Download yesterday, today, tomorrow

The Mary
River turtle
yesterday, today, tomorrow...
Samantha Flakus and Marilyn Connell
1
Acknowledgements
Tiaro & District Landcare wish to gratefully acknowledge Sinclair Knight
Mertz who were official sponsor of the 2006 Queensland Landcare
Innovation Award. The prize money received from this award provided
financial assistance for this project.
We also wish to recognise Ergon Energy and staff for supporting
our chocolate turtle drives and the many other individuals who have
purchased our chocolates in recent years.
This booklet could not have been produced without the assistance
of the many people involved in its compilation. In particular, we wish
to thank John Cann for his wonderful photos and Julie Hinchliffe
for helping to pull everything together. Dr Col Limpus and staff from
QPWS deserve thanks for providing technical assistance for our
conservation project, as do all Project Officers and volunteers who
have assisted with the conservation of this turtle.
Thanks also to the many landholders, businesses and organisations
who have generously offered their assistance to the Mary River turtle
project over the years.
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3
Contents
Publication details
Published by Tiaro & District Landcare
Group Inc. Feedback welcome.
Web: www.maryriverturtle.com (or
www.mrccc.org.au/tiaro.html). Post:
PO Box 6, Tiaro QLD, Australia 4650
First edition September 2008.
ISBN 978-0-646-50067-6
Words by Samantha Flakus and Marilyn
Connell.
Cover, editing and design by Julie
Hinchliffe, Great Sandy Publications.
Photographs by Marilyn Connell except
where stated otherwise.
Map kindly produced and supplied by
Dale Watson, Mary River Catchment
Coordinating Committee (MRCCC).
MRCCC makes no representations
or warranties about its accuracy,
reliability, completeness and disclaims
all responsibility and all liability (including
without limitation, liability or negligence)
for all expenses, losses, damages
(including indirect or consequential
damage) and costs which might be
incurred as a result of the data being
inaccurate or incomplete in any way and
for any reason. This map is not to be
sold or re-made as part of a commercial
product.
Printed in Toowoomba, Australia by
Greenridge Press Pty Ltd on recycled
paper (9 Lives Silk Art).
Copyright text and images: © Tiaro
& District Landcare Group Inc. 2008.
No part of this publication may be
reproduced, transmitted, stored or
retrieved by any means without the
publisher’s prior permission.
4
About the authors
Samantha Flakus (above left) has been
a huge fan of the Mary River turtle since
she first began studying the species in
1997 as part of a Masters degree at the
University of Queensland. She spent her
teenage years growing up in Gympie
where she developed an appreciation for
the great outdoors - especially all things
aquatic. With the Mary River right on her
doorstep, Sam’s passion for turtles was
born. She sees writing this booklet as
the perfect way to educate young people
about one of Australia’s unique freshwater
turtle species, the Mary River turtle. When
she isn’t researching turtles, Sam enjoys
swimming, surfing and travelling.
Tiaro & District Landcare President
Marilyn Connell (above right) has
a twinkle in her eye whenever she
mentions the Mary River turtle... Like
many locals, Marilyn spent her youth
exploring Maryborough’s waterways
(but never heard of the turtle until she
met Samantha). Now an environmental
consultant, Marilyn has clocked up
18 years working in the environment
industry, 14 of which were spent with
Greening Australia. She feels strongly
about two things - observing ecological
processes in order to inform practical
restoration and management, and finding
the balance between conservation and
production. She has been coordinating
Tiaro Landcare projects for the past
10 years and loves nothing better than
working alongside community members,
researchers and professionals.
forward
6
introduction
8
yesterday
12
today
18
tomorrow
26
resources
32
5
Forward
these challenges? We are
proud to say our group draws its
inspiration from an ‘ambassador’;
a previously secretive, rarely-seen
local who is rapidly becoming one
of the most fascinating and likable
characters in this part of the world
- the Mary River turtle.
Tiaro & District Landcare members at a fencing working bee to protect nesting banks
(left to right / back row: Lynn Klupfel, Ray Klupfel and Adrian Ross, front row: Jan
Mortimer and Ron Black)
By Tiaro & District Landcare
“Inspired by the Mary River turtle”
is a fitting way to describe us.
Let’s face it - Landcare can be
a broad and tricky concept to
get our heads around. It tackles
everything from how we farm and
use our land/water resources,
to how we look after natural
ecosystems.
Our Landcare group is always
looking for ways to balance
6
production and nature
conservation. As well as looking
at the science, economics and
practicalities of land and water
management, we need to inspire
people with different values and
backgrounds to work together. At
times, it can be a real juggling act
and the answers are not always
as clear or straightforward as we
might like.
