[Federal Register Volume 78, Number 158 (Thursday, August 15, 2013)]
[Proposed Rules]
[Pages 49878-49901]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-19794]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2013-0084;
RIN 1018-AZ08
Endangered and Threatened Wildlife and Plants; Endangered Status
for the Florida Leafwing and Bartram's Scrub-Hairstreak Butterflies
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (USFWS), propose to
list the Florida leafwing (Anaea troglodyta floridalis) and Bartram's
scrub-hairstreak (Strymon acis bartrami) butterflies as endangered
species under the Endangered Species Act. If we finalize this rule as
proposed, it would extend the Act's protections to these species. The
effect of these regulations is to conserve the Florida leafwing and
Bartram's scrub-hairstreak under the Act.
DATES: We will accept comments received or postmarked on or before
October 15, 2013. Comments submitted electronically using the Federal
eRulemaking Portal (see ADDRESSES section, below) must be received by
11:59 p.m. Eastern Time on the closing date. We must receive requests
for public hearings, in writing, at the address shown in FOR FURTHER
INFORMATION CONTACT by September 30, 2013.
ADDRESSES: You may submit comments by one of the following methods:
[[Page 49879]]
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the search box, enter FWS-R4-ES-2013-0084,
which is the docket number for this rulemaking. You may submit a
comment by clicking on ``Comment Now''.
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R4-ES-2013-0084; Division of Policy and
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax
Drive, MS 2042-PDM; Arlington, VA 22203.
We request that you send comments only by the methods described
above. We will post all information received on http://www.regulations.gov. This generally means that we will post any
personal information you provide us (see the Public Comments section
below for more information).
FOR FURTHER INFORMATION CONTACT: Larry Williams, Field Supervisor, U.S.
Fish and Wildlife Service, South Florida Ecological Services Office,
1339 20th Street, Vero Beach, FL 32960, by telephone 772-562-3909, or
by facsimile 772-562-4288. Persons who use a telecommunications device
for the deaf (TDD) may call the Federal Information Relay Service
(FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, if a species is
determined to be an endangered or threatened species throughout all or
a significant portion of its range, we are required to promptly publish
a proposal in the Federal Register and make a determination on our
proposal within 1 year. Critical habitat shall be designated, to the
maximum extent prudent and determinable, for any species determined to
be an endangered or threatened species under the Act. Listing a species
as an endangered or threatened species and designations of critical
habitat can be completed only by issuing a rule. Elsewhere in today's
Federal Register, we propose to designate critical habitat for the
Florida leafwing butterfly and Bartram's scrub hairstreak butterfly
under the Act.
This rule consists of: A proposed rule to list the Florida leafwing
butterfly (Anaea troglodyta floridalis) and the Bartram's scrub-
hairstreak butterfly (Strymon acis bartrami) as endangered species.
Both butterflies are candidate species for which we have on file
sufficient information on biological vulnerability and threats to
support preparation of a listing proposal, but for which development of
a listing regulation has until now been precluded by other higher
priority listing activities. This rule reassesses all available
information regarding status of and threats to both butterfly
subspecies.
The basis for our action. Under the Act, we can determine that a
species is an endangered or threatened species based on 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 the threats to both subspecies fall under all
five factors, and consist of a lack of adequate fire management, small
population size, isolation from habitat loss and fragmentation, loss of
genetic diversity, inadequate regulatory mechanisms, pesticide
applications, poaching, hurricanes and storm surge, and sea level rise.
We will seek peer review. We are seeking comments from
knowledgeable individuals with scientific expertise to review our
analysis of the best available science and application of that science
and to provide any additional scientific information to improve this
proposed rule. Because we will consider all comments and information
received during the comment period, our final determinations may differ
from this proposal.
Information Requested
We intend that any final action resulting from this proposed rule
will be based on the best scientific and commercial data available and
be as accurate and as effective as possible. Therefore, we request
comments or information from the public, other concerned governmental
agencies, Native American tribes, the scientific community, industry,
or any other interested parties concerning this proposed rule. We
particularly seek comments concerning:
(1) Both species' biology, range, and population trends, including:
(a) Habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for the species, their
habitat, or both.
(2) The factors that are the basis for making a listing
determination for a species under section 4(a) of the Act, which are:
(a) The present or threatened destruction, modification, or
curtailment of their 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 their continued
existence.
(3) Biological, commercial trade, or other relevant data concerning
any threats (or lack thereof) to these species and regulations that may
be addressing those threats; including the use and effects of
pesticides to control mosquitos and other insects considered pests.
(4) The use of prescribed fire or other management tools to
simulate historical natural disturbances to restore or maintain the
species habitat.
(5) Additional information concerning the historical and current
status, range, distribution, and population size of these species,
including the locations of any additional populations of these species.
(6) Current or planned activities in the areas occupied by these
species and possible impacts of these activities on these species.
Please note that submissions merely stating support for or
opposition to the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is an endangered or threatened
species must be made ``solely on the basis of the best scientific and
commercial data available.''
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in ADDRESSES. We request that you
send comments only by the methods described in ADDRESSES.
If you submit information via http://www.regulations.gov, your
entire submission--including any personal identifying information--will
be posted on the Web site. If your submission is made via a hardcopy
that includes personal identifying information, you may request at the
top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so. We
will post all hardcopy submissions on http://www.regulations.gov.
Please include sufficient information with your
[[Page 49880]]
comments to allow us to verify any scientific or commercial information
you include.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection on http://www.regulations.gov, or by
appointment, during normal business hours, at the U.S. Fish and
Wildlife Service, South Florida Ecological Services Office (see FOR
FURTHER INFORMATION CONTACT).
Previous Federal Actions
The Florida leafwing and Bartram's scrub-hairstreak (previously
known as the Bartram's hairstreak) butterflies have the same history of
being candidates for listing under the Act. Both butterflies were first
recognized as candidates on May 22, 1984 (49 FR 21664). We assigned
both species a listing priority number (LPN) of 2. Candidate species
are assigned LPNs based on immediacy and magnitude of threats, as well
as taxonomic status. The lower the LPN, the higher priority that
species is for us to determine appropriate action using our available
resources (September 21, 1983; 48 FR 43100). Category 2 species were
defined as species for which we had information that proposed listing
was possibly appropriate, but conclusive data on biological
vulnerability and threats were not available to support a proposed rule
at the time. Both species remained on the candidate list, as published
in what is now known as the Candidate Notice of Review (CNOR), as
category 2 species until 1994 (January 6, 1989, 54 FR 572; November 21,
1991, 56 FR 58830). Both species were removed from the candidate list
from 1996 to 2005 because we did not have sufficient information on the
species' biological vulnerability and threats to support issuance of a
proposed rule. Both species were added to the candidate list in the
2006 CNOR and assigned an LPN of 3 (September 12, 2006, 71 FR 53760).
An LPN of 3 meant that the magnitude of threats remained high and
immediate with recognition of their taxonomic status as subspecies.
Both species remained on the candidate list as published in the CNORs
from 2007 to 2012 with the LPN of 3 (72 FR 69034, December 6, 2007; 73
FR 75176, December 10, 2008; 74 FR 578040, November 9, 2009; 75 FR
69222, November 10, 2010; 76 FR 66370, October 26, 2011; and November
21, 2012, 77 FR 69994).
On May 10, 2011, the Service announced a work plan to restore
biological priorities and certainty to the Service's listing process.
As part of an agreement with one of the agency's most frequent
plaintiffs, the Service filed a work plan with the U.S. District Court
for the District of Columbia. The work plan will enable the agency to,
over a period of 6 years, systematically review and address the needs
of more than 250 species listed within the 2010 Candidate Notice of
Review, including the Florida leafwing and Bartram's scrub-hairstreak,
to determine if these species should be added to the Federal Lists of
Endangered and Threatened Wildlife and Plants. This work plan will
enable the Service to again prioritize its workload based on the needs
of candidate species, while also providing State wildlife agencies,
stakeholders, and other partners clarity and certainty about when
listing determinations will be made. On July 12, 2011, the Service
reached an agreement with a frequent plaintiff group and further
strengthened the workplan, which will allow the agency to focus its
resources on the species most in need of protection under the Act.
These agreements were approved on September 9, 2011. The timing of this
proposed listing is, in part, therefore, an outcome of the workplan.
The Service's decision to propose listing of the Florida leafwing
and Bartram's scrub-hairstreak resulted from our careful review of the
status of these butterflies and assessments of their threats.
Elsewhere in today's Federal Register, we propose to designate
critical habitat for the Florida leafwing and Bartram's scrub-
hairstreak butterflies under the Act.
Status Assessment for the Florida Leafwing and Bartram's Scrub-
Hairstreak Butterflies
Florida Leafwing
General Biology
The Florida leafwing butterfly is a medium-sized butterfly
approximately 76 to 78 millimeters (mm) (2.75 to 3.00 inches (in)) in
length with a forewing length of 34 to 38 mm (1.3 to 1.5 in) and an
appearance characteristic of its genus (Comstock 1961, p. 44; Pyle
1981, p. 651; Opler and Krizek 1984, p. 172; Minno and Emmel 1993, p.
153). The upper-wing (or open wing) surface color is red to red-brown.
The underside (closed wings) is gray to tan, with a tapered outline,
cryptically looking like a dead leaf or the bark of slash pine trees
(Pinus elliottii var. densa) when the butterfly is at rest. The Florida
leafwing exhibits sexual dimorphism (male and female are different from
each other), with females being slightly larger and with darker
coloring along the wing margins than the males. The butterfly also has
seasonal forms (Comstock 1961, pp. 44-45; Salvato and Hennessey 2003,
p. 244). Comstock (1961, pp. 44-45) employed the terms ``summer'' and
``winter'' morph to differentiate between seasonal forms within the
genus. The length of photoperiod exposure experienced by fifth-instar
larvae (larvae several days prior to pupation), as well as the
influence of seasonal moisture, have been identified as key factors in
determining the seasonal forms within members of the Anaea genus of
leafwing butterflies (Riley 1980, p. 333; 1988a, p. 266; 1988b, p. 226;
Salvato and Hennessey 2003, p. 246). The summer form (wet-season or
long-day form), occurring in late May to September, tends to have
forewing margins that are blunt and hind-wings with a less pronounced
tail; colors also tend to be brighter. The winter form (dry-season or
short-day form), occurring in October to early May, tends to have the
opposing characters, with pronounced tails and crescent-shaped
forewings (Comstock 1961, pp. 44-45; Salvato 1999, p. 118; Salvato and
Hennessey 2003, p. 246).
The Florida leafwing has only one known hostplant, the pineland
croton (Croton linearis) (Euphorbiaceae). The immature stages of this
butterfly feed on pineland croton for development. As in the adult
butterfly stage, the larval development of the leafwing also displays a
cryptic mimicry of the host plant. The first three instars
(developmental life stages) of a five instar larval development begin
what continues throughout larval development to be a cryptic mimicry of
the hostplant. These stages appear like dead leaves, with a brown color
and resting on a dead part of the plant during the day (Salvato 1999,
p. 118; 2003, p. 244). Early instars tend to eat the leaves to the mid-
vein and then dangle from them in camouflage. They dangle by creating a
frass chain (strings composed of silk and feces) for protection from
predators (Salvato and Salvato 2008, p. 327). Briefly, a frass chain is
created when the larvae attach their fecal pellets to the mid-vein of a
partially eaten croton leaf with silk (Minno et al. 2005, p. 115). The
larvae crawl to the terminus of the strands to avoid predation. The two
later instars are light green in color, with a tapering body from the
cephalad (head capsule) to the caudal end (posterior), so that, when at
rest, it also appears like a croton leaf in the spiral fashion of the
terminal end of the leaf (Worth et al. 1996, p. 64). The head capsule
during all stages bears many tiny setae (bristles), presenting the
granular
[[Page 49881]]
appearance of croton seeds (Worth et al. 1996, p. 64).
Taxonomy
The Florida leafwing butterfly (Anaea troglodyta floridalis) was
first described by Johnson and Comstock in 1941. Anaea troglodyta
floridalis is a taxon considered to be both endemic to south Florida
and clearly derived from Antillean stock (the islands of the West
Indies except for the Bahamas, separating the Caribbean Sea from the
Atlantic Ocean) (Comstock 1961, p. 45; Brown and Heineman 1972, p. 124;
Minno and Emmel 1993, p. 153; Smith et al. 1994, p. 67; Salvato 1999,
p. 117; Hernandez 2004, p. 39; Pelham 2008, p. 393). Some authors
(Comstock 1961, p. 44; Miller and Brown 1981, p. 164; Smith et al.
1994, p. 67; Hernandez 2004, p. 39) placed the Florida leafwing as a
distinct species, A. floridalis. Others (Brown and Heineman 1972, p.
124; Minno and Emmel 1993, p. 153; Salvato 1999, p. 117; Opler and
Warren 2003, p. 40) considered the Florida leafwing as a subspecies of
Anaea troglodyta Fabricius. Smith et al. (1994, p. 67) suggested that
further comparison between immature stages of the Florida leafwing and
its Antillean relatives may aid in determining whether or not the
Florida leafwing is distinct at the species or subspecies level. Opler
and Warren (2003, p. 40) and Pelham (2008, p. 393) considered Anaea
troglodyta floridalis, not A. floridalis, as the scientific name for
the Florida leafwing.
The Integrated Taxonomic Information System (ITIS) (2013, p. 1)
uses the name Anaea troglodyta floridalis (F. Johnson and W. Comstock,
1941) and indicates that this subspecies' taxonomic standing is valid.
The Florida Natural Areas Inventory (FNAI) (2012, p. 19) uses the name
A. t. floridalis.
Life History
Numerous authors have observed and documented the behavior and
natural history of the Florida leafwing (Lenczewski 1980, p. 17; Pyle
1981, p. 651; Baggett 1982, pp. 78-79; Opler and Krizek 1984, p. 172;
Schwartz 1987, p. 22; Hennessey and Habeck 1991, pp. 13-17; Smith et
al. 1994, p. 67; Worth et al. 1996, pp. 4-6; Salvato 1999, pp. 116-122;
Salvato and Hennessey 2003, pp. 243-249; Salvato and Salvato 2008, pp.
323-329; 2010a, pp. 91-97). Adults are rapid, wary fliers and have
strong flight abilities and are able to disperse over large areas. The
butterfly is extremely territorial, with both sexes flying out to
pursue other leafwings, as well as other butterfly species (Baggett
1982, p. 78; Worth et al. 1996, p. 65; Salvato and Hennessey 2003, p.
246; Salvato and Salvato 2010a, p. 96). Minno (pers. comm. 2009) and
Salvato and Salvato (2010a, p. 96) noted that males are generally more
territorial. The Florida leafwing is multivoltine (i.e., produces
multiple generations per year), with an entire life cycle of about 2 to
3 months (Hennessey and Habeck 1991, p. 17) and maintains continuous
broods throughout the year (Salvato 1999, p. 121). The precise number
of broods per year remains unknown, but the leafwing has been recorded
in every month (Baggett 1982, p. 78; Opler and Krizek 1984, p. 172;
Minno and Emmel 1993, p. 153; Salvato and Hennessey 2003, p. 247;
Salvato and Salvato 2010a, p. 96; 2010c, p. 140). Salvato and Salvato
(2010a, p. 93) and Land (Everglades National Park (ENP), pers. comm.
2012b) encountered the butterfly throughout the year, but the majority
of observations occurred from late fall to spring in ENP. By contrast,
Salvato and Salvato (2010c, p. 139) reported finding the butterfly on
Big Pine Key, abundantly throughout the year, particularly during the
summer months.
Eggs are spherical and light cream-yellow in color (Worth et al.
1996, p. 64). Females lay eggs singly on both the upper and lower
surface of the host (croton plant) leaves, normally on developing
racemes (flowers) (Baggett 1982, p. 78; Hennessey and Habeck 1991, p.
16; Worth et al. 1996, p. 64; Salvato 1999, p. 120). Worth et al.
(1996, p. 64) and Salvato (1999, p. 120) visually estimated that
females may fly more than 30 meters (m) (98 feet (ft)) in search of a
suitable host plant and usually require less than a minute to oviposit
(lay) each egg.
Adult Florida leafwings will feed on tree sap, take minerals from
mud, and occasionally visit flowers. Adults have also been observed
feeding on rotting fruit and dung (Baggett 1982, p. 78; Opler and
Krizek 1984, p. 172; Minno and Emmel 1993, p. 153), senescent (older)
flowers of saw palmetto (Serenoa repens) (Hennessey and Habeck 1991, p.
13), a sliced orange (Salvato 1999, p. 121), sap of willow bustic
(Sideroxylon salicifolium) excreted from feeding holes created by
yellow-bellied sapsuckers (Sphyrapicus varius) (Salvato and Salvato
2008, p. 326), and sap from slash pines and wild tamarind (Lysiloma
latisiliquum) (Salvato and Salvato 2008, p. 326; Salvato and Salvato
2010a, p. 96). Adults are not frequently attracted to flowers (Baggett
1982, p. 78; Opler and Krizek 1984, p. 172; Worth et al. 1996, p. 65).
However, Salvato and Salvato (2010a, p. 96) observed freshly emerged
adults taking nectar from a variety of plants, including Spanish
needles (Bidens alba), shrub verbena (Lantana camara), and false mallow
(Malvastrum corchorifolium) within a weedy, disturbed area on the
extreme southern border of Long Pine Key in ENP. Lenczewski (1980, p.
