Endangered and Threatened Wildlife and Plants; Reclassifying the Virgin Islands Tree Boa From Endangered to Threatened With a Section 4(d) Rule, 61700-61717 [2020-19027]
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Federal Register / Vol. 85, No. 190 / Wednesday, September 30, 2020 / Proposed Rules
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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
§ 17.61(b).
(ii) Remove and reduce to possession
from areas under Federal jurisdiction, as
set forth at § 17.61(c)(1).
(iii) Maliciously damage or destroy
the species on any areas under Federal
jurisdiction, or remove, cut, dig up, or
damage or destroy the species on any
other area in knowing violation of any
State law or regulation or in the course
of any violation of a State criminal
trespass law, as set forth at section
9(a)(2)(B) of the Act.
(iv) Interstate or foreign commerce in
the course of commercial activity, as set
forth at § 17.61(d).
(v) Sell or offer for sale, as set forth
at § 17.61(e).
(2) Exceptions from prohibitions. The
following exceptions from prohibitions
apply to beach layia:
(i) The prohibitions described in
paragraph (b)(1) of this section do not
apply to activities conducted as
authorized by a permit issued in
accordance with the provisions set forth
at § 17.72.
(ii) Any employee or agent of the
Service or of a State conservation
agency that is operating a conservation
program pursuant to the terms of a
cooperative agreement with the Service
in accordance with section 6(c) of the
Act, who is designated by that agency
for such purposes, may, when acting in
the course of official duties, remove and
reduce to possession from areas under
Federal jurisdiction members of beach
layia that are covered by an approved
cooperative agreement to carry out
conservation programs.
(iii) You may engage in any act
prohibited under paragraph (b)(1) of this
section with seeds of cultivated
specimens, provided that a statement
that the seeds are of ‘‘cultivated origin’’
accompanies the seeds or their
container.
Aurelia Skipwith,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2020–19026 Filed 9–29–20; 8:45 am]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS–R4–ES–2019–0069;
FXES11130900000–189–FF0932000]
RIN 1018–BE14
Endangered and Threatened Wildlife
and Plants; Reclassifying the Virgin
Islands Tree Boa From Endangered to
Threatened With a Section 4(d) Rule
Fish and Wildlife Service,
Interior.
ACTION: Proposed rule.
AGENCY:
We, the U.S. Fish and
Wildlife Service (Service), propose to
reclassify the Virgin Islands tree boa
(Virgin Islands boa; Chilabothrus (=
Epicrates) granti) from an endangered
species to a threatened species with a
rule issued under section 4(d) of the
Endangered Species Act of 1973 (Act),
as amended. If we finalize this rule as
proposed, it would reclassify the Virgin
Islands boa from endangered to
threatened on the List of Endangered
and Threatened Wildlife (List). This
proposal is based on a thorough review
of the best available scientific data,
which indicate that the species’ status
has improved such that it is not
currently in danger of extinction
throughout all or a significant portion of
its range. We are also proposing a rule
under the authority of section 4(d) of the
Act that provides measures that are
necessary and advisable to provide for
the conservation of the Virgin Islands
boa. Further, we are correcting the List
to change the scientific name of the
Virgin Islands boa in the List from
Epicrates monensis granti to
Chilabothrus granti to reflect the
currently accepted taxonomy. Virgin
Islands boa is a distinct species, not a
subspecies, and Epicrates is no longer
the scientifically accepted genus for this
species.
DATES: We will accept comments
received or postmarked on or before
November 30, 2020. Comments
submitted electronically using the
Federal eRulemaking Portal (see
ADDRESSES, below) must be received by
11:59 p.m. Eastern Time on the closing
date. We must receive requests for a
public hearing, in writing, at the address
shown in FOR FURTHER INFORMATION
CONTACT by November 16, 2020.
ADDRESSES: Written comments: You may
submit comments on this proposed rule
by one of the following methods:
(1) Electronically: Go to the Federal
eRulemaking Portal: https://
SUMMARY:
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www.regulations.gov. In the Search box,
enter FWS–R4–ES–2019–0069, which is
the docket number for this rulemaking.
Then, click on the Search button. On the
resulting page, in the Search panel on
the left side of the screen, under the
Document Type heading, click on the
Proposed Rule box to locate this
document. You may submit a comment
by clicking on ‘‘Comment Now!’’
(2) By hard copy: Submit by U.S. mail
to: Public Comments Processing, Attn:
FWS–R4–ES–2019–0069; U.S. Fish and
Wildlife Service, MS: JAO/1N, 5275
Leesburg Pike, Falls Church, VA 22041–
3803.
We request that you send comments
only by the methods described above.
We will post all comments on https://
www.regulations.gov. This generally
means that we will post any personal
information you provide us (see
Information Requested, below, for more
information).
Document availability: The proposed
rule and supporting documents
(including the species status assessment
(SSA) report and references cited) are
available at https://www.regulations.gov
under Docket No. FWS–R4–ES–2019–
0069.
FOR FURTHER INFORMATION CONTACT:
Edwin E. Mun˜iz, Field Supervisor, U.S.
Fish and Wildlife Service, Caribbean
Ecological Services Field Office, Road
301 Km 5.1, Corozo Ward, Boquero´n,
Puerto Rico 00622; or P.O. Box 491,
Boquero´n, Puerto Rico 00622; telephone
787–851–7297. Persons who use a
telecommunications device for the deaf
(TDD) may call the Federal Relay
Service at 800–877–8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under
the Act, a species may warrant
reclassification from endangered to
threatened if it no longer meets the
definition of endangered (in danger of
extinction). The Virgin Islands boa is
listed as endangered, and we are
proposing to reclassify it as threatened
because we have determined it is no
longer in danger of extinction.
Reclassifications can only be made by
issuing a rule. Furthermore, extending
the ‘‘take’’ prohibitions in section 9 of
the Act to threatened species, such as
those we are proposing for this species
under a section 4(d) rule, can only be
made by issuing a rule. Finally, the
change of the scientific name of the
Virgin Islands boa in the List from
Epicrates monensis granti to
Chilabothrus granti, can only be made
effective by issuing a rule.
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Federal Register / Vol. 85, No. 190 / Wednesday, September 30, 2020 / Proposed Rules
What this rule does. We propose to
reclassify the Virgin Islands tree boa
from an endangered species to a
threatened species with a rule issued
under section 4(d) of the Act to provide
measures that are necessary and
advisable to provide for the
conservation of this species. We also
change the scientific name in the List to
reflect the currently accepted taxonomy.
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
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 Virgin Islands
boa is not currently in danger of
extinction and, therefore, does not meet
the definition of an endangered species,
but is still affected by the following
current and ongoing stressors to the
extent that the species meets the
definition of a threatened species under
the Act:
• Habitat loss and fragmentation from
human development (Factor A).
• Direct and indirect predation/
competition by exotic mammals such as
rats, cats, and possibly, to a lesser
extent, mongoose (Factor C).
• Stochastic events such as
hurricanes and sea level rise,
exacerbated by the cumulative effects of
climate change (Factor E).
• Intentional harm due to fear of
snakes (Factor E).
We are also proposing a section 4(d)
rule. When we list a species as
threatened, section 4(d) of the Act
allows us to issue regulations that are
necessary and advisable to provide for
the conservation of the species.
Accordingly, we are proposing a 4(d)
rule for the Virgin Islands boa that
would, among other things, prohibit
take associated with capturing,
handling, trapping, collecting, or other
activities, including intentional or
incidental introduction of exotic
species, such as cats or rats that
compete with, prey upon, or destroy the
habitat of the Virgin Islands boa. The
proposed 4(d) rule would also except
from these prohibitions take associated
with certain conservation efforts.
Peer review. In accordance with our
joint policy on peer review published in
the Federal Register on July 1, 1994 (59
FR 34270), and our August 22, 2016,
memorandum updating and clarifying
the role of peer review of listing actions
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under the Act, we sought the expert
opinions of six appropriate specialists
regarding the species status assessment
report (SSA). We received responses
from five specialists on the SSA report,
which informed this proposed rule. The
purpose of peer review is to ensure that
our listing determinations, critical
habitat designations, and 4(d) rules are
based on scientifically sound data,
assumptions, and analyses. The peer
reviewers have expertise in the biology,
habitat, and threats to the species.
Because we will consider all
comments and information we receive
during the comment period, our final
determination may differ from this
proposal. Based on the new information
we receive (and any comments on that
new information), we may conclude that
the species is endangered instead of
threatened, or we may conclude that the
species does not warrant listing as either
an endangered species or a threatened
species. Such final decisions would be
a logical outgrowth of this proposal, as
long as we: (1) Base the decisions on the
best scientific and commercial data
available, after considering all of the
relevant factors; (2) do not rely on
factors Congress has not intended us to
consider; and (3) articulate a rational
connection between the facts found and
the conclusions made, including why
we changed our conclusion.
Information Requested
We intend that any final action
resulting from this 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 and
information from other concerned
governmental agencies, Native
American tribes, the scientific
community, industry, or any other
interested party concerning this
proposed rule.
We particularly seek comments on:
(1) Information concerning the
biology and ecology of the Virgin
Islands boa.
(2) Relevant data concerning any
stressors (or lack thereof) to the Virgin
Islands boa, particularly any data on the
possible effects of climate change as it
relates to habitat, and the extent of
Territorial protection and management
that would be provided to this boa as a
threatened species.
(3) Reasons why we should or should
not reclassify the Virgin Islands boa
from an endangered species to a
threatened species under the Act.
(4) Information concerning activities
that should be considered under a rule
issued in accordance with section 4(d)
of the Act (16 U.S.C. 1531 et seq.) as a
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prohibition or exception within U.S.
territory that would contribute to the
conservation of the species. In
particular, we are seeking input from
experts regarding species restoration
and captive propagation practices and
related activities, or whether take
associated with any other activities
should be considered excepted from the
prohibitions in the 4(d) rule.
(5) Current or planned activities
within the geographic range of the
Virgin Islands boa that may either
negatively impact or benefit the species.
Please include sufficient information
with your submission (such as scientific
journal articles or other publications) to
allow us to verify any scientific or
commercial information you include.
Please note that submissions merely
stating support for, or opposition to, the
action under consideration without
providing supporting information,
although noted, will not be considered
in making a determination, as section
4(b)(1)(A) of the Act directs that
determinations as to whether any
species is an endangered or a threatened
species must be made ‘‘solely on the
basis of the best scientific and
commercial data available.’’
You may submit your comments and
materials concerning this proposed rule
by one of the methods listed in
ADDRESSES. We request that you send
comments only by the methods
described in ADDRESSES.
If you submit information via https://
www.regulations.gov, your entire
submission—including any personal
identifying information—will be posted
on the website. If your submission is
made via a hardcopy that includes
personal identifying information, you
may request at the top of your document
that we withhold this information from
public review. However, we cannot
guarantee that we will be able to do so.
We will post all hardcopy submissions
on 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, or by
appointment, during normal business
hours, at the U.S. Fish and Wildlife
Service, Caribbean Ecological Services
Field Office (see FOR FURTHER
INFORMATION CONTACT).
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
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Federal Register / Vol. 85, No. 190 / Wednesday, September 30, 2020 / Proposed Rules
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 at least 15 days before
the hearing. For the immediate future,
we will provide these public hearings
using webinars that will be announced
on the Service’s website, in addition to
the Federal Register. The use of these
virtual public hearings is consistent
with our regulation at 50 CFR
424.16(c)(3).
Previous Federal Actions
The Virgin Islands boa was originally
listed as an endangered subspecies
(Epicrates inornatus granti) of the
Puerto Rican boa (Epicrates inornatus at
time of listing, now Chilabothrus
inornatus) on October 13, 1970 (35 FR
16047), under the Endangered Species
Conservation Act of 1969, and remained
listed with the passage of the Act in
1973. In 1979, we published a technical
correction (44 FR 70677, December 7,
1979) revising the scientific name of the
Virgin Islands boa from Epicrates
inornatus granti to Epicrates monensis
granti. A recovery plan for this species
was completed in 1986 (Service 1986,
entire) and updated in September 2019.
The most recent 5-year review,
completed in 2009, recommended
reclassifying the Virgin Islands boa to a
threatened species due to the
population stabilizing (Service 2009,
entire). Based on this recommendation,
we initiated a species status assessment
(SSA) and completed an SSA report in
2018 (Service 2018, entire).
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Supporting Documents
A species status assessment (SSA)
team prepared an SSA report for the
Virgin Islands boa. The SSA team was
composed of Service biologists, in
consultation with other species experts.
The SSA report represents a
compilation of the best scientific and
commercial data available concerning
the status of the species, including the
impacts of past, present, and future
factors (both negative and beneficial)
affecting the species. The Service sent
the SSA report to six independent peer
reviewers and received five responses.
The Service also sent the SSA report to
state partners, including scientists with
expertise in Virgin Islands boa habitat,
for review. We received review from
two experts from the Puerto Rico
Department of Natural and
Environmental Resources.
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I. Proposed Reclassification
Determination
Background
A thorough review of the taxonomy,
life history, ecology, and overall
viability of the Virgin Islands boa is
presented in the SSA report (Service
2018, entire; available at https://
www.fws.gov/southeast/ and at https://
www.regulations.gov under Docket No.
FWS–R4–ES–2019–0069). A summary
of this information follows:
The Virgin Islands boa is endemic to
Puerto Rico and the Virgin Islands (U.S.
and British). Originally, the Virgin
Islands boa was considered a subspecies
of the Puerto Rican boa (Epicrates
inornatus; Stull 1933, pp. 1–2), but was
later found to be more closely related to
the Mona Island boa, and the
nomenclature for the two snakes was
altered to reflect two subspecies,
Epicrates monensis monensis (Mona
Island boa) and E. m. granti (Virgin
Islands boa) (Sheplan and Schwartz
1974, pp. 94–104). More recently,
molecular phylogeny work indicates
that the genus Epicrates is paraphyletic
(a group composed of a collection of
organisms, including the most recent
common ancestor of all those
organisms), and the West Indian clade
(as opposed to the mainland clade) was
designated as Chilabothrus (Reynolds et
al. 2013, entire). As a result, the Virgin
Islands boa is now considered its own
species. We accept the change of the
Virgin Islands boa’s classification from
the subspecies Epicrates monensis
granti to the species Chilabothrus granti
and are amending the scientific name to
match the currently accepted
nomenclature.
The Virgin Islands boa is a mediumlength, slender, nonvenomous snake.
The largest snout-vent lengths (SVL)
recorded for the species were 1,066
millimeters (mm; 42 inches (in)) for
females and 1,112 mm (44 in) for males
(total body lengths 1,203 mm (47 in) and
1,349 mm (53 in), respectively; Tolson
2005, entire), although most specimens
range between 600 and 800 mm (24–31
in) SVL, with an average mass of 165
grams (6 ounces) (USVI Division of
Wildlife, unpub. data). Adults are graybrown with dark-brown blotches that
are partially edged with black, and
feature a blue-purple iridescence on
their dorsal surface; the ventral surface
is creamy white or yellowish white.
Newborns, on the other hand, have an
almost grayish-white body color with
black blotches and weigh 2.0–7.2 grams
(0.07–0.25 ounces) with SVLs of 200–
350 mm (approx. 8–14 inches) (Tolson
1992, pers. comm.).
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The Virgin Islands boa occurs in
subtropical dry forest and subtropical
moist forest (Service 2009, p. 11).
Subtropical dry forest covers
approximately 14 percent (128,420
hectares (ha); 317,332 acres (ac)) of
Puerto Rico and the U.S. Virgin Islands
(USVI), typically receives less than 750
mm (29 in) rainfall annually (Ewel and
Whitmore 1973, pp. 9–20), and is
characterized by small (less than 5
meter (m; 16 feet (ft)) deciduous trees
with high densities of interlocking
branches and vines connecting adjacent
tree canopies (Ewel and Whitmore 1973,
p. 10). Subtropical moist forest covers
approximately 58 percent (538,130 ha;
1,329,750 acres) of Puerto Rico and
USVI and typically receives more than
1,100 mm (43 in) of annual rainfall. It
is dominated by semi-evergreen and
evergreen deciduous trees up to 20 m
(66 ft) tall with rounded crowns. The
Virgin Islands boa has also been
reported to occur in mangrove forest,
thicket/scrub, disturbed lower
vegetation, and artificial structures
(Harvey and Platenberg 2009, p. 114;
Tolson 2003, entire).
Habitat needs for Virgin Islands boa
can be divided into those for foraging
and those for resting. Factors
contributing to foraging habitat quality
are tree density and connectivity,
presence of arboreal and ground-level
refugia, prey density, and rat presence/
density (Tolson 1988, pp. 234–235).
Tree density is more important than tree
species or diversity; Virgin Islands boas
do not appear to prefer a particular tree
species after accounting for availability
and structure (Platenberg 2018, pers.
comm.). The highest densities of Virgin
Islands boas are found where there are
few or no exotic predators and high
densities of lizard prey (Tolson 1988, p.
233; Tolson 1996b, p. 410). Resting
habitat includes refugia for inactive boas
to use during the day. Refugia can be the
axils (angles between trunk and
branches) of Cocos or Sabal species, tree
holes, termite nests, or under rocks and
debris (Tolson 1988, p. 233).
The Virgin Islands boa forages at night
by gliding slowly along small branches
in search of sleeping lizards (Service
1986, p. 6). The primary prey for the
Virgin Islands boa is the Puerto Rican
crested anole (Anolis cristatellus), and
the greatest concentrations of Virgin
Islands boa are found where Anolis
densities exceed 60 individuals/100 m2
(1,076 ft2; Tolson 1988, p. 233). Other
prey species include ground lizard
(Ameiva exsul), house mouse (Mus
musculus), small birds, iguana (Iguana
iguana) hatchlings, and likely other
small animals encountered (Maclean
1982, pp. 30–31, 37; Tolson 1989, p.
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165; Tolson 2005, p. 9; Platenberg 2018,
pers. comm.). The Virgin Islands boa
may also compete for prey and other
niche components with the Puerto
Rican racer (Borikenophis
portoricensis), a snake native to Puerto
Rico, the U.S. and British Virgin Islands,
and surrounding cays.
Much of what is known about Virgin
Islands boa life history comes from
studies in captivity. Lifespans in
captivity often exceed 20 years, and
sometimes exceed 30 years (7% of
captive Virgin Islands boas exceeded 30
years of age; Smith 2018, pers. comm.),
but typical lifespans in the wild are not
known. Sexual maturity is reached at 2–
3 years of age (Tolson 1989, Tolson and
Pin˜ero 1985), and boas are still
reproductive at >20 years of age (Tolson
2018, pers. comm.). Females breed
biennially, but studies have suggested
that annual breeding may occur in some
conditions (Tolson and Pin˜ero 1985).
Courtship behaviors and copulation
occur from February through May, and
interaction with conspecifics of the
opposite sex appears to be necessary for
reproductive cycling (Tolson 1989). The
gestation period, observed from a single
known copulation between two
individuals, is about 132 days (Tolson
1989). Virgin Islands boas give birth to
live young from late August through
October to litters of 2–10 young, and
litter size increases with female body
size (Tolson 1992, pers. comm.).
The exact historical distribution of the
Virgin Islands boa is unknown, but its
present disjointed distribution suggests
that it was once more widely distributed
across small islands within its range. In
the 1970s, when the Virgin Islands boa
was originally listed, its range was
identified as three islands: Puerto Rico
(no specific site), St. Thomas, USVI
(from a single record), and Tortola in the
British Virgin Islands (BVI) (from one
report) (44 FR 70677, December 7,
1979). When the recovery plan was
written (1986), 71 individuals were
reported in two populations: one on the
eastern side of St. Thomas in the USVI,
and one at Cayo Diablo, an offshore islet
in Puerto Rico (Service 2009).
Currently, the Virgin Islands boa
occurs on six islands between Puerto
Rico, USVI, and BVI: the eastern Puerto
Rican islands of Cayo Diablo and
Culebra; Rı´o Grande on the Puerto Rican
main island; eastern St. Thomas and an
offshore cay in USVI (USVI Cay; an
introduced population); and Tortola. A
seventh population (also introduced) on
the Puerto Rican island of Cayo Ratones
may still remain, although after the
reestablishment of rats on this island
after 2004, the status of this population
is uncertain (Service 2018, p. 24). A
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recent survey did not find Virgin Islands
boas on Cayo Ratones in 2018 (Island
Conservation 2018, pp. 5, 17). However,
because Virgin Islands boas are difficult
to find, and the 2018 surveys were not
extensive (e.g., did not survey the whole
island), there is currently not enough
evidence to conclude the Cayo Ratones
population has been extirpated. Lastly,
there is also one report from 2004 that
the species occurs on Greater St. James
Island in St. Thomas, but nothing is
known about that potential population
(Dempsey 2019, pers. comm.). In 2009,
based on all known populations in
Puerto Rico and the USVI, an estimated
1,300–1,500 Virgin Islands boas were
thought to occur (Service 2009, p. 8),
although many population sizes used
for this estimate are highly speculative.
Based on the 2018 SSA (Service 2018,
entire), current population trend
estimates for Puerto Rico and USVI are
either declining, potentially declining,
considered rare, or unknown and most
populations are small or considered rare
(Service 2018, p. 30).
The population in Tortola Island, BVI,
was confirmed in 2018, but there are no
specific data regarding the status of that
population (McGowan 2018, pers.
comm.). In addition, according to
anecdotal reports, the species is thought
to occur on Jost Van Dyke, Guana
Island, Necker Cay, Great Camanoe, and
Virgin Gorda of the BVI (Mayer and
Lazell 1988, entire), but data and
confirmed observations are limited.
There is not enough information to
reliably assess the status of Virgin
Islands boa populations on those
islands.
Regulatory and Analytical Framework
Regulatory Framework
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 is an
‘‘endangered species’’ or a ‘‘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;
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(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
expected response by the species, 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 now and in the
foreseeable future.
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
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future on a case-by-case basis. The term
foreseeable future extends only so far
into the future as the Services can
reasonably determine that both the
future threats and the species’ responses
to those threats are likely. In other
words, the foreseeable future is the
period of time in which we can make
reliable predictions. ‘‘Reliable’’ does not
mean ‘‘certain’’; it means sufficient to
provide a reasonable degree of
confidence in the prediction. Thus, a
prediction is reliable if it is reasonable
to depend on it when making decisions.
It is not always possible or necessary
to define foreseeable future as a
particular number of years. Analysis of
the foreseeable future uses the best
scientific and commercial data available
and should consider the timeframes
applicable to the relevant threats and to
the species’ likely responses to those
threats in view of its life-history
characteristics. Data that are typically
relevant to assessing the species’
biological response include speciesspecific factors such as lifespan,
reproductive rates or productivity,
certain behaviors, and other
demographic factors.
redundant a species is and the more
representation it has, the more likely it
is to sustain populations over time, even
under changing environmental
conditions. 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. This process
used the best available information to
characterize viability as the ability of a
species to sustain populations in the
wild over time. We use this information
to inform our regulatory decision.
Analytical Framework
The SSA report documents the results
of our comprehensive biological status
review for the species, including an
assessment of the potential threats to the
species. The SSA report does not
represent a decision by the Service on
whether the species should be proposed
for listing as an endangered or
threatened species under the Act. It
does, however, 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. The following is a summary of
the key results and conclusions from the
SSA report; the full SSA report can be
found at Docket FWS–R4–ES–2019–
0069 on https://www.regulations.gov and
at https://www.fws.gov/southeast/.