So how on earth do we meet
Tiaro & District Landcare first
formed in 1997. Back then, like
most people, we were ignorant of
the existence of the Mary River
turtle. Our habitat restoration work
along the river banks, however,
soon had us crossing paths with
Samantha Flakus (co-author of
this book). Samantha brought
us up to speed with the turtle’s
remarkable story of survival and
the research she’d just begun.
We were horrified, amazed
and inspired. Horrified by the
terrible (albeit unintentional)
pressure from humans forced
on this ancient creature in such
a short space of time; amazed
that the ‘embattled’ population of
turtles still lingered in our local
waterways; and inspired to ramp
up our Landcare efforts and do
the very best we could for the
Mary River turtle.
nests to increase the survival
of hatchlings. Among other
things, we also fund a support
scholarship for a post-graduate
student. Many landholders,
businesses and organisations
have generously offered us their
assistance. In fact, the success of
initiatives such as the chocolate
turtle drive continues to surprise
and delight us.
As you read through this booklet,
we invite you to explore the
knowledge of yesterday and
today, so that together, we can
look to protect the Mary River
turtle tomorrow and further into
the future. Like us, you may
experience feelings of horror,
amazement and inspiration.
We also invite you to take heart
from the fact that our efforts to
protect the turtle’s habitat and
life cycle are helping many other
native species at the same time.
Natalie Mathie (left) receives the Mary
River turtle support scholarship
By 2001, our turtle program was
formally underway. In the years
following, we have achieved
great things for Landcare in our
area by informing people about
this unique turtle and protecting
7
Introduction
T
he Mary River turtle, Elusor
macrurus, boasts a long and
interesting history of discovery.
Eluding scientists for almost thirty
years after its discovery in the
pet trade, this unique species
of Australian freshwater turtle is
now fascinating many students,
farmers and local folk. It has
become a local icon and was the
faunal emblem of the Tiaro Shire
Council.
natural environment has to offer.
Not all of us, however, have
fully come to grips with just how
diverse different species can be.
For many of us, a turtle is ‘just’
a turtle, and the same goes for
many other animals.
This resource has been compiled
to give you an insight into the life
of the Mary River turtle. It is aimed
at helping teachers, students and
biologists discover the true nature
of this secretive turtle. A guide to
current publications, websites and
resources is also provided.
Although there are many different
animals in the world, they all
form part of Kingdom Anamalia.
According to this system of
classification, animals are
grouped together based on their
similarities. They are divided into
two major groups depending
on whether or not they have a
backbone. Turtles belong to the
Chordates; those animals that
have a backbone.
And now, it is our pleasure to
introduce the Mary River turtle….
Mary River turtle
A turtle is ‘just’ a turtle…
or is it?
Many people in today’s society
are astounded by what our
8
Kingdom Anamalia
Phylum Chordata
Is this really true? Or is there
more to turtles than first meets
the eye? Let’s take a look at the
turtle’s family tree (opposite) to
find out more…
Turtles are further grouped into
Class Reptilia. Turtles share
this group with other reptiles
such as snakes, lizards and
crocodiles. As we progress down
the classification, turtles form
their own group known as Order
Testudines. The Testudines
include all turtles such as marine
turtles, freshwater turtles and land
tortoises. Australia is only home to
marine and freshwater turtles.
The freshwater turtle group is
Sub-Phylum
Vertebrata
Class Reptilia
(turtles, snakes, lizards etc)
Order Testudines
(marine turtles, freshwater
turtles & land tortoises)
Pleurodirans
Cryptodirans
(side-necked turtles)
(head withdrawn in an ‘S’ bend)
Chelidae
Carretochelydae
Side-necked turtles
Long-necked turtles
(4 genera & 24 species in Australia)
(1 genus & 6 species in Australia)
further split into side-necked
species that bend their neck to the
side when it is withdrawn or turtles
that withdraw their neck in an ‘S’
bend. The Mary River turtle is a
side-necked turtle.
You are probably beginning to
realise that turtles are not ‘just’
turtles. Their classification is
complex and based on many
physical and genetic features.
9
Introduction
Is it a turtle or a tortoise?
Generally speaking, all turtles that
live in water are known as turtles
and those that live on land are
tortoises. Tortoises have clublike feet and are slow moving.
Turtles have either flippers, like
marine turtles, or webbed feet like
freshwater turtles.
Mary River turtle (photo courtesy:
John Cann)
So, now that we know a little bit
about the ancestry of turtles, let’s
learn more about the Mary River
turtle.
How does the Mary River
turtle differ from other
turtles?
