103938 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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. 

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/caribbeanecological-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, Boquero ́n, PR 00622; 

telephone 352–749–2462; email: 

lourdes_mena@fws.gov. 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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103940 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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-directorsmemo-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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103941 

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 


lotter on DSK11XQN23PROD with PROPOSALS2
103942 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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). 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.000</GPH>

Desecheo 

0 0.5 1 Kilometers 

Mona 

0 20 

0 15 

Desecheo 

Mona skink 

Puerto Rican skink 

Culebra skink 

A 

40 80 Kilometers 

30 60 Miles 

Mainland Puerto Rico 

.. 

Cayo Lobito ..--

_ _.. Cayo Del Agua 

' Cayo Luis Pena 

0 1.5 3 6 KIiometers 

Cayo lcacos 

0 0.5 1 Kilometers 

3⁄4 

Cayo 

/sotella 

Culebrita 

Figure 1. Distribution map for Puerto Rican skink, Mona skink, and Culebra skink. 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103943 

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). 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.001</GPH>

Turtledove Cay 

----.. 

6 0.5 1Kllt'l!i'Wters 0.5 . 

little Tobago-.., .D 

2 

Capella 

t 

~11 

1 Kilometers 

Little Thatch 

i "'---Hanslollik 

z, 

Turtl 

--[II 

Water Island 2 

.,,..~ 

Buck Island Capella 

St. John 

i888i Greater Virgin Islands sldnk 

Necker Island 

Great Camanoe i 

IP' 

Guana Island . t 

~,.~ 

-~~ 

,, 

h -"t ''\ Fallen Jerusalem 

~'t,; • '\ Round Rock 

\ Ginger Island 

• ri '\ Salt Island 

t Peter Island 

Norman Island ~-S-al-t -

1

s-la_n_d ___ ~ 

!Z:ZI Greater Virgin Islands skink; Lesser Virgin Islands skink; Vlrgih Islands bronze skink 

111111 Lesser Virgin Islands skink 

0 0.5 1 ·Kilometer$ 

LJ...w...J 

Lesser Virgin Islands skink; Virgin Islands bronze skink 

- Virgin Islands bronze skink 0 5 10 20 Kilometers N 

0 3,5 7 14Milas A 

Figure 2. Distribution map for Greater Virgin Islands skink, Lesser Virgin Islands skink, 

and Virgin Islands bronze skink. 
103944 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.002</GPH>

Green Cay 

I 

0.25 0.5 Kilometers 

-GrealerSt. Ctoixskink: 

!ll!ll!!ll Greater St. Croix skink; lesser St: Citii>t skink 

0. 3 e. 12 Kilame\in. N 

0 2.5 5 10Miles A 

Figure 3. Distribution map for Greater Saint Croix skink and Lesser Saint Croix skink. 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103945 

of the Interior, Office of the Solicitor 

(M–37021, January 16, 2009; ‘‘MOpinion,’’ available online at https://

www.doi.gov/sites/doi.opengov

.ibmcloud.com/files/uploads/M37021.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. Longterm 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103946 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 (Lo ́pez– 

Torres and Garcı ́a 2013, entire) and the 

Puerto Rican skink (Gonza ́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 bluetailed 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 

(Martı ́n and Lo ́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, 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 

(Dı ́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 highquality 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 (Garcı ́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 km2) 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103948 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

(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 cooccurring 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 (km2) (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 km2 (500 ha); therefore, we 

did not try to estimate status of 

populations on larger islands and 

considered all islands >5 km2 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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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

Score 

Habitat metrics 

Habitat protection Nonnative predator 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-Rolo ́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, 


lotter on DSK11XQN23PROD with PROPOSALS2
103950 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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

Score 

Habitat metrics 

Habitat protection Nonnative predator pressure Sea level rise (SLR) Storm surge 

¥1 .................... Low ........................ High (extirpation likely on islands 

<15 ha).

High: >25% inundated from SLR 

or SLR + storm surge.

High: >25% inundated from SLR 

+ storm surge. 

0 ........................ Moderate ............... Low ............................................. Moderate or Low: <25% inundated from SLR or SLR + 

storm surge.

