Last year
saw the completion of an Australian Research Council funded
collaborative research project involving the Bawinanga Aboriginal
Corporation (BAC), Djelk Rangers and the Institute for Applied
Ecology (University of Canberra). The project was successful in
providing the fundamental knowledge and understanding to underpin
sustainable harvests of C. rugosa eggs and adults
in the Maningrida region.
Indigenous
communities in northern tropical Australia have used northern
snake-necked turtles (Chelodina rugosa) as a
significant source of food for generation upon generation. They
have developed a wealth of knowledge of C. rugosa
and how they can be sustainably utilised for subsistence. BAC has
been keen to see this knowledge put to use in developing a local
industry which contributes to economic self-sufficiency while at
the same time maintaining and reinforcing links to indigenous
culture. The harvest and incubation of C. rugosa
eggs and the sale of hatchlings into the local (NT) pet industry
provides such an opportunity.
Compared
to other freshwater turtles, C. rugosa are fast
growing, reach a breeding age quickly and lay multiple clutches of
eggs per year. Our research shows that these life-history traits,
in conjunction with density limited hatchling recruitment and local
harvest practices, are responsible for the continued persistence of
C. rugosa over the long period of interaction with
people in northern tropical Australia.
Although
subsistence harvesting in the Maningrida region appears
sustainable, people today are finding it harder to locate turtles.
This is not because of cultural changes to meet contemporary
circumstances, but rather, because feral pigs deplete turtle
populations immediately prior to harvesting. Projective models
indicate that predation by pigs will almost certainly lead to the
local extinction of C. rugosa in most savannah
billabongs in the Maningrida region within 50 years
time.
On a more
positive note, modelling also shows that if a multi-faceted
approach to pig management (including fencing of billabongs,
periodic culling and restocking with juvenile turtles) is adopted,
C. rugosa can continue to be harvested without
threatening local population persistence. In fact C.
rugosa could be harvested for commercial purposes if pigs are
appropriately managed. This discovery has the potential to
transform present approaches to turtle conservation and
management.
On ground
training has played a critical role in the project. Djelk Rangers
and some community members now possess the necessary skills to
detect and quantify contemporary threats to turtle abundance, and
to harvest and incubate C. rugosa eggs and care for
subsequent hatchlings. Importantly, the research has provided a
management tool to support judgements on appropriate levels of
exploitation in support of indigenous harvests.
Over the
next couple of years the BAC Djelk Rangers will continue to
collaborate with western scientists, to examine the economic,
cultural and environmental benefits of several approaches for
managing feral pigs and, in turn, conserving C.
rugosa. We will keep you updated with our progress.
For
further information, or publications arising from this work,
contact:
Ben
Corey
Bawinanga Aboriginal Corporation
PMB 102 Winnellie, NT 0822
Tel: 08
8979 5460
Email: wildlife@bawinanga.com
or
Dr Damien
Fordham
Research Institute for Climate Change and
Sustainability,
School
of
Earth and
Environmental Sciences,
The University of Adelaide, SA 5005
Tel: 08
8303 6711
Email: damien.fordham@adelaide.edu.au