The Mary River turtle, Elusor
macrurus, is a short-necked
turtle which is assigned its very
own category or genus (Elusor).
Its unique characteristics set
it apart from all other species
of freshwater turtle worldwide.
As its name implies, the Mary
River turtle can only be found
in the Mary River Catchment in
southeast Queensland.
The Mary River turtle also
happens to be one of the largest
short-necked turtles in Australia.
The female’s shell grows to about
34cm in length, with the male’s
shell reaching up to 42cm. The
low-domed, streamlined shell is
dull in colour and unpatterned in
appearance. The underside of the
turtle’s body is cream to yellow
10
Tail of adult male Mary River turtle
in colour and the scales around
its feet, called the transverse
lamellae, are pink.
Faces of the Mary River. Left to right: Kreffts River turtle (Emydura krefftii), Snapping
turtle (Elseya albagula), Saw-shelled turtle (Elseya latisternum), not shown to scale
Mary River turtle (photo courtesy: Samantha Flakus)
Adult males and females differ
slightly in body shape. The
female’s shell is wider and
rounder at the back whereas the
male’s shell is depressed, narrow
and nearly straight-sided. Adult
males are also distinguished by a
large tail which extends to 70% of
the shell length when stretched.
(See photos for male / female
comparison on page 23).
11
Yesterday
The history and discovery of the Mary River turtle
19621974
Commercial egg harvest for the pet trade – identified and
sold as Elseya latisternum
1962
Through pet shop sales, the Mary River turtle (then known
as the ‘pet shop turtle’) was recognised as a unique and
new species by turtle enthusiasts
1970s Turtle enthusiast John Cann searches river systems
throughout Australia and Papua New Guinea to find
the origin of this ‘pet shop turtle’ without success
1974
Reptiles receive protection through the Queensland
Government’s introduction of the Fauna Conservation Act
- commercial egg harvesting becomes illegal
1984
The Victorian Government introduces laws to prevent
the sale of turtles under the size of 100mm in carapace
(shell) length – stopping the import of hatchlings
1987
John Cann re-establishes contact with pet shop
owners. He is given the supplier’s name – a fisherman
from Maryborough, Queensland
1990
Discovery of the ‘pet shop turtle’ in the Mary River, QLD...
The first Mary River turtle collected for identification was on
16 October 1990 by John Cann (Cann, 1998)
1994
The species is formally described as the Mary River
turtle, Elusor macrurus
1997
The nesting and reproductive patterns of the Mary River
turtle are studied by Flakus
1998
Study by Georges and McInnes to determine whether
temperature sex determination exists in the species...
Continued study by Flakus to learn more about other
aspects of the ecology of the Mary River turtle
2001-
Nests protected and monitored by Tiaro & District
ongoing Landcare with support from Greening Australia Qld
(WWF Threatened Species Grant) and Burnett Mary
Regional Group as part of the Queensland Parks & Wildlife
Service Turtle Conservation Project
20052007
12
Natalie Mathie from University of Queensland researches
the diving physiology of the Mary River turtle, impact of
oxygen levels and responses to predators
13
Yesterday
Let’s take a closer look...
1962 - 1974
Over a period of 12 years,
thousands of hatchling or
‘penny’ turtles were sold to pet
shops throughout Queensland,
New South Wales, Victoria and
Adelaide. During this time, these
penny turtles were thought to be
the common saw-shelled turtle
(Elseya latisternum). Little did
anyone know a new species was
about to be discovered…
Each year, up to 12,000 eggs
were collected from the banks of
the Mary River and incubated in a
backyard in Maryborough. As the
eggs hatched, the hatchling turtles
were shipped across the country
to supply the growing pet turtle
trade.
For the first couple of years,
hatchling turtles were sold to
suppliers for a mere 30c each.
The price then jumped to 50c
as demand increased. In the
local area from which the turtles
originated, it is said that hatchlings
were sold to the pet shops for $1
each.
Through the pet trade, the Mary
River turtle was discovered.
As the hatchlings grew, turtle
enthusiasts recognised that this
‘pet shop turtle’ was unique – this
was certainly no common sawshelled turtle.
14
During the time of commercial
egg harvest, it is thought that little
or no recruitment of hatchling
turtles back into the river occurred
around the Tiaro region. This was
because most of the eggs were
harvested.
1970s
In the 1970s, turtle enthusiast and
collector John Cann set out on a
mission to discover the origin of
the unidentified ‘pet shop turtle’.
