skink, below.

Unit CUL-1: Culebra

    Unit CUL-1 consists of 5,631 ac (2,279 ha) of Culebra Island, 
approximately 18 miles (29 km) east from the northeastern corner of 
Puerto Rico. The majority of this unit, 89 percent (5,022 ac (2,032 
ha)), is composed of private land, while 11 percent (609 ac (246 ha)) 
is managed for conservation as part of the Culebra NWR (Service 2012a, 
entire). Less than 1 percent of the private areas is also managed for 
conservation by PLN, as the Cerro Feliz Natural Protected Area. The 
primary threat to the skink habitat in Unit CUL-1 is habitat 
destruction and modification (e.g., urban development, including single 
family house construction, tourist development projects, and 
transportation) and predation from nonnative predators, mainly cats and 
rats. Special management considerations to manage nonnative predators 
and to protect the habitat from development may be required within this 
unit.

Unit CUL-2: Cayo Botella

    Unit CUL-2 consists of the entire Cayo Botella (4 ac (2 ha)), 
approximately 1 mile (1.6 km) from the northeastern coast of Culebra 
Island, and in between Isla Culebrita and Cayo Norte. Cayo Botella is 
managed for conservation as part of the Culebra NWR (Service 2012a, 
entire). Ongoing management activities include restoration, protection, 
and conservation of the habitat and wildlife resources and plant 
communities. Threats to the habitat in this unit are considered minimal 
since Cayo Botella is managed for conservation; it is closed to the 
general public, and there are currently no nonnative predators present.

Unit CUL-3: Cayo del Agua

    Unit CUL-3 consists of the entire Cayo del Agua (3 ac (1 ha)), 
approximately 1 mile (1.6 km) from the west coast of Culebra Island and 
less than 1 mile (1.6 km) west from Cayo Luis Pe[ntilde]a. Cayo del 
Agua is managed for conservation as part of the Culebra NWR (Service 
2012a, entire). Ongoing management activities include restoration, 
protection, and conservation of the habitat and wildlife resources and 
plant communities. Threats to the habitat in this unit are considered 
minimal since Cayo del Agua is managed for conservation, it is closed 
to the general public, and no nonnative predators are currently 
present.

Unit CUL-4: Cayo Yerba

    Unit CUL-4 consists of the entire Cayo Yerba (3 ac (1 ha)), 
approximately 2 miles (3 km) from the west coast of Culebra Island and 
less than 1 mile (1.6 km) northwest from Cayo del Agua (Unit CUL-3). 
Cayo Yerba is managed

[[Page 103969]]

for conservation as part of the Culebra NWR (Service 2012a, entire). 
Ongoing management activities include restoration, protection, and 
conservation of the habitat and wildlife resources and plant 
communities. Threats to the habitat in this unit are considered minimal 
since Cayo Yerba is managed for conservation, it is closed to the 
general public, and no nonnative predators are currently present.

Unit CUL-5: Cayo Lobito

    Unit CUL-5 consists of the entire Cayo Lobito (7 ac (3 ha)), 
approximately 4 miles (6 km) from the northwest coast of Culebra Island 
and 3 miles (5 km) northwest from Cayo Yerba (Unit CUL-4). Cayo Lobito 
is managed for conservation as part of the Culebra NWR (Service 2012a, 
entire). Ongoing management activities include restoration, protection, 
and conservation of the habitat and wildlife resources and plant 
communities. Threats to the habitat in this unit are considered minimal 
since Cayo Lobito is managed for conservation, it is closed to the 
general public, and no nonnative predators are currently present.

Lesser Virgin Islands Skink

    We are proposing one unit as critical habitat for the Lesser Virgin 
Islands skink. The critical habitat area we describe below constitutes 
our current best assessment of areas that meet the definition of 
critical habitat for the Lesser Virgin Islands skink. The area we 
propose as critical habitat is the Hans Lollik Island Unit. Table 13 
shows the proposed critical habitat unit, the approximate area of the 
unit, and land ownership for the unit.

                  Table 13--Proposed Critical Habitat Unit for the Lesser Virgin Islands Skink
                   [Area estimate reflects all land within critical habitat unit boundaries.]
----------------------------------------------------------------------------------------------------------------
                                                                       Size of unit
          Critical habitat unit             Land ownership by type       in acres              Occupied?
                                                                        (hectares)
----------------------------------------------------------------------------------------------------------------
LVIS-1 Hans Lollik Island...............  Private...................       477 (193)  Yes.
----------------------------------------------------------------------------------------------------------------

    We present a brief description of the unit, and reasons why it 
meets the definition of critical habitat for the Lesser Virgin Islands 
skink, below.

Unit LVIS-1: Hans Lollik Island

    Unit LVIS-1 consists of the entire Hans Lollik Island (477 (193 
ha)), approximately 2 miles (3 km) north from the north-central coast 
of St. Thomas, USVI. Hans Lollik is a private island managed by Wild 
Ecology Group for conservation on behalf of its owners, and it contains 
all the physical and biological features for the species. Ongoing 
management activities include trail maintenance and restoration of the 
habitat and wildlife resources. The primary threat to the skink habitat 
in Unit LVIS-1 is habitat modification from nonnative goats that 
degrade and damage the native vegetation. Although development has been 
proposed in the past (Platenberg and Valiulis 2018, p. 77), there is no 
current threat to habitat from development.

Puerto Rican Skink

    We are proposing to designate approximately 143,947 ac (58,253 ha) 
in five units as critical habitat for the Puerto Rican skink. The 
critical habitat areas we describe below constitute our current best 
assessment of areas that meet the definition of critical habitat for 
the Puerto Rican skink. The five areas we propose as critical habitat 
are: (1) Quebradillas Unit, (2) Florida Unit, (3) Southwest Unit, (4) 
Ponce Unit, and (5) Desecheo Island Unit. Table 11 shows the proposed 
critical habitat units, the approximate area of each unit and land 
ownership for each unit. All units are considered occupied by the 
species and contain all of the physical or biological features 
essential to the conservation of the species.

                      Table 11--Proposed Critical Habitat Units for the Puerto Rican Skink
                   [Area estimates reflect all land within critical habitat unit boundaries.]
----------------------------------------------------------------------------------------------------------------
                                                                     Size of unit in
         Critical habitat unit            Land ownership by type    acres (hectares)           Occupied?
----------------------------------------------------------------------------------------------------------------
PR-1 Quebradillas, PR.................  Commonwealth (PRDNER)....         2,382 (964)  Yes.
                                        Private..................     34,711 (14,047)  .........................
PR-2 Florida, PR......................  U.S. Department of                    89 (36)  Yes.
                                         Agriculture.
                                        Commonwealth (PRDNER)....           822 (333)  .........................
                                        Private..................     31,841 (12,886)  .........................
PR-3 Southwest, PR....................  Commonwealth (PRDNER)....       6,913 (2,798)  Yes.
                                        Private..................     44,784 (18,123)  .........................
PR-4 Ponce, PR........................  Commonwealth (PRDNER)....            195 (79)  Yes.
                                        Private..................      21,855 (8,844)  .........................
PR-5 Desecheo Island..................  USFWS....................           355 (144)  Yes.
                                                                  ----------------------------------------------
    Total.............................  .........................    143,947 (58,253)  .........................
----------------------------------------------------------------------------------------------------------------
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 the Puerto Rican skink, 
below.

