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Sea Turtles in the 
Netherlands Antilles

Until recently, information on sea turtle
nesting in the Netherlands Antilles con-
sisted mostly of anecdotal accounts and
sea turtle nesting was considered to be a
rare or accidental occurrence. DEBROT ET

AL. (2005. Caribbean Journal of Science
41:334–339) cited several recent studies
and presented documentation of several
additional sea turtle nesting beaches on
Curaçao, Klein Curaçao, St. Eustatius,
and St. Maarten. Historically, most stud-
ies have focused on large sea turtle nest-
ing beaches, whereas the results of this
study support the idea that small, scat-
tered nesting beaches could cumulatively
contribute significantly to both repro-
ductive output and recovery potential of
several species when examined on a
regional scale.

Impact of Foxes on 
Freshwater Turtle Populations

The resilience of a freshwater turtle pop-
ulation to stage-specific predation is den-
sity-dependent, and some species are
more susceptible to predation because of
their life-history strategies. Nest preda-
tion by introduced Red Foxes (Vulpes
vulpes) on Australian freshwater turtles is
a major source of mortality, but its full
impact has yet to be evaluated.
Freshwater turtles are long lived, and a
population decline resulting from nest
predation by foxes may take a long time
to become evident. SPENCER AND

THOMPSON (2005. Conservation Biology
19:845–854) evaluated the impact of
foxes on population growth and patterns
of survival of two widely distributed
Australian freshwater turtles in the
Murray River, where nest predation rates
have previously been reported at above

95%. They estimated densities and sur-
vivorship of Emydura macquarii and
Chelodina expansa from the nest to adult
stage, and then conducted a fox-removal
program to determine the impact of
foxes on populations of these species.
Chelodina expansa was five times less
abundant than E. macquarii. Densities of
C. expansa nests were low and situated
away from shore, and nest-predation
rates were half those of E. macquarii.
Emydura macquarii populations had low
productivity and relied on a standing
crop of adult turtles for population main-
tenance, whereas C. expansa had rela-
tively more juveniles in the population
and was less reliant on adult survival.
Despite its vulnerable status, C. expansa
is relatively more stable than E. mac-
quarii, primarily because there were pro-
portionally more juveniles in the popula-
tion. Management options focusing on
reducing adult mortality in both species
will be most effective.

Destructive Collecting Practices 
and Reptilian Abundance

Collecting reptiles often results in
irreparable damage to microhabitats.
Such activities and the concomitant
destruction of habitats are increasing in
frequency due largely to rising demand
for reptiles in the pet market. GOODE ET

AL. (2004. Journal of Wildlife Management

68:427–432) compared abundance of
reptiles on rock outcroppings in Arizona
before and after disturbance. Results sug-
gest that destructive collecting techniques
led to a decrease in the abundance of
diurnal lizards, which preferred undis-
turbed portions of rock outcrops. The
authors recommended that collecting
methods be strictly regulated and that
implementation of these regulations be
accompanied by increased enforcement
to render them effective.

Loggerhead Turtle Nesting Trends
HAWKES ET AL. (2005. Oryx 39:65–72)
analyzed a 24-year set of data from inten-
sive monitoring of a nesting beach at
Bald Head Island, North Carolina, USA
and more limited data from nearby rook-
eries to investigate trends in Loggerhead
Turtle (Caretta caretta) nesting numbers.
Re-migrating turtles were larger and had
larger annual clutch frequencies than
neophyte turtles. However, no statistical
evidence suggested either an increasing or
decreasing trend in numbers of clutches
laid per year, although a significant
decrease in the number of turtles nesting
and number of clutches laid per year was
found over the period since 1991.

Efficacy of 
Green Turtle Headstarting

Headstarting is a management technique
employed to enhance recruitment of tur-
tles into diminished or extirpated marine
turtle populations. Although numerous
worldwide projects have been imple-
mented, few detailed investigations have
examined the efficacy of the concept.
BELL ET AL. (2005. Oryx 39:137–148)
noted that between 1980 and 2001,

206 IGUANA  •  VOLUME 12, NUMBER 3  •  SEPTEMBER 2005 CONSERVATION RESEARCH REPORTS

C O N S E R V A T I O N  R E S E A R C H  R E P O R T S

Leatherback Sea Turtles (Dermochelys cori-
acea) are nesting more frequently in the
Netherlands Antilles.

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Populations of Chelodina expansa in Australia
appear to be less vulnerable than those of
Emydura macquarii to nest predation by intro-
duced Red Foxes (Vulpes vulpes), presumably
because nest densities of the former are low
and nests are located farther from shores.