Amongst turtle enthusiasts, the
species was referred to as ‘shortnecked alpha’. This is where John
Cann’s amazing story begins…
Mary River turtle hatchling
Saw-shelled turtle
John Cann – an inspiring
story of discovery
John Cann is a turtle enthusiast
and collector from the Sydney
region. His interest in freshwater
turtles has led him on some
amazing adventures across the
globe in search of new species.
He is well known in the ‘turtle
world’ for his discovery of ‘shortnecked alpha’ in its natural
habitat. Here’s an account of one
man’s incredible drive to solve an
age old mystery…
When John Cann first set off
to find out where ‘short-necked
alpha’ came from he was told
the Torres Strait. It was several
years before he convinced himself
this couldn’t be right. In 1974 he
sought the help of well-known
American biologist John Legler.
Cann would go on to search river
systems throughout Australia and
even Papua New Guinea, his
quest to discover and describe
the new species taking much
longer than he ever imagined.
Decades passed, yet there was
still no sign of ‘short-necked alpha’
in the wild. He was given several
false leads along the way – but
still he continued his search. By
1987, Cann re-established contact
with several pet-shop owners
and was finally given the name of
the supplier – a fisherman from
Maryborough in Queensland.
John Cann (photo courtesy: John Cann)
With the discovery of the turtle’s
origin in sight, Cann contacted
the supplier only to be led on
another wild goose chase – this
time throughout south-western
parts of Queensland, the Gulf,
Cape York and New South Wales.
It wasn’t until 1989 when Cann
met the supplier that the true
origin of ‘short-necked alpha’
was disclosed – the Mary River.
With poor diving conditions,
Cann still had no luck finding any
turtles; well not the type he was
after anyway. He began to doubt
whether ‘short-necked alpha’
really was from the Mary River.
In 1990, the Maryborough supplier
contacted Cann to say that he had
an adult turtle to show him. With
great haste, Cann made his way
to Maryborough to see this turtle.
Confirmed… it truely was an adult
‘pet-shop turtle’. Later that day on
the Mary River, Cann confirmed a
sighting of two adults basking. At
last, his search had ended!
(Adapted with permission from Australian
Freshwater Turtles by Cann, 1998)
15
Yesterday
1998
In 1998, Georges and McInnes
published their work on
temperature sex determination
in the Mary River turtle. They
discovered that, unlike marine
turtles, the Mary River turtle did
not rely on the temperature of
the sand during incubation to
determine the sex of the hatchling.
Turtle survey, November 2002
16
1997 - 2002
2001 - present
2005 - 2007
In 1997, Samantha Flakus, a
student from the University of
Queensland, began her study
on the Mary River turtle. Initially
investigating the species’ nesting
and reproductive patterns, the
study later expanded to look at
population dynamics, distribution,
abundance, diet and patterns of
movement.
Alerted to the plight of the
endangered turtle, Greening
Australia and Tiaro & District
Landcare members commenced
work aimed at increasing the
species’ survival prospects.
Activities include protecting nests,
mapping nesting sites, raising
awareness of the Mary River turtle
and funding a support scholarship
for a tertiary student. Without nest
protection in the Tiaro reach of the
river, it is believed 90 – 100% of
all nests laid would be raided by
predators - mostly goannas, foxes
and domestic and wild dogs.
Natalie Mathie researches
how changes in environmental
conditions as a result of river
damming may influence the
aquatic respiration and diving
behaviour of hatchling turtles.
Samantha Flakus takes hatchling
measurements
Fencing to protect nests from goannas,
foxes, wild dogs and cattle
17
Today
H
aving remained undiscovered
for so many years, the Mary
River turtle is now attracting the
attention of scientists eager to
learn more about its biology and
ecology.
Over the last 10 years we have
learnt a lot about the Mary
River turtle and how it uses its
environment. We have discovered
how widely the turtles are found,
which habitat they prefer, what
they like to eat, where they like
to swim and lay their eggs, how
often they reproduce and how
long they can dive for. Yet despite
this wealth of knowledge, there is
still much more to learn.
Ongoing research has been
established through a number of
programs and specific projects
are undertaken through university
studies.
Current legal status
The Mary River turtle is listed
as an ‘Endangered’ species
under Australian Government
and Queensland Government
legislation. It is also recognised as
such by the IUCN (International
Union for Conservation of Nature
and Natural Resources).
In 2003, the International Turtle
Conservation Fund included the
Mary River turtle in its list of the
world’s 25 most endangered turtle
species.
18
Secrets revealed...
Let’s explore what we do know
about the life of this unique
species and how it interacts with
its environment.
Distribution and habitat
The Mary River turtle is endemic
to the Mary River in southeast
Queensland (see map opposite).
