# Endangered and Threatened Wildlife and Plants; Listing of the Miami Blue Butterfly as Endangered Throughout Its Range; Listing of the Cassius Blue, Ceraunus Blue, and Nickerbean Blue Butterflies as Threatened Due to Similarity of Appearance to the Miami Blue Butterfly in Coastal South and Central Florida

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A2012-8088

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** April 6, 2012
- **Citation:** 77 FR 20948

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2011-0043; 4500030113]
RIN 1018-AX83
Endangered and Threatened Wildlife and Plants; Listing of the Miami Blue Butterfly as Endangered Throughout Its Range; Listing of the Cassius Blue, Ceraunus Blue, and Nickerbean Blue Butterflies as Threatened Due to Similarity of Appearance to the Miami Blue Butterfly in Coastal South and Central Florida

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the Fish and Wildlife Service (Service), are listing the Miami blue butterfly
(Cyclargus thomasi bethunebakeri),
as endangered under the Endangered Species Act of 1973, as amended (Act). We have determined that designation of critical habitat for the Miami blue butterfly is not prudent at this time. We also are listing the cassius blue butterfly
(Leptotes cassius theonus),
ceraunus blue butterfly
(Hemiargus ceraunus antibubastus),
and nickerbean blue butterfly
(Cyclargus ammon)
as threatened due to similarity of appearance to the Miami blue in coastal south and central Florida, and establishing a special rule under section 4(d) of the Act for these three species.

DATES:

This final rule becomes effective on April 6, 2012.

ADDRESSES:

This final rule is available on the Internet at
http://www.regulations.gov
and
http://www.fws.gov/verobeach/.
Comments and materials received, as well as supporting documentation used in the preparation of this rule, will be available for inspection, by appointment, during normal business hours at the U.S. Fish and Wildlife Service, South Florida Ecological Services Office, 1339 20th Street, Vero Beach, Florida 32960-3559; telephone 772-562-3909; facsimile 772-562-4288.

FOR FURTHER INFORMATION CONTACT:

Larry Williams, Field Supervisor, U.S. Fish and Wildlife Service, South Florida Ecological Services Office (see
ADDRESSES
above). If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

This document consists of: (1) A final rule to list the Miami blue butterfly
(Cyclargus thomasi bethunebakeri)
as endangered; and (2) a special rule pursuant to section 4(d) of the Act to list the cassius blue butterfly
(Leptotes cassius theonus),
ceraunus blue butterfly
(Hemiargus ceraunus antibubastus),
and nickerbean blue butterfly
(Cyclargus ammon)
as threatened due to similarity of appearance to the Miami blue in portions of their ranges.

Why we need to publish a rule.
Under the Act, a species or subspecies may warrant protection through listing if it is endangered or threatened throughout all or a significant portion of its range. On August 10, 2011, we published emergency and proposed rules to list the Miami blue butterfly as endangered. In those documents we explained that the subspecies currently exists in a fraction of its historical range and faces numerous threats, and therefore qualifies for listing. This rule finalizes the protection proposed for the subspecies, following careful consideration of all comments received during the public comment period. One of the principal threats to the subspecies is collection for commercial purposes. For this reason, we are also prohibiting the collection of the cassius, ceraunus, and nickerbean blue butterflies, three species which are very similar in appearance to the Miami blue butterfly, within the historical range of the Miami blue.

The basis for our action.
Under the Act, a species may be determined to be endangered or threatened based on any of five factors: (1) Destruction, modification, or curtailment of its habitat or range; (2) Overutilization; (3) Disease or predation; (4) Inadequate existing regulations; or (5) Other natural or manmade factors. The Miami blue is endangered due to four of these five factors. Section 4(e) of the Act also allows for the extension of protections to similar species under certain circumstances.

Peer reviewers support our methods.
We solicited opinions from knowledgeable individuals with scientific expertise to review the technical assumptions, analyses, adherence to regulations, and whether or not we had used the best available information in our proposed listing rule for the subspecies. We received 8 peer review responses, and 2 collaborative responses from State agencies. These peer reviewers generally concurred with the basis for listing the Miami blue, and provided additional information, clarifications, and suggestions to improve this final listing determination.

Acronyms Used in This Document

We use many acronyms throughout this final rule. To assist the reader, we provide a list of these acronyms here for easy reference:

AME = Allyn Museum of Entomology

BHSP = Bahia Honda State Park

BNP = Biscayne National Park

CCSP = U.S. Climate Change Science Program

CITES = Convention on International Trade in Endangered Species

DJSP = Dagny Johnson Key Largo Hammock Botanical State Park

ENP = Everglades National Park

FCCMC = Florida Coordinating Council on Mosquito Control

FDEP = Florida Department of Environmental Protection

FKMCD = Florida Keys Mosquito Control District

FLMNH = Florida Museum of Natural History

FPS = Florida Park Service

FWC = Florida Fish and Wildlife Conservation Commission

GWHNWR = Great White Heron National Wildlife Refuge

INRMP = Integrated Natural Resource Management Plan

IPCC = Intergovernmental Panel on Climate Change

IRC = Institute for Regional Conservation

KWNWR = Key West National Wildlife Refuge

MIT = Massachusetts Institute of Technology

NABA = North American Butterfly Association

NAS = Naval Air Station Key West

NCSU = North Carolina State University

NEP = nonessential experimental populations

NKDR = National Key Deer Refuge

TNC = The Nature Conservancy

UF = University of Florida

UN = United Nations

USDJ = U.S. Department of Justice

USGS = U.S. Geological Survey

Previous Federal Actions

Federal actions for the Miami blue butterfly prior to August 10, 2011, are outlined in our emergency rule (76 FR 49542), which was published on that date. Publication of the proposed rule (76 FR 49408), concurrently published on that date, opened a 60-day comment period, which closed on October 11, 2011. The emergency rule provides protection for the Miami blue, ceraunus blue, nickerbean blue, and cassius blue butterflies for a 240-day period, ending on April 6, 2012. Because of this time constraint, and the threat of collection of these species if the emergency rule expires before the proposed rule is finalized (see Factor B, Overutilization for commercial, recreational, scientific, or educational purposes), this rule does not have the standard 30-day period

before becoming effective. It becomes effective upon the expiration of the emergency rule, April 6, 2012.

Public Comments

We received comments from the public on the proposed listing action, including the proposed listing of three similar butterflies due to similarity of appearance and our determination that designation of critical habitat is not prudent. In this rule, we respond to these issues in a single comment section.

Background

The Miami blue is a small, brightly colored butterfly approximately 0.8 to 1.1 inches (1.9 to 2.9 centimeters [cm]) in length (Pyle 1981, p. 488), with a forewing length of 0.3 to 0.5 inches (8.0 to 12.5 millimeters) (Minno and Emmel 1993, p. 134). Wings of males are blue above (dorsally), with a narrow black outer border and white fringes; females are bright blue dorsally, with black borders and an orange/red and black eyespot near the anal angle of the hindwing (Comstock and Huntington 1943, p. 98; Minno and Emmel 1993, p. 134). The underside is grayish, with darker markings outlined with white and bands of white wedges near the outer margin. The ventral hindwing has two pairs of eyespots, one of which is capped with red; basal and costal spots on the hindwing are black and conspicuous (Minno and Emmel 1993, p. 134). The winter (dry season) form is much lighter blue than the summer (wet season) form and has narrow black borders (Opler and Krizek 1984, p. 112). Seasonal wing pattern variation may be caused by changes in humidity, temperature, or length of day (Pyle 1981, p. 489). Miami blue larvae are bright green with a black head capsule, and pupae vary in color from black to brown (Minno and Emmel 1993, pp. 134-135).

The Miami blue is similar in appearance to three other sympatric (occupying the same or overlapping geographic areas, without interbreeding) butterfly species that occur roughly in the same habitats: cassius blue
(Leptotes cassius theonus),
ceraunus blue
(Hemiargus ceraunus antibubastus),
and nickerbean blue
(Cyclargus ammon).
The Miami blue is slightly larger than the ceraunus blue (Minno and Emmel 1993, p. 134), and the ceraunus blue has a different ventral pattern and flies close to the ground in open areas (Minno and Emmel 1994, p. 647). The cassius blue often occurs with the Miami blue, but has dark bars rather than spots on the undersides of the wings (Minno and Emmel 1994, p. 647). The Miami blue can be distinguished from the ceraunus blue and cassius blue by its very broad white ventral submarginal band, the dorsal turquoise color of both sexes, and the orange-capped marginal eyespot on the hind wings (Opler and Krizek 1984, p. 112). The nickerbean blue is also similar to the Miami blue in general appearance but is considerably smaller; it has three black spots across the basal hindwing, while the Miami blue has four (Calhoun
et al.
2002, p. 15). The larvae and pupae of the nickerbean blue closely resemble the Miami blue (Calhoun
et al.
2002, p. 15).

In a comparison of Miami blue butterfly specimens within the Florida Museum of Natural History (FLMNH) collection, Saarinen (2009, pp. 42-43) found a significant difference in forewing length between males and females, with males having shorter forewings than females. However, no significant differences were found between forewing length in comparing wet and dry seasons, decade of collection, seven different regions, or between eastern mainland and Keys specimens (Saarinen 2009, pp. 42-43). No seasonal size differences were found between the mainland populations and those in the Keys (Saarinen 2009, p. 43).

In a comparison of body size in a recent Miami blue population, females were significantly larger than males, and individuals sampled in the wet season were also significantly larger than in the dry season (Saarinen 2009, p. 43). In a comparison of recent Bahia Honda State Park (BHSP) individuals with specimens from historical collections (FLMNH data), BHSP individuals were significantly larger than historical specimens, females from BHSP were significantly larger than historical female specimens, and BHSP adults measured in wet seasons were larger than those sampled in wet seasons in museum collections (Saarinen 2009, p. 43). Saarinen (2009, p. 47) suggested that perhaps larger adults were selected for over time with larger adults being more capable of dispersing and finding food and mates. Limited food resources during larval development or abrupt termination of availability of food in the last larval instar can lead to early pupation and a smaller adult size (T.C. Emmel, pers. comm., as cited in Saarinen 2009, p. 47). It is possible that differences in host plant (
e.g.,
nutrition) and age of specimens (
e.g.,
freshness) may also be factors when comparing body size between recent specimens and those from historical collections.

Taxonomy

The Miami blue belongs to the family Lycaenidae (Leach), subfamily Polyommatinae (Swainson). The species
Hemiargus thomasi
was originally described by Clench (1941, pp. 407-408), and the subspecies
Hemiargus thomasi bethunebakeri
was first described by Comstock and Huntington (1943, p. 97). Although some authors continue to use
Hemiargus,
Nabokov (1945, p. 14) instituted
Cyclargus
for some species, which has been supported by more recent research (Johnson and Balint 1995, pp. 1-3, 8-11, 13; Calhoun
et al.
2002, p. 13; K. Johnson, Florida State Collection of Arthropods,
in litt.
2002). There are differences in the internal genitalic structures of the genera
Hemiargus
and
Cyclargus
(Johnson and Balint 1995, pp. 2-3, 11; K. Johnson,
in litt.
2002). Kurt Johnson (
in litt.
2002), who has published most of the existing literature since 1950 on the blue butterflies of the tribe Polyommatini, reaffirmed that
thomasi
belongs in the genus
Cyclargus
(Nabokov 1945, p. 14), not
Hemiargus.
Accordingly,
Cyclargus thomasi bethunebakeri
(Pelham 2008, p. 21) and its taxonomic standing is accepted (Integrated Taxonomic Information System 2011, p. 1).

In 2003, questions about the taxonomic identity of Miami blues from BHSP were raised by a few individuals. To address these questions, the Service sent two pairs (male and female) of adult specimens to three independent taxonomists and reviewers (Dr. Jacqueline Miller, Associate Curator, Allyn Museum of Entomology (AME), FLMNH; Dr. Paul Opler, Colorado State University; and John Calhoun, Museum of Entomology, Florida State Collection of Arthropods) for verification. To avoid harm to the wild population, scientists examined moribund adults from a captive colony generated from individuals taken from BHSP. Each reviewer independently confirmed through various means (
e.g.,
comparison with confirmed specimens, dissection and examination of genitalia) that the identities of the adult specimens examined were
Cyclargus thomasi bethunebakeri
(J. Miller,
in litt.
2003; P. Opler,
in litt.
2003; J. Calhoun,
in litt.
2003a). We received an additional confirmation from Lee Miller, Curator (AME, FLMNH), stating that the identities of the adult specimens examined were
Cyclargus thomasi bethunebakeri
(L. Miller,
in litt.
2003). Taxonomic verification by genitalic dissection of the Miami blue at Key West National Wildlife Refuge (KWNWR) has not occurred, but preliminary molecular evidence has confirmed that they are the same taxon (E.V. Saarinen, unpub. data, as cited in

Saarinen 2009, p. 18; E. Saarinen,
in litt.
2011).