To assess the Virgin Islands boa’s
viability, we used the three conservation
biology principles of resiliency,
redundancy, and representation (Shaffer
and Stein 2000, pp. 306–310). Briefly,
resiliency supports the ability of the
species to withstand environmental and
demographic stochasticity (for example,
wet or dry, warm or cold years),
redundancy supports the ability of the
species to withstand catastrophic events
(for example, droughts, large pollution
events), and representation supports the
ability of the species to adapt over time
to long-term changes in the environment
(for example, climate changes). In
general, the more resilient and
Summary of Biological Status and
Threats
In this discussion, we review the
biological condition of the species and
its resources, and the threats that
influence the species’ current and future
condition, in order to assess the species’
overall viability and the risks to that
viability. In the SSA report (Service
2018, pp. 12–18), we reviewed all
factors (i.e., threats, stressors) that could
be affecting the Virgin Islands boa now
or in the future. However, in this
proposed rule, we will focus our
discussion only on those factors that
could meaningfully impact the status of
the species. The risk factors affecting the
status of the Virgin Islands boa vary
from location to location, but generally
include habitat loss and degradation
from development, introduced
predators, sea level rise (SLR) and a
changing climate, and public attitudes
towards snakes. Where habitat is
available but the species is not present
(i.e., most of the small islands in the
eastern Puerto Rico bank and USVI), it
is believed that absences are due to local
extirpation resulting from habitat
degradation and colonization of exotic
species (Service 2009, p. 11). We
discuss each of the risk factors below.
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Development
Virgin Islands boas occur on both
privately and publicly owned land.
Virgin Islands boas have been observed
living in developed areas around
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residences and can persist within
developed areas if habitat patches are
available, but only if no cats or rats are
around (Platenberg and Harvey 2010, p.
552; Platenberg 2018, pers. comm.).
Where boas coexist with urban
development, development continues to
threaten populations via habitat
destruction, especially in St. Thomas,
Rı´o Grande (Puerto Rico), and Culebra
Island where habitat has declined
throughout decades. In St. Thomas,
available habitat has declined due to
development for resorts, condos, and
related infrastructure, and has become
more constricted and isolated
(Platenberg and Harvey 2010, p. 552). In
Puerto Rico, human populations are
decreasing, but residential development
continues to increase island-wide,
including around protected areas
(Castro-Prieto et al. 2017, entire).
Consequences of human development
on the boa and its habitat not only
include habitat loss and fragmentation
due to deforestation, but also mortality
from vehicular strikes, an increase in
predators such as cats and rats, and an
increase in human–boa conflicts that
results in snakes being killed because of
fear of snakes (Service 2018, pp. 13–14).
Both Puerto Rico and the USVI have
regulatory mechanisms established to
protect the species and its habitat
throughout consultation processes for
the authorization of development
projects. Presently, the Virgin Islands
boa is legally protected under Puerto
Rico’s Commonwealth Law No. 241–
1999 (12 L.P.R.A. Sec.107), known as
the New Wildlife Law of Puerto Rico.
This law has provisions to protect
habitat for all wildlife species, including
plants and animals. In addition, the
species is protected by Puerto Rico
Department of Natural and
Environmental Resources (PRDNER)’s
Regulation 6766, which under Article
2.06 prohibits collecting, cutting, and
removing, among other activities, listed
plant and animal individuals within the
jurisdiction of Puerto Rico (DRNA
2004). In USVI, Act No. 5665, known as
the Virgin Islands’ Indigenous and
Endangered Species Act, which is
enforced by the U.S. Virgin Islands
Department of Planning and Natural
Resources (VIDPNR), protects the
species.
Despite these regulations being in
place, including the requirement for
developers to conduct environmental
assessments and mitigate damage to the
species and habitat, the regulations have
proved difficult to enforce, they are
often ignored by developers, and they
do not cover all development activities
in all Virgin Islands boa habitat
(Platenberg 2011, pers. comm.). For
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example, in St. Thomas, major permit
applications submitted for projects in
the coastal zone require an
environmental impact assessment that
addresses endangered species and
protected habitat, but these
requirements do not apply to smaller
projects or those outside of the coastal
zone. Furthermore, as noted in one
study, even though a protocol was
developed and applied to delineate
habitat on protected sites and identify
mitigation strategies, the absence of a
legal mechanism to enforce mitigation
has led to varying success as developers
are slow to accept, and often ignore, the
mitigation process (Platenberg and
Harvey 2010, pp. 551–552).
Most offshore cays within the species’
range are part of the Territorial
Government or protected as wildlife
refuges, thus formally protecting Virgin
Islands boa habitat for three of the six
populations (i.e., Cayo Diablo, Cayo
Ratones, and USVI Cay). Cayo Ratones
and Cayo Diablo are included in La
Cordillera Natural Reserve managed by
the PRDNER, and the offshore cay in
USVI is managed and protected by the
VIDPNR. Furthermore, even though
Virgin Islands boa habitat on privately
owned land on Culebra Island is
currently under pressure from urban
and tourism development and
deforestation, more than 1,000 acres of
suitable habitat on the island are
protected within the Service’s Culebra
National Wildlife Refuge.
Predation and Competition
One of the primary threats to Virgin
Islands boa populations is predation by
exotic mammalian predators, mainly
cats and rats, and possibly, to a lesser
degree, mongoose. Mongoose are not
likely a major predator of Virgin Islands
boa because mongoose are terrestrial
and active during the day, while Virgin
Islands boas are arboreal and active
primarily at night, although not
exclusively (Service 2018, p. 14). Feral
cats are known to prey upon boas
(Tolson 1996b, p. 409), and cat
populations around human
development are further bolstered by cat
feeding stations set up by residents.
There has not been direct evidence of
rats preying upon Virgin Islands boas,
but boas are not present on islands with
high densities of rats (Tolson 1986,
unpaginated; Tolson 1988, p. 235). Rats
likely negatively impact Virgin Islands
boas by competing for prey, or by
inducing behavioral changes in Anolis
prey that make them less likely to be
encountered by boas (Tolson 1988, p.
235). However, rats may also predate on
neonate boas (Service 1986, p. 12).
Complete predator removal on large
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developed islands is challenging, but is
feasible on smaller cays. Prior to
reintroduction of the boas, rats were
eliminated from Cayo Ratones and the
USVI Cay using anticoagulant poison
(Tolson 1996b, p. 410), although Cayo
Ratones was recolonized by rats
sometime after August 2004,
highlighting the importance of ongoing
monitoring for rat presence after a
removal project. Cayo Ratones was
thought to harbor one of the most robust
Virgin Islands boa populations, but
during the recent 2018 survey, no boas
were found (Island Conservation 2018,
p. 20). There are no Virgin Islands boas
present on islands with established rat
populations and no rat predators (such
as cats).
Effects of Climate Change, Including
Sea Level Rise
Climate change will continue to
influence Virgin Islands boa persistence
into the future. Species that are
dependent on specialized habitat types
or limited in distribution (including the
Virgin Islands boa) are most susceptible
to the impacts of climate change (Byers
and Norris 2011, p. 22).
The climate in the southeastern
United States and Caribbean has
warmed about two degrees Fahrenheit
from a cool period in the 1960s and
1970s, and temperatures are expected to
continue to rise (Carter et al. 2014, pp.
398–399). Projections for future
precipitation trends in this area are less
certain than those for temperature, but
suggest that overall annual precipitation
will decrease, and that tropical storms
will occur less frequently but with more
force (i.e., more category 4 and 5
hurricanes) than historical averages
(Carter et al. 2014, pp. 398–399;
Knutson et al. 2010, pp. 161–162). With
increasing temperatures and decreasing
precipitation, drought could negatively
influence Virgin Islands boa
populations. After a severe drought in
eastern Puerto Rico, Anolis populations
crashed on Cayo Diablo and body
condition indices of the boas
plummeted (Tolson 2018, pers. comm.).
Sea levels are expected to rise
globally, potentially exceeding 1 m (3
feet) of SLR by 2100 (Reynolds et al.
2012, p. 3). Local SLR impacts will
depend not only on how much the
ocean level itself rises, but also on land
subsidence or changes in offshore
currents (Carter et al. 2014, p. 400).
Impacts on terrestrial ecosystems can be
temporary, via submergence of habitat
during storm surges, or permanent, via
salt water intrusion into the water table,
inundation of habitat, and erosion. SLR
and hurricane storm surges in the
Caribbean are predicted to inundate
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61705
low-lying islands and parts of larger
islands (Bellard et al. 2014, pp. 203–
204). The low-lying islands of Cayo
Diablo and the USVI Cay, which
support Virgin Islands boa populations,
and the island of Cayo Ratones, which
may still support a population, are all
vulnerable to SLR and storm surges in
the future. Boa populations on Rı´o
Grande, Culebra, and St. Thomas are not
considered at risk from SLR; however,
the three cays (Cayo Diablo, Cayo
Ratones, and USVI Cay) could see 10–
23 percent loss due to SLR over the next
30 years (Service 2018, pp. 38–46). Past
and current observations suggest that
the species can survive major hurricane
events, although lasting impacts to
habitat, particularly die-off of vegetation
inundated by storm surges, have been
observed (Platenberg 2018, pers. comm.;
Smith 2018, unpaginated; Tolson 1991,
pp. 12, 16; Yrigoyen 2018, pers. comm.).
Loss of habitat due to storm surge
impacts is similar to loss of habitat due
to development; loss of low-lying forest
habitat could result in decreased habitat
availability for the Virgin Islands boas
and their prey.
Persecution by Residents
Intentional killing of the more
common and larger sized Puerto Rican
boa (Chilabothrus inornatus) due to fear
or superstitious beliefs has been well
documented in the literature (Bird-Pico´
1994, p. 35; Puente-Rolo´n and Bird-Pico´
2004, p. 343; Joglar 2005, p. 146). Thus,
Virgin Islands boas in proximity to
developed areas where people fear
snakes are susceptible to intentional
killings. Public encounters with Virgin
Islands boas in the more populated Rı´o
Grande and Culebra locations are
considered questionable because of the
rarity of boas in those populations, and
there are only a couple of anecdotal
records of intentional killings between
those areas (Service 2009, pp. 15–16). In
the highly developed east side of St.
Thomas, about 10 percent of the Virgin
Islands boa records in St. Thomas are
from dead boas killed by humans on
private property (Platenberg 2006,
unpub. data). We have no further
information to assess the magnitude of
this threat, but it is likely that
intentional killings of Virgin Islands
boas still occur, are not being
documented, and would be particularly
detrimental to rare populations such as
in Rı´o Grande. The Service is not aware
of a law enforcement case related to the
boa in Puerto Rico or the USVI.
Populations that occur within protected
areas are not expected to be exposed to
this threat.
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Conservation Measures That Affect the
Species
Positive influences on Virgin Islands
boa viability have been habitat
protection, predator control, and captive
breeding and reintroduction. Two
populations of Virgin Islands boa were
reintroduced to protected cays after
predators had been removed, one on
Cayo Ratones (Puerto Rico) in 1993, and
another on USVI Cay in 2002. Founders
for these reintroductions came largely
from a cooperative captive-breeding
program initiated in 1985 between the
Service, DNER, VIDPNR, and the Toledo
Zoological Garden. Cayo Diablo
provided the founding individuals for
the captive population that was
reintroduced to Cayo Ratones (6
kilometers (3.5 miles) away from Cayo
Diablo), and St. Thomas provided the
founding individuals for the captive
population that was reintroduced to the
USVI Cay (4 kilometers (2.5 miles) away
from St. Thomas).
The Cayo Ratones population
originated from 41 captive-born boas
(offspring of Cayo Diablo boas) released
between 1993 and 1995. Post-release
survival was high: 82.6 percent of
individuals and 89 percent of neonates
survived at least 1 year (Tolson 1996a,
unpaginated). By 2004, the population
had grown to an estimated 500 boas
(Tolson et al. 2008, p. 68).
Unfortunately, since 2004, Cayo Ratones
has been recolonized by rats, and no
boas were found during surveys in 2018
(Island Conservation 2018, pp. 5, 20).
However, because Virgin Islands boas
are difficult to find, and this survey was
not exhaustive, we believe it is
premature to conclude the population
has been extirpated. Intensive follow-up
surveys are needed to confirm whether
a population still persists or is
extirpated, but it is clear that the
population has declined.
The USVI Cay reintroduction was
initiated with the release of 42 Virgin
Islands boas in 2002 and 2003, 11 from
captivity and 31 from St. Thomas.
Follow-up surveys in 2003–2004
provided an estimate of 168 boas (202
boas/ha), which researchers suspected
was near carrying capacity for the island
(Tolson 2005, p. 9). More recent surveys
in 2018 detected 20 boas over 2 nights,
resulting in an estimate of 26–33 boas
across the island (Island Conservation
2018, pp. 20–30). Differences in survey
and analysis methodologies complicate
direct comparisons of population size
between these time points. Recent
surveys also indicate that there are no
rats on the island.
Factors for consideration for future
reintroduction sites include the
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presence and amount of suitable habitat
(e.g., appropriate forest structure,
adequate prey base, available refugia),
protection status or threat of
development, the presence/absence/
eradication of exotic predators, and
geomorphology that provides protection
from SLR and hurricane storm surges
that are likely to affect the persistence
of low-lying habitat. Potential sites for
new introductions have been suggested
(Reynolds et al. 2015, p. 499) and need
to be further assessed, although one new
effort is in the early stages of
implementation. Some areas may
require that predators be removed before
boas are moved and future monitoring is
ensured to prevent recolonization. In
addition to reintroductions to new sites,
augmentation of existing populations
may prove beneficial or necessary for
the persistence of existing populations,
particularly on developed islands and
cays where predators have become
reestablished.
In conclusion, the Virgin Islands boa
still faces the threat of development on
St. Thomas, Rı´o Grande, and Culebra
Island, and regulatory mechanisms
addressing this threat are difficult to
enforce or do not cover all development
actions affecting the species. Human
development results in habitat loss from
deforestation and fragmentation,
mortality from vehicular strikes, and
increased predation by cats and rats. In
addition, impacts from changes in
climate could affect habitat. Drought
could negatively influence Virgin
Islands boa populations through loss of
prey. SLR and storm surges are expected
to inundate low-lying islands, such as
Cayo Diablo, Cayo Ratones, and the
USVI Cay, which currently support
Virgin Islands boa populations. Finally,
persecution of boas by citizens, due to
fear or superstition, can affect
individual boas, although there has
never been a systematic study of the
impact of these events on the overall
population.
When considering conservation
actions and how they influence the
viability of Virgin Islands boa, about
half of known localities where Virgin
Islands boas occur are on small offshore
islets managed for conservation. In
addition, predator removal has been
successful at smaller cays, such as USVI
Cay, although the reestablishment of
rats on Cayo Ratones illustrates the need
for continued monitoring and removal
efforts. Lastly, successful
reintroductions of Virgin Islands boas
occurred on these islands after the
eradication of predators; however,
additional predator removal and
augmentation of reintroduced boa
populations may be needed on cays
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where predators have become
reestablished.
Summary of Current Condition
For the Virgin Islands boa to maintain
viability, its populations, or some
portion thereof, must be resilient. For
the SSA, our classification of resiliency
relied heavily on habitat characteristics
in the absence of highly certain
population size or trend estimates. The
habitat characteristics we assessed were:
Degree of habitat protection (or,
conversely, development risk), presence
of introduced predators, and
vulnerability to storm surges (Service
2018, p. 31).
Representation can be measured by
the breadth of genetic or environmental
diversity within and among populations
and gauges the probability that a species
is capable of adapting to environmental
changes. A range-wide genetic analysis
of the Virgin Islands boa showed there
was little genetic variation; however, the
same study found that each sampled
locality had unique mtDNA haplotypes,
indicating a lack of gene flow between
islands (Rodrı´guez-Robles et al. 2015,
entire). Therefore, in the SSA we used
genetics to delineate representative
units.
The species also needs to exhibit
some degree of redundancy in order to
maintain viability. Catastrophic events
that could affect both single and
multiple populations of the Virgin
Islands boa include drought, hurricanes,
and colonization or recolonization of
exotic predators. This species occurs in
geographically isolated groups and does
not disperse from island to island to
interact and interbreed; therefore, for
purposes of analyzing redundancy, all
boas within each island were
considered to be individual
populations.
Resiliency
Because resiliency is a populationlevel attribute, the key to assessing it is
the ability to delineate populations. As
discussed above, we considered all boas
within each island to be single
populations. On small offshore cays,
what we define as a population might
consist of a single interbreeding deme
(or subdivision) of Virgin Islands boas.
On larger islands, what we define as a
population functions more as a
metapopulation, with multiple
interbreeding groups in isolated habitat
patches that may interact weakly via
dispersal and recolonization of
extirpated patches. Alternately, multiple
occupied patches on large islands may
be completely isolated from one another
(Service 2018, p. 20).
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Six island populations were
considered: Cayo Diablo, Cayo Ratones,
Culebra Island, Rı´o Grande (Puerto
Rico), St. Thomas, and USVI Cay
(USVI). We acknowledge the
uncertainty about the persistence of
Virgin Islands boas on Cayo Ratones due
to the recolonization of the island by
rats; however, because of reasons
described previously, we included this
island in our analysis. Further, one or
more populations exist in the BVI, but
data are severely limited, and for the
SSA, we lacked sufficient data from
these islands to incorporate them into
our viability analysis. In addition, other
populations may occur on islands in
Puerto Rico and USVI, but Virgin
Islands boa habitat and activity patterns
make them difficult to find, and we
could not confirm any to be extant at the
time we completed our analysis.
Resiliency scores for each population
were generated by combining scores for
three habitat metrics (Protection/
Development Risk, Exotic Mammals,
and Storm Surge Risk) and one
population metric (Population Size and/
or Trend, dependent on availability).
Each metric was weighted equally, with
the overall effect that habitat (three
metrics) was weighted three times
higher than population size/trend (one
metric). For each metric, populations
were assigned a score of ¥1, 0, or 1, as
described below in table 1.
The scores were based on the best
available information for each
population, gathered from the literature
61707
and species experts. Monitoring data are
scarce. The Virgin Islands boa recovery
plan (Service 1986, pp. 16–19) called for
periodic monitoring to estimate
population sizes and trends, but surveys
since then have been few and far
between. Survey methodology and
reporting have varied from population
to population, with survey results given
as estimated abundances, estimated
densities, or encounter rates per personhour of searching. The above-described
factors in combination contribute to
high levels of uncertainty in current and
past population sizes, and how they
have changed over time. Accordingly,
resiliency classifications relied more
heavily on habitat conditions than
population size and trend estimates.
TABLE 1—DESCRIPTION OF HABITAT AND POPULATION FACTOR SCORES TO DETERMINE VIRGIN ISLANDS BOA
POPULATION RESILIENCY
Habitat metrics
Score
Habitat protection/
development risk
Population metric
Exotic mammals
Storm surge risk
Population
size/trend *
Topography and elevation
leaves population vulnerable to storm surges.
NA ..........................................
Relatively low population size
and/or declining trend.
–1 ...................
Habitat not protected, at risk
of being developed.
Exotic mammals present .......
0 .....................
Some habitat protected, some
at risk of being developed.
NA ..........................................
1 .....................
Habitat protected in identified
protected area.
Exotic mammals absent .........
Protected by topography and
elevation.
Relatively moderate population size and stable trend,
OR High degree of uncertainty in population size/
trends.
Relatively high population
size and/or growth.
* Population size/trend scores are relative and were based on the best available information for each population, gathered from the literature
and species experts.
The scores for each population across
all metrics were summed, and final
population resiliency categories were
assigned as follows:
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Low Resiliency: –4 to –2
Moderately Low Resiliency: –1
Moderate Resiliency: 0
Moderately High Resiliency: 1
High Resiliency: 2 to 4
Applying these resiliency categories
to the six populations of Virgin Islands
boa, we determined that one population
has moderately high resiliency (Cayo
Diablo), one has moderate resiliency
(USVI Cay), one has moderately low
resiliency (Culebra), and three have low
resiliency (Cayo Ratones, Rı´o Grande,
and St. Thomas).
The population classified as having
moderately high resiliency (Cayo
Diablo) occurs on a small offshore
island that is free of exotic rats and cats
and is protected for conservation. In
addition, Cayo Diablo was surveyed in
2018 with 10 boas being found (Island
Conservation 2018). Extrapolating the
density within the transect area (2.9
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boas/ha) to the entire island, the model
provides an estimate of 20 boas on the
island (95% confidence interval 13–39),
which is much lower than earlier
unpublished survey results, however
comparisons cannot be made between
the surveys because of different survey
and analytical methodologies (Service
2018, p.23). Primarily because of the
protected and exotic-mammal-free state
of the habitat, this population is
considered to have moderately high
resiliency to demographic and
environmental stochastic events and
disturbances (e.g., fluctuations in
demographic rates, variation in climatic
conditions, illegal human activities).
The USVI Cay population, also on a
protected offshore island with no exotic
mammals, was determined to have
moderate resiliency. Recent surveys
have revealed a potential decline in
abundance and the loss of two prey
species (Smith 2018a, pp. 7–8), possibly
as a result of density dependence as the
population approached carrying
capacity after reintroduction. Over two
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separate survey efforts in 2018,
researchers found a total of 64 boas
(Smith 2018ab, entire).
Three of the populations (Rı´o Grande,
Culebra, and St. Thomas) with low or
moderately low resiliency occur on
larger and higher elevation islands,
which provide more protection from
storm surges, but have more human-boa
interactions, habitat loss and
fragmentation from development, and
exotic cats and rats. Recent surveys in
2018 on Rı´o Grande found three boas
(three survey nights) (Island
Conservation 2018, p. 20). For Culebra,
surveys in 2018 found no boas (Island
Conservation 2018, p. 20); however, two
individuals were documented in
February 2019 within the Culebra
National Wildlife Refuge (Puente-Rolo´n
and Vega-Castillo 2019, p. 18). On
October 2019, another individual was
confirmed in an area outside of the
Refuge (Roma´n 2019, pers. comm.). For
St. Thomas, there have been no recent
systematic surveys for the species as
much of eastern St. Thomas is
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inaccessible due to private ownership or
impenetrable habitat; however,
opportunistic observations have
averaged about 10 observations of Virgin
Islands boa per year since 2000. The
remaining low-resiliency population
(Cayo Ratones) is classified as such as
a result of the recolonization of rats on
the island and resulting declining
trend—or possible extirpation—of boas,
as no boas were detected during recent
survey efforts (Island Conservation
2018).
Representation
A range-wide genetic analysis of
Virgin Islands boa showed that there
was little genetic variation within the
species (Rodrı´guez-Robles et al. 2015, p.
150), supporting the idea that there is
only one representative unit of Virgin
Islands boa. However, each sampled
island, and each sampled locality
within the same island, had unique
mtDNA haplotypes, indicating a lack of
gene flow between islands/populations
(Rodrı´guez-Robles et al. 2015, p. 150).
These results suggest that each
population has a different genetic
signature, perhaps as a result of genetic
adaptations to their local environment,
or genetic drift with increasing isolation
of small populations. The
reintroduction program took this view,
and managed captive populations
sourced from Cayo Diablo and St.
Thomas separately (Tolson 1996b, p.
412). To minimize the chances of
introducing individuals poorly suited to
their new environment, the captive
population sourced from Cayo Diablo
founded the reintroduced population on
nearby Cayo Ratones, and the captive St.
Thomas population founded the
reintroduced population on the nearby
USVI Cay (Tolson 1996b, p. 412).
In addition to genetic differences, the
six populations also have noticeable
phenotypic differences. These are not
just limited to coloration differences
between USVI and Puerto Rican
populations (Tolson 1996b, p. 412);
Cayo Diablo reportedly has lighter
coloration than the Rı´o Grande and
Culebra populations (Tolson 2018, pers.
comm.). The Rı´o Grande population also
occurs in a different habitat type
(subtropical moist forest) than the others
(subtropical dry or littoral forest; Tolson
1996b, p. 410).
