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Volume 27 Issue 3
October 2013
ISSN No. 1322-9028
Newsletter of the
Australasian Wildlife Management Society
General Inquiries:
President
Peter Fleming
[email protected]
General Inquiries
Lyn Nelson
[email protected]
Membership
Tarnya Cox
[email protected]
Newsletter editor
Cheryl Krull
[email protected]
AWMS Conference enquiries
On Q Conference Support
T: +00 61 2 6161 9024
[email protected]
Inside this issue:
Keeping track........................................................1
Presidential Mutters.......................................2-4
AWMS AGM Notice.............................................4
The impact of invasive cane toads on
native wildlife communities: Project
Kimberley...........................................................5-7
When aliens replace natives: impacts
of black rats (Rattus rattus) in the
Sydney Harbour National Park...................8-9
AWMS Committee positions for
nomination and election..................................9
Wild Supply Advertisement.......................... 10
AWMS Conference Notice............................. 11
This newsletter reflects the opinions
of the author(s) but not necessarily
those of the AWMS Committee or
membership. AWMS makes no claim
as to the accuracy of stated claims
and any party using this information
does so at their own risk.
Keeping track
Adapted from http://www.stuff.co.nz/business/unlimited/8911024/Keeping-track- By Kim Triegaardt
Dr Helen Blackie, Associate Director of Lincoln University’s Centre for Wildlife Management and
Conservation [email protected]
New Zealand conservation services spend
millions of dollars annually on protecting
native flora and fauna. With more than 40%
of pre-human bird species now extinct, the
proportion of birds classed as threatened in
New Zealand is one of the world’s highest.
Campaigns to eradicate pests such as stoats
and weasels are costly in time and resources
and one of the biggest issues for conservation
authorities is figuring out what pests are
present in conservation areas. Many of these
conservation areas are in remote locations
such as islands, and monitoring pest animals is
labour intensive. Determining ‘pest free status’
means physical monitoring of large areas for
long periods of time, with no guarantee of
detection. Until recently the most common
way of discovering which animals were in an
area was to use tracking tunnels. Conservation
staff had the laborious task of collecting and
analysing the pieces of card with unclear
footprints and tracking card deterioration
making analysis particularly difficult. Dr
Helen Blackie and her team were determined
to combat this detection problem, and
conducted research into how this problem
was handled by other countries’ conservation
authorities. This research revealed nothing
useful. So Blackie and her team decided to
start with a blank canvas and develop their
own solution. The key premise was the need
for an automated detection device that
was rugged enough to withstand being
left in the field for long periods. A tool that
would help determine animal numbers and
population characteristics as part of long-term
conservation control programmes. In addition,
the units also had to be responsive enough
to track animals moving quickly in and out of
the tunnels, with a long battery life and few
maintenance needs. These requirements led
to the concept of a sensor pad with the ability
to store information about what animal had
stepped on it and when.
AWMS ... www.awms.org.au
The units’ development
involved a broad range
of skills from different
organisations: animal
behaviour knowledge and
evaluation from Blackie and
her team; a concept for the
Dr Helen Blackie
sensor from Dr Ian Woodhead,
chief scientist at Lincoln Agritech - including
electronics and software from their engineer
Paul Riding; and mechanical and enclosure
design, printing and fabrication by Auckland
University of Technology product design
lecturer Shane Inder. A collaboration which
may serve as a good example for future
projects. The two-and-a-half-year-old project
has run “surprisingly smoothly” and the result
is an innovative device, nicknamed the ‘nose
cone’ because of its shape and removable
hood. It can be placed either in existing
tracking tunnels or in other locations and uses
clever electronic technology to identify and
classify species.
It’s currently being tested on the West Coast
of New Zealand where it has been sited
alongside motion sensing cameras to doublecheck its accuracy. The current trials show
95% accuracy for stoats, ferrets, possums, cats,
rats and mice. The device has already attracted
international interest due to its potential to
identify pests on cargo ships or in grain silos,
as well as conservation agencies wanting to
remotely monitor populations of threatened
animals.
The device will help with crucial management
decisions such as, when to stop control
programmes and is also a breakthrough
in reducing the expenses of long-term
monitoring. The commercial applications are
huge and further development could see
the technology designed to work alongside
systems such as a vaccine delivery device for
control of animal diseases.
Australasian Wildlife Management Newsletter
2
Presidential Mutters
Peter Fleming
Committee matters
Your Committee has been busy over the past few months.