Life History

Like all butterflies, the Miami blue undergoes complete metamorphosis, with four life stages (egg, caterpillar or larva, pupa or chrysalis, and adult). The generation time is approximately 30-40 days (Carroll and Loye 2006, p. 19; Saarinen 2009, pp. 22, 76) and similar for both males and females (Trager and Daniels 2011, p. 35). Although a single Miami blue female can lay 300 eggs, high mortality may occur in the immature larval stages prior to adulthood (T. Emmel, University of Florida [UF], pers. comm. 2002). Trager and Daniels (2011, p. 40) indicated that larger, longer-lived females demonstrate a higher fecundity. Reported host plants are blackbead (
Pithecellobium
spp.), nickerbean (
Caesalpinia
spp.), balloonvine (
Cardiospermum
spp.), and presumably
Acacia
spp. (Kimball 1965, p. 49; Lenczewski 1980, p. 47; Pyle 1981, p. 489; Opler and Krizek 1984, p. 113; Minno and Emmel 1993, p. 134; Calhoun
et al.
2002, p. 18; Cannon
et al.
2010, p. 851). In addition, Rutkowski (1971, p. 137) observed a female laying one egg just above the lateral bud on snowberry
(Chiococca alba).
Eggs are laid singly near the base of young pods or just above the lateral buds of balloonvine and the flowers of leguminous trees (Opler and Krizek 1984, p. 113; Minno and Emmel 1993, p. 134); flower buds and young tender leaves of legumes are preferred laying sites (Minno and Minno 2009, p. 78; M. Minno, pers. comm. 2010).

On nickerbean plants (
Caesalpinia
spp.), females lay eggs on developing shoots, foliage, and flower buds (Saarinen 2009, p. 22; Trager and Daniels 2011, p. 35). Oviposition occurs throughout the day with females often seeking terminal growth close to the ground (<3.3 feet [<1 meter]) or in locations sheltered from the wind (Emmel and Daniels 2004, p. 13). Eggs are generally laid singly, but may be clustered on developing leaves, shoot tips, and flower buds (Saarinen 2009, p. 22). After several days of development, larvae chew out of eggs and develop through four instar stages, with total larval development time lasting 3 to 4 weeks, depending upon temperature and humidity (Saarinen 2009, p. 22). Fourth instar larvae pupate in sheltered or inconspicuous areas, often underneath leaf whorls or bracts (Saarinen 2009, p. 22). Adult butterflies eclose (emerge) after 5 to 8 days, depending on temperature and humidity (Saarinen 2009, p. 22).

On blackbead plants, females lay eggs on flower buds and emerging leaves (Cannon
et al.
2010, p. 851; Trager and Daniels 2011, p. 35). Oviposition on, or larval consumption of, mature blackbead leaves was not observed (Cannon
et al.
2010, p. 851). Thus, Cannon
et al.
(2010, p. 851) suggested that abundance may be limited by the availability of young blackbead leaves and buds for egg-laying, even if abundant suitable nectar sources (see
Habitat
) are available year-round.

On balloonvine, females lay single eggs near fruit (capsules) (Carroll and Loye 2006, p. 18). Newly hatched larvae chew distinctive holes through the outer walls of the capsules to access seeds (Minno and Emmel 1993, p. 134). After consuming seeds within the natal capsule, larvae must crawl to a sequence of two or three balloons before growing large enough to pupate. Attending ants follow through the same holes (see Interspecific relationships below). Miami blues were also observed to commonly pupate within mature capsules (sometimes with ants in attendance within the capsule) (Carroll and Loye 2006, p. 20).

The Miami blue has been described as having multiple, overlapping broods year-round (Pyle 1981, p. 489). Adults can be found every month of the year (Opler and Krizek 1984, pp. 112-113; Minno and Emmel 1993, p. 135; 1994, p. 647; Emmel and Daniels 2004, p. 9; Saarinen 2009, p. 22). Opler and Krizek (1984, pp. 112-113) indicated one long winter generation from December to April, during which time the adults are probably in reproductive diapause (a period in which growth, development, and physiological activity is suspended or diminished); a succession of shorter generations was thought to occur from May through November, the exact number of which is unknown. Glassberg
et al.
(2000, p. 79) described the Miami blue as having occurred all year, with three or more broods. Researchers have noted a marked decrease of adults from December to early February at BHSP, indicative of a short diapause (Emmel and Daniels 2003, p. 3; 2004, p. 9). Saarinen also noted that the life cycle at BHSP slowed in winter months and suspected a slight diapause (E.V. Saarinen and J.C. Daniels, unpub. data, as cited in Saarinen 2009, p. 22). Conversely, Minno (pers. comm. 2010) noted that there have been records of adults in December and January and suggested that this tropical butterfly may not have a winter diapause, but rather, emergence may be delayed by cold temperatures in some years. Salvato and Salvato (2007, p. 163) and Cannon
et al.
(2010, pp. 849-850) also reported numerous adults at BHSP and KWNWR, respectively, during winter months.

Information on adult lifespan is limited. Based on field studies, adult Miami blues have been found to live 9 days, but most adults are thought to live only a few days (J. Daniels, UF, pers. comm. 2003a, 2003b). In general, adults may survive less than a week in the wild; there are approximately 8-10 generations per year (Saarinen
et al.
2009a, p. 31). Generations are not completely discrete due to the variance in development time of all life stages (Saarinen
et al.
2009a, p. 31). Adult longevity is not well understood. Some lycaenids have the ability to survive longer than mark-recapture studies indicate (Johnson
et al.
2011, p. 8). For example, the Palos Verdes blue (
Glaucopsyche lygdamus palosverdesensis
), thought to live 10 days or less in the field, has been documented to have a life span of up to 38 days in the laboratory (T. Longcore, University of California,
in litt.
2011; Johnson
et al.
2011, p. 8). Additional field studies are needed to better ascertain adult Miami blue longevity in the wild.

Range size and dispersal—At this time, it is unclear how far adult Miami blues can disperse and the mechanisms for dispersal (
i.e.,
active [flight] or passive [wind-assisted]). Initial mark-recapture studies of the butterfly indicate they are nonmigratory and appear to be sedentary (Emmel and Daniels 2004, p. 6). Based on mark-recapture work conducted in 2002-2003, recaptured adults (N=39) moved an average of 6.53 +/−11.68 feet (2.0 +/−3.6 meters), four individuals moved between 25 and 50 feet (7.6 and 15.2 meters), and only three individuals moved more than 50 feet (15.2 meters) over a few days (Emmel and Daniels 2004, pp. 6, 32-38). Few individuals were found to move between the lower and upper walkway locations of the south end colony sites at BHSP (approximately 100 feet [30.5 meters]); no movement between any of the smaller individual, isolated colony sites was recorded (Emmel and Daniels 2004, p. 6). However, Saarinen (2009, pp. 73, 78-79) found that genetic exchange between colonies occurred at BHSP and noted that small habitat patches may be crucial in providing links between subpopulations in an area.

Interspecific relationships—As in many lycaenids worldwide (Pierce
et al.
2002, p. 734), Miami blue larvae associate with ants (Emmel 1991, p. 13; Minno and Emmel 1993, p. 135; Carroll and Loye 2006, pp. 19-20; Trager and Daniels 2011, p. 35) in at least four

genera of ants in three subfamilies of Formicidae (Saarinen and Daniels 2006, p. 71; Saarinen 2009, pp. 131, 133). Miami blues using nickerbean at BHSP and Everglades National Park (ENP) (reintroduced individuals) were variously tended by
Camponotus floridanus, C. planatus, Crematogaster ashmeadi, Forelius pruinosus,
and
Tapinoma melanocephalum
(Saarinen and Daniels 2006, p. 71; Saarinen 2009, pp. 131, 138).
C. floridanus
was the primary ant symbiont, commonly found tending larvae; other ant species were encountered less often (Saarinen and Daniels 2006, p. 70; Saarinen 2009, pp. 131-132). Liquid (honeydew) exuded from the butterfly's dorsal nectary organ (honey gland) was actively imbibed by all species of ants (Saarinen and Daniels 2006, p. 70; Saarinen 2009, p. 132).

Late Miami blue instars were always found in association with ants, but early instars, prepupae, and pupae were frequently found without ants present (Saarinen and Daniels 2006, p. 70).
Forelius pruinosus
and
Tapinoma melanocephalum
were observed to derive honeydew from Miami blues they tended, but were not observed to actively protect them from any predator (Saarinen and Daniels 2006, p. 71; Saarinen 2009, p. 133). However, the presence of ants in the vicinity of larvae may potentially deter predators (Saarinen and Daniels 2006, pp. 71, 73; Saarinen 2009, p. 133; Trager and Daniels 2009, p. 480). Two additional ants,
Paratrechina longicornis
and
P. bourbonica,
have been identified as potential associates of the Miami blue (Saarinen and Daniels 2006, pp. 70-71; Saarinen 2009, pp. 131, 138).
P. longicornis
was found near Miami blue larvae and appeared to tend them during brief encounters;
P. bourbonica
tended another lycaenid, martial scrub-hairstreak (
Strymon martialis
) at BHSP (Saarinen and Daniels 2006, p. 70). Cannon
et al.
(2007, p. 16) also observed two ant species attending Miami blues on KWNWR. Based on photographs, the ants appeared to be
Camponotus inaequalis
and
P. longicornis. C. planatus
was observed on blackbead.

In the 1980s, Miami blue larvae that fed on balloonvine in the upper Keys were also tended by ants (
Camponotus floridanus
and
C. planatus
) (Carroll and Loye 2006, pp. 19-20). Carroll and Loye (2006, p. 20) found that
Camponotus
spp. raised with Miami blue larvae lived longer than ants raised with larvae of other lycaenid species or without any food source, demonstrating that larval secretions benefit ants.

More recently, Trager and Daniels (2009, p. 479) most commonly found
Camponotus floridanus
and
C. planatus
associated with wild and recently released Miami blue larvae. In a comparison of Miami blue larvae raised with and without ants, no effect of ant presence was found on any measurements of larval performance (
e.g.,
age at pupation, pupal mass, length of pupation, total time as an immature) (Trager and Daniels 2009, p. 480). Miami blue larval development was found to be similar to that of other conspecific lycaenid species not tended by ants (Trager and Daniels 2009, p. 480). Although the relationships are not completely understood, it appears that Miami blue larvae may receive some benefits from tending ants (
e.g.,
potential defense from predators) without much, if any, costs incurred.

Habitat

The Miami blue is a coastal butterfly reported to occur in openings and around the edges of hardwood hammocks (forest habitats characterized by broad-leaved evergreens), and in other communities adjacent to the coast that are prone to frequent natural disturbances (
e.g.,
coastal berm hammocks, dunes, and scrub) (Opler and Krizek 1984, p. 112; Minno and Emmel 1994, p. 647; Emmel and Daniels 2004, p. 12). It also has been reported to use tropical pinelands (Minno and Emmel 1993, p. 134) and open sunny areas along trails (Pyle 1981, p. 489). In the Keys, it was most abundant near disturbed hammocks where weedy flowers provided nectar (Minno and Emmel 1994, p. 647). It also occurred in pine rocklands (fire-dependent slash pine community with palms and a grassy understory) on Big Pine Key (Minno and Emmel 1993, p. 134; Calhoun
et al.
2002, p. 18) and elsewhere in Monroe and Miami-Dade Counties. In Miami-Dade County, it occurred locally inland, sometimes in abundance (M. Minno, pers. comm. 2010). Within KWNWR, all occupied areas had coastal strands and dunes fronted by beaches (Cannon
et al.
2007, p. 13; Cannon
et al.
2010, p. 851).

Larval host plants include blackbead, nickerbean, balloonvine, and presumably
Acacia
spp. (Dyar 1900, pp. 448-449, Kimball 1965, p. 49; Lenczewski 1980, p. 47; Pyle 1981, p. 489; Calhoun
et al.
2002, p. 18). Gray nickerbean
(Caesalpinia bonduc)
is widespread and common in coastal south Florida. Following disturbances, it can dominate large areas (K. Bradley, The Institute for Regional Conservation [IRC], pers. comm. 2002). Gray nickerbean has been recorded as far north as Volusia County on the east coast, matching the historical range of the Miami blue, and Levy County on the west coast (J. Calhoun, pers. comm. 2003b). The Miami blue is also reported to use peacock flower (
Caesalpinia pulcherrima
) (Matteson 1930, pp. 13-14; Calhoun
et al.
2002, p. 18), a widely cultivated exotic that occurs in disturbed uplands and gardens (Gann
et al.
2001-2012, p. 1). Rutkowski (1971, p. 137) and Opler and Krizek (1984, p. 113) reported the use of snowberry. Brewer (1982, p. 22) reported the use of cat's paw blackbead
(Pithecellobium unguis-cati)
on Sanibel Island in Lee County.