17) observed adults at the edges of mud puddles. Salvato and Hennessey
(2003, p. 248) also observed this puddling behavior by adult male
Florida leafwings on Big Pine Key and in ENP.
Bartram's Scrub-Hairstreak
General Biology
The Bartram's scrub-hairstreak is a small butterfly approximately
25 mm (1 in) in length with a forewing length of 10.0 to 12.5 mm (0.4
to 0.5 in) and has an appearance (i.e., dark gray-colored on the upper
(open) wings, light gray-colored under (closed) wings, small size, body
shape, distinctive white barring or dots on underwings, and tailed
hindwings) characteristic of the genus (Pyle 1981, p. 480; Opler and
Krizek 1984, pp. 107-108; Minno and Emmel 1993, p. 129). As with the
Florida leafwing, pineland croton is the only known hostplant for the
Bartram's scrub-hairstreak (Minno and Emmel 1993, p. 129; Smith et al.
1994, p. 118). The Bartram's scrub-hairstreak does not exhibit sexual
or seasonal dimorphism, but does show some sexual differences in
coloration. The abdomen of the male is bright white, while females are
gray (Minno and Emmel 1993, p. 129; Minno and Minno 2009, p. 70).
Eggs are laid singly on the flowering racemes of pineland croton
(Worth et al., 1996, p. 62; Salvato and Hennessey 2004, p. 225). The
immature stages of this butterfly feed on pineland croton for
development. First and second instars remain well camouflaged amongst
the white croton flowers, while the greenish later stages occur more on
the leaves. Salvato and Hennessey (2004, p. 225) reported approximate
body lengths of 2, 4, 6, and 11 mm (0.8, 0.16, 0.24, and 0.43 in) for
Bartram's scrub-hairstreak for the second through fifth instar larvae,
respectively.
Taxonomy
The Bartram's scrub-hairstreak butterfly (Strymon acis bartrami)
was first described by Comstock and Huntington in 1943. Seven
subspecies of Strymon acis have been described (Smith et al. 1994, p.
118). Smith et al. (1994, p. 118) indicated that perhaps no other
butterfly in the West Indies has evolved as many distinct island
subspecies as S. acis. Each group of Antillean islands appears to have
its own particular set of S. acis hairstreaks, and these have been
classified into two
[[Page 49882]]
separate groups. The Type A subspecies are larger, darker colored and
are found in the more southeastern Antillean islands. The Type B
subspecies, to which the Bartram's scrub-hairstreak belongs, are
smaller, more surface-grey colored.
The ITIS (2013, p. 1) uses the name Strymon acis bartrami and
indicates that this subspecies' taxonomic standing is valid. FNAI
(2012, p. 21) uses the name S. a. bartrami.
Life History
The Bartram's scrub-hairstreak is a sedentary butterfly rarely
encountered more than 5 m (16.4 ft) from its host plant (Schwartz 1987,
p. 16; Worth et al. 1996, p. 65; Salvato and Salvato 2008, p. 324).
Females oviposit on the flowering racemes of pineland croton (Worth et
al. 1996, p. 62; Salvato and Hennessey 2004, p. 225). Eggs are laid
singly on the developing flowers. Hennessey and Habeck (1991, p. 18)
observed a female oviposit three eggs over the course of 5 minutes.
This long duration of oviposition likely enables females to serve as
one of the major pollinating species for the host plant (Salvato 2003,
p. 57).
The Bartram's scrub-hairstreak is most often observed visiting
pineland croton flowers for nectar, but has also been observed using
the flowers of other species, including: Pine acacia (Acacia
pinetorum), Spanish needles, saw palmetto (Serenoa repens), button sage
(Lantana involucrata), Bloggett's swallowwort (Cynanchum blodgettii),
Everglades Key false buttonwood (Spermacoce terminalis), locustberry
(Byrsonima lucida), and starrush whitetop (Rhynchospora colorata)
(Minno and Emmel 1993, p. 129; Worth et al. 1996, p. 65; Calhoun et al.
2002, p. 14; Salvato and Hennessey 2004, p. 226; Salvato and Salvato
2008, p. 324; C. Anderson, pers. comm. 2010).
The Bartram's scrub-hairstreak has been observed during every month
on Big Pine Key and ENP; however, the exact number of broods appears to
vary sporadically from year to year (Salvato and Hennessey 2004, p.
226; Salvato and Salvato 2010b, p. 156). Baggett (1982, p. 81)
indicated that the Bartram's scrub-hairstreak seemed most abundant
October-December. Salvato and Salvato (2010b, p. 156) encountered the
butterfly most often during March through June within ENP. Land (pers.
comm. 2012b) has noted the butterfly to be most abundant in the spring
and summer months. One of the earliest reports of S. a. bartrami
phenology from Big Pine Key was provided by Schwartz (1987, p. 16) who
encountered the butterfly only during April, November, and December,
despite an extensive annual survey. Subsequent research by Hennessey
and Habeck (1991, pp. 17-19), Emmel et al. (1995, pp. 14-15), and Minno
and Minno (2009, pp. 70-76) reported occurrences of Bartram's scrub-
hairstreak on Big Pine Key throughout the year with varying peaks in
seasonal abundance. Salvato and Salvato (unpublished data) have
reported finding the butterfly abundant throughout the year on Big Pine
Key, particularly during the late spring. Salvato (1999, p. 47)
suggests the butterfly can occur in high numbers during any season if
suitable habitat and conditions are present. Service Biologist Chad
Anderson (pers. comm. 2012a) has found them most active when the
average temperature is consistently near 27 degrees Celsius ([deg]C)
(80 degrees Fahrenheit ([deg]F)), which can occur at any time of year.
In addition, reference plots and random survey transects on Big Pine
Key have consistently indicated that peak relative abundances can
differ among subpopulations within the same year (Anderson, pers. comm.
2012b).
Florida Leafwing and Bartram's Scrub-Hairstreak
Habitat
The Florida leafwing and Bartram's scrub-hairstreak occur only
within pine rocklands, specifically those that retain their mutual and
sole hostplant, pineland croton. Adult butterflies will also make use
of rockland hammock vegetation when interspersed within the pine
rockland habitat.
Pine Rockland
Pine rockland is characterized by an open canopy of South Florida
slash pine (Pinus elliottii var. densa) with a patchy understory of
tropical and temperate shrubs and palms and a rich herbaceous layer of
mostly perennial species including numerous species endemic to South
Florida. Outcrops of weathered oolitic (small rounded particles or
grains) limestone, known locally as pinnacle rock, are common, and
solution holes may be present. This subtropical, pyrogenic flatland can
be mesic or xeric depending on landscape position and associated
natural communities. There are differences in species composition
between the pine rocklands found in the Florida Keys and the mainland
(FNAI 2010a, p. 1).
Pine rockland has an open canopy of South Florida slash pine,
generally with multiple age classes. The diverse, open shrub and
subcanopy layer is composed of more than 100 species of palms and
hardwoods (FNAI 2010a, p. 1), most derived from the tropical flora of
the West Indies (FNAI 2010a, p. 1). Many of these species vary in
height depending on fire frequency, getting taller with time since
fire. These include saw palmetto (Serenoa repens), cabbage palm (Sabal
palmetto), silver palm (Coccothrinax argentata), brittle thatch palm
(Thrinax morrisii), wax myrtle (Myrica cerifera), myrsine (Rapanea
punctata), poisonwood (Metopium toxiferum), locustberry (Byrsonima
lucida), varnishleaf (Dodonaea viscosa), tetrazygia (Tetrazygia
bicolor), rough velvetseed (Guettarda scabra), marlberry (Ardisia
escallonioides), mangrove berry (Psidium longipes), willow bustic
(Sideroxylon salicifolium), winged sumac (Rhus copallinum). Short-
statured shrubs include running oak (Quercus elliottii), white
indigoberry (Randia aculeata), Christmas berry (Crossopetalum
ilicifolium), redgal (Morinda royoc), and snowberry (Chiococca alba).
Grasses, forbs, and ferns make up a diverse herbaceous layer
ranging from mostly continuous in areas with more soil development and
little exposed rock to sparse where more extensive outcroppings of rock
occur. Typical herbaceous species include bluestems (Andropogon spp.,
Schizachyrium gracile, S. rhizomatum, and S. sanguineum), arrowleaf
threeawn (Aristida purpurascens), lopsided indiangrass (Sorghastrum
secundum), hairawn muhly (Muhlenbergia capillaris), Florida white-top
sedge (Rhynchospora floridensis), pineland noseburn (Tragia saxicola),
devil's potato (Echites umbellata), pineland croton, several species of
sandmats (Chamaesyce spp.), partridge pea (Chamaecrista fasciculata),
coontie (Zamia pumila), maidenhair pineland fern (Anemia adiantifolia),
Bahama brake (Pteris bahamensis), and lacy bracken (Pteridium aquilinum
var. caudatum) (FNAI 2010a, p. 1).
Pine rockland occurs on relatively flat, moderately to well drained
terrain from 2 to 7 m (6.5 to 23 ft) above sea level (FNAI 2010a, p.
2). The oolitic limestone is at or very near the surface, and there is
very little soil development. Soils are generally composed of small
accumulations of nutrient-poor sand, marl, clayey loam, and organic
debris in depressions and crevices in the rock surface. Organic acids
occasionally dissolve the surface limestone causing collapsed
depressions in the surface rock called solution holes (FNAI 2010a, p.
1). Drainage varies according to the porosity of the limestone
substrate, but is generally rapid. Consequently, most sites are wet for
only short periods following heavy rains. During the rainy season,
however, some sites may be
[[Page 49883]]
shallowly inundated by slow-flowing surface water for up to 60 days
each year (FNAI 2010a, p. 1).
Pine rockland is maintained by regular fire, and susceptible to
other natural disturbances such as hurricanes, frost events, and sea-
level rise (Ross et al. 1994). Fires historically burned on an interval
of approximately every 3 to 7 years (FNAI 2010a, p. 3) and were
typically started by lightning strikes during the frequent summer
thunderstorms (FNAI 2010a, p. 3).
Presently, prescribed fire must be periodically introduced into
pine rocklands to sustain community structure, prevent invasion by
woody species, maintain high herbaceous diversity (Loope and Dunevitz
1981, pp. 5-6; FNAI 2010a, p. 3), and prevent succession to rockland
hammock. The amount of woody understory growth is directly related to
the length of time since the last fire. Herbaceous diversity declines
with time since last fire. The ecotone between pine rockland and
rockland hammock is abrupt when regular fire is present in the system.
However when fire is removed, the ecotone becomes more gradual and
subtle as hammock hardwoods encroach into the pineland (FNAI 2010a, p.
3).
Rockland hammock
Rockland hammock is a species-rich tropical hardwood forest on
upland sites in areas where limestone is very near the surface and
often exposed. The forest floor is largely covered by leaf litter with
varying amounts of exposed limestone and has few herbaceous species.
Rockland hammocks typically have larger, more mature trees in the
interior, while the margins can be almost impenetrable in places with
dense growth of smaller shrubs, trees, and vines. Typical canopy and
subcanopy species include, Bursera simaruba, Lysiloma latisiliquum
(false tamarind), Coccoloba diversifolia (pigeon plum), Sideroxylon
foetidissimum (false mastic), Ficus aurea (strangler fig), Piscidia
piscipula (Jamaican dogwood), Ocotea coriacea (lancewood), Drypetes
diversifolia, Simarouba glauca (paradisetree), Sideroxylon salicifolium
(willow bustic), Krugiodendron ferreum (black ironwood), Exothea
paniculata (inkwood), Metopium toxiferum, and Swietenia mahagoni (West
Indies mahogany).
Mature hammocks can be open beneath a tall well-defined canopy and
subcanopy. More commonly, in less mature or disturbed hammocks, dense
woody vegetation of varying heights from canopy to short shrubs is
often present. Species that generally make up the shrub layers within
rockland hammock include several species of Eugenia (stoppers), Thrinax
morrisii and T. radiata (thatch palms), Amyris elemifera (sea
torchwood), Ardisia escallonioides (marlberry), Psychotria nervosa
(wild coffee), Chrysophyllum oliviforme (satinleaf), Sabal palmetto,
Guaiacum sanctum (lignum-vitae), Ximenia americana (hog plum),
Colubrina elliptica (soldierwood), Pithecellobium unguis-cati and
Pithecellobium keyense, Coccoloba uvifera, and Colubrina arborescens
(greenheart). Vines can be common and include Toxicodendron radicans
(eastern poison ivy), Smilax auriculata (earleaf greenbrier), Smilax
havanensis (Everglades greenbrier), Parthenocissus quinquefolia
(Virginia creeper), Hippocratea volubilis (medicine vine), and Morinda
royoc (redgal). The typically sparse short shrub layer may include
Zamia pumila (coontie), and Acanthocereus tetragonus (dildoe cactus).
Herbaceous species are occasionally present and generally sparse in
coverage. Characteristic species include Lasiacis divaricata
(smallcane), Oplismenus hirtellus (woodsgrass) and many species of
ferns (FNAI 2010b, p. 1).
Rockland hammock occurs on a thin layer of highly organic soil
covering limestone on high ground that does not regularly flood, but it
is often dependent upon a high water table to keep humidity levels
high. Rockland hammocks are frequently located near wetlands; in the
Everglades they can occur on organic matter that accumulates on top of
the underlying limestone; in the Florida Keys they occur inland from
tidal flats (FNAI 2010b, p. 1).
Rockland hammock is susceptible to fire, frost, canopy disruption,
and ground water reduction. Rockland hammock can be the advanced
successional stage of pine rockland, especially in cases where rockland
hammock is adjacent to pine rockland. In such cases, when fire is
excluded from pine rockland for 15 to 25 years it can succeed to
rockland hammock vegetation. Historically, rockland hammocks in South
Florida evolved with fire in the landscape, fire most often
extinguished near the edges when it encountered the hammock's moist
microclimate and litter layer. However, rockland hammocks are
susceptible to damage from fire during extreme drought or when the
water table is lowered. In these cases fire can cause tree mortality
and consume the organic soil layer (FNAI 2010b, p. 2).
The lifecycle of both butterflies occur in the pine rocklands, and
in some instances associated rockland hammock vegetation interspersed
within this habitat. Adult leafwings prefer the transitional zones
between pineland and hammock and will disperse and roost within the
pine rockland canopy and associated rockland hammock vegetation (Minno,
pers. comm. 2009; Salvato and Salvato 2008, p. 246; 2010a, p. 96). The
leafwing, with its strong flight abilities, can disperse to make use of
available habitat throughout pine rockland and associated rockland
hammock habitat in ENP. Leafwing dispersed similarly into these
habitats on Big Pine Key until it was extirpated. The hairstreak
prefers more open pine rocklands and is more sedentary than the
leafwing with adults rarely encountered more than 5 m (16 ft) from the
hostplant.
Historical Ranges
The Florida leafwing and Bartram's scrub-hairstreak are endemic to
south Florida including the lower Florida Keys. The butterflies were
locally common within pine rockland habitat that once occurred within
Miami-Dade and Monroe Counties and were less common and sporadic within
croton-bearing pinelands in Collier, Martin (leafwing only), Palm
Beach, and Broward Counties (Comstock and Huntington 1943, p. 65;
Kimball 1965, pp. 45-46; Baggett 1982, p. 78; Smith et al. 1994, p. 67;
Salvato 1999, p. 117; Salvato and Hennessey 2003, p. 243; 2004, p.
223).
There is little evidence that these butterflies ventured further
north than southern Miami-Dade County to make use of localized, relict
populations of hostplants that still persist as far north as Martin
County (Salvato 1999, p. 117; Salvato and Hennessey 2003, p. 243; 2004,
p. 223). Although these butterflies were widely reported from several
locations in southern Miami until the mid-20th century (Smith et al.
1994, pp. 67; 118), Salvato (1999, p. 117) found few documented field
sighting records or museum collection specimens from areas north of
Monroe and Miami-Dade Counties, suggesting that they may not have been
common further north historically (Salvato and Hennessey 2003, p. 243;
2004, p. 223).
Current Ranges
Populations of Florida leafwing and Bartram's scrub-hairstreak have
become increasingly localized as pine rockland habitat has been lost or
altered through anthropogenic activity (Lenczewski 1980, p. 43; Baggett
1982, p. 78; Hennessey and Habeck 1991, p. 4; Schwarz et al. 1996, p.
59; Salvato and Hennessey 2003, p. 243; Salvato and
[[Page 49884]]
Hennessey 2004, p. 223; Salvato and Salvato 2010a, p. 91; 2010b, p.
154). Long Pine Key in ENP retains the largest undisturbed tracts of
pine rockland habitat totaling an estimated 2,313 hectares (ha) (5,716
acres (ac)) on the mainland (Salvato 1999, p. 3; Service 1999, p. 173;
Salvato and Hennessey 2004, p. 223). Hennessey and Habeck (1991, p. 4)
and Salvato (1999, p. 3) estimated that approximately 1,068 ha (2,638
ac) of appropriate croton-bearing pine rockland habitat occur within
Long Pine Key. More recently, ENP fire effects staff have been
systematically mapping current pineland croton abundance, distribution,
and health throughout Long Pine Key (Land, pers. comm. 2012a; Sadle,
pers. comm. 2013c). As of early 2013, approximately 12.5 kilometers
(km) (7.7 miles (mi)) of pine rocklands have been evaluated and the
hostplant has been documented consistently throughout Long Pine Key.