Terry Korn and Don Fletcher have been investigating how
AWMS can be recipient of donations to enable members
to take advantage of our reciprocal arrangements with
the Southern African Wildlife Management Association
(SAWMA) and The Wildlife Society (TWS). Although we
already have some generous awards and travel grants,
further student prizes and subsidised study trips to and
from southern Africa and North America would cement
and benefit relationships between members and the
organisations.
Enabling AWMS to receive tax deductable donations
requires registration with the Australian Tax Office as
a Deductible Gift Recipient. This in turn requires some
amendment to our Constitution. Terry Korn is drafting a
clause for addition to the Constitution, and the proposed
amendment will be put to the 2013 Annual General
Meeting in Palmerston North. I urge members to consider
the suggested changes and look forward to discussion at
the AGM. Watch the listserver emails for developments
AWMS Website
Tarnya Cox has done a great job in upgrading our website
and I encourage you to have a look at the activities that
can be undertaken. The photos streaming across the top of
the website are all by our members, many being winning
entries at Conference Photo Competitions. So get onto the
website, get connected with other members, set up a forum
(work out who you can share accommodation and travel
expenses with at the Conference), post an avatar (it would
appear that Eamon O’Meara is a small, stripy marsupial) and
upload some photos for interest and bragging.
While you’re on the AWMS website members’ pages, have
a look at Don Fletcher’s photo album to see some of the
things his ACT group gets up to. I’ve added a few photos
including some from my 2010 travels in Kruger National
Park as guest of Brian Reilly and SAWMA. Andrea Byrom and
I have both uploaded pictures of members at conferences.
Check yourself out; those Hawaiian shirts at the Fremantle
conference struck a chord (or perhaps a nerve) and feature
prominently.
CSIRO Publications
AWMS has entered into two sponsorship and publication
agreements with CSIRO Publishing. Those members
who attended the First International Camera Trapping
Colloquium last year will be pleased that the Proceedings
book of papers and camera trap photographs will soon be
published.
AWMS and the Royal Zoological Society of NSW provided
sponsorship to reduce the price of the publication and both
Societies will receive ongoing royalty payments on sales of
the book. These will assist in funding our awards, prizes and
other activities.
Our publication contract stipulates that the contents will be
with CSIRO Publishing by November and that the book will
be published within 6 months of receipt. Paul Meek and the
editorial committee have been working hard to have all the
papers peer-reviewed and edited for publication. Everyone
who attended the Colloquium and paid for the proceedings
in their registration will receive a copy. For other AWMS
members interested in a copy, there is a special deal as
part of the contract that AWMS can provide members with
copies at 40% discount on recommended retail price (to be
announced), plus postage and handling. Congratulations to
Paul Meek on his sterling felid-wrangling efforts in driving
the process from conception to publication.
Alistair Glen and Chris Dickman have recently edited a book
on Carnivores in Australia: Past, Present and Future, and
sought sponsorship from the AWMS Committee. Many of
the authors of the various chapters are AWMS members
and the committee met out of session (without Al, who
is one of your Committee members) to discuss possible
sponsorship. I approached CSIRO Publishing about how the
Society could provide sponsorship to reduce the cost of the
publication so that it was more within the price range of
members, particularly students.
I’m pleased to announce that with AWMS sponsorship,
the recommended retail price of the 18 chapter book will
be below $100, which should encourage sales in Australia
and overseas. There are a number of other benefits for
AWMS members: members will be offered a 25% prepublication discount, the society will be acknowledged on
the copyright page and our logo will adorn the back cover.
In addition, Al and Chris have generously forgone their
royalties and these will be paid to AWMS.
AWMS Awards
As the Society is currently well placed financially, the
Committee has taken the opportunity to provide a one-off
payment of $10,000 to the Australian Academy of Sciences
to allow the Caughley Travelling Fellowship to be more
generous and appealing to AWMS members and others.
The Fellowship now is for $7000 and can be accessed
through the Australian Academy of Science website http://
www.science.org.au/awards/travelling-fellowships.html
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
3
Presidential Mutters
Continued from page 2
We have had strong fields entered for our three annual
awards, the DW Cooper Student Thesis Award, the
Practitioners Award and the Honours and Undergraduate
Travel Scholarship. The winners of the first two awards will
be announced at the Conference Dinner.