Prior to the 1970s, documented host plants for the butterfly were nickerbean and blackbead (J. Calhoun, pers. comm. 2003b). Balloonvine (
Cardiospermum
spp.) was not reported as a host plant until the 1970s, when these plants seemed to have become common in extreme southern Florida (J. Calhoun, pers. comm. 2003b). Subsequently, balloonvine (
Cardiospermum halicacabum
), an exotic species in Florida, was the most frequently reported host plant for Miami blue (
e.g.,
Lenczewski 1980, p. 47; Opler and Krizek 1984, p. 113; Minno and Emmel 1993, p. 134; 1994, p. 647; Calhoun
et al.
2002, p. 18). However, Carroll and Loye (2006, pp. 13-15) corrected “the common view that a principal host plant, balloonvine, is an exotic weed.” They found that published reports of Miami blue larvae on balloonvine all identified the host as
C. halicacabum
and stated that the butterfly was instead dependent upon a declining native,
C. corindum
(Carroll and Loye 2006, pp. 14, 23). Bradley (pers. comm. 2002) also confirmed that
C. halicacabum
does not occur in the Keys, noting that the native balloonvine (
C. corindum
) is relatively common and widespread in the Keys and has been commonly mistaken as
C. halicacabum
in the Keys and other sites in south Florida.

Calhoun (pers. comm. 2003b) suggested that the Miami blue may simply utilize whatever acceptable hosts are available under suitable conditions. According to Calhoun (pers. comm. 2003b), a review of the historical range of the butterfly and its host plants suggests balloonvine was a more recent larval host plant and temporarily surpassed nickerbean as the primary host plant. As native coastal habitats were destroyed, balloonvine readily invaded disturbed environments, and the Miami blue used what was most commonly available. Minno (pers. comm. 2010) suggested that the Miami blue used balloonvine on Key Largo and Plantation Key extensively in the 1970s through the 1990s, noting that nickerbean, blackbead, and perhaps

other hosts were also probably used, but not documented.

The Miami blue metapopulation (series of small populations that have some level of interaction) at KWNWR was found to rely upon Florida Keys blackbead as the singular host plant (Cannon
et al.
2007, p. 1; Cannon
et al.
2010, pp. 851-852). Blackbead was also an important nectar plant when in flower. High counts of Miami blues at KWNWR were generally associated with the emergence of flowers and new leaves on blackbead (Cannon
et al.
2007, pp. 14-15; Cannon
et al.
2010, pp. 851-852). All sites that supported Miami blues contained blackbead (Cannon
et al.
2007, p. 6; Cannon
et al.
2010, p. 851). Limited abundance of blackbead within select areas of KWNWR was thought to limit abundance of the Miami blue (Cannon
et al.
2007, p. 10; Cannon
et al.
2010, p. 850). At BHSP, the Miami blue was closely associated with gray nickerbean, but also used blackbead (M. Minno, pers. comm. 2010). In KWNWR, gray nickerbean was rare, with only a few small plants on Boca Grande Key and the Marquesas Keys (Cannon
et al.
2010, p. 851).

Adult Miami blues have been reported to feed on a wide variety of nectar sources, including Spanish needles (
Bidens alba
), Leavenworth's tickseed (
Coreopsis leavenworthi
), scorpionstail (
Heliotropium angiospermum
), turkey tangle fogfruit or capeweed (
Lippia nodiflora
), buttonsage (
Lantana involucrata
), snow squarestem (
Melanthera nivea
[
M. aspera
]), blackbead, Brazilian pepper (
Schinus terebinthifolius
), false buttonweed (
Spermacoce
spp.), and seaside heliotrope (
Heliotropium curassavicum
) (Pyle 1981, p. 489; Opler and Krizek 1984, p. 113; Minno and Emmel 1993, p. 135; Emmel and Daniels 2004, p. 12). Emmel and Daniels (2004, p. 12) reported that the Miami blue uses a variety of flowering plant species in the Boraginaceae, Asteraceae, Fabaceae, Polygonaceae, and Verbenaceae families for nectar. Cannon
et al.
(2010, p. 851) found the butterfly uses nine plant species as nectar sources within KWNWR, including: blackbead, snow squarestem, coastal searocket (
Cakile lanceolata
), black torch (
Erithalis fruticosa
), yellow joyweed (
Alternanthera flavescens
), bay cedar (
Suriana maritime
), sea lavender (
Argusia gnaphalodes
), seaside heliotrope, and sea purslane (
Sesuvium portulacastrum
).

Nectar sources must be near potential host plants since the butterflies are presumably sedentary and may not travel between patches of host and nectar sources (Emmel and Daniels 2004, p. 13). This may help explain the absence of the Miami blue from areas in which host plants are abundant and nectar sources are limited (J. Calhoun, pers. comm. 2003b). Emmel and Daniels (2004, p. 13) argued that it is potentially critical that sufficient available adult nectar sources be directly adjacent to host patches and also important that a range of potential nectar sources be available in the event one plant species goes out of flower or is adversely impacted by environmental factors. Cannon
et al.
(2010, p. 851) suggested that the growth stage of blackbead, coupled with abundant nectar from herbaceous plants, likely influenced Miami blue abundance; the highest counts occurred when blackbead was flowering profusely and producing new leaves.

Historical Distribution

The Miami blue butterfly (
Cyclargus thomasi bethunebakeri
) is endemic to Florida with additional subspecies occurring in the Caribbean (Smith
et al.
1994, p. 129; Hernandez 2004, p. 100; Saarinen 2009, pp. 18-19, 28). Field guides and other sources differ as to whether
C. thomasi bethunebakeri
occurs in the Bahamas. Clench (1963, p. 250), who collected butterflies in the West Indies, indicated that the subspecies occurred only in Florida. Riley (1975, p. 110) and Calhoun
et al.
(2002, p. 13) indicated that the Miami blue of Florida rarely occurs as a stray in the Bahamas. Minno and Emmel (1993, p. 134; 1994, p. 647) and Calhoun (1997, p. 46) considered the Miami blue to occur only in Florida (endemic to Florida, with other subspecies found in the Bahamas and Greater Antilles). Smith
et al.
(1994, p. 129) indicated that the Miami blue occurs in southern Florida, but noted it has been recorded from the Bimini Islands in the Bahamas. However, in a recent comprehensive study of museum specimens, Saarinen (2009, p. 28) found no specimens in current museum holdings to verify this. Overall, the majority of historical records pertaining to this subspecies' distribution are dominated by Florida occurrences, with any peripheral occurrences in the Bahamas possibly being ephemeral in nature.

Although information on distribution is somewhat limited, it is clear that the historical range of the Miami blue has been significantly reduced. The type series (
i.e.,
the original set of specimens on which the description of the species is based) contains specimens ranging from Key West up the east coast to Volusia County (Comstock and Huntington 1943, p. 98; J. Calhoun, pers. comm., 2003b). Opler and Krizek (1984, p. 112) showed its historical range as being approximately from Tampa Bay and Cape Canaveral southward along the coasts and through the Keys. It has also been collected in the Dry Tortugas (Forbes 1941, pp. 147-148; Kimball 1965, p. 49; Glassberg and Salvato 2000, p. 2). Lenczewski (1980, p. 47) noted that it was reported as extremely common in the Miami area in the 1930s and 1940s. Calhoun
et al.
(2002, p. 17) placed the historical limits of the subspecies' northern distribution at Hillsborough and Volusia Counties, extending southward along the coasts to the Marquesas Keys (west of Key West).

The Miami blue was most common on the southern mainland and the Keys, especially Key Largo and Big Pine Key (Calhoun
et al.
2002, p. 17) and other larger keys with hardwood hammock (Monroe County) (M. Minno, pers. comm. 2010). The subspecies was recorded on at least 10 islands of the Keys (Adams Key, Big Pine Key, Elliott Key, Geiger Key, Key Largo, Lignumvitae Key, Old Rhodes Key, Plantation Key, Stock Island, Sugarloaf Key) (Minno and Emmel 1993, p. 134). On the Gulf coast, it was reportedly more localized and tended to occur on more southerly barrier islands (J. Calhoun, pers. comm. 2003b). According to Calhoun
et al.
(2002, p. 17), the Miami blue occupied areas on the barrier islands of Sanibel, Marco, and Chokoloskee, along the west coast into the 1980s (based upon Brewer 1982, p. 22; Minno and Emmel 1994, pp. 647-648). Lenczewski (1980, p. 47) reported that the Miami blue historically occurred at Chokoloskee, Royal Palm (Miami-Dade County), and Flamingo (Monroe County) within ENP, but that the subspecies has not been observed in ENP since 1972.

Based upon examination of specimens from museum collections (N = 689), Saarinen (2009, pp. 42, 55-57) found a large, primarily coastal, geographic distribution for the butterfly. Most specimens from an 11-county area from 1900 to 1990 were collected in Miami-Dade and Monroe Counties (Saarinen 2009, pp. 42, 58). Records from Miami-Dade County (N = 212) were most numerous in the 1930s and 1940s; records from Monroe County (N = 387) (including all of the Florida Keys) were most numerous in the 1970s (Saarinen 2009, pp. 42, 58). Saarinen (2009, p. 47) was not able to quantify issues of collector bias and noted that collecting restrictions, inaccessibility of certain islands, and targeted interest in certain areas may have been factors influencing the relative abundance (and distribution) of specimens collected. For example, it is unclear whether Key

Largo represented a “central hotspot,” a spot simply heavily visited by lepidopterists, or both (Saarinen 2009, p. 47). Still, it is clear that specimens were common in museum collections from the early 1900s to the 1980s, suggesting that the butterfly was abundant, at least in local patches, during this time period (Saarinen 2009, p. 46). This is consistent with the work of Carroll and Loye (2006, pp. 15-18), who, in a compilation of location data for specimens (N = 209), found that most collections were from the Upper Keys; those from peripheral sites were generally less recent and only single specimens. Examination of museum records further verified the Miami blue's wide distribution in southern Florida through time (Carroll and Loye 2006, pp. 15-18; Saarinen 2009, p. 46).

By the 1990s, very few Miami blue populations were known to persist, and the butterfly had not been seen on the western Florida coast since 1990, where it was last recorded on Sanibel Island (Calhoun
et al.
2002, p. 17). One of the few verifiable reports (prior to rediscovery in 1999) was on Big Pine Key in March 1992 (Glassberg
et al.
2000, p. 79; Glassberg and Salvato 2000, p. 1; Calhoun
et al.
2002, p. 17). Following Hurricane Andrew in 1992, there were a few unsupported reports from Key Largo and Big Pine Key and the southeastern Florida mainland from approximately 1993 to 1998 (Glassberg and Salvato 2000, p. 3; Calhoun
et al.
2002, p. 17). In 1996, four adult Miami blues were observed in the area of Dagny Johnson Key Largo Hammock Botanical State Park (DJSP) by Linda and Byrum Cooper (L. Cooper, listowner of LEPSrUS Web site, pers. comm. 2002; Calhoun
et al.
2002, p. 17). However, a habitat restoration project apparently eradicated that population (L. Cooper, pers. comm. as cited in Calhoun
et al.
2002, p. 17).

The Miami blue was presumed to be extirpated until its rediscovery in 1999 by Jane Ruffin, who observed approximately 50 individuals at a site in the lower Keys (Bahia Honda) (Ruffin and Glassberg 2000, p. 3; Calhoun
et al.
2002, p. 17). Additional individuals were located at a site within 0.5 mile (mi) (0.8 kilometers (km)) of where Ruffin had discovered the population (Glassberg and Salvato 2000, p. 3). Glassberg and Salvato (2000, p. 1) stated that more than 15 highly competent butterfly enthusiasts had failed to find any populations of the Miami blue from 1992 until 1999, despite more than 1,000 hours of search effort in all sites known to harbor former colonies and other potential sites throughout south Florida and the Keys. In May 2001, there was an additional sighting by Richard Gillmore of a single Miami blue in the hammocks in North Key Largo (Calhoun
et al.
2002, p. 17; J. Calhoun, pers. comm. 2003b).

Current Distribution

Numerous searches for the Miami blue have occurred in the past decade by various parties. The Miami blue was not observed on 105 survey dates at 11 locations on the southern Florida mainland from 1990 to 2002 (Edwards and Glassberg 2002, p. 4). In the Keys, surveys during the same time period also produced no sightings of the Miami blue at 29 locations for 224 survey dates (Edwards and Glassberg 2002, p. 4). In 2002, the Service initiated a status survey, contracting researchers at the UF, to search areas within the subspecies' historical range, concentrating on the extreme south Florida mainland and throughout the Keys. Despite surveys at 45 sites during 2002-2003, adults or immature stages were found only at a single site near BHSP on West Summerland Key (Emmel and Daniels 2004, pp. 3-6; 21-25) (approximately 1.9 mi [3 km]) west of BHSP). The Miami blue was not found on the mainland, including Fakahatchee Strand, Charles Deering Estate, ENP, Marco Island, or Chokoloskee (Emmel and Daniels 2004, pp. 5-6, 25). It was also absent from the following locations in the Keys: Elliott, Old Rhodes, Totten, and Adams Key in Biscayne National Park (BNP) and Key Largo and Plantation Key in the Upper Keys; Lignumvitae, Lower Matecumbe, Indian, and Long Keys in the Middle Keys; and Little Duck, Missouri, Ohio, No Name, Big Pine, Ramrod, Little Torch, Wahoo, Cudjoe, Sugarloaf, and Stock Island in the Lower Keys (Emmel and Daniels 2004, pp. 3-5; 21-24).