It is found throughout the
mainstream of the Mary River
from Kenilworth in the upper
reaches, to the saltwater tidal
barrage downstream of Tiaro. It
may also occur in some of the
major creeks.
The Mary River turtle’s in-stream
habitat is varied, but generally
the turtles are found in welloxygenated waters around riffle
zones. They are often found
hiding under log jams, rock
crevices or water plants and
can often be spotted basking on
logs or rocks protruding from the
water. Juvenile turtles are more
commonly found around rocky
outcrops and are rarely seen
basking.
The Mary River turtle’s preferred
nesting habitat is unvegetated
sand banks.
19
Today
Movement patterns
Like sea turtles, the Mary River
turtle seems to be faithful to its
feeding grounds and will return
to the same pool after moving
away for breeding or during
flooding events. During the nonbreeding season, the movements
of both male and female Mary
River turtles are very localised
(200-600m). However during the
breeding season, females can
swim up to 2km to find a suitable
sand bank on which to lay their
eggs. Males also make large
movements of up to 1.1km during
the breeding season - presumably
to find female turtles with which to
mate.
During flooding events, Mary
River turtles swim upstream
against the current to find an
area out of the main flow of the
floodwaters. As soon as the flow
of the water drops back down to
normal levels, the turtles move
Male Mary River turtle with radio tracking
device attached to its shell (photo
courtesy: Samantha Flakus)
20
back to the same pool from which
they originated.
This type of behaviour reduces
their chances of being washed
downstream with the current of
strong flood waters.
Nesting and incubation
Although the species is unique
in many ways, its nesting
habits are probably what have
intrigued scientists the most.
Historical records suggest Mary
River turtles congregate around
sand banks during the nesting
season and nest en masse at
night after the first significant
summer rain. Commercial egg
collectors witnessed these events
back in the 1960s and 1970s.
Unfortunately, with breeding
numbers much lower than what
they used to be, mass nesting
has not been observed in recent
times.
Nesting occurs from October to
Mary River turtle eggs in nest
January each year, with most of
the nesting occurring in November
and early December. Scientists
suggest Mary River turtles breed
every year and only produce one
clutch of approximately 13 eggs.
Incubation generally takes up to
50 days, however this depends
on the temperature of the sand.
Cooler temperatures extend the
incubation period, while warmer
temperatures speed up the
process. Not all nests make it to
full term because of predation
and flooding. For those that do
survive, hatching success is
generally high.
Predation of the eggs by feral
dogs, foxes and goannas is a
big problem for the Mary River
turtle. Since 2001, Tiaro Landcare
officers have been protecting
nesting banks and individual nests
in an effort to help hatchlings
repopulate the river.
a combination of electric and
mesh fencing, while individual
nests are protected using flat
plastic mesh screens. Since the
project began, the Landcarers
have protected up to 76 nests
each year and helped a total
of 1,500+ eggs develop into
hatchlings. Although encouraged
by the results, we are mindful
that today’s population has a very
long way to go if it’s to approach
previous levels (as suggested
by the 10-15,000 hatchlings sold
each year during the pet trade).
Weather conditions also impact on
the success of nests. If the nest
is inundated by floodwaters, the
partially-developed hatchling dies.
Hatchlings are about 3.3cm long
and weigh approximately 6.8g.
Nesting banks are protected using
Mary River turtle egg
Mary River turtle hatchling
21
Today
Diet
As a juvenile, the Mary River turtle
mainly eats insect larvae and
freshwater sponges which are
generally found in shallow rocky
areas. Studies have shown that a
diet rich in protein and calcium is
needed by young turtles for rapid
growth and shell hardening.
As the Mary River turtle
matures, its diet shifts to a more
herbivorous one comprising
mainly water plants. Not fussy
about the ‘type’ of plant they
eat, the turtles will generally eat
whatever is available. Along
with plant material, they ingest
insect larvae (probably belonging
to insect species which have a
preference for laying their eggs
among the aquatic plants). There
are reports of turtles feeding on
freshwater mussels and some
terrestrial plant materials.
Population dynamics
From 1997–1999, a markrecapture program undertaken
in the river upstream of Tiaro
looked at the structure of the
Mary River turtle population. The
study revealed a population which
wasn’t very healthy, as very few
sub-adult or teenage turtles were
present. As the graph opposite
shows, the population was mainly
comprised of adult turtles and a
small number of juveniles.
22
It’s thought the Mary River
turtle may take about 30 years
to mature (that is, become a
breeding adult). The absence of
sub-adult turtles in the population
may therefore be a result of the
intensive egg harvest of the 1960s
and 1970s.
Even though egg harvesting no
longer occurs, the high incidence
of egg predation by goannas and
foxes seems to be keeping the
juvenile population low.
