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Conservation of the Indonesian
Herpetofauna

Indonesia is an archipelagic nation com-
posed of some 17,000 islands of varying
sizes and geological origins, and with
marked differences in flora and fauna.
Indonesia is considered one of the Earth’s
megadiversity centers. According to the
Biodiversity Action Plan for Indonesia,
16% of all amphibian and reptilian
species occur in Indonesia, a total of over
1,100 species. New research activities,
launched in the last few years, indicate
that these figures may be significantly
higher than generally assumed.
Herpetological research in Indonesia,
however, has not progressed at a rate
comparable to that of neighboring coun-
tries. In the last 70 years, 762 new taxa
have been described from southeastern
Asia, of which only 262 were from
Indonesia. In general, the herpetofauna
of Indonesia is poorly understood com-
pared to the herpetofauna of neighboring
countries. Moreover, geographic distribu-
tion patterns for many species are poorly
known. In view of the alarming rate of
forest loss, measures for more effective
protection of the herpetofauna of
Indonesia are urgently required. The
IUCN Red List status of virtually all
Indonesian species remains unknown,
and no action plans have been formu-
lated. ISKANDAR AND ERDELEN (2006.
Amphibian and Reptile Conservation
4:60–87) provided an overview of the
herpetofauna as part of Indonesia’s biodi-
versity, outlined the history of herpeto-
logical research in the region, and identi-
fied major gaps in our knowledge of the
Indonesian herpetofauna. The latter
addressed the contents and shortcomings
of compilations of lists of protected or

threatened species by national and inter-
national authorities and major threats to
the Indonesian herpetofauna, and pro-
posed measures for better long-term con-
servation.

Rangeland Management and a
Tallgrass Prairie Herpetofauna

The Flint Hills of Kansas and Oklahoma
have changed dramatically in the past 30
years, largely due to conversion from nat-
ural tallgrass prairie to cattle rangeland.
Because the effects of fire and grazing on
the herpetofauna are poorly understood,
WILGERS ET AL. (2006. Herpetologica
62:378–388) examined how different
land management practices, such as cat-
tle stocking rates and seasonal burning,
affected amphibians and reptiles.
Fourteen herpetofaunal surveys docu-
mented the number of individuals, envi-
ronmental conditions, and community
dynamics, including the probabilities of
local extinction or permanent emigra-
tion. Land-use practices during the study
were traditional season-long stocking
during the first 10 years, burning pas-
tures in alternate years. In 1999, land
management practice changed to inten-
sive early cattle stocking, combined with
annual burning. Data suggested that
burn frequencies and cattle stocking
affected the herpetofauna, with rates of
species loss higher during years of burn-
ing than in non-burn years.

Forest Fragmentation and
Community Structure in Costa Rica

Habitat fragmentation is one of the most
serious threats to biodiversity. The
increasing conversion of land to agricul-
tural uses in Costa Rica has greatly
reduced forested area, and has more than
doubled the number of forest fragments
in some areas. Reptiles and amphibians
occur at high densities in the Neotropics,
but we know little about their responses
to land-use changes. BELL AND

DONNELLY (2006. Conservation Biology
20:1750–1760) examined community
and population structure of frogs and
lizards in the fragmented landscape sur-
rounding La Selva Biological Station,
Costa Rica to better understand the
effects of forest fragmentation. Nine frag-
ments, ranging in area from 1–7 ha, were
compared to an 1,100-ha area in the pre-
serve. Community structure of frogs and
lizards in forest fragments differed signif-
icantly from that of the intact forest com-
munity. Lizard density was higher and
frog density was lower in forest fragments
than in continuous forest, and 25% of
species found in continuous forest were
not observed in fragmented forest.
Species composition and relative abun-
dance varied among sites according to
fragment size. The extent of isolation and
habitat variables did not affect species
richness, composition, or nesting. The
authors concluded that small populations

128 IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 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

The Great Plains Skink (Eumeces obsoletus) is one of many prairie-dwelling species affected by
land management practices.

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The endangered Giant River Terrapin
(Batagur baska) is one of many Indonesian
reptiles about which very little is known.