Moderate or Low: >10% but 

<25% inundated from 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

Scenario Habitat protection Nonnative predator pressure Sea level rise (SLR) + 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 

Bayamo ́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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 Pen ̃ 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 Conservacio ́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 Germa ́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. 


lotter on DSK11XQN23PROD with PROPOSALS2
103952 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

TABLE 4—PUERTO RICAN SKINK CURRENT RESILIENCY SUMMARY—Continued 

[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 

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. 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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.] 

Population 

Current 2050 2070 2100 

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 


lotter on DSK11XQN23PROD with PROPOSALS2

I I I I I I I I I I I I 
103954 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103955 

TABLE 9—LESSER VIRGIN ISLANDS SKINK CURRENT RESILIENCY SUMMARY—Continued 

[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 

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 lowresiliency 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103956 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 km2 (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. 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103958 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103960 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 lowresiliency 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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103962 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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/endangeredspecies) 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/financialassistance. 

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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 speciesspecific 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103964 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 otherwiseprohibited 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. 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 livecapturing 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103966 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 lifehistory 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 lifehistory 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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 peerreviewed 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103968 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 nonU.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.] 

Critical habitat unit Land ownership by type 

Size of 

unit in acres 

(hectares) 

Occupied? 

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 Pen ̃ 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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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.] 

Critical habitat unit Land ownership by type 

Size of 

unit in acres 

(hectares) 

Occupied? 

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.] 

Critical habitat unit Land ownership by type 

Size of 

unit in 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 Agriculture ......................... 89 (36) Yes. 

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 


lotter on DSK11XQN23PROD with PROPOSALS2
103970 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

Moca, and moving south towards San 

Sebastı ́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 Garcı ́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 

Manatı ́, Barceloneta, and Arecibo, and 

moving south towards Utuado and 

Ciales, and east back to Manatı ́. 

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 Rı ́o 

Encantado Natural Protected Area. Less 

than 1 percent (89 ac) is managed by the 

USDA as the Manatı ́ 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 Marı ́as, Mayagu ̈ ez, 

and San Germa ́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 Susu ́ a Commonwealth 

Forests. Approximately 1 percent (394 

ac) of the private areas is also managed 

for conservation by PLN as part of the 

Rı ́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 Dı ́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.] 

Critical habitat unit Land ownership by type 

Size of 

unit in acres 

(hectares) 

Occupied? 

VBIS–1 Water Island ....................................... U.S. Territorial Government ............................ 93 (38) Yes. 

Private .............................................................. 247 (100) 

VBIS–2 Buck Island ......................................... USFWS ............................................................ 48 (19) Yes. 

VBIS–3 Turtledove Cay ................................... U.S. Territorial Government ............................ 4 (2) Yes. 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103971 

TABLE 14—PROPOSED CRITICAL HABITAT UNITS FOR THE VIRGIN ISLANDS BRONZE SKINK—Continued 

[Area estimates reflect all land within critical habitat unit boundaries.] 

Critical habitat unit Land ownership by type 

Size of 

unit in acres 

(hectares) 

Occupied? 

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 southcentral 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103972 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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, 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 


lotter on DSK11XQN23PROD with PROPOSALS2
103974 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 homelandsecurity 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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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. 


lotter on DSK11XQN23PROD with PROPOSALS2
103976 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 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 speciesspecific 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 

■ 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. 

■ 2. In § 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: 

§ 17.11 Endangered and threatened 

wildlife. 

* * * * * 

(h) * * * 

Common name Scientific name Where listed Status Listing citations and applicable rules 

*******

REPTILES

* * * * * * * 

Skink, Culebra ......................... Spondylurus culebrae ........... Wherever found ...... T [Federal Register citation when published 

as a final rule]; 50 CFR 17.42(t); 4d 50 

CFR 17.95(c).CH

Skink, Lesser Virgin Islands .... Spondylurus semitaeniatus ... Wherever found ...... E [Federal Register 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

* * * * * * * 


lotter on DSK11XQN23PROD with PROPOSALS2
103978 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

■ 3. Amend § 17.42 by adding paragraph 

(t) to read as follows: 

§ 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 §§ 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 

§ 17.21(b) for endangered wildlife. 