In light of this information, we
considered each of the four natural
populations in Puerto Rico and USVI as
a representative unit (table 2). The Cayo
Diablo population is considered to have
moderately high resiliency. As this was
the source for the low-resiliency Cayo
Ratones population, there are two
populations representing the Cayo
Diablo genetic signature. Similarly, the
USVI Cay population was sourced from
St. Thomas, so there are two
populations with St. Thomas
representation, with neither considered
to have high resiliency. The other two
natural populations, Culebra and Rı´o
Grande, both characterized as having
moderately low or low resiliency, have
not been used for captive breeding and
reintroduction, so have no additional
populations on other islands with the
same genetic characteristics. Overall,
three of four representative units have at
least one moderate resilient population.
While currently we could consider
the USVI Cay and Cayo Ratones
reintroduced populations (currently
with moderate and low resiliency,
respectively) to be redundant
populations sharing the same genetic
signature and adaptive potential as their
source populations, all of the islands
occupied by Virgin Islands boa are
isolated from each other. Without
human-mediated movement of boas
between islands, the reintroduced
populations are expected to diverge
genetically from their source
populations over time, and may at some
point in the future (decades to centuries;
Reynolds et al. 2015, entire) be different
enough to be considered its own unique
representative unit.
TABLE 2—REPRESENTATION: NUMBER OF VIRGIN ISLANDS BOA POPULATIONS OF EACH RESILIENCY CLASS IN EACH REPRESENTATIVE UNIT, CORRESPONDING TO NATURAL (NOT INTRODUCED) POPULATIONS, WHICH THEMSELVES CORRESPOND TO UNIQUE GENETIC SIGNATURES
Moderately
high resiliency
populations
Natural population
(genetic signature)
Cayo Diablo .....................................................................................................
Culebra ............................................................................................................
Rı´o Grande ......................................................................................................
St. Thomas ......................................................................................................
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Redundancy
Redundancy describes the ability of a
species to withstand catastrophic
events. Measured by the number of
populations, their resiliency (ability of a
species to withstand environmental and
demographic stochasticity (e.g., wet or
dry years)) and their distribution (and
connectivity), redundancy gauges the
probability that the species has a margin
of safety to withstand or return from
catastrophic events (such as a rare
destructive natural event or episode
involving many populations).
The exact historical distribution of the
Virgin Islands boa is unknown, but their
present disjointed distribution suggests
that they were once more widely
distributed across small islands within
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1
0
0
0
their range, which have been subject to
local extirpations from habitat
degradation, invasive species, and
historical climate and sea level changes.
However, for current redundancy, we
identified the six populations in Puerto
Rico and USVI (and one or more
populations in the BVI of unknown
status). As discussed above, three of
these populations are considered to
have resiliency; therefore, the species is
moderately buffered against the effects
of catastrophic events.
Summary
Of the six assessed populations, the
Cayo Diablo population is the only one
that currently has moderately high
resiliency, the USVI Cay population has
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Moderate
resiliency
populations
Moderately
low resiliency
populations
0
0
0
1
0
1
0
0
Low resiliency
populations
1
0
1
1
moderate resiliency, and the Culebra
population has moderately low
resiliency. The other three assessed
populations currently have low
resiliency. Redundancy for the species
includes populations on six islands in
Puerto Rico and USVI, and possibly
more in the BVI, although not part of
this assessment. Representation consists
of four representative units, two of
which have two populations
representing its genetic signature, and
three of the four units have populations
with some level of resiliency.
The Virgin Islands boa has
demonstrated some ability to adapt to
changing environmental conditions over
time from both anthropogenic threats
(e.g., habitat disturbance due to
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development) and natural disturbances
(e.g., predation and hurricanes).
Compared to historical distribution at
the time of listing that included three
locations (Puerto Rico, St. Thomas, and
Tortola), the species currently has six
populations (potentially more if the
species persists in the BVI and others
are eventually confirmed). Three of the
six current populations exhibit varying
levels of resiliency from moderately
high to moderately low, whereas three
exhibit low resiliency. Since the species
was listed as an endangered species in
1970, it has demonstrated some degree
of resiliency despite threats.
Future Conditions
To assess the future resiliency,
redundancy, and representation for the
Virgin Islands boa, we considered
impacts of human development, habitat
protection and restoration,
reintroductions, public outreach and
education, and SLR. We predicted
resiliency at two future time points, 30
years and ∼80 years in the future (2048
and 2100). Predictions made at the 80year time point are based only on SLR
and hurricane storm surges as
predictions about the other factors are
too uncertain to allow for a meaningful
analysis. As discussed in Determination
of Status below, all of the impacts were
considered at the 30-year time step.
With input from species’ experts, we
chose the 30-year time step in order to
encompass multiple generations of
Virgin Islands boa (which can live past
20 years and reproduce at 2–3 years of
age; Tolson 1989, p. 166; Tolson and
Pin˜ero 1985, unpaginated). In addition,
we considered the time required to plan
and execute a reintroduction (about 10
years; Tolson 2018, pers. comm.) and
how a 30-year time step would allow us
to see results of reintroduction efforts.
Lastly, we considered the time required
for habitat restoration to be realized (10
years or less; Platenberg 2018, pers.
comm). The 30-year time step coincides
with the foreseeable future for this
analysis (i.e., the period of time in
which we can make reliable
predictions). For information on
predictions made at the 80-year time
step, see the SSA report (Service 2018,
pp. 38–46).
We did not explicitly consider the
role that genetics may play in the future.
Although the absence of natural
migration of boas between islands
isolates these populations and makes
them vulnerable to inbreeding and
genetic drift, no genetic abnormalities or
evidence of inbreeding depression have
been observed in the boa (Tolson 1996b,
p. 412). We also did not explicitly
consider the impacts of climate change
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(other than SLR and hurricane storm
surges) on the boas and their habitat.
Species that are dependent on
specialized habitat types and limited in
distribution and migration ability, such
as the Virgin Islands boa, are susceptible
to the impacts of climate change (Byers
and Norris 2011, p. 22), but the
direction, magnitude, and timeframe of
these impacts on the species are
uncertain.
Below we present three plausible
future scenarios for the Virgin Islands
boa over the next 30 years (to 2048):
Status Quo, Conservation, and
Pessimistic. Impacts of climate change
and SLR are treated the same across all
three scenarios, as the trajectory of
climate change will proceed regardless
of different levels of local conservation
for Virgin Islands boa. For all three
scenarios, SLR is considered to occur at
a rate of 0.30 meters (1 foot) by 2048,
and 0.61–0.91 meters (2–3 feet) by 2100
(Church et al. 2013; Service 2018, pp.
38–41). Multiple major hurricanes are
expected to strike within the Virgin
Islands boa’s range.
Under a status quo scenario:
Development continues at the current
pace, and development and exotic
mammals continue to negatively impact
Virgin Islands boa populations. Boa
population sizes in these developed
areas decline, as they are suspected to
currently be in decline by species
experts (but hard data are lacking to
confirm trends). No new habitat is
protected. Under this scenario, one new
reintroduction that has already been
initiated with the 2018 capture of
snakes to reinvigorate captive breeding
takes place.
Under a conservation scenario: While
development continues on humanoccupied islands, under this scenario
new Virgin Islands boa habitat is
protected from development on the
Puerto Rico main island, and additional
habitat is protected on Culebra and St.
Thomas (where some habitat is already
protected), to preserve and restore
habitat and habitat connectivity.
Because of the size of the islands and
human populations there, exotic cats
and rats remain problematic, but this
risk would be reduced by conservation
efforts including predator control and
effective community outreach and
education about the effect of freeroaming cats on native wildlife.
Regulations and enforcement improve
on protected lands. Rats are eradicated
(and eradication efforts are monitored)
from Cayo Ratones and, if necessary,
more boas are translocated there.
Reintroductions occur at a rate of one
site per decade, including the one
reintroduction already planned, and
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61709
struggling populations on developed
islands are augmented.
Under a pessimistic scenario: Under
the Pessimistic scenario, no
reintroductions occur, presumably due
to reduced funds or changes in
governmental or conservation priorities.
No additional habitat is protected, and
development continues to impact
populations on human-inhabited
islands. Exotic mammals remain a threat
where already present. Rats colonize
Cayo Diablo and recolonize the USVI
Cay.
Given current resources, priorities,
and conservation momentum, the Status
Quo scenario is the most likely scenario
for the future. The Status Quo scenario
includes the implementation of a new
reintroduction, which is planned but
contingent on continued funding (not
yet secured) and a long-term
commitment to manage and propagate a
captive population, select a suitable site
(which may involve rat eradication),
reintroduce boas, and conduct postrelease monitoring. The likelihoods of
the Conservation and Pessimistic
scenarios are contingent upon the
decisions, resources, and priorities of
management and conservation
organizations, which are difficult to
predict. The Pessimistic scenario is
likely if funds and effort are not directed
to captive breeding and reintroduction,
community outreach and education,
habitat protection and restoration, and
ongoing monitoring of Virgin Islands
boas, their habitat, and exotic species.
The Conservation scenario is likely if
abundant funds and effort are directed
towards these initiatives.
Resiliency
Under all three future scenarios, the
three populations on developed islands
are predicted to remain at low resiliency
or become extirpated by 2048 (table 3).
Even with conservation efforts to
prevent extirpation, none of the
populations are expected to improve
their resiliency because of the
magnitude of the threats facing them.
Cayo Diablo, the population with the
highest resiliency, is expected to
continue to have high resiliency unless
the island is colonized by rats, which
could drive the population to
extirpation. Cayo Ratones, which
presently has a robust rat population,
will remain at low resiliency and
potential extirpation unless rats are
eradicated; supplemental translocations
may also be necessary, but more surveys
are necessary to determine the needs of
the population. Given that the threats
facing populations on developed islands
will be very difficult to surmount, the
most effective way to increase the
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overall resiliency of populations rangewide is to reintroduce new populations
in quality protected habitat, prevent
future colonization by exotic predators,
and have continual predator eradication
monitoring.
TABLE 3—SUMMARY TABLE OF FUTURE RESILIENCY FOR VIRGIN ISLANDS BOA POPULATIONS IN 2048 UNDER THREE
SCENARIOS
Population
Current resiliency
Future—status quo
(2048)
Future—conservation
(2048)
Cayo Diablo .......................
Cayo Ratones ....................
Culebra ..............................
Rı´o Grande ........................
St. Thomas ........................
USVI Cay ...........................
New (introduced) populations (pops).
Summary (# pops) .............
Moderately High ................
Low ....................................
Moderately Low .................
Low ....................................
Low ....................................
Moderate ...........................
None ..................................
Moderately High ................
Low/Extirpated ..................
Low/Extirpated ..................
Low/Extirpated ..................
Low/Extirpated ..................
Moderate ...........................
1 High ................................
High ...................................
High ...................................
Moderately Low .................
Low ....................................
Low ....................................
High ...................................
3 High ................................
Low/Extirpated.
Low/Extirpated.
Low/Extirpated.
Low/Extirpated.
Low/Extirpated.
Low/Extirpated.
None.
6 pops ...............................
Low: 3 ...............................
Mod Low: 1 .......................
Moderate: 1 .......................
Mod High: 1 ......................
3–7 pops ...........................
Low/Extirpated: 4 ..............
Moderate: 1 .......................
Mod High:1 ........................
High: 1 ...............................
9 pops ...............................
Low: 2 ...............................
Mod Low:1 ........................
High: 6 ...............................
0–6 pops.
Low/Extirpated: 6.
High: 0.
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Redundancy
The total number of populations
under the Status Quo scenario is three
to seven depending on whether four
populations become extirpated or
remain at a low resiliency. Under the
Pessimistic scenario, all populations are
predicted to be extirpated or remain at
low resiliency. The Conservation
scenario improves redundancy by
introducing three new populations that
are expected to have high resiliency,
improving the resiliency of the Cayo
Ratones population by eradicating rats
and providing translocations if needed,
and preventing low-resiliency
populations from becoming extirpated,
for a total of nine populations. As time
goes on after the horizon of our 30-year
scenarios, SLR becomes more important
to consider, as current populations with
the highest resiliency potential are the
same populations that will be most at
risk from SLR.
Representation
In the Current Condition section
above, we identified each natural (not
introduced) Virgin Islands boa
population as a representative unit.
Under this concept, a reintroduced
population is of the same representative
unit as the source population used for
the reintroduction, and future
representation for the species depends
highly on how reintroductions are
carried out (table 11 in Service 2018, p.
59).
The Status Quo scenario includes one
reintroduction sourced from the USVI
Cay population, which was originally
sourced from the St. Thomas
population. Therefore, the new
reintroduced population would be
considered part of the St. Thomas
representative unit. The Conservation
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scenario includes two additional
reintroductions, which could be sourced
from any population. Sourcing new
reintroductions from Culebra or Rı´o
Grande would improve redundancy
within representative units, but other
factors such as geographic proximity to
the reintroduction site and availability
of source boas also factor into the
decision of where to source
reintroductions. The Pessimistic
scenario does not include any new
reintroduced populations.
Summary
Conservation of existing populations
of Virgin Islands boas and their habitat
on developed islands, via population
augmentation and habitat restoration (in
occupied areas and to establish
migration corridors), is important to
contribute to resiliency and redundancy
within representative areas for the
species. The future condition of the
Virgin Islands boa was assessed under
three scenarios 30 years into the future.
Under the Status Quo scenario,
development continues to impact the
populations on developed islands, no
new habitat is protected, and one new
reintroduction takes place. Two
moderately high or high-resiliency
populations are predicted to remain
after 30 years (Cayo Diablo and a new
reintroduced population), while USVI
Cay remains in moderate resiliency, and
the remaining four populations are
predicted to have low resiliency or
potentially be extirpated.
Under the Conservation scenario,
some habitat on the three developed
islands is protected for conservation/
restoration, reintroductions occur at a
rate of one per decade, and presence of
exotic mammals are monitored and
controlled (though likely not eradicated)
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Future—pessimistic
(2048)
via continuous eradication efforts and
public outreach. Six high-resiliency
populations are predicted to exist after
30 years. Under this scenario, three
populations are expected to have
moderately low or low resiliency, but
are protected from complete extirpation
by active conservation measures. Under
the Pessimistic scenario, development
continues to impact populations on
developed islands, no reintroductions
occur, and rats colonize/recolonize the
islands where they are not currently
present. No highly resilient populations
are predicted to remain after 30 years,
and all six current populations are at
risk of extirpation.
Redundancy increases under the
Status Quo and Conservation scenarios;
however, under the Pessimistic
scenario, no high-resiliency populations
remain. Representation remains the
same four units under the Status Quo
scenario. Under the Conservation
scenario, redundancy may improve
within representative units with the
addition of two more reintroduced
populations, depending on where those
populations are sourced. Based on our
analysis, we consider the Status Quo
scenario to be the most likely scenario,
and therefore expect the Virgin Islands
boa will have three resilient populations
at our 30-year timeframe, with
continued redundancy and
representation.
We also assessed the risk from SLR
and hurricanes at 30 years into the
future. In 30 years, SLR alone is
unlikely to significantly impact Virgin
Islands boa populations, with
approximately 4–5 percent of land
predicted to be inundated (Service 2018,
p. 43). Habitat on low-lying cays (Cayo
Diablo, Cayo Ratones, and USVI Cay)
has proven to be resilient to hurricanes
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in the past, and likely will remain so
with 0.30 meters (1 foot) of SLR
expected over the next 30 years,
although the exact impacts of any
particular future storm are impossible to
predict. Overall, USVI Cay is most at
risk from SLR and storm impacts, while
there is a moderate risk of SLR impacts
to Virgin Islands boas and habitat on
Cayo Diablo and Cayo Ratones, and low
risk at Culebra, Rı´o Grande, and St.
Thomas.
We note that, by using the SSA
framework to guide our analysis of the
scientific information documented in
the SSA report, we have not only
analyzed individual effects on the
species, but we have also analyzed their
potential cumulative effects. We
incorporate the cumulative effects into
our SSA analysis when we characterize
the current and future condition of the
species. Our assessment of the current
and future conditions encompasses and
incorporates the threats individually
and cumulatively. Our current and
future condition assessment is iterative
because it accumulates and evaluates
the effects of all the 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.
Recovery and Recovery Plan
Implementation
Section 4(f) of the Act directs us to
develop and implement recovery plans
for the conservation and survival of
endangered and threatened species
unless we determine that such a plan
will not promote the conservation of the
species. Recovery plans are not
regulatory documents and are instead
intended to establish goals for long-term
conservation of a listed species; define
criteria that are designed to indicate
when the threats facing a species have
been removed or reduced to such an
extent that the species may no longer
need the protections of the Act; and
provide guidance to our Federal, State,
and other governmental and
nongovernmental partners on methods
to minimize threats to listed species.
There are many paths to
accomplishing recovery of a species,
and recovery may be achieved without
all of the criteria in a recovery plan
being fully met. For example, one or
more criteria may be exceeded while
other criteria may not yet be
accomplished. In that instance, we may
determine that the threats are
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minimized sufficiently and the species
is robust enough to delist. In other
cases, recovery opportunities may be
discovered that were not known when
the recovery plan was finalized. These
opportunities may be used instead of
methods identified in the recovery plan.
Likewise, information on the species
may be learned that was not known at
the time the recovery plan was
finalized. The new information may
change the extent to which existing
criteria are appropriate for recognizing
recovery of the species. Recovery of a
species is a dynamic process requiring
adaptive management that may, or may
not, follow all of the guidance provided
in a recovery plan.
The Virgin Islands Tree Boa Recovery
Plan, issued by the Service on March 27,
1986, did not contain measurable
criteria. An amendment to the recovery
plan was issued in September 2019 to
include quantitative delisting criteria.
The amended recovery plan suggests
that recovery be defined in the
following terms:
• Delisting Criterion 1. Existing two
(2) Virgin Islands boa populations with
the highest resiliency (Cayo Diablo and
USVI Cay) exhibit a stable or increasing
trend, evidenced by natural recruitment
and multiple age classes. This criterion
has been partially met. Ensuring the
conservation of resilient populations is
important for the recovery of the Virgin
Islands boa as it will help those
populations to further withstand
catastrophic and stochastic events. The
populations of the Virgin Islands boa at
Cayo Diablo and USVI Cay are
considered potentially declining
(Tolson 2004, p. 11; Tolson et al. 2008,
p. 68), and currently have moderately
high and moderate resiliency,
respectively (Service 2018, pp. 23, 28).
Both Cayo Diablo and USVI cay are free
of exotic predators/competitors and are
protected as part of natural reserves.
Habitat conditions are recovering
following hurricanes, and Virgin Islands
boas continue to persist, with upwards
of 20 boas estimated on Cayo Diablo,
and boas appear to be at carrying
capacity on USVI Cay (Service 2018, pp.
23, 28). In addition, these resilient
populations may serve as sources to
establish the new populations outlined
in Criterion 2, if maintained at their
current level. Virgin Islands boas have
already been collected from the USVI
Cay population to establish a captivebreeding program in order to implement
Criterion 2.
Five islands (Culebra, Rı´o Grande
(Puerto Rico), St. Thomas, Cayo
Ratones, and Tortola) currently have
Virgin Islands boas present, although
population numbers and age class
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structures are unknown. Cayo Ratones
had a thriving population, with 41
introduced boas in 1993–1995 having
high survival and wild reproduction
and were able to increase numbers to
nearly 500 boas by 2005 (Tolson et al.
2008, p. 68; Service 2018, p. 24).
However, recent surveys in 2018 did not
detect any boas, but did uncover a
robust rat population (Island
Conservation 2018, entire; Service 2018,
p. 24). Because Virgin Islands boas are
hard to find and habitat conditions
remain in good condition post
hurricanes, there is not enough evidence
to indicate boa extirpation, although the
reestablishment of rats is likely causing
decline in this population. For Culebra,
surveys in 2018 found no boas (Island
Conservation 2018, p. 20); however, two
individuals were documented in
February 2019 within the Culebra
National Wildlife Refuge (Puente-Rolo´n
and Vega-Castillo 2019, p. 18). On
October 2019, another individual was
confirmed in an area outside of the
Refuge (Roma´n 2019, pers. comm.). The
Puerto Rican Rı´o Grande population has
consistent but very low encounter rates
for Virgin Islands boas, with three
observed during recent 2018 surveys.
These two populations were determined
to have low (Rı´o Grande) and
moderately low (Culebra) resiliency.
Similarly, the species has been sighted
on St. Thomas (Platenberg and Harvey
2010, entire), and earlier estimates
assessed the population to be about 400
individuals (Tolson 1991, p. 11).
Despite lack of recent surveys on St.
Thomas (primarily due to inaccessibility
of habitat), opportunistic reports
indicate approximately 10 Virgin
Islands boa observations per year since
2000 (Service 2018, p. 27). The SSA
classifies this population as having low
resiliency. Virgin Islands boas are
known to occur on Tortola (and likely
several other British Virgin islands);
however, no data are available about the
size or status of those populations
(Service 2018, p. 29).
• Delisting Criterion 2. Establish three
(3) additional populations that show a
stable or increasing trend, evidenced by
natural recruitment and multiple age
classes. This criterion has not been met.
Increasing the number of resilient
populations will improve the species’
viability. In order to expand the species’
distribution, these new populations will
be established on protected suitable
habitat where threats from invasive
mammals are not present and SLR will
have minimal impact on the habitat. In
addition, increasing the number of
populations and broadening the species’
distribution will enhance their ability to
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withstand catastrophic and stochastic
events. For this species, it is believed
that three additional populations
exhibiting these traits is necessary to
ensure sufficient redundancy such that
the species will no longer require
protection under the Act.
• Delisting Criterion 3. Threats are
reduced or eliminated to the degree that
the species is viable for the foreseeable
future. This criterion has been partially
met. The primary threats to Virgin
Islands boa are development, predation/
competition from exotic mammals,
climate change, and persecution from
the public. Virgin Islands boa
populations have coexisted with urban
development on Culebra, Rı´o Grande,
St. Thomas, and several British Virgin
islands, although impacts from the
development appear to cause a decline
in these populations. Consequences of
human development on the boa and its
habitat include habitat loss and
fragmentation due to deforestation,
mortality from vehicular strikes, and an
increase in predators/competitors, such
as cats and rats. Three islands (Cayo
Diablo, Cayo Ratones, and USVI Cay)
are protected from development
impacts. The threat of predation/
competition by exotic mammals can be
reduced/eliminated, but requires
continual monitoring and eradication
efforts. In 1985, a successful rat control
program was started, and Cayo Ratones
and USVI Cay were identified as
potentially suitable for the
reintroduction of the species. At one
time, rats had been eliminated on Cayo
Ratones, but they have since returned
and are in robust numbers. Rats on
USVI Cay have been eliminated, and
Virgin Islands boas are established
there. In areas where urban
development is prevalent, it is unlikely
that feral cats and rats will be fully
eradicated. Storm surge and SLR are the
effects of climate change that are
projected to impact Virgin Islands boa
populations; however, the species has
thus far proven to be resilient to severe
storms (and associated storm surge) and
SLR is not expected to significantly
impact the species in the foreseeable
future (see Future Conditions, above).
Finally, intentional killing of Virgin
Islands boas, whether due to fear of
snakes or confusion with other snakes,
has been identified as a threat; however,
the extent of the effect of persecution on
Virgin Islands boa populations is
unknown.