In Miami-Dade County, outside of ENP, approximately 375 pine
rockland habitat fragments remain totaling approximately 1,780 ha
(4,398 ac) in 1999 (Service 1999, p. 173). Several of these fragments,
particularly those adjacent to ENP, such as Navy Wells and Richmond
Pine Rocklands (a mixture of publically and privately owned lands),
maintain localized populations of pineland croton as well as small or
sporadic occurrences of Bartram's scrub-hairstreak (Salvato 1999, p.
123; Salvato and Hennessey 2004, p. 223; Salvato and Salvato 2010b, p.
154). However, Salvato and Hennessey (2003, p. 243) and Salvato (pers.
comm. 2008) have generally failed to observe the Florida leafwing in
these or other relict (surviving remnant) pine rockland areas outside
ENP. During June 2007, one adult leafwing was observed within Navy
Wells (Salvato, pers. comm. 2008); however, no evidence of larval
activity was encountered suggesting this observation was a stray
occurrence. In addition, no leafwing have been recorded outside of ENP
since that time.
Breeding Florida leafwing populations have not been documented in
pine rockland fragments adjacent to ENP for the past 25 years. The
smallest of the former breeding populations was Navy Wells Pineland
Preserve (Navy Wells) (owned and managed by Miami-Dade County), which
is approximately 120 ha (296 ac) in size. The hairstreak retains
breeding populations on Big Pine Key, on Long Pine Key in ENP, and
within a number of pine rockland fragments adjacent to ENP, the
smallest of which is approximately 7 ha (18 ac) in size. It is possible
that leafwings require relatively larger patches of croton-bearing pine
rockland habitat to persist than do hairstreaks. Although larger
patches of habitat may be more suitable for these butterflies, the
relationship between habitat patch size and suitability is not
completely understood.
A geographic information system (GIS) analysis conducted by the
Service using data collected by The Institute for Regional Conservation
(IRC) in 2004 indicates that 65 pine rockland fragments (of various
sizes but at least 1 hectare) containing pineland croton remain in
private ownership in Miami-Dade County totaling approximately 190 ha
(470 ac) (IRC 2006, page numbers not applicable). Another 12 fragments
totaling 180 ha (446 ac) contain the croton and are in public ownership
(IRC 2006, page numbers not applicable). In 2012, the Service funded
Fairchild Tropical Botanic Gardens (FTBG) to conduct extensive surveys
of Miami-Dade pine rockland fragments in order to determine current
pineland croton abundance and distribution. Initial results from these
surveys are expected in 2013.
In the lower Florida Keys, Big Pine Key retains the largest
undisturbed tracts of pine rockland habitat totaling an estimated 560
ha (1,382 ac) (Zhang et al. 2010, p. 15; Roberts, pers. comm. 2012). At
present, within the Florida Keys pineland croton is known to occur only
on Big Pine Key. The last reports of the hostplant from other keys were
from those adjacent to Big Pine Key on No Name Key in 1992 (Carlson et
al. 1993, p. 923) and Little Pine Key in 1988 (Hennessey and Habeck
1991, p. 4). Recent surveys of relict pineland throughout the lower
Florida Keys by Hennessey and Habeck (1991, p. 4), Emmel et al. (2005,
p. 6), and Salvato (1999, p. 28; pers. comm. 2008) failed to locate the
plant from any island other than Big Pine Key. The staff at National
Key Deer Refuge (NKDR) estimated that approximately 243 ha (600 ac) of
croton-bearing pineland exist on public lands on Big Pine Key (C.
Anderson, pers. comm. 2012a). However, surveys indicate that only about
13 ha (32 ac) are regularly occupied by Bartram's scrub-hairstreak (C.
Anderson, pers. comm. 2013). In addition, many of the plants in these
areas show signs of senescence (growing older) (C. Anderson, pers.
comm. 2013). Although the Bartram's scrub-hairstreak is extant on Big
Pine Key, the Florida leafwing has not been seen on the island since
2006 (Minno and Minno 2009, pp. v, 9; Salvato and Salvato 2010c, p.
139).
Population Estimates and Status
Florida Leafwing
Based on results of all historical (Baggett 1982, p. 78; Schwartz
1987, p. 22; Hennessey and Habeck 1991, p. 17; Worth et al. 1996, p.
62; Schwarz et al. 1996, p. 59) and recent surveys and natural history
studies (Salvato 1999, p. 1; 2001, p. 8; 2003, p. 53; Salvato and
Hennessey 2003, p. 243; Salvato and Salvato 2010a, p. 91), the Florida
leafwing is extant in ENP and, until recently, had occurred on Big Pine
Key and historically in pineland fragments in mainland Miami-Dade
County (Smith et al. 1994, p. 67; Salvato and Salvato 2010a, p. 91;
2010c, p. 139). Schwartz (1987, pp. 1-19), Hennessey and Habeck (1991,
pp. 1-75), Emmel et al. (1995, pp. 5-7), and Salvato (1999, pp. 1-168)
searched the lower Florida Keys extensively for the Florida leafwing,
only encountering the butterfly on Big Pine Key. The butterfly's only
remaining metapopulation (a series of small populations that have some
level of interactions) at Long Pine Key within ENP has been well
documented, (Hennessey and Habeck 1991, pp. 1-75; Smith et al. 1994, p.
67; Emmel et al. 1995, pp. 5-7; Salvato and Salvato 2010a, pp. 91-97).
Results from all known historical surveys are provided in table 1. More
recent studies are discussed below.
Table 1--Summary of Historic Florida Leafwing Surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
Size or density numbers
Population Ownership Years of adult butterflies Source
--------------------------------------------------------------------------------------------------------------------------------------------------------
National Key Deer Refuge--Big Pine Key Federal--USFWS........... 1985-1986 34 observed or collected. Schwartz (1987, p. 25).
National Key Deer Refuge--Watson Federal--USFWS........... 1988-1989 3.7 per ha (1.5 per acre) Hennessey and Habeck (1991, pp. 1-75).
Hammock.
[[Page 49885]]
Everglades National Park--Long Pine Federal--NPS............. 1988-1989 3.7 per ha (1.5 per acre) Hennessey and Habeck (1991, pp. 1-75).
Key.
Everglades National Park--Long Pine Federal--NPS............. 1994-1995 22 observed.............. Emmel et al. (1995, p. 14).
Key.
National Key Deer Refuge--Big Pine Key Federal--USFWS........... 1994-1995 19 observed.............. Emmel et al. (1995, p. 14).
National Key Deer Refuge--Watson Federal--USFWS........... 1997-1998 3.1 per ha (1.2 per acre) Salvato (1999, p. 52).
Hammock.
Everglades National Park--Long Pine Federal--NPS............. 1997-1998 2.4 per ha (1 per acre).. Salvato (1999, p. 52).
Key.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Surveys by Salvato and Salvato (2010c, pp. 139-140) indicate the
average number of adult Florida leafwings recorded annually on Big Pine
Key declined from a high of 11 per ha (4.4 per ac) in 1999 to 0 from
late 2006 onward, based on monthly (1999 to 2006) or quarterly (2007 to
2012) surveys. Similar studies in Long Pine Key indicated that the
average number of leafwings recorded annually ranged from a high of
22.5 per ha (9 per ac) (1999) to 1.5 per ha (0.6 per ac) (2005), based
on monthly surveys conducted from 1999 through 2008 (Salvato and
Salvato 2010a, p. 93).
Ongoing surveys conducted by Salvato (pers. comm. 2012) from 2009
to 2012 have recorded an average abundance of 2.6 adult Florida
leafwings per ha (1 per ac), in Long Pine Key in ENP. In addition,
Salvato and Salvato (2010a, p. 96) and Salvato (pers. comm. 2012) have
encountered leafwing populations elsewhere within Long Pine Key as well
as adjacent habitats within ENP (Palma Vista Hammock and several former
agricultural and military lands) during 2005 to 2012. ENP staff also
monitors leafwing larval densities at several transects within Long
Pine Key monthly as part of studies on the recovery time of pineland
croton in response to prescribed burns (Land, pers. comm. 2012a).
Ongoing surveys conducted by ENP staff from 2005 to present have
encountered approximately 34 and 216 leafwing adults and larvae,
respectively, throughout Long Pine Key (Land, pers. comm. 2012a; Sadle,
pers. comm. 2013b).
No leafwings have been documented on Big Pine Key in the Florida
Keys since 2006 (Salvato and Salvato 2010c, p. 139). On the mainland,
Salvato (pers. comm. 2012) has found that the extant leafwing
population within ENP is maintained at several hundred or fewer,
although it varies greatly depending upon season and other factors.
However, Minno (pers. comm. 2009) estimated the extant leafwing
population size at less than 100 at any given period.
In ENP, the butterfly is most often encountered from late fall
through spring, and less abundantly during the summer (Salvato and
Salvato 2010a, p. 95; Land, pers. comm. 2012b). However, the leafwing
appeared to maintain a consistent year-round phenology (reproductive
life cycle) when it occurred on Big Pine Key (Salvato and Salvato
2010a, p. 95; 2010c, p. 140), with a slight peak in abundance during
the summer. Ongoing natural history studies of the leafwing by Salvato
and Salvato (Salvato, pers. comm. 2012) designed to evaluate mortality
factors amongst the butterfly's immature stages have identified a suite
of predators, parasitoids, and pathogens that may substantially
influence annual variability.
Bartram's Scrub-Hairstreak
Based on the results of historic (Baggett 1982, p. 80; Schwartz
1987, p. 16; Hennessey and Habeck 1991, pp. 117-119; Smith et al. 1994,
p. 118; Emmel et al. 1995, pp. 1-24; Worth et al. 1996, pp. 62-65;
Schwarz et al. 1996, pp. 59-61) and recent (Salvato 1999, p. 1; 2001,
p. 8; 2003, p. 53; Salvato and Hennessey 2004, p. 223; Minno and Minno
2009, p. 76; Salvato and Salvato 2010b, p. 154; C. Anderson pers. comm.
2012a; Land pers. comm. 2012a) surveys and natural history studies,
there are extant Bartram's scrub-hairstreak metapopulations in ENP and
locally within pineland fragments in mainland Miami-Dade County, and on
Big Pine Key in Monroe County. Results from all known historical
surveys are provided in table 2. More recent studies are discussed
below.
Table 2--Summary of Historic Bartram's Scrub-Hairstreak Surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
Size or density numbers
Population Ownership Years of adult butterflies Source
--------------------------------------------------------------------------------------------------------------------------------------------------------
National Key Deer Refuge--Big Pine Key Federal--USFWS........... 1985-1986 20 observed or collected. Schwartz (1987, p. 16).
National Key Deer Refuge--Big Pine Key Federal--USFWS........... 1988-1989 3.9 per ha (1.6 per ac).. Hennessey and Habeck (1991, pp. 49-50).
Everglades National Park--Long Pine Federal--NPS............. 1988-1989 0.5 per ha (0.2 per ac).. Hennessey and Habeck (1991, pp. 49-50).
Key.
Everglades National Park--Long Pine Federal--NPS............. 1994-1995 7 observed............... Emmel et al. (1995, p. 14).
Key.
National Key Deer Refuge--Big Pine Key Federal--USFWS........... 1994-1995 9 observed............... Emmel et al. (1995, p. 14).
National Key Deer Refuge--Big Pine Key Federal--USFWS........... 1997-1998 4.3 per ha (1.7 per ac).. Salvato (1999, p. 52).
Everglades National Park--Long Pine Federal--NPS............. 1997-1998 0 per ha (0 per ac)...... Salvato (1999, p. 60).
Key.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ongoing surveys by Salvato and Salvato (unpublished data) indicate
the average number of adult Bartram's scrub-hairstreaks recorded
annually on Big Pine Key has declined considerably, from a high of 19.3
per ha (7.7 per ac) in 1999 to a low of less than 1 per ha (0.3 per ac)
in 2011, based on monthly (1999-2006) or quarterly (2007 to 2012)
surveys. Minno and Minno (2009, p. 76) recorded an average of 35 adults
annually on Big Pine Key during
[[Page 49886]]
monthly surveys conducted from 2006 to 2009. Recent annual North
American Butterfly Association (NABA) ``Fourth of July'' counts on Big
Pine Key reported zero and one individual hairstreaks during 2011 and
2012, respectively.
In order to more frequently survey hairstreak populations within
NKDR, the Service, from 2010 to 2012, has implemented a standardized
monitoring method to monitor the butterfly at three core pine rockland
locations across Big Pine Key (C. Anderson, pers. comm. 2012a). Since
that time, the mean monthly count across sites has ranged from 0.0 to
2.8 (with a standard error of 0.33) adult hairstreaks per
ha (C. Anderson, pers. comm. 2012a). The maximum adult counts were 15
and 8 adults per ha for 2010 and 2011, respectively; however, the means
were not significantly different between years (C. Anderson, pers.
comm. 2012a). These densities are much higher than those encountered by
Salvato and Salvato (unpublished data) in 2010 and 2011; this disparity
may be due to the fact that NKDR has established survey transects at
locations with more optimal hostplant abundance, where the latter
studies continue to monitor long-term transects (15 to 25 years) that
were historic strongholds for the butterfly, but have since become
degraded. In other words, NKDR is monitoring at what may be current
strongholds, while Salvato and Salvato are documenting the butterfly's
status at former strongholds. Since early 2012, North Carolina State
University personnel have collaborated with the Service to access
detection probabilities, estimate abundances, and measure vegetation
characteristics associated with butterfly populations on NKDR.
Due in large part to the benefits of an effective and systematic
burn plan in ENP, Salvato and Salvato (2010b, p. 159) and Salvato
(pers. comm. 2012) have encountered as many as 6.3 adult Bartram's
scrub-hairstreaks per ha (2.5 per acre) annually from 1999 to 2012,
based on monthly surveys in Long Pine Key. In addition, Salvato and
Salvato (2010b, p. 156) and Salvato (pers. comm. 2012) have also
monitored populations of the Bartram's scrub-hairstreak elsewhere
within Long Pine Key during 2005-2012 and encountered similar
densities. Ongoing surveys conducted by ENP staff from 2005 to present
have encountered a total of approximately 24 and 30 hairstreak adults
and larvae, respectively, throughout Long Pine Key (Land, pers. comm.
2012a; Sadle, pers. comm. 2013b).
Additional pine rockland fragments within Miami-Dade County that
are known to maintain small, localized populations of pineland croton
and sporadic occurrences of Bartram's scrub-hairstreak, based on
limited survey work, include: Navy Wells (120 ha (297 acres)), Camp
Owaissa Bauer (39 ha (99 ac)) (owned and managed by Miami-Dade County),
and several parcels within the Richmond Pine Rocklands, including:
Larry and Penny Thompson Memorial Park (109 ha (270 ac)), Miami Metro
Zoo Preserve (300 ha (740 ac)), Martinez Pineland Park (53 ha (132
ac)), and Coast Guard lands in Homestead (29 ha (72 ac)) (Minno and
Minno 2009, pp. 70-76; J. Possley, FTBG, pers. comm. 2010).
Summary of Factors Affecting the Species
Section 4 of the Act (16 U.S.C. 1533), and its implementing
regulations at 50 CFR part 424, set forth the procedures for adding
species to the Federal Lists of Endangered and Threatened Wildlife and
Plants. Under section 4(a)(1) of the Act, we may list a species based
on any of the following 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. Listing actions may be warranted
based on any of the above threat factors, singly or in combination.
Each of these factors is discussed below.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
Habitat Loss
The Florida leafwing and Bartram's scrub-hairstreak have
experienced substantial destruction, modification, and curtailment of
their habitat and range (see Status Assessment section). The pine
rockland community of south Florida, on which both butterflies and
their hostplant depend, is critically imperiled globally (FNAI 2012, p.
27). Destruction of the pinelands for economic development has reduced
this habitat community by 90 percent on mainland south Florida (O'Brien
1998, p. 208). All known mainland populations of the Florida leafwing
and Bartram's scrub-hairstreak occur on publicly or privately owned
lands that are managed for conservation (table 3). However, any unknown
extant populations of these butterflies or suitable habitat that may
occur on private land or nonconservation public land, such as within
the Richmond Pine Rocklands, are vulnerable to habitat loss.
Table 3--Land Ownership of Extant Florida Leafwing and Bartram's Scrub-Hairstreak Populations
----------------------------------------------------------------------------------------------------------------
Location Ownership Size
----------------------------------------------------------------------------------------------------------------
Bartram's Scrub-Hairstreak
----------------------------------------------------------------------------------------------------------------
Big Pine Key......................... Public--Fish and Wildlife 559 ha (1,382 ac).
Service.
Public--Monroe County........
Public--FDEP, FWC............
Private......................
Everglades National Park--Long Pine Federal--National Park 8,029 ha (19,840 ac).
Key. Service.
Navy Wells Pineland Preserve......... Public--Miami-Dade County.... 142 ha (353 ac).
Camp Owaissa Bauer................... Public--Miami-Dade County.... 40 ha (99 ac).
Richmond Pine Rocklands.............. Public--Federal (Coast Guard) 359 ha (889 acres).
----------------------------------------------------------------------------------------------------------------
Public--Miami-Dade County
(Larry and Penny Thompson
Memorial Park, Martinez
Pineland Park, Miami Metro
Zoo Preserve).
Private-University of Miami..
----------------------------------------------------------------------------------------------------------------
[[Page 49887]]
Florida Leafwing
----------------------------------------------------------------------------------------------------------------
Everglades National Park--Long Pine Federal--National Park 8,029 ha (19,840 ac).
Key. Service.