Another interesting observation
made during the study was the
distinct difference in size between
adult female and male Mary
River turtles. Whereas female
turtles grow to about 32cm, the
much-larger males reach about
42cm. Tail length is also markedly
different between the sexes; male
tails are about 14cm in length
whereas female tails only reach
about 3.5cm.
Graph 1: Age structure of the Mary River turtle population (1997-1999)
(graph courtesy: Samantha Flakus)
Mary River turtle (photo courtesy: John Cann)
Undersides of male (right) and female
Mary River turtles showing difference in
tail size (tail end is bottom of photo)
23
Today
Diving behaviour
Some species of freshwater
turtles, including the Mary River
turtle, are able to extract oxygen
from the water just like fish.
These turtles have special gilllike structures in their tails called
cloaca bursae. As water is flushed
in and out of these structures, the
turtles are able to absorb oxygen
from the water. This special ability
allows the turtles to outlast other
freshwater turtles underwater.
By studying the diving behaviour
of the Mary River turtle, scientists
have discovered that hatchling
Mary River turtles can remain
underwater for as long as 2.5
days without coming to the
surface to breathe air. The length
of time that the turtles can remain
submerged depends on a number
of factors such as the water
temperature, oxygen level, water
flow and depth. Changes in these
environmental conditions have
serious implications for the turtle.
In what ways do you think
a turtle’s environment might
change? What could trigger these
changes?
eels, large fish, and herons and
raptors. Predators can strike when
hatchling turtles are swimming
within the water column or at the
water’s surface.
The hatchling Mary River turtles
have a way around this… In
the presence of a predator,
they are able to increase their
submergence time by 35%. Fewer
trips to the surface to breathe
in oxygen and more time spent
hiding on the river bed means
less exposure to predators. But
what happens if oxygen levels
in the water change? Consider
this… when oxygen levels in the
water are low, hatchlings turtles
are unable to respire aquatically.
They have been found to spend
20% more time at the surface to
breathe, thereby increasing their
exposure to predators.
Top: Mary River turtle hatchling making its
way to the water
Bottom: The Mary River showing riffle
zone (where shallow water flows over
rocks or debris in rapid turbulent flow)
Responses to predators
As with most animals, hatchling
turtles experience the highest
mortality of any life stage.
Generally, this is due to predation
from animals such as water rats,
24
25
Tomorrow
M
any conservationists and
scientists are deeply
concerned for the future of the
Mary River turtle. ‘Endangered’
status obligates the Australian and
Queensland Governments to plan
and implement recovery actions.
The IUCN perceives a high risk
of extinction in the wild in the
near future. Declining numbers of
mature individuals and the turtle’s
dependency on a single location
(the Mary River) heighten the
species’ vulnerability.
Over the last 30 years, the
Mary River turtle population has
plummeted, presumably as a
result of human harvest, loss
of nesting habitat, increased
predation by both native and
exotic species and environmental
degradation. The number of wild
turtles is not known, however
estimates indicate that the number
of breeding females has dropped
by 90% since the 1960s.
Rubbish collected by
floodwaters
It may take decades for the full
extent of these impacts on the
turtle to be fully realised. Like the
Australian lungfish, adult turtles
can live a long time; up to 80
years.
Habitat choked by water
hyacinth (a water weed)
26
The Mary River at dawn
We may not know everything
about the Mary River turtle, but we
do know enough to realise that its
long term survival hinges on the
way we look after the environment
in which they live.
Impacts on the Mary
River turtle
Let’s take a look at some of the
impacts the Mary River turtle is
currently faced with and explore
some of the ways in which we can
help the species to survive…
Dams and weirs
In today’s modern world, one of
the major impacts facing some
freshwater turtle populations is the
alteration of their habitat through
the construction of dams and
weirs. Have you ever stopped to
think about what sort of changes
these dams and weirs are having
on the river environment?
Dams and weirs alter the natural
flow of a river to trap water for
later use. Apart from the obvious
changes to the immediate
area of the structure, there are
other more significant changes
occurring instream which, in
turn, create problems for the
myriad of creatures inhabiting
this environment. Some of these
changes include:
Increased water levels
Altered water temperature
Decreased oxygen levels
Decreased water clarity
Decreased plant life
Altered instream habitat
Altered transportation of
sediment
27
Tomorrow
For some species, these changes
result in an environment which is
uninhabitable.
For the Mary River turtle, a
species unable to adapt to such
changes, this means trouble.