(ii) Take, as set forth at § 17.21(c)(1) 

for endangered wildlife. 

(iii) Possession and other acts with 

unlawfully taken specimens, as set forth 

at § 17.21(d)(1) for endangered wildlife. 

(iv) Interstate or foreign commerce in 

the course of commercial activity, as set 

forth at § 17.21(e) for endangered 

wildlife. 

(v) Sale or offer for sale, as set forth 

at § 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 § 17.32. 

(ii) Take, as set forth at § 17.21(c)(2) 

through (c)(4) for endangered wildlife. 

(iii) Take, as set forth at § 17.31(b). 

(iv) Possess and engage in other acts 

with unlawfully taken wildlife, as set 

forth at § 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 § 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: 

§ 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) 


lotter on DSK11XQN23PROD with PROPOSALS2
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103979 

(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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.003</GPH>

Index Map: Culebra Skink Critical Habitat 

c,. 

... 

Unit CUL-5 Cayo Lobito 

J 

'f. 

Unit CUL--4 Cayo Yerba 

~ \ 

• 

ona cu,-o c,,.,,,,t~ ~ 

Unit CUL-2 Cayo Botella 

--~ 

- Critical Habitat 

Puerto Rico CJ Municipal Boundaries 

0 0.5 1 2. 3 4 

-==-=---===---Miles N 

-=--=:..---=====--- Knomeiers 0 2 4 6 8 A 
103980 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

(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 Pen ̃ 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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.004</GPH>

Critical Habitat for Culebra Skink, Unit CUL-1 Culebra and 

Unit CUL-2 Cayo Botella, Culebra Island, Puerto Rico 

Unit CUL-1 Culebra 

""' Jtt"' Unit CUL~2 Cayo Botella 

Puerto Rico 

~•··r.,_I 

~ 

-~ 

• Critical Habitat 

D Municipal Boundaries 

0 0.5 1 2 3 

•-•.::;;.llll-.:::: .. ===~ ... ~. Miles. 

•--==---=======----Kilomeierso 1 2 4 6 

N 

A 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103981 

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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.005</GPH>

Critical Habitat for Culebra Skink, Unit CUL-3 Cayo del Agua, 

Unit CUL-4 Cayo Yerba, and Unit CUL-5 Cayo Lobito, 

Culebra Island, Puerto Rico 

., ._.... Unit CUL-5 Cayo Lobito 

Unit CUL-4 Cayo Verba 

' • 

" ? 

UnifCLJi>-3 Cayo del Agua 

• Critical Habitat 

Puerto Rico D Municipal Boundaries 

. ";-

.. , ~ 0 0.3 0.6 12 . 1.8 2.4 

Miles N 

- - Kilometers 

0 0.5 1 2 3 A 
103982 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.006</GPH>

Critical Habitat for the Lesser Virgin Island Skinkt Unit LVIS-1 Hans 

Lollik Island, Hans Lollik Island, USVI 

U.S. Virgin Islands 

St. Thomas st. John 

Unit LVJS-1 Hans Lollik Island 

st. Thomas 

- Critical Habitat 

D U.S. Virgin Islands Boundary 

0 0.5. 1 2 3 

•--=•--====---Miles 

•--=:::i--======----Kilorneters. 

0 1 2 4 6 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103983 

(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 Sebastı ́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 Garcı ́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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.007</GPH>

Index Map: Puerto Rican Skink Critical Habitat Units 

Unit PR-5 Desecheo 

Mona Passage 

Puerto Rico 11\l!! Critical Habitat 

D Municipal Boundaries 

0 

0 5 10 20 30 

- - Miles 

-- Kilometers 

0 5 10 20 30 

N 

A 
103984 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

(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 Manatı ́, Barceloneta, 

and Arecibo, and moving south towards 

Utuado and Ciales, and east back to 

Manatı ́. 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 Rı ́o Encantado Natural 

Protected Area. Less than 1 percent (89 

ac) is managed by the USDA as the 

Manatı ́ Research Area. 