----------------------------------------------------------------------------------------------------------------
Similarly, most of the ecosystems on the Florida Keys have been
impacted by humans, through widespread clearing of habitat in the 19th
century for farming, or building of homes and businesses; extensive
areas of pine rocklands have been lost (Hodges and Bradley 2006, p. 6).
Overall, the human population in Monroe County is expected to increase
from 79,589 to more than 92,287 people by 2060 (Zwick and Carr 2006, p.
21). All vacant land in the Florida Keys is projected to be developed
by then, including lands currently inaccessible for development, such
as islands not attached to the Overseas Highway (US 1) (Zwick and Carr
2006, p. 14). However, during 2006, Monroe County implemented a Habitat
Conservation Plan (HCP) for Big Pine and No Name Keys. Subsequently,
development on these islands has to meet the requirements of the HCP
with the resulting pace of development changed accordingly.
Furthermore, in order to fulfill the HCP's mitigation requirements, the
County has been actively acquiring parcels of high-quality pine
rockland, such as The Nature Conservancy's 20-acre Terrestris Tract on
Big Pine Key, and managing them for conservation. However, land
development pressure and habitat losses may resume when the HCP expires
in 2023. If the HCP is not renewed, residential or commercial
development could increase to pre-HCP levels. Consequently, remaining
suitable habitat for Bartram's scrub-hairstreak and potential habitat
for the Florida leafwing could be at significant risk to habitat loss
and modification. Further losses will seriously affect the hairstreak's
ability to persist in the wild and decrease the possibility of recovery
or recolonization by the leafwing.
Fire Management
The threat of habitat destruction or modification is further
exacerbated by a lack of adequate fire management (Salvato and Salvato
2010a, p. 91; 2010b, p. 154; 2010c, p. 139). Historically, lightning-
induced fires were a vital component in maintaining native vegetation
within the pine rockland ecosystem, including pineland croton (Loope
and Dunevitz 1981, p. 5; Slocum et al. 2003, p. 93; Snyder et al. 2005,
p. 1; Salvato and Salvato 2010b, p. 154). Resprouting after burns is
the primary mechanism allowing for the persistence of perennial shrubs,
including pineland croton, in pine habitat (Olson and Platt 1995, p.
101). Without fire, successional climax from tropical pineland to
hardwood hammock is rapid, and displacement of native species by
invasive nonnative plants often occurs.
Prescribed fire is used throughout the pine rocklands of Long Pine
Key (ENP) and has been consistently used for the past 50 years (Loope
and Dunevitz 1981, p. 5; Salvato and Salvato 2010b, p. 154). Little is
known about the fire history in ENP prior to 1947, and initially fires
were suppressed (Slocum et al. 2003, p. 93). Fire was reintroduced in
the late 1950s, but its role remained poorly understood (Slocum et al.
2003, p. 93). However, many of the prescribed burns conducted in Long
Pine Key during this earlier time period were quite extensive, with
several large areas treated simultaneously. ENP is currently in the
process of updating its Fire Management Plan (FMP) and Environmental
Assessment, which will assess the impacts of fire on various
environmental factors, including listed, proposed, and candidate
species (Land, pers. comm. 2011; Sadle, pers. comm. 2013a). Since 2001,
ENP fire staff has used partial and systematic prescribed burns to
treat the Long Pine Key pine rocklands in their entirety over a 3-year
window burning adjacent habitats alternately (National Park Service
(NPS) 2005, p. 27). Although this has resulted in restoration of
species-rich, herbaceous-dominated pine rocklands in many areas,
including resurgence of pineland croton, populations of this hostplant
appear fragmented (Salvato and Hennessey 2004, p. 223).
Cyclic and alternating treatment of burn units may have benefited
the Florida leafwing throughout Long Pine Key (Salvato and Salvato
2010a, pp. 91-97). The leafwing, with its strong flight abilities, can
disperse to make use of adjacent patches of hostplant and then quickly
recolonize burned areas following hostplant resurgence (Salvato 1999,
p. 5; 2003, p. 53; Salvato and Salvato 2010a, p. 95). Salvato and
Salvato (2010a, p. 95) encountered similar adult leafwing densities
pre- and postburn throughout their 10-year study within Long Pine Key,
suggesting the leafwing can quickly recolonize pine rocklands following
a fire. Surveys conducted shortly after burns often found adult
leafwings actively exploring the recently burned locations in search of
new hostplant growth (Land, pers. comm. 2009; Salvato and Salvato 2008,
p. 326; 2010a, p. 95). In most instances croton returned to the burned
parts of Long Pine Key within 1 to 3 months postburn; however, it may
take up to 6 months before the leafwing will use the new growth for
oviposition (Lenczewski 1980, p. 35; Land, pers. comm. 2009; Salvato
and Salvato 2010a, p. 95). Land (pers. comm. 2009) indicated that 96
percent of pineland croton burned during prescribed fires on Long Pine
Key had resprouted within a few months. Although Salvato and Salvato
(2010a, p. 96) occasionally encountered signs of leafwing reproduction
within recently burned Long Pine Key locations at approximately 6 weeks
postburn, the majority of their observations indicated that oviposition
and larval activity increased at about 3 to 6 months postburn.
Similarly, Land (pers. comm. 2009) reported finding leafwing larval
activity on resprouting croton at 6 months postburn. This finding
suggests there may be some lag time between hostplant resurgence and
compatibility with recolonization.
The influence of prescribed burns on the status and distribution of
the hairstreak and croton is being evaluated by ENP throughout Long
Pine Key. The effects of new burn techniques on the Bartram's scrub-
hairstreak within Long Pine Key were not immediately obvious (Salvato
and Salvato 2010b, p. 159). The hairstreak is rarely encountered more
than 5 m (16.4 ft) from its hostplant (Schwartz 1987, p. 16; Worth et
al. 1996, p. 65; Salvato and Salvato 2008, p. 324). Salvato and
Hennessey (2004, p. 224) and Salvato and Salvato (2010b, p. 159)
indicate that if the hairstreak is unable to disperse adequately during
fire events, then only adults at the periphery of burned areas are
likely to escape to adjacent pine rocklands. Ideally, as a result of
cyclic burns and multiyear treatment intervals, the
[[Page 49888]]
hairstreaks will move from the burned location to adjacent refugia
(i.e., unburned areas of croton hostplant) and then back to burned area
in numbers equal to or greater than before the fire. Starting in the
fall of 2004 and continuing into early 2006, the hairstreak appeared to
have benefited with population densities greater than those recorded in
any previous studies (Salvato and Salvato 2010b, p. 159), and this
trend has continued subsequently (Land pers. comm. 2011, 2012a; Salvato
pers. comm. 2012).
ENP is actively coordinating with the Service, as well as other
members of the Imperiled Butterfly Working Group to review and adjust
the prescribed burn practices outlined in the FMP to help maintain or
increase Florida leafwing and Bartram's scrub-hairstreak population
sizes, protect pine rocklands, expand or restore remnant patches of
hostplants and ensure that short-term negative effects from fire (i.e.,
loss of hostplants, loss of eggs and larvae) can be avoided or
minimized.
Outside of the ENP, Miami-Dade County has implemented various
conservation measures, such as burning in a mosaic pattern and on a
small scale, during prescribed burns in order to protect the
butterflies (Maguire, pers. comm. 2010). Miami-Dade County Parks and
Recreation staff has burned several of their conservation lands on a
fire return interval of approximately 3 to 7 years. In addition,
prescribed burns on large conservation areas, such as Navy Wells, have
been conducted in a cyclic and systematic pattern, which has provided
refugia within or adjacent to treatment areas. As a result, the
Bartram's scrub-hairstreak has retained populations within many of
these County-managed conservation lands.
Recent natural or prescribed fire activity on Big Pine Key and
adjacent islands within NKDR appears to be insufficient to prevent loss
of pine rockland habitat (Carlson et al. 1993, p. 914; Bergh and Wisby
1996, pp. 1-2; O'Brien 1998, p. 209; Snyder et al. 2005; Bradley and
Saha 2009, pp. 28-29; Bradley et al. 2011, pp. 1-16). As a result, many
of the pine rocklands, across NKDR are being compromised by succession
to hardwood hammock (Bradley and Saha 2009, pp. 28-29; Bradley et al.
2011, pp. 1-16). Pineland croton, which was historically documented
from No Name and Little Pine Keys (Dickson 1955, p. 98; Hennessey and
Habeck 1991, p. 4; Carlson et al. 1993, p. 923), is now absent from
these locations (Emmel et al. 1995, p. 6; Salvato and Salvato 2010c, p.
139).
Fire management of pine rocklands in NKDR is hampered by the
pattern of land ownership and development; residential and commercial
properties are embedded within or in close proximity to pineland
habitat (Snyder et al. 2005, p. 2; C. Anderson, pers. comm. 2012a). As
a result, hand or mechanical vegetation management may be necessary at
select locations on Big Pine Key (Emmel et al. 1995, p. 11; Minno,
pers. comm. 2009; Service 2010, pp. 1-68) to maintain or restore pine
rocklands. Clearing, such as that used to create firebreaks, can result
in high croton densities. Anderson et al. (2012, page numbers not
applicable) showed that croton densities were significantly higher in a
fire break with annual mechanical treatments than adjacent areas with
no management. However, even within fire breaks, hostplant density
across NKDR has declined considerably in some areas over the past
decade. Salvato and Salvato (unpublished data) have noted as much as a
100 percent loss of pineland croton from several of their long-term
survey transects, which occur within both firebreaks and forested pine
rocklands. These losses are believed to be due to a combination of
mowing activity, habitat modification, and a lack of adequate fire
management. Mechanical treatments may be less beneficial than fire
because they do not quickly convert debris to nutrients, and remaining
leaf litter may suppress croton seedling development; fire has also
been found to stimulate seedling germination (C. Anderson, pers. comm.
2010). Because mechanical treatments may not provide the same
ecological benefits as fire, NKDR continues to focus efforts on
conducting prescribed fire where possible (C. Anderson, pers. comm.
2012a).
The NKDR is attempting to increase the density of hostplants within
their pine rockland habitat through the use of prescribed fire.
However, the majority of pine rocklands within NKDR are several years
departed from the ideal fire return interval (5-7 years) suggested for
this ecosystem (Synder et al. 2005, p. 2, Bradley and Saha 2011, pp. 1-
16). Tree ring and sediment data show that pine rocklands in the lower
Keys have burned at least every 5 years and sometimes up to three times
per decade historically (Albritton 2009, pp. 123, Horn et.al., 2013,
pp. 1-67, Harley 2012, pp. 1-246). Prescribed fire implementation in
the lower Keys has been hampered largely due to a shortage of
resources, technical challenges, and expense of conducting prescribed
fire in a matrix of public and private ownership. However, NKDR is
taking steps to monitor croton before and after fire, provide refugia
during treatments, and ensure that appropriate corridors are maintained
during burns (C. Anderson, pers. comm. 2010). Given the difficulties in
prescribed fire implementation on Big Pine Key, other options have been
explored to increase the amount of available hostplant for extant
Bartram's scrub-hairstreak populations, as well as to restore formerly
occupied Florida leafwing habitat on Big Pine Key. For example, NKDR
currently is growing pineland croton for use in habitat enhancement
activities across the Refuge (more than a thousand have been planted to
date) (C. Anderson pers. comm. 2012b).
Climate Change and Sea Level Rise Related to Habitat Loss and
Alteration
Climatic changes, including sea level rise, are major threats to
south Florida, including the Florida leafwing and Bartram's scrub-
hairstreak. Our analyses under the Act include consideration of ongoing
and projected changes in climate. The terms ``climate'' and ``climate
change'' are defined by the Intergovernmental Panel on Climate Change
(IPCC). The term ``climate'' refers to the mean and variability of
different types of weather conditions over time, with 30 years being a
typical period for such measurements, although shorter or longer
periods also may be used (IPCC 2007a, p. 78). The term ``climate
change'' thus refers to a change in the mean or variability of one or
more measures of climate (e.g., temperature or precipitation) that
persists for an extended period, typically decades or longer, whether
the change is due to natural variability, human activity, or both (IPCC
2007a, p. 78).
Scientific measurements spanning several decades demonstrate that
changes in climate are occurring, and that the rate of change has been
faster since the 1950s. Examples include warming of the global climate
system, and substantial increases in precipitation in some regions of
the world and decreases in other regions. (For these and other
examples, see IPCC 2007a, p. 30; and Solomon et al. 2007, pp. 35-54,
82-85). Results of scientific analyses presented by the IPCC show that
most of the observed increase in global average temperature since the
mid-20th century cannot be explained by natural variability in climate,
and is ``very likely'' (defined by the IPCC as 90 percent or higher
probability) due to the observed increase in greenhouse gas (GHG)
concentrations in the atmosphere as a result of human activities,
particularly carbon dioxide emissions
[[Page 49889]]
from use of fossil fuels (IPCC 2007a, pp. 5-6 and figures SPM.3 and
SPM.4; Solomon et al. 2007, pp. 21-35). Further confirmation of the
role of GHGs comes from analyses by Huber and Knutti (2011, p. 4), who
concluded it is extremely likely that approximately 75 percent of
global warming since 1950 has been caused by human activities.
Scientists use a variety of climate models, which include
consideration of natural processes and variability, as well as various
scenarios of potential levels and timing of GHG emissions, to evaluate
the causes of changes already observed and to project future changes in
temperature and other climate conditions (e.g., Meehl et al. 2007,
entire; Ganguly et al. 2009, pp. 11555, 15558; Prinn et al. 2011, pp.
527, 529). All combinations of models and emissions scenarios yield
very similar projections of increases in the most common measure of
climate change, average global surface temperature (commonly known as
global warming), until about 2030. Although projections of the
magnitude and rate of warming differ after about 2030, the overall
trajectory of all the projections is one of increased global warming
through the end of this century, even for the projections based on
scenarios that assume that GHG emissions will stabilize or decline.
Thus, there is strong scientific support for projections that warming
will continue through the 21st century, and that the magnitude and rate
of change will be influenced substantially by the extent of GHG
emissions (IPCC 2007a, pp. 44-45; Meehl et al. 2007, pp. 760-764 and
797-811; Ganguly et al. 2009, pp. 15555-15558; Prinn et al. 2011, pp.
527, 529). See IPCC (2007b, p. 8), for a summary of other global
projections of climate-related changes, such as frequency of heat waves
and changes in precipitation. Also see IPCC 2011 (entire) for a summary
of observations and projections of extreme climate events.
Various changes in climate may have direct or indirect effects on
species. These effects may be positive, neutral, or negative, and they
may change over time, depending on the species and other relevant
considerations, such as interactions of climate with other variables
(e.g., habitat fragmentation) (IPCC 2007, pp. 8-14, 18-19). Identifying
likely effects often involves aspects of climate change vulnerability
analysis. Vulnerability refers to the degree to which a species (or
system) is susceptible to, and unable to cope with, adverse effects of
climate change, including climate variability and extremes.
Vulnerability is a function of the type, magnitude, and rate of climate
change and variation to which a species is exposed, its sensitivity,
and its adaptive capacity (IPCC 2007a, p. 89; see also Glick et al.
2011, pp. 19-22). There is no single method for conducting such
analyses that applies to all situations (Glick et al. 2011, p. 3). We
use our expert judgment and appropriate analytical approaches to weigh
relevant information, including uncertainty, in our consideration of
various aspects of climate change.
Global climate projections are informative, and, in some cases, the
only or the best scientific information available for us to use.
However, projected changes in climate and related impacts can vary
substantially across and within different regions of the world (e.g.,
IPCC 2007a, pp. 8-12). Therefore, we use ``downscaled'' projections
when they are available and have been developed through appropriate
scientific procedures, because such projections provide higher
resolution information that is more relevant to spatial scales used for
analyses of a given species (see Glick et al. 2011, pp. 58-61, for a
discussion of downscaling).
With regard to our analysis for the Florida leafwing and Bartram's
scrub-hairstreak, downscaled projections suggest that sea level rise is
the largest climate-driven challenge to low-lying coastal areas and
refuges in the subtropical ecoregion of southern Florida (U.S. Climate
Change Science Program (CCSP) 2008, pp. 5-31, 5-32). The long-term
record at Key West shows that sea level rose on average 0.224
centimeters (cm) (0.088 in) annually between 1913 and 2006 (National
Oceanographic and Atmospheric Administration (NOAA) 2008, p. 1). This
equates to approximately 22.3 cm (8.76 in) over the last 100 years
(NOAA 2008, p. 1). IPCC (2008, p. 28) emphasized it is very likely that
the average rate of sea level rise during the 21st century will exceed
that rate, although it was projected to have substantial geographical
variability.
Other processes to be affected by projected warming include
temperatures, rainfall (amount, seasonal timing, and distribution), and
storms (frequency and intensity). The Massachusetts Institute of
Technology (MIT) modeled several scenarios combining various levels of
sea level rise, temperature change, and precipitation differences with
population, policy assumptions, and conservation funding changes. All
of the scenarios, from small climate change shifts to major changes,
indicate significant effects on the Florida Keys.
The Nature Conservancy (TNC) modeled several scenarios for the
Florida Keys, and predicted that sea level rise will first result in
the conversion of habitat, and eventually the complete inundation of
habitat. In the best-case scenario, by the year 2100, a rise of 18 cm
(7 in) would result in the inundation of 745 ha (1,840 ac) (34 percent)
of Big Pine Key and the loss of 11 percent of the island's upland
habitat (TNC 2010, p. 1). In the worst-case scenario, a rise of 140 cm
(4.6 ft would result in the inundation of about 2,409 ha (5,950 ac) (96
percent) and the loss of all upland habitat on the Key (TNC 2010, p.