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Loggerhead Turtles (Caretta caretta) often
nest on beaches in subtropical and even tem-
perate zones.

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IGUANA  •  VOLUME 12, NUMBER 3  •  SEPTEMBER 2005 207CONSERVATION RESEARCH REPORTS

16,422 captive-raised hatchlings and
14,347 yearling Green Turtles (Chelonia
mydas) were released from the Cayman
Turtle Farm. Approximately 80% of all
turtles released were subject to some
form of tagging. A total of 392 tagged
animals have been recaptured at intervals
of up to 19 years. Of this total, 160 indi-
viduals were captured in the Cayman
Islands and 232 were recorded from
other locations within the wider
Caribbean and southeastern United
States. A positive relationship exists
between time at large and size at recap-
ture, and data suggest that growth rates
are comparable to those of wild Green
Turtles in the region. Age at maturity
may be as short as 15–19 years, depend-
ing on stage at release. Results show that
some headstarted turtles are moving
around the Caribbean, surviving for long
periods of time, contributing to local
breeding population, and may be dis-
playing age-related shifts in habitat uti-
lization similar to those recorded for wild
individuals.

Marine Turtles in The Gambia, 
West Africa

BARNETT ET AL. (2004. Oryx 38:203–
208) reported the first systematic survey
of the marine turtles of the 80 km of The
Gambian coastline, and brought together
new data and all past records and reports
of marine turtles in The Gambia. Green
Turtles (Chelonia mydas) are the most
abundant turtles and this is the only
species so far observed nesting in The
Gambia, with peak nesting between
August and October. Although 75% (60
km) of The Gambian coastline appears
to be suitable for turtle nesting, most
nesting activity is confined to the south-
ern coastline. Offshore foraging habitat is
apparently extensive. Strandings of Green
Turtles, Olive Ridley Turtles (Lepidochelys
olivacea), Leatherback Turtles (Dermo-

chelys coriacea), and Hawksbill Turtles
(Eretmochelys imbricata) have been
recorded, but we were unable to find evi-
dence for Loggerhead Turtles (Caretta
caretta). Threats are mainly of human
origin, and include illegal harvesting of
eggs, juveniles, and adults, as well as mor-
tality as fisheries bycatch, including
trawling. One stranded Green Turtle
apparently had fibropapilloma disease.
The major threat to nesting habitats is
erosion and unregulated development of
the coast for tourism. Marine turtles are
fully protected under Gambian law.

Lesser Antillean Snakes: 
Conservation Concerns

Thirty-three islands in the Lesser Antilles
range in area from 0.06–1,510 km2 and
collectively harbor 25 species of snakes
representing five families and 10 genera.
HENDERSON (2004. Oryx 38:311–320)
noted that the islands have suffered at
least six, and possibly as many as 11, his-
torical extirpations and at least one his-
torical extinction. The number of snake
species per island is 1–5, and species rich-
ness is correlated with island size and
habitat diversity. Islands that harbor three
or more species exhibit greater habitat
diversity, are larger, have a higher maxi-
mum elevation, and are situated closer to
the South American mainland, the
source area for most genera. North of the
Guadeloupe Archipelago, islands support
one or two species (an Alsophis or an
Alsophis and a Typhlops). From the

Guadeloupe Archipelago southward,
snake faunas have species belonging to
genera that are widespread on the
Neotropical mainland: Boa, Corallus,
Chironius, Clelia, Liophis, Mastigodryas
and Bothrops. Between 50 and 75% of
the Lesser Antillean snake fauna preys on
Anolis lizards. Snake faunas in the Lesser
Antilles are not saturated, and many
islands could support additional species;
fossil evidence and written records indi-
cate that they did. The islands have a
5,000-year history of habitat alteration,
but introduced predators probably have
had the greatest negative impact on
snakes. The potential establishment of an

alien snake (e.g., Elaphe guttata) into the
Lesser Antilles is a valid concern.
Preventing additional introductions of
alien predators and protecting satellite
island populations of threatened species
are the two most important mechanisms
for snake conservation in the region.

An adult Green Turtle (Chelonia mydas) on a
Grand Caymanian beach.

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Hawksbill Turtles (Eretmochelys imbricata) have been recorded along The Gambian coast.

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Introduced predators, notably the mongoose
(Herpestes javanicus), undoubtedly have had
the greatest negative impact on native Lesser
Antillean snake populations. Mastigodryas
bruesi is somewhat less vulnerable than
many other species because of its arboreal
inclinations.

