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Thursday, 1 November 2012
Page: 8901

Sustainability, Environment, Water, Population and Communities

(Question No. 2131)

Senator Siewert asked the Minister representing the Minister for Sustainability, Environment, Water, Population and Communities, upon notice, on 31 August 2012:

Given that: (a) in 2010, a team of scientists led by noted biologist Dr John Woinarski reported a 71 per cent decline in small mammal numbers in Kakadu National Park for the period between 1996 and 2007, in addition to recording declines among other animal groups; (b) possible causes have been discussed by Dr Woinarski in the peer reviewed scientific journal Wildlife Research, including the spread of cane toads across Northern Australia, unsuitable fire regimes and feral cats; and (c) Dr Woinarski and his team have called for an urgent management response in Kakadu National Park, notably adaptive management trials and targeted research on the population dynamics of the rare and unique fauna:

(1) Is the Minister aware of this paper.

(2) Can an outline be provided of the department's response to this crisis.

(3) Apart from ongoing monitoring, what action is being taken to determine the possible causes of this wildlife decline.

(4) Are fire proof exclosures, free of cats and toads, being set up.

(5) Is the department establishing 'extinction-proof' captive colonies of endemic and threatened species inside and/or outside the Kakadu National Park.

(6) What action is being taken by qualified biologists to identify the status of the endemic and threatened animals of Kakadu National Park before they actually become extinct.

Senator Conroy: The Minister for Sustainability, Environment, Water, Population and Communities has provided the following answer to the honourable senator's question:

(1) The Minister is aware of Dr Woinarski's report and the worrying issue of small mammal decline in Kakadu National Park and across Northern Australia, including Queensland, Western Australia and the Northern Territory.

Potential causes for the decline include disease, predation and over-grazing by feral animals, and inappropriate fire regimes or, as is most likely, a combination of all these factors.

(2) In accordance with the Kakadu Management Plan, park staff continually review and adapt key management tools such as the fire, feral animal and weed control strategies to ensure they reflect the most up to date research and accord with best practice in conservation management.

Traditional owners and park staff work closely with the park's Research Advisory Committee to ensure its research agenda responds to priority management issues such as small mammal decline. The advisory committee consists of 15 scientists, experts in a number of disciplines, drawn from a variety of institutions both academic and government. Kakadu park staff also work closely with Dr Woinarski who provides important services to the park and collaborates with park staff on periodic fauna surveys of Kakadu.

As prescribed in the Management Plan, Kakadu traditional owners and park staff collaborate with researchers from a number of institutions and organisations - in particular with researchers from the Northern Territory Government and Charles Darwin University- to better understand what is happening and protect the park's biodiversity.

In partnership with the North Australia Hub of the National Environmental Research Program (NERP), the park is collaborating on a number of significant research projects in Kakadu, including on small mammal decline and climate change.

One of these projects is focusing on the potential role of feral cats as a cause of small mammal decline.

During 2010/2011, biodiversity surveys located a number of individual quolls and another small population of quolls persisting despite the presence of cane toads.

Results from these surveys have been used to prioritise potential sites for the cat exclosures proposed under the NERP project.

The next biodiversity 'hotspot' survey is scheduled for the 2012/2013 wet season and will target Oenpelli pythons and Kakadu's giant skink.

Kakadu's approach to fire management is based on a mix of traditional Indigenous burning practices and modern science and has been applauded by fire experts in Australia, and has been adopted as a model elsewhere. There continues to be room for improvement in the use of fire in the park, in response to input from traditional owners and researchers working in the park.

The Stone Country Fire Management strategy targets an area of the Arnhem Land Plateau that is a biodiversity 'hotspot' with a high number of endemic species. The strategy allows for fine scale fire management, paying particular attention to threatened species and communities such as the sandstone heath community. Park staff walk the stone country with traditional owners, working together on fire management. Implementation of the first five years of this strategy is currently under review.