1). Extant populations of Bartram's scrub-hairstreak in the pine
rocklands on Big Pine Key are located just slightly above mean sea
level, and saturation or increase in salinity of the soil would
correspondingly change the vegetation and habitat structure making the
butterfly's survival at this location in the Keys very unlikely. In
addition, the Florida leafwing also occurred on Big Pine Key until
2006, within the same locations as extant Bartram's scrub-hairstreak
populations. Re-establishment of the Florida leafwing to this island
will be a major component in recovering the butterfly. The loss of this
portion of the Florida leafwing's range will further reduce their
overall resiliency to threats and limit their capacity for survival and
recovery.
Hydrology has a strong influence on plant distribution in these and
other coastal areas (IPCC 2008, p. 57). Such communities typically
grade from salt to brackish to freshwater species. From the 1930s to
1950s, increased salinity of coastal waters contributed to the decline
of cabbage palm forests in southwest Florida (Williams et al. 1999, pp.
2056-2059), expansion of mangroves into adjacent marshes in the
Everglades (Ross et al. 2000, pp. 9, 12-13), and loss of pine rockland
in the Keys (Ross et al. 1994, pp. 144, 151-155). Furthermore, Ross et
al. (2009, pp. 471-478) suggested that interactions between sea level
rise and pulse disturbances (e.g., storm surges) can cause vegetation
to change sooner than projected based on sea level alone. Alexander
(1953, pp. 133-138) attributed the demise of pinelands on northern Key
Largo to salinization of the groundwater in response to sea level rise.
Patterns of human development will also likely be significant factors
influencing whether natural communities can move and persist (IPCC
2008, p. 57; CCSP 2008, p. 7-6).
Drier conditions and increased variability in precipitation
associated with climate change are expected to hamper successful
regeneration of
[[Page 49890]]
forests and cause shifts in vegetation types through time (Wear and
Greis 2011, p. 58). Climate changes are forecasted to extend fire
seasons and the frequency of large fire events throughout the Coastal
Plain (Wear and Greis 2011, p. 65). Increases in the scale, frequency,
or severity of wildfires could also have severe ramifications on the
Florida leafwing and Bartram's scrub-hairstreak, considering their
dependence on pine rocklands and general vulnerability due to their
reduced population size, restricted range, few colonies, low fecundity,
and relative isolation (see Factor E).
The ranges of recent projections of global sea level rise (Pfeffer
et al. 2008, p. 1340; Vermeer and Rahmstorf 2009, p. 21530; Grinsted et
al. 2010, pp. 469-470; Jevrejeva et al. 2010, Global Climate Change
Impacts in the United States 2009, pp. 25-26) all indicate
substantially higher levels than the projection by the IPCC in 2007,
suggesting that the impact of sea level rise on south Florida could be
even greater than indicated above. These recent studies also show a
much larger difference (approximately 0.9 to 1.2 m (3 to 4 ft)) from
the low to the high ends of the ranges, which indicates that the
magnitude of global mean sea level rise at the end of this century is
still quite uncertain.
Alternative Future Landscape Models
Various model scenarios developed at MIT have projected possible
trajectories of future transformation of the south Florida landscape by
2060 based upon four main drivers: climate change, shifts in planning
approaches and regulations, human population change, and variations in
financial resources for conservation (Vargas-Moreno and Flaxman 2010,
pp. 1-6). The Service used various MIT scenarios in combination with
extant and historic Florida leafwing and Bartram's scrub-hairstreak
occurrences and remaining hostplant-bearing pine rocklands to predict
what may occur to the butterflies and their habitat.
In the best-case scenario, which assumes low sea level rise, high
financial resources, proactive planning, and only trending population
growth, analyses suggest that the Big Pine Key population of the
Bartram's scrub-hairstreak may be lost or greatly reduced. Based upon
the above assumptions, extant butterfly populations on Big Pine Key
(Bartram's scrub-hairstreak) and Long Pine Key (Florida leafwing and
Bartram's scrub-hairstreak) appear to be most susceptible for future
losses, with losses attributed to increases in sea level and human
population. In the worst-case scenario, which assumes high sea level
rise, low financial resources, a ``business as usual'' approach to
planning, and a doubling of human population, the habitat at Big Pine
Key and Long Pine Key may be lost and the loss of habitat at Long Pine
Key resulting in the complete extirpation of the Florida leafwing.
Under the worst-case scenario, pine rockland habitat would remain
within both Navy Wells and the Richmond Pine Rocklands, both of which
currently retain Bartram's scrub-hairstreak populations. Actual impacts
may be greater or less than anticipated based upon high variability of
factors involved (e.g., sea level rise, human population growth) and
assumptions made.
Everglades Restoration
Projects designed to restore the historic hydrology of the
Everglades and other natural systems in southern Florida (collectively
known as the Comprehensive Everglades Restoration Project (CERP)) may
produce collateral impacts to extant pine rockland within Long Pine
Key. Salvato (pers. comm. 2012) noted substantial flooding of pine
rocklands at the gate 11 nature trail in Long Pine Key following
Hurricane Isaac (August 2012) and subsequent above-average rainfall in
the region. Although Long Pine Key has experienced storm damages in the
recent past (Salvato and Salvato 2010a, p. 96), none of the prior
activity produced the level (several feet) or duration (more than 2
months) of inundation noted in the aftermath of Isaac. However, by mid-
December 2012, Salvato noted no apparent lasting influence on croton
health or abundance from the inundation. Sadle (pers. comm. 2012)
suggests various CERP projects (C-111 spreader canal; L-31N seepage
barrier), specifically the operation of pumps and associated detention
areas along the ENP boundary, may influence select portions of eastern
Long Pine Key, including pineland croton populations at gate 11.
However, Pace (pers. comm. 2013) attributed the pine rockland flooding
event of late 2012 more to localized and above-average rainfall
patterns than to a change in water management practices. Analysis of
the hydrology associated with operation of these CERP-related
structures along the Everglades boundary will be conducted following
the initial years of operation. However, Service and NPS biologists
realize the need to assess this potential threat.
Conservation Efforts To Reduce the Present or Threatened Destruction,
Modification, or Curtailment of Its Habitat or Range
The National Wildlife Refuge System Improvement Act of 1997 and the
Fish and Wildlife Service Manual (601 FW 3, 602 FW 3) require
maintaining biological integrity and diversity, comprehensive
conservation planning for each refuge, and set standards to ensure that
all uses of refuges are compatible with their purposes and the Refuge
System's wildlife conservation mission. The comprehensive conservation
plans (CCP) address conservation of fish, wildlife, and plant resources
and their related habitats, while providing opportunities for
compatible wildlife-dependent recreation uses. An overriding
consideration reflected in these plans is that fish and wildlife
conservation has first priority in refuge management, and that public
use be allowed and encouraged as long as it is compatible with, or does
not detract from, the Refuge System mission and refuge purpose(s). The
CCP for the Lower Florida Keys National Wildlife Refuges (NKDR, Key
West National Wildlife Refuge, and Great White Heron National Wildlife
Refuge) provides a description of the environment and priority resource
issues that were considered in developing the objectives and strategies
that guide management over the next 15 years. The CCP promotes the
enhancement of wildlife populations by maintaining and enhancing a
diversity and abundance of habitats for native plants and animals,
especially imperiled species that are found only in the Florida Keys.
The CCP also provides for obtaining baseline data and monitoring
indicator species to detect changes in ecosystem diversity and
integrity related to climate change. In the Lower Key Refuges, CCP
management objective no. 11 provides specifically for maintaining and
restoring butterfly populations of special conservation concern,
including the Bartram's scrub-hairstreak and Florida leafwing
butterflies.
As Federal candidates, the Florida leafwing and Bartram's scrub-
hairstreak are afforded some protection through sections 7 and 10 of
the Act and associated policies and guidelines. Service policy requires
candidate species be treated as proposed species for purposes of intra-
Service consultations and conferences where the Service's actions on
National Wildlife Refuges may affect candidate species. Federal action
agencies (e.g., Service, NPS) are to consider the potential effects
(e.g., prescribed fire,
[[Page 49891]]
pesticide treatments) to these butterflies and their habitat during the
consultation and conference process. Applicants and action agencies are
encouraged to consider candidate species when seeking incidental take
for other listed species and when developing habitat conservation
plans. However, candidate species do not receive the same level of
protection that a listed species would under the Act.
The NPS is also currently preparing a revised General Management
Plan for ENP (Sadle, NPS, pers. comm. 2013a). ENP's current Management
Plan (initiated in 1979) serves to protect, restore, and maintain
natural and cultural resources at the ecosystem level (NPS 2000, p.
10). The current GMP is not regulatory and its implementation is not
mandatory. In addition, this GMP does not specifically address either
the Florida leafwing or Bartram's scrub-hairstreak.
Fairchild Tropical Botanic Gardens (FTBG), with the support of
various Federal, State, local and nonprofit organizations, has
established the ``Connect to Protect Network.'' The objective of this
program is to encourage widespread participation of citizens to create
corridors of healthy pine rocklands by planting stepping-stone gardens
and rights-of-way with native pine rockland species, and restoring
isolated pine rockland fragments. By doing this, FTBG hopes to increase
the probability that pollinators can find and transport seeds and
pollen across developed areas that separate pine rocklands fragments to
improve gene flow between fragmented plant populations and increase the
likelihood that these species will persist over the long term. Although
this project may serve as a valuable component toward the conservation
of pine rockland species, it is dependent on continual funding, as well
as participation from private landowners, both of which may vary
through time.
Summary of Factor A
We have identified a number of threats to the habitat of the
Florida leafwing and Bartram's scrub-hairstreak that have operated in
the past, are impacting the butterflies now, and will continue to
impact these butterflies in the future. Habitat loss, fragmentation,
and degradation and associated pressures from increased human
population are major threats; these threats are expected to continue,
placing these butterflies at greater risk. Both butterflies may be
impacted when pine rocklands are converted to other uses or when lack
of fire causes the conversion to hardwood hammocks or other habitats
that are unsuitable for these butterflies and their host plant. Routine
land management activities (e.g., prescribed fire) may also cause
impacts to hostplant abundance and availability of nectar sources.
Environmental effects resulting from climatic change, including sea
level rise, are occurring now and are expected to become severe in the
future, resulting in additional habitat losses. Although efforts are
being made to conserve natural areas and apply prescribed fire, the
long-term effects of large-scale and wide-ranging habitat modification,
destruction, and curtailment will last into the future.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Collection
Rare butterflies and moths are highly prized by collectors, and an
international trade exists in specimens for both live and decorative
markets, as well as the specialist trade that supplies hobbyists,
collectors, and researchers (Collins and Morris 1985, pp. 155-179;
Morris et al. 1991, pp. 332-334; Williams 1996, pp. 30-37). The
specialist trade differs from both the live and decorative market in
that it concentrates on rare and threatened species (U.S. Department of
Justice (USDJ) 1993, pp. 1-3; United States v. Skalski et al., Case No.
CR9320137, U.S. District Court for the Northern District of California
(USDC) 1993, pp. 1-86). In general, the rarer the species, the more
valuable it is; prices can exceed $25,000 for exceedingly rare
specimens. For example, during a 4-year investigation, special agents
of the Service's Office of Law Enforcement executed warrants and seized
more than 30,000 endangered and protected butterflies and beetles, with
a total wholesale commercial market value of about $90,000 in the
United States (USDJ 1995, pp. 1-4). In another case, special agents
found at least 13 species protected under the Act, and another 130
species illegally taken from lands administered by the Department of
the Interior and other State lands (USDC 1993, pp. 1-86; Service 1995,
pp. 1-2). Law enforcement agents routinely see butterfly species
protected under the Convention on International Trade in Endangered
Species of Wild Fauna and Flora (CITES) during port inspections in
Florida, often without import declarations or the required CITES
permits (McKissick, Service Law Enforcement, pers. comm. 2011).
In the past, when the Florida leafwing and Bartram's scrub-
hairstreak were widespread on Big Pine Key and throughout southern
Miami-Dade County, collecting likely exerted little pressure on these
butterfly populations. At present, even limited collection from the
small, remaining populations could have deleterious effects on
reproductive and genetic viability and thus could contribute to their
eventual extinction (see Factor E--Effects of Few, Small Populations
and Isolation, below). Collection, which is prohibited on conservation
lands, could occur (e.g., ENP, NKDR, State or County owned lands)
without being detected, because these areas are all not actively
patrolled (see Factor D--The Inadequacy of Existing Regulatory
Mechanisms, below). Similarly, in some areas such as on Big Pine Key,
where numerous pine rockland parcels within NKDR are interspersed among
residential areas, there is no signage indicating that collection is
prohibited (Salvato, pers. comm. 2012). Consequently, the potential for
collection of eggs, larvae, pupae, and adult butterflies exists, and
such collection could go undetected, despite the protection provided on
Federal or other public lands.
We have direct evidence of interest in the collecting, as well as
proposed commercial sale, of the Florida leafwing and Bartram's scrub-
hairstreak. Salvato (pers. comm. 2011) has also been contacted by
several individuals requesting specimens of the Florida leafwing, as
well as information regarding locations where both butterflies may be
collected in the field. Salvato (pers. comm. 2012) observed several
individuals collecting butterflies at Navy Wells during 2005, including
times when Bartram's scrub-hairstreak was present at this site.
We are also aware of multiple Web sites that offer or have offered
specimens of south Florida butterflies for sale that are candidates for
listing under the Act (Minno, pers. comm. 2009; Nagano, pers. comm.
2011; Olle, pers. comm. 2011). Until recently, one Web site offered
male and female Florida leafwing specimens for [euro]110.00 and
[euro]60.00 (euros), respectively (approximately $144 and $78). It is
unclear from where the specimens originated or when they were
collected, but this butterfly is now mainly restricted to ENP where
collection is prohibited. The same Web site currently offers specimens
of Bartram's scrub-hairstreak for [euro]10.00 ($13). It is unclear from
where these specimens originated or when they were collected. The
hairstreak can be found on private lands on Big Pine Key and perhaps
locally within Miami-Dade County. However, given that the majority of
known populations of both butterflies now
[[Page 49892]]
occur within protected Federal, State, and County lands, it is highly
likely that some specimens are being poached.
Scientific Research
Some techniques (e.g., capture, handling) used to understand or
monitor the leafwing and hairstreak butterflies have the potential to
cause harm to individuals or habitat. Visual surveys, transect counts,
and netting for identification purposes have been performed during
scientific research and conservation efforts with the potential to
disturb or injure individuals or damage habitat. Mark-recapture, a
common method used to determine population size, has been used by some
researchers to monitor Florida leafwing and Bartram's scrub-hairstreak
populations (Emmel et al. 1995, p. 4; Salvato 1999, p. 24). This method
has received some criticism. While mark-recapture may be preferable to
other sampling estimates (e.g., count-based transects) in obtaining
demographic data when used in a proper design on appropriate species,
such techniques may also result in deleterious impacts to captured
butterflies (Mallet et al. 1987, pp. 377-386; Murphy 1988, pp. 236-239;
Haddad et al. 2008, pp. 929-940).
Although effects may vary depending upon taxon, technique, or other
factors, some studies suggest that marking may damage (wing damage) or
kill butterflies or alter their behaviors (Mallet et al. 1987, pp. 377-
386; Murphy 1988, pp. 236-239). Salvato (pers. comm. 2012) ceased using
mark-recapture shortly after initiating his long-term leafwing studies
when he realized how much the tagging altered from the butterflies'
cryptic (camouflage) underside as individuals alit (rested) on pineland
foliage. Murphy (1988, p. 236) and Mattoni et al. (2001, p. 198)
indicated that studies on various lycaenids (small butterflies known as
hairstreaks and blues) have demonstrated mortality and altered behavior
as a result of marking. Conversely, other studies have found that
marking did not harm individual butterflies or populations (Gall 1984,
pp. 139-154; Orive and Baughman 1989, p. 246; Haddad et al. 2008, p.
938). Emmel et al. (1995, p. 4) conducted mark-recapture studies on the
hairstreak and noted no detrimental effects. In addition several
individuals were re-encountered (recaptured) during the days following
marking. However, researchers currently studying the populations of the
endangered Miami blue in the Florida Keys have opted not to use mark-
release-recapture techniques due to the potential for damage to this
small, fragile lycaenid (Haddad and Wilson 2011, p. 3).
Summary of Factor B
Collection interest of imperiled butterflies is high, and there are
ample examples of collection pressure contributing to extirpations.
Although we do not have information indicating the extent to which the
Florida leafwing and Bartram's scrub-hairstreak are being collected, we
have evidence of both being recently offered for sale. Even limited
collection from the remaining metapopulations could have deleterious
effects on reproductive and genetic viability of both butterflies and
could contribute to their extinction. Although the effects of various
scientific studies on butterflies vary amongst species, we do have
limited information to suggest that techniques such as mark-recapture
may have deleterious impacts to the Florida leafwing and Bartram's
scrub-hairstreak. We consider collection, including for scientific
research, to be a significant threat to both butterflies due to the few
remaining metapopulations, reduced population sizes, restricted range,
and because collection could potentially occur at any time.