Unit PR-1: Quebradillas

    Unit PR-1 consists of 37,093 ac (15,011 ha) located in northwest 
Puerto Rico. This unit is bounded by the selected PR GAP hexagons 
(Gould et al. 2008, pp. 2-3) that contain forested areas along its 
north boundary within the Municipalities (east to west) of Camuy, 
Quebradillas, Isabela, and

[[Page 103970]]

Moca, and moving south towards San Sebast[iacute]an, and east back to 
Camuy.
    Most of this unit, 94 percent (34,711 ac), is composed of private 
land, while 6 percent (2,382 ac) is considered public and managed for 
conservation as the Guajataca Commonwealth Forest and the Lago 
Guajataca Wildlife Refuge. Approximately 2 percent of the private areas 
are also managed for conservation by Para La Naturaleza (PLN), the 
management unit of the Puerto Rico Conservation Trust, as the 
Montadero, Los Garc[iacute]a, and Terra Firme Natural Protected Areas.
    The primary threat to the skink habitat in Unit PR-1 is habitat 
destruction and modification (e.g., urban development, including single 
family house construction, large-scale residential projects, tourist 
development projects, and transportation) and predation from nonnative 
predators, mainly mongooses, cats, and rats. Special management 
considerations to manage nonnative predators and to protect the habitat 
from development may be required within this unit.

Unit PR-2: Florida

    Unit PR-2 consists of 32,752 ac (13,254 ha) located in north-
central Puerto Rico. This unit is bounded by the selected PR GAP 
hexagons (Gould et al. 2008, pp. 2-3) that contain forested areas along 
its north boundary within the Municipalities (east to west) of 
Manat[iacute], Barceloneta, and Arecibo, and moving south towards 
Utuado and Ciales, and east back to Manat[iacute].
    Most of this unit, 97 percent (31,841 ac), is composed of private 
land, while 3 percent (911 ac) is considered public and managed for 
conservation as the Cambalache Commonwealth Forest. Approximately 6 
percent (1,851 ac) of the private areas are also managed for 
conservation by PLN as part of the R[iacute]o Encantado Natural 
Protected Area. Less than 1 percent (89 ac) is managed by the USDA as 
the Manat[iacute] Research Area.
    The primary threat to the skink habitat in Unit PR-2 is habitat 
destruction and modification (e.g., urban development, including single 
family house construction, large-scale residential projects, tourist 
development projects, and transportation) and predation from nonnative 
predators, mainly mongooses, cats, and rats. Special management 
considerations to manage nonnative predators and to protect the habitat 
from development may be required within this unit.

Unit PR-3: Southwest

    Unit PR-3 consists of 51,697 ac (20,921 ha) located in southwestern 
Puerto Rico. This unit is bounded by the selected PR GAP hexagons 
(Gould et al. 2008, pp. 2-3) that contain forested areas along its 
north boundary within the Municipalities (east to west) of Yauco, 
Maricao, Las Mar[iacute]as, Mayag[uuml]ez, and San Germ[aacute]n, and 
moving south towards Cabo Rojo, Lajas, and Sabana Grande, and east back 
to Yauco.
    Most of this unit, 87 percent (44,784 ac), is composed of private 
land, while 13 percent (6,913 ac) is considered public and managed for 
conservation as the Maricao and Sus[uacute]a Commonwealth Forests. 
Approximately 1 percent (394 ac) of the private areas is also managed 
for conservation by PLN as part of the R[iacute]o Maricao Natural 
Protected Area.
    The primary threat to the skink habitat in Unit PR-3 is habitat 
destruction and modification (e.g., urban development, including single 
family house construction, large-scale residential projects, tourist 
development projects, and transportation) and predation from nonnative 
predators, mainly mongooses, cats, and rats. Special management 
considerations to manage nonnative predators and to protect the habitat 
from development may be required within this unit.

Unit PR-4: Ponce

    Unit PR-4 consists of 22,050 ac (8,923 ha) located in south-central 
Puerto Rico. This unit is bounded by the selected PR GAP hexagons 
(Gould et al. 2008, pp. 2-3) that contain forested areas across its 
north and south boundary within the Municipalities (east to west) of 
Villalba, Juana D[iacute]az, and Ponce.
    Most of this unit, 99 percent (21,855 ac), is composed of private 
land, while approximately 1 percent (195 ac) is considered public and 
managed for conservation as the Cerrillos and Toro Negro Commonwealth 
Forests. Less than 1 percent (86 ac) of a private area known as the 
Picaflor Conservation Easement is managed by PLN.
    The primary threat to the skink habitat in Unit PR-4 is habitat 
destruction and modification (e.g., urban development, including single 
family house construction, large-scale residential projects, tourist 
development projects, and transportation) and predation from nonnative 
predators, mainly mongooses, cats, and rats. Special management 
considerations to manage nonnative predators and to protect the habitat 
from development may be required within this unit.

Unit PR-5: Desecheo Island

    Unit PR-5 consists of the entire Desecheo Island (355 ac (144 ha)) 
in the Mona Passage, approximately 13 mi (21 km) from the closest point 
off the west coast of Puerto Rico. Desecheo Island is managed for 
conservation as a National Wildlife Refuge (Service 2012b, entire), and 
management activities include restoration, protection, and conservation 
of the habitat and wildlife resources and plant communities. Threats to 
the habitat in this unit are considered minimal since Desecheo is 
managed for conservation, it is closed to the general public, and no 
nonnative predators are currently present.

Virgin Islands Bronze Skink

    We are proposing three units as critical habitat for the Virgin 
Islands bronze skink. The critical habitat areas we describe below 
constitute our current best assessment of areas that meet the 
definition of critical habitat for the Virgin Islands bronze skink. The 
three areas we propose as critical habitat are: (1) Water Island Unit, 
(2) Buck Island Unit, and (3) Turtledove Cay Unit. Table 14 shows the 
proposed critical habitat units, the approximate area of each unit, and 
land ownership for each unit.