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Santos, G., J. Pacheco, G. Ceballos, 
F. Mendoza-Quijano, G. Daily, and 
P. Ehrlich. COUNTRYSIDE BIOGEO-
GRAPHY IN REPTILE AND
AMPHIBIAN COMMUNITIES IN
SOUTHERN COSTA RICA: CON-
SERVATION VALUE OF HUMAN
DOMINATED LANDSCAPES. The
future of biological diversity in the trop-
ics depends largely on the conservation
value of human-dominated lands. In this
study, we investigated the distribution of
amphibians and reptiles in five habitats
of southern Costa Rica: relatively exten-
sive forest (227 ha), coffee plantation,
pasture, coffee with adjacent forest rem-
nant (<35 ha), and pasture with adjacent
forest remnant (<35 ha). Species richness,
composition, and abundance varied sig-
nificantly with habitat type and distance
from the extensive forest. Additionally,
we recorded the local extinction of at
least five species, likely as a result of
human-induced changes such as forest
fragmentation, introduced diseases, and
global warming. Of the 67 amphibian
and reptilian species recorded in our

plots, most (48, 68%) were found in
forests and forest fragments, 36 (50%) in
coffee plantations, and 38 (51%) in pas-
tures. Additionally, 20 were recorded
exclusively in extensive forest and forest
fragments, eight in coffee, and eight in
pastures. Relatively continuous forest and
small forest patches in combination with
coffee plantations are important for the
maintenance of the region’s biological
diversity, despite large scale negative
human activities.

Santos, G., J. Pacheco, and G. Ceballos.
NATURAL PROTECTED AREAS
AND THE CONSERVATION OF
AMPHIBIANS AND REPTILES IN
MEXICO: PRIORIZING SPECIES
AND AREAS FOR CONSERVATION
STRATEGIES. One principal goal in
establishing protected natural areas is to
preserve ecosystems and associated biodi-
versity in order to perpetuate natural evo-
lutionary processes. This study evaluates
the efficiency of protected natural areas
for the conservation of Mexican amphib-
ians and reptiles. These groups are highly
diverse in Mexico, with 1164 species
(360 amphibians and 804 reptiles) and
high endemism (60%, 241 and 450,
respectively). We used 34 inventory lists
from protected areas and considered con-

servation status, geographic range, and
endemism of listed species to build a
hierarchical system to identify priority
species for conservation. The comple-
mentary study of these areas revealed that
56% of the Mexican herpetofauna is
excluded from the protected areas.

Jessop, T.S., J. Imansyah, D. Purwandana,
H. Rudiharto, and C. Ciofi. MANAGE-
MENT AND CONSERVATION
REQUIREMENTS FOR KOMODO
DRAGON POPULATIONS IN
KOMODO NATIONAL PARK,
INDONESIA. Within archipelagos,
populations may exhibit intraspecific dif-
ferences requiring plasticity in manage-
ment and conservation practices. Four of
the five island populations of the
Komodo Dragon (Varanus komodoensis)
reside within the world heritage-listed
Komodo National Park in eastern
Indonesia. To identify current manage-
ment and conservation requirements for
the park’s dragon populations, a con-
certed long-term research program has
been established. Results indicate that
major differences in demography and
ecology exist between dragon popula-
tions on the two large islands of Komodo
and Rinca and the two small islands of
Motang and Kode. Specifically, island
area influences prey diversity and avail-

208 IGUANA  •  VOLUME 12, NUMBER 3  •  SEPTEMBER 2005 CONSERVATION RESEARCH REPORTS

1 9 T H  A N N U A L  M E E T I N G  O F  T H E
S O C I E T Y  F O R  C O N S E R V A T I O N  B I O L O G Y

Universidade de Brasília, Brazil
22 July 2005

Excerpts from abstracts dealing with the conservation of reptiles.

The Brown Basilisk (Basiliscus vittatus) actu-
ally may benefit from forest fragmentation
because of its dependence on edges. Many
species however suffer when human activi-
ties break up contiguous stretches of suitable
habitat into pieces too small to support
viable populations.

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Ctenosaura nolascensis is restricted to an
island in the Gulf of California, México.
Like all islands in the Gulf, San Pedro
Nolasco is a protected area. Enforcement,
unfortunately, is inconsistent. Nevertheless,
many Mexican species, including many that
are threatened or endangered, have no pop-
ulations in protected areas.

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Populations of Komodo Dragons (Varanus
komodoensis) remain vulnerable to human
affects on their habitat. Reductions in the
population size of Timor Deer, attributable
to poaching, affected body condition and
population size structure of the Dragons.

