Restoring

Restoring

Woodland Recovery

Grass regeneration on the left when kangaroos excluded. Photo: Adrian Manning

Grass regeneration on the left when kangaroos excluded. Photo: Adrian Manning

Since 2004 the ACT Government and the Australian National University (ANU) have collaborated on a major research project entitled ‘The Mulligans Flat-Goorooyarroo Woodland Experiment’ (LINK) designed to develop a sound knowledge base for understanding and managing temperate woodlands for improved biodiversity conservation.

The research is being undertaken in both Mulligans Flat and Goorooyarroo Nature Reserves by researchers from the Fenner School for Environment and Society, the ACT Government, ANU, CSIRO and the James Hutton Institute (Scotland). The research is supported by Linkage Grants from the Australian Research Council.

This project is breaking new ground by investigating management manipulations that improve woodlands for biodiversity. Experimental management includes 1) adding dead wood, which provides habitat for animals, 2) controlling of exotic predators, which are a major threat to woodland fauna, 3) excluding kangaroos – which are having a major impact on plant biomass and 4) the use of controlled burning to manage vegetation.

The Mulligans Flat Woodland Sanctuary forms a major element of the experimental research project allowing for assessment of the ecological impact of excluding exotic pests such as feral cats, foxes and rabbits and the effects of reintroducing locally extinct species that have been lost from the system. This will provide opportunities to investigate unique research questions of direct relevance to conservation management in the ACT and the region.

The reintroduction of animals such as bettongs and bandicoots is regarded as a cornerstone of the ecological restoration project. This is because such species have been described as important ‘keystone species’ or ‘ecosystem engineers’. This refers to their roles in soil aeration and hydrology, dispersal of mycorrhizal fungal spores, incorporation of organic matter and provision of seed germination sites, among other things.

The experimental framework established for this study provides a focus for other scientific collaborations, including with CSIRO Ecosystem Science and visiting international researchers. The project also provides a focus for student research at ANU and other institutions, with several PhDs and honours projects completed, underway or planned.

Sanctuary Fence

The sanctuary fence in morning fog.

The sanctuary fence in morning fog.

The Sanctuary fence encloses approximately 485 hectares of Mulligans Flat Nature Reserve and has a perimeter of 11.5 km. The fence design is largely based on the cat, fox and rabbit-proof fence surrounding the Arid Recovery Reserve near Roxby Downs, South Australia (Moseby and Read, 2005) with specific design adaptations to cater for the grassy-woodland habitat developed by ACT Parks and Conservation Service, local experience in ACT reserves, and consultation with fencing contractors.

Nineteen gates are located on the main management tracks along the entire length of the fence to facilitate public access in the Sanctuary and to allow for routine and emergency vehicle access. Each gate has a self-closing mechanism designed to maintain the integrity of the barrier to predators, and remote sensing of the gates alerts ranger staff to any malfunction to gate closures.

The fence is 1.8m high, with 7 plain wires supporting rabbit-proof mesh (30 mm), two electric wires, a 60cm ‘floppy overhang’, and with trenched/buried netting for a width of 45cm on either side of the centre of the fence.

Some specially designed internal fences have been erected as part of the experimental research program. These fences are designed to exclude kangaroos or bettongs from several groups of experimental sites.

Feral Animal Management

Control and/or elimination of feral animal pests and over-abundant species was one of the main initial management actions in the Sanctuary. As part of its preparation for managing the Sanctuary, the ACT Parks and Conservation Service, in conjunction with the Invasive Animals CRC, established a working group which prepared a Pest Management Strategy. It has been used in the program to guide the removal of feral pests from the Sanctuary.

The aim of the strategy is to:

Minimise and where possible eradicate the fox, feral cat and wild dog and their predation impacts on native wildlife and impacts of feral and over abundant herbivores in conserving the natural habitat within the Mulligans Flat Woodland Sanctuary.

Feral Predators – Foxes and Cats

Control programs consisting of baiting and shooting these pests have been carried out since the Sanctuary was ‘closed’. It is now free of these pest species.

Feral Herbivores – Rabbits and Hares

Intensive efforts were made to remove all rabbits and hares as soon as possible after the fence was closed. This was due to their capacity to increase rapidly in numbers in the absence of predators and is essential before some mammal species could be re-introduced.

Broad scale measures to control rabbits included ripping of warrens, poisoning and shooting. As part of the initial establishment phase of the Sanctuary, warren ripping and poisoning were carried out, followed by monitoring for evidence of the continued presence of rabbits. Evidence of rabbits can be observed from their faecal droppings, active entrances into warrens, soil disturbance near warrens and, by carrying out spotlight surveys. The remaining rabbits and any hares present are removed whenever the opportunity occurs.

These measures were supplemented by the use of specially trained detection dogs, which have been successfully used to ‘flush’ out rabbits in locations such as Macquarie Island. The dogs were used in December 2011 and April 2012 to detect rabbit warrens that were then destroyed.

On-going monitoring of the Sanctuary is essential to ensure any warrens, rabbits or hares that are missed during the initial control programs are found and destroyed.

Monitoring for feral animals

Monitoring strategies used for foxes, dogs and cats include sand pads for tracks, scats and spotlight surveys. If and/or when it is known that predators have gained new entry to the Sanctuary, immediate measures to eliminate them are taken and maintained until they are no longer present.

To date there has been no evidence of incursion of new feral animals into the Sanctuary.

Regular searching for rabbit warrens and other signs of rabbits and hares is carried out in the Sanctuary. This is supplemented by night-time spotlight surveys. When necessary the Sanctuary is closed to visitors to enable appropriate control measures to be carried out.