I can announce that ANU student Cheng Tan receives the
Travel Scholarship. Cheng will use his award to undertake a
study on tree gecko (Gehyra variegata) thermal ecology at
Fowlers Gap (probably not the most exotic of destinations,
but the geckos seem to prefer it out there). As he said in his
application he “hopes to gain insights on thermoregulation
in lizards in general and how they would respond in a
changing environment. If major patterns of habitat use by
the tree gecko are determined by thermal regimes, we may
be able to predict other threatened species movement in
response to habitat alteration or global warming and hence
devise more effective conservation measures.” Fowlers
Gap has been the site of many ecological studies that have
informed wildlife management and I’m sure Cheng’s study
will add to that auspicious list.
AGM and Committee Member Nominations
At the Annual General Meeting, which will be held at
Massey University at 17:15 on 21st November 2013, the
Committee positions of President, Vice-President, Treasurer,
Membership Secretary and Committee Member #2, and the
Student Representative position will all fall vacant. My role
as President has been made most enjoyable by this great
group of people working for the benefits of the Society and
its members. I thank them sincerely.
All AWMS members are invited to nominate (or second)
candidates for the vacant positions. This is your chance to
volunteer for a role in the group that keeps your Society
running. If you want a greater say in the direction of the
Society, please nominate. If you have a colleague that you
think would be great in one of these positions, encourage
them to have a go and nominate them.
Nominations of candidates for Committee members are
to be in writing, signed by two members of the Society,
accompanied by the written consent of the candidate, and
delivered to the Secretary (Lyn Nelson) by cob Thursday 14th
November 2013.
My particular thanks to Greg Baxter, our Vice-President, and
Don Fletcher, our long-serving Treasurer, who have provided
such valuable service to the Society over the years. Greg
and Don will step down at the AGM and do not intend to renominate. Greg has provided great support to me over the
last two years and Don has ensured that our accounts are in
good shape, allowing us to improve member services.
The role of Treasurer has been difficult as we have
transitioned to new systems, but now that the new systems
are mostly in place, the role will be less taxing for the
incoming Treasurer. I also thank Terry Korn for all his advice
and assistance as immediate past president - it will be
difficult for me to emulate his level of involvement.
Parting thoughts
The success of the Camera Trapping Colloquium was due
not in small part to the dual sponsorship from AWMS and
RZS and the associated generous support of Taronga Zoo
that this facilitated. The number of Colloquium delegates
exceeded our financial membership at the time, and I
hope that some of our recently joined new members
were prompted to join by witnessing one of the great
opportunities the Society provides.
This collaboratively run program and being a member of a
number of small societies, as I know many of you also are,
have given me insights into how AWMS can continue to
grow and prosper. One group that I have been a member
of since 1986 is undergoing a downturn in membership
as research investment is withdrawn and older members
retire. I’m pleased to say that, due to the activities of your
Committee and involvement of the membership, AWMS is
strong and growing. However, if we are to remain relevant,
we must continue to maintain and improve the services
the Society offers its members, while realising that this
depends on the hard work of committed volunteers, and
active involvement of members. Our strength is also our
vulnerability.
In the middle of the year, the UNE/ NSW DPI wild canid
research group at Armidale was well represented at the
Australian Mammal Society conference. Our students and
and staff benefitted from presenting at a different forum and
from the broadening of their networks. I noticed that there
was a strong contingent of AMS members who have officially
retired but remain involved, providing mentoring (and high
quality limericks) which benefit younger members. I hope
that retirees will feel welcome to continue their membership
with AWMS as they are highly valued and valuable.
Recently, I attended the 22nd International Grassland
Congress, where Desley Whisson and I, with Chinese
colleague Hua Limin, presented about the management of
burrowing invasive mammals. The theme of the congress
was Revitalising Grasslands to Sustain our Communities; all
these key words pertain to wildlife management.
Most of the Congress presentations were about herbage,
forage and livestock production but there were a few other
wildlife management presentations, including an interesting
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
Presidential Mutters
Continued from page 3
pilot investigation on the effects of different livestock
co-grazing on birds and mammals in Uruguay. This study,
with great potential to provide evidence to benefit comanagement of livestock and wildlife, would have benefited
from the experimental design elements that are a strength
of our Society. A collaboration waiting to happen?
