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IGUANA  •  VOLUME 15, NUMBER 3  •  SEPTEMBER 2008 177CONSERVATION RESEARCH REPORTS

Non-native Fishes Threatening
Hellbenders in Missouri

The introduction of non-native fishes
often results in the local extinction of
native amphibians due to a lack of evolu-
tionary history and resultant minimally-
adapted antipredator behaviors toward
the introduced fishes. Populations of
Hellbenders (Cryptobranchus alleganien-
sis) in Missouri have declined consider-
ably since the 1980s, coinciding with a
rapid increase in non-native trout intro-
ductions for recreational angling. GALL

(2008. Unpubl. M.S. Thesis, Missouri
State University, Springfield) examined
Hellbender and fish predator-prey inter-
actions by: (1) examining the foraging
behavior of predatory fishes in response
to a Hellbender secretion; (2) comparing
the number of secretion and control-
soaked food pellets consumed by trout;
and (3) comparing the response of larval
Hellbenders to chemical stimuli from
introduced (trout) and native fish preda-
tors. Brown Trout, Walleye, and large
Banded Sculpins responded to
Hellbender secretions with increased
activity, whereas small Banded Sculpins
responded by decreasing activity. In addi-
tion, Brown Trout ingested more
Hellbender secretion-soaked food pellets
than control pellets, whereas Rainbow
Trout expelled secretion-soaked food pel-
lets. Finally, larval Hellbenders exhibited
weak fright behavior in response to
chemical stimuli from nonnative trout
relative to their responses to native preda-
tory fish stimuli. These combinations of
responses indicate that predation by non-

native fishes may be a plausible hypothe-
sis for the decline of Hellbender popula-
tions in Missouri.

Effects of Converting Dry Tropical
Forest to Agricultural Mosaics

SUAZO-ORTUÑO ET AL. (2008. Conserva-
tion Biology 22: 362–374) explored the
impact of forest conversion to agricul-
tural mosaic on anuran, lizard, snake,
and turtle assemblages in Neotropical dry
forests. Over two years, the authors sam-
pled six small watersheds on the western
coast of Mexico, three conserved and
three disturbed. The disturbed water-
sheds were characterized by a mosaic of
pastures and cultivated fields (corn,
beans, squash) intermingled with patches
of different successional stages of dry for-
est. In each watershed, they conducted
11 diurnal and nocturnal time-con-
strained searches in ten randomly estab-
lished plots. We considered vulnerability
traits of species in relation to habitat
modification. Eighteen anuran, 18 lizard,
23 snake, and three turtle species were
recorded. Thirty-six species (58%)
occurred in both forest conditions, and
14 (22%) and 12 species (19%) occurred
only in the conserved and disturbed sites,
respectively. Assemblages responded dif-
ferently to disturbance. Species richness,
diversity, and abundance of lizards were
higher in disturbed forests. Anuran diver-
sity and species richness were lower in
disturbed forest, but abundance was sim-

ilar in both forest conditions. Diversity,
richness, and abundance of turtles were
lower in disturbed forest. The structure
and composition of snake assemblages
did not differ between forest conditions.
Species were considered disturbance-sen-
sitive if their abundance was significantly
less in disturbed areas. Four anuran
(22%), two lizard (11%), and three tur-
tle (100%) species were sensitive to dis-
turbance. No snake species was sensitive.
The decline in abundance of distur-
bance-sensitive species was associated
with the reduction of forest canopy cover,
woody stem cover, roots, and litter-layer
ground cover. Anuran species with small
body size and direct embryonic develop-
ment were especially sensitive to forest
disturbance. An important goal for the
conservation of herpetofauna should be
the determination of species traits associ-
ated with extinction or persistence in
agricultural mosaics.

Reptilian Road Mortality 
in Illinois

Roads have numerous negative ecological
effects on terrestrial fauna, and vehicular
mortality can have significant demo-
graphic consequences for some species.
SHEPARD ET AL. (2008. Copeia 2008:
350–359) studied road mortality of rep-
tiles around Carlyle Lake, Clinton
County, Illinois, USA, from April 2000
through November 2002, to assess the
impact of vehicular traffic and identify

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

Populations of Hellbenders (Cryptobranchus
alleganiensis) in Missouri have declined con-
siderably since the 1980s, coinciding with a
rapid increase in non-native trout introduc-
tions for recreational angling. 

