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GIANT BULLFROG PROJECT |
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GIANT
BULLFROG PROJECT OVERVIEW |
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| With the IUCN (World Conservation
Union) having listed the Giant Bullfrog (Pyxicephalus
adspersus) as “Near-Threatened” in
southern Africa, there is a need to conduct research
on this species (as a first step towards their
conservation), which has resulted in the inception
of a PhD research project at the University of
Pretoria (UP) in January 2003. During the course
of 2004 the research project transpired into the
official “Giant Bullfrog Project”
(GBP) of the Endangered Wildlife Trust (EWT).
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| Photograph by Martin Harvey |
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At present, the
GBP essentially embraces the research project being
conducted by UP PhD student Caroline Yetman. While Professor
Willem Ferguson (Director of the Centre For Environmental
Studies, Department of Zoology and Entomology, UP) is
supervising the academic progress of the PhD and the
EWT is overseeing management of the GBP within the realm
of the Trust. Plans to expand the activities of the
GBP will be formulated through the project steering
committee
The PhD research project will initially focus on the
central areas of Gauteng, which appear to harbour the
highest densities of Giant Bullfrogs in South Africa.
During the course of the research project four ecological
aspects of Giant Bullfrogs will be investigated including,
the geographic distribution, demography, genetics and
spatial habitat requirements of the species. The ultimate
outcome of the project will be the development of a
conservation management strategy for Giant Bullfrogs
to ensure the persistence of the species in Gauteng,
and the rest of South Africa. The research project is
planned to run until December 2006.
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GBP
RESEARCH COMPONENTS |
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Distribution study |
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As Giant Bullfrogs spend
most of the year in aestivation buried underground,
the distribution range of this species has remained
poorly described. The objective of this study
is to describe the geographic distribution range
of Giant Bullfrogs in South Africa as comprehensively
and as accurately as possible. This should provide
an improved platform on which a future conservation
management strategy for Giant Bullfrogs in South
Africa can be based. |
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Telemetry/Radio-tracking
study
Due to intense competition between different
forms of land-use in South Africa, which
is most marked in Gauteng, there is
an urgent need to secure portions of
land that are important for the long-term
survival of large populations of Giant
Bullfrogs. The objective of this study
is to investigate the movement patterns
and spatial habitat requirements of
Giant Bullfrogs. Results obtained from
this study will enable recommendations
to be made regarding the size, configuration
and connectivity of areas to be set
aside for the protection of viable populations
of Giant Bullfrogs. |
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A telemetry
unit to be implanted in a Giant Bullfrog.
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Mark-recapture study |
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Understanding
the dynamics of Giant Bullfrog populations is
crucial for appropriate in situ as well as ex
situ conservation management of the species (i.e.
management of the species in it’s native
environment, and in captivity, respectively).
However, very little is known about the structure
and functioning of Giant Bullfrog populations.
For instance, we have no idea about the sex ratio,
age structure, birth rates or loss rates of Giant
Bullfrog populations. The objective of this study
is to investigate the dynamics of Giant Bullfrog
populations using the technique of “mark-and-recapture”. |
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Measuring the body length
of a Giant Bullfrog |
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Genetic study |
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Since Giant Bullfrogs
breed in response to local rainfall, many
populations of this species probably breed
asynchronously. If asynchronous breeding
drives only local levels of movement and
dispersal, it may mean that Giant Bullfrog
populations exist more or less independently
from each other. The objective of this
study is to quantify the amount of genetic
variation between different populations
of Giant Bullfrogs in Gauteng. The results
of this study will dictate the geographic
scale of conservation actions on Giant
Bullfrogs, at least in Gauteng.
Results from all of the above-mentioned
studies will be used to formulate an effective
conservation management strategy for Giant
Bullfrogs in South Africa. |
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Electrophoresis
gel |
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For further information
in connection with Giant Bullfrogs please visit the
following website: www.giantbullfrog.org.
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The Giant Bullfrog
(Pyxicephalus adspersus) is the largest, and perhaps
most bizarre amphibian in southern Africa (males may
reach a body mass in excess of one kilogram). Unfortunately,
only when environmental conditions are conducive do
these frogs breed in large numbers. Prior to 2004, the
last known large-scale breeding event of Giant Bullfrogs
took place during 1992-1994. The reliance of this species
on specific environmental conditions makes it consequently
very susceptible to local extinction. In addition, the
apparent core of this species' distribution range lies
within Gauteng, which represents the current epicentre
of urban development in South Africa. Here, large tracts
of grassland and wetlands are increasingly being developed
into industrial or residential areas, leaving virtually
no undisturbed habitat. For these reasons the continued
survival of the Giant Bullfrog is in danger, at least
in Gauteng, but probably South Africa as a whole. At
present this species is listed by the World Conservation
Union (IUCN) as "Near-Threatened" in southern
Africa. Measures to protect Giant Bullfrogs are urgently
required to prevent the extinction of significant populations
of this species in southern Africa.