Summary
The amended Virgin Islands boa
recovery plan (Service 2019) contains
three recovery criteria for delisting the
species: Two Virgin Islands boa
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populations exhibit a stable or
increasing trend, evidenced by natural
recruitment and multiple age classes;
three additional populations show a
stable or increasing trend, evidenced by
natural recruitment and multiple age
classes; and threats are reduced or
eliminated to the degree that the species
is viable for the foreseeable future.
Based on the information gathered and
analyzed, two of these criteria have been
partially met.
Determination of Virgin Islands Boa
Status
Section 4 of the Act (16 U.S.C. 1533),
and its implementing regulations at 50
CFR part 424, set forth the procedures
for determining whether a species meets
the definition of endangered species or
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
‘‘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
‘‘endangered species’’ or ‘‘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.
Status Throughout All of Its Range
After evaluating threats to the species
and assessing the cumulative effects of
the threats under the section 4(a)(1)
factors, we find that, while the present
or threatened destruction, modification,
or curtailment of its habitat (Factor A)
remains a threat for at least three of the
populations, three of the six populations
fully occur in protected areas, and we
expect the species’ population
resiliency to ameliorate the threat in the
future. The Virgin Islands boa’s habitat
is found on both private and publicly
owned lands. Past, current and
expanding urban development will
continue to impact the Virgin Islands
boa on the main islands (i.e., St.
Thomas, Rı´o Grande (Puerto Rico), and
Culebra), which are under development
pressure related to urban expansion and
tourism; however, not all areas of the
species’ range occur near population
centers. Half of the currently known
populations are found on islands and
small islets that are managed for
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conservation by the territorial
governments of Puerto Rico and USVI,
and the Culebra Island population
occurs both within private and
protected areas (i.e., Culebra National
Wildlife Refuge).
Predation by exotic mammals, namely
cats and rats, remains a threat to the
Virgin Islands boa (Factor C). While
there is no evidence of rats preying
directly on the Virgin Islands boa,
Virgin Islands boas are generally not
present on islands with high densities of
rats. This is likely due to competition
for prey rather than predation.
Reintroductions of Virgin Islands boas
have been successful on islands where
rat populations have been exterminated.
Feral cats are known to prey on boas
and are an ongoing threat to the species.
The fear of snakes, as well as
superstitious beliefs and even confusion
with other snakes, may contribute to the
intentional killing of Virgin Islands boas
(Factor E), although there has not yet
been a systematic study done to
determine if these individual deaths are
having a species-wide effect.
Due to the limited distribution of
Virgin Islands boas, climate change and
SLR (Factor E) may also have an impact.
Low-lying islands and parts of larger
islands, where Virgin Islands boa
populations are supported, are
vulnerable to SLR and storm surge. The
species has persisted despite major
hurricane events, although there may be
impacts to habitat (e.g., die-off of
vegetation) due to storm surge.
The Virgin Islands boa has
demonstrated some ability to adapt to
changing environmental conditions over
time (representation) from both
anthropogenic threats (e.g., habitat
disturbance due to development) and
natural disturbances (e.g., predation and
hurricanes). Since the species was listed
as an endangered species in 1970, it has
demonstrated resiliency despite threats.
Since the writing of the recovery plan
(Service 1986, entire), two new
populations have been reintroduced
(Cayo Ratones and USVI Cay) and two
previously unknown populations have
been discovered (Culebra and Rı´o
Grande), although the continued
persistence of the Cayo Ratones
population is uncertain. There are
currently at least six populations (not
including those potentially on the BVI)
with varying levels of resiliency; one
population has moderately high
resiliency, one has moderate resiliency,
one has moderately low resiliency, and
three have low resiliency. Based on the
biology of the species and the
documented responses to the
development and reintroductions since
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listing, we expect the species to respond
the same way in the foreseeable future.
Our implementing regulations at 50
CFR 424.11(d) set forth a framework
within which we evaluate the
foreseeable future on a case-by-case
basis. The term foreseeable future
extends only so far into the future as the
Services can reasonably determine that
both the future threats and the species’
responses to those threats are likely. In
other words, the foreseeable future is
the period of time in which we can
make reliable predictions. ‘‘Reliable’’
does not mean ‘‘certain’’; it means
sufficient to provide a reasonable degree
of confidence in the prediction. Thus, a
prediction is reliable if it is reasonable
to depend on it when making decisions.
It is not always possible or necessary
to define foreseeable future as a
particular number of years. Analysis of
the foreseeable future uses the best
scientific and commercial data available
and should consider the timeframes
applicable to the relevant threats and to
the species’ likely responses to those
threats in view of its life-history
characteristics. Data that are typically
relevant to assessing the species’
biological response include speciesspecific factors such as lifespan,
reproductive rates or productivity,
certain behaviors, and other
demographic factors.
The foreseeable future described here
uses the best available data and
considers the species’ life-history
characteristics, threat projection
timeframes, and environmental
variability, which may affect the
reliability of projections. We also
considered the timeframes applicable to
the relevant threats and to the species’
likely responses to those threats in view
of its life-history characteristics. We
determined the foreseeable future to be
30 years from present. As discussed
above, the SSA’s future scenarios
considered impacts from development,
habitat restoration and protection,
reintroductions of the Virgin Islands
boa, and SLR. Based on the modeling
and scenarios evaluated for Virgin
Islands boa, we considered our ability to
make reliable predictions in the future
and the uncertainty with regard to how
and to what degree the species would
respond to factors within this
timeframe. In addition, the timing and
response of habitat to restoration efforts
(presumably multiple efforts needed,
and spaced out over time as funding and
resources permit) and the species’
response to those improved habitat
conditions, as well as the lifespan of the
species (which can exceed 20 years in
captivity) also informed our foreseeable
future timeframe.
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Taking into account the impacts of the
factors based on the Status Quo
scenario, and because the Virgin Islands
boa contains three relatively resilient
populations now (i.e., having
moderately high to moderately low
resiliency), and two of those
populations are predicted to maintain
their moderate to moderately high
resiliency in the future, especially in
populations where exotic mammals are
not present, we expect the species to
maintain populations on two of the six
islands within the foreseeable future.
However, continuation of the current
population trends for these two
populations into the future is dependent
on management (e.g., habitat
conservation/preservation and predator
control/eradication). Under the Status
Quo scenario, the three populations on
developed islands are predicted to
possibly become extirpated by 2048.
Under the Conservation Scenario, up to
six populations are predicted to become
highly resilient within the foreseeable
future. While threat intensity and
management needs vary somewhat
across the range of the species (e.g.,
urban population areas versus nonpopulated conserved areas), Virgin
Islands boa populations on islands
throughout the range of the species
continue to be reliant on active
conservation management and require
adequate implementation of regulatory
mechanisms, and all remain vulnerable
to threats that could cause substantial
population declines in the foreseeable
future (e.g., feral cat predation).
Despite the existing regulatory
mechanisms and conservation efforts,
the factors identified above continue to
affect the Virgin Islands boa. However,
the species has persisted with varying
degrees of resiliency since it was listed
in 1970. Once known from three
locations, now known from at least six
locations, the species was successfully
introduced to two new locations (one
possibly extirpated by uncontrolled
exotic mammals) and discovered at two
new locations, and could be at
additional locations in the unsurveyed
BVI and other areas in St. Thomas; thus,
the known distribution has expanded
since listing. Thus, after assessing the
best available information, we
determine that the Virgin Islands boa is
not currently in danger of extinction,
but is likely to become in danger of
extinction within the foreseeable future,
throughout all of its range.
Status Throughout a Significant Portion
of Its Range
Under the Act and our implementing
regulations, a species may warrant
listing if it is in danger of extinction or
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likely to become so within the
foreseeable future throughout all or a
significant portion of its range. The
court in Center for Biological Diversity
v. Everson, 2020 WL 437289 (D.D.C. Jan.
28, 2020) (Center for Biological
Diversity), vacated the aspect of the
2014 Significant Portion of its Range
Policy that provided that the Services
do not undertake an analysis of
significant portions of a species’ range if
the species warrants listing as
threatened throughout all 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
Center for Biological Diversity, we now
consider whether there are any
significant portions of the species’ range
where the species is in danger of
extinction now (i.e., endangered). In
undertaking this analysis for Virgin
Islands boa, we choose to address the
status question first—we consider
information pertaining to the geographic
distribution of both the species and the
threats that the species faces to identify
any portions of the range where the
species is endangered.
For Virgin Islands boa, we considered
whether the threats are geographically
concentrated in any portion of the
species’ range at a biologically
meaningful scale. We examined the
following threats: Habitat loss and
degradation from development,
introduced predators, SLR and a
changing climate, and public attitudes
towards snakes, including cumulative
effects. For detailed descriptions of each
threat, see Summary of Biological Status
and Threats, above.
Impacts from habitat loss and
degradation are prevalent throughout
the range of the Virgin Islands boa. The
boas occur on both privately and
publicly owned land. Habitat loss and
fragmentation from deforestation
happens with the development of
privately owned land, and even occurs
around protected areas. Habitat loss also
happens from SLR. Loss of habitat due
to SLR and storm surge impacts is
similar to loss of habitat due to
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development where the loss of lowlying forest habitat could result in
decreased habitat availability for the
Virgin Islands boas and their prey. All
known islands and cays that are
occupied by Virgin Islands boas are
threatened with habitat loss and
fragmentation.
Similarly, the threat of introduced
predators is of concern range-wide for
the Virgin Islands boa. Feral cats are
known to prey upon boas, and rats may
predate on neonate boas or compete
with boas for prey. Cats and rats are
easily introduced to islands, usually via
boat. Efforts to eliminate exotic
mammalian predators has been
successful on some of the smaller cays,
but requires continual removal and
monitoring on the larger developed
islands.
Climate change is expected to
influence Virgin Islands boa persistence
throughout its range into the future.
Species that are limited in distribution,
such as the Virgin Islands boa, are
susceptible to the impacts of climate
change. Temperatures throughout the
Caribbean are expected to rise,
precipitation is likely to decrease
(resulting in drought), and tropical
storms may occur less frequently but
with more force. Every island and cay
within the range of the Virgin Island boa
is susceptible to these impacts from a
changing climate.
The intentional killing of Virgin
Islands boas is a threat to the species
regardless of where it occurs. While
those boas that live in proximity to
developed areas are more susceptible to
intentional killings, public fear towards
snakes is a threat that can impact the
boas throughout their range.
Low population numbers can be
considered a threat such that the other
threats acting on the species can result
in a concentration of threats to
extremely small populations. Data
presented in the SSA indicate that
current population trend estimates for
Virgin Island boas in Puerto Rico and
USVI are uncertain, indicating that they
are either declining, potentially
declining, considered rare, or unknown,
but most populations are small or
considered rare. Rarity does not
necessarily equate to dangerously small
population sizes, and because the
survey methodologies and reporting has
varied from population to population
and over time, population size and
trend estimates were not exclusively
relied on to determine resiliency.
Despite the rarity of Virgin Island boas
on most islands, the species has
demonstrated resiliency for decades,
and is predicted to continue to maintain
resiliency, despite threats. Therefore
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small population numbers across the
range of the species are not considered
to contribute to a concentration of
threats.
We found no concentration of threats
in any portion of the Virgin Islands
boa’s range at a biologically meaningful
scale. Thus, there are no portions of the
species’ range where the species has a
different status from its rangewide
status. Therefore, no portion of the
species’ range provides a basis for
determining that the species is in danger
of extinction in a significant portion of
its range, and we determine that the
species is likely to become in danger of
extinction within the foreseeable future
throughout all of its range. This is
consistent with the courts’ holdings in
Desert Survivors v. Department of the
Interior, No. 16–cv–01165–JCS, 2018
WL 4053447 (N.D. Cal. Aug. 24, 2018),
and Center for Biological Diversity v.
Jewell, 248 F. Supp. 3d, 946, 959 (D.
Ariz. 2017).
Determination of Status
Our review of the best available
scientific and commercial information
indicates that the Virgin Islands boa
meets the definition of a threatened
species. Therefore, we propose to
reclassify the Virgin Islands boa as a
threatened species in accordance with
sections 3(20) and 4(a)(1) of the Act.
II. Proposed Rule Issued Under Section
4(d) of the Act
Background
Section 4(d) of the Act contains two
sentences. The first sentence states that
the ‘‘Secretary shall issue such
regulations as he deems necessary and
advisable to provide for the
conservation’’ of species listed as
threatened. The U.S. Supreme Court has
noted that statutory language like
‘‘necessary and advisable’’ demonstrates
a large degree of deference to the agency
(see Webster v. Doe, 486 U.S. 592
(1988)). 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.’’ Thus, the combination of the
two sentences of section 4(d) provides
the Secretary with wide latitude of
discretion to select and promulgate
appropriate regulations tailored to the
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specific conservation needs of the
threatened species. The second sentence
grants particularly broad discretion to
the Service when adopting the
prohibitions under section 9.
The courts have recognized the extent
of the Secretary’s discretion under this
standard to develop rules that are
appropriate for the conservation of a
species. For example, courts have
upheld rules developed under section
4(d) as a valid exercise of agency
authority where they prohibited take of
threatened wildlife, or include a limited
taking prohibition (see Alsea Valley
Alliance v. Lautenbacher, 2007 U.S.
Dist. Lexis 60203 (D. Or. 2007);
Washington Environmental Council v.
National Marine Fisheries Service, 2002
U.S. Dist. Lexis 5432 (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 him with regard to the
permitted activities for those species. He
may, for example, permit taking, but not
importation of such species, or he 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).
Exercising our authority under section
4(d), we have developed a speciesspecific proposed rule that is designed
to address the Virgin Islands boa’s
specific threats and conservation needs.
Although the statute does not require
the Service to make a ‘‘necessary and
advisable’’ finding with respect to the
adoption of specific prohibitions under
section 9, we find that this rule taken as
a whole satisfies the requirement in
section 4(d) of the Act to issue
regulations deemed necessary and
advisable to provide for the
conservation of the Virgin Islands boa.
As discussed above under Summary of
Biological Status and Threats, the
Service has concluded that the Virgin
Islands boa is likely to become in danger
of extinction within the foreseeable
future primarily due to developmentassociated impacts (i.e., habitat
fragmentation and loss, vehicular
strikes), predation/competition by
exotic species, climate change, and
persecution by the public. In addition,
the species is management reliant in
that it depends on maintaining current
levels of management and establishing
new populations into suitable habitat.
Therefore, the provisions of this
proposed 4(d) rule would promote
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conservation of the Virgin Islands boa
by encouraging species restoration
efforts. The provisions of this proposed
rule are one of many tools that the
Service would use to promote the
conservation of the Virgin Islands boa.
The proposed 4(d) rule would apply
only if and when the Service makes
final the reclassification of the Virgin
Islands boa as a threatened species.
Provisions of the Proposed 4(d) Rule
The proposed 4(d) rule would provide
for the conservation of the Virgin
Islands boa by prohibiting the following
activities, except as otherwise
authorized or permitted: Import or
export; take; possession and other acts
with unlawfully taken specimens;
delivery, receipt, transport, or shipment
in interstate or foreign commerce in the
course of commercial activity; or sale or
offering for sale in interstate or foreign
commerce. We also propose several
exceptions to these prohibitions, which
along with the prohibitions are set forth
under Proposed Regulation
Promulgation, below.
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 regulation at 50
CFR 17.3. Take can result knowingly or
otherwise, by direct and indirect
impacts, intentionally or incidentally.
Regulating incidental and intentional
take would help preserve the species’
remaining populations, enable
beneficial management actions to occur,
and decrease synergistic, negative
effects from other stressors.
Protecting the Virgin Islands boa from
direct and indirect forms of take, such
as physical injury or killing, whether
incidental or intentional, will help
preserve and recover the remaining
populations of the species. Therefore,
we propose to prohibit intentional and
incidental take of Virgin Islands boa,
including, but not limited to, capturing,
handling, trapping, collecting,
destruction and modification of its
habitat, or any other activities that
would result in take of the species.
As discussed above under Summary
of Biological Status and Threats, a range
of activities have the potential to impact
the species, including development,
intentional killing of boas by private
citizens, and introduction of exotic
predators/competitors (e.g., cats, rats).
Regulating these activities will help
preserve the remaining populations and
protect individual boas.
Protecting the Virgin Islands boa from
incidental take, such as harm that
results from habitat degradation, will
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likewise help preserve the species’
populations and also decrease negative
effects from other stressors impeding
recovery of the species. The species’
continuance may be dependent upon
active management occurring on the
islands and cays, especially as it
concerns exotic predator control and
human development. Most offshore
islands and cays where the Virgin
Islands boa is found are protected by
municipal, territorial, and Federal
agencies. However, existing land
protections provided by those agencies
are not comprehensive for the Virgin
Islands boa and are often not enforced.
We determined that one of the
primary threats to the Virgin Islands boa
is the presence of exotic mammals,
which, when present in high densities,
is indicative of a lack of boa
populations. Therefore, any
introduction of exotic species, such as
cats or rats, that compete with, prey
upon, or destroy the habitat of the
Virgin Islands boa would further impact
the species and its habitat and therefore
will also be prohibited by the proposed
4(d) rule.
Maintaining and expanding existing
populations, and creating new
populations, is also vital to the
conservation of the Virgin Islands boa.
Therefore, the proposed 4(d) rule would
provide for the conservation of the
species by excepting from the take
prohibitions conservation efforts by
Federal, Commonwealth, Territory, and
municipal wildlife agencies to benefit
the Virgin Islands boa, including control
and eradication of exotic mammals,
habitat restoration, and collection of
broodstock, tissue collection for genetic
analysis, captive propagation, and
reintroduction into currently occupied
and unoccupied areas within the
historical range of the species. Efforts by
these wildlife agency entities to monitor
and survey Virgin Islands boa
populations and habitat that require
handling, temporary holding, pit
tagging, tissue sampling, and release
would also be excepted from the take
prohibitions under this proposed 4(d)
rule.
The fear of snakes, as well as
superstitious beliefs, may contribute to
the intentional killing of boas. Although
we cannot address fear or beliefs in a
4(d) rule, we can except from the
prohibitions take associated with
removing boas from houses and other
structures to provide alternatives to
killing individual boas. Therefore, the
proposed 4(d) rule would except from
the prohibitions take associated with
nonlethal removal of Virgin Islands boas
from human structures, and returning
them to natural habitat.
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Even for activities prohibited by the
4(d) rule, including those described
above, we may issue permits to carry
out those activities involving threatened
wildlife under certain circumstances.
Regulations governing permits are
codified at 50 CFR 17.32. With regard to
threatened wildlife, a permit may be
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.
There are also certain statutory
exemptions from the prohibitions,
which are found in sections 9 and 10 of
the Act.
The Service recognizes the special
and unique relationship with our State,
Commonwealth, and Territory natural
resource agency partners in contributing
to conservation of listed species. State,
Commonwealth, and Territory agencies
often possess scientific data and
valuable expertise on the status and
distribution of endangered, threatened,
and candidate species of wildlife and
plants. These agencies, because of their
authorities and their close working
relationships with local governments
and landowners, are in a unique
position to assist the Service in
implementing all aspects of the Act. In
this regard, section 6 of the Act provides
that the Service shall cooperate to the
maximum extent practicable with the
States, Commonwealths, and Territories
in carrying out programs authorized by
the Act. Therefore, any qualified
employee or agent of a Commonwealth
or Territory conservation agency that is
a party to a cooperative agreement with
the Service in accordance with section
6(c) of the Act, who is designated by his
or her agency for such purposes, would
be able to conduct activities designed to
conserve the Virgin Islands boa that may
result in otherwise prohibited take
without additional authorization.
Nothing in this proposed 4(d) rule
would change 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
of the Service to enter into partnerships
for the management and protection of
the Virgin Islands boa. However,
interagency cooperation may be further
streamlined through planned
programmatic consultations for the
species between Federal agencies and
the Service. We ask the public,
particularly Commonwealth and
Territorial agencies and other interested
stakeholders that may be affected by the
proposed 4(d) rule, to provide
comments and suggestions regarding
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additional guidance and methods that
the Service could provide or use,
respectively, to streamline the
implementation of this proposed 4(d)
rule (see Information Requested, above).
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.
to make information available to tribes.
There are no tribal lands associated with
this proposed rule.
Effects of This Proposed Rule
This proposal, if made final, would
revise 50 CFR 17.11 to reclassify the
Virgin Islands boa from endangered to
threatened on the List of Endangered
and Threatened Wildlife. Additionally,
if the proposed 4(d) rule is adopted in
a final rule, the Service will detail
prohibitions set forth at 50 CFR 17.21
and 17.32, except for incidental take
associated with conservation efforts by
Federal, Commonwealth, Territory, or
municipal wildlife agencies; nonlethal
removal from human structures; and
monitoring and survey efforts of Virgin
Islands boa. In addition, we will revise
the List of Endangered and Threatened
Wildlife to change the species’ scientific
name to Chilabothrus granti.
National Environmental Policy Act (42
U.S.C. 4321 et seq.)
It is our position that, outside the
jurisdiction of the U.S. Court of Appeals
for the Tenth Circuit, we do not need to
prepare environmental analyses
pursuant to the National Environmental
Policy Act (NEPA; 42 U.S.C. 4321 et
seq.) in connection with designating
critical habitat under the Act. We
published a notice outlining our reasons
for this determination in the Federal
Register on October 25, 1983 (48 FR
49244). This position was upheld by the
U.S. Court of Appeals for the Ninth
Circuit (Douglas County v. Babbitt, 48
F.3d 1495 (9th Cir. 1995), cert. denied
516 U.S. 1042 (1996)).
A complete list of references cited is
available on the internet at https://
www.regulations.gov under Docket No.
FWS–R4–ES–2019–0069 and upon
request from the Field Supervisor,
Caribbean Ecological Services Field
Office (see FOR FURTHER INFORMATION
CONTACT, above).
Required Determinations
Clarity of the Proposed Rule
We are required by Executive Orders
12866 and 12988 and by the
Presidential Memorandum of June 1,
1998, to write all rules in plain
language. This means that each rule we
publish must:
(a) Be logically organized;
(b) Use the active voice to address
readers directly;
(c) Use clear language rather than
jargon;
(d) Be divided into short sections and
sentences; and
(e) 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
Common name
Scientific name
*
Reptiles
*
jbell on DSKJLSW7X2PROD with PROPOSALS
*
Boa, Virgin Islands tree ..
*
*
*
Chilabothrus granti ........
*
*
Special rules—reptiles.
*
VerDate Sep<11>2014
*
*
16:31 Sep 29, 2020
Jkt 250001
*
Fmt 4702
List of Subjects in 50 CFR Part 17
Endangered and threatened species,
Exports, Imports, Reporting and
recordkeeping requirements,
Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend
part 17, subchapter B of chapter I, title
50 of the Code of Federal Regulations,
as set forth below:
PART 17—ENDANGERED AND
THREATENED WILDLIFE AND PLANTS
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.
§ 17.11 Endangered and threatened
wildlife.
2. Amend § 17.11 in paragraph (h) by
revising the entry for ‘‘Boa, Virgin
Islands tree’’ under REPTILES in the
List of Endangered and Threatened
Wildlife to read as follows:
■
*
*
Wherever found ............
Frm 00077
The primary authors of this proposed
rule are staff members of the Service’s
Species Assessment Team and the
Caribbean Ecological Services Field
Office.
Listing citations and
applicable rules
*
T
*
Sfmt 4702
*
*
*
35 FR 16047, 10/13/1970; 44 FR 70677, 12/7/
1979; [Federal Register citation of the final
rule]. 50 CFR 17.42(j).4d
*
(j) Virgin Islands tree boa
(Chilabothrus granti)—(1) Prohibitions.