Based upon an additional independent survey in 2002, the Miami blue was also not found at 18 historical locations where it had previously been observed or collected in Monroe, Broward, Miami-Dade, and Collier Counties into the 1980s (D. Fine, unpub. data, pers. comm. 2002). These were: Cactus Hammock (Big Pine Key), County Road (Big Pine Key), Grassy Key, John Pennekamp Coral Reef State Park (Key Largo), Windley Key, Crawl Key, Stock Island, Plantation Key, and Lower Matecumbe Key in Monroe County; Hugh Taylor Birch State Park and Coral Springs (2 locations) in Broward County; Redlands, Frog City, Card Sound Road, and an unidentified road in Miami-Dade County; and Marco Island and Fakahatchee Strand State Preserve in Collier County.

In 2003, the Service contracted the North American Butterfly Association (NABA) to perform systematic surveys in south Florida and the Keys to identify all sites at which 21 targeted butterflies, including the Miami blue, could be found. Despite considerable survey effort (
i.e.,
187 surveys performed), the Miami blue was not located at any location except BHSP (NABA 2005, pp. 1-7). In addition, the Miami blue was not present within the J.N. Ding Darling National Wildlife Refuge or on Sanibel-Captiva Conservation Foundation properties (both on Sanibel Island), during annual surveys conducted from 1998 to 2009 (M. Salvato, pers. comm. 2011a). Monthly or quarterly surveys of Big Pine Key, conducted from 1997 to 2010, failed to locate Miami blues (M. Salvato, pers. comm. 2011b). Minno and Minno (2009, pp. 77, 123-193) failed to locate the subspecies during butterfly surveys throughout the Keys conducted from August 2006 to July 2009.

Although two fourth-instar larvae were documented on West Summerland Key in November 2003, on unprotected land approximately 2.2 mi (3.6 km) west of BHSP (Emmel and Daniels 2004, pp. 3, 24, 26), none have been seen there since. According to Daniels (pers. comm. 2003c), an adult (or adults) was likely blown to this key from BHSP by strong winds or was at least partially assisted by the wind.

In November 2006, Miami blues were discovered on islands within KWNWR (Cannon
et al.
2007, p. 2). This discovery was significant because it was a new, geographically separate population, and doubled the known number of metapopulations remaining (to 2). During the period from 1999 to 2009, the Miami blue was consistently found at BHSP (Ruffin and Glassberg 2000, p. 29; Edwards and Glassberg 2002, p. 9; Emmel and Daniels 2009, p. 4; Daniels 2009, p. 3). However, this population may now be extirpated. Thus, islands of KWNWR appear to support the only known extant population.

Overall, the Miami blue has undergone a substantial reduction in its historical range, with an estimated >99 percent decline in area occupied (Florida Fish and Wildlife Conservation Commission [FWC] 2010, p. 11). In 2009, metapopulations existed at two main locations: BHSP and KWNWR, roughly 50 mi (80 km) apart. The metapopulation at BHSP is now possibly extirpated with the last adult documented in July 2010 (A. Edwards, Florida Atlantic University, pers. comm. 2011). It is feasible that additional occurrences exist in the Keys, but these may be ephemeral and low in

population number (Saarinen 2009, p. 143). In 2010, the Service funded an additional study with UF to search remote areas for possible presence; this study has not identified any new populations. The subspecies was not located in limited surveys conducted in the Cape Sable area of ENP in March 2011 (P. Halupa, pers. obs. 2011; M. Minno, pers. comm. 2011a) nor December 2011 (J. Daniels, pers. comm. 2011).

Bahia Honda State Park

BHSP is a small island at the east end of the lower Keys, approximately 7.0 mi (11.3 km) west of Vaca Key (Marathon) and 2.0 mi (3.2 km) east of Big Pine Key. The amount of suitable habitat (habitat supporting larval host plants and adjacent adult nectar sources) within BHSP is approximately 1.5 acres (ac) (0.6 hectares [ha]). Of the suitable habitat available at BHSP, approximately 85 percent (1.3 ac [0.5 ha]) was occupied by the Miami blue (Emmel and Daniels 2004, p. 12). The metapopulation comprised 13 distinct colonies, with the core comprising 3 or 4 colonies, located at the southwestern end (Emmel and Daniels 2004, pp. 6, 27). This area contained the largest contiguous patch of host plants, although the size was estimated to be 0.8 ac (0.32 ha) (Emmel and Daniels 2004, p. 12). The second largest colony occurred at the opposite (northeast) end of BHSP and was based solely on the presence of two to three small, isolated patches of nickerbean directly adjacent to an existing nature trail and parking area (Emmel and Daniels 2004, p. 6). The remaining colonies were isolated, with most occurring in close proximity to the main park road (Emmel and Daniels 2004, pp. 13, 27). Isolated colonies used very small patches of nickerbean (
e.g.,
one was estimated to be 10 by 10 feet [3 by 3 meters]) (Emmel and Daniels 2003, p. 3), often adjacent to paved roads (Emmel and Daniels 2004, pp. 6, 12, 27).

Key West National Wildlife Refuge

Efforts to define the limits of the KWNWR metapopulation were conducted from November 2006 to July 2007 (Cannon
et al.
2007, pp. 10-11; 2010, p. 849). Miami blues were found at seven sites on five islands in the Marquesas Keys, approximately 18 to 23 mi (29 to 37 km) west of Key West, and on Boca Grande Key, approximately 12 mi (19 km) west of Key West (Cannon
et al.
2007, pp. 1-24; 2010, pp. 847-848). The eight sites occupied by Miami blues ranged from approximately 0.25 to 37.10 ac (0.1-15.0 ha) (Cannon
et al.
2007, p. 6; 2010, p. 848). The combined amount of upland habitat of occupied sites (within KWNWR) was roughly 59 ac (23.8 ha) (Cannon
et al.
2010, p. 848). Miami blues were not found on Woman Key, approximately 10.1 mi (16.2 km) west of Key West, or Man Key, approximately 6.8 mi (10.9 km) west of Key West; these sites had abundant nectar plants, but few host plants (Cannon
et al.
2007, pp. 5, 12; 2010, pp. 848-850). In addition, the Miami blue was not found on six islands in the Great White Heron National Wildlife Refuge (GWHNWR); these sites contained limited amounts of, or were lacking, either host plants or nectar plants (Cannon
et al.
2007, pp. 5, 12; 2010, pp. 847, 850-851).

In a separate study, Daniels also found four of the sites previously occupied within KWNWR to support the Miami blue variously from 2008 to 2010 (Emmel and Daniels 2008, pp. 7-10; 2009, pp. 9-13; Daniels 2008, pp. 1-6; Daniels 2010, pp. 3-5; J. Daniels, pers. comm. 2010a). Survey effort, however, was limited. Some previously occupied islands were not searched, and no new occupied areas were identified.

Followup presence and absence surveys by KWNWR in 2009 showed that the Miami blue was present on two sites in the Marquesas, but not on Boca Grande (P. Cannon, pers. comm. 2010a). In 2010, similar surveys indicated that the Miami blue was present on Boca Grande and one site in the Marquesas; it was still not located on Woman Key (P. Cannon, pers. comm. 2010b; T. Wilmers, pers. comm. 2010a). In March and April 2011, Miami blues were still present on five of seven sites where previously found in KWNWR (T. Wilmers pers. comm. 2011a; Haddad and Wilson 2011, p. 2).

Reintroductions

Although Miami blue butterflies were successfully reared in captivity, reintroductions have been unsuccessful. Since 2004, approximately 7,140 individuals have been released (J. Daniels, pers. comm. as cited in FWC 2010, p. 8). Initially, larvae were released in the vicinity of Flamingo at multiple locations within ENP (J. Daniels, pers. comm. 2012). Between August 2007 and November 2008, reintroduction events were carried out at BNP and DJSP 12 times resulting in the release of 3,553 individuals (276 adults/3,277 larvae) (Emmel and Daniels 2009, p. 4). Monitoring efforts have been limited; 19 days were spent monitoring reintroduction sites (Emmel and Daniels 2009, p. 4). To date, no evidence of colony establishment has been found (Emmel and Daniels 2009, p. 4). It is not clear why reintroductions were unsuccessful. Numerous factors may have been involved (
e.g.,
predation, parasitism, insufficient host plant or larval sources). Due to limited resources and other constraints, standard protocols were not employed to help identify factors that may have influenced reintroduction success. Research with surrogate species may be helpful to better establish protocols and refine techniques for the Miami blue prior to future propagation and reintroduction efforts.

Population Estimates and Status

Bahia Honda State Park Metapopulation

Prior to its apparent extirpation, the metapopulation at BHSP was monitored regularly from 2002 to 2009 (Emmel and Daniels 2009, p. 4). Pollard transects (fixed-route transects walked weekly under favorable weather conditions) at the south-end colony site (largest) yielded annual peak counts of approximately 175, 84, 112, and 132, from 2002 to 2005 (prior to hurricanes), and 82, 81, 120, and 38, from 2006 to 2009 (Emmel and Daniels 2009, p. 4). From October 2002 to September 2003, abundance estimates using mark-release-recapture (Schnabel method) ranged from a low of 19.7 in February 2003 to a high of 114.5 in June 2003 (Emmel and Daniels 2004, p. 9).

Counts ranged from 6 to 100 adults during surveys by the NABA, conducted from February 2004 to January 2005 (NABA 2005, unpub. data). Monthly (2003 to 2006) or bimonthly (2007) monitoring by Salvato (pers. comm. 2011c) at the south-end colony produced annual average counts of 129, 58, 46, 6, and 8, respectively, from 2003 to 2007. Salvato (pers. comm. 2011c) observed 21, 10, and 0 Miami blues from 2008 to 2010, respectively, based on limited surveys.

Due to the differences in methodologies and other factors, the above estimates cannot be compared. Although abundance of select butterflies may change frequently, their overall geographic distribution from year-to-year is often more consistent. Given that the Miami blue has overlapping generations and, at times, capacity for explosive growth, it may be useful to report population status in terms of occupied habitat, as has been done for other butterflies (Longcore
et al.
2010, pp. 335-346; T. Longcore,
in litt.
2011).

In general, early (dry) season numbers were low in most years and were attributed to a persistent south Florida drought (Emmel and Daniels 2009, p. 4). Abundance trends indicated that there was a marked decrease in the number of

individuals during the winter months (November to February) (Emmel and Daniels 2004, p. 9; 2009, p. 4). Higher abundances during the summer wet season may relate to production of a large quantity of new terminal growth on the larval host plants (nickerbean) and availability of nectar sources from spring rainfall (Emmel and Daniels 2004, pp. 9-11).

Four hurricanes affected habitat at BHSP in 2005, resulting in reduced abundance of Miami blue following subsequent storms that continued throughout 2006 (Salvato and Salvato 2007, p. 160). Although no quantitative measurements were taken, a significant portion of the nickerbean in the survey area (> 35 percent of the area of available habitat) was damaged by the storms; roughly 60-80 percent of the vegetation on the southern side of the island was visually estimated to have been heavily damaged, including large stands of host and nectar plants (Salvato and Salvato 2007, p. 156). Despite a decline in abundance after the hurricanes, the Miami blue had appeared to rebound toward pre-storm abundance by the summer months of 2007 (Salvato and Salvato 2007, p. 160). However, peaks remained below those found prior to the 2005 hurricane season (Emmel and Daniels 2009, p. 4).

Although it is unclear when iguanas became established at BHSP, effects of herbivory on the host plant were apparent by late 2008 or early 2009 (Emmel and Daniels 2009, p. 4; Daniels 2009, p. 5; P. Cannon, pers. comm. 2009; A. Edwards, pers. comm. 2009; P. Hughes, pers. comm. 2009; M. Salvato, pers. comm. 2010a). Defoliation was mostly limited to the south-end colony site (Emmel and Daniels 2009, p. 4). Cooperative eradication efforts to address this problem began in 2009 and continue today; however, iguanas continue to impact terminal nickerbean growth (see
Summary of Factors Affecting the Species
) (Emmel and Daniels 2009, p. 4; Daniels 2009, p. 5; E. Kiefer, BHSP, pers. comm. 2011a). From 2006 through 2009, adult or immature Miami blues were found at several colony sites; however, one colony became relatively unproductive in 2005 (pre-hurricane) (Emmel and Daniels 2009, p. 4). No Miami blues have been found at any roadway nickerbean patches within BHSP since 2005, prior to the advent of profound iguana herbivory and damages from hurricanes (Emmel and Daniels 2009, p. 4).