                  Table 14--Proposed Critical Habitat Units for the Virgin Islands Bronze Skink
                   [Area estimates reflect all land within critical habitat unit boundaries.]
----------------------------------------------------------------------------------------------------------------
                                                                     Size of  unit
         Critical habitat unit             Land ownership by type      in acres               Occupied?
                                                                      (hectares)
----------------------------------------------------------------------------------------------------------------
VBIS-1 Water Island....................  U.S. Territorial                  93 (38)                          Yes.
                                          Government.
                                         Private..................       247 (100)
VBIS-2 Buck Island.....................  USFWS....................         48 (19)                          Yes.
VBIS-3 Turtledove Cay..................  U.S. Territorial                    4 (2)                          Yes.
                                          Government.
                                                                   ---------------------------------------------

[[Page 103971]]

 
    Total..............................  .........................       392 (159)  ............................
----------------------------------------------------------------------------------------------------------------
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 the Virgin Islands bronze 
skink, below.

Unit VIBS-1: Water Island

    Unit VIBS-1 consists of 340 ac (138 ha) of entire Water Island, 
less than 1 mile (1.6 km) south from the south-central coast of St. 
Thomas, USVI, and less than 1 mile (1.6 km) west of Hassel Island. Most 
of this unit, approximately 73 percent (247 ac (100 ha)), is composed 
of private land, of which approximately 12 percent (30 ac (12 ha)) is 
managed for conservation by The Nature Conservancy (Gould et al. 2010, 
entire). Approximately 93 acres (38 ha) are owned by the U.S. 
Territorial Government, but there is no specific information available 
to specify the management purpose of those areas. Water Island contains 
all the physical and biological features for the species. Threats to 
the skink habitat in Unit VIBS-1 may include habitat destruction and 
modification (e.g., urban development, including single family house 
construction, tourist development projects, and transportation) and 
predation from nonnative predators, mainly cats and rats. Special 
management considerations to manage nonnative predators and to protect 
the habitat from development may be required within this unit.

Unit VIBS-2: Buck Island

    Unit VIBS-2 consists of the entire Buck Island (48 ac (19 ha)), 
approximately 2 miles (2 km) south from the southeastern coast of St. 
Thomas, USVI, and just west of Capella Island. Buck Island is managed 
for conservation as the Buck Island NWR (Service 2010, entire) and 
contains all the physical and biological features for the species. The 
principal management objective is to support migratory bird populations 
through habitat restoration and management (Service 2010, p. 16). 
Threats in this unit are considered minimal since Buck Island is 
managed for conservation and no nonnative predators are currently 
present.

Unit VIBS-3: Turtledove Cay

    Unit VIBS-3 consists of the entire Turtledove Cay (4 ac (2 ha)), 
also locally known as Little Saba, approximately 3 miles (4.8 km) south 
from the southwestern coast of St. Thomas, USVI, and approximately 3 
miles west from the southern coast of Water Island (Unit VIBS-1). 
Turtledove Cay is managed for conservation by the Territorial 
Government (Platenberg and Valiulis 2018, p. 81) and contains all the 
physical and biological features for the species. Threats in this unit 
are considered minimal since Turtledove Cay is managed for conservation 
and no nonnative predators are currently present.

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 authorize, fund, 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.
    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 (50 CFR 402.02).
    Compliance with the requirements of section 7(a)(2) 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 formal 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 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 consultation. Reinitiation of consultation is 
required and shall be requested by the Federal agency, where 
discretionary Federal involvement or control over the action has been 
retained or is authorized by law and: (1) If the amount or extent of 
taking specified in the incidental take statement is exceeded; (2) if 
new information reveals effects of the action that may affect listed 
species or critical habitat in a manner or to an extent not previously 
considered; (3) if the identified action is subsequently modified in a 
manner that causes an effect to the listed species or critical habitat 
that was not considered in the biological opinion or written 
concurrence; or (4) if a new species is listed or critical habitat 
designated that may be affected by the identified action. As provided 
in 50 CFR 402.16, the requirement to reinitiate consultations

[[Page 103972]]

for new species listings or critical habitat designation does not apply 
to certain agency actions (e.g., land management plans issued by the 
Bureau of Land Management in certain circumstances).

Destruction or Adverse Modification of Critical Habitat

    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 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 that our Federal Register 
documents ``shall, to the maximum extent practicable also include a 
brief description and evaluation of those activities (whether public or 
private) which, in the opinion of the Secretary, if undertaken may 
adversely modify [critical] habitat, or may be affected by such 
designation.''
    Activities that may be affected by designation of critical habitat 
for the Puerto Rican skink, the Culebra skink, the Lesser Virgin 
Islands skink, and the Virgin Islands bronze skink include those that 
may affect the physical or biological features of each of the species' 
critical habitat (see Physical or Biological Features Essential to the 
Conservation of the Species).

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 (DoD), or designated for its use, that are subject to an 
integrated natural resources management plan (INRMP) prepared under 
section 101 of the Sikes Act Improvement Act of 1997 (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. No DoD lands with a completed INRMP are within the 
proposed critical habitat designations.

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, the impact on national security, and any other 
relevant impact of specifying any particular area as critical habitat. 
The Secretary may exclude any area from critical habitat if the 
benefits of exclusion outweigh those of inclusion, so long as exclusion 
will not result in extinction of the species concerned. Exclusion 
decisions are governed by the regulations at 50 CFR 424.19 and the 
Policy Regarding Implementation of Section 4(b)(2) of the Endangered 
Species Act (hereafter, the ``2016 Policy''; 81 FR 7226, February 11, 
2016), both of which were developed jointly with the National Marine 
Fisheries Service (NMFS). We also refer to a 2008 Department of the 
Interior Solicitor's opinion entitled ``The Secretary's Authority to 
Exclude Areas from a Critical Habitat Designation under Section 4(b)(2) 
of the Endangered Species Act'' (M-37016).
    In considering whether to exclude a particular area from the 
designation, we identify the benefits of including the area in the 
designation, identify the benefits of excluding the area from the 
designation, and evaluate whether the benefits of exclusion outweigh 
the benefits of inclusion. If the analysis indicates that the benefits 
of exclusion outweigh the benefits of inclusion, the Secretary may 
exercise discretion to exclude the area only if such exclusion would 
not 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. In our final rules, we explain any decision to exclude 
areas, as well as decisions not to exclude, to make clear the rational 
basis for our decision. We describe below the process that we use for 
taking into consideration each category of impacts and any initial 
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). Therefore, the baseline 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.
    Executive Order (E.O.) 14094 amends and reaffirms E.O. 12866 and 
E.O. 13563 and directs 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. Section 3(f) of E.O. 
12866 identifies four criteria when a regulation is considered a 
``significant regulatory action'' and requires additional analysis, 
review, and approval if met. The criterion relevant here is whether the 
designation of critical habitat may have an economic effect of $200 
million or more in any given year (section 3(f)(1) of E.O. 12866 as 
amended by E.O. 14094). Therefore,