Domestic Dogs and Cats

Mulligans Flat Nature Reserve and the adjoining Goorooyarroo Nature Reserve are designated by the ACT Government as being places where the entry of domestic pets is prohibited because of the ecological and conservation significance of the reserves. Information about this can be found on the ACT Government’s web site.

The suburbs adjacent to Mulligans Flat Nature Reserve (Forde and Bonner) are declared
cat controlled areas whereresidents are required to keep any pet cat confined to their land 24 hours a day.

However, at times these conditions may be breached either deliberately, inadvertently, or if a dog or cat has been allowed to roam free. A continuing effort to educate visitors is important, especially when small native mammals re-introduced into the Sanctuary as part of its programs. The mere presence of a dog – even if restrained – can be enough to cause injury and death to animals fleeing into the fence.

Managing the risk of pets gaining access to the Sanctuary is focused on:

Dogs or cats gaining access into the Sanctuary: Notices informing visitors of their responsibilities in relation to dogs and cats at Mulligans Flat Nature Reserve and the Sanctuary, are provided on entry gates and public information stations. The notices also include information about any operational programs that are taking place in the Sanctuary.

Dogs taking baits intended for feral predators: Local veterinarians are advised of any toxin used to control predators so that they can consider what precautionary steps they might take in the event of a pet accessing the Sanctuary and taking a bait. The toxin recommended by the Invasive Animals CRC to control foxes is designed to have an anti-toxin available in cases where dogs are the unintended targets. There is a window of opportunity to treat a dog but this is limited to an hour or two after ingestion.

Pets found in the Sanctuary or caught in feral animal traps: When a dog or cat that appears to be a domestic pet is found roaming free, or is caught in a trap set-up to capture dogs or cats, it will be captured and returned to its owners, via the ACT Government pound or RSPCA facility.

Restoration Actions

Fire

SoilSites 210Fire is a critical ecological process in temperate woodlands. However, since European settlement, fire regimes have been largely disrupted.

As part of the restoration actions, we have experimentally burned research sites in Goorooyarroo during Winter 2011, with assistance from hundreds of ACT Government staff.

Partners in the Mulligans Flat-Goorooyarroo Woodland Experiment are now monitoring the response of the woodland ecosystem.

Results from the research will inform how the ACT Government manages woodlands throughout the Territory.

Bringing back lost species through reintroductions

The Species Management Panel has identified five species that are appropriate for reintroduction in 2010 – 2015:

Eastern Bettong (Bettongia gaimardi)

The Tasmanian or Eastern Bettong was once widespread in the southeast of mainland Australia. They were once so abundant in the Canberra district that they were considered an agricultural pest, but became extinct soon after 1900 following the spread of the fox. Bettongs feed primarily on underground fungi and tubers. Their digging and transport of soil microorganisms plays a central role in soil health.

Reasons for reintroduction:
• Fundamental role in rejuvenating soils that underpin the entire woodland ecosystem.
• Establish a mainland source of animals for further reintroductions, thereby eliminating the need to draw on the wild Tasmanian population in the future.
• Insurance population should foxes become established in Tasmania

Progress
A reintroduction plan has been developed and translocation of animals from Tasmania commenced in 2011 in collaboration with the Tasmanian Park Service (Department of Water, Primary Industries and the Environment). The first bettongs were received at Tidbinbilla Nature Reserve during the second half of 2011. An ARC Linkage Grant to ANU, the ACT government and CSIRO has been awarded to support research in the reintroduction of the bettong ($1.84 million cash and in kind over four years).

Eastern Bettongs were re-introduced to the Sanctuary in 2012.

Eastern Quoll (Dasyurus viverrinus)

The Eastern Quoll is a small marsupial carnivore closely related to the Tasmanian devil. Once found across south-eastern Australia, they are now only found in parts of Tasmania due to predation by foxes and competition for food with cats. Often nicknamed the ‘native cat’, quolls have fantastic climbing and hunting abilities  and will hunt for anything from insects to rabbits. Females give birth to up to 30 babies – but only have 6 teats. So it’s first in- best dressed for the first 6 babies that latch onto a teat. Survival of the fittest at work.

Reasons for introduction
• Being carnivorous the quolls are filling a vital hole in the food-web.

• Species insurance with numerous populations in case of disease or disaster.

Progress
In 2016, the Eastern Quoll was reintroduced into Mulligans Flat after a 50 year absence. To keep the genetics strong – half were sourced from Tasmania and half from Mt Rothwell – a captive breeding facility in Victoria. Being great climbers – once reintroduced some did climb over the fence, however, all of the females that stayed in the sanctuary bred within the first few months of living here.

More reintroductions will take place in 2017.

Bush-Stone Curlew (Burhinus grallarius)

A species typical of box-gum grassy woodlands that has suffered a large contraction of distribution from habitat loss and simplification, and most importantly, fox predation. Individuals were last seen in Canberra in 1970s. Feeds on invertebrates, frogs, lizards, snakes, seeds.

Reasons for reintroduction
• Where the fox population is eliminated, there is a good chance of re-establishing a population.
• An iconic species of box-gum woodlands – easily heard and seen.
• Build a source population for further reintroductions to the region. • A species that may be able to colonise the surrounding landscape if fox control measures in place.

Progress
11 birds were reintroduced in 2014, unfortunately some flew over the fence and were taken by foxes or cats. However, that year the very first Bush-Stone Curlew chick born in the ACT region was