Take a look at the changes to its
habitat which result from altering a
flowing river to a large, stationery
pond such as a dam:
No in-stream habitat such
as log jams and plant life
where the Mary River
turtle can shelter;
Flooding of sand banks
that could have been used
for nesting – no place now
to lay eggs;
No plant life because the
water is too dirty, there
is less oxygen and it is too
deep – no food for the
Mary River turtle to eat;
Poor water quality and
less oxygen in the water
– conditions unsuitable for
the Mary River turtle‘s
survival.
Predation
Nest destruction by goannas,
foxes and wild dogs is also a
major problem today, resulting
in low levels of hatchling
recruitment back into the wild
population. Extended periods of
low recruitment, together with
28
low breeding rates and slow
maturity, will all substantially affect
the Mary River turtle’s ability to
survive.
Habitat modification
What can we do to help?
What actions we can take to help the Mary River turtle survive?
Apart from the construction of
dams and weirs, there are other
human activities that dramatically
change the physical and chemical
balance of a river system. Land
clearing, sand mining, agricultural
and industrial run-off and
sewerage discharges all affect
the natural balance of such a
system. These changes can be
as detrimental to aquatic plants
and animals as the other impacts
already listed.
1. Protect our river banks from clearing and regenerate alreadycleared banks using native plants;
David Parkes lays down mesh to protect
a turtle nest from predators
7. Report any tagged turtles you find to your local QPWS office to
assist researchers in learning more about the Mary River turtle;
2. Fence turtle nesting sites to protect nests from cattle
trampling;
3. Exclude sand extraction from nesting banks;
4. Remove weeds from known sand banks to allow for turtle
nesting; remove water weeds (eg water hyacinth and salvinia) as
these deplete oxygen, light and temperature;
5. Seek advice on how to protect turtle nests by contacting your
local Landcare or Queensland Parks & Wildlife Service (QPWS)
office;
6. Be water-wise and become self sufficient in water use so as not
to encourage the construction of dams and weirs in your area;
8. Do not pollute our waterways with rubbish and other waste;
9. Know what to do if a turtle is caught on your fishing line - cut
the line close to the mouth of the turtle if the hook cannot be easily
removed;
10. Never use stainless steel hooks when fishing as they do not
degrade;
11. Reduce chemical use on farms or use bio-degradable
chemicals that are not harmful to the environment;
12. Learn more about protecting the world you live in – remember
you share this planet with other living things.
Positive action, together with ongoing research and monitoring,
is needed if this unique population of turtles is to
survive in our waterways.
29
Tomorrow
Last word
The Mary River turtle’s story of
survival is an incredible one.
As part of its evolutionary journey
over millions of years, the species
has survived all of the challenges
nature has thrown at it. It has
adapted and improved in ways
we may never fully understand.
Yet in just a few short decades,
human beings forced the turtle
to endure its greatest onslaught
of challenges yet. That the Mary
River turtle somehow managed
to pull through gives our own
species a chance to put things
right.
community doing its best to create
a sustainable environment for all
species, we are optimistic that
yesterday’s mistakes have taught
us valuable lessons.
Together, we can act in positive
ways to help the Mary River
turtle today, giving this wonderful
creature the best chance of a
bright future tomorrow.
Tanzi Smith releases hatchlings
People’s attitudes are changing at
an encouraging rate, with younger
generations in particular quick to
embrace the turtle as a symbol
of conservation and a fascinating
species in its own right.
As researchers and Landcarers,
we still have much to learn,
including why the species calls
the Mary River home and is found
nowhere else in the world. At the
same time, more and more people
are coming to grips with the
urgent need for both habitat and
species protection in order for this
turtle to survive in the wild.
The authors and Tiaro & District
Landcare sincerely hope this
booklet has helped to inspire and
inform its readers. As part of a
30
31
Resources
Publications
Johnson, D. 1997. State of the rivers: Mary River and major tributaries;
an ecological and physical assessment of the condition of streams
in the Mary River Catchment. Department of Natural Resources,
Resource Sciences Centre, Brisbane.
Cann, J. 1998. Australian Freshwater Turtles. Beaumont Publishing Pty
Ltd. Singapore.
Pointer, S.M. 1998. Land Resource Bulletin – Land use, vegetation
cover and land disturbance survey of the Mary River Catchment, 1997.
Queensland Government.
Bridges, E.M., Ross, D.J. and Thompson, C.H. 1990. Soils of the
Mary River alluvia near Gympie, Queensland. CSIRO Division of soils,
Adelaide.
Cann, J. and Legler, J. 1994. The Mary River Tortoise: a new genus
and species of short-necked Chelid from Queensland, Australia
(Testudines:Pleuroduria). Chel. Cons. Biol., 1(2):81-96.