[[Page 103973]]

our consideration of economic impacts uses a screening analysis to 
assess whether a designation of critical habitat for Puerto Rican 
skink, Culebra skink, Lesser Virgin Islands skink, and Virgin Islands 
bronze sink is likely to exceed the threshold for a regulatory action 
significant under section 3(f)(1) of E.O. 12866, as amended by E.O. 
14094.
    For this particular designation, we developed an incremental 
effects memorandum (IEM) considering the probable incremental economic 
impacts that may result from this proposed 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 Puerto Rican skink, Culebra skink, Lesser 
Virgin Islands skink, and Virgin Islands bronze skink (IEc 2024, 
entire). We began by conducting a screening analysis of the proposed 
designation of critical habitat for each species 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 particular geographical areas of critical habitat that are already 
subject to such protections and are, therefore, unlikely to incur 
incremental economic impacts. In particular, the screening analysis 
considers baseline costs (i.e., absent critical habitat designation) 
and includes any probable incremental economic impacts where land and 
water use may already 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. 
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 presence of the listed species in occupied areas of critical 
habitat means that any destruction or adverse modification of those 
areas is also likely to jeopardize the continued existence of the 
species. Therefore, designating occupied areas as critical habitat 
typically causes little if any incremental impacts above and beyond the 
impacts of listing the species. As a result, we generally focus the 
screening analysis on areas of unoccupied critical habitat (unoccupied 
units or unoccupied areas within occupied units). Overall, the 
screening analysis assesses whether designation of critical habitat is 
likely to result in any additional management or conservation efforts 
that may incur incremental economic impacts. This screening analysis 
combined with the information contained in our IEM constitute what we 
consider to be our economic analysis of the proposed critical habitat 
designation for the Puerto Rican skink, Culebra skink, Lesser Virgin 
Islands skink, and Virgin Islands bronze skink; our economic analysis 
is summarized in the narrative below.
    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 Puerto Rican skink, Culebra 
skink, Lesser Virgin Islands skink, and Virgin Islands bronze skink, 
first we identified, in the IEM dated April 16, 2024, probable 
incremental economic impacts associated with the following categories 
of activities: (1) Federal lands management (U.S. Fish and Wildlife 
Service National Wildlife Refuges); (2) roadway construction; (3) dam 
construction and maintenance; (4) unexploded ordnance management; (5) 
power grid repairs; and (6) commercial or residential development. 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 affects only activities conducted, funded, permitted, 
or authorized by Federal agencies. If we list the species, in areas 
where the Puerto Rican skink, Culebra skink, Lesser Virgin Islands 
skink, or Virgin Islands bronze skink is present, Federal agencies 
would be required to consult with the Service under section 7 of the 
Act on activities they authorize, fund, or carry out that may affect 
the species. If, when we list the species, we also finalize this 
proposed critical habitat designation, Federal agencies would be 
required to consider the effects of their actions on the designated 
habitat, and if the Federal action may affect critical habitat, our 
consultations would include an evaluation of measures to avoid the 
destruction or adverse modification of critical habitat.
    In our IEM, we attempted to clarify the distinction between the 
effects that would 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 Puerto 
Rican skink's, Culebra skink's, Lesser Virgin Islands skink's, or 
Virgin Islands bronze skink's critical habitat. Because the designation 
of critical habitat for each is being proposed concurrently with the 
listing, it has been our experience that it is more difficult to 
discern which conservation efforts are attributable to the species 
being listed and those which will result solely from the designation of 
critical habitat. However, the following specific circumstances in this 
case 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 likely adversely affect the essential physical or 
biological features of occupied critical habitat are also likely to 
adversely affect the species itself. 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 all four skink 
species totals approximately 150,464 ac (60,891 ha) in Puerto Rico and 
the U.S. Virgin Islands, including 143,947 ac (58,253 ha) in 5 units 
for the Puerto Rican skink, 5,648 ac (2,286 ha) in 5 units for the 
Culebra skink, 477 ac (193 ha) in 1 unit for the Lesser Virgin Islands 
skink, and 392 ac (159 ha) in 3 units for the Virgin Islands bronze 
skink. All lands within the proposed designation are considered 
occupied by each species. In the proposed areas, any actions that may 
affect the species or its habitat may also affect designated critical 
habitat, and 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 each skink species. Therefore, only 
administrative costs are expected for the proposed critical habitat 
designations.
    The entities most likely to incur incremental costs are parties to 
section 7 consultations, including Federal action agencies and, in some 
cases, third parties, most frequently State/Territory/Commonwealth 
agencies or municipalities. Activities we expect would be subject to 
consultations that may involve private entities as third parties are 
residential and commercial development that may occur on private lands. 
The probable incremental economic impacts of the skink critical habitat 
designations are expected to be

[[Page 103974]]

limited to additional administrative effort as well as minor costs of 
conservation efforts resulting from a small number of future section 7 
consultations. This limitation is due to the entirety of proposed 
critical habitat areas are considered to be occupied by the species. At 
approximately $10,000 or less per consultation, the burden resulting 
from the designation of critical habitat for each of the four skink 
species, based on the anticipated annual number of consultations and 
associated consultation costs, is not expected to exceed $259,000 (2024 
dollars) in most years. The designation is unlikely to trigger 
additional requirements under Territory, Commonwealth, or local 
regulations. Thus, the annual administrative burden is relatively low.
    Any future probable incremental economic impacts are not likely to 
exceed $200 million in any single year, and impacts that are 
concentrated in any geographical area or sector are not likely as a 
result of this critical habitat designation. Additionally, as described 
in the economic analysis, the analysis is likely conservative, thus 
more likely to overstate than understate the actual number of future 
actions that will result in future consultations (IEc 2024, p. 13).
    We are soliciting data and comments from the public on the economic 
analysis discussed above. During the development of a final 
designation, we will consider the information presented in the economic 
analysis and any additional information on economic impacts we receive 
during the public comment period to determine whether any specific 
areas should be excluded from the final critical habitat designation 
under the authority of section 4(b)(2) of the Act, our implementing 
regulations at 50 CFR 424.19, and the 2016 Policy. 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.

Consideration of National Security Impacts

    Section 4(a)(3)(B)(i) of the Act may not cover all 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), then national-security 
or homeland-security concerns are not a factor in the process of 
determining what areas meet the definition of ``critical habitat.'' 
However, we must still consider impacts on national security, including 
homeland security, on those lands or areas not covered by section 
4(a)(3)(B)(i) because section 4(b)(2) of the Act requires us to 
consider those impacts whenever we designate critical habitat. 
Accordingly, if DoD, the Department of Homeland Security (DHS), or 
another Federal agency has requested exclusion based on an assertion of 
national-security or homeland-security concerns, or we have otherwise 
identified national-security or homeland-security impacts from 
designating particular areas as critical habitat, we generally have 
reason to consider excluding those areas.
    However, 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, we must 
conduct an exclusion analysis if the Federal requester provides 
information, including 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 we conduct an exclusion analysis because the agency provides a 
reasonably specific justification or because we decide to exercise the 
discretion to conduct an exclusion analysis, 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 section 4(b)(2) exclusion analysis, we will give great 
weight to national-security and homeland-security concerns in analyzing 
the benefits of exclusion.
    In preparing this proposal, we have determined that the lands 
within the proposed designation of critical habitat for the Puerto 
Rican skink, the Culebra skink, the Lesser Virgin Islands skink, and 
the Virgin Islands bronze skink are not owned or managed by the DoD or 
DHS. Therefore, we anticipate no impact on national security or 
homeland security.