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IGUANA  •  VOLUME 12, NUMBER 3  •  SEPTEMBER 2005 209CONSERVATION RESEARCH REPORTS

ability, which, in turn, influences the
density, growth, and body size of drag-
ons. The Motang Island population, esti-
mated at 51 ± 6 post-hatchling individu-
als, recorded a recent reduction in catch
per unit effort, body condition, and
changes in population size structure.
Such changes have resulted from a
decreased abundance of Timor Deer, due
to suspected poaching. Increased resource
security and potential augmentation of
prey density may be required to conserve
this population.

Gerber, G.P. and A.C. Alberts.
TRANSLOCATION AS A RECOV-
ERY STRATEGY FOR THE CRITI-
CALLY ENDANGERED TURKS
AND CAICOS IGUANA. In response
to threats from introduced mammalian
predators and human development,
Turks and Caicos Iguanas (Cyclura cari-
nata) were translocated in January 2002
and 2003 from two large but threatened
island populations to four small pro-
tected islands with suitable habitat but
lacking extant iguana populations.
Translocation islands received 18–82
adult iguanas of equal sex ratio from one
of the two source islands, depending
upon their area (1–12 ha) and estimated
adult carrying capacity. Source and
translocated populations were monitored
2–3 times annually between 2002 and
2005. By five months, post-translocation
adult iguanas on translocation islands
had established normal movement pat-
terns and were exhibiting normal or
increased growth rates relative to source
populations. Successful reproduction has
occurred on all translocation islands each
year since reintroduction and iguanas
hatched on translocation islands are
exhibiting growth rates 2-4 times that of
juveniles of the same age on source
islands. This has resulted in a decrease in

age at maturity on translocation islands,
relative to source islands, from 6–7 years
to 2–4 years. We attribute increased
growth rates on translocation islands to
decreased intra-specific competition (i.e.,
density), relative to source populations,
and predict that growth rates will return
to baseline as carrying capacities are
approached.

Freire, E.M.X., U. Caramaschi, M.T.
Rodrigues, and S.T. Silva. EFFECTS OF
THE FRAGMENTATION OF
ATLANTIC FOREST IN THE
STATE OF ALAGOAS (NORTH-
EASTERN BRAZIL) ON THE
DIVERSITY OF SPECIES OF
LIZARDS AND SNAKES. The
Atlantic Forest of Brazil has become frag-
mented and reduced to about 7% of its
original size. In the Northeastern Region,
the most significant remnants are in the
States of Bahia (6%) and Alagoas (2%).
An inventory of different-sized forest
fragments in the state of Alagoas involved
2,950 person-hours. Species diversity was
high and 19% of the species were
endemic to the northern part of the
Atlantic Forest and two were new to sci-
ence. The smallest area exhibited the
highest diversity index, which two subse-
quent studies (1,100 person-hours) con-
firmed. This diversity may not be main-
tained, because the populations of
animals in these fragments may not be
viable in the long term.

Bennett, D. CONSERVATION OF A
LARGE FRUGIVOROUS MONI-
TOR LIZARD IN THE PHILIP-
PINES. Frugivory is a rare strategy in

lizards, but, in the Philippines, a group of
large (>9 kg) Varanus lizards has evolved
to become specialized frugivores in dipte-
rocarp forest. Efforts to understand their
ecology and promote their conservation
have been hampered by their highly
arboreal and secretive behavior. Here I
report on the behavioral ecology of a
population of Varanus olivaceus in frag-
mented forest on Polillo Island, Quezon
Province, that have been the subject of a
non-destructive and largely non-intrusive
study instigated in 1999. Despite the
large numbers of fruit types available to
animals in dipterocarp forest, the lizards
feed mainly on fruit from just four gen-
era. They act as unique dispersers of
Pandanus seeds, which results in high
densities of these plants along slopes and
ridges, which, in turn, has important
implications for other fauna and flora
dependent on Pandanus microhabitats.
Their inability to fly means that large
frugivorous lizards are more vulnerable to
forest fragmentation than sympatric fru-
givores (birds and bats), but the results of
this study indicate that populations can
be maintained in disturbed forest if a few
key resources are maintained.

Translocated populations of Turks and
Caicos Iguanas (Cyclura carinata) are show-
ing growth rates and ages at maturity sug-
gesting that they are taking full advantage of
resources that are superabundant as long as
the population of iguanas remains below
carrying capacity.

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Varanus olivaceus is one of very few frugivo-
rous lizards in the world and acts as an
important disperser of Pandanus seeds.

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Animal populations inhabiting the Atlantic
forest of northeastern Brazil are becoming
increasingly fragmented, reducing the
chances of maintaining long-term biodiver-
sity. Particularly vulnerable are large species
and those, such as Corallus hortulanus,
dependent on forest habitats.

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