The metapopulation has diminished in recent years likely due to the combined effects of small population size, drought, cold temperatures, and iguanas (see
Summary of Factors Affecting the Species
). In 2010, few Miami blues were observed at BHSP. On January 23, 2010, a photograph was taken of a pair of Miami blues mating (Olle 2010, p. 5). On February 12, 2010, a photograph was taken of a single adult (C. DeWitt, pers. comm. 2011). In March 2010, Daniels found one larva, but no adults (D. Cook, FWC, pers. comm. 2010a). In July 2010, a single adult was observed and photographed (A. Edwards, pers. comm. 2011). No Miami blue adults have been located during quarterly surveys conducted in 2010 by Salvato (pers. comm. 2010b, 2011c). No Miami blue butterflies of any life stage were subsequently seen despite frequent searches (D. Cook, pers. comm. 2010a; P. Cannon, pers. comm. 2010c, 2010d, 2010e, 2010f; M. Salvato, pers. comm. 2011c, 2011d; Jim Duquesnel, BHSP, pers. comm. 2011a, 2011b).

Key West National Wildlife Refuge Metapopulation(s)

The metapopulation at KWNWR yielded counts of several hundred, at various times, in 2006-2007. Checklist counting, a method where suitable habitat is initially screened to determine the presence of target species, was used during surveys conducted between November 2006 and July 2007 to document the distribution and abundance of Miami blues (Cannon
et al.
2007, p. 5; 2010, p. 848). Within the seven sites occupied in the Marquesas Keys, the highest counts ranged from 8 to 521, depending upon site and sampling date (Cannon
et al.
2007, p. 7; 2010, p. 848). The highest count on Boca Grande was 441 in February 2007 (Cannon
et al.
2007, p. 7; 2010, p. 848). Highest counts occurred when blackbead flowered profusely and produced new leaves (Cannon
et al.
2010, p. 851). In March and April, blackbead was observed to yield little new growth and no flowering, and oviposition by Miami blues was not observed (Cannon
et al.
2007, p. 8). Partial searches on two islands in May and June revealed few Miami blues; little new leaf growth and no flowering of blackbead was observed at these locations after February 2007 (Cannon
et al.
2010, p. 850). Seasonality observed on KWNWR was different than that described for the BHSP metapopulation (above). Hurricane Wilma (October 2005) heavily damaged or killed blackbead stands at most sites, but it also likely enhanced foraging habitat, if only temporarily, on select islands within the KWNWR (Cannon
et al.
2007, p. 10; 2010, p. 851) (see
Summary of Factors Affecting the Species
).

Periodic surveys at KWNWR in 2008 and 2009 suggested relatively lower levels of abundance, based upon limited effort (Emmel and Daniels 2008, pp. 7-10; 2009, pp. 9-13) and using different methodologies. In February 2008, researchers recorded 3 adults on Boca Grande and a total of 32 adults at two islands within the Marquesas; lack of rainfall resulted in very limited adult nectar sources and limited new growth of larval host plants (Emmel and Daniels 2008, pp. 7-8). In April 2008, one adult was recorded on Boca Grande; one adult was also recorded at another island (Emmel and Daniels 2008, p. 8). In June 2008, no adults were located on Boca Grande, and a total of 27 were recorded from two other islands (Emmel and Daniels 2008, p. 9). In August 2008, no adults were found at Boca Grande, and five adults were recorded at another island (Emmel and Daniels 2008, p. 10). In March 2009, no adults were recorded on Boca Grande; habitat conditions were deemed very poor, with limited new host growth and available nectar resources (Emmel and Daniels 2009, p. 12). In April 2009, researchers found a total of 22 adults from 2 islands within the Marquesas (Emmel and Daniels 2009, p. 13).

Based upon limited data and observations, the Miami blue persisted on various islands within the KWNWR in 2010. From April through July 2010, the Miami blue was observed on 5 of 10 dates at one location within the Marquesas, although in limited numbers during brief surveys (T. Wilmers, pers. comm. 2010b). On July 28, 2010, researchers recorded 19 adults from 3 islands within the Marquesas, in limited surveys; another 25 adults were recorded on Boca Grande in less than 1 hour of survey work (J. Daniels, pers. comm. 2010a). On September 30, 2010, dozens of Miami blues were observed on Boca Grande; this may have represented an actual population size in the hundreds (N. Haddad, North Carolina State University [NCSU]), pers. comm. 2010). On November 24, 2010, researchers positively identified 48 Miami blue adults on Boca Grande in less than 3 hours of surveys, noting that assessment was difficult due to the many hundreds or possibly thousands of cassius blues, which were also present (P. Cannon, pers. comm. 2010b; T. Wilmers, pers. comm. 2010a). In March and April 2011, researchers observed Miami blue adults at five sites within KWNWR in numbers similar to those reported above (Haddad and Wilson 2011, p. 2). In July 2011, fewer adults were observed (P. Hughes, pers. comm. 2011a). In September 2011,

Refuge staff observed 14 adults on Boca Grande (P. Hughes, pers. comm. 2011b). In December 2011, 88 adults were found in roughly 4 hours (P. Cannon, pers. comm. 2012). In January 2012, Refuge staff observed 20 adults on Boca Grande and 14 adults at one site in the Marquesas during brief surveys under windy conditions (A. Morkill, pers. comm. 2012).

At this time, both the size of the metapopulation at KWNWR and its dynamics are unclear. However, available data (given above) suggest wide fluctuations of adults within and between years and sites. The frequency of dispersal between islands is also not known (Cannon
et al.
2010, p. 852). Due to the distance between the Marquesas and Boca Grande (
i.e.,
about 7 mi [11 km]) and the species' apparent limited dispersal capabilities, it is possible that two (or more) distinct metapopulations exist within KWNWR (J. Daniels, pers. comm. 2010b). In September 2010, the Service initiated a new study with researchers from NCSU to conduct a comprehensive examination of potential habitat within KWNWR and GWHNWR, quantify current distribution and habitat use, and develop a monitoring protocol to estimate detectability, abundance, and occupancy parameters.

Gene Flow and Genetic Diversity Within Contemporary Populations

Saarinen (2009, pp. 15, 29-33, 40, 44) and Saarinen
et al.
(2009b, pp. 242-244) examined 12 polymorphic microsatellite loci (noncoding regions of chromosomes) to assess molecular diversity and gene flow of wild and captive-reared Miami blue butterflies. In addition, one of these microsatellite loci was successfully amplified from a subset of the museum specimens. Although results from historical specimens should be interpreted with caution (due both to small sample size and the single microsatellite locus), Saarinen (2009, pp. 15, 50-51) reported some loss of diversity in the contemporary populations, though less than had been expected. Even with small sample sizes, historical populations were significantly more diverse (with generally higher effective numbers of alleles and observed levels of heterozygosity) than BHSP; KWNWR population values were between historical values and BHSP values (Saarinen 2009, pp. 44-46).

Both historical and contemporary populations showed evidence of a metapopulation structure with interacting subcolonies (E.V. Saarinen and J.C. Daniels, unpub. data as cited in Saarinen 2009, p. 49). However, the metapopulations at BHSP and KWNWR are separated by a distance of more than 43 mi (70 km). Given the Miami blue's dispersal capabilities (E.V. Saarinen and J.C. Daniels, unpub. data as cited in Saarinen 2009, p. 22), it is unlikely that they interacted. Saarinen's work showed no gene flow and a clear distinction between the BHSP and KWNWR metapopulations (Saarinen 2009, pp. 36, 74, 89) (see
Summary of Factors Affecting the Species
).

Studies addressing molecular diversity at BHSP showed the effective number of alleles remained relatively constant over time, at both a monthly (generational) and annual scale (Saarinen 2009, pp. 71, 84). Allelic (gene) richness was also stable over time in BHSP, with values ranging from 2.988 to 3.121, when averaged across the 12 microsatellite loci from September 2005 to October 2006. These values were lower than those in KWNWR [3.790] (Saarinen 2009, p. 71). However, data showed that the BHSP metapopulation retained an adequate amount of genetic diversity to maintain the population in 2005 and 2006, despite perceived changes in overall population size (Saarinen 2009, p. 77). No significant evidence of a recent genetic bottleneck was found in the BHSP generations analyzed; however, there may have been a previous bottleneck that was undetectable with the methods used (Saarinen 2009, pp. 72, 85, 141).

To explore the level of gene flow and connectivity between discrete habitat patches at BHSP, Saarinen (2009, pp. 64-65) conducted analyses at several spatial scales, analyzing BHSP as a single population (with no subdivision), as individual colonies occupying discrete habitat patches (as several groups acting in a metapopulation structure), and as a division of clumped colonies versus other, more spatially distant colonies. Analyses of microsatellite frequencies were also used to assess gene flow between habitat patches (Saarinen 2009, p. 72). While some subpopulations were well linked, others showed more division (Saarinen 2009, p. 73). High levels of gene flow (and relatively little differentiation) were apparent even between distant habitat patches on BHSP, and the smaller patches appeared to be important links in maintaining connectivity (Saarinen 2009, pp. 78, 141). Overall, gene flow between habitat patches on BHSP was considered crucial to maintaining genetic diversity and imperative for the Miami blue's long-term persistence at this location (Saarinen 2009, p. 141).

The metapopulation structure on KWNWR is more extensive than that which occurred at BHSP (Saarinen 2009, p. 49). Due to small sample sizes from Boca Grande, only samples from the Marquesas Keys were used for genetic analysis of KWNWR, and results were limited (Saarinen 2009, pp. 66, 72). Overall, this metapopulation was found to have higher genetic diversity (mean observed heterozygosity of 51 percent versus 39.5 percent) than the BHSP population (Saarinen 2009, p. 49). Allelic richness (3.790 in February 2008) was also higher in KWNWR (Saarinen 2009, pp. 71, 75). Accordingly, KWNWR is a particularly important source of variation to be considered for future conservation efforts for this taxon (Saarinen 2009, pp. 71, 75), especially now if this is the only extant metapopulation(s) remaining. The KWNWR metapopulation showed signs of a bottleneck and may support the hypothesis that it is a newly founded population (Saarinen 2009, pp. 76, 141). Further work is needed to better understand the metapopulation dynamics and genetic implications in this population.

Summary of Comments and Recommendations

In the proposed rule published on August 10, 2011 (76 FR 49408), we requested that all interested parties submit written comments on the proposal by October 11, 2011. We also contacted appropriate Federal and State agencies, scientific experts and organizations, and other interested parties and invited them to comment on the proposal. Newspaper notices inviting general public comment were published in The Miami Herald, Orlando Sentinel, Tampa Tribune, The Daytona Beach News-Journal, and the Key West Citizen on Sunday, August 21, 2011. We did not receive any requests for a public hearing.

During the comment period for the proposed rule, we received 37 comment letters (from 35 entities) directly addressing the proposed listing of the Miami blue butterfly with endangered status and the proposed listing of the cassius blue, ceraunus blue, and nickerbean blue butterflies as threatened under similarity of appearance. With regard to listing the Miami blue butterfly as endangered, 25 comments were in support, 2 were in opposition, and 10 were neutral. With regard to listing the other 3 butterflies under similarity of appearance, 4 comments were in support, and 16 comments were in opposition. Of those comments in opposition, six suggested alternatives that were more limited in scope (
e.g.,
applying similarity of appearance provisions to the Miami blue's current

or historical range). All substantive information provided during the comment period has either been incorporated directly into this final determination or addressed below.

Peer Review

In accordance with our peer review policy published on July 1, 1994 (59 FR 34270), we solicited expert opinion from 14 individuals with specialties that include scientific expertise with butterflies, particularly lycaenids, and general expertise with ecology and conservation. We received independent responses from eight of the peer reviewers. We also received two collaborative responses from State governmental agencies, which had been solicited as part of this process. We address these under
Comments from the State.

We reviewed all comments received from peer reviewers for substantive and new information regarding the listing of the Miami blue butterfly as endangered and the cassius blue, ceraunus blue, and nickerbean blue butterflies as threatened under similarity of appearance. The peer reviewers concurred with the conclusion to list the Miami blue butterfly as endangered and provided additional information, clarifications, and suggestions to improve the final rule. In general, the majority of peer reviewers opposed Federal listing of the three other butterflies due to similarity of appearance; however, one reviewer agreed with the original proposal, and three suggested applying the similarity of appearance listing only to select areas where the butterflies may co-occur with the Miami blue.

Peer Reviewer Comments

(1)
Comment:
One peer reviewer indicated that the Miami blue butterfly should remain in the genus
Hemiargus,
as originally described, citing Comstock and Huntington (1943), Nabokov (1945), and Vila
et al.
(2011) as relevant taxonomic papers. The reviewer noted that only limited phylogenetic analyses have been conducted to determine if the genus
Hemiargus
should be split into a variety of additional genera, such as
Cyclargus.
In his view, the Miami blue is well characterized and easily recognized, but should continue to be treated as
Hemiargus thomasi bethunebakeri
and listed as such, rather than
Cyclargus thomasi bethunebakeri.