Consideration of 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 discussed above. To identify other relevant impacts that may 
affect the exclusion analysis, we consider a number of factors, 
including whether there are approved and permitted conservation 
agreements or plans covering the species in the area--such as safe 
harbor agreements (SHAs), candidate conservation agreements with 
assurances (CCAAs) or ``conservation benefit agreements'' or 
``conservation agreements'' (CBAs) (CBAs are a new type of agreement 
replacing SHAs and CCAAs in use after April 2024 (89 FR 26070; April 
12, 2024)) or HCPs--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 whether 
Tribal conservation plans or partnerships, Tribal resources, or 
government-to-government relationships of the United States with Tribal 
entities may be affected by the designation. We also consider any 
State, local, social, or other impacts that might occur because of the 
designation.

Summary of Exclusions Considered Under Section 4(b)(2) of the Act

    In preparing this proposal, we have determined that no HCPs or 
other management plans for the Caribbean skink species currently exist, 
and the proposed designation does not include any Tribal lands or trust 
resources or any lands for which designation would have any economic or 
national security impacts. Therefore, we anticipate no impact on Tribal 
lands, partnerships, or HCPs from this proposed critical habitat 
designation and thus, as described above, we are not considering 
excluding any particular areas on the basis of the presence of 
conservation agreements or impacts to trust resources.
    However, if through the public comment period we receive 
information that we determine indicates that there are potential 
economic, national security, or other relevant impacts from designating 
particular areas as critical habitat, then as part of developing the 
final designation of critical habitat, we will evaluate that 
information and may

[[Page 103975]]

conduct a discretionary exclusion analysis to determine whether to 
exclude those areas under the authority of section 4(b)(2) of the Act 
and our implementing regulations at 50 CFR 424.19. If we receive a 
request for exclusion of a particular area and after evaluation of 
supporting information we do not exclude, we will fully describe our 
decision in the final rule for this action.

Required Determinations

Clarity of the Rule

    We are required by E.O.s 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, 13563, and 
14094)

    Executive Order (E.O.) 14094 amends and reaffirms the principles of 
E.O. 12866 and E.O. 13563 and states that regulatory analysis should 
facilitate agency efforts to develop regulations that serve the public 
interest, advance statutory objectives, and are consistent with E.O.s 
12866, 13563, and 14094. Regulatory analysis, as practicable and 
appropriate, shall recognize distributive impacts and equity, to the 
extent permitted by law. 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.
    E.O. 12866, as reaffirmed by E.O. 13563 and amended by E.O. 14094, 
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.

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; title II of Pub. L. 104-121, March 29, 1996), 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 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 whether 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, as understood in light of recent court 
decisions, Federal agencies are required to evaluate the potential 
incremental impacts of rulemaking on those entities directly regulated 
by the rulemaking itself; in other words, the RFA does not require 
agencies 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, 
only Federal action agencies would be directly regulated if we adopt 
the proposed critical habitat designation. The RFA does not require 
evaluation of 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 proposed 
critical habitat designation will not have a significant economic 
impact on a substantial number of small entities.
    In summary, we have considered whether the 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 proposed 
critical habitat designation would not have a significant economic 
impact on a substantial number of small business entities. Therefore, 
an initial regulatory flexibility analysis is not required.

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 ``to the extent 
permitted by law'' when undertaking actions identified as significant 
energy actions (66 FR 28355; May 22, 2001). E.O. 13211 defines a 
``significant energy action'' as an action that (i) meets the 
definition of a ``significant regulatory action'' under E.O. 12866, as 
amended by E.O. 14094; and (ii) is likely to have a significant adverse 
effect on the supply, distribution, or use of energy. This rule is not 
a significant regulatory action under E.O. 12866 as amended by 14094 
(88 FR 21879, April 11, 2023) as determined by OIRA, and the OIRA 
administrator has not designated this rule as a significant energy 
action.

[[Page 103976]]

Therefore, this action is not a significant energy action, and there is 
no requirement to prepare a statement of energy effects for this 
action.

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 are not likely to 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 believe that this proposed rule would significantly 
or uniquely affect small governments because small governments will be 
affected only to the extent that any programs or agencies using or 
issuing Federal funds, Federal permits, or conducting other authorized 
activities must ensure that their actions will not adversely affect 
critical habitat. 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 the Puerto Rican skink, the Culebra skink, the Lesser 
Virgin Islands skink, and the Virgin Islands bronze skink 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 the Puerto Rican skink, the Culebra skink, the 
Lesser Virgin Islands skink, and the Virgin Islands bronze skink, 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 Federal 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 E.O. 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

[[Page 103977]]

Act. To assist the public in understanding the habitat needs of the 
species, this proposed rule identifies the physical or biological 
features essential to the conservation of the species. The proposed 
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.)

    Regulations adopted pursuant to section 4(a) of the Act are exempt 
from the National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et 
seq.) and do not require an environmental analysis under NEPA. We 
published a notice outlining our reasons for this determination in the 
Federal Register on October 25, 1983 (48 FR 49244). This includes 
listing, delisting, and reclassification rules, as well as critical 
habitat designations and species-specific protective regulations 
promulgated concurrently with a decision to list or reclassify a 
species as threatened. The courts have upheld this position (e.g., 
Douglas County v. Babbitt, 48 F.3d 1495 (9th Cir. 1995) (critical 
habitat); Center for Biological Diversity v. U.S. Fish and Wildlife 
Service, 2005 WL 2000928 (N.D. Cal. Aug. 19, 2005) (concurrent 4(d) 
rule)).

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, May 4, 1994), E.O. 13175 (Consultation and 
Coordination with Indian Tribal Governments), the President's 
memorandum of November 30, 2022 (Uniform Standards for Tribal 
Consultation; 87 FR 74479, December 5, 2022), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with federally recognized 
Tribes and Alaska Native Corporations (ANCs) on a government-to-
government basis. In accordance with Secretary's 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. We have determined that no Tribal lands fall within the 
boundaries of the proposed critical habitat for the Puerto Rican skink, 
the Culebra skink, the Lesser Virgin Islands skink, and the Virgin 
Islands bronze skink, so no Tribal lands would be affected by the 
proposed designation.