At first it would appear that there was little in common
between grasslands societies and AWMS but both wildlife
and livestock management would benefit from collaboration
between our groups. This must occur if we are to feed and
clothe the world, which is approaching 9 billion mostly
wildlife-unaware people, while maintaining and improving
the lot of the wildlife we all value so greatly. I do not see our
organisations as competitors, but complementary. There
is niche overlap but enough niche separation to enable
organisations with different foci to co-exist.
I encourage members to join sibling societies, such as AMS
and RZS, as well as AWMS, thereby ensuring not only survival
and expansion of the societies, but enabling synergies
and connections with AWMS that might not otherwise be
evident. As wildlife management scientists and practitioners,
we already require familiarity with a wide range of
disciplines from wildlife biology, ethology and ecology,
through biometry and the dismal science, economics, to
human dimensions, human behaviour and cognitive science.
Promulgating the vision of the Society requires us to share
our knowledge with other organisations, so that they are
aware that wildlife management has a developing evidence
base on which to make decisions and so that we are aware
of different world views that will affect appreciation and
application of scientific management of Australasian wildlife.
Conference Travel Subsidy
AWMS encourages and supports student
participation at the annual conference. To
enable students to present at the annual AWMS
conference, the Committee provides a travel
subsidy for AWMS student members. To be
eligible for a travel subsidy, students must have
approval of their supervisor and present a talk at
the annual conference.
Click here to read more ....
4
Australasian Wildlife Management Society
Annual General Meeting 2013
All AWMS members are advised that the AGM will be
held at 5:15 pm (NZ summer time) on Thursday 21
November 2013 at Massey University, Palmerston
North, New Zealand. The AGM will be held in one of the
meeting rooms used for the 26th AWMS Conference.
Items to be covered:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Minutes of 2012 AGM (see AWMS website for copy)
President’s Report
Correspondence (Secretary)
Treasurer’s Report
Membership Secretary’s Report
Position Statement Co-ordinator’s Report
General Business
- Student Representative’s Report
Other Business
- Amendments to Constitution
Election of Committee Members
Have you
registered
for the AWMS
Conference
yet?
Do it now
CLICK HERE
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
5
The impact of invasive cane toads on native animal communities: Project Kimberley
Theme: Wildlife Management and Water – How muddied are the waters by a boom and bust system?
J. Sean Doody, University of Tennessee, [email protected], Colin McHenry, Monash University, [email protected],
Simon Clulow, University of Newcastle, [email protected]
Most readers will know the Australian cane toad story. They
were released in Queensland in 1935 to control sugar cane
pests, but ironically became a bigger pest themselves; as
they marched across northern Australia they left a wake
of dead animals in their path. But as toads moved across
Queensland we had little idea of the seriousness of their
impacts within species. We knew that would-be predators
essentially suffered a heart attack while attempting to ingest
the toxic toads, but did these dead animals reflect serious
population-level impacts? Clearly, whether a species suffers
1%, 10%, or 90% declines has important ramifications for
species persistence, ecosystem function, and governments
investing resources into controlling toads.
As cane toads moved through the Northern Territory the first
studies quantifying impacts revealed some sobering results.
Before-and-after studies on the Daly River spanning seven
years revealed 71-97 % declines in three species of monitor
lizards (Varanus panoptes, V. mertensi, V. mitchelli; Doody
et al., 2009). Although toad-killed individual freshwater
crocodiles did not reflect population-level declines on
the Daly, declines in crocodiles averaged around 45% in
the upper Victoria River (Letnic et al., 2008). Meanwhile,
radiotelemetry revealed snapshot population crashes in
the northern quoll (Dasyurus hallicatus) and the yellowspotted monitor, (Varanus panoptes; Oakwood, 2004; Ujvari
and Madsen, 2009). Moreover, other species may have
suffered major impacts in some populations (e.g., northern
bluetongue skinks, Tiliqua scincoides; northern death
adders, Acanthophis praelongus). A basic understanding of
which species were impacted began to emerge, although
a diversity in responses among freshwater crocodile
populations complicated the pattern and indicated that
more monitoring was required to arrive at any consensus of
direct impacts of cane toads on native predators.
What about indirect impacts of cane toads? In a land
depauperate of large mammals, reptiles often fill the role of
top predators in Northern Australia, and the yellow-spotted
monitor is a good example. When toads essentially remove
this large lizard (up to 7 kg) from the animal community,
we would predict cascading effects on the monitor’s
prey. This is exactly what has occurred in the Northern
Territory, with increases in four species of common prey
of the yellow-spotted monitor after toad arrival. Gilberts’
dragons (Amphibolorus gilberti) and common tree snakes
(Dendrelaphis punctulatus) increased by 4-28 fold along the
Daly River following toad arrival (Doody et al., 2009; 2012).