Our Response:
We acknowledge that some sources continue to place the Miami blue in the genus
Hemiargus.
However, our basis for using
Cyclargus
is founded on published and unpublished literature, separate confirmation of specimens from independent taxonomists or reviewers, and other accepted taxonomic sources (see
Taxonomy
). We note that several Web sites (
e.g., Butterflies of America,

Catalog of the Butterflies of the United States and Canada,
and the
Integrated Taxonomic Information System),
widely regarded as definitive sources, also continue to place the Miami blue as
Cyclargus thomasi bethunebakeri.
We determined that this is the most appropriate nomenclature because it is more widely accepted by the scientific community. Therefore, we have used the genus
Cyclargus
in this final rule.

(2)
Comment:
Two peer reviewers and five commenters expressed concern over the Service's determination that critical habitat is not prudent, disagreed with this decision, or otherwise suggested that we reconsider this determination. Two commenters supported our determination. Comments in opposition to our not prudent determination were largely based on the potential benefits of designating critical habitat and skepticism that increased risk and harm to the Miami blue would occur with designation, as ample detail is already available for poachers to locate remaining populations.

Our Response:
We determined that designating critical habitat for the Miami blue is not prudent. We recognize that designation of critical habitat can provide benefits to listed species (see
Benefits to the Subspecies From Critical Habitat Designation,
below, as well as discussion later in this response); however, for the Miami blue, increased threats (see
Increased Threat to the Subspecies by Designating Critical Habitat,
below) outweigh the benefits (see
Increased Threat to the Subspecies Outweighs the Benefits of Critical Habitat Designation,
below).

We do not dispute the arguments of the two peer reviewers and some commenters who suggested that industrious or unethical collectors have enough information to be able to locate the remaining populations. We acknowledge that general location information is provided within the rule, and more specific location information can be found through other sources. However, we maintain that designation of critical habitat would more widely publicize the potential locations of the butterfly and its essential habitat to poachers, collectors, vandals, and mischievous individuals, thereby exacerbating the already significant threats of collection, vandalism, disturbance, fire, and other harm from humans.

One commenter, who agreed with our decision that designating critical habitat is not prudent, provided additional references (Hoekwater 1997, Kleiner 1995, O'Neill 2007) showing that individuals poach rare and imperiled taxa for profit, even to the point of driving a species to extinction in order to increase the value of individual specimens (Laufer 2009). We want to stress that our reasons for not designating critical habitat go beyond the potential increased threat of collection, but also involve potential associated increased risks to sensitive and important habitats (see also
Inadvertent and Purposeful Impacts From Humans,
below). Designation of unoccupied habitat could also alienate any affected private landowners and stakeholders, thus limiting reintroduction and recovery options (see also Response to Comment #24 below).

We agree that designation of critical habitat can provide some benefits to listed species (
e.g.,
a tool to restore and manage habitat on Federal lands, greater awareness and education by the public, increased cooperation by other agencies to improve habitat). With the Miami blue, substantial efforts at education and active conservation efforts from Federal, State, and local agencies are already underway, so potential added benefits from designation would likely be minimal.

(3)
Comment:
One peer reviewer stated that the status of the Miami blue is grave and that extinction is a distinct possibility. Another peer reviewer stated that the Miami blue has an extremely high likelihood of becoming extinct unless active conservation measures are applied immediately.

One commenter indicated that the Miami blue is one of the rarest butterflies in the United States and in the world. The commenter specifically stated that it may be the single rarest butterfly species, and is rarer than at least 14 species that are listed under the Act. He indicated that understanding spatial and population structure and dispersal are keys to recovery, as are restoration and reintroduction. Another commenter, certified by the International Union for the Conservation of Nature to evaluate extinction risk, stated that the Miami blue meets all five criteria for listing under the Act. Another commenter urged immediate action to address threats and the development of a “functional” recovery plan, with the assistance of experts. Another commenter encouraged the Service to take all possible steps to recover the subspecies, stressing the importance of future reintroductions in the best possible habitats.

Our Response:
We agree. The threats to the Miami blue pose a significant risk

to the subspecies and were the basis of our emergency determination, which immediately put forth conservation measures (see
Available Conservation Measures,
below). We are actively working with stakeholders and partners to implement additional conservation actions now to prevent extinction. We fully intend to actively engage others and implement actions that will help ensure survival and long-term recovery. We will work closely with scientific experts, land managers, stakeholders, and others to ensure that any future captive propagation and reintroduction efforts do not harm the wild population, and occur in optimal habitat to increase the likelihood of persistence.

(4)
Comment:
One peer reviewer stated that the largest threat to the Miami blue is the small size of the single remaining metapopulation. He contended that, if the subspecies is to survive, the priority needs to be on improving the quality of existing habitats, enlarging breeding areas, and creating new breeding habitats, if possible. One commenter estimated numbers at the peak of the Miami blue's flight period in the hundreds, stating that conservation biologists agree that numbers should be many thousands to counteract the negative effects of inbreeding, genetic drift, and environmental catastrophes. This commenter also stated the small area currently occupied is “frighteningly small” and that additional and more widespread sites are needed to provide insurance against the extinction of a localized population. This reviewer and other commenters believed that reestablishment at other locations is a priority because of the substantial risk of extinction due to stochastic events and other threats.

Our Response:
We agree that several of the most important threats to the Miami blue are currently small population size, few populations, and restricted range. We concur that the actions specified are needed and acknowledge that other actions to reduce threats are also needed for survival and recovery (see
Determination of Status,
below).

(5)
Comment:
One peer reviewer suggested that poaching is a more accurate term than collection. This reviewer viewed poaching as a potential threat to the Miami blue and indicated that to spend “two full pages discussing hypothetical threats sounds biased” in his view. One commenter stated that the Miami blue has no protection from poachers and suggested that listing may invite poachers to offshore islands. She indicated that she has been contacted by someone interested in acquiring rare butterflies. Another commenter noted that listing would call additional attention from commercial traders to the Miami blue and related species.

Our Response:
We provided a thorough and detailed description of the threat posed by collection in the proposed rule. In addition, we believe that it is necessary to fully discuss the many activities that go beyond collection, and include other illegal and illicit activities. Because we do not have evidence of collection of the Miami blue, we outline illegal and illicit activities involving other listed or imperiled butterflies on various protected lands and the established markets for specimens. We have determined that poaching is a potential and significant threat that could occur at any time, but poaching is only a subset of the activities that threaten the Miami blue. The generic term “collection” is more easily understood by the public and better encompasses the breadth of activities related to this threat.

We recognize that listing may inadvertently increase the threat of collection and trade (
i.e.,
raise value, create demand). However, we have determined, based upon the best available scientific information, that the subspecies meets the criteria for Federal protection. Accordingly, it is our obligation to take protective action through Federal listing to help safeguard the subspecies.

(6)
Comment:
Two peer reviewers indicated that a better understanding of host plants will be essential for effective Miami blue conservation. One noted that there is considerable ambiguity as to the breadth of host plant use and plant-herbivore interactions. Another peer reviewer noted the general preference of the Palos Verdes blue butterfly for fresh growth on host plants (citing Johnson
et al.
2011). This reviewer suggested that not all available host plant mass at a given location may be appropriate for use (larval and female egg-laying) and that the actual available suitable host plant may be far less than the total mass at any given site. One commenter suggested that no natural populations of the Miami blue are known to feed on balloonvine, despite its availability. Another commenter noted that the Miami blue was originally associated with balloonvine, but subsequently adapted to using gray nickerbean due to efforts to control balloonvine.

Our Response:
We agree that further studies into historical and current Miami blue host plant preferences are essential to best conserve and recover the subspecies. Available scientific literature documents a variety of host plants for the Miami blue (see—
Life History
and
Habitat
under Background, above). This is consistent with recent host plant use in contemporary Miami blue populations. The last Miami blues observed on northern Key Largo in 1996 fed on balloonvine; those at BHSP fed on nickerbean and blackbead; and those within KWNWR rely primarily on blackbead. We note that balloonvine was not reported as a host plant until the 1970s, and that host plant use appears to have changed through time depending upon availability (see
Habitat
for complete discussion). Balloonvine was likely only one of several legumes used by historical Miami blue populations.

We agree that not all available host plants at a given location may be appropriate for larval use and that actual available suitable host plant mass may be far less than the total present. This is consistent with findings from available research. For example, when the Miami blue occurred at BHSP, only a small portion of available habitat on the island appeared occupied, and higher abundances were found when there was a large quantity of new terminal growth of nickerbean and when more nectar sources were available (Emmel and Daniels 2004, pp. 9-12).

(7)
Comment:
One peer reviewer recommended several clarifications regarding the description of the Miami blue (wing-chord length) and aspects of its life history (four instars, not five).

Our Response:
We have replaced the term “wing-chord length” with the more frequently used measure of “forewing.” The term fifth-instar was a typographical error and has been corrected with fourth-instar. We also made other suggested minor clarifications. These changes are set forth in the Background section of this final rule.

(8)
Comment:
Two peer reviewers questioned the maximum adult life span of the Miami blue and how this was determined and suggested that adults likely live more than 9 days. These reviewers suggested that older individuals may be more likely to disperse and that finding them once dispersed may be difficult. One reviewer cited research showing that older females may be prone to longer movements (Bergman and Landin 2002, p. 361).

Our Response:
We agree that the maximum 9-day life span as discussed in the emergency rule is unclear and may be an underestimate of natural adult life span. We have clarified the text in this final rule accordingly. Additional field studies are needed to

better ascertain adult Miami blue longevity in the wild and to determine dispersal capabilities.

(9)
Comment:
Three peer reviewers and one commenter questioned the degree to which the Miami blue is sedentary, suggesting that it may be less sedentary than described. One reviewer suggested that the subspecies may be sedentary at certain stages of its life, but that the Miami blue's historical range (
i.e.,
central Florida to the Keys and Dry Tortugas) is evidence that it disperses over wide areas of water over long periods of time. Another suggested that it only takes a wayward gravid female to colonize a new habitat. Another suggested that a butterfly surviving in a metapopulation due to habitat structure such as the Miami blue must have stronger dispersal capabilities than described in the rule, at least in a small fraction of the population.

One commenter stated that, although the butterfly appears to be sedentary now, it once occurred widely in the Keys and coastal areas of central and southern Florida and that it is capable of dispersing and colonizing new areas, including islands.

Commenters suggested that keys to designing a recovery strategy include a clear focus on basic life history, population dynamics, and an improved understanding of dispersal. One commenter indicated that a well-informed recovery plan would include a strategy for multiple interconnected populations that buffer the subspecies when some localized populations are lost and that more information is needed about dispersal capacity.

Our Response:
We agree that the Miami blue may be less sedentary than described and have made clarifications to the text. At this time, it is unclear how far the butterfly can disperse and the mechanisms for dispersal (
i.e.,
active [flight] or passive [wind-assisted]). We acknowledge that wayward individuals and gravid females can colonize new areas. Clearly, additional study is needed to better understand the Miami blue's dispersal capabilities and mechanisms. We agree that improved understanding of basic life history and population dynamics, including dispersal, will be key components to an effective recovery strategy. An effective recovery strategy will likely provide for multiple, interconnected populations that enable genetic exchange and facilitate recolonization in the event of local extirpations.

(10)
Comment:
One peer reviewer indicated that diapause can be difficult to detect. He suggested that the Miami blue, like other closely related species, could enter diapause as third instars rather than as adults, in response to photoperiod, temperature, or changes in host plants.

Our Response:
We acknowledge that there is some uncertainty regarding diapause (see
Life History
). We believe that the Miami blue's life history requires further study in order to better determine if any life stages undergo a dormant period.

(11)
Comment:
One peer reviewer expressed his opposition of mark-recapture methods for lycaenids, particularly small blues, such as the Miami blue butterfly.

Our Response:
We acknowledge that not enough information is known about the influence of mark-recapture on butterflies and that it can be harmful, depending upon the species, techniques employed, skill of handlers, and other factors. There have been several studies of various mark-recapture techniques with conflicting results regarding the impact on butterflies. Recently, Haddad
et al.
(2008, p. 938) reviewed several types of monitoring techniques and suggested that mark-recapture is not appropriate for small and/or imperiled butterflies. Researchers are not employing mark-recapture techniques on the Miami blue at this time.

(12)
Comment:
One peer reviewer indicated that disturbance factors may be beneficial to the host plants and that conservationists have a tendency to remove disturbances from protected lands, which can work against species dependent upon early successional plants (citing Longcore and Osborne 2010 and Longcore
et al.
2010). One commenter indicated that trampling of host plants has occurred within KWNWR.

Our Response:
We agree that periodic natural disturbances may benefit the habitat, thereby increasing the vigor or distribution of important host plants. However, human-related disturbances (
e.g.,
vandalism, trampling, camping, fire pits) can present significant risk to the Miami blue (especially larval stages) and important stands of host plants (see
Inadvertent and Purposeful Impacts from Humans
). Given the butterfly's overall vulnerability to extinction, we acknowledge that it will be important to minimize human-related and other controllable threats, especially in areas of known occupied habitat. Reducing threats will help safeguard the subspecies and its habitat.