The following prohibitions that apply to
endangered wildlife also apply to Virgin
PO 00000
Authors
Status
*
*
3. Amend § 17.42 by adding paragraph
(j) to read as set forth below:
*
Where listed
*
■
§ 17.42
Government-to-Government
Relationship With Tribes
In accordance with the President’s
memorandum of April 29, 1994,
‘‘Government-to-Government Relations
with Native American Tribal
Governments’’ (59 FR 22951), Executive
Order 13175, and the Department of the
Interior’s manual at 512 DM 2, we
readily acknowledge our responsibility
to communicate meaningfully with
recognized Federal Tribes on a
government-to-government basis. In
accordance with Secretarial Order 3206
of June 5, 1997 (American Indian Tribal
Rights, Federal-Tribal Trust
Responsibilities, and the Endangered
Species Act), we readily acknowledge
our responsibilities to work directly
with tribes in developing programs for
healthy ecosystems, to acknowledge that
tribal lands are not subject to the same
controls as Federal public lands, to
remain sensitive to Indian culture, and
References Cited
*
*
Islands tree boa. Except as provided
under paragraph (j)(2) of this section
and §§ 17.4 and 17.5, it is unlawful for
any person subject to the jurisdiction of
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jbell on DSKJLSW7X2PROD with PROPOSALS
the United States to commit, to attempt
to commit, to solicit another to commit,
or cause to be committed, any of the
following activities in regard to this
species:
(i) Import or export, as set forth at
§ 17.21(b);
(ii) Take, as set forth at § 17.21(c)(1);
(iii) Possession and other acts with
unlawfully taken specimens, as set forth
at § 17.21(d)(1);
(iv) Interstate or foreign commerce in
the course of commercial activity, as set
forth at § 17.21(e); and
(v) Sale or offer for sale, as set forth
at § 17.21(f).
(vi) The intentional or incidental
introduction of exotic species, such as
cats or rats, that compete with, prey
VerDate Sep<11>2014
16:31 Sep 29, 2020
Jkt 250001
upon, or destroy the habitat of the
Virgin Islands boa is also prohibited.
(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 endangered
wildlife, as set forth at § 17.21(d)(2).
(v) Incidental take of Virgin Islands
tree boa resulting from:
(A) Conservation efforts by Federal,
Commonwealth, Territory, or municipal
wildlife agencies, including, but not
limited to, control and eradication of
exotic mammals and habitat restoration,
and collection of broodstock, tissue
PO 00000
Frm 00078
Fmt 4702
Sfmt 9990
61717
collection for genetic analysis, captive
propagation, and reintroduction into
currently occupied or unoccupied areas
within the historical range of the Virgin
Islands tree boa.
(B) Nonlethal removal (and return to
natural habitat) of Virgin Islands tree
boa from human structures, defense of
human life, and authorized capture and
handling of Virgin Islands tree boas.
(C) Efforts to monitor and survey
Virgin Islands tree boa populations and
habitat that may include handling,
temporary holding, pit tagging, tissue
sampling, and release.
Aurelia Skipwith,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2020–19027 Filed 9–29–20; 8:45 am]
BILLING CODE 4333–15–P
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]]>Agencies
[Federal Register Volume 85, Number 190 (Wednesday, September 30, 2020)]
[Proposed Rules]
[Pages 61700-61717]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-19027]
-----------------------------------------------------------------------
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2019-0069; FXES11130900000-189-FF0932000]
RIN 1018-BE14
Endangered and Threatened Wildlife and Plants; Reclassifying the
Virgin Islands Tree Boa From Endangered to Threatened With a Section
4(d) Rule
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to
reclassify the Virgin Islands tree boa (Virgin Islands boa;
Chilabothrus (= Epicrates) granti) from an endangered species to a
threatened species with a rule issued under section 4(d) of the
Endangered Species Act of 1973 (Act), as amended. If we finalize this
rule as proposed, it would reclassify the Virgin Islands boa from
endangered to threatened on the List of Endangered and Threatened
Wildlife (List). This proposal is based on a thorough review of the
best available scientific data, which indicate that the species' status
has improved such that it is not currently in danger of extinction
throughout all or a significant portion of its range. We are also
proposing a rule under the authority of section 4(d) of the Act that
provides measures that are necessary and advisable to provide for the
conservation of the Virgin Islands boa. Further, we are correcting the
List to change the scientific name of the Virgin Islands boa in the
List from Epicrates monensis granti to Chilabothrus granti to reflect
the currently accepted taxonomy. Virgin Islands boa is a distinct
species, not a subspecies, and Epicrates is no longer the
scientifically accepted genus for this species.
DATES: We will accept comments received or postmarked on or before
November 30, 2020. Comments submitted electronically using the Federal
eRulemaking Portal (see ADDRESSES, below) must be received by 11:59
p.m. Eastern Time on the closing date. We must receive requests for a
public hearing, in writing, at the address shown in FOR FURTHER
INFORMATION CONTACT by November 16, 2020.
ADDRESSES: Written comments: You may submit comments on this proposed
rule 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-2019-0069,
which is the docket number for this rulemaking. Then, click on the
Search button. On the resulting page, in the Search panel on the left
side of the screen, under the Document Type heading, click on the
Proposed Rule box to locate this document. You may submit a comment by
clicking on ``Comment Now!''
(2) By hard copy: Submit by U.S. mail to: Public Comments
Processing, Attn: FWS-R4-ES-2019-0069; U.S. Fish and Wildlife Service,
MS: JAO/1N, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
We request that you send comments only by the methods described
above. We will post all comments on https://www.regulations.gov. This
generally means that we will post any personal information you provide
us (see Information Requested, below, for more information).
Document availability: The proposed rule and supporting documents
(including the species status assessment (SSA) report and references
cited) are available at https://www.regulations.gov under Docket No.
FWS-R4-ES-2019-0069.
FOR FURTHER INFORMATION CONTACT: Edwin E. Mu[ntilde]iz, Field
Supervisor, U.S. Fish and Wildlife Service, Caribbean Ecological
Services Field Office, Road 301 Km 5.1, Corozo Ward, Boquer[oacute]n,
Puerto Rico 00622; or P.O. Box 491, Boquer[oacute]n, Puerto Rico 00622;
telephone 787-851-7297. Persons who use a telecommunications device for
the deaf (TDD) may call the Federal Relay Service at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, a species may warrant
reclassification from endangered to threatened if it no longer meets
the definition of endangered (in danger of extinction). The Virgin
Islands boa is listed as endangered, and we are proposing to reclassify
it as threatened because we have determined it is no longer in danger
of extinction. Reclassifications can only be made by issuing a rule.
Furthermore, extending the ``take'' prohibitions in section 9 of the
Act to threatened species, such as those we are proposing for this
species under a section 4(d) rule, can only be made by issuing a rule.
Finally, the change of the scientific name of the Virgin Islands boa in
the List from Epicrates monensis granti to Chilabothrus granti, can
only be made effective by issuing a rule.
[[Page 61701]]
What this rule does. We propose to reclassify the Virgin Islands
tree boa from an endangered species to a threatened species with a rule
issued under section 4(d) of the Act to provide measures that are
necessary and advisable to provide for the conservation of this
species. We also change the scientific name in the List to reflect the
currently accepted taxonomy.
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 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 Virgin Islands boa is
not currently in danger of extinction and, therefore, does not meet the
definition of an endangered species, but is still affected by the
following current and ongoing stressors to the extent that the species
meets the definition of a threatened species under the Act:
Habitat loss and fragmentation from human development
(Factor A).
Direct and indirect predation/competition by exotic
mammals such as rats, cats, and possibly, to a lesser extent, mongoose
(Factor C).
Stochastic events such as hurricanes and sea level rise,
exacerbated by the cumulative effects of climate change (Factor E).
Intentional harm due to fear of snakes (Factor E).
We are also proposing a section 4(d) rule. When we list a species
as threatened, section 4(d) of the Act allows us to issue regulations
that are necessary and advisable to provide for the conservation of the
species. Accordingly, we are proposing a 4(d) rule for the Virgin
Islands boa that would, among other things, prohibit take associated
with capturing, handling, trapping, collecting, or other activities,
including intentional or incidental introduction of exotic species,
such as cats or rats that compete with, prey upon, or destroy the
habitat of the Virgin Islands boa. The proposed 4(d) rule would also
except from these prohibitions take associated with certain
conservation efforts.
Peer review. In accordance with our joint policy on peer review
published in the Federal Register on July 1, 1994 (59 FR 34270), and
our August 22, 2016, memorandum updating and clarifying the role of
peer review of listing actions under the Act, we sought the expert
opinions of six appropriate specialists regarding the species status
assessment report (SSA). We received responses from five specialists on
the SSA report, which informed this proposed rule. The purpose of peer
review is to ensure that our listing determinations, critical habitat
designations, and 4(d) rules are based on scientifically sound data,
assumptions, and analyses. The peer reviewers have expertise in the
biology, habitat, and threats to the species.
Because we will consider all comments and information we receive
during the comment period, our final determination may differ from this
proposal. Based on the new information we receive (and any comments on
that new information), we may conclude that the species is endangered
instead of threatened, or we may conclude that the species does not
warrant listing as either an endangered species or a threatened
species. Such final decisions would be a logical outgrowth of this
proposal, as long as we: (1) Base the decisions on the best scientific
and commercial data available, after considering all of the relevant
factors; (2) do not rely on factors Congress has not intended us to
consider; and (3) articulate a rational connection between the facts
found and the conclusions made, including why we changed our
conclusion.
Information Requested
We intend that any final action resulting from this 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 and information from other concerned governmental agencies,
Native American tribes, the scientific community, industry, or any
other interested party concerning this proposed rule.
We particularly seek comments on:
(1) Information concerning the biology and ecology of the Virgin
Islands boa.
(2) Relevant data concerning any stressors (or lack thereof) to the
Virgin Islands boa, particularly any data on the possible effects of
climate change as it relates to habitat, and the extent of Territorial
protection and management that would be provided to this boa as a
threatened species.
(3) Reasons why we should or should not reclassify the Virgin
Islands boa from an endangered species to a threatened species under
the Act.
(4) Information concerning activities that should be considered
under a rule issued in accordance with section 4(d) of the Act (16
U.S.C. 1531 et seq.) as a prohibition or exception within U.S.
territory that would contribute to the conservation of the species. In
particular, we are seeking input from experts regarding species
restoration and captive propagation practices and related activities,
or whether take associated with any other activities should be
considered excepted from the prohibitions in the 4(d) rule.
(5) Current or planned activities within the geographic range of
the Virgin Islands boa that may either negatively impact or benefit the
species.
Please include sufficient information with your submission (such as
scientific journal articles or other publications) to allow us to
verify any scientific or commercial information you include.
Please note that submissions merely stating support for, or
opposition to, the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is an endangered or a
threatened species must be made ``solely on the basis of the best
scientific and commercial data available.''
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in ADDRESSES. We request that you
send comments only by the methods described in ADDRESSES.
If you submit information via https://www.regulations.gov, your
entire submission--including any personal identifying information--will
be posted on the website. If your submission is made via a hardcopy
that includes personal identifying information, you may request at the
top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so. We
will post all hardcopy submissions on 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, or by
appointment, during normal business hours, at the U.S. Fish and
Wildlife Service, Caribbean Ecological Services Field Office (see FOR
FURTHER INFORMATION CONTACT).
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
[[Page 61702]]
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 at least 15 days before the
hearing. For the immediate future, we will provide these public
hearings using webinars that will be announced on the Service's
website, in addition to the Federal Register. The use of these virtual
public hearings is consistent with our regulation at 50 CFR
424.16(c)(3).
Previous Federal Actions
The Virgin Islands boa was originally listed as an endangered
subspecies (Epicrates inornatus granti) of the Puerto Rican boa
(Epicrates inornatus at time of listing, now Chilabothrus inornatus) on
October 13, 1970 (35 FR 16047), under the Endangered Species
Conservation Act of 1969, and remained listed with the passage of the
Act in 1973. In 1979, we published a technical correction (44 FR 70677,
December 7, 1979) revising the scientific name of the Virgin Islands
boa from Epicrates inornatus granti to Epicrates monensis granti. A
recovery plan for this species was completed in 1986 (Service 1986,
entire) and updated in September 2019. The most recent 5-year review,
completed in 2009, recommended reclassifying the Virgin Islands boa to
a threatened species due to the population stabilizing (Service 2009,
entire). Based on this recommendation, we initiated a species status
assessment (SSA) and completed an SSA report in 2018 (Service 2018,
entire).
Supporting Documents
A species status assessment (SSA) team prepared an SSA report for
the Virgin Islands boa. The SSA team was composed of Service
biologists, in consultation with other species experts. The SSA report
represents a compilation of the best scientific and commercial data
available concerning the status of the species, including the impacts
of past, present, and future factors (both negative and beneficial)
affecting the species. The Service sent the SSA report to six
independent peer reviewers and received five responses. The Service
also sent the SSA report to state partners, including scientists with
expertise in Virgin Islands boa habitat, for review. We received review
from two experts from the Puerto Rico Department of Natural and
Environmental Resources.
I. Proposed Reclassification Determination
Background
A thorough review of the taxonomy, life history, ecology, and
overall viability of the Virgin Islands boa is presented in the SSA
report (Service 2018, entire; available at https://www.fws.gov/southeast/ and at https://www.regulations.gov under Docket No. FWS-R4-
ES-2019-0069). A summary of this information follows:
The Virgin Islands boa is endemic to Puerto Rico and the Virgin
Islands (U.S. and British). Originally, the Virgin Islands boa was
considered a subspecies of the Puerto Rican boa (Epicrates inornatus;
Stull 1933, pp. 1-2), but was later found to be more closely related to
the Mona Island boa, and the nomenclature for the two snakes was
altered to reflect two subspecies, Epicrates monensis monensis (Mona
Island boa) and E. m. granti (Virgin Islands boa) (Sheplan and Schwartz
1974, pp. 94-104). More recently, molecular phylogeny work indicates
that the genus Epicrates is paraphyletic (a group composed of a
collection of organisms, including the most recent common ancestor of
all those organisms), and the West Indian clade (as opposed to the
mainland clade) was designated as Chilabothrus (Reynolds et al. 2013,
entire). As a result, the Virgin Islands boa is now considered its own
species. We accept the change of the Virgin Islands boa's
classification from the subspecies Epicrates monensis granti to the
species Chilabothrus granti and are amending the scientific name to
match the currently accepted nomenclature.
The Virgin Islands boa is a medium-length, slender, nonvenomous
snake. The largest snout-vent lengths (SVL) recorded for the species
were 1,066 millimeters (mm; 42 inches (in)) for females and 1,112 mm
(44 in) for males (total body lengths 1,203 mm (47 in) and 1,349 mm (53
in), respectively; Tolson 2005, entire), although most specimens range
between 600 and 800 mm (24-31 in) SVL, with an average mass of 165
grams (6 ounces) (USVI Division of Wildlife, unpub. data). Adults are
gray-brown with dark-brown blotches that are partially edged with
black, and feature a blue-purple iridescence on their dorsal surface;
the ventral surface is creamy white or yellowish white. Newborns, on
the other hand, have an almost grayish-white body color with black
blotches and weigh 2.0-7.2 grams (0.07-0.25 ounces) with SVLs of 200-
350 mm (approx. 8-14 inches) (Tolson 1992, pers. comm.).
The Virgin Islands boa occurs in subtropical dry forest and
subtropical moist forest (Service 2009, p. 11). Subtropical dry forest
covers approximately 14 percent (128,420 hectares (ha); 317,332 acres
(ac)) of Puerto Rico and the U.S. Virgin Islands (USVI), typically
receives less than 750 mm (29 in) rainfall annually (Ewel and Whitmore
1973, pp. 9-20), and is characterized by small (less than 5 meter (m;
16 feet (ft)) deciduous trees with high densities of interlocking
branches and vines connecting adjacent tree canopies (Ewel and Whitmore
1973, p. 10). Subtropical moist forest covers approximately 58 percent
(538,130 ha; 1,329,750 acres) of Puerto Rico and USVI and typically
receives more than 1,100 mm (43 in) of annual rainfall. It is dominated
by semi-evergreen and evergreen deciduous trees up to 20 m (66 ft) tall
with rounded crowns. The Virgin Islands boa has also been reported to
occur in mangrove forest, thicket/scrub, disturbed lower vegetation,
and artificial structures (Harvey and Platenberg 2009, p. 114; Tolson
2003, entire).
Habitat needs for Virgin Islands boa can be divided into those for
foraging and those for resting. Factors contributing to foraging
habitat quality are tree density and connectivity, presence of arboreal
and ground-level refugia, prey density, and rat presence/density
(Tolson 1988, pp. 234-235). Tree density is more important than tree
species or diversity; Virgin Islands boas do not appear to prefer a
particular tree species after accounting for availability and structure
(Platenberg 2018, pers. comm.). The highest densities of Virgin Islands
boas are found where there are few or no exotic predators and high
densities of lizard prey (Tolson 1988, p. 233; Tolson 1996b, p. 410).
Resting habitat includes refugia for inactive boas to use during the
day. Refugia can be the axils (angles between trunk and branches) of
Cocos or Sabal species, tree holes, termite nests, or under rocks and
debris (Tolson 1988, p. 233).
The Virgin Islands boa forages at night by gliding slowly along
small branches in search of sleeping lizards (Service 1986, p. 6). The
primary prey for the Virgin Islands boa is the Puerto Rican crested
anole (Anolis cristatellus), and the greatest concentrations of Virgin
Islands boa are found where Anolis densities exceed 60 individuals/100
m\2\ (1,076 ft\2\; Tolson 1988, p. 233). Other prey species include
ground lizard (Ameiva exsul), house mouse (Mus musculus), small birds,
iguana (Iguana iguana) hatchlings, and likely other small animals
encountered (Maclean 1982, pp. 30-31, 37; Tolson 1989, p.
[[Page 61703]]
165; Tolson 2005, p. 9; Platenberg 2018, pers. comm.). The Virgin
Islands boa may also compete for prey and other niche components with
the Puerto Rican racer (Borikenophis portoricensis), a snake native to
Puerto Rico, the U.S. and British Virgin Islands, and surrounding cays.
Much of what is known about Virgin Islands boa life history comes
from studies in captivity. Lifespans in captivity often exceed 20
years, and sometimes exceed 30 years (7% of captive Virgin Islands boas
exceeded 30 years of age; Smith 2018, pers. comm.), but typical
lifespans in the wild are not known. Sexual maturity is reached at 2-3
years of age (Tolson 1989, Tolson and Pi[ntilde]ero 1985), and boas are
still reproductive at >20 years of age (Tolson 2018, pers. comm.).
Females breed biennially, but studies have suggested that annual
breeding may occur in some conditions (Tolson and Pi[ntilde]ero 1985).
Courtship behaviors and copulation occur from February through May, and
interaction with conspecifics of the opposite sex appears to be
necessary for reproductive cycling (Tolson 1989). The gestation period,
observed from a single known copulation between two individuals, is
about 132 days (Tolson 1989). Virgin Islands boas give birth to live
young from late August through October to litters of 2-10 young, and
litter size increases with female body size (Tolson 1992, pers. comm.).
The exact historical distribution of the Virgin Islands boa is
unknown, but its present disjointed distribution suggests that it was
once more widely distributed across small islands within its range. In
the 1970s, when the Virgin Islands boa was originally listed, its range
was identified as three islands: Puerto Rico (no specific site), St.
Thomas, USVI (from a single record), and Tortola in the British Virgin
Islands (BVI) (from one report) (44 FR 70677, December 7, 1979). When
the recovery plan was written (1986), 71 individuals were reported in
two populations: one on the eastern side of St. Thomas in the USVI, and
one at Cayo Diablo, an offshore islet in Puerto Rico (Service 2009).
Currently, the Virgin Islands boa occurs on six islands between
Puerto Rico, USVI, and BVI: the eastern Puerto Rican islands of Cayo
Diablo and Culebra; R[iacute]o Grande on the Puerto Rican main island;
eastern St. Thomas and an offshore cay in USVI (USVI Cay; an introduced
population); and Tortola. A seventh population (also introduced) on the
Puerto Rican island of Cayo Ratones may still remain, although after
the reestablishment of rats on this island after 2004, the status of
this population is uncertain (Service 2018, p. 24). A recent survey did
not find Virgin Islands boas on Cayo Ratones in 2018 (Island
Conservation 2018, pp. 5, 17). However, because Virgin Islands boas are
difficult to find, and the 2018 surveys were not extensive (e.g., did
not survey the whole island), there is currently not enough evidence to
conclude the Cayo Ratones population has been extirpated. Lastly, there
is also one report from 2004 that the species occurs on Greater St.
James Island in St. Thomas, but nothing is known about that potential
population (Dempsey 2019, pers. comm.). In 2009, based on all known
populations in Puerto Rico and the USVI, an estimated 1,300-1,500
Virgin Islands boas were thought to occur (Service 2009, p. 8),
although many population sizes used for this estimate are highly
speculative. Based on the 2018 SSA (Service 2018, entire), current
population trend estimates for Puerto Rico and USVI are either
declining, potentially declining, considered rare, or unknown and most
populations are small or considered rare (Service 2018, p. 30).
The population in Tortola Island, BVI, was confirmed in 2018, but
there are no specific data regarding the status of that population
(McGowan 2018, pers. comm.). In addition, according to anecdotal
reports, the species is thought to occur on Jost Van Dyke, Guana
Island, Necker Cay, Great Camanoe, and Virgin Gorda of the BVI (Mayer
and Lazell 1988, entire), but data and confirmed observations are
limited. There is not enough information to reliably assess the status
of Virgin Islands boa populations on those islands.
Regulatory and Analytical Framework
Regulatory Framework
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 is an ``endangered species'' or a ``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 expected response by the species,
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 now and in
the foreseeable future.
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
[[Page 61704]]
future on a case-by-case basis. The term foreseeable future extends
only so far into the future as the Services can reasonably determine
that both the future threats and the species' responses to those
threats are likely. In other words, the foreseeable future is the
period of time in which we can make reliable predictions. ``Reliable''
does not mean ``certain''; it means sufficient to provide a reasonable
degree of confidence in the prediction. Thus, a prediction is reliable
if it is reasonable to depend on it when making decisions.
It is not always possible or necessary to define foreseeable future
as a particular number of years. Analysis of the foreseeable future
uses the best scientific and commercial data available and should
consider the timeframes applicable to the relevant threats and to the
species' likely responses to those threats in view of its life-history
characteristics. Data that are typically relevant to assessing the
species' biological response include species-specific factors such as
lifespan, reproductive rates or productivity, certain behaviors, and
other demographic factors.
Analytical Framework
The SSA report documents the results of our comprehensive
biological status review for the species, including an assessment of
the potential threats to the species. The SSA report does not represent
a decision by the Service on whether the species should be proposed for
listing as an endangered or threatened species under the Act. It does,
however, 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. The following is
a summary of the key results and conclusions from the SSA report; the
full SSA report can be found at Docket FWS-R4-ES-2019-0069 on https://www.regulations.gov and at https://www.fws.gov/southeast/.
To assess the Virgin Islands boa's viability, we used the three
conservation biology principles of resiliency, redundancy, and
representation (Shaffer and Stein 2000, pp. 306-310). Briefly,
resiliency supports the ability of the species to withstand
environmental and demographic stochasticity (for example, wet or dry,
warm or cold years), redundancy supports the ability of the species to
withstand catastrophic events (for example, droughts, large pollution
events), and representation supports the ability of the species to
adapt over time to long-term changes in the environment (for example,
climate changes). In general, the more resilient and redundant a
species is and the more representation it has, the more likely it is to
sustain populations over time, even under changing environmental
conditions. 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. This process used the best
available information to characterize viability as the ability of a
species to sustain populations in the wild over time. We use this
information to inform our regulatory decision.