Recruitment increased by 4-5 fold in both the pig-nosed
turtle (Carettochelys insculpta) and the freshwater crocodile
coincident with the toad-induced declines in V. panoptes
(Doody et al., 2006; Webb and Manolis, 2010).
A few other snake species may have also benefitted from the
decrease in V. panoptes (Brown et al., 2011), and recruitment
in the crimson finch (Neochmia phaeton) increased from
55% to 81% coincident with toad-induced declines in
two of the finch’s major nest predators, V. mitchelli and V.
mertensi (Soanes, 2011; Doody, unpubl. data). Thus, the
so-called ‘trophic downgrading’ caused by cane toads, is
having cascading effects across trophic levels in the tropical
savannah ecosystem.
Cane toads are now firmly established in the east
Kimberley region. Prior to this invasion, ‘Project Kimberley’
was established in 2009. Project Kimberley is a research
consortium that includes Monash University, University
of Tennessee, University of Newcastle, Stop the Toad
Foundation, Australian Geographic Society, Frogwatch,
and El Questro Wilderness Park. The initial goals of Project
Kimberley were to (1) determine the impact of cane toads
on native animal communities; (2) engage in local control
efforts to minimise toad impacts; (3) raise awareness of toad
impacts and control options; and (4) train stakeholders in
wildlife knowledge, identification and handling.
The initial field monitoring sites for the project were the Ord
River and El Questro Wilderness Park in the east Kimberley.
Toads have recently invaded these sites, and results are now
being analysed. Initial results indicate severe populationlevel impacts on the northern quoll, yellow-spotted monitor,
Mitchell’s water monitor, and Mertens’ water monitor, with at
least individual and perhaps population-level effects on six
other species of monitor lizards, and northern bluetongue
skinks. In particular, northern quolls have disappeared from
all 15 remote camera monitoring stations (Fig. 1).
On the positive side, freshwater crocodiles seem to have
suffered modest population-level impacts at El Questro,
but negligible impacts at the Ord River, and the sandstone
longneck turtle (Chelodina burrungandjii) appears to have
suffered only individual impacts. Further monitoring over
the next two years will determine any cascading effects of
the losses of top predators.
Although broad scale control of cane toads appears to
be untenable, Project Kimberley embraced an attempt at
local control at Emma Gorge in El Questro. Emma Gorge is
a tourist attraction in the Cockburn Ranges at El Questro
that contains rainforest elements, permanent water, and a
remarkable diversity of animals including nine species of
monitor lizards. A 2 km-long cattle fence that closes off the
entrance to Emma Gorge was converted to a toad-proof
fence prior to the arrival of toads (Fig. 2).
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
6
The impact of invasive cane toads on native animal communities
Continued from page 5
The goal was to keep toad numbers very low in the gorge
using the combination of the exclusion fence, the sheer
cliffs surrounding the Cockburn escarpment in which the
gorge is dissected, and toad collection inside the gorge
of any trespassing toads. The fence has been a successful
barrier, and initial results were encouraging as toads exist
in low numbers in the gorge. However, toads have now
quickly moved to the top of the escarpment from other
gorges in the northern escarpment, and are entering the
gorge from the waterfall at the Emma Gorge terminus.
Regular collection of toads at the base of the waterfall and
elsewhere within the gorge has kept toads in relatively low
numbers, but the experiment is relying heavily on volunteer
participation of El Questro guides and staff.
A secondary goal of the Emma fence was a trapline to
sample vertebrate biodiversity before and after toad arrival.
To date the project has recorded 61 species of vertebrates
from the fence. Numerous students, guides, and volunteers
have been trained in wildlife identification and handling
at the fence, and El Questro is developing a tour along
the fence that will promote a better understanding of our
precious natural heritage in the Kimberley.
In a land rife with feral animal problems, the cane toad is
proving to be unique and more formidable than previously
thought. During the surveys cane toads were found in
virtually every habitat on El Questro, including high cliffs
under very dry conditions. Surprisingly, toads were active
in some areas during the daylight hours. They were found
in sand track stations, in mammal traps, pitfall traps, funnel
traps, and in the burrows of monitor lizards. They are not
only present in large numbers but are now the dominant
conspicuous vertebrate in the tropical savannah woodland
ecosystem.