(13)
Comment:
One peer reviewer stressed the importance of ant associations among lycaenids and provided various examples and citations. This reviewer stated that he believed that carpenter ants,
Camponotus
spp., may be extremely important in the reintroduction and long-term survival of the Miami blue at specific locations and that successful establishment may be dependent upon presence of these ants. Another peer reviewer cited a new paper by Trager and Daniels (2011) on mating and egg production in the Miami blue, noting that incorporating that study into the background does not change the outcome or conclusions of the proposed and emergency rules. Two commenters also noted interactions (mutualistic, predatory) between the Miami blue and ants and suggested further investigation.

Our Response:
We agree that ant associations may be an important component of the Miami blue's life history and that further studies of ant and Miami blue larval interactions are needed. Studies focusing on remaining populations would be useful. However, it may also be helpful to examine ant-larval interactions using surrogate species at historical Miami blue locations (
e.g.,
BHSP or Key Largo) or in the laboratory. We have included information from the Trager and Daniels (2011) paper in the Background (see
Life History,
above) and agree that this paper does not alter the conclusions of our proposed and emergency rules. It also does not alter the conclusions of this final rule.

(14)
Comment:
One peer reviewer cautioned against comparisons of Pollard transect counts with mark-recapture abundance estimates, noting that these two different methods of estimating population size can be compared with similar methods but not necessarily with each other. This reviewer suggested that, because the Miami blue has overlapping generations and presumably the capacity for explosive growth, it might be more productive to report population status in terms of area occupied (citing Longcore
et al.
2010).

Our Response:
We agree. We understand that there are a variety of techniques to measure abundance and monitor butterfly populations and have clarified discussion of available data (see
Population Estimates and Status,
above). Researchers are currently refining methods and techniques to most effectively gauge population size within KWNWR, including seasonality, as part of an ongoing study the Service funded in 2010. Gauging overall status in terms of occupied habitat, as has been done for other butterflies, may be more meaningful (Longcore
et al.
2010, pp. 335-346; T. Longcore,
in litt.
2011).

(15)
Comment:
One peer reviewer noted that Clench only made one collecting trip to the West Indies (the

Bahamas before 1941) (see Clench 1941).

Our Response:
We have clarified the text in this final rule accordingly.

(16)
Comment:
One peer reviewer was concerned about a proposed project to develop a zip-line course at Crane Point in the City of Marathon and suggested that the Service work closely with the City to minimize potentially adverse impacts of such a development to the recovery of the Miami blue.

Our Response:
We were not aware of this particular project, but we are coordinating with agencies and partners regarding various development projects within Monroe County to avoid and minimize impacts to the Miami blue and other federally listed species. We will work closely with the City of Marathon and others on this potential project as well.

Comments Relating to Similarity of Appearance Butterflies

(17)
Comment:
Six peer reviewers and ten commenters opposed listing the other butterflies due to similarity of appearance, as proposed, for a variety of reasons. The proposed action was generally opposed because it was thought to be overly restrictive or not needed because the similar butterflies are common and can be readily differentiated from the Miami blue based upon clear morphological differences.

Some reviewers and commenters supported the listing of the similar butterflies as proposed. Other reviewers, commenters, and FWC suggested alternatives for application of the similarity of appearance provision of the Act. These alternatives consisted of limiting application to only areas where the butterflies are sympatric with the Miami blue (potential or occupied habitat), only within critical habitat (if designated), only within specified counties, or only within counties within the Miami blue's historical range.

Those in opposition generally believed that listing similar butterflies would impede research and discourage cooperation or scientific support for future listing actions. Several commenters indicated that it would negatively and needlessly impact collectors, hobbyists, and those who collect insects for educational purposes. One commenter stated that there should not be any restrictions on the sale, purchase, or gifts of legally obtained cassius, ceraunus, or nickerbean blue butterflies. One commenter warned that the “unnecessary ban on collection and commerce” of the three “similar” species could ultimately harm the butterflies by impeding research and future discoveries, and also harm the relationships between the Service and hobbyist collectors, researchers, and naturalists. The same commenter suggested that careful monitoring and patrolling of occupied and historical suitable sites may be a more effective protective measure than enforcing a ban on collection and commercial transactions involving these taxa at a state or national level.

Another commenter noted that the action was not necessary because those seeking to collect the Miami blue or similar species on protected conservation lands would theoretically already possess the necessary permits. Some commenters suggested that listing due to similarity of appearance was inconsistent with other butterfly listings that have similar species that more closely resemble each other and do not have similarity of appearance provisions.

Our Response:
We carefully considered all of the comments received and agree that prohibiting collection, possession, and trade of these similar butterflies throughout their national and international ranges could result in unnecessary restrictions and regulatory burdens. After careful review of the needs of the Miami blue and the potential impacts of the special 4(d) rule as originally proposed, we have reconsidered this aspect of the proposed rule and have made significant changes regarding its application. Consequently, in this final rule, only collection of these similar butterflies within the current and historical range of the Miami blue butterfly will be prohibited. See Summary of Changes from Proposed Rule, below, for more detail.

We maintain that the Miami blue, due to its small population size and few populations, faces a significant threat from collection, and that prohibiting collection of similar butterflies within the historical range of the Miami blue is in the best interest of the subspecies. We have determined that limiting application of the special 4(d) rule to only the act of collecting and only within the historical range of the Miami blue is sufficient to protect the subspecies from threats faced due to collection pressure on the three similar butterflies. The proposed restrictions on trade and commerce have been removed, thus eliminating unnecessary restrictions and reducing regulatory burdens for most potentially affected parties (
i.e.,
elsewhere in Florida, other countries). We value relationships and are committed to working cooperatively with stakeholders to relieve unnecessary burdens while safeguarding the subspecies.

With regard to concerns regarding research, studies can be conducted on the similarity of appearance butterflies in the vast majority of their ranges (
i.e.,
outside of Florida, outside of the affected counties in Florida). For research in south and central Florida, many scientific activities involving the similar butterflies will only need prior written authorization (
e.g.,
a letter) from the Service. See
Special Rule Under Section 4(d) of the Act
below for more information.

We agree that increased patrols and monitoring may be helpful in deterring collection of the Miami blue. However, due to limited resources, this may not be feasible.

We disagree with views that listing the other butterflies due to similarity of appearance is unnecessary because those seeking to collect the Miami blue or similar species on conservation lands would already possess the necessary permits. We are aware of cases where federally listed species have been collected from conservation lands illegally or without permits (see
Collection,
below) and acknowledge that listing may increase demand for specimens. We have determined that the similarity of appearance provisions will help deter potential collection of Miami blues (purposeful or inadvertent) in all areas within its historical range, including those areas that are not conserved or those in private ownership.

Finally, we acknowledge that similarity of appearance has not been previously applied to arthropods (including insects, such as butterflies) prior to this listing, but it is a tool available to us under the Act. Similarity of appearance protections can be effective in situations where collection is a primary threat and population sizes are extremely low, as in the case of the Miami blue butterfly. We have determined that a special rule listing the additional three butterflies is necessary in this instance to protect the subspecies from collection throughout its current and historical range.

(18)
Comment:
One peer reviewer indicated that, if listing creates demand for collectors, then listing of the other similarity of appearance butterflies will increase the likelihood of intentional or unintentional collection of the Miami blue. Another reviewer and a commenter suggested that listing would increase their values to collectors. Other reviewers and commenters believed that the issue of illegal collection of the Miami blue is unlikely to be deterred by listing the three additional co-occurring, common butterflies.

Our Response:
Although we agree that listing may create demand for some collectors, we find that prohibiting collection of the similarity of appearance butterflies within the Miami blue's historical range will help reduce the threat of collection for the Miami blue. Through this action, the public and all stakeholders will be aware that the collection of the Miami blue and other similar blue butterflies in coastal south and central Florida is prohibited and illegal.

(19)
Comment:
One peer reviewer questioned if the other similarity of appearance butterflies would remain listed should the Miami blue butterfly become extinct.

Our Response:
If the Miami blue becomes extinct, the similarity of appearance butterflies will remain listed until the Miami blue becomes delisted, or we deem that the similarity of appearance protections are no longer necessary. In either of these scenarios, the Service would need to have adequate scientific data suggesting these actions are warranted, and then proceed with the normal rulemaking process (
i.e.,
publish proposed and final rules in the
Federal Register
).

Comments From the State

Section 4(i) of the Act states, “the Secretary shall submit to the State agency a written justification for his failure to adopt regulations consistent with the agency's comments or petition.” Comments received from the State are addressed below.

(20)
Comment:
The FWC stated that it did not have any additional data or other information that would lead to different conclusions regarding the Miami blue's threats, life history, or other ecological attributes. The FWC supported our decision not to designate critical habitat. With regard to listing the other three blues as threatened due to similarity of appearance, the FWC supported the listing of the other blues, but suggested that it need only apply to the counties within the Miami blue's historical range. The FWC also encouraged the use of their management plan as a basis for the Federal recovery plan and other management and recovery actions.

Our Response:
We agree with the FWC's recommendation to apply similarity of appearance protection only in the counties within the Miami blue's historical range and have modified this final rule accordingly in response to these and other comments received. See Summary of Changes from Proposed Rule, below.

We intend to draw upon the State's management plan for the Miami blue and all other relevant sources during recovery planning and implementation efforts. We will be soliciting input from the State and other stakeholders, who are integral in the conservation of the subspecies, during recovery planning.

(21)
Comment:
The Florida Department of Environmental Protection (FDEP) found the proposed rule to be comprehensive and suggested no changes. The FDEP noted the thorough evaluation of research by Zhong
et al.
(2010), which demonstrated that a single treatment within normal mosquito control operations can kill substantial Miami blue larvae in targeted residential areas and, to a lesser extent, in adjacent nontarget areas. The FDEP suggested this research may indicate that normal mosquito control operations may have played a role in the historical decline of the Miami blue and other Keys insect fauna. The FDEP recommended that research be continued to better understand the impacts of mosquito control and exotic fire ants.

Our Response:
We agree that additional research will be helpful in developing a more thorough understanding of impacts from mosquito control, fire ants, and other threats. We are interested in working with others to better understand and address threats.

Federal Agency Comments

(22)
Comment:
The Naval Air Station Key West (NAS) expressed its commitment to work proactively with the Service to address potential issues should the Miami blue be listed as endangered. The commenter was concerned that, if critical habitat was designated, this would have significant impacts on the Navy's ability to conduct mission-essential activities.

Our Response:
We appreciate the Navy's assistance in the conservation of the Miami blue and acknowledge their concerns. We have worked cooperatively with the Navy regarding their Integrated Natural Resource Management Plan (INRMP) for NAS and realize it affords many provisions for successful ecosystem management and protections for listed species. We will coordinate with NAS to incorporate conservation actions for the Miami blue into their INRMP.

Public Comments

Comments Relating to Critical Habitat

(23)
Comment:
Several commenters encouraged the designation of critical habitat, emphasizing the need and importance of such designation, especially for reintroduction and recovery. One commenter stated that there is unquestionably habitat on the Keys and in south Florida that is critical to the butterfly's recovery. Another commenter stated that critical habitat designations are required to ensure successful reintroductions of Miami blue populations elsewhere in its historical range. These commenters indicated that such designation is imperative for achieving recovery goals for the Miami blue and recommended that high-quality target areas for reintroduction be listed as critical habitat. One commenter suggested that designating critical habitat has the benefit of doubling the likelihood that an endangered species will recover.

Our Response:
We acknowledge that there are benefits to designating critical habitat, as the commenters suggest (see
Benefits to the Subspecies From Critical Habitat Designation,
below). For the Miami blue, we have determined that increased harm to the subspecies and its habitat outweighs the benefits that critical habitat may provide (see
Increased Threat to the Subspecies by Designating Critical Habitat
and
Increased Threat to the Subspecies Outweighs the Benefits of Critical Habitat Designation,
below).

We disagree that designation of critical habitat is required or needed for successful reintroductions of the Miami blue, or that it is imperative for achieving recovery. Landowner permission is needed to reintroduce endangered species, even if unoccupied critical habitat is present. Some private property owners in the Keys have reportedly threatened to clear vegetation from undeveloped parcels to avoid restrictions regarding the butterfly (M. Minno,
in litt.
2011b; N. Pakhomoff-Spencer, consultant, pers. comm. 2011). Designation of critical habitat would also preclude the use of nonessential experimental populations (NEPs) under section 10(j) of the Act, a tool that could be useful to help reintroduce the subspecies in select areas within its historical range in the future. Section 10(j)(2) of the Act prohibits the use of NEPs where critical habitat is designated (the two are mutually exclusive). Overall, we believe that successful reintroductions and recovery will be dependent upon improved captive propagation and reintroduction techniques, removal of controllable threats, and cooperation of landowners, stakeholders, and partners.

Finally, with regard to the recommendation to include targeted high-quality reintroduction sites as critical habitat, there is currently no accepted, established list of high-quality reintroduction sites, as implied.

Preliminary assessments to determine the best potential reintroduction sites are outdated. Since originally assessed, additional populations of the Miami blue (using a different host plant) have been found, we have a better understanding of threats, and the captive colony no longer exists. We expect to reevaluate potential reintroduction sites to determine those most suitable with the help of our partners and prior to future captive propagation, reintroduction, and monitoring efforts.