Summary of Biological Status and Threats
In this discussion, we review the biological condition of the
species and its resources, and the threats that influence the species'
current and future condition, in order to assess the species' overall
viability and the risks to that viability. In the SSA report (Service
2018, pp. 12-18), we reviewed all factors (i.e., threats, stressors)
that could be affecting the Virgin Islands boa now or in the future.
However, in this proposed rule, we will focus our discussion only on
those factors that could meaningfully impact the status of the species.
The risk factors affecting the status of the Virgin Islands boa vary
from location to location, but generally include habitat loss and
degradation from development, introduced predators, sea level rise
(SLR) and a changing climate, and public attitudes towards snakes.
Where habitat is available but the species is not present (i.e., most
of the small islands in the eastern Puerto Rico bank and USVI), it is
believed that absences are due to local extirpation resulting from
habitat degradation and colonization of exotic species (Service 2009,
p. 11). We discuss each of the risk factors below.
Development
Virgin Islands boas occur on both privately and publicly owned
land. Virgin Islands boas have been observed living in developed areas
around residences and can persist within developed areas if habitat
patches are available, but only if no cats or rats are around
(Platenberg and Harvey 2010, p. 552; Platenberg 2018, pers. comm.).
Where boas coexist with urban development, development continues to
threaten populations via habitat destruction, especially in St. Thomas,
R[iacute]o Grande (Puerto Rico), and Culebra Island where habitat has
declined throughout decades. In St. Thomas, available habitat has
declined due to development for resorts, condos, and related
infrastructure, and has become more constricted and isolated
(Platenberg and Harvey 2010, p. 552). In Puerto Rico, human populations
are decreasing, but residential development continues to increase
island-wide, including around protected areas (Castro-Prieto et al.
2017, entire). Consequences of human development on the boa and its
habitat not only include habitat loss and fragmentation due to
deforestation, but also mortality from vehicular strikes, an increase
in predators such as cats and rats, and an increase in human-boa
conflicts that results in snakes being killed because of fear of snakes
(Service 2018, pp. 13-14).
Both Puerto Rico and the USVI have regulatory mechanisms
established to protect the species and its habitat throughout
consultation processes for the authorization of development projects.
Presently, the Virgin Islands boa is legally protected under Puerto
Rico's Commonwealth Law No. 241-1999 (12 L.P.R.A. Sec.107), known as
the New Wildlife Law of Puerto Rico. This law has provisions to protect
habitat for all wildlife species, including plants and animals. In
addition, the species is protected by Puerto Rico Department of Natural
and Environmental Resources (PRDNER)'s Regulation 6766, which under
Article 2.06 prohibits collecting, cutting, and removing, among other
activities, listed plant and animal individuals within the jurisdiction
of Puerto Rico (DRNA 2004). In USVI, Act No. 5665, known as the Virgin
Islands' Indigenous and Endangered Species Act, which is enforced by
the U.S. Virgin Islands Department of Planning and Natural Resources
(VIDPNR), protects the species.
Despite these regulations being in place, including the requirement
for developers to conduct environmental assessments and mitigate damage
to the species and habitat, the regulations have proved difficult to
enforce, they are often ignored by developers, and they do not cover
all development activities in all Virgin Islands boa habitat
(Platenberg 2011, pers. comm.). For
[[Page 61705]]
example, in St. Thomas, major permit applications submitted for
projects in the coastal zone require an environmental impact assessment
that addresses endangered species and protected habitat, but these
requirements do not apply to smaller projects or those outside of the
coastal zone. Furthermore, as noted in one study, even though a
protocol was developed and applied to delineate habitat on protected
sites and identify mitigation strategies, the absence of a legal
mechanism to enforce mitigation has led to varying success as
developers are slow to accept, and often ignore, the mitigation process
(Platenberg and Harvey 2010, pp. 551-552).
Most offshore cays within the species' range are part of the
Territorial Government or protected as wildlife refuges, thus formally
protecting Virgin Islands boa habitat for three of the six populations
(i.e., Cayo Diablo, Cayo Ratones, and USVI Cay). Cayo Ratones and Cayo
Diablo are included in La Cordillera Natural Reserve managed by the
PRDNER, and the offshore cay in USVI is managed and protected by the
VIDPNR. Furthermore, even though Virgin Islands boa habitat on
privately owned land on Culebra Island is currently under pressure from
urban and tourism development and deforestation, more than 1,000 acres
of suitable habitat on the island are protected within the Service's
Culebra National Wildlife Refuge.
Predation and Competition
One of the primary threats to Virgin Islands boa populations is
predation by exotic mammalian predators, mainly cats and rats, and
possibly, to a lesser degree, mongoose. Mongoose are not likely a major
predator of Virgin Islands boa because mongoose are terrestrial and
active during the day, while Virgin Islands boas are arboreal and
active primarily at night, although not exclusively (Service 2018, p.
14). Feral cats are known to prey upon boas (Tolson 1996b, p. 409), and
cat populations around human development are further bolstered by cat
feeding stations set up by residents. There has not been direct
evidence of rats preying upon Virgin Islands boas, but boas are not
present on islands with high densities of rats (Tolson 1986,
unpaginated; Tolson 1988, p. 235). Rats likely negatively impact Virgin
Islands boas by competing for prey, or by inducing behavioral changes
in Anolis prey that make them less likely to be encountered by boas
(Tolson 1988, p. 235). However, rats may also predate on neonate boas
(Service 1986, p. 12). Complete predator removal on large developed
islands is challenging, but is feasible on smaller cays. Prior to
reintroduction of the boas, rats were eliminated from Cayo Ratones and
the USVI Cay using anticoagulant poison (Tolson 1996b, p. 410),
although Cayo Ratones was recolonized by rats sometime after August
2004, highlighting the importance of ongoing monitoring for rat
presence after a removal project. Cayo Ratones was thought to harbor
one of the most robust Virgin Islands boa populations, but during the
recent 2018 survey, no boas were found (Island Conservation 2018, p.
20). There are no Virgin Islands boas present on islands with
established rat populations and no rat predators (such as cats).
Effects of Climate Change, Including Sea Level Rise
Climate change will continue to influence Virgin Islands boa
persistence into the future. Species that are dependent on specialized
habitat types or limited in distribution (including the Virgin Islands
boa) are most susceptible to the impacts of climate change (Byers and
Norris 2011, p. 22).
The climate in the southeastern United States and Caribbean has
warmed about two degrees Fahrenheit from a cool period in the 1960s and
1970s, and temperatures are expected to continue to rise (Carter et al.
2014, pp. 398-399). Projections for future precipitation trends in this
area are less certain than those for temperature, but suggest that
overall annual precipitation will decrease, and that tropical storms
will occur less frequently but with more force (i.e., more category 4
and 5 hurricanes) than historical averages (Carter et al. 2014, pp.
398-399; Knutson et al. 2010, pp. 161-162). With increasing
temperatures and decreasing precipitation, drought could negatively
influence Virgin Islands boa populations. After a severe drought in
eastern Puerto Rico, Anolis populations crashed on Cayo Diablo and body
condition indices of the boas plummeted (Tolson 2018, pers. comm.).
Sea levels are expected to rise globally, potentially exceeding 1 m
(3 feet) of SLR by 2100 (Reynolds et al. 2012, p. 3). Local SLR impacts
will depend not only on how much the ocean level itself rises, but also
on land subsidence or changes in offshore currents (Carter et al. 2014,
p. 400). Impacts on terrestrial ecosystems can be temporary, via
submergence of habitat during storm surges, or permanent, via salt
water intrusion into the water table, inundation of habitat, and
erosion. SLR and hurricane storm surges in the Caribbean are predicted
to inundate low-lying islands and parts of larger islands (Bellard et
al. 2014, pp. 203-204). The low-lying islands of Cayo Diablo and the
USVI Cay, which support Virgin Islands boa populations, and the island
of Cayo Ratones, which may still support a population, are all
vulnerable to SLR and storm surges in the future. Boa populations on
R[iacute]o Grande, Culebra, and St. Thomas are not considered at risk
from SLR; however, the three cays (Cayo Diablo, Cayo Ratones, and USVI
Cay) could see 10-23 percent loss due to SLR over the next 30 years
(Service 2018, pp. 38-46). Past and current observations suggest that
the species can survive major hurricane events, although lasting
impacts to habitat, particularly die-off of vegetation inundated by
storm surges, have been observed (Platenberg 2018, pers. comm.; Smith
2018, unpaginated; Tolson 1991, pp. 12, 16; Yrigoyen 2018, pers.
comm.). Loss of habitat due to storm surge impacts is similar to loss
of habitat due to development; loss of low-lying forest habitat could
result in decreased habitat availability for the Virgin Islands boas
and their prey.
Persecution by Residents
Intentional killing of the more common and larger sized Puerto
Rican boa (Chilabothrus inornatus) due to fear or superstitious beliefs
has been well documented in the literature (Bird-Pic[oacute] 1994, p.
35; Puente-Rol[oacute]n and Bird-Pic[oacute] 2004, p. 343; Joglar 2005,
p. 146). Thus, Virgin Islands boas in proximity to developed areas
where people fear snakes are susceptible to intentional killings.
Public encounters with Virgin Islands boas in the more populated
R[iacute]o Grande and Culebra locations are considered questionable
because of the rarity of boas in those populations, and there are only
a couple of anecdotal records of intentional killings between those
areas (Service 2009, pp. 15-16). In the highly developed east side of
St. Thomas, about 10 percent of the Virgin Islands boa records in St.
Thomas are from dead boas killed by humans on private property
(Platenberg 2006, unpub. data). We have no further information to
assess the magnitude of this threat, but it is likely that intentional
killings of Virgin Islands boas still occur, are not being documented,
and would be particularly detrimental to rare populations such as in
R[iacute]o Grande. The Service is not aware of a law enforcement case
related to the boa in Puerto Rico or the USVI. Populations that occur
within protected areas are not expected to be exposed to this threat.
[[Page 61706]]
Conservation Measures That Affect the Species
Positive influences on Virgin Islands boa viability have been
habitat protection, predator control, and captive breeding and
reintroduction. Two populations of Virgin Islands boa were reintroduced
to protected cays after predators had been removed, one on Cayo Ratones
(Puerto Rico) in 1993, and another on USVI Cay in 2002. Founders for
these reintroductions came largely from a cooperative captive-breeding
program initiated in 1985 between the Service, DNER, VIDPNR, and the
Toledo Zoological Garden. Cayo Diablo provided the founding individuals
for the captive population that was reintroduced to Cayo Ratones (6
kilometers (3.5 miles) away from Cayo Diablo), and St. Thomas provided
the founding individuals for the captive population that was
reintroduced to the USVI Cay (4 kilometers (2.5 miles) away from St.
Thomas).
The Cayo Ratones population originated from 41 captive-born boas
(offspring of Cayo Diablo boas) released between 1993 and 1995. Post-
release survival was high: 82.6 percent of individuals and 89 percent
of neonates survived at least 1 year (Tolson 1996a, unpaginated). By
2004, the population had grown to an estimated 500 boas (Tolson et al.
2008, p. 68). Unfortunately, since 2004, Cayo Ratones has been
recolonized by rats, and no boas were found during surveys in 2018
(Island Conservation 2018, pp. 5, 20). However, because Virgin Islands
boas are difficult to find, and this survey was not exhaustive, we
believe it is premature to conclude the population has been extirpated.
Intensive follow-up surveys are needed to confirm whether a population
still persists or is extirpated, but it is clear that the population
has declined.
The USVI Cay reintroduction was initiated with the release of 42
Virgin Islands boas in 2002 and 2003, 11 from captivity and 31 from St.
Thomas. Follow-up surveys in 2003-2004 provided an estimate of 168 boas
(202 boas/ha), which researchers suspected was near carrying capacity
for the island (Tolson 2005, p. 9). More recent surveys in 2018
detected 20 boas over 2 nights, resulting in an estimate of 26-33 boas
across the island (Island Conservation 2018, pp. 20-30). Differences in
survey and analysis methodologies complicate direct comparisons of
population size between these time points. Recent surveys also indicate
that there are no rats on the island.
Factors for consideration for future reintroduction sites include
the presence and amount of suitable habitat (e.g., appropriate forest
structure, adequate prey base, available refugia), protection status or
threat of development, the presence/absence/eradication of exotic
predators, and geomorphology that provides protection from SLR and
hurricane storm surges that are likely to affect the persistence of
low-lying habitat. Potential sites for new introductions have been
suggested (Reynolds et al. 2015, p. 499) and need to be further
assessed, although one new effort is in the early stages of
implementation. Some areas may require that predators be removed before
boas are moved and future monitoring is ensured to prevent
recolonization. In addition to reintroductions to new sites,
augmentation of existing populations may prove beneficial or necessary
for the persistence of existing populations, particularly on developed
islands and cays where predators have become reestablished.
In conclusion, the Virgin Islands boa still faces the threat of
development on St. Thomas, R[iacute]o Grande, and Culebra Island, and
regulatory mechanisms addressing this threat are difficult to enforce
or do not cover all development actions affecting the species. Human
development results in habitat loss from deforestation and
fragmentation, mortality from vehicular strikes, and increased
predation by cats and rats. In addition, impacts from changes in
climate could affect habitat. Drought could negatively influence Virgin
Islands boa populations through loss of prey. SLR and storm surges are
expected to inundate low-lying islands, such as Cayo Diablo, Cayo
Ratones, and the USVI Cay, which currently support Virgin Islands boa
populations. Finally, persecution of boas by citizens, due to fear or
superstition, can affect individual boas, although there has never been
a systematic study of the impact of these events on the overall
population.
When considering conservation actions and how they influence the
viability of Virgin Islands boa, about half of known localities where
Virgin Islands boas occur are on small offshore islets managed for
conservation. In addition, predator removal has been successful at
smaller cays, such as USVI Cay, although the reestablishment of rats on
Cayo Ratones illustrates the need for continued monitoring and removal
efforts. Lastly, successful reintroductions of Virgin Islands boas
occurred on these islands after the eradication of predators; however,
additional predator removal and augmentation of reintroduced boa
populations may be needed on cays where predators have become
reestablished.
Summary of Current Condition
For the Virgin Islands boa to maintain viability, its populations,
or some portion thereof, must be resilient. For the SSA, our
classification of resiliency relied heavily on habitat characteristics
in the absence of highly certain population size or trend estimates.
The habitat characteristics we assessed were: Degree of habitat
protection (or, conversely, development risk), presence of introduced
predators, and vulnerability to storm surges (Service 2018, p. 31).
Representation can be measured by the breadth of genetic or
environmental diversity within and among populations and gauges the
probability that a species is capable of adapting to environmental
changes. A range-wide genetic analysis of the Virgin Islands boa showed
there was little genetic variation; however, the same study found that
each sampled locality had unique mtDNA haplotypes, indicating a lack of
gene flow between islands (Rodr[iacute]guez-Robles et al. 2015,
entire). Therefore, in the SSA we used genetics to delineate
representative units.
The species also needs to exhibit some degree of redundancy in
order to maintain viability. Catastrophic events that could affect both
single and multiple populations of the Virgin Islands boa include
drought, hurricanes, and colonization or recolonization of exotic
predators. This species occurs in geographically isolated groups and
does not disperse from island to island to interact and interbreed;
therefore, for purposes of analyzing redundancy, all boas within each
island were considered to be individual populations.
Resiliency
Because resiliency is a population-level attribute, the key to
assessing it is the ability to delineate populations. As discussed
above, we considered all boas within each island to be single
populations. On small offshore cays, what we define as a population
might consist of a single interbreeding deme (or subdivision) of Virgin
Islands boas. On larger islands, what we define as a population
functions more as a metapopulation, with multiple interbreeding groups
in isolated habitat patches that may interact weakly via dispersal and
recolonization of extirpated patches. Alternately, multiple occupied
patches on large islands may be completely isolated from one another
(Service 2018, p. 20).
[[Page 61707]]
Six island populations were considered: Cayo Diablo, Cayo Ratones,
Culebra Island, R[iacute]o Grande (Puerto Rico), St. Thomas, and USVI
Cay (USVI). We acknowledge the uncertainty about the persistence of
Virgin Islands boas on Cayo Ratones due to the recolonization of the
island by rats; however, because of reasons described previously, we
included this island in our analysis. Further, one or more populations
exist in the BVI, but data are severely limited, and for the SSA, we
lacked sufficient data from these islands to incorporate them into our
viability analysis. In addition, other populations may occur on islands
in Puerto Rico and USVI, but Virgin Islands boa habitat and activity
patterns make them difficult to find, and we could not confirm any to
be extant at the time we completed our analysis.
Resiliency scores for each population were generated by combining
scores for three habitat metrics (Protection/Development Risk, Exotic
Mammals, and Storm Surge Risk) and one population metric (Population
Size and/or Trend, dependent on availability). Each metric was weighted
equally, with the overall effect that habitat (three metrics) was
weighted three times higher than population size/trend (one metric).
For each metric, populations were assigned a score of -1, 0, or 1, as
described below in table 1.
The scores were based on the best available information for each
population, gathered from the literature and species experts.
Monitoring data are scarce. The Virgin Islands boa recovery plan
(Service 1986, pp. 16-19) called for periodic monitoring to estimate
population sizes and trends, but surveys since then have been few and
far between. Survey methodology and reporting have varied from
population to population, with survey results given as estimated
abundances, estimated densities, or encounter rates per person-hour of
searching. The above-described factors in combination contribute to
high levels of uncertainty in current and past population sizes, and
how they have changed over time. Accordingly, resiliency
classifications relied more heavily on habitat conditions than
population size and trend estimates.
Table 1--Description of Habitat and Population Factor Scores To Determine Virgin Islands Boa Population
Resiliency
----------------------------------------------------------------------------------------------------------------
Habitat metrics Population metric
---------------------------------------------------------------------------------------
Score Habitat protection/ Population size/
development risk Exotic mammals Storm surge risk trend *
----------------------------------------------------------------------------------------------------------------
-1...................... Habitat not Exotic mammals Topography and Relatively low
protected, at risk present. elevation leaves population size and/
of being developed. population or declining trend.
vulnerable to storm
surges.
0....................... Some habitat NA.................. NA.................. Relatively moderate
protected, some at population size and
risk of being stable trend, OR
developed. High degree of
uncertainty in
population size/
trends.
1....................... Habitat protected in Exotic mammals Protected by Relatively high
identified absent. topography and population size and/
protected area. elevation. or growth.
----------------------------------------------------------------------------------------------------------------
* Population size/trend scores are relative and were based on the best available information for each
population, gathered from the literature and species experts.
The scores for each population across all metrics were summed, and
final population resiliency categories were assigned as follows:
Low Resiliency: -4 to -2
Moderately Low Resiliency: -1
Moderate Resiliency: 0
Moderately High Resiliency: 1
High Resiliency: 2 to 4
Applying these resiliency categories to the six populations of
Virgin Islands boa, we determined that one population has moderately
high resiliency (Cayo Diablo), one has moderate resiliency (USVI Cay),
one has moderately low resiliency (Culebra), and three have low
resiliency (Cayo Ratones, R[iacute]o Grande, and St. Thomas).
The population classified as having moderately high resiliency
(Cayo Diablo) occurs on a small offshore island that is free of exotic
rats and cats and is protected for conservation. In addition, Cayo
Diablo was surveyed in 2018 with 10 boas being found (Island
Conservation 2018). Extrapolating the density within the transect area
(2.9 boas/ha) to the entire island, the model provides an estimate of
20 boas on the island (95% confidence interval 13-39), which is much
lower than earlier unpublished survey results, however comparisons
cannot be made between the surveys because of different survey and
analytical methodologies (Service 2018, p.23). Primarily because of the
protected and exotic-mammal-free state of the habitat, this population
is considered to have moderately high resiliency to demographic and
environmental stochastic events and disturbances (e.g., fluctuations in
demographic rates, variation in climatic conditions, illegal human
activities).
The USVI Cay population, also on a protected offshore island with
no exotic mammals, was determined to have moderate resiliency. Recent
surveys have revealed a potential decline in abundance and the loss of
two prey species (Smith 2018a, pp. 7-8), possibly as a result of
density dependence as the population approached carrying capacity after
reintroduction. Over two separate survey efforts in 2018, researchers
found a total of 64 boas (Smith 2018ab, entire).
Three of the populations (R[iacute]o Grande, Culebra, and St.
Thomas) with low or moderately low resiliency occur on larger and
higher elevation islands, which provide more protection from storm
surges, but have more human-boa interactions, habitat loss and
fragmentation from development, and exotic cats and rats. Recent
surveys in 2018 on R[iacute]o Grande found three boas (three survey
nights) (Island Conservation 2018, p. 20). For Culebra, surveys in 2018
found no boas (Island Conservation 2018, p. 20); however, two
individuals were documented in February 2019 within the Culebra
National Wildlife Refuge (Puente-Rol[oacute]n and Vega-Castillo 2019,
p. 18). On October 2019, another individual was confirmed in an area
outside of the Refuge (Rom[aacute]n 2019, pers. comm.). For St. Thomas,
there have been no recent systematic surveys for the species as much of
eastern St. Thomas is
[[Page 61708]]
inaccessible due to private ownership or impenetrable habitat; however,
opportunistic observations have averaged about 10 observations of
Virgin Islands boa per year since 2000. The remaining low-resiliency
population (Cayo Ratones) is classified as such as a result of the
recolonization of rats on the island and resulting declining trend--or
possible extirpation--of boas, as no boas were detected during recent
survey efforts (Island Conservation 2018).
Representation
A range-wide genetic analysis of Virgin Islands boa showed that
there was little genetic variation within the species
(Rodr[iacute]guez-Robles et al. 2015, p. 150), supporting the idea that
there is only one representative unit of Virgin Islands boa. However,
each sampled island, and each sampled locality within the same island,
had unique mtDNA haplotypes, indicating a lack of gene flow between
islands/populations (Rodr[iacute]guez-Robles et al. 2015, p. 150).
These results suggest that each population has a different genetic
signature, perhaps as a result of genetic adaptations to their local
environment, or genetic drift with increasing isolation of small
populations. The reintroduction program took this view, and managed
captive populations sourced from Cayo Diablo and St. Thomas separately
(Tolson 1996b, p. 412). To minimize the chances of introducing
individuals poorly suited to their new environment, the captive
population sourced from Cayo Diablo founded the reintroduced population
on nearby Cayo Ratones, and the captive St. Thomas population founded
the reintroduced population on the nearby USVI Cay (Tolson 1996b, p.
412).
In addition to genetic differences, the six populations also have
noticeable phenotypic differences. These are not just limited to
coloration differences between USVI and Puerto Rican populations
(Tolson 1996b, p. 412); Cayo Diablo reportedly has lighter coloration
than the R[iacute]o Grande and Culebra populations (Tolson 2018, pers.
comm.). The R[iacute]o Grande population also occurs in a different
habitat type (subtropical moist forest) than the others (subtropical
dry or littoral forest; Tolson 1996b, p. 410).
In light of this information, we considered each of the four
natural populations in Puerto Rico and USVI as a representative unit
(table 2). The Cayo Diablo population is considered to have moderately
high resiliency. As this was the source for the low-resiliency Cayo
Ratones population, there are two populations representing the Cayo
Diablo genetic signature. Similarly, the USVI Cay population was
sourced from St. Thomas, so there are two populations with St. Thomas
representation, with neither considered to have high resiliency. The
other two natural populations, Culebra and R[iacute]o Grande, both
characterized as having moderately low or low resiliency, have not been
used for captive breeding and reintroduction, so have no additional
populations on other islands with the same genetic characteristics.