Factor C. Disease or Predation
Florida Leafwing
A number of predators have been documented to impact Florida
leafwings throughout their life cycle. One of the earliest natural
history accounts of the leafwing (Matteson 1930, p. 8) reported ants as
predators of leafwing eggs in Miami. On Big Pine Key, Hennessey and
Habeck (1991, p. 17) encountered a pupa of the Florida leafwing being
consumed by ants. Land (pers. comm. 2009) observed a native twig ant
(Pseudomyrmex pallidus) carrying a young leafwing larva in Long Pine
Key. Salvato and Salvato (2012, p. 3) witnessed an older leafwing larva
repelling P. pallidus attacks while attempting to pupate. Minno (pers.
comm. 2009) noted that the larger nonnative graceful twig ant
(Pseudomyrmex gracilis) is also known to consume immature butterflies
and moths. Salvato and Salvato (2012, p. 3) have observed a graceful
twig ant attempting to capture a young leafwing larva. Cannon (2006,
pp. 7-8) reported high mortality of giant and Bahamian (P. a.
andraemon) swallowtail eggs from a nonnative species of twig ant
(Pseudomyrmex spp.) on Big Pine Key, within habitat formerly occupied
by the Florida leafwing. Both native and nonnative Pseudomyrmex ants
are abundant within Long Pine Key and are frequently encountered
patrolling the racemes of pineland croton. Forys et al. (2001, p. 257)
found high mortality among immature giant swallowtails (Papilio
cresphontes) from imported red fire ant (Solenopsis invicta) predation
in experimental trials and suggested other butterflies in southern
Florida might also be influenced.
Additional predators of immature Florida leafwings include spiders
(Rutkowski 1971, p. 137; Glassberg et al. 2000, p. 99; Salvato and
Salvato 2010e, p. 6; 2011a, p. 103; 2012c, p. 3), ambush bugs (Salvato
and Salvato 2008, p. 324), and possibly mites (Salvato and Salvato
2010e, p. 6). Salvato and Salvato (unpublished data) have examined the
bite marks on wings of numerous adults in the field suggesting a
variety of birds and lizards are among the predators of this butterfly.
A number of parasites have been documented to impact Florida
leafwings throughout their life cycle. Hennessey and Habeck (1991, p.
16) and Salvato and Hennessey (2004, p. 247) noted that leafwing egg
mortality within ENP and Big Pine Key, from trichogrammid wasp
(Trichogramma sp. near (nr) pretiosum) parasitism, ranged from 70 to
100 percent. Salvato and Salvato (2011b, p. 2) continually encounter
leafwing eggs that have been attacked by Trichogramma sp. nr pretiosum,
suggesting this wasp remains a consistent parasitoid for the leafwing
within ENP.
Caldas (1996, p. 89), Muyshondt (1974, pp. 306-314), DeVries (1987,
p. 21) and Salvato and Hennessey (2003, p. 247) each indicated high
parasitism rates from tachinid flies for larvae of Anaea or similar
genera. Hennessey and Habeck (1991, p. 17) and Salvato et al. (2009, p.
101) each encountered Florida leafwing larvae within ENP that had been
parasitized by Chetogena scutellaris (Diptera: Tachinidae). Ongoing
studies of leafwing larvae in Long Pine Key have indicated that C.
scutellaris serves as a consistent mortality factor to the butterfly in
this part of its range (Salvato et al. 2009, p. 101; Salvato and
Salvato 2010a, p. 95). Current studies suggest that leafwing mortality
from the fly can vary considerably from year to year, thereby also
influencing overall population numbers of the butterfly. In 2011,
nearly all leafwing larvae observed to be parasitized by C.
scutellaris, died prior to pupation. Conversely, in winter of 2012,
three of four leafwing larvae observed to be heavily parasitized by the
fly were found to successfully pupate and emerge (Salvato and Salvato
2012, p. 3).
Salvato et al. (2008, p. 237) observed a biting-midge, Forcipomyia
(Microhelea) fuliginosa (Diptera: Ceratopogonidae), feeding on a young
Florida leafwing larva within ENP.
[[Page 49893]]
Ongoing studies of F. (M.) fuliginosa and a second biting midge F. (M.)
eriophora (Salvato et al. 2012, p. 232) indicate they consistently
parasitize leafwing larvae within Long Pine Key throughout their
development.
Salvato and Salvato (2012, p. 1) have monitored Florida leafwing
immature development in the field for several years at Long Pine Key.
To date these studies have measured mortality rates of more than 70
percent for immature leafwing, individuals dying from various
parasites, predators, and other factors such as fungal pathogens
(Salvato and Salvato 2012, p. 1). The majority of mortality noted thus
far in these studies has occurred in the earliest, immature stages.
Bartram's Scrub-Hairstreak
Native parasites and predators have been documented to impact
Bartram's scrub-hairstreaks. Hennessey and Habeck (1991, p. 19)
collected an older hairstreak larva on Big Pine Key from which a single
braconid wasp emerged during pupation. During 2010, Salvato et al.
(2012, p. 113) encountered a hairstreak larva within Long Pine Key that
had been parasitized by C. scutellaris. These are the only known
records for a larval parasitoid on this butterfly. Tracking the fate of
hairstreak pupae is extremely difficult because they pupate in the
ground litter (Worth et al. 1996, p. 63). Collection of other
parasitized hairstreak larvae is needed to determine the influence of
parasitism on its early stages (Salvato and Hennessey 2004, p. 225).
Salvato and Salvato (2010d, p. 71) observed erythraeid larval mite
parasites on an adult Bartram's scrub-hairstreak in Long Pine Key.
Although mite predation on butterflies is rarely fatal (Treat 1975, pp.
1-362), the role of parasitism by mites in the natural history of the
hairstreak requires further study. Salvato and Salvato (2008, p. 324)
have observed dragonflies (Odonata) preying on adult hairstreaks. Crab
spiders, orb weavers, ants, and number of other predators discussed as
mortality factors for the leafwing have also been frequently observed
on croton during hairstreak surveys and may also prey on hairstreak
adults and larvae (Salvato and Hennessey 2004, p. 225; Salvato, pers.
comm. 2012). NKDR biologists have witnessed nonnative Cuban anoles
(Anolis equestris) attempting to prey on adult Bartram's scrub-
hairstreaks (C. Anderson, pers. comm. 2013). Minno and Minno (2009, p.
72) also cite nonnative predators such as ants as a major threat to
both butterflies.
Summary of Factor C
At this time, it is not known to what extent predation, parasitism,
or disease may act as threats to the Florida leafwing and Bartram's
scrub-hairstreak. Studies have documented a wide array of predators and
parasitoids and, in some cases, high levels of mortality amongst
immature leafwings, throughout development. Although many of the
mortality factors of immature leafwing have also been shown to
influence the hairstreak, to date, these studies have been limited.
Disease, in the form of viruses or fungal pathogens, is known to cause
mortality of the young leafwing larvae; these factors may also
influence the young hairstreak larvae. Given the leafwing and
hairstreak butterflies' low numbers and few occurrences, and limited
distributions, it is unclear how the leafwing and hairstreak will
respond to these factors.
D. The Inadequacy of Existing Regulatory Mechanisms
Under this factor, we examine whether existing regulatory
mechanisms are inadequate to address the threats to the species
discussed under the other factors. Section 4(b)(1)(A) of the Act
requires the Service to take into account ``those efforts, if any,
being made by any State or foreign nation, or any political subdivision
of a State or foreign nation, to protect such species. . . .'' In
relation to Factor D, we interpret this language to require the Service
to consider relevant Federal, State, and Tribal laws, plans,
regulations, and other such mechanisms that may minimize any of the
threats we describe in threat analyses under the other four factors, or
otherwise enhance conservation of the species. We give strongest weight
to statutes and their implementing regulations and to management
direction that stems from those laws and regulations. An example would
be State governmental actions enforced under a State statute or
constitution, or Federal action under statute.
Having evaluated the significance of the threat as mitigated by any
such conservation efforts, we analyze under Factor D the extent to
which existing regulatory mechanisms are inadequate to address the
specific threats to the species. Regulatory mechanisms, if they exist,
may reduce or eliminate the impacts from one or more identified
threats. In this section, we review existing State and Federal
regulatory mechanisms to determine whether they effectively reduce or
remove threats to the Florida leafwing and Bartram's scrub-hairstreak
butterflies.
Existing regulatory mechanisms that could provide some protection
for the Florida leafwing and Bartram's scrub-hairstreak butterflies
include: (1) the National Park Service Organic Act and its implementing
regulations; (2) the National Wildlife Refuge System Administration Act
(16 U.S.C. 668dd-ee) as amended, and the Refuge Recreation Act (16
U.S.C. 460k-460k-4) and their implementing regulations.
Federal
National Park Service (NPS) regulations at 36 CFR 2.1 and 2.2
prohibit visitors from harming or removing wildlife, listed or
otherwise, from ENP. In addition, NPS regulation 36 CFR 2.5 prohibits
visitors from conducting research or collecting specimens without a
permit. Although ENP was not able to provide specific information
concerning poaching of butterflies or enforcement of NPS regulations
protecting the butterflies and their habitats from harm the apparent
online sales of the butterflies suggests that poaching could be
occurring. Insufficient implementation or enforcement could become a
threat to the two butterflies in the future if they continue to decline
in numbers.
Special Use Permits (SUPs) are issued by the Refuges as authorized
by the National Wildlife Refuge System Administration Act (16 U.S.C.
668dd-ee) as amended, and the Refuge Recreation Act. The Service's
South Florida Ecological Services Office and NKDR coordinate annually
on potential impacts to the Florida leafwing and Bartram's scrub-
hairstreak prior to issuance of a SUP to the FKMCD (see Factor E--
Pesticides, below). In addition, as discussed above (Factor A--
Conservation Efforts to Reduce the Present or Threatened Destruction,
Modification, or Curtailment of Its Habitat or Range), the CCP for the
Lower Key Refuges provides specifically for maintaining and restoring
butterfly populations within NKDR, including the Bartram's scrub-
hairstreak and Florida leafwing butterflies.
State
The Florida leafwing and Bartram' scrub-hairstreak butterflies are
not currently listed by the State of Florida ESA, so there are no
existing regulations designated to protect them.
Local
Under Miami-Dade County ordinance (Section 26-1), a permit is
required to conduct scientific research (Rule 9) on county
environmental lands. In
[[Page 49894]]
addition, Rule 8 of this ordinance provides for the preservation of
habitat within County parks or areas operated by the Parks and
Recreation Department. We have no information to suggest that other
counties within the range of the leafwing and hairstreak have
regulatory mechanisms that provide any protections for these
butterflies.
Summary of Factor D
In summary, existing regulatory mechanisms that help conserve the
Florida leafwing and Bartram's scrub-hairstreak are present on Federal
lands (ENP and NKDR) and within Miami-Dade County conservation areas.
The butterflies are provided limited or no protections on State of
Florida or Monroe County lands. Despite the existing regulatory
mechanisms, habitat loss and modification, inconsistent fire
management, poaching, and pesticide applications suggest that existing
regulatory mechanisms have not been sufficient to provide for the
conservation of either species.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Effects of Few, Small Populations and Isolation
The Florida leafwing and Bartram's scrub-hairstreak are vulnerable
to extinction due to their severely reduced range, reduced population
size, lack of metapopulation structure, few remaining populations, and
relative isolation. Abundance of the Florida leafwing and Bartram's
scrub-hairstreak is not known, but each butterfly is estimated to
number in the hundreds, and at times, possibly much lower. Although
highly dependent on individual species considered, a population of
1,000 has been suggested as marginally viable for an insect
(Schweitzer, TNC, pers. comm. 2003). Schweitzer (pers. comm. 2003) has
also suggested that butterfly populations of less than 200 adults per
generation would have difficulty surviving over the long term. In
comparison, in a review of 27 recovery plans for listed insect species,
Schultz and Hammond (2003, p. 1377) found that 25 plans broadly
specified metapopulation features in terms of requiring that recovery
include multiple population areas (the average number of sites required
was 8.2). The three plans that quantified minimum population sizes as
part of their recovery criteria for butterflies ranged from 200 adults
per site (Oregon silverspot (Speyeria zerene hippolyta)) to 100,000
adults (Bay checkerspot (Euphydryas editha bayensis)) (Schulz and
Hammond 2003, pp. 1374-1375).
Schultz and Hammond (2003, pp. 1372-1385) used population viability
analyses to develop quantitative recovery criteria for insects whose
population sizes can be estimated and applied this framework in the
context of the Fender's blue (Icaricia icarioides fenderi), a butterfly
listed as endangered in 2000 due to the threats on the remaining
reduced population and limited remaining habitat. They found the
Fender's blue to be at high risk of extinction due to agriculture
practices, development activities, forestry practices, grazing,
roadside maintenance, and commercial Christmas tree farming.
Losses in diversity within populations of the Florida leafwing and
Bartram's scrub-hairstreak may have already occurred (Salvato, pers.
comm. 2012). The leafwing and hairstreak have been extirpated from
several locations where they were previously recorded (Baggett 1982,
pp. 78-81; Salvato and Hennessey 2003, p. 243; 2004 p. 223). Initially
described from Brickell Hammock in Coral Gables, Florida (present day
Vizcaya Museum and Gardens), in the 1940s (Salvato, pers. comm. 2012),
mainland populations of the leafwing have subsequently retreated with
the loss, fragmentation and degradation of native pine rocklands
throughout Miami-Dade County (Baggett 1982, pp. 78-81; Salvato and
Hennessey 2003, p. 243). At present, the leafwing is extant only within
ENP, and ongoing surveys suggest the butterfly actively disperses
throughout the Long Pine Key region of the Park (Salvato and Salvato
2010, p. 91; 2010c, p. 139). Once locally common at Navy Wells and the
Richmond Pine Rocklands (which occur approximately 8 and 27 km (5 and
17 mi) to the northeast of ENP, respectively), leafwings are not known
to have bred at either location in more than 25 years (Salvato and
Hennessey 2003, p. 243; Salvato pers. comm. 2012). In the lower Florida
Keys, the leafwing had maintained a stronghold for many decades on Big
Pine Key, within NKDR, until 2006 when that population disappeared due
to a variety of factors (Salvato and Salvato 2010c, pp. 139-140).
The Bartram's scrub-hairstreak is extant within ENP, Navy Wells,
Camp Owaissa Bauer, Richmond Pine Rocklands, as well as on Big Pine Key
(Baggett 1982, pp. 80-81; Smith et al. 1994, pp. 118-119; Salvato and
Salvato 2010b, p. 154). However, given the limited dispersal abilities
of this butterfly, the distance between these sites, (Worth et al.
1996, p. 63; Salvato and Hennessey, p 223) and their fragmentation, it
is unlikely there is any genetic exchange between locations.
Another south Florida lycaenid, the Miami blue (Cyclargus thomasi
bethunebakeri), also appears to have been impacted by relative
isolation similar to that of the hairstreak. Over the past decade, this
blue butterfly was known from only two contemporary populations, Bahia
Honda Key and Key West National Wildlife Refuge. Saarinen (2009, p. 79)
suggested that the separation of genetic exchange between these extant
populations was only recent (within the past few decades). Despite
fluctuations in annual and seasonal population sizes, the Bahia Honda
blue population was thought to have retained an adequate amount of
genetic diversity to maintain the butterfly. However, as of 2010, the
Miami blue population on the island was extirpated.
Extant hairstreak populations are likely experiencing a similar
lack of continuity in genetic exchange given their current fragmented
distribution. Based upon modeling with a different butterfly species,
Fleishman et al. (2002, pp. 706-716) argued that factors such as
habitat quality may influence metapopulation dynamics, driving
extinction and colonization processes, especially in systems that
experience substantial natural and anthropogenic environmental
variability (see Environmental Stochasticity below). If only one or a
few metapopulations remain, it is absolutely critical that remaining
genetic diversity and gene flow are retained. Conservation decisions to
augment or reintroduce populations should not be made without careful
consideration of habitat availability, genetic adaptability, the
potential for the introduction of maladapted genotypes, and other
factors (Frankham 2008, pp. 325-333; Saarinen et al. 2009, p. 36; See
Factors A-D above).
In general, isolation, whether caused by geographic distance,
ecological factors, or reproductive strategy, will likely prevent the
influx of new genetic material and can result in a highly inbred
population with low viability or fecundity (Chesser 1983, p. 68).
Natural fluctuations in rainfall, hostplant vigor, or predation may
weaken a population to such an extent that recovery to a viable level
would be impossible. Isolation of habitat can prevent recolonization
from other sites and result in extinction. The leafwing and hairstreak
are restricted to one (leafwing) or a few small (hairstreak) localized
populations. The extent of
[[Page 49895]]
habitat fragmentation makes these butterflies vulnerable to extinction.
Environmental Stochasticity
The climate of southern Florida and the Florida Keys is driven by a
combination of local, regional, and global events, regimes, and
oscillations. There are three main ``seasons'': (1) The wet season,
which is hot, rainy, and humid from June through October, (2) the
official hurricane season that extends 1 month beyond the wet season
(June 1 through November 30) with peak season being August and
September, and (3) the dry season, which is drier and cooler from
November through May. In the dry season, periodic surges of cool and
dry continental air masses influence the weather with short-duration
rain events followed by long periods of dry weather.
According to the Florida Climate Center, Florida is by far the most
vulnerable State in the United States to hurricanes and tropical storms
(http://coaps.fsu.edu/climate_center/tropicalweather.shtml). Based on
data gathered from 1856 to 2008, Klotzbach and Gray (2009, p. 28)
calculated the climatological and current-year probabilities for each
State being impacted by a hurricane and major hurricane. Of the coastal
States analyzed, Florida had the highest climatological probabilities,
with a 51 percent probability of a hurricane and a 21 percent
probability of a major hurricane over a 52-year time span. Florida had
a 45 percent current-year probability of a hurricane and an 18 percent
current-year probability of a major hurricane (Klotzbach and Gray 2009,
p. 28). Given the Florida leafwing and Bartram's scrub-hairstreaks' low
population sizes and few isolated occurrences within locations prone to
storm influences, these butterflies are at substantial risk from
hurricanes, storm surges, or other extreme weather. Depending on the
location and intensity of a hurricane or other severe weather event, it
is possible that the leafwing and hairstreak could become locally
extirpated or extinct as a result of one event.