Kakadu's strong relationships with its neighbours, particularly the Indigenous communities to the east, has led to the development of cross-tenure approaches to land management. For example the park works closely with an adjoining Indigenous Protected Area (IPA) to collaboratively manage fire on the Arnhem Land Plateau.

(3) Following Dr Woinarski's suggestion of a possible disease-related cause for the decline, a study was carried out to investigate this hypothesis but did not reveal any blood-borne diseases or significant parasitic infections as causal factors in the decline.

Kakadu's biodiversity 'hotspot' survey program targets threatened species habitats, including those of small mammals. This research has identified several sites with higher numbers of small mammal species than previously noted, although they are still not at the population levels recorded prior to the decline.

The park maintains one of the longest running fire plot research and monitoring studies in the country and seeks opportunities to refine aspects of this research. Recently Kakadu successfully partnered with the University of Tasmania to secure Australian Research Council (ARC) funding to assess the impact of the grass-fire cycle on biodiversity in Kakadu's stone country.

The Minister recently agreed National Environmental Research Program (NERP) funding for the Northern Australia Hub Terrestrial Biodiversity Conservation project. This includes an initiative to better understand the impact of feral cats on small mammal decline.

Currently research is focussing on how best to monitor cat numbers using remote cameras.

Based on preliminary trapping and remote cameras, several potential sites for cat exclosures have been selected.

Once this project is completed the exclosures could potentially be used to reintroduce threatened species to the park in an area free from feral predation.

Kakadu is collaborating with Sydney University and the Northern Territory Government on a 'toad-averse' quoll release program. Captive-bred quolls are fed a small dead toad laced with a nausea-inducing chemical. The quoll then associates the smell and taste of cane toads with feeling sick.

Early indications are promising with released animals persisting and breeding in the wild and apparently passing on their toad aversion to their young.

So far 70 quolls have been released and 50 individuals have been trapped. Of these:

12 were from a population persisting in the wild

20 were toad averse trained individuals

17 were juveniles.

The origin of other individuals is unknown

DNA testing has shown that about half the juveniles are offspring of toad-averse trained females. One recently trapped quoll was the grand-daughter of a trained quoll that had been released. This is very encouraging as it suggests that toad-averse trained females are passing this information to their young.

(4) Fire is an essential part of Kakadu's and northern Australia's ecology. Exclosures are being established to measure the impact of cats on small mammals but these do not exclude fire or toads. This decision was taken by the researchers who designed the research project.

(5) No captive colonies of endangered species have been established in Kakadu. However the park has played a key role in the Northern Territory Government's Island Ark project, under which threatened northern quolls have been translocated to toad-free offshore islands. The relocated quoll populations are doing very well and breeding successfully.

Once the cat exclosure project is underway, there is potential to consider the re-introduction of threatened species.

(6) The biodiversity 'hotspot' surveys, full fauna and flora surveys and 136 fire plots continue to provide important information on the status of Kakadu's biodiversity. Kakadu's fire plot survey program provided the information that initially identified the small mammal decline in the Top End.

In addition to the research and management approaches mentioned above, the park coordinates an incidental fauna sighting program which is a valuable addition to the existing structured research programs. Some of the more interesting recent sightings include:

Oenpelli pythons

Yellow chats

Conilurus (rabbit eared rat).

Rufous owl

Black footed tree rats

Mangrove monitors


A threatened species workshop is scheduled for early 2013 in Kakadu. The workshop will bring together researchers, park staff and traditional owners to look at the current status of threatened species management and to develop guidelines for inclusion in the next Management Plan.

Representatives from neighbouring IPAs will be invited to participate the workshop will which also help develop a threatened species management strategy, to guide future investment in research and management.

The current research funded through NERP has already started to yield important results. In particular, so many glyphis sharks were found in the South Alligator River that the number of scientific records for the country has now doubled. The research shows Kakadu is a really important area for these speartooth sharks, which is declared critically endangered in Australia and vulnerable in the NT.