Overall, three of four representative units have at least one moderate
resilient population.
While currently we could consider the USVI Cay and Cayo Ratones
reintroduced populations (currently with moderate and low resiliency,
respectively) to be redundant populations sharing the same genetic
signature and adaptive potential as their source populations, all of
the islands occupied by Virgin Islands boa are isolated from each
other. Without human-mediated movement of boas between islands, the
reintroduced populations are expected to diverge genetically from their
source populations over time, and may at some point in the future
(decades to centuries; Reynolds et al. 2015, entire) be different
enough to be considered its own unique representative unit.
Table 2--Representation: Number of Virgin Islands Boa Populations of Each Resiliency Class in Each
Representative Unit, Corresponding to Natural (Not Introduced) Populations, Which Themselves Correspond to
Unique Genetic Signatures
----------------------------------------------------------------------------------------------------------------
Moderately
high Moderate Moderately low Low resiliency
Natural population (genetic signature) resiliency resiliency resiliency populations
populations populations populations
----------------------------------------------------------------------------------------------------------------
Cayo Diablo..................................... 1 0 0 1
Culebra......................................... 0 0 1 0
R[iacute]o Grande............................... 0 0 0 1
St. Thomas...................................... 0 1 0 1
----------------------------------------------------------------------------------------------------------------
Redundancy
Redundancy describes the ability of a species to withstand
catastrophic events. Measured by the number of populations, their
resiliency (ability of a species to withstand environmental and
demographic stochasticity (e.g., wet or dry years)) and their
distribution (and connectivity), redundancy gauges the probability that
the species has a margin of safety to withstand or return from
catastrophic events (such as a rare destructive natural event or
episode involving many populations).
The exact historical distribution of the Virgin Islands boa is
unknown, but their present disjointed distribution suggests that they
were once more widely distributed across small islands within their
range, which have been subject to local extirpations from habitat
degradation, invasive species, and historical climate and sea level
changes. However, for current redundancy, we identified the six
populations in Puerto Rico and USVI (and one or more populations in the
BVI of unknown status). As discussed above, three of these populations
are considered to have resiliency; therefore, the species is moderately
buffered against the effects of catastrophic events.
Summary
Of the six assessed populations, the Cayo Diablo population is the
only one that currently has moderately high resiliency, the USVI Cay
population has moderate resiliency, and the Culebra population has
moderately low resiliency. The other three assessed populations
currently have low resiliency. Redundancy for the species includes
populations on six islands in Puerto Rico and USVI, and possibly more
in the BVI, although not part of this assessment. Representation
consists of four representative units, two of which have two
populations representing its genetic signature, and three of the four
units have populations with some level of resiliency.
The Virgin Islands boa has demonstrated some ability to adapt to
changing environmental conditions over time from both anthropogenic
threats (e.g., habitat disturbance due to
[[Page 61709]]
development) and natural disturbances (e.g., predation and hurricanes).
Compared to historical distribution at the time of listing that
included three locations (Puerto Rico, St. Thomas, and Tortola), the
species currently has six populations (potentially more if the species
persists in the BVI and others are eventually confirmed). Three of the
six current populations exhibit varying levels of resiliency from
moderately high to moderately low, whereas three exhibit low
resiliency. Since the species was listed as an endangered species in
1970, it has demonstrated some degree of resiliency despite threats.
Future Conditions
To assess the future resiliency, redundancy, and representation for
the Virgin Islands boa, we considered impacts of human development,
habitat protection and restoration, reintroductions, public outreach
and education, and SLR. We predicted resiliency at two future time
points, 30 years and ~80 years in the future (2048 and 2100).
Predictions made at the 80-year time point are based only on SLR and
hurricane storm surges as predictions about the other factors are too
uncertain to allow for a meaningful analysis. As discussed in
Determination of Status below, all of the impacts were considered at
the 30-year time step. With input from species' experts, we chose the
30-year time step in order to encompass multiple generations of Virgin
Islands boa (which can live past 20 years and reproduce at 2-3 years of
age; Tolson 1989, p. 166; Tolson and Pi[ntilde]ero 1985, unpaginated).
In addition, we considered the time required to plan and execute a
reintroduction (about 10 years; Tolson 2018, pers. comm.) and how a 30-
year time step would allow us to see results of reintroduction efforts.
Lastly, we considered the time required for habitat restoration to be
realized (10 years or less; Platenberg 2018, pers. comm). The 30-year
time step coincides with the foreseeable future for this analysis
(i.e., the period of time in which we can make reliable predictions).
For information on predictions made at the 80-year time step, see the
SSA report (Service 2018, pp. 38-46).
We did not explicitly consider the role that genetics may play in
the future. Although the absence of natural migration of boas between
islands isolates these populations and makes them vulnerable to
inbreeding and genetic drift, no genetic abnormalities or evidence of
inbreeding depression have been observed in the boa (Tolson 1996b, p.
412). We also did not explicitly consider the impacts of climate change
(other than SLR and hurricane storm surges) on the boas and their
habitat. Species that are dependent on specialized habitat types and
limited in distribution and migration ability, such as the Virgin
Islands boa, are susceptible to the impacts of climate change (Byers
and Norris 2011, p. 22), but the direction, magnitude, and timeframe of
these impacts on the species are uncertain.
Below we present three plausible future scenarios for the Virgin
Islands boa over the next 30 years (to 2048): Status Quo, Conservation,
and Pessimistic. Impacts of climate change and SLR are treated the same
across all three scenarios, as the trajectory of climate change will
proceed regardless of different levels of local conservation for Virgin
Islands boa. For all three scenarios, SLR is considered to occur at a
rate of 0.30 meters (1 foot) by 2048, and 0.61-0.91 meters (2-3 feet)
by 2100 (Church et al. 2013; Service 2018, pp. 38-41). Multiple major
hurricanes are expected to strike within the Virgin Islands boa's
range.
Under a status quo scenario: Development continues at the current
pace, and development and exotic mammals continue to negatively impact
Virgin Islands boa populations. Boa population sizes in these developed
areas decline, as they are suspected to currently be in decline by
species experts (but hard data are lacking to confirm trends). No new
habitat is protected. Under this scenario, one new reintroduction that
has already been initiated with the 2018 capture of snakes to
reinvigorate captive breeding takes place.
Under a conservation scenario: While development continues on
human-occupied islands, under this scenario new Virgin Islands boa
habitat is protected from development on the Puerto Rico main island,
and additional habitat is protected on Culebra and St. Thomas (where
some habitat is already protected), to preserve and restore habitat and
habitat connectivity. Because of the size of the islands and human
populations there, exotic cats and rats remain problematic, but this
risk would be reduced by conservation efforts including predator
control and effective community outreach and education about the effect
of free-roaming cats on native wildlife. Regulations and enforcement
improve on protected lands. Rats are eradicated (and eradication
efforts are monitored) from Cayo Ratones and, if necessary, more boas
are translocated there. Reintroductions occur at a rate of one site per
decade, including the one reintroduction already planned, and
struggling populations on developed islands are augmented.
Under a pessimistic scenario: Under the Pessimistic scenario, no
reintroductions occur, presumably due to reduced funds or changes in
governmental or conservation priorities. No additional habitat is
protected, and development continues to impact populations on human-
inhabited islands. Exotic mammals remain a threat where already
present. Rats colonize Cayo Diablo and recolonize the USVI Cay.
Given current resources, priorities, and conservation momentum, the
Status Quo scenario is the most likely scenario for the future. The
Status Quo scenario includes the implementation of a new
reintroduction, which is planned but contingent on continued funding
(not yet secured) and a long-term commitment to manage and propagate a
captive population, select a suitable site (which may involve rat
eradication), reintroduce boas, and conduct post-release monitoring.
The likelihoods of the Conservation and Pessimistic scenarios are
contingent upon the decisions, resources, and priorities of management
and conservation organizations, which are difficult to predict. The
Pessimistic scenario is likely if funds and effort are not directed to
captive breeding and reintroduction, community outreach and education,
habitat protection and restoration, and ongoing monitoring of Virgin
Islands boas, their habitat, and exotic species. The Conservation
scenario is likely if abundant funds and effort are directed towards
these initiatives.
Resiliency
Under all three future scenarios, the three populations on
developed islands are predicted to remain at low resiliency or become
extirpated by 2048 (table 3). Even with conservation efforts to prevent
extirpation, none of the populations are expected to improve their
resiliency because of the magnitude of the threats facing them. Cayo
Diablo, the population with the highest resiliency, is expected to
continue to have high resiliency unless the island is colonized by
rats, which could drive the population to extirpation. Cayo Ratones,
which presently has a robust rat population, will remain at low
resiliency and potential extirpation unless rats are eradicated;
supplemental translocations may also be necessary, but more surveys are
necessary to determine the needs of the population. Given that the
threats facing populations on developed islands will be very difficult
to surmount, the most effective way to increase the
[[Page 61710]]
overall resiliency of populations range-wide is to reintroduce new
populations in quality protected habitat, prevent future colonization
by exotic predators, and have continual predator eradication
monitoring.
Table 3--Summary Table of Future Resiliency for Virgin Islands Boa Populations in 2048 Under Three Scenarios
----------------------------------------------------------------------------------------------------------------
Current Future--status Future--conservation Future--pessimistic
Population resiliency quo (2048) (2048) (2048)
----------------------------------------------------------------------------------------------------------------
Cayo Diablo................... Moderately High.. Moderately High. High................. Low/Extirpated.
Cayo Ratones.................. Low.............. Low/Extirpated.. High................. Low/Extirpated.
Culebra....................... Moderately Low... Low/Extirpated.. Moderately Low....... Low/Extirpated.
R[iacute]o Grande............. Low.............. Low/Extirpated.. Low.................. Low/Extirpated.
St. Thomas.................... Low.............. Low/Extirpated.. Low.................. Low/Extirpated.
USVI Cay...................... Moderate......... Moderate........ High................. Low/Extirpated.
New (introduced) populations None............. 1 High.......... 3 High............... None.
(pops).
Summary (# pops).............. 6 pops........... 3-7 pops........ 9 pops............... 0-6 pops.
Low: 3........... Low/Extirpated: Low: 2............... Low/Extirpated: 6.
Mod Low: 1....... 4. Mod Low:1............ High: 0.
Moderate: 1...... Moderate: 1..... High: 6..............
Mod High: 1...... Mod High:1......
High: 1.........
----------------------------------------------------------------------------------------------------------------
Redundancy
The total number of populations under the Status Quo scenario is
three to seven depending on whether four populations become extirpated
or remain at a low resiliency. Under the Pessimistic scenario, all
populations are predicted to be extirpated or remain at low resiliency.
The Conservation scenario improves redundancy by introducing three new
populations that are expected to have high resiliency, improving the
resiliency of the Cayo Ratones population by eradicating rats and
providing translocations if needed, and preventing low-resiliency
populations from becoming extirpated, for a total of nine populations.
As time goes on after the horizon of our 30-year scenarios, SLR becomes
more important to consider, as current populations with the highest
resiliency potential are the same populations that will be most at risk
from SLR.
Representation
In the Current Condition section above, we identified each natural
(not introduced) Virgin Islands boa population as a representative
unit. Under this concept, a reintroduced population is of the same
representative unit as the source population used for the
reintroduction, and future representation for the species depends
highly on how reintroductions are carried out (table 11 in Service
2018, p. 59).
The Status Quo scenario includes one reintroduction sourced from
the USVI Cay population, which was originally sourced from the St.
Thomas population. Therefore, the new reintroduced population would be
considered part of the St. Thomas representative unit. The Conservation
scenario includes two additional reintroductions, which could be
sourced from any population. Sourcing new reintroductions from Culebra
or R[iacute]o Grande would improve redundancy within representative
units, but other factors such as geographic proximity to the
reintroduction site and availability of source boas also factor into
the decision of where to source reintroductions. The Pessimistic
scenario does not include any new reintroduced populations.
Summary
Conservation of existing populations of Virgin Islands boas and
their habitat on developed islands, via population augmentation and
habitat restoration (in occupied areas and to establish migration
corridors), is important to contribute to resiliency and redundancy
within representative areas for the species. The future condition of
the Virgin Islands boa was assessed under three scenarios 30 years into
the future. Under the Status Quo scenario, development continues to
impact the populations on developed islands, no new habitat is
protected, and one new reintroduction takes place. Two moderately high
or high-resiliency populations are predicted to remain after 30 years
(Cayo Diablo and a new reintroduced population), while USVI Cay remains
in moderate resiliency, and the remaining four populations are
predicted to have low resiliency or potentially be extirpated.
Under the Conservation scenario, some habitat on the three
developed islands is protected for conservation/restoration,
reintroductions occur at a rate of one per decade, and presence of
exotic mammals are monitored and controlled (though likely not
eradicated) via continuous eradication efforts and public outreach. Six
high-resiliency populations are predicted to exist after 30 years.
Under this scenario, three populations are expected to have moderately
low or low resiliency, but are protected from complete extirpation by
active conservation measures. Under the Pessimistic scenario,
development continues to impact populations on developed islands, no
reintroductions occur, and rats colonize/recolonize the islands where
they are not currently present. No highly resilient populations are
predicted to remain after 30 years, and all six current populations are
at risk of extirpation.
Redundancy increases under the Status Quo and Conservation
scenarios; however, under the Pessimistic scenario, no high-resiliency
populations remain. Representation remains the same four units under
the Status Quo scenario. Under the Conservation scenario, redundancy
may improve within representative units with the addition of two more
reintroduced populations, depending on where those populations are
sourced. Based on our analysis, we consider the Status Quo scenario to
be the most likely scenario, and therefore expect the Virgin Islands
boa will have three resilient populations at our 30-year timeframe,
with continued redundancy and representation.
We also assessed the risk from SLR and hurricanes at 30 years into
the future. In 30 years, SLR alone is unlikely to significantly impact
Virgin Islands boa populations, with approximately 4-5 percent of land
predicted to be inundated (Service 2018, p. 43). Habitat on low-lying
cays (Cayo Diablo, Cayo Ratones, and USVI Cay) has proven to be
resilient to hurricanes
[[Page 61711]]
in the past, and likely will remain so with 0.30 meters (1 foot) of SLR
expected over the next 30 years, although the exact impacts of any
particular future storm are impossible to predict. Overall, USVI Cay is
most at risk from SLR and storm impacts, while there is a moderate risk
of SLR impacts to Virgin Islands boas and habitat on Cayo Diablo and
Cayo Ratones, and low risk at Culebra, R[iacute]o Grande, and St.
Thomas.
We note that, by using the SSA framework to guide our analysis of
the scientific information documented in the SSA report, we have not
only analyzed individual effects on the species, but we have also
analyzed their potential cumulative effects. We incorporate the
cumulative effects into our SSA analysis when we characterize the
current and future condition of the species. Our assessment of the
current and future conditions encompasses and incorporates the threats
individually and cumulatively. Our current and future condition
assessment is iterative because it accumulates and evaluates the
effects of all the 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.
Recovery and Recovery Plan Implementation
Section 4(f) of the Act directs us to develop and implement
recovery plans for the conservation and survival of endangered and
threatened species unless we determine that such a plan will not
promote the conservation of the species. Recovery plans are not
regulatory documents and are instead intended to establish goals for
long-term conservation of a listed species; define criteria that are
designed to indicate when the threats facing a species have been
removed or reduced to such an extent that the species may no longer
need the protections of the Act; and provide guidance to our Federal,
State, and other governmental and nongovernmental partners on methods
to minimize threats to listed species.
There are many paths to accomplishing recovery of a species, and
recovery may be achieved without all of the criteria in a recovery plan
being fully met. For example, one or more criteria may be exceeded
while other criteria may not yet be accomplished. In that instance, we
may determine that the threats are minimized sufficiently and the
species is robust enough to delist. In other cases, recovery
opportunities may be discovered that were not known when the recovery
plan was finalized. These opportunities may be used instead of methods
identified in the recovery plan. Likewise, information on the species
may be learned that was not known at the time the recovery plan was
finalized. The new information may change the extent to which existing
criteria are appropriate for recognizing recovery of the species.
Recovery of a species is a dynamic process requiring adaptive
management that may, or may not, follow all of the guidance provided in
a recovery plan.
The Virgin Islands Tree Boa Recovery Plan, issued by the Service on
March 27, 1986, did not contain measurable criteria. An amendment to
the recovery plan was issued in September 2019 to include quantitative
delisting criteria. The amended recovery plan suggests that recovery be
defined in the following terms:
Delisting Criterion 1. Existing two (2) Virgin Islands boa
populations with the highest resiliency (Cayo Diablo and USVI Cay)
exhibit a stable or increasing trend, evidenced by natural recruitment
and multiple age classes. This criterion has been partially met.
Ensuring the conservation of resilient populations is important for the
recovery of the Virgin Islands boa as it will help those populations to
further withstand catastrophic and stochastic events. The populations
of the Virgin Islands boa at Cayo Diablo and USVI Cay are considered
potentially declining (Tolson 2004, p. 11; Tolson et al. 2008, p. 68),
and currently have moderately high and moderate resiliency,
respectively (Service 2018, pp. 23, 28). Both Cayo Diablo and USVI cay
are free of exotic predators/competitors and are protected as part of
natural reserves. Habitat conditions are recovering following
hurricanes, and Virgin Islands boas continue to persist, with upwards
of 20 boas estimated on Cayo Diablo, and boas appear to be at carrying
capacity on USVI Cay (Service 2018, pp. 23, 28). In addition, these
resilient populations may serve as sources to establish the new
populations outlined in Criterion 2, if maintained at their current
level. Virgin Islands boas have already been collected from the USVI
Cay population to establish a captive-breeding program in order to
implement Criterion 2.
Five islands (Culebra, R[iacute]o Grande (Puerto Rico), St. Thomas,
Cayo Ratones, and Tortola) currently have Virgin Islands boas present,
although population numbers and age class structures are unknown. Cayo
Ratones had a thriving population, with 41 introduced boas in 1993-1995
having high survival and wild reproduction and were able to increase
numbers to nearly 500 boas by 2005 (Tolson et al. 2008, p. 68; Service
2018, p. 24). However, recent surveys in 2018 did not detect any boas,
but did uncover a robust rat population (Island Conservation 2018,
entire; Service 2018, p. 24). Because Virgin Islands boas are hard to
find and habitat conditions remain in good condition post hurricanes,
there is not enough evidence to indicate boa extirpation, although the
reestablishment of rats is likely causing decline in this population.
For Culebra, surveys in 2018 found no boas (Island Conservation 2018,
p. 20); however, two individuals were documented in February 2019
within the Culebra National Wildlife Refuge (Puente-Rol[oacute]n and
Vega-Castillo 2019, p. 18). On October 2019, another individual was
confirmed in an area outside of the Refuge (Rom[aacute]n 2019, pers.
comm.). The Puerto Rican R[iacute]o Grande population has consistent
but very low encounter rates for Virgin Islands boas, with three
observed during recent 2018 surveys. These two populations were
determined to have low (R[iacute]o Grande) and moderately low (Culebra)
resiliency. Similarly, the species has been sighted on St. Thomas
(Platenberg and Harvey 2010, entire), and earlier estimates assessed
the population to be about 400 individuals (Tolson 1991, p. 11).
Despite lack of recent surveys on St. Thomas (primarily due to
inaccessibility of habitat), opportunistic reports indicate
approximately 10 Virgin Islands boa observations per year since 2000
(Service 2018, p. 27). The SSA classifies this population as having low
resiliency. Virgin Islands boas are known to occur on Tortola (and
likely several other British Virgin islands); however, no data are
available about the size or status of those populations (Service 2018,
p. 29).
Delisting Criterion 2. Establish three (3) additional
populations that show a stable or increasing trend, evidenced by
natural recruitment and multiple age classes. This criterion has not
been met. Increasing the number of resilient populations will improve
the species' viability. In order to expand the species' distribution,
these new populations will be established on protected suitable habitat
where threats from invasive mammals are not present and SLR will have
minimal impact on the habitat. In addition, increasing the number of
populations and broadening the species' distribution will enhance their
ability to
[[Page 61712]]
withstand catastrophic and stochastic events. For this species, it is
believed that three additional populations exhibiting these traits is
necessary to ensure sufficient redundancy such that the species will no
longer require protection under the Act.
Delisting Criterion 3. Threats are reduced or eliminated
to the degree that the species is viable for the foreseeable future.
This criterion has been partially met. The primary threats to Virgin
Islands boa are development, predation/competition from exotic mammals,
climate change, and persecution from the public. Virgin Islands boa
populations have coexisted with urban development on Culebra,
R[iacute]o Grande, St. Thomas, and several British Virgin islands,
although impacts from the development appear to cause a decline in
these populations. Consequences of human development on the boa and its
habitat include habitat loss and fragmentation due to deforestation,
mortality from vehicular strikes, and an increase in predators/
competitors, such as cats and rats. Three islands (Cayo Diablo, Cayo
Ratones, and USVI Cay) are protected from development impacts. The
threat of predation/competition by exotic mammals can be reduced/
eliminated, but requires continual monitoring and eradication efforts.
In 1985, a successful rat control program was started, and Cayo Ratones
and USVI Cay were identified as potentially suitable for the
reintroduction of the species. At one time, rats had been eliminated on
Cayo Ratones, but they have since returned and are in robust numbers.
Rats on USVI Cay have been eliminated, and Virgin Islands boas are
established there. In areas where urban development is prevalent, it is
unlikely that feral cats and rats will be fully eradicated. Storm surge
and SLR are the effects of climate change that are projected to impact
Virgin Islands boa populations; however, the species has thus far
proven to be resilient to severe storms (and associated storm surge)
and SLR is not expected to significantly impact the species in the
foreseeable future (see Future Conditions, above). Finally, intentional
killing of Virgin Islands boas, whether due to fear of snakes or
confusion with other snakes, has been identified as a threat; however,
the extent of the effect of persecution on Virgin Islands boa
populations is unknown.
Summary
The amended Virgin Islands boa recovery plan (Service 2019)
contains three recovery criteria for delisting the species: Two Virgin
Islands boa populations exhibit a stable or increasing trend, evidenced
by natural recruitment and multiple age classes; three additional
populations show a stable or increasing trend, evidenced by natural
recruitment and multiple age classes; and threats are reduced or
eliminated to the degree that the species is viable for the foreseeable
future. Based on the information gathered and analyzed, two of these
criteria have been partially met.
Determination of Virgin Islands Boa Status
Section 4 of the Act (16 U.S.C. 1533), and its implementing
regulations at 50 CFR part 424, set forth the procedures for
determining whether a species meets the definition of endangered
species or 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 ``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
``endangered species'' or ``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.
Status Throughout All of Its Range
After evaluating threats to the species and assessing the
cumulative effects of the threats under the section 4(a)(1) factors, we
find that, while the present or threatened destruction, modification,
or curtailment of its habitat (Factor A) remains a threat for at least
three of the populations, three of the six populations fully occur in
protected areas, and we expect the species' population resiliency to
ameliorate the threat in the future. The Virgin Islands boa's habitat
is found on both private and publicly owned lands. Past, current and
expanding urban development will continue to impact the Virgin Islands
boa on the main islands (i.e., St. Thomas, R[iacute]o Grande (Puerto
Rico), and Culebra), which are under development pressure related to
urban expansion and tourism; however, not all areas of the species'
range occur near population centers. Half of the currently known
populations are found on islands and small islets that are managed for
conservation by the territorial governments of Puerto Rico and USVI,
and the Culebra Island population occurs both within private and
protected areas (i.e., Culebra National Wildlife Refuge).