References Cited

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

Authors

    The primary authors of this proposed rule are the staff members of 
the Fish and Wildlife Service's Species Assessment Team and the 
Caribbean Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

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

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. In Sec.  17.11, amend paragraph (h) by adding entries for ``Skink, 
Culebra'', ``Skink, Lesser Virgin Islands'', ``Skink, Puerto Rican'', 
and ``Skink, Virgin Islands bronze'' to the List of Endangered and 
Threatened Wildlife in alphabetical order under REPTILES 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
 
                                                  * * * * * * *
Skink, Culebra..................  Spondylurus          Wherever found.....  T                [Federal Register
                                   culebrae.                                                  citation when
                                                                                              published as a
                                                                                              final rule]; 50
                                                                                              CFR 17.42(t); \4d\
                                                                                              50 CFR
                                                                                              17.95(c).\CH\
Skink, Lesser Virgin Islands....  Spondylurus          Wherever found.....  E                [Federal Register
                                   semitaeniatus.                                             citation when
                                                                                              published as a
                                                                                              final rule]; 50
                                                                                              CFR 17.95(c).\CH\
Skink, Puerto Rican.............  Spondylurus nitidus  Wherever found.....  E                [Federal Register
                                                                                              citation when
                                                                                              published as a
                                                                                              final rule]; 50
                                                                                              CFR 17.95(c).\CH\
 
                                                  * * * * * * *
Skink, Virgin Islands bronze....  Spondylurus sloanii  Wherever found.....  E                [Federal Register
                                                                                              citation when
                                                                                              published as a
                                                                                              final rule]; 50
                                                                                              CFR 17.95(c).\CH\
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


[[Page 103978]]

0
3. Amend Sec.  17.42 by adding paragraph (t) to read as follows:


Sec.  17.42  Species-specific rules--reptiles.

* * * * *
    (t) Culebra skink (Spondylurus culebrae).
    (1) Prohibitions. The following prohibitions that apply to 
endangered wildlife also apply to Culebra skink. Except as provided 
under paragraph (t)(2) of this section and Sec. Sec.  17.4 and 17.5, it 
is unlawful for any person subject to the jurisdiction of the United 
States to commit, to attempt to commit, to solicit another to commit, 
or cause to be committed, any of the following acts in regard to this 
species:
    (i) Import or export, as set forth at Sec.  17.21(b) for endangered 
wildlife.
    (ii) Take, as set forth at Sec.  17.21(c)(1) for endangered 
wildlife.
    (iii) Possession and other acts with unlawfully taken specimens, as 
set forth at Sec.  17.21(d)(1) for endangered wildlife.
    (iv) Interstate or foreign commerce in the course of commercial 
activity, as set forth at Sec.  17.21(e) for endangered wildlife.
    (v) Sale or offer for sale, as set forth at Sec.  17.21(f) for 
endangered wildlife.
    (2) Exceptions from prohibitions. In regard to this species, you 
may:
    (i) Conduct activities as authorized by a permit under Sec.  17.32.
    (ii) Take, as set forth at Sec.  17.21(c)(2) through (c)(4) for 
endangered wildlife.
    (iii) Take, as set forth at Sec.  17.31(b).
    (iv) Possess and engage in other acts with unlawfully taken 
wildlife, as set forth at Sec.  17.21(d)(2) for endangered wildlife.
    (v) Take incidental to an otherwise lawful action caused by:
    (A) Activities to eradicate or control nonnative species such as 
mongooses, rats, cats, pigs, goats, etc.
    (B) Habitat management or restoration activities expected to 
provide a benefit to the Culebra skink or other sensitive species, 
including removal of nonnative, invasive plants. These activities must 
be coordinated with and reported to the Service in writing and approved 
the first time an individual or agency undertakes them.
    4. In Sec.  17.95 amend paragraph (c) by adding entries for the 
``Culebra Skink (Spondylurus culebrae)'', ``Lesser Virgin Islands Skink 
(Spondylurus semitaeniatus)'', ``Puerto Rican Skink (Spondylurus 
nitidus)'', and ``Virgin Islands Bronze Skink (Spondylurus sloanii)'', 
after the entry for ``Loggerhead Sea Turtle, Northwest Atlantic Ocean 
DPS (Caretta caretta)'', to read as follows:


Sec.  17.95  Critical habitat--fish and wildlife.

* * * * *
    (c) Reptiles
* * * * *
Culebra Skink (Spondylurus culebrae)
    (1) Critical habitat units are depicted for Culebra Island and 
surrounding cays in Puerto Rico, on the maps in this entry.
    (2) Within these areas, the physical or biological features 
essential to the conservation of Culebra skink consist of the following 
components:
    (i) Forest, shrub/scrub, and herbaceous habitat types below 500 m 
(0.31 mi) elevation on Culebra, Cayo Agua, Cayo Botella, Cayo Lobito, 
and Cayo Yerba.
    (ii) Sufficient, appropriate ground cover (including, but not 
limited to leaf litter, rocks, and vegetative debris) for protection 
from predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
    (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 the final rule.
    (4) Data layers defining map units were created by delineating 
habitats that contain at least one or more of the physical or 
biological features defined in paragraph (2) of this entry. We used the 
digital landcover layer for Puerto Rico created by the National 
Oceanographic and Atmospheric Administration 2010 Coastal Change 
Analysis Program 30m land cover dataset over color infrared imagery 
provided by the United States Army Corps of Engineers. The resulting 
critical habitat units were then mapped using Contiguous Albers North 
American Datum 83 coordinates. The maps in this entry, as modified by 
any accompanying regulatory text, establish the boundaries of the 
critical habitat designation.
    (5) Index map follows:

Figure 1 to Culebra skink (Spondylurus culebrae) paragraph (5)

[[Page 103979]]

[GRAPHIC] [TIFF OMITTED] TP19DE24.003

    (6) Unit CUL-1: Culebra, Puerto Rico.
    (i) Unit CUL-1 consists of 5,631 ac (2,279 ha) of Culebra Island, 
approximately 18 miles (29 km) east from the northeastern corner of 
Puerto Rico. The majority of this unit, 89 percent (5,022 ac), is 
composed of private land, while 11 percent (609 ac) is managed for 
conservation as part of the Culebra National Wildlife Refuge. Less than 
1 percent of the private areas are also managed for conservation by 
Para La Naturaleza, as the Cerro Feliz Natural Protected Area.
    (ii) Map of Unit CUL-1 is at paragraph (7)(ii) of this entry.
    (7) Unit CUL-2: Cayo Botella; Culebra Island, Puerto Rico.
    (i) Unit CUL-2 consists of the entire Cayo Botella (4 ac (2 ha)) 
approximately 1 mile (1.6 km) from the northeastern coast of Culebra 
Island, and in between Isla Culebrita and Cayo Norte. Cayo Botella is 
managed for conservation as part of the Culebra National Wildlife 
Refuge.
    (ii) Map of Units CUL-1 and CUL-2 follows:

Figure 2 to Culebra skink (Spondylurus culebrae) paragraph (7)(ii)

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    (8) Unit CUL-3: Cayo del Agua; Culebra Island, Puerto Rico.
    (i) Unit CUL-3 consists of the entire Cayo del Agua (3 ac (1 ha)), 
approximately 1 mile (1.6 km) from the western coast of Culebra Island 
and less than 1 mile (1.6 km) west from Cayo Luis Pe[ntilde]a. Cayo del 
Agua is managed for conservation as part of the Culebra National 
Wildlife Refuge.
    (ii) Map of Unit CUL-3 is at paragraph (10)(ii) of this entry.
    (9) Unit CUL-4: Cayo Yerba; Culebra Island, Puerto Rico.
    (i) Unit CUL-4 consists of the entire Cayo Yerba (3 ac (1 ha)), 
approximately 2 miles (3 km) from the western coast of Culebra Island 
and less than 1 mile (1.6 km) northwest from Cayo del Agua (Unit CUL-
3). Cayo Yerba is managed for conservation as part of the Culebra 
National Wildlife Refuge.
    (ii) Map of Unit CUL-4 is at paragraph (10)(ii) of this entry.
    (10) Unit CUL-5: Cayo Lobito; Culebra Island, Puerto Rico.
    (i) Unit CUL-5 consists of the entire Cayo Lobito (7 ac (3 ha)), 
approximately 4 miles (6 km) from the northwestern coast of Culebra 
Island and 3 miles (5 km) northwest from Cayo Yerba (Unit CUL-4). Cayo 
Lobito is managed for conservation as part of the Culebra National 
Wildlife Refuge.
    (ii) Map of Units CUL-3, CUL-4, and CUL-5 follows:

Figure 3 to Culebra skink (Spondylurus culebrae) paragraph (10)(ii)

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Lesser Virgin Islands Skink (Spondylurus semitaeniatus)
    (1) A critical habitat unit is depicted for Hans Lollik Island, 
United States Virgin Islands, on the map in this entry.
    (2) Within this area, the physical or biological features essential 
to the conservation of Lesser Virgin Islands skink consist of the 
following components:
    (i) Forest, shrub/scrub, and herbaceous habitat types on Hans 
Lollik Island, United States Virgin Islands.
    (ii) Sufficient, appropriate ground cover (including, but not 
limited to leaf litter, rocks, and vegetative debris) for protection 
from predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
    (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 the final rule.
    (4) Data layers defining map units were created by delineating 
habitats that contain at least one or more of the physical or 
biological features defined in paragraph (2) of this entry. We used the 
digital landcover layer for St. Thomas created by the National 
Oceanographic and Atmospheric Administration 2012 Coastal Change 
Analysis Program 30m land cover dataset over color infrared imagery 
provided by the United States Army Corps of Engineers. The resulting 
critical habitat unit was then mapped using Contiguous Albers North 
American Datum 83 coordinates. The map in this entry, as modified by 
any accompanying regulatory text, establishes the boundaries of the 
critical habitat designation.
    (5) Unit LVIS-1: Hans Lollik Island, United States Virgin Islands.
    (i) Unit LVIS-1 consists of the entire Hans Lollik Island (477 (193 
ha)), approximately 2 miles (3 km) north from the north-central coast 
of St. Thomas, United States Virgin Islands. Hans Lollik is a private 
island managed by Wild Ecology Group for conservation on behalf of its 
owners.
    (ii) Map of Unit LVIS-1 follows:

Figure 1 to Lesser Virgin Islands Skink (Spondylurus semitaeniatus) 
paragraph (5)(ii)

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Puerto Rican Skink (Spondylurus nitidus)
    (1) Critical habitat units are depicted for Desecheo Island and 
Puerto Rico, on the maps in this entry.
    (2) Within these areas, the physical or biological features 
essential to the conservation of the Puerto Rican skink consist of the 
following components:
    (i) Forest and shrub/scrub habitat types below 500 m (0.31 mi) 
elevation on mainland Puerto Rico and on Desecheo Island.
    (ii) Sufficient, appropriate ground cover (including, but not 
limited to leaf litter, rocks, and vegetative debris) for protection 
from predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
    (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 the final rule.
    (4) Data layers defining map units were created by delineating 
habitats that contain at least one or more of the physical or 
biological features defined in paragraph (2) of this entry. We used the 
digital landcover layer for Puerto Rico created by the National 
Oceanographic and Atmospheric Administration 2010 Coastal Change 
Analysis Program 30m land cover dataset over color infrared imagery 
provided by the United States Army Corps of Engineers. The resulting 
critical habitat units were then mapped using Contiguous Albers North 
American Datum 83 coordinates. The maps in this entry, as modified by 
any accompanying regulatory text, establish the boundaries of the 
critical habitat designation.
    (5) Index map follows:

Figure 1 to Puerto Rican skink (Spondylurus nitidus) paragraph (5)

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[GRAPHIC] [TIFF OMITTED] TP19DE24.007

    (6) Unit PR-1: Quebradillas; Municipalities of Camuy, Isabela, 
Quebradillas, Moca, and San Sebastian, Puerto Rico.
    (i) Unit PR-1 consists of 37,093 ac (15,011 ha) located in 
northwestern Puerto Rico. This unit is bounded by selected Puerto Rican 
GAP hexagons that contain forested areas along its northern boundary 
within the Municipalities (east to west) of Camuy, Quebradillas, 
Isabela, and Moca, and moving south towards San Sebast[iacute]an, and 
east back to Camuy. Most of this unit, 94 percent (34,711 ac), is 
composed of private land, while 6 percent (2,382 ac) is public and 
managed for conservation as the Guajataca Commonwealth Forest and the 
Lago Guajataca Wildlife Refuge. Approximately 2 percent of the private 
areas are also managed for conservation by Para La Naturaleza, Puerto 
Rico Conservation Trust, as the Montadero, Los Garc[iacute]a, and Terra 
Firme Natural Protected Areas.
    (ii) Map of Unit PR-1 follows:

Figure 2 to Puerto Rican skink (Spondylurus nitidus) paragraph (6)(ii)