Other processes to be affected by climate change include
temperatures, rainfall (amount, seasonal timing, and distribution), and
storms (frequency and intensity). Temperatures are projected to rise
from 2 [deg]C to 5 [deg]C (3.6 [deg]F to 9 [deg]F) for North America by
the end of this century (IPCC 2007, pp. 7-9, 13). Based upon modeling,
Atlantic hurricane and tropical storm frequencies are expected to
decrease (Knutson et al. 2008, pp. 1-21). By 2100, there should be a 10
to 30 percent decrease in hurricane frequency with a 5 to 10 percent
wind increase. This is due to more hurricane energy available for
intense hurricanes. However, hurricane frequency is expected to drop
because more wind shear will impede initial hurricane development. In
addition to climate change, weather variables are extremely influenced
by other natural cycles, such as El Ni[ntilde]o Southern Oscillation
with a frequency of every 4 to 7 years, solar cycle (every 11 years),
and the Atlantic Multi-decadal Oscillation. All of these cycles
influence changes in Floridian weather. The exact magnitude, direction,
and distribution of all of these changes at the regional level are
difficult to project.
The Florida leafwing and Bartram's scrub-hairstreak have adapted
over time to the influence of tropical storms and other forms of
adverse weather conditions (Minno and Emmel 1994, p. 671; Salvato and
Salvato 2007, p. 154). However, given the substantial reduction in the
historic range of these butterflies in the past 50 years, the threat
and impact of tropical storms and hurricanes on their remaining
populations is much greater than when their distribution was more
widespread (Salvato and Salvato 2010a, p. 96; 2010b, p. 157; 2010c, p.
139).
During late October 2005, Hurricane Wilma caused substantial damage
to the pine rocklands of northwestern Big Pine Key (Salvato and Salvato
2010c, p. 139), specifically within the Watson Hammock region of NKDR,
the historic stronghold for the Florida leafwing on the island. In
historical instances when leafwing and hairstreak population numbers
were larger on Big Pine, such as following Hurricane Georges in 1998,
these butterflies appeared able to recover soon after a storm (Salvato
and Salvato 2010c, p. 139). In ENP, where leafwing and hairstreak
densities remained stable, these butterflies were minimally affected by
the 2005 hurricane season (Salvato and Salvato 2010a, p. 96, 2010b, p.
157). However, for the leafwing, given its substantial decline on Big
Pine Key prior to Wilma, it is possible that the impact of this storm
served to further hinder and reduce extant populations of the butterfly
on the island (Salvato and Salvato 2010c, p. 139).
Environmental factors have likely impacted both butterflies and
their habitat within their historical and current ranges. For example,
unusually cold temperatures were encountered throughout southern
Florida during the winters of 2009 and 2010. Sadle (pers. comm. 2009)
noted frost damage on croton at ENP on Long Pine Key in late 2009, but
observed living larvae earlier that year, when temperatures were at or
barely above freezing (2.2 [deg]C; 36 [deg]F) and frost was on the
ground. Frost in winter 2010 resulted in substantial dieback of native
plants, including damage and widespread defoliation of the croton in
Long Pine Key (Sadle, pers. comm. 2010; Land, pers. comm. 2010; Hallac
et al. 2010, pp. 2-3). Fifty percent of the individual leafwing larvae
were impacted by the cold and observed to be dead or without nearby
food supplies within Long Pine Key (Hallac et al. 2010, p. 3). Although
Salvato and Salvato (2011, p. 2) did not record increased butterfly
larval mortality on their survey sites in ENP during early 2010, they
did encounter larvae on frost-killed plants and indicated those larvae
unable to successfully reach healthier adjacent hostplants likely
perished.
During late 2010, Salvato and Salvato (2011, p. 2) noted increased
larval leafwing mortality on their survey sites due to a number of
factors, including cold. Sadle (pers. comm. 2011) also observed
significant leaf and stem damage to croton during the same time period.
A single dead leafwing larva was observed on a frost-damaged croton
plant, though it is unclear if the mortality was a direct or indirect
consequence of the freezing temperatures (Sadle, pers. comm. 2011).
Salvato and Salvato (2011, p. 2) examined several (n = 4) dark,
apparently frozen leafwing larvae during this time period, but later
determined these had likely been killed from tachinid fly parasitism
prior to the freeze. Sadle (pers. comm. 2011) and Salvato and Salvato
(2011, p. 2) noted living larvae following the late 2010 freeze,
largely in areas unaffected by the frost. From these observations,
Sadle (pers. comm. 2011) suggested that frost damage may produce
similar effects to loss of aboveground plant parts that results from
fire. It is not clear what the short- or long-term impacts of prolonged
cold periods may be on leafwing or hairstreak populations; however, it
is likely that prolonged cold periods have some negative impacts on
both the butterflies and their hostplant (Sadle, pers. comm. 2010;
Land, pers. comm. 2010).
As described above (see Factor C), ongoing natural history studies
by Salvato and Salvato (2012c, p. 1) indicate that the extant leafwing
population within Long Pine Key experiences up to 80 percent mortality
amongst immature larval stages. A similarly high mortality has been
noted for the endangered Schaus swallowtail in southern Florida (Emmel
1997, p. 11). Such high levels of mortality may explain why leafwing
population
[[Page 49896]]
densities vary considerably from year to year. As with the influence of
tropical storms, population-level recoveries from high rates of
parasitism or other factors at a select location would historically be
offset from less-affected adjacent populations. Opportunities for such
population-level recovery are now severely restricted (see ``Effects of
Few, Small Populations and Isolation'' in this section).
Pesticides
Efforts to control mosquitoes and other insect pests have increased
as human activity and population have increased in south Florida. To
control mosquito populations, organophosphate (naled) and pyrethroid
(permethrin) adulticides are applied by mosquito control districts
throughout south Florida. In a rare case in upper Key Largo, another
organophosphate (malathion) was applied in 2011 when the number of
permethrin applications reached its annual limit. All three of these
compounds have been characterized as being highly toxic to nontarget
insects by the U.S. Environmental Protection Agency (2002, p. 32;
2006a, p. 58; 2006b, p. 44). The use of such pesticides (applied using
both aerial and ground-based methods) for mosquito control presents a
potential risk to nontarget species, such as the Florida leafwing and
Bartram's scrub-hairstreak.
The potential for mosquito control chemicals to drift into
nontarget areas and persist for varying periods of time has been
documented. Hennessey and Habeck (1989, pp. 1-22; 1991, pp. 1-68) and
Hennessey et al. (1992, pp. 715-721) illustrated the presence of
mosquito spray residues long after application in habitat of the
federally endangered Schaus swallowtail (Papilio aristodemus
ponceanus),), as well as the Florida leafwing, Bartram's scrub-
hairstreak, and other imperiled species in both the upper (Crocodile
Lake NWR, North Key Largo) and lower Keys (NKDR). Residues of aerially
applied naled were found 6 hours after application in a pineland area
that was 750 meters (820 yards) from the target area; residues of
fenthion (an adulticide no longer used in the Keys) applied via truck
were found up to 50 meters (55 yards) downwind in a hammock area 15
minutes after application in adjacent target areas (Hennessey et al.
1992, pp. 715-721).
More recently, Pierce (2009, pp. 1-17) monitored naled and
permethrin deposition following application in and around NKDR from
2007 to 2009. Permethrin, applied by truck, was found to drift
considerable distances from target areas with residues that persisted
for weeks. Naled, applied by plane, was also found to drift into
nontarget areas but was much less persistent, exhibiting a half-life of
approximately 6 hours. To expand this work, Pierce (2011, pp. 6-11)
conducted an additional deposition study in 2010 focusing on permethrin
drift from truck spraying and again documented low but measurable
amounts of permethrin in nontarget areas. In 2009, Bargar (pers. comm.
2011) conducted two field trials on NKDR that detected significant
naled residues at locations within nontarget areas on the Refuge that
were up to 402 meters (440 yards) from the edge of zones targeted for
aerial applications. After this discovery, the Florida Key Mosquito
Control District recalibrated the on-board model
(Wingman(copyright)). Naled deposition was reduced in some
of the nontarget zones following recalibration (Bargar 2012b, p. 3).
In addition to mosquito control chemicals entering nontarget areas,
the toxic effects of mosquito control chemicals to nontarget organisms
have also been documented. Lethal effects on nontarget moths and
butterflies have been attributed to fenthion and naled in both south
Florida and the Florida Keys (Emmel 1991, pp. 12-13; Eliazar and Emmel
1991, pp. 18-19; Eliazar 1992, pp. 29-30). Zhong et al. (2010, pp.
1961-1972) investigated the impact of single aerial applications of
naled on the endangered Miami blue butterfly larvae in the field.
Survival of butterfly larvae in the target zone was 73.9 percent, which
was significantly lower than in both the drift zone (90.6 percent) and
the reference (control) zone (100 percent), indicating that direct
exposure to naled poses significant risk to Miami blue larvae. Fifty
percent of the samples in the drift zone also exhibited detectable
concentrations, once again exhibiting the potential for mosquito
control chemicals to drift into nontarget areas. Bargar (pers. comm.
2011) observed cholinesterase activity depression, to a level shown to
cause mortality in the laboratory, in great southern white and Gulf
fritillary butterflies exposed to naled during an application on NKDR
in both target and nontarget zones.
In the lower Keys, Salvato (2001, pp. 8-14) suggested that declines
in populations of the Florida leafwing were also partly attributable to
mosquito control chemical applications. Salvato (2001, p. 14; 2002, pp.
56-57) found relative populations of the Florida leafwing, when extant
on Big Pine Key within NKDR, to increase during drier years when
adulticide applications over the pinelands decreased, although
Bartram's scrub-hairstreak did not follow this pattern. Salvato (2001,
p. 14) suggested that butterflies, such as the leafwing, were
particularly vulnerable to aerial applications based on their tendency
to roost within the pineland canopy, an area with maximal exposure to
aerial treatments. Because roosting sites for the Bartram's hairstreak
are not well documented, more study is needed to assess their potential
exposure. The role of vegetation in limiting exposure is unknown, but
could be important when considering that spraying operations are
conducted during early morning and late evening hours when, presumably,
nontarget butterflies would be occupying roost sites (C. Anderson,
pers. comm. 2013).
Toxicity data on Florida native butterflies exposed to permethrin
and naled in the laboratory (Hoang et al. 2011, pp. 997-1005) were used
to calculate hazard quotients (concentrations in the environment--
concentrations causing an adverse effect) in order to assess the risk
that concentrations of naled and permethrin found in the field pose to
butterflies. A hazard quotient where the environmental concentration is
greater than the concentration known to cause an adverse effect
(mortality in this case), indicates significant risk to the organism.
Environmental exposures for naled and permethrin were taken from Zhong
et al. (2010, pp. 1961-1972) and Pierce (2009, pp. 1-17), respectively,
and represent the highest concentrations of each chemical that were
quantified during field studies in the Florida Keys. When using the
lowest median lethal concentrations from the laboratory study, the
hazard quotients for permethrin and naled indicated potential acute
hazards to butterflies. Bargar (2012a, pp. 5-6) also conducted a
probabilistic risk assessment using naled deposition values from NKDR
and estimated that field-measured naled concentrations did pose a risk
to adult butterflies of some species, particularly for species with
large surface area to weight ratios.
Based on these studies, it can be concluded that mosquito control
activities that involve the use of both aerial and ground-based
spraying methods have the potential to deliver pesticides in quantities
sufficient to cause adverse effects to nontarget species in both target
and nontarget areas. It should be noted that many of the studies
referenced above dealt with single application scenarios and examined
effects on only one to two butterfly life stages. Under a realistic
scenario, the potential exists for exposure to all life stages to occur
over
[[Page 49897]]
multiple applications in a season. In the case of a persistent compound
like permethrin where residues remain on vegetation for weeks, the
potential exists for nontarget species to be exposed to multiple
pesticides within a season (e.g., permethrin on vegetation coupled with
aerial exposure to naled).
Spraying practices by the Florida Keys Mosquito Control District
(FKMCD) at NKDR have changed to reduce pesticide use over the years. In
addition, larvicide treatments to surrounding islands have
significantly reduced adulticide use on Big Pine Key, No Name Key, and
the Torch Keys since 2003 (FKMCD 2012, p. 11). According to the Special
Use Permit issued by the Service, the number of aerially applied naled
treatments allowed on NKDR has been limited since 2008 (FKMCD 2012, pp.
10-11).
The Service's Integrated Pest Management (IPM) Policy (569 FW 1)
establishes procedures and responsibilities for pest management
activities on and off Service lands. These may include (1) Preparing
pesticide use proposals (PUPs) for approval before applying pesticides;
(2) entering pesticide usage information annually into the online IPM
and Pesticide Use Proposal System (PUPS) database; (3) conducting
Endangered Species Act consultations; and (4) following National
Environmental Protection Act policies. Since these butterflies have
been on the candidate list, the Service's South Florida Ecological
Services Office and NKDR coordinate annually on potential impacts to
the Florida leafwing and Bartram's scrub-hairstreak prior to issuance
of a PUP to the FKMCD. Based on this consultation, 478 ha (1,180 ac)
(705 ha (1,741 ac) of pine rockland) in the NKDR have been designated
no-spray zones by agreement (as of May 2012) between the Service and
FKMCD that includes the core habitat used by pine rockland butterflies
(C. Anderson, pers. comm. 2012a; Service 2012, p. 32). In addition,
several linear miles of pine rockland habitat within the Refuge-
neighborhood interface were excluded from truck spray applications in
the most sensitive habitats. These exclusions and buffer zones
encompass over 95 percent of extant croton distribution on Big Pine
Key, and include the majority of known extant and historical Florida
leafwing and Bartram's scrub-hairstreak population centers on the
island (Salvato, pers. comm. 2012). However, some areas of pine
rocklands within NKDR are still sprayed with naled (aerially applied
adulticide), and buffer zones remain at risk from drift; additionally,
private residential areas and roadsides across Big Pine Key are treated
with permethrin (ground-based applied adulticide) (Salvato 2001, p.
10). Therefore, the hairstreak and, if extant, the leafwing and their
habitat on Big Pine Key may be directly or indirectly (via drift)
exposed to adulticides used for mosquito control at some unknown level.
Although there is evidence that mosquito control practices may
influence butterfly species, limited information currently exists about
population-level impacts. Actual impacts to the Florida leafwing and
Bartram's scrub-hairstreak from mosquito control are unknown at this
time; however, additional research is under way to quantify risk.
The Service will ensure compliance with our Pest Management Policy
and the Act. We anticipate the need to expand existing buffer and no
spray zones to include all hostplant-containing areas on the NKDR, as
well as implement other measures (e.g., use more larvicides and less
adulticides) to prevent adverse impacts to the butterflies and their
habitat (on and off NKDR). Any changes to the pesticide application
protocol will be closely coordinated with FKMCD. In addition, field
monitoring may be required to demonstrate that application of
pesticides in areas adjacent to Florida leafwing and Bartram's scrub-
hairstreak habitat does not result in drift into the no spray zones, as
has been documented in previous studies.
In general Long Pine Key in ENP does not appear to be regularly
impacted by mosquito control practices, except for the use of
adulticides (e.g., Sumithrin (Anvil)) in Park residential areas and
campgrounds. Housing areas, maintenance areas, outside work areas for
park maintenance staff and contractors, and areas near buildings have
been sprayed in the past (Perry, pers. comm. 2007). Spraying occurred
within ENP following hurricanes in 2005 (Perry, pers. comm. 2008).
Subsequently, however, no spraying has been conducted in or near Long
Pine Key. Populations of these butterflies occurring adjacent to and
outside ENP in suitable and potential habitat within Miami-Dade County
are also vulnerable to the lethal and sublethal effects of adulticide
applications. However, mosquito control pesticide use within Miami-Dade
County pine rockland areas is limited (approximately 2 to 4 times per
year, and only within a portion of proposed critical habitat) (Vasquez,
pers. comm. 2013)
In summary, although substantial progress has been made in reducing
impacts, the potential effects of mosquito control applications and
drift residues remain a threat to both butterflies.
Summary of Factor E
Based on our analysis of the best available information, we have
identified several natural and manmade factors affecting the continued
existence of the Florida leafwing and Bartram's scrub-hairstreak.
Effects of small population size, isolation, and loss of genetic
diversity are likely significant threats. Given the existing few
populations and small size of the populations, environmental
stochasticity may also contribute to imperilment. Other natural (e.g.,
changes to habitat) and anthropogenic factors (e.g., pesticides, fire,
processes affected by climate change) are also identifiable threats.
Cumulative Effects of Threats Under Factor E
The limited distributions and small population sizes of the Florida
leafwing and Bartram's scrub-hairstreak make them extremely susceptible
to habitat loss, degradation, and modification and other anthropogenic
threats. Mechanisms leading to the decline of the Florida leafwing and
Bartram's scrub-hairstreak, as discussed above, range from local (e.g.,
a lack of adequate fire management, fragmentation, poaching), to
regional (e.g., development, pesticides), to global influences (e.g.,
climate change, sea level rise). The synergistic (interaction of two or
more components) effects of threats (such as hurricane effects on a
species with a limited distribution consisting of just a few small
populations) make it difficult to predict population viability. While
these stressors may act in isolation, it is more probable that many
stressors are acting simultaneously (or in combination) on Florida
leafwing and Bartram's scrub-hairstreak populations.