(24)
Comment:
Two commenters suggested that it is not feasible to eliminate all threats throughout the Miami blue's historical range, but that designating critical habitat will have the benefit of identifying focused management zones for persistence. One commenter suggested that critical habitat should provide additional benefits in that spraying for mosquitoes would be prohibited, host plants would be completely protected, and invasive species would be removed. He argued that without designating critical habitat there are few regulatory mechanisms that will mitigate illicit activities contributing to habitat destruction at potential reintroduction sites within the historical range.

Another commenter acknowledged the value of designating critical habitat for conservation and management purposes and suggested that the limited amount of remaining vital habitat be identified for the Miami blue. He suggested that site assessments conducted during the unsuccessful reintroduction efforts could help identify this habitat. This commenter indicated that designating all undeveloped coastal areas as critical habitat is too sweeping and ignores the potential for more specific environmental requirements, which may help explain the failure of the reintroduction efforts. Additional studies to identify habitat requirements were recommended.

Our Response:
We agree that it is not possible to eliminate all threats throughout the Miami blue's historical range and acknowledge that designating critical habitat could help focus management actions. However, we determined that designation of critical habitat is not prudent for the Miami blue for the reasons stated below (see
Critical Habitat and Prudency Determination
and explanatory sections that follow).

With regard to threats, it is not realistic to assume that critical habitat designation would remove threats such as mosquito-control pesticides, completely protect host plants, or guarantee that invasive species would be removed, as one commenter purports. Critical habitat only provides protections where there is a Federal nexus (
i.e.,
actions that come under the purview of section 7 of the Act) (see
Benefits to the Subspecies from Critical Habitat Designation,
below). Mosquito control activities are not normally considered Federal projects, and would therefore not typically be subject to section 7 review. Furthermore, a landowner is not obligated to conduct conservation actions, such as the removal of invasive plants, when critical habitat is designated.

We disagree with the view that there are few regulatory mechanisms that will mitigate activities contributing to habitat destruction within the subspecies' historical range. Sections 7, 9, and 10 of the Act (see
Available Conservation Measures,
below) can provide useful regulatory mechanisms that will help conserve the Miami blue in its current and historical range. In addition, listing facilitates proactive programs and partnerships that can help protect and restore habitats and implement recovery actions (
e.g.,
section 4 and 6 of the Act; see
Available Conservation Measures,
below). In short, some commenters may have overestimated the potential benefits of critical habitat designation and underestimated the regulatory protections that the Act confers simply when a species is listed as endangered.

Finally, we agree that additional studies to identify specific habitat requirements are needed. Such studies would be helpful to both understanding the Miami blue's specific physical and biological habitat needs and for increasing the likelihood of successful reintroductions in the future. These actions will likely be undertaken with researchers and others during recovery planning and implementation.

(25)
Comment:
One commenter stated that the conditions given under 50 CFR 424.12(a)(1) for a not prudent determination would apply to most endangered species, especially insects that maintain small populations. The commenter contended that the increased threat to the Miami blue from designating critical habitat would be minimal because most suitable habitat exists within protected State and Federal lands.

Our Response:
We disagree that a “not prudent” determination would apply to most endangered species. However, we acknowledge that it may often apply to endangered insects and plants that are highly sought after by collectors, hobbyists, and enthusiasts (
e.g.,
butterflies, tiger beetles, orchids, cacti). Although we acknowledge that most suitable habitat for the Miami blue is on State, Federal, or other conservation land, we do not agree with the commenter's view that increased threat to the butterfly from designation would be minimal. In fact, we find that the increased threat may be substantial in that it could exacerbate the already serious threats of collection, vandalism, disturbance, fire, and other harm from humans (see
Increased Threat to the Subspecies by Designating Critical Habitat,
below).

(26)
Comment:
Two commenters suggested that since high-quality target areas for reintroduction are all located on Federal, State, or conservation lands, there would not be significant economic consequence to designating critical habitat.

Our Response:
We agree that the majority of suitable and potential habitat for the Miami blue occurs on Federal, State, or conservation lands. Our determination is that critical habitat designation for the Miami blue is not prudent. Therefore, an economic analysis was not required by the Act and was not conducted.

Comments Related to Taxonomy and Current Distribution

(27)
Comment:
The National Environmental and Planning Agency of Jamaica provided comments prepared by the Scientific Authority of Jamaica regarding the relative abundance and distribution of the cassius blue butterfly in that country. It indicated that it did not have data to support the suspected decline in Jamaica and had insufficient evidence to concur with the proposal. The agency suggested a population and distribution study was needed to determine conservation status in Jamaica.

Our Response:
We appreciate the comments provided. However, the proposed rule did not suggest listing the cassius blue butterfly on the basis of imperilment. Rather, it proposed threatened status for the cassius blue solely due to its similarity in appearance to the Miami blue, and to provide greater protection for the Miami blue. In response to comments received during the public comment period, the similarity of appearance aspect of the final rule has been modified. The Service no longer sees a need to list the cassius blue, ceraunus blue, or nickerbean blue butterflies as threatened throughout their ranges. Rather, we believe that prohibiting collection of these similar butterflies only in the historical range of the Miami blue in Florida is sufficient for minimizing the threat of collection of the Miami blue.

Therefore, the cassius blue will not be listed under the similarity of appearance provision of the Act in Jamaica (see Summary of Changes from Proposed Rule, below.).

(28)
Comment:
Five commenters expressed concern regarding taxonomy and current distribution. Another commenter stated that the question of taxonomic status has been settled since multiple, independent researchers have verified the unique standing of the Miami blue by genitalic dissection (See also Comment #29 and Response below).

One commenter, who had previously identified captive-reared BHSP specimens as
Cyclargus thomasi bethunebakeri,
noted limitations in contemporary specimens and available literature about
Cyclargus
taxa. This commenter indicated that there are morphological and genetic differences between historical and contemporary populations of
C. thomasi
in Florida [noting Saarinen (2009)] and suspected that these disparities may indicate the presence of a Cuban entity now in the lower Keys. However, he acknowledged that he was unaware of any detailed morphological or genetic investigations of the Cuban entity. Considering Florida's proximity to other West Indian populations, he suggested that it is possible that multiple genetic entities of
C. thomasi
have occurred (or do occur) in Florida, and the presence of a more genetically diverse metapopulation within the KWNWR may be the result of more recent immigrations from Cuba. Further, this commenter noted an unconfirmed report that captive-bred Miami blue larvae did not readily accept balloonvine, reinforcing his notion that historical and contemporary populations are not the same entity.

Another commenter stated that the Service does not have the necessary information to determine if
Cyclargus thomasi bethunebakeri
is globally endangered or not since
C. thomasi
has recently been reported from Cuba and appears to be secure there. He indicated that it has not been determined if the entity in Cuba is different from the subspecies in Florida and that it is possible that these are the same subspecies. He also noted that
C. thomasi bethunebakeri
has been reported from the Bimini Islands in the western Bahamas. In his view, the entity in Cuba may be the same subspecies and it may be secure; therefore, the Florida taxon is not endangered, and should not be listed at this time.

Another commenter noted that the
Cyclargus thomasi
complex was not well defined, citing Johnson and Balint (1995). This commenter recommended that the taxonomic status be clarified.

Another commenter indicated the differences between photographs she had taken from BHSP with those she had discovered within KWNWR. She suggested the possibility that the KWNWR colonies may more closely resemble those of Cuba and elsewhere, rather than those from mainland Florida. She noted that the range of the butterfly does not seem well documented in recent years, and that the full range outside of the known locations should be determined.

Our Response:
We understand the commenters' questions and uncertainty regarding taxonomy and distribution. We disagree with the comment that the subspecies is not well defined or described. The best scientific and commercial information and evidence indicates that
Cyclargus thomasi bethunebakeri
is a distinct, well-described and examined taxon (see
Taxonomy,
above) and that its distribution is limited (see
Historical Distribution
and
Current Distribution
).

Some concerns over the taxonomy and current distribution are based on discussion of a similar looking blue butterfly recently documented in Cuba. Historically, the nickerbean blue,
Cyclargus ammon,
was reported from Cuba. However, Hernandez (2004, p. 100) indicated that an undetermined subspecies of
Cyclargus thomasi
is now also known to occur on the island. Craves (2004, p. 43) indicated that she observed
C. thomasi
commonly at two locations in Cuba: Cayo Paredon and Santiago de Cuba. Based on examination of photographs, she suggested that these appeared to be
C. t. bethunebakeri.
However, no specimens were collected and, to our knowledge, there have been no additional studies of the Cuban
C. thomasi.
Craves (2004, p. 43) suggested the possibility that
C. t. bethunebakeri
recolonized Florida from Cuba.

We acknowledge the concerns raised by some commenters regarding taxonomy, but we do not have any scientific evidence to suggest that
Cyclargus thomasi bethunebakeri
also now occurs in Cuba or that it recently immigrated from Cuba to Florida. Other subspecies of
C. thomasi
occur in the Caribbean (Smith
et al.
1994, p. 129), and it is possible that the unidentified
C. thomasi
in Cuba is one of these subspecies, another subspecies that has not yet been described, or possibly
C. t. bethunebakeri.
Additional work to better understand the full range of the Miami blue outside of the known locations would be helpful. Surveys of remote areas in Florida are ongoing; additional surveys in the Bahamas (and Cuba) would be helpful. Additional research could help determine if other Caribbean taxa are also imperiled.

It is unlikely that
Cyclargus thomasi
has only recently established in the lower Keys, as one commenter suggested. There were few historical surveys for butterflies at BHSP or KWNWR; therefore, it is unknown how long the Miami blue occurred at these locations prior to their discoveries. By contrast, many of the other islands in the lower Keys have been continually monitored for butterflies for several decades. If the Miami blue had recently colonized the lower Keys, it seems likely that it would have attempted to establish at numerous locations along the chain of islands, thereby being observed and reported prior to ultimately colonizing BHSP and KWNWR.

The concern that captive Miami blue larvae may not have readily accepted balloonvine as the basis of historical and contemporary populations being different entities seems unfounded. Captive individuals and artificial conditions may produce responses that are different than those occurring in the wild. Available scientific literature documents a variety of host plants for the Miami blue (see
Life History
and
Habitat
under Background—and response to Comment #6, above). Balloonvine was likely only one of several legumes used by historical Miami blue populations.

Based on the best scientific information, including recent genetic work, we find that
Cyclargus thomasi bethunebakeri
is a distinct and unique entity, that it is limited in distribution (
i.e.,
Florida, possibly Bahamas), that it is imperiled, and that listing is warranted. We lack any substantial information or evidence that the Cuban entity is the same taxon and have no information on that entity's abundance or status.

(29)
Comment:
In support of our determination, one commenter, who had conducted her dissertation on the taxon, unequivocally stated that the Florida subspecies,
Cyclargus thomasi bethunebakeri,
is unique and imperiled. In addition to the work by multiple, independent scientists who have verified the unique standing of the Miami blue through dissection, this commenter cited her own additional genetic analyses, which compared genetic sequence data of a mitochondrial gene useful in elucidating species distinctions, and her finding of sequence differences between multiple specimens of
C. thomasi
from Florida, Cuba, and the Bahamas. The sequence data and genitalic dissections

make it possible to separate the
bethunebakeri
from others in the
C. thomasi
complex. This commenter definitively stated that
C. thomasi bethunebakeri
is unique and imperiled. She noted that other Caribbean taxa are also unique and recommended research to determine if these are also imperiled. Sequencing of specimens at additional mitochondrial and nuclear markers would be helpful in more fully understanding the relationship between Floridian and other Caribbean taxa of
Cyclargus thomasi.

Our Response:
We agree. Based on the best scientific information, including recent genetics work, we find that
Cyclargus thomasi bethunebakeri
is a distinct and unique entity, that it is limited in distribution (
i.e.,
Florida, possibly Bahamas), that it is imperiled, and that listing is warranted. We agree with the commenter's suggestion for additional research to help determine if other Caribbean taxa are also imperiled.

Comments Related to Threats

(30)
Comment:
One commenter provided considerable new information on exotic green iguanas within KWNWR, potential impacts on the Miami blue, and prospects for eradication. This commenter identified studies to determine if green iguanas are eating blackbead in KWNWR as an immediate research need. He also noted that, worldwide, there are no known cases in which an exotic reptile, once established in an area, has been eradicated (citing G.H. Rodda, pers. comm. 2011).

Our Response:
We have incorporated new information pertaining to green iguanas within KWNWR into the text of this final rule (see
Summary of Factors Affecting the Species,
Factor E). We agree that determining iguana food sources, both at KWNWR and within habitat formerly occupied by Miami blues, is a crucial first step in preventing further harm to the Miami blue from this exotic species. Because Miami blues have historically fed on a variety of legumes, studies are needed to determine iguana seasonal dietary preferences in south Florida an

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2012-8088. Public record. Not legal advice.