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    (7) Unit PR-2: Florida; Municipalities of Arecibo, Barceloneta, 
Manati, Florida, Utuado, and Ciales, Puerto Rico.
    (i) Unit PR-2 consists of 32,752 ac (13,254 ha) located in north-
central Puerto Rico. This unit is bounded by selected Puerto Rico GAP 
hexagons that contain forested areas along its northern boundary within 
the Municipalities (east to west) of Manat[iacute], Barceloneta, and 
Arecibo, and moving south towards Utuado and Ciales, and east back to 
Manat[iacute]. Most of this unit, 97 percent (31,841 ac), is composed 
of private land, while 3 percent (911 ac) is public and managed for 
conservation as the Cambalache Commonwealth Forest. Approximately 6 
percent (1,851 ac) of the private areas are also managed for 
conservation by Para La Naturaleza as part of the R[iacute]o Encantado 
Natural Protected Area. Less than 1 percent (89 ac) is managed by the 
USDA as the Manat[iacute] Research Area.
    (ii) Map of Unit PR-2 follows:

Figure 3 to Puerto Rican skink (Spondylurus nitidus) paragraph (7)(ii)

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    (8) Unit PR-3: Southwest; Municipalities of Lajas, San German, 
Sabana Grande, Maricao, Mayaguez, Las Marias, and Yauco, Puerto Rico.
    (i) Unit PR-3 consists of 51,697 ac (20,921 ha) located in 
southwestern Puerto Rico. This unit is bounded by selected Puerto Rico 
GAP hexagons that contain forested areas along its northern boundary 
within the Municipalities (east to west) of Yauco, Maricao, Las 
Mar[iacute]as, Mayag[uuml]ez, and San Germ[aacute]n, and moving south 
towards Cabo Rojo, Lajas, and Sabana Grande, and east back to Yauco. 
Most of this unit, 87 percent (44,784 ac), is composed of private land, 
while 13 percent (6,913 ac) is public and managed for conservation as 
the Maricao and Sus[uacute]a Commonwealth Forests. Approximately 1 
percent (394 ac) of the private areas are also managed for conservation 
by Para La Naturaleza as part of the R[iacute]o Maricao Natural 
Protected Area.
    (ii) Map of Unit PR-3 follows:

Figure 4 to Puerto Rican skink (Spondylurus nitidus) paragraph (8)(ii)

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    (9) Unit PR-4: Ponce; Municipalities of Ponce, Juana D[iacute]az, 
and Villalba, Puerto Rico.
    (i) Unit PR-4 consists of 22,050 ac (8,923 ha) located in south-
central Puerto Rico. This unit is bounded by selected Puerto Rico GAP 
hexagons that contain forested areas across its northern and southern 
boundary within the Municipalities (east to west) of Villalba, Juana 
D[iacute]az, and Ponce. This proposed critical habitat includes all 
forested habitat within this boundary and does not include developed 
areas. Most of this unit, 99 percent (21,855 ac), is composed of 
private land, while approximately 1 percent (195 ac) is public and 
managed for conservation as the Cerrillos and Toro Negro Commonwealth 
Forests. Less than 1 percent (86 ac) of a private area known as the 
Picaflor Conservation Easement is managed by Para La Naturaleza.
    (ii) Map of Unit PR-4 follows:

Figure 5 to Puerto Rican skink (Spondylurus nitidus) paragraph (9)(ii)

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    (10) Unit PR-5: Desecheo Island, Puerto Rico.
    (i) Unit PR-5 consists of the entire Desecheo Island (355 ac (144 
ha)) in the Mona Passage, approximately 13 miles (21 km) from the 
closest point off the west coast of Puerto Rico. Desecheo Island is 
managed for conservation as a National Wildlife Refuge.
    (ii) Map of Unit PR-5 follows:

Figure 6 to Puerto Rican skink (Spondylurus nitidus) paragraph (10)(ii)

[[Page 103988]]

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Virgin Islands Bronze Skink (Spondylurus sloanii)
    (1) Critical habitat units are depicted for Water Island, Buck 
Island, and Turtledove Cay, U.S. Virgin Islands, on the maps in this 
entry.
    (2) Within these areas, the physical or biological features 
essential to the conservation of the Virgin Islands bronze skink 
consist of the following components:
    (i) Forest, shrub/scrub, and herbaceous habitat types on Buck 
Island, Turtledove Cay, and Water Island, USVI.
    (ii) Sufficient, appropriate ground cover (including, but not 
limited to leaf litter, rocks, and vegetative debris) for protection 
from predators, refugia from temperature extremes, sources of food, and 
areas for reproduction.
    (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 the final rule.
    (4) Data layers defining map units were created by delineating 
habitats that contain at least one or more of the physical or 
biological features defined in paragraph (2) of this entry. We used the 
digital landcover layer for St. Thomas created by the National 
Oceanographic and Atmospheric Administration 2012 Coastal Change 
Analysis Program 30m land cover dataset over color infrared imagery 
provided by the United States Army Corps of Engineers. The resulting 
critical habitat units were then mapped using Contiguous Albers North 
American Datum 83 coordinates. The maps in this entry, as modified by 
any accompanying regulatory text, establish the boundaries of the 
critical habitat designation.
    (5) Unit VIBS-1: Water Island, United States Virgin Islands.
    (i) Unit VIBS-1 consists of 340 ac (138 ha) of Water Island, less 
than 1 mile (1.6 km) south from the south-central coast of St. Thomas, 
United States Virgin Islands, and less than 1 mile (1.6 km) west of 
Hassel Island. Most of this unit, approximately 73 percent (247 ac (100 
ha)), is composed of private land, of which approximately 12 percent 
(30 ac (12 ha)) is managed for conservation by The Nature Conservancy. 
Approximately 93 acres (38 ha) are owned by the Territorial Government.
    (ii) Map of Unit VIBS-1 is at paragraph (7)(ii) of this entry.
    (6) Unit VIBS-2: Buck Island, United States Virgin Islands.
    (i) Unit VIBS-2 consists of the entire Buck Island (48 ac (19 ha)), 
approximately 2 miles (2 km) south from the southeastern coast of St. 
Thomas, United States Virgin Islands, and just west of Capella Island. 
Buck Island is managed for conservation as the Buck Island National 
Wildlife Refuge.
    (ii) Map of Unit VIBS-2 is at paragraph (7)(ii) of this entry.
    (7) Unit VIBS-3: Turtledove Cay, United States Virgin Islands.
    (i) Unit VIBS-3 consists of the entire Turtledove Cay (4 ac (2 
ha)), also locally known as Little Saba, approximately 3 miles (4.8 km) 
south from the southwestern coast of St. Thomas, United States Virgin 
Islands, and approximately 3 miles west from the southern coast of 
Water Island (Unit VIBS-1). Turtledove Cay is owned by the Territorial 
Government.
    (ii) Map of Unit VIBS-1, Unit VIBS-2, and Unit VIBS-3 follows:

Figure 1 to Virgin Islands Bronze Skink (Spondylurus sloanii) paragraph 
(7)(ii)

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* * * * *

Martha Williams,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2024-29125 Filed 12-18-24; 8:45 am]
BILLING CODE 4333-15-P`