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GIANT
BULLFROG PROJECT: ACTIVITIES
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Distribution study |
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To improve current
maps of the geographic distribution range
of Giant Bullfrogs in South Africa, locality
records for this species will be prudently
obtained from: i) the Southern African
Frog Atlas Project (SAFAP); ii) specimens
kept in national and international natural
history museums; and iii) the “Giant
Bullfrog Survey,” which
represents an extremely unique opportunity
to obtain a large number of relatively
reliable locality records in a very short
period of time from potentially all parts
of South Africa. |
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Giant Bullfrog
Cartoon |
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The “Giant
Bullfrog Survey” requires people
from all across the country to kindly take photographs
of any bullfrogs that they encounter. The photographs
need to be submitted (by post or e-mail) together with
completed entry
forms (i.e. one entry form per locality).
The entry form requires participants to provide their
contact details, and various information pertaining
to their bullfrog sighting, including: date, time, place,
number of bullfrogs observed, etc. Fuji S.A. is donating
three digital camera awards for participants with the
best photo, best runner-up photo, and most unusual photo.
MTN is donating two Nokia cell phones for two Lucky
Draw entries. |
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Telemetry/Radio-tracking
study
Thirty Giant Bullfrogs will be implanted with
small telemetry units to enable estimation of
rates of immigration and emigration of individual
frogs between neighbouring populations, which
should indicate to what extent meta-population
dynamics and gene flow operate in the species.
Inspection of recorded movement patterns should
reveal what habitat conditions are favourable
or unfavourable for Giant Bullfrogs, and how
anthropogenic factors such as roads, walls,
electrical fences, exotic vegetation, livestock,
crop farming, and pollution influence the movements
and survival of these frogs. |
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A telemetry unit being
implanted into a Giant Bullfrog. |
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Mark-recapture study |
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For the purposes of this
study as many individual Giant Bullfrogs from
several different populations must be weighed,
measured, photographed and toe-clipped. Toe-clipping
is necessary to: i) mark each individual bullfrog
with a unique identification number; ii) obtain
a bone sample to age each frog using skeletochronology;
and iii) obtain a tissue sample to investigate
genetic variation between different bullfrog
populations. It is hoped that eventually population
size, sex ratio, age structure, natality, immigration,
loss rates and survival rates can be estimated
for each population of Giant Bullfrogs that
is sampled. |
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Throat-markings are
photographed for recognition of individual
Giant Bullfrogs |
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Genetic study |
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To quantify the amount of
genetic variation between different populations
of Giant Bullfrogs in Gauteng, at least 100 individual
bullfrogs from at least four different populations
will be toe-clipped to obtain a sufficient sample
size of tissue samples for DNA-sequencing. DNA
of an appropriate mitochondrial locus (comprising
~ 1, 000 base pairs) will be sequenced in the
forward and reverse directions. The final analysis
will be based on “Coalescence Theory”. |
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CONTACT
DETAILS FOR THE GIANT BULLFROG PROJECT |
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Caroline
Yetman
GBP Project Executant
University of Pretoria
Tel. (w): +27 (0) 12 420 4283
Tel. (c): +27 (0) 82 581 5453
Fax: +27 (0) 12 420 3210
E-mail: cayetman@zoology.up.ac.za |
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Prof.
Willem Ferguson
GBP Principle Investigator
University of Pretoria
Tel. (w): +27 (0) 12 420 2017
Fax: +27 (0) 12 420 3210
E-mail:
jwhferguson@zoology.up.ac.za |
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GIANT
BULLFROG PROJECT SPONSORS
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Rand Merchant Bank. |
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Rand Merchant Bank has generously sponsored
R48, 000.00 towards the GBP for 2004. |
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The Pretoria
East branch of the Hunters and Game Conservation Association
of South Africa. |
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Members of the
Pretoria East branch of the Hunters and Game Conservation
Association of South Africa have collectively donated
over R5, 000.00 towards the GBP for 2004. This is in
addition to them kindly committing themselves to providing
various services (e.g. electronic equipment repairs),
equipment, and field assistance for the GBP. |
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Arrow Bulk Marketing Ltd. |
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Managing directors
Pieter Kruger and Hilton Butler of Arrow Bulk Marketing
Ltd kindly sponsored a fuel card to cover Caroline Yetman’s
research-travelling expenses during the course of her
PhD.
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Click
here to read more about this project |
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