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Ameiva undulata (illustrated) and Sceloporus utiformis were the only two sampled species of
lizards that were disturbance-sensitive. Both are terrestrial and forage in the leaf litter. Reduction
of the litter may be responsible for the decline of these species in disturbed forests. 

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178 IGUANA  •  VOLUME 15, NUMBER 3  •  SEPTEMBER 2008 CONSERVATION RESEARCH REPORTS

influential factors. Carlyle Lake, a popu-
lar tourism/recreation area, is situated in
a larger agricultural landscape and is
home to the largest Illinois population of
the endangered Eastern Massasauga
(Sistrurus catenatus). The authors docu-
mented 321 cases of reptilian road mor-
tality (84 individuals of six turtle species
and 237 individuals of nine snake
species) while driving the approx. 46-km
study route roundtrip daily. Turtle road
mortality was highest in May and June,
and positively associated with precipita-
tion and minimum daily temperature.
Colubrid snake road mortality was high-
est in April and October, and positively
associated with minimum daily temper-
ature. We recorded 42 cases of road mor-
tality of S. catenatus, with the highest
number occurring from mid-August to
mid-September. Road mortality in S.
catenatus was biased toward adult males,
which show an increase in movement in
August, coinciding with the peak of the
mating season and a period of high
tourist visitation. The traffic intensity on
a road segment did not significantly
affect the level of road mortality, but seg-
ments through high-quality habitats had
higher levels of mortality than segments
through lower quality habitats.

Refutation of Traditional Chinese
Medicine Claims about Turtles

The Chinese turtle trade is the primary
threat to endangered turtle populations
throughout Asia, primarily because of the
long tradition of consuming turtles in
China. Practitioners of Traditional
Chinese Medicine (TCM) promote
nutritional and medicinal benefits from
eating turtles, especially hardshell species.
MEILING ET AL. (2008. Applied
Herpetology 5: 173–187) tested these
claims by determining the nutritional
value of turtle products (meat, fat and
shell) in five species of geoemydid turtle,
Cuora trifasciata, C. mouhotii, Mauremys
mutica, M. sinensis, and Geoemyda speng-
leri. The authors analyzed nutritional vari-
ables such as the composition of amino
acids, fatty acids, and mineral elements to
determine the relative nutritional quality
of turtle products. Their study refutes
TCM claims about products made from
hardshell turtles. Alternative animal prod-
ucts should be substituted to obtain sim-
ilar minerals, amino acids and fatty acids.
Balancing the cultural use of turtles with
their conservation status remains a major
challenge.

A Sixth Mass Extinction?
Many scientists argue that we are either
entering or in the midst of the sixth
great mass extinction. Intense human
pressure, both direct and indirect, is hav-
ing profound effects on natural environ-
ments. The amphibians — frogs, sala-
manders, and caecilians — may be the
only major group currently at risk glob-
ally. A detailed worldwide assessment
and subsequent updates show that one-

third or more of the 6,300 species are
threatened with extinction. This trend is
likely to accelerate because most
amphibians occur in the tropics and
have small geographic ranges that make
them susceptible to extinction. The
increasing pressure from habitat destruc-
tion and climate change is likely to have
major impacts on narrowly adapted and
distributed species. WAKE AND

VREDENBURG (2008. Proceedings of the
National Academy of Sciences 105:
11466–11473) showed that salamanders
on tropical mountains are particularly at
risk. A new and significant threat to
amphibians is a virulent, emerging infec-
tious disease, chytridiomycosis, which
appears to be globally distributed, and its
effects may be exacerbated by global
warming. This disease, which is caused
by a fungal pathogen and implicated in
serious declines and extinctions of >200
species of amphibians, poses the greatest
threat to biodiversity of any known dis-
ease. The authors’ data for frogs in the
Sierra Nevada of California show that
the fungus is having a devastating
impact on native species, already weak-
ened by the effects of pollution and
introduced predators. A general message
from amphibians is that we may have lit-
tle time to stave off a potential mass
extinction.

Road mortality of the endangered Eastern
Massasauga (Sistrurus catenatus) was biased
toward adult males, which show an increase
in movement in August, coinciding with the
peak of the mating season and a period of
high tourist visitation.

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Analysis of turtle meat from five species of
Chinese turtles, including Cuora trifasciata,
refuted claims about the nutritional value of
eating hardshell turtles.

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Amphibian population declines, extirpa-
tions, and extinctions may be the first sign of
an impending mass extinction. The status of
the critically endangered Mountain Yellow-
legged Frog (Rana muscosa) may be a harbin-
ger of other declines in the United States.

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