Future plans
Project Kimberley is now moving into a second phase, while
completing the first phase over the next two years. In the
second phase Project Kimberley will be (1) determining
the impact of cane toads on genetic diversity of at-risk
vertebrates; (2) developing techniques to preserve genetic
diversity (through gene-banking and assisted reproductive
technologies); and (3)determining the impact of toads on
the social system of the yellow-spotted monitor.
The Cane Toad (Rhinella marinus) replaces the northern quoll (Dasyurus
hallicatus) at El Questro Gorge. This camera photographed at least 6
individual quolls 49 times during 27 June 2012 through 15 January 2013
(the last photograph of a quoll).
Toads invaded the gorge in January 2013, and were first photographed by
the same camera on 20 January. Quolls were not detected again by the
camera despite its continued deployment through 19 April 2013.
The first two of these aims – population genetics and genebanking –have been dubbed the ‘Kimberley Ark’. Arguably,
the biggest problem associated with rapid and severe
population decline is the loss of genetic diversity. Genebanking is the best method available to prevent the loss of
genetic diversity caused by declines in wild populations,
when the causes of decline cannot be halted or reversed.
By targeting species that are known to be at risk from toads
(using data from our work at El Questro) we are embarking
on an ambitious programme to establish a national gene
bank for the Kimberley region. We will develop assisted
reproductive technology protocols that allow long-term
storage of gametes and/or somatic tissues, working with
reproductive biologists at Monash University and the
University of Newcastle. As the news surrounding the
successful cloning of the southern gastric brooding frog
shows (which involved members of our team), this field is
developing rapidly and is not limited by our capacity to
generate viable embryos from frozen tissue – rather, the
limitation is having access to banked-down tissues.
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
7
The impact of invasive cane toads on native animal communities
Continued from page 6
The other component of the Kimberley Ark concept is
mapping the genetic structure of the populations to be
banked. If the population is not highly structured, then
animals can be sampled from any location to store original
levels of genetic diversity, so long as tissues from enough
animals are banked down. If, however, the population has
high levels of structure, the banking of tissues needs to be
carefully targeted. In either case, quality information on
the population genetics is essential for successful storage
of genetic diversity – and will teach us much about the
population ecology of these species in the process.
Literature cited
Brown, G. P., Phillips, B. L., & Shine, R. (2011). The ecological impact
of invasive cane toads on tropical snakes: field data do not
support laboratory-based predictions. Ecology, 92(2), 422-431.
Doody, J. S., Green, B., Sims, R., Rhind, D., West, P., & Steer, D. (2006).
Indirect impacts of invasive cane toads (Bufo marinus) on nest
predation in pig-nosed turtles (Carettochelys insculpta). Wildlife
Research, 33(5), 349-354.
Doody, J. S., Green, B., Rhind, D., Castellano, C. M., Sims, R., &
Robinson, T. (2009). Population‐level declines in Australian
predators caused by an invasive species. Animal Conservation,
12(1), 46-53.
Doody, J. S., Castellano, C. M., Rhind, D., & Green, B. (2013). Indirect
facilitation of a native mesopredator by an invasive species: are
cane toads re-shaping tropical riparian communities?. Biological
invasions, 15(3), 559-568.
Letnic M, Webb JK, Shine R (2008) Invasive cane toads (Bufo
marinus) cause mass mortality of freshwater crocodiles
(Crocodylus johnstoni) in tropical Australia. Biol Conserv
141:1773-1782
Letnic, M., Webb, J. K., & Shine, R. (2008). Invasive cane toads
(Bufo marinus) cause mass mortality of freshwater crocodiles
(Crocodylus johnstoni) in tropical Australia. Biological
Conservation, 141(7), 1773-1782.
Oakwood, M. (2004). The effect of cane toads on a marsupial
carnivore, the northern quoll, Dasyurus hallucatus. Report to
Parks Australia, Darwin
Ujvari, B., & Madsen, T. (2009). Increased mortality of naïve varanid
lizards after the invasion of non-native cane toads (Bufo
marinus). Herpetological Conservation and Biology, 4(2), 248-251.