Cumulative Effects: Factors A Through E
Florida Leafwing
The Florida leafwing has been extirpated (no longer in existence)
from nearly 96 percent of its historical range; the only known extant
population occurs within ENP in Miami-Dade County. Threats of habitat
loss and fragmentation, including climatic change (Factor A), poaching
(Factor B), parasitism, predation (Factor C), small population size,
restricted range, and influence of chemical pesticides used for
mosquito control (Factor E), still exist for the only remaining
population.
[[Page 49898]]
Because there is only one small extant population of this butterfly,
and limited law enforcement, collection has and continues to be a
significant threat to this butterfly. Existing regulatory mechanisms
(Factor D) are inadequate to protect this butterfly. The leafwing may
be impacted when pine rocklands are converted to other uses or when
lack of fire causes the conversion to habitats that are unsuitable for
this butterfly. Because the remaining population is isolated and the
butterfly has a limited ability to recolonize historically occupied
habitats that are now highly fragmented, it is vulnerable to natural or
human-caused changes in its habitats. As a result, impacts from
increasing threats, singly or in combination, are likely to result in
the extinction of the butterfly as there is no redundancy of
populations.
Bartram's Scrub-Hairstreak
The Bartram's scrub-hairstreak has been extirpated from nearly 93
percent of its historical range; only five isolated metapopulations
remain on Big Pine Key in Monroe County, Long Pine Key in ENP, and
relict pine rocklands adjacent to the Park in Miami-Dade County. All 5
of these populations are, in part, on protected lands. Threats of
habitat loss and fragmentation from lack of fire (Factor A), poaching
(Factor B), disease, predation (Factor C), small population size,
restricted range, influence of chemical pesticides used for mosquito
control, and sea level rise (Factor E) still exist for the remaining
populations. Because there are only five small populations of the
hairstreak, and limited law enforcement, collection has and continues
to be a significant threat to this butterfly. Existing regulatory
mechanisms (Factor D) are inadequate to protect this butterfly from
poaching. Because populations are isolated and the butterfly has a
limited ability to recolonize historically occupied habitats that are
now highly fragmented, it is vulnerable to natural or human-caused
changes in its habitats. The remaining populations become less
resilient and are not capable of recovering from the threats. As a
result, impacts from increasing threats, singly or in combination, are
likely to result in the extinction of the hairstreak.
Habitat loss, fragmentation, and degradation, and associated
pressures from increased human population are major threats; these
threats are expected to continue, placing these butterflies at greater
risk. Although efforts are being made to conserve natural areas and
apply prescribed fire, the long-term effects of large-scale and wide-
ranging habitat modification, destruction, and curtailment will last
into the future. Based on our analysis of the best available
information, there is no evidence to suggest that vulnerability to
collection and risks associated with scientific or conservation efforts
will change and, instead, are likely to continue into the future. At
this time, we consider predation, parasitism, and disease to be threats
to both butterflies due to their current tenuous statuses. We have no
information to suggest that vulnerability to these threats will change
in the future. Based on our analysis of the best available information,
we find that existing regulatory mechanisms, due to their inherent
limitations and constraints, are inadequate to address threats to these
butterflies throughout their ranges. We have no information to indicate
that poaching, inconsistent fires, pesticide use, or habitat loss will
be ameliorated in the future by enforcement of existing regulatory
mechanisms.
Therefore, we find it reasonably likely that the effects on the
Florida leafwing and Bartram's scrub-hairstreak will continue at
current levels or potentially increase in the future. Effects of small
population size, isolation, and loss of genetic diversity are likely
significant threats as well as natural changes to habitat and
anthropogenic factors (e.g., pesticides, fire, processes affected by
climate change). Collectively, these threats have impacted the
butterflies in the past, are impacting these butterflies now, and will
continue to impact these butterflies in the future.
Determination
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the Florida leafwing and Bartram's scrub-hairstreak butterflies. As
described in detail above, both butterflies are currently at risk
throughout all of their respective ranges due to the immediacy,
severity, and scope of threats from habitat destruction and
modification (Factor A), overutilization (Factor B), disease or
predation (Factor C), inadequacy of existing regulatory mechanisms
(Factor D), and other natural or manmade factors affecting their
continued existence (Factor E). These stressors have had profound
adverse effects on Florida leafwing and Bartram's scrub-hairstreak
populations and the pine rockland habitat. As a result, impacts from
increasing threats, singly or in combination, are likely to result in
the extinction of these butterflies.
The Act defines an endangered species as any species that is ``in
danger of extinction throughout all or a significant portion of its
range'' and a threatened species as any species ``that is likely to
become endangered throughout all or a significant portion of its range
within the foreseeable future.'' We find that the Florida leafwing
butterfly is presently in danger of extinction throughout its entire
range based on the severity and immediacy of threats currently
impacting the subspecies. The overall range has been significantly
reduced; the remaining habitat and population is threatened by a
variety of factors acting in combination to reduce the overall
viability of the subspecies. The risk of extinction is high because the
remaining population is small, isolated, and the potential for
recolonization is limited based on habitat loss and fragmentation,
mosquito control, poaching, parasitism, predation, and climatic change.
The Florida leafwing and Bartram's scrub-hairstreak butterflies are
highly restricted in their ranges and threats occur throughout their
ranges. Therefore, we assessed the status of the species throughout
their entire ranges. The threats to the survival of the species occur
throughout the species' ranges and are not restricted to any particular
significant portion of those ranges. Accordingly, our assessment and
proposed determination applies to both the species throughout their
entire ranges.
Therefore, on the basis of the best available scientific and
commercial information, we propose listing the Bartram's scrub-
hairstreak butterfly as endangered in accordance with sections 3(6) and
4(a)(1) of the Act. We find that a threatened species status is not
appropriate for the Bartram's scrub-hairstreak butterfly because of the
severity and immediacy of the threats, its restricted range (93 percent
loss), threats are occurring rangewide and are not localized, its five
small populations, and because the threats are ongoing and expected to
continue into the future.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness and
conservation by Federal, State, Tribal, and local agencies; private
organizations; and individuals. The Act encourages cooperation with the
States and requires that recovery actions be carried out for all listed
species. The protection required by Federal agencies and the
[[Page 49899]]
prohibitions against certain activities are discussed, in part, below.
The primary purpose of the Act is the conservation of endangered
and threatened species and the ecosystems upon which they depend. The
ultimate goal of such conservation efforts is the recovery of these
listed species, so that they no longer need the protective measures of
the Act. Subsection 4(f) of the Act requires the Service to develop and
implement recovery plans for the conservation of endangered and
threatened species. The recovery planning process involves the
identification of actions that are necessary to halt or reverse the
species' decline by addressing the threats to its survival and
recovery. The goal of this process is to restore listed species to a
point where they are secure, self-sustaining, and functioning
components of their ecosystems.
Recovery planning includes the development of a recovery outline
shortly after a species is listed and preparation of a draft and final
recovery plan. The recovery outline guides the immediate implementation
of urgent recovery actions and describes the process to be used to
develop a recovery plan. Revisions of the plan may be done to address
continuing or new threats to the species, as new substantive
information becomes available. The recovery plan identifies site-
specific management actions that set a trigger for review of the five
factors that control whether a species remains endangered or may be
downlisted or delisted, and methods for monitoring recovery progress.
Recovery plans also establish a framework for agencies to coordinate
their recovery efforts and provide estimates of the cost of
implementing recovery tasks. Recovery teams (comprising species
experts, Federal and State agencies, nongovernmental organizations, and
stakeholders) are often established to develop recovery plans. When
completed, the recovery outline, draft recovery plan, and the final
recovery plan will be available on our Web site (http://www.fws.gov/endangered), or from our South Florida Ecological Services Field Office
(see FOR FURTHER INFORMATION CONTACT).
Implementation of recovery actions generally requires the
participation of a broad range of partners, including other Federal
agencies, States, Tribes, nongovernmental organizations, businesses,
and private landowners. Examples of recovery actions include habitat
restoration (e.g., restoration of native vegetation), research, captive
propagation and reintroduction, and outreach and education. The
recovery of many listed species cannot be accomplished solely on
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires
cooperative conservation efforts on private, State, and Tribal lands.
If these butterflies are listed, funding for recovery actions will
be available from a variety of sources, including Federal budgets,
State programs, and cost-share grants for non-Federal landowners, the
academic community, and nongovernmental organizations. In addition,
under section 6 of the Act, the State of Florida would be eligible for
Federal funds to implement management actions that promote the
protection and recovery of Florida leafwing and Bartram's scrub-
hairstreak butterflies. Information on our grant programs that are
available to aid species recovery can be found at: http://www.fws.gov/grants.
Although Florida leafwing and Bartram's scrub-hairstreak are only
proposed for listing under the Act at this time, please let us know if
you are interested in participating in recovery efforts for these
butterflies. Additionally, we invite you to submit any new information
on these butterflies whenever it becomes available and any information
you may have for recovery planning purposes (see FOR FURTHER
INFORMATION CONTACT).
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as
endangered or threatened and with respect to its critical habitat, if
any is designated. Regulations implementing this interagency
cooperation provision of the Act are codified at 50 CFR part 402.
Section 7(a)(4) of the Act requires Federal agencies to confer with the
Service on any action that is likely to jeopardize the continued
existence of a species proposed for listing or result in destruction or
adverse modification of proposed critical habitat. If a species is
listed subsequently, section 7(a)(2) of the Act requires Federal
agencies to ensure that activities they authorize, fund, or carry out
are not likely to jeopardize the continued existence of the species or
destroy or adversely modify its critical habitat. If a Federal action
may affect a listed species or its critical habitat, the responsible
Federal agency must enter into consultation with the Service.
Federal agency actions within these butterflies' habitat that may
require conference or consultation or both as described in the
preceding paragraph include management and any other landscape-altering
activities on Federal lands administered by the Department of Defense,
National Park Service, and U.S. Fish and Wildlife Service; construction
and maintenance of roads or highways by the Federal Highway
Administration; flood insurance and disaster relief efforts conducted
by the Federal Emergency Management Agency; and pesticide treatments
required by the U.S. Department of Agriculture or Florida Department of
Agriculture and Consumer Services in the event of emergency pest
outbreak.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to all endangered
wildlife. The prohibitions of section 9(a)(2) of the Act, codified at
50 CFR 17.21 for endangered wildlife, in part, make it illegal for any
person subject to the jurisdiction of the United States to take
(includes harass, harm, pursue, hunt, shoot, wound, kill, trap,
capture, or collect; or to attempt any of these), import, export, ship
in interstate commerce in the course of commercial activity, or sell or
offer for sale in interstate or foreign commerce any listed species.
Under the Lacey Act (18 U.S.C. 42-43; 16 U.S.C. 3371-3378), it is also
illegal to possess, sell, deliver, carry, transport, or ship any such
wildlife that has been taken illegally. Certain exceptions apply to
agents of the Service and State conservation agencies.
We may issue permits to carry out otherwise prohibited activities
involving endangered and threatened wildlife species under certain
circumstances. Regulations governing permits are codified at 50 CFR
17.22 for endangered species, and at 17.32 for threatened species. With
regard to endangered wildlife, a permit must be issued for the
following purposes: for scientific purposes, to enhance the propagation
or survival of the species, and for incidental take in connection with
otherwise lawful activities.
The Service acknowledges that it cannot fully address some of the
natural threats facing the Florida leafwing and Bartram's scrub-
hairstreak (e.g., hurricanes, tropical storms) or even some of the
other significant, long-term threats (e.g., climatic changes, sea level
rise). However, through listing, we provide protection to the known
population(s) and any new population of these butterflies that may be
discovered (see section 9 of Available Conservation Measures below).
With listing, we can also influence Federal actions that may
potentially impact these butterflies (see section 7 below); this is
especially valuable if they are found at additional locations. With
this action, we are also better able to deter illicit collection and
trade.
[[Page 49900]]
Our policy, as published in the Federal Register on July 1, 1994
(59 FR 34272), is to identify to the maximum extent practicable at the
time a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a proposed
listing on proposed and ongoing activities within the range of species
proposed for listing. We estimate that the following activities would
be likely to result in a violation of section 9 of the Act; however,
possible violations are not limited to these actions alone:
(1) Unauthorized possession, collecting, trapping, capturing,
killing, harassing, sale, delivery, or movement, including interstate
and foreign commerce, or harming or attempting any of these actions, of
the Florida leafwing or Bartram's scrub-hairstreak butterflies
(research activities where the Florida leafwing or Bartram's scrub-
hairstreak are handled, captured (e.g., netted, trapped), marked, or
collected will require authorization pursuant to the Act).
(2) Incidental take of the Florida leafwing or Bartram's scrub-
hairstreak without authorization pursuant to section 7 or section
10(a)(1)(B) of the Act.
(3) Sale or purchase of specimens of these taxa, except for
properly documented antique specimens at least 100 years old, as
defined by section 10(h)(1) of the Act.
(4) Unauthorized destruction or alteration of the Florida leafwing
or Bartram's scrub-hairstreak habitat (including unauthorized grading,
leveling, plowing, mowing, burning, herbicide spraying, or pesticide
application) in ways that kills or injures individuals by significantly
impairing these butterflies' essential breeding, foraging, sheltering,
or other essential life functions.
(5) Unauthorized use of pesticides or herbicides resulting in take
of the Florida leafwing or Bartram's scrub-hairstreak butterflies.
(6) Unauthorized release of biological control agents that attack
any life stages of these taxa.
(7) Unauthorized removal or destruction of pineland croton, the
hostplant utilized by the Florida leafwing or Bartram's scrub-
hairstreak butterflies, within areas used by the butterflies that
result in harm to the butterflies.
(8) Release of nonnative species into occupied Florida leafwing and
Bartram's scrub-hairstreak habitat that may displace the butterflies or
their native host plants.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Field
Supervisor of the Service's South Florida Ecological Services Office
(see FOR FURTHER INFORMATION CONTACT). Requests for copies of
regulations regarding listed species and inquiries about prohibitions
and permits should be addressed to the U.S. Fish and Wildlife Service,
Ecological Services Division, Endangered Species Permits, 1875 Century
Boulevard, Atlanta, GA 30345 (Phone 404-679-7140; Fax 404-679-7081).
Peer Review
In accordance with our joint policy on peer review published in the
Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert
opinions of at least three appropriate and independent specialists
regarding this proposed rule. The purpose of peer review is to ensure
that our listing designation is based on scientifically sound data,
assumptions, and analyses. We have invited these peer reviewers to
comment during this public comment period.
We will consider all comments and information received during this
comment period on this proposed rule during our preparation of a final
determination. Accordingly, the final decision may differ from this
proposal.
Public Hearings
Section 4(b)(5) of the Act provides for one or more public hearings
on this proposal, if requested. Requests must be received within 45
days after the date of publication of this proposed rule in the Federal
Register. Such requests must be sent to the address shown in FOR
FURTHER INFORMATION CONTACT. We will schedule public hearings on this
proposal, if any are requested, and announce the dates, times, and
places of those hearings, as well as how to obtain reasonable
accommodations, in the Federal Register and local newspapers at least
15 days before the hearing.
Required Determinations
Clarity of the Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(1) Be logically organized;
(2) Use the active voice to address readers directly;
(3) Use clear language rather than jargon;
(4) Be divided into short sections and sentences; and
(5) Use lists and tables wherever possible.
If you feel that we have not met these requirements, send us
comments by one of the methods listed in the ADDRESSES section. To
better help us revise the rule, your comments should be as specific as
possible. For example, you should tell us the numbers of the sections
or paragraphs that are unclearly written, which sections or sentences
are too long, the sections where you feel lists or tables would be
useful, etc.
National Environmental Policy Act (NEPA)
We have determined that environmental assessments and environmental
impact statements, as defined under the authority of the National
Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.), need not be
prepared in connection with listing a species as an endangered or
threatened species under the Endangered Species Act. We published a
notice outlining our reasons for this determination in the Federal
Register on October 25, 1983 (48 FR 49244).
References Cited
A complete list of references cited in this rulemaking is available
on the Internet at http://www.regulations.gov and upon request from the
South Florida Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Authors
The primary authors of this proposed rule are the staff members of
the South Florida Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C.
4201-4245; unless otherwise noted.
0
2. In Sec. 17.11(h) add new entries for ``Butterfly, Bartram's scrub-
hairstreak'' and ``Butterfly, Florida leafwing'' to the List of
Endangered and Threatened
[[Page 49901]]
Wildlife in alphabetical order under Insects to read as set forth
below:
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate
------------------------------------------------ population where Critical Special
Historic range endanged or Status Family When listed habitat rules
Common name Scientific name threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * * * *
Insects
* * * * * * *
Butterfly, Bartram's scrub- Strymon acis U.S.A. (FL)..... Entire.......... E Lycaenidae..... ........... ........... NA
hairstreak. bartrami.
* * * * * * *
Butterfly, Florida leafwing.. Anaea troglodyta U.S.A. (FL)..... Entire.......... E Nymphalidae.... ........... ........... NA
floridalis.
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dated: August 2, 2013.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2013-19794 Filed 8-14-13; 8:45 am]
BILLING CODE 4310-55-P