Predation by exotic mammals, namely cats and rats, remains a threat
to the Virgin Islands boa (Factor C). While there is no evidence of
rats preying directly on the Virgin Islands boa, Virgin Islands boas
are generally not present on islands with high densities of rats. This
is likely due to competition for prey rather than predation.
Reintroductions of Virgin Islands boas have been successful on islands
where rat populations have been exterminated. Feral cats are known to
prey on boas and are an ongoing threat to the species.
The fear of snakes, as well as superstitious beliefs and even
confusion with other snakes, may contribute to the intentional killing
of Virgin Islands boas (Factor E), although there has not yet been a
systematic study done to determine if these individual deaths are
having a species-wide effect.
Due to the limited distribution of Virgin Islands boas, climate
change and SLR (Factor E) may also have an impact. Low-lying islands
and parts of larger islands, where Virgin Islands boa populations are
supported, are vulnerable to SLR and storm surge. The species has
persisted despite major hurricane events, although there may be impacts
to habitat (e.g., die-off of vegetation) due to storm surge.
The Virgin Islands boa has demonstrated some ability to adapt to
changing environmental conditions over time (representation) from both
anthropogenic threats (e.g., habitat disturbance due to development)
and natural disturbances (e.g., predation and hurricanes). Since the
species was listed as an endangered species in 1970, it has
demonstrated resiliency despite threats. Since the writing of the
recovery plan (Service 1986, entire), two new populations have been
reintroduced (Cayo Ratones and USVI Cay) and two previously unknown
populations have been discovered (Culebra and R[iacute]o Grande),
although the continued persistence of the Cayo Ratones population is
uncertain. There are currently at least six populations (not including
those potentially on the BVI) with varying levels of resiliency; one
population has moderately high resiliency, one has moderate resiliency,
one has moderately low resiliency, and three have low resiliency. Based
on the biology of the species and the documented responses to the
development and reintroductions since
[[Page 61713]]
listing, we expect the species to respond the same way in the
foreseeable future.
Our implementing regulations at 50 CFR 424.11(d) set forth a
framework within which we evaluate the foreseeable future on a case-by-
case basis. The term foreseeable future extends only so far into the
future as the Services can reasonably determine that both the future
threats and the species' responses to those threats are likely. In
other words, the foreseeable future is the period of time in which we
can make reliable predictions. ``Reliable'' does not mean ``certain'';
it means sufficient to provide a reasonable degree of confidence in the
prediction. Thus, a prediction is reliable if it is reasonable to
depend on it when making decisions.
It is not always possible or necessary to define foreseeable future
as a particular number of years. Analysis of the foreseeable future
uses the best scientific and commercial data available and should
consider the timeframes applicable to the relevant threats and to the
species' likely responses to those threats in view of its life-history
characteristics. Data that are typically relevant to assessing the
species' biological response include species-specific factors such as
lifespan, reproductive rates or productivity, certain behaviors, and
other demographic factors.
The foreseeable future described here uses the best available data
and considers the species' life-history characteristics, threat
projection timeframes, and environmental variability, which may affect
the reliability of projections. We also considered the timeframes
applicable to the relevant threats and to the species' likely responses
to those threats in view of its life-history characteristics. We
determined the foreseeable future to be 30 years from present. As
discussed above, the SSA's future scenarios considered impacts from
development, habitat restoration and protection, reintroductions of the
Virgin Islands boa, and SLR. Based on the modeling and scenarios
evaluated for Virgin Islands boa, we considered our ability to make
reliable predictions in the future and the uncertainty with regard to
how and to what degree the species would respond to factors within this
timeframe. In addition, the timing and response of habitat to
restoration efforts (presumably multiple efforts needed, and spaced out
over time as funding and resources permit) and the species' response to
those improved habitat conditions, as well as the lifespan of the
species (which can exceed 20 years in captivity) also informed our
foreseeable future timeframe.
Taking into account the impacts of the factors based on the Status
Quo scenario, and because the Virgin Islands boa contains three
relatively resilient populations now (i.e., having moderately high to
moderately low resiliency), and two of those populations are predicted
to maintain their moderate to moderately high resiliency in the future,
especially in populations where exotic mammals are not present, we
expect the species to maintain populations on two of the six islands
within the foreseeable future. However, continuation of the current
population trends for these two populations into the future is
dependent on management (e.g., habitat conservation/preservation and
predator control/eradication). Under the Status Quo scenario, the three
populations on developed islands are predicted to possibly become
extirpated by 2048. Under the Conservation Scenario, up to six
populations are predicted to become highly resilient within the
foreseeable future. While threat intensity and management needs vary
somewhat across the range of the species (e.g., urban population areas
versus non-populated conserved areas), Virgin Islands boa populations
on islands throughout the range of the species continue to be reliant
on active conservation management and require adequate implementation
of regulatory mechanisms, and all remain vulnerable to threats that
could cause substantial population declines in the foreseeable future
(e.g., feral cat predation).
Despite the existing regulatory mechanisms and conservation
efforts, the factors identified above continue to affect the Virgin
Islands boa. However, the species has persisted with varying degrees of
resiliency since it was listed in 1970. Once known from three
locations, now known from at least six locations, the species was
successfully introduced to two new locations (one possibly extirpated
by uncontrolled exotic mammals) and discovered at two new locations,
and could be at additional locations in the unsurveyed BVI and other
areas in St. Thomas; thus, the known distribution has expanded since
listing. Thus, after assessing the best available information, we
determine that the Virgin Islands boa is not currently in danger of
extinction, but is likely to become in danger of extinction within the
foreseeable future, throughout all of its range.
Status Throughout a Significant Portion of Its Range
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. The court in Center for Biological Diversity v. Everson,
2020 WL 437289 (D.D.C. Jan. 28, 2020) (Center for Biological
Diversity), vacated the aspect of the 2014 Significant Portion of its
Range Policy that provided that the Services do not undertake an
analysis of significant portions of a species' range if the species
warrants listing as threatened throughout all 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 Center for Biological Diversity,
we now consider whether there are any significant portions of the
species' range where the species is in danger of extinction now (i.e.,
endangered). In undertaking this analysis for Virgin Islands boa, we
choose to address the status question first--we consider information
pertaining to the geographic distribution of both the species and the
threats that the species faces to identify any portions of the range
where the species is endangered.
For Virgin Islands boa, we considered whether the threats are
geographically concentrated in any portion of the species' range at a
biologically meaningful scale. We examined the following threats:
Habitat loss and degradation from development, introduced predators,
SLR and a changing climate, and public attitudes towards snakes,
including cumulative effects. For detailed descriptions of each threat,
see Summary of Biological Status and Threats, above.
Impacts from habitat loss and degradation are prevalent throughout
the range of the Virgin Islands boa. The boas occur on both privately
and publicly owned land. Habitat loss and fragmentation from
deforestation happens with the development of privately owned land, and
even occurs around protected areas. Habitat loss also happens from SLR.
Loss of habitat due to SLR and storm surge impacts is similar to loss
of habitat due to
[[Page 61714]]
development where the loss of low-lying forest habitat could result in
decreased habitat availability for the Virgin Islands boas and their
prey. All known islands and cays that are occupied by Virgin Islands
boas are threatened with habitat loss and fragmentation.
Similarly, the threat of introduced predators is of concern range-
wide for the Virgin Islands boa. Feral cats are known to prey upon
boas, and rats may predate on neonate boas or compete with boas for
prey. Cats and rats are easily introduced to islands, usually via boat.
Efforts to eliminate exotic mammalian predators has been successful on
some of the smaller cays, but requires continual removal and monitoring
on the larger developed islands.
Climate change is expected to influence Virgin Islands boa
persistence throughout its range into the future. Species that are
limited in distribution, such as the Virgin Islands boa, are
susceptible to the impacts of climate change. Temperatures throughout
the Caribbean are expected to rise, precipitation is likely to decrease
(resulting in drought), and tropical storms may occur less frequently
but with more force. Every island and cay within the range of the
Virgin Island boa is susceptible to these impacts from a changing
climate.
The intentional killing of Virgin Islands boas is a threat to the
species regardless of where it occurs. While those boas that live in
proximity to developed areas are more susceptible to intentional
killings, public fear towards snakes is a threat that can impact the
boas throughout their range.
Low population numbers can be considered a threat such that the
other threats acting on the species can result in a concentration of
threats to extremely small populations. Data presented in the SSA
indicate that current population trend estimates for Virgin Island boas
in Puerto Rico and USVI are uncertain, indicating that they are either
declining, potentially declining, considered rare, or unknown, but most
populations are small or considered rare. Rarity does not necessarily
equate to dangerously small population sizes, and because the survey
methodologies and reporting has varied from population to population
and over time, population size and trend estimates were not exclusively
relied on to determine resiliency. Despite the rarity of Virgin Island
boas on most islands, the species has demonstrated resiliency for
decades, and is predicted to continue to maintain resiliency, despite
threats. Therefore small population numbers across the range of the
species are not considered to contribute to a concentration of threats.
We found no concentration of threats in any portion of the Virgin
Islands boa's range at a biologically meaningful scale. Thus, there are
no portions of the species' range where the species has a different
status from its rangewide status. Therefore, no portion of the species'
range provides a basis for determining that the species is in danger of
extinction in a significant portion of its range, and we determine that
the species is likely to become in danger of extinction within the
foreseeable future throughout all of its range. This is consistent with
the courts' holdings in Desert Survivors v. Department of the Interior,
No. 16-cv-01165-JCS, 2018 WL 4053447 (N.D. Cal. Aug. 24, 2018), and
Center for Biological Diversity v. Jewell, 248 F. Supp. 3d, 946, 959
(D. Ariz. 2017).
Determination of Status
Our review of the best available scientific and commercial
information indicates that the Virgin Islands boa meets the definition
of a threatened species. Therefore, we propose to reclassify the Virgin
Islands boa as a threatened species in accordance with sections 3(20)
and 4(a)(1) of the Act.
II. Proposed Rule Issued Under Section 4(d) of the Act
Background
Section 4(d) of the Act contains two sentences. The first sentence
states that the ``Secretary shall issue such regulations as he deems
necessary and advisable to provide for the conservation'' of species
listed as threatened. The U.S. Supreme Court has noted that statutory
language like ``necessary and advisable'' demonstrates a large degree
of deference to the agency (see Webster v. Doe, 486 U.S. 592 (1988)).
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.'' Thus, the combination of the
two sentences of section 4(d) provides the Secretary with wide latitude
of discretion to select and promulgate appropriate regulations tailored
to the specific conservation needs of the threatened species. The
second sentence grants particularly broad discretion to the Service
when adopting the prohibitions under section 9.
The courts have recognized the extent of the Secretary's discretion
under this standard to develop rules that are appropriate for the
conservation of a species. For example, courts have upheld rules
developed under section 4(d) as a valid exercise of agency authority
where they prohibited take of threatened wildlife, or include a limited
taking prohibition (see Alsea Valley Alliance v. Lautenbacher, 2007
U.S. Dist. Lexis 60203 (D. Or. 2007); Washington Environmental Council
v. National Marine Fisheries Service, 2002 U.S. Dist. Lexis 5432 (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 him with regard to the permitted activities for those species. He
may, for example, permit taking, but not importation of such species,
or he 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).
Exercising our authority under section 4(d), we have developed a
species-specific proposed rule that is designed to address the Virgin
Islands boa's specific threats and conservation needs. Although the
statute does not require the Service to make a ``necessary and
advisable'' finding with respect to the adoption of specific
prohibitions under section 9, we find that this rule taken as a whole
satisfies the requirement in section 4(d) of the Act to issue
regulations deemed necessary and advisable to provide for the
conservation of the Virgin Islands boa. As discussed above under
Summary of Biological Status and Threats, the Service has concluded
that the Virgin Islands boa is likely to become in danger of extinction
within the foreseeable future primarily due to development-associated
impacts (i.e., habitat fragmentation and loss, vehicular strikes),
predation/competition by exotic species, climate change, and
persecution by the public. In addition, the species is management
reliant in that it depends on maintaining current levels of management
and establishing new populations into suitable habitat. Therefore, the
provisions of this proposed 4(d) rule would promote
[[Page 61715]]
conservation of the Virgin Islands boa by encouraging species
restoration efforts. The provisions of this proposed rule are one of
many tools that the Service would use to promote the conservation of
the Virgin Islands boa. The proposed 4(d) rule would apply only if and
when the Service makes final the reclassification of the Virgin Islands
boa as a threatened species.
Provisions of the Proposed 4(d) Rule
The proposed 4(d) rule would provide for the conservation of the
Virgin Islands boa by prohibiting the following activities, except as
otherwise authorized or permitted: Import or export; take; possession
and other acts with unlawfully taken specimens; delivery, receipt,
transport, or shipment in interstate or foreign commerce in the course
of commercial activity; or sale or offering for sale in interstate or
foreign commerce. We also propose several exceptions to these
prohibitions, which along with the prohibitions are set forth under
Proposed Regulation Promulgation, below.
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
regulation at 50 CFR 17.3. Take can result knowingly or otherwise, by
direct and indirect impacts, intentionally or incidentally. Regulating
incidental and intentional take would help preserve the species'
remaining populations, enable beneficial management actions to occur,
and decrease synergistic, negative effects from other stressors.
Protecting the Virgin Islands boa from direct and indirect forms of
take, such as physical injury or killing, whether incidental or
intentional, will help preserve and recover the remaining populations
of the species. Therefore, we propose to prohibit intentional and
incidental take of Virgin Islands boa, including, but not limited to,
capturing, handling, trapping, collecting, destruction and modification
of its habitat, or any other activities that would result in take of
the species.
As discussed above under Summary of Biological Status and Threats,
a range of activities have the potential to impact the species,
including development, intentional killing of boas by private citizens,
and introduction of exotic predators/competitors (e.g., cats, rats).
Regulating these activities will help preserve the remaining
populations and protect individual boas.
Protecting the Virgin Islands boa from incidental take, such as
harm that results from habitat degradation, will likewise help preserve
the species' populations and also decrease negative effects from other
stressors impeding recovery of the species. The species' continuance
may be dependent upon active management occurring on the islands and
cays, especially as it concerns exotic predator control and human
development. Most offshore islands and cays where the Virgin Islands
boa is found are protected by municipal, territorial, and Federal
agencies. However, existing land protections provided by those agencies
are not comprehensive for the Virgin Islands boa and are often not
enforced.
We determined that one of the primary threats to the Virgin Islands
boa is the presence of exotic mammals, which, when present in high
densities, is indicative of a lack of boa populations. Therefore, any
introduction of exotic species, such as cats or rats, that compete
with, prey upon, or destroy the habitat of the Virgin Islands boa would
further impact the species and its habitat and therefore will also be
prohibited by the proposed 4(d) rule.
Maintaining and expanding existing populations, and creating new
populations, is also vital to the conservation of the Virgin Islands
boa. Therefore, the proposed 4(d) rule would provide for the
conservation of the species by excepting from the take prohibitions
conservation efforts by Federal, Commonwealth, Territory, and municipal
wildlife agencies to benefit the Virgin Islands boa, including control
and eradication of exotic mammals, habitat restoration, and collection
of broodstock, tissue collection for genetic analysis, captive
propagation, and reintroduction into currently occupied and unoccupied
areas within the historical range of the species. Efforts by these
wildlife agency entities to monitor and survey Virgin Islands boa
populations and habitat that require handling, temporary holding, pit
tagging, tissue sampling, and release would also be excepted from the
take prohibitions under this proposed 4(d) rule.
The fear of snakes, as well as superstitious beliefs, may
contribute to the intentional killing of boas. Although we cannot
address fear or beliefs in a 4(d) rule, we can except from the
prohibitions take associated with removing boas from houses and other
structures to provide alternatives to killing individual boas.
Therefore, the proposed 4(d) rule would except from the prohibitions
take associated with nonlethal removal of Virgin Islands boas from
human structures, and returning them to natural habitat.
Even for activities prohibited by the 4(d) rule, including those
described above, we may issue permits to carry out those activities
involving threatened wildlife under certain circumstances. Regulations
governing permits are codified at 50 CFR 17.32. With regard to
threatened wildlife, a permit may be 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. There are also certain statutory exemptions from
the prohibitions, which are found in sections 9 and 10 of the Act.
The Service recognizes the special and unique relationship with our
State, Commonwealth, and Territory natural resource agency partners in
contributing to conservation of listed species. State, Commonwealth,
and Territory agencies often possess scientific data and valuable
expertise on the status and distribution of endangered, threatened, and
candidate species of wildlife and plants. These agencies, because of
their authorities and their close working relationships with local
governments and landowners, are in a unique position to assist the
Service in implementing all aspects of the Act. In this regard, section
6 of the Act provides that the Service shall cooperate to the maximum
extent practicable with the States, Commonwealths, and Territories in
carrying out programs authorized by the Act. Therefore, any qualified
employee or agent of a Commonwealth or Territory conservation agency
that is a party to a cooperative agreement with the Service in
accordance with section 6(c) of the Act, who is designated by his or
her agency for such purposes, would be able to conduct activities
designed to conserve the Virgin Islands boa that may result in
otherwise prohibited take without additional authorization.
Nothing in this proposed 4(d) rule would change 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 of
the Service to enter into partnerships for the management and
protection of the Virgin Islands boa. However, interagency cooperation
may be further streamlined through planned programmatic consultations
for the species between Federal agencies and the Service. We ask the
public, particularly Commonwealth and Territorial agencies and other
interested stakeholders that may be affected by the proposed 4(d) rule,
to provide comments and suggestions regarding
[[Page 61716]]
additional guidance and methods that the Service could provide or use,
respectively, to streamline the implementation of this proposed 4(d)
rule (see Information Requested, above).
Effects of This Proposed Rule
This proposal, if made final, would revise 50 CFR 17.11 to
reclassify the Virgin Islands boa from endangered to threatened on the
List of Endangered and Threatened Wildlife. Additionally, if the
proposed 4(d) rule is adopted in a final rule, the Service will detail
prohibitions set forth at 50 CFR 17.21 and 17.32, except for incidental
take associated with conservation efforts by Federal, Commonwealth,
Territory, or municipal wildlife agencies; nonlethal removal from human
structures; and monitoring and survey efforts of Virgin Islands boa. In
addition, we will revise the List of Endangered and Threatened Wildlife
to change the species' scientific name to Chilabothrus granti.
Required Determinations
Clarity of the Proposed Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(a) Be logically organized;
(b) Use the active voice to address readers directly;
(c) Use clear language rather than jargon;
(d) Be divided into short sections and sentences; and
(e) 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.
National Environmental Policy Act (42 U.S.C. 4321 et seq.)
It is our position that, outside the jurisdiction of the U.S. Court
of Appeals for the Tenth Circuit, we do not need to prepare
environmental analyses pursuant to the National Environmental Policy
Act (NEPA; 42 U.S.C. 4321 et seq.) in connection with designating
critical habitat under the Act. We published a notice outlining our
reasons for this determination in the Federal Register on October 25,
1983 (48 FR 49244). This position was upheld by the U.S. Court of
Appeals for the Ninth Circuit (Douglas County v. Babbitt, 48 F.3d 1495
(9th Cir. 1995), cert. denied 516 U.S. 1042 (1996)).
Government-to-Government Relationship With Tribes
In accordance with the President's memorandum of April 29, 1994,
``Government-to-Government Relations with Native American Tribal
Governments'' (59 FR 22951), Executive Order 13175, and the Department
of the Interior's manual at 512 DM 2, we readily acknowledge our
responsibility to communicate meaningfully with recognized Federal
Tribes on a government-to-government basis. In accordance with
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights,
Federal-Tribal Trust Responsibilities, and the Endangered Species Act),
we readily acknowledge our responsibilities to work directly with
tribes in developing programs for healthy ecosystems, to acknowledge
that tribal lands are not subject to the same controls as Federal
public lands, to remain sensitive to Indian culture, and to make
information available to tribes. There are no tribal lands associated
with this proposed rule.
References Cited
A complete list of references cited is available on the internet at
https://www.regulations.gov under Docket No. FWS-R4-ES-2019-0069 and
upon request from the Field Supervisor, Caribbean Ecological Services
Field Office (see FOR FURTHER INFORMATION CONTACT, above).
Authors
The primary authors of this proposed rule are staff members of the
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, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; and 4201-4245,
unless otherwise noted.
Sec. 17.11 Endangered and threatened wildlife.
0
2. Amend Sec. 17.11 in paragraph (h) by revising the entry for ``Boa,
Virgin Islands tree'' under REPTILES in the List of Endangered and
Threatened Wildlife to read as follows:
----------------------------------------------------------------------------------------------------------------
Listing citations and
Common name Scientific name Where listed Status applicable rules
----------------------------------------------------------------------------------------------------------------
* * * * * * *
Reptiles
* * * * * * *
Boa, Virgin Islands tree........ Chilabothrus granti Wherever found.... T 35 FR 16047, 10/13/
1970; 44 FR 70677, 12/
7/1979; [Federal
Register citation of
the final rule]. 50
CFR 17.42(j).\4d\
* * * * * * *
----------------------------------------------------------------------------------------------------------------
0
3. Amend Sec. 17.42 by adding paragraph (j) to read as set forth
below:
Sec. 17.42 Special rules--reptiles.
* * * * *
(j) Virgin Islands tree boa (Chilabothrus granti)--(1)
Prohibitions. The following prohibitions that apply to endangered
wildlife also apply to Virgin Islands tree boa. Except as provided
under paragraph (j)(2) of this section and Sec. Sec. 17.4 and 17.5, it
is unlawful for any person subject to the jurisdiction of
[[Page 61717]]
the United States to commit, to attempt to commit, to solicit another
to commit, or cause to be committed, any of the following activities in
regard to this species:
(i) Import or export, as set forth at Sec. 17.21(b);
(ii) Take, as set forth at Sec. 17.21(c)(1);
(iii) Possession and other acts with unlawfully taken specimens, as
set forth at Sec. 17.21(d)(1);
(iv) Interstate or foreign commerce in the course of commercial
activity, as set forth at Sec. 17.21(e); and
(v) Sale or offer for sale, as set forth at Sec. 17.21(f).
(vi) The intentional or incidental introduction of exotic species,
such as cats or rats, that compete with, prey upon, or destroy the
habitat of the Virgin Islands boa is also prohibited.
(2) Exceptions from prohibitions. In regard to this species, you
may:
(i) Conduct activities as authorized by a permit under Sec. 17.32.
(ii) Take, as set forth at Sec. 17.21(c)(2) through (c)(4) for
endangered wildlife.
(iii) Take, as set forth at Sec. 17.31(b).
(iv) Possess and engage in other acts with unlawfully taken
endangered wildlife, as set forth at Sec. 17.21(d)(2).
(v) Incidental take of Virgin Islands tree boa resulting from:
(A) Conservation efforts by Federal, Commonwealth, Territory, or
municipal wildlife agencies, including, but not limited to, control and
eradication of exotic mammals and habitat restoration, and collection
of broodstock, tissue collection for genetic analysis, captive
propagation, and reintroduction into currently occupied or unoccupied
areas within the historical range of the Virgin Islands tree boa.
(B) Nonlethal removal (and return to natural habitat) of Virgin
Islands tree boa from human structures, defense of human life, and
authorized capture and handling of Virgin Islands tree boas.
(C) Efforts to monitor and survey Virgin Islands tree boa
populations and habitat that may include handling, temporary holding,
pit tagging, tissue sampling, and release.
Aurelia Skipwith,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2020-19027 Filed 9-29-20; 8:45 am]
BILLING CODE 4333-15-P