Clark, N.J. 2008. The diving physiological ecology of Australian
freshwater turtle hatchlings. PhD Thesis, The University of
Queensland.
Clark, N.J., Gordos, M.A. and Franklin, C.E. 2008. Thermal plasticity
of diving behaviour, aquatic respiration and locomotor performance in
the Mary River Turtle Elusor macrurus. Physiological and Biochemical
Zoology 81 (3):301-309.
Clark, N.J., Gordos, M.A. and Franklin, C.E. 2008. Diving behaviour,
aquatic respiration and blood respiratory properties: a comparison of
hatchling and juvenile Australian turtles. Journal of Zoology. 275:399406.
Cogger, H.G. 2000. Reptiles and Amphibians of Australia 6th edition.
Reed New Holland Sydney.
Connell, M. and Wedlock, B. 2006 Mary River Turtle Protection:
Tiaro District of Southeast Queensland, 2005 2006 nesting season,
Conservation technical and data report, Volume 2006 Number 8 Qld
Environmental Protection Agency.
Queensland Government (2005) Nature Conservation (Wildlife)
Regulation 1994 Schedule 2 Office of the Queensland Parliamentary
Counsel, Brisbane.
Van Kampen, T., Emerick, S.P. and Parkes, D. 2003. Increasing the
Survivorship of the Mary River Turtle. Tiaro District of Southeast
Queensland October 2002 - March 2003. Unpublished Report,
Greening Australia, Tiaro and District Landcare Group Inc. and
Queensland Parks and Wildlife Service.
Wilson, S. 2005. A field guide to Reptiles of Queensland. New Holland.
Websites
www.iucnredlist.org/ - International Union for Conservation of Nature
and Natural Resources
www.austmus.gov.au – Australian Museum
www.environment.gov.au - Australian Government Department of the
Environment, Water, Heritage and the Arts
www.qm.qld.gov.au/features/endangered/ - Queensland Museum
www.epa.qld.gov.au/nature_conservation/wildlife/native_animals
- Queensland Government Environmental Protection Agency
Flakus, S.P. 1998. Reproduction, population dynamics and movement
patterns of the Mary River turtle, Elusor macrurus. Unpublished thesis.
www.uq.edu.au - The University of Queensland
Flakus, S.P. 2002. Ecology of the Mary River turtle, Elusor macrurus.
Masters thesis, The University of Queensland.
www.aftcra.org.au – Australian Freshwater Turtle Conservation
Research Association
Georges, A. 1995. Mary River Turtle. Australia Nature Summer
1995/6:22.
Georges, A. and McInnes, S. 1998. Temperature fails to influence
hatchling sex in another genus and species of chelid turtle, Elusor
macrurus (Chelonia:Chelidae). J. Herptetol. 32(4): 596-598.
32
www.mrccc.org.au/tiaro.html - Tiaro & District Landcare
MARY RIVER TURTLE WEBSITE
Great news! Tiaro & District Landcare is creating a
new website solely dedicated to the Mary River turtle.
Visit www.maryriverturtle.com
33
Contacts
For more information on current
research on the Mary River
turtle contact the following
organisations:
Tiaro & District Landcare
Address: PO Box 6, Tiaro Qld
4650, Phone: (07) 4129 6206
Queensland Government
Environmental Protection
Agency / Queensland Parks &
Wildlife Service
EPA Customer Service Centre:
PO Box 15155, City East Qld
4002, Phone: 1300 130 372.
EPA Maryborough: PO Box 101,
Maryborough Qld 4650, Phone:
(07) 4121 1800. EPA Mon Repos:
141 Mon Repos Rd, Mon Repos
Qld 4670, Phone: (07) 4159 1652
The University of Queensland
Address: Integrative Biology
School, The University of
Queensland, Brisbane Qld 4072,
Phone: (07) 3365 1111
34
Mary River Catchment
Coordinating Committee
Address: PO Box 1027, Gympie
Qld 4570, Phone: (07) 5482 4766
The parts of a turtle
Barbel - soft fleshy skin
protuberances, believed to be
sensory in function on the chins of
some turtles
Carapace - the upper half of the
shell of turtles
Cloaca - the chamber into
which the digestive, urinary and
reproductive organs empty
Cloaca bursa - a protective sac
of fluid shielding the communal
excretory cavity
Plastron - the lower half of the
shell
Only a few parts are listed here as
defined by Cann (1998).
Mary River turtle hatchling (photo
courtesy: John Cann)
35
Proceeds from the sale
of this booklet assist
Tiaro & District Landcare
in its efforts to save the
endangered Mary River
turtle. Visit us online at
www.maryriverturtle.com