Webb, G. J. W. & Manolis, S. C. (2010). Australian Freshwater
Crocodile Crocodylus johnstoni. In: Manolis, S. C. & Stevenson,
C. (eds) Crocodiles. Status survey and conservation action plan.
Crocodile Specialist Group, Darwin, pp 66-70.
Study area, showing the 1.7 km-long cane toad
exclusion fence across the entrance to Emma
Gorge, in the Cockburn Ranges, El Questro
Wilderness Park, north Western Australia. Colours
link points along the trapline with the elevation
profile.
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
8
When aliens replace natives: impacts of black rats (Rattus rattus) in the
Sydney Harbour National Park
Helen M. Smith, The University of Sydney, [email protected]
The invasion of non-native species
into foreign ecosystems is one of the
biggest challenges for conservation
biologists. The black rat (Rattus
rattus) is one of the most successful
colonisers worldwide and has been
linked to a high number of native
species declines, particularly on
islands where natives are naive to
rodent predators (Atkinson, 1996).
In the Sydney Harbour National Park
the invasive black rat has replaced
the native bush rat (Rattus fuscipes)
(Banks et al. 2011), and now threatens
the conservation status of endemic
Australian wildlife. In 2011, native bush
rats were reintroduced into Sydney
Harbour to test if bush rats could
block the reinvasion of black rats by
interference competition. I was part
of a research team lead by Associate
Professor Peter Banks at the University
of Sydney, and we worked with other
sponsors including the Australian
Wildlife Conservancy, local councils,
national parks and Taronga Zoo to
translocate the bush rats. We predicted
that bush rats would competitively
exclude reinvading black rats at a local
scale (based on past research in Jervis
Bay by Stokes et al. 2009), and that
the benefits to local fauna and flora
could be detected. At present, the
degree of ecological damage induced
by black rats is not well described in
Australia (see Banks and Hughes 2012),
and so my PhD research focused on
firstly determining whether the bush
rat reintroduction in fact worked,
and secondly, whether it provided
ecological benefits to native wildlife in
Sydney Harbour National Park.
One hundred bush rats were released
amongst four sites in Sydney Harbour
National Park in August 2011. All sites
were monitored periodically for a year
after the release and breeding was
observed on all sites.
Importantly, we found fewer black
rat invaders on bush rat sites
suggesting that bush rats were able
to block black rats from moving
into regions where bush rats were
resident. Following the successful
reintroduction, I then monitored the
sites to establish if reintroduced bush
rats could also reduce the ecological
impacts of invasive black rats. Firstly
I used a spool and line technique to
monitor how bush rats and black
rats moved through the bushland. I
found that black rats climbed three
times as much as bush rats, and
hence occupied an empty arboreal
predator niche. This suggests that
when black rats are present in many
areas of Australian bushland, they
could threaten many vertebrate
and invertebrate communities that
otherwise lack predation from arboreal
rodents. Following this result I used
a series of experiments to examine
the impact of black rats and bush rats
on local arboreal fauna: here, I report
specifically on the impacts of black rats
on bird egg survival and invertebrate
abundance to investigate exactly how
the predation impacts of invasive rats
differ to native bush rats. Essentially
my work explored the concept of
reversing the consequences of black
rat invasion through a native bush rat
reintroduction program.
Egg survivorship was measured by
using artificial nests that simulated
New Holland honeyeater nesting
habits. I found that egg survivorship
was significantly lower on sites with
high black rat densities suggesting
that black rats pose a considerable
predation risk to small birds. More
importantly, egg survivorship on sites
where black rats were continually
removed was equivalent to egg
survival on bush rat reintroduction
sites.
This result suggests that continual
removal of black rats can be replaced
by the more ecologically sustainable
technique of reintroducing bush rats.
Invertebrate responses showed a
similar pattern. I sampled the arboreal
invertebrate community on all sites
using artificial bark. I found that
invertebrates were highest on grids
with low black rat density with large
spiders being most susceptible, again
indicating that black rats pose a major
threat. Again, this result suggests that
black rats pose a major threat to local
invertebrates, Sand that these impacts
can be reduced by replacing alien black
rats with reintroduced bush rats. This
work paves the way for other studies
to use similar restoration techniques
to block population recovery of alien
species after control. It is a particularly
advantageous strategy because it not
only delivers lower pest numbers but
also reduces the ecological impacts of
the pest species.