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IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 129

are threatened by edge effects, and that
preservation of large reserves is crucial for
the preservation of reptiles and amphib-
ians in La Selva and in other fragmented
habitats.

The Pigeon Paradox
Conservation of urban nature is rarely
discussed, yet, as ecosystems continue to
shrink and change due to urbanization,
conservation will increasingly rely on
urban habitats to preserve natural com-
munities. DUNN ET AL. (2006.
Conservation Biology 20:1814–1816)
refer to this phenomenon as the “pigeon
paradox.” Based on assertions that cur-
rent conservation action is insufficient,
people are more likely to take conserva-
tion action when they have direct experi-
ences with the natural world, and
humans in the future will experience
nature primarily through contact with
urban wildlife, the authors concluded
that providing opportunities for children
living in cities to experience nature is
essential, as the future of conservation

will depend largely on the urban culture.
To meet this need, societies must restore
urban ecosystems, improve access to
urban nature, and carefully consider the
costs and benefits linked to how we por-
tray non-native and “pestiferous” urban
species (such as “pigeons”).

Climate Change and 
Herpetofaunal Declines

ARAÚJO ET AL. (2006. Journal of
Biogeography 33:1712–1728) explored
the relationship between current
European distributions of amphibian
and reptilian species and potential
impacts of climatic warming by asking
what proportion of species are projected
to lose and gain suitable climate space;
whether species projections vary accord-
ing to taxonomic, spatial, or environ-
mental properties; and what climate fac-
tors might be driving projections of loss
or gain in suitable environments.
Distributions were projected into the
future using five climate-change scenar-
ios for 2050, and projections were made
according to two extreme assumptions:
species have unlimited dispersal ability or
species have no dispersal ability. Many
species were projected to expand distri-
butions if dispersal is unlimited, mainly
because warming in the cooler northern
ranges of species creates new opportuni-
ties for colonization. If species are unable
to disperse, then most species were pro-
jected to lose range, mainly in southwest-
ern Europe, where dry conditions were
projected to increase. The authors sug-
gested that the impact of increasing tem-
peratures on amphibian and reptilian
species might be less deleterious than pre-

viously postulated. However, the ability
of species to cope with climatic warming
may be offset by projected decreases in
the availability of water, particularly for
amphibians. Limited dispersal ability
may further increase the vulnerability of
amphibians and reptiles to changes in cli-
mate.

Island Differences in 
Komodo Dragons

Species inhabiting archipelagos are often
characterized by high levels of interpop-
ulation divergence (e.g., size-related
traits). This divergence may, in turn,
influence life history. To facilitate better
management and conservation of the
Komodo Dragon (Varanus komodoensis),
JESSOP ET AL. (2007. Biological
Conservation 135:247–255) identified
demographic differences between two
island populations in Komodo National
Park, Indonesia. Comparison of data col-
lected from dragon populations inhabit-
ing Rinca Island and the much smaller
Gili Motang Island indicated that
between 1994 and 2004, the Komodo
Dragon population on Gili Motang sig-
nificantly decreased its mean body mass,
body condition, and relative abundance.
These results suggest that the numerically
small Gili Motang population was oscil-
lating downward; in contrast, the Rinca
Island population had been relatively sta-
ble. These results emphasize the necessity
for managers of this priority conservation
species to understand further the inher-
ent functional differences among dragon
populations to develop island-specific
management units. Current manage-
ment practices instigated by Komodo
National Park management ignore small-

CONSERVATION RESEARCH REPORTS

Costa Rican lizards, such as this Black Iguana
(Ctenosaura similis), which benefit from
breaks in forest canopies that provide effec-
tive basking sites, often increase in numbers
in response to forest fragmentation.

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Green Iguanas (Iguana iguana) are common urban species both where the species is native and
in areas, such as southern Florida, where it has been introduced.

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Many European reptiles, such as this Slow
Worm (Anguis fragilis) are expected to
expand their ranges in response to global
warming.

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island dragon populations and thus run
the risk of being unable to detect adverse
effects for populations that are potentially
most prone to decline.