(ii) Map of Unit PR–2 follows: 

Figure 3 to Puerto Rican skink 

(Spondylurus nitidus) paragraph 

(7)(ii) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.008</GPH>

Critical Habitat for Puerto Rican Skink, Unit PR-1 Quebradillas, Municipalities of 

Camuy, lsabela, Quebradillas, Moca, and San Sebastian, Puerto Rico 

Puerto Rico - Critical Habitat 

D Municipal Boundaries 

·oc 2 4 6 B 

Miles N 

0 1:5 3 6 9 12 

Kilometers A 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103985 

(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 

Marı ́as, Mayagu ̈ ez, and San Germa ́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 Susu ́ 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 Rı ́o Maricao Natural 

Protected Area. 

(ii) Map of Unit PR–3 follows: 

Figure 4 to Puerto Rican skink 

(Spondylurus nitidus) paragraph 

(8)(ii) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.009</GPH>

Critical Habitat for Puerto Rican Skink, Unit PR-2 Florida, Municipalities of 

Arecibo, Barceloneta, Manati, Florida, Utuado, and Ciales, Puerto Rico 

Vega Baja 

Areclbo 

- Critical Habitat 

'Pi.ierto Rico CJ Municipal Boundarles 

~ f t -~ -~ -~ ••c····::::iwiii··-c·· ::J· liiiiiliiiii-==::::::=:::::::liii•--Miles 

-==-c:::11---======i--•Kilometers 

0 1.5 3 6 9 12 

N 

A 
103986 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

(9) Unit PR–4: Ponce; Municipalities 

of Ponce, Juana Dı ́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 Dı ́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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.010</GPH>

Critical Habitat for Puerto Rican Skink, Unit PR-3 Southwest, Municipalities of 

Lajas, San German, Sabana Grande, Maricao, Mayaguez, Las Marias, and 

Yauco, Puerto Rico 

Mona Passage 

Puerto Rico 

Las Marlas 

Mayaguez 

0 1 2 8 

-=-=:i--===--•Miles 

4 6 

• Critical Habitat 

D Municipal Boundaries 

N 

0 2 4 

MCllMIC::J---====---Kilometers 

8 12 16 A 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103987 

(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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.011</GPH>

Critical Habitat for Puerto Rican Skink, Unit PR-4 Ponce, 

Municipalities of Ponce, Juana Diaz, and Villalba, Puerto Rico 

- Critical Habitat Puerto Rico D Municipal Boundaries 

0 0.5 1 2 3 4 

IClEl--===--Mlles N 

••.-;:;· .:JIWIC;;I. --c:::=::::w-wKilometers 

0 1 2 4 6 8 A 
103988 Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 

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) 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.012</GPH>

Critical Habitat for Puerto Rican Skink, Unit PR-5 Desecheo, 

Desecheo Island, Puerto Rico 

Desecheo Island 

Mona Passage 

Puerto Rico 

Ill Critical Habitat 

D Municipal Boundaries 

0 1 2 4 6 8 

-- Miles N 

Kilometers 

0 1.5 3 6 9 12 A 
Federal Register / Vol. 89, No. 244 / Thursday, December 19, 2024 / Proposed Rules 103989 

* * * * * 

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 


lotter on DSK11XQN23PROD with PROPOSALS2EP19DE24.013</GPH>

Critical Habitat for Virgin Island Bronze Skink, Unit VIBS-1 Water 

Island, Unit VIBS-2 Buck Island, and Unit VIBS-3 Turtledove Cay, 

U.S. Virgin Islands 

Uhlt VIBS..:.3Turtledove Cay \.t n· 

•· D 

U.S. Virgin Islands 

:~· t~ #'. 

•• --~ ·-~-~-

.. ~ • st. John. 

St. Thomas 

St. Thomas 

. . 

t 

Uiiif VIBS.: f Watar Island 

Un,t VlBS-:2 Buck Island. 

' ........ -. --T'""C]. 

• Critical Habitat 

D U.S. Virgin Islands Boundary 

o•--=o=.5•-•1===-2 --3Miles 

•--=:::::i--. ===::::::;:JI ___ Kilometers 

0 1 2 4 6 

N 

A