Future aspirations
I would definitely like to continue
working in conservation research
and specifically in bridging the gap
between theory and application of
ecologically based management
strategies. I am a passionate
bushwalker and canyoner and my ideal
job would see me spending a lot of
my time out in the field. At some point
I’d love to work in the remote canyon
regions in the northern parts of the
Wollomi National Park north of Sydney,
but before that I’d like to get a bit more
research experience and I’m open to
exploring options in other countries!
Continued on page 9
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
9
When aliens replace natives: impacts of black rats (Rattus rattus) in the
Sydney Harbour National Park Continued from page 8
Literature cited
Atkinson, I. A. (1996). Introductions of
wildlife as a cause of species extinctions.
Wildlife Biology, 2(3), 135-141.
Banks, P. B., Cleary, G. P., & Dickman, C.
R. (2011). Sydney’s bubonic plague
outbreak 1900-1910: a disaster for
foreshore wildlife?. Australian Zoologist,
35(4), 1033-1039.
Stokes, V. L., Banks, P. B., Pech, R. P., & Spratt,
D. M. (2009). Competition in an invaded
rodent community reveals black rats
as a threat to native bush rats in littoral
rainforest of south‐eastern Australia.
Journal of Applied Ecology, 46(6), 12391247.
Banks, P. B., & Hughes, N. K. (2012). A
review of the evidence for potential
impacts of black rats (Rattus rattus) on
wildlife and humans in Australia. Wildlife
Research, 39(1), 78-88.
Bush rat – Sydney Harbour National Park
(Photo- Helen Smith)
Artificial birds’ nest with plasticine and quail
eggs– Sydney Harbour National Park (PhotoHelen Smith)
AWMS Committee positions
for nomination and election at 2013 AGM
Most of the AWMS Committee’s elected positions will become vacant
immediately following the Annual General Meeting on 21st November 2013.
All AWMS members are invited to nominate (or second) candidates for the
following positions:
•
•
•
•
•
•
President
Vice-President
Treasurer
Student Representative
Membership Secretary and
Committee Member #2.
This is your chance to volunteer for a role in the group that keeps your Society
running.
Helen Smith with a black rat – Sydney Harbour
National Park (Photo- Peter Harvey)
Nominations of candidates for Committee members are to be in writing,
signed by two members of the Society, accompanied by the written consent
of the candidate, and delivered to the Secretary (Lyn Nelson) by cob Thursday
14th November 2013.
Seconded nominations, together with the written consent of the candidate,
can be scanned and e-mail to [email protected] or posted to:
Dr Lyn Nelson
Secretary
Australasian Wildlife Management Society
PO Box 187
VINCENTIA NSW 2540
Australia
to arrive by 5:00 pm Australian Eastern Summer Time 14th November 2013.
If you have a colleague that you think would be great in one of these
positions, encourage them to have a go and nominate them.
Black rat – Sydney Harbour National Park
(Photo- Mal Weerakoon)
The current President, Vice-President and Treasurer do not plan to renominate so we are particularly keen to receive nominations for these
positions.
Volume 27, Issue 3
Australasian Wildlife Management Newsletter
10
Wild Supply offers a range of tracking and monitoring
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Our goal at Wild Supply is to offer innovative and cost effective systems for
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Volume 27, Issue 3
Australasian Wildlife Management Newsletter
11
AWMS 2013
Australasian Wildlife Management Society Annual Conference
see you there
20-22 November 2013
Massey University
Palmerston North, New Zealand
THEME: Advances in Reintroduction of Australasian Fauna 1993-2013
Convenor: Doug Armstrong - [email protected]
www.awms.org.au - REGISTER HERE
After attending the AWMS Conference, members may wish to move onto the EcoTas Conference ......
EcoTas13, the 5th joint conference of the New Zealand Ecological Society and the Ecological Society of
Australia will be held in Auckland, New Zealand from the 24th to 29th November, 2013.
Celebrating ecology on both sides of the Tasman: diversity and opportunity
We invite you to attend the latest of a series of conferences held between the Ecological Society of Australia and the New
Zealand Ecological Society to celebrate advances in ecological science, and the ecological connections and differences
between the two countries. The conference will create a critical forum on ecology for researchers, managers and policy
makers, and we urge ecologists covering the full range of ecosystems, life forms, approaches, and scales to attend and
highlight their valuable contributions.
Contact: Bruce Burns, Chair Local Organising Committee
Email [email protected] or [email protected]
For more information, visit the meeting website @ www.ecotas13.org
Volume 27, Issue 3