Dim Future for Fiji’s Endemic
Crested Iguana

The Fijian Crested Iguana (Brachylophus
vitiensis) was not described until 1981,
but it appears to be secure on only one
small island sanctuary. HARLOW ET AL.
(2007. Oryx 41:44–50) surveyed 17
islands in western Fiji with historical
records of Crested Iguanas, and found
that iguanas were “extremely rare or
extinct” on all of those islands. Iguanas
were recorded on four of the surveyed
islands, but the authors suggested that all
of these populations are small and con-
tinuing to decline, primarily due to
ongoing forest habitat destruction by fire
and goat grazing and the introduction of
feral cats. Most distressing were the
repeated surveys of the cat-free, uninhab-
ited island of Monuriki, where a popula-
tion estimate of 40–80 iguanas in 1998
had decreased by a factor of four in 2003

— so low that an estimate was no longer
possible. The authors indicated that these
data should spur the government of Fiji
to instigate immediate conservation
action on behalf of the nation’s most
famous wildlife icon.

Effects of Agricultural Practices 
on Wood Turtles

In North America, the spatio-temporal
scale of deforestation has resulted in a
94% decrease in temperate forests within
360 years. Despite the enormous scale of
this disturbance, agriculture is so perva-
sive in modern society that its impacts
are highly underappreciated. SAUMURE

ET AL. (2007. Biological Conservation
135:581–591) investigated the impact of
current agricultural practices on a distur-
bance-dependent species in southern
Québec, Canada. Of 30 Wood Turtles
(Glyptemys insculpta) followed via radio-
telemetry, 20% died as a result of agricul-
tural activities. Anthropogenic mortality
estimates for adults and juveniles in 1998
were 0.10 and 0.18, respectively. For
1999, these values were 0.13 and 0.17,
respectively. Of those turtles that sur-
vived, many had injuries inflicted by
agricultural machinery. Sub-lethal muti-
lation rates for adults were 90 ± 3% in
both years, whereas the maximum fre-
quency for juveniles was 57%. The cut-
ting height of disc mowers increased to
100 mm increases harvest yields, reduces
wear on machinery, and decreases soil
erosion. A by-product of such a change
in cutting height is that turtle mortality
and injury rates should be reduced, as
Wood Turtle carapace height is < 87 mm.
Without changes in agricultural prac-
tices, this population will be extirpated.

Conserving New Zealand’s 
Diurnal Geckos

Visually cryptic, long-lived, diurnal
Green Geckos (Naultinus) were a signifi-
cant component of natural ecosystems
throughout much of New Zealand prior
to human settlement about 1800 years
ago. Since then, habitat modification and
introduced mammalian predators have
threatened many populations, making
their survival a conservation priority.
HARE ET AL. (2007. Journal of
Herpetology 41:81–93) pooled data col-
lected over a 25-year period on the pop-
ulation of N. manukanus on mammal-
free Stephens Island and determined that
it is female-biased (1:1.7), a trend evident
from birth, that sexual maturity occurs at
approximately four years of age, and that
71% of females reproduce annually.
These geckos are strictly diurnal, arbo-
real, and opportunistic thermoregulators.
Movements are limited, averaging 0.6 m
per day, characteristic of a sit-and-wait
foraging strategy. These data provide a
context for developing conservation
management plans for increasingly
threatened populations of geckos in the
genus Naultinus.

130 IGUANA  •  VOLUME 14, NUMBER 2  •  JUNE 2007 CONSERVATION RESEARCH REPORTS

Demographic differences between two island
populations of Komodo Dragons (Varanus
komodoensis) in Komodo National Park,
Indonesia emphasize the necessity for man-
agers of this priority conservation species to
develop island-specific management units.

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Populations of the Fijian Crested Iguana (Brachylophus vitiensis) were found on only four of 17
islands in western Fiji on which iguanas had been documented in the past.

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Marlborough Green Geckos (Naultinus
manukanus) on mammal-free Stephens
Island off New Zealand are visually cryptic,
long-lived, strictly diurnal, arboreal, and
opportunistic thermoregulators.

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Wood Turtles (Glyptemys insculpta) are vul-
nerable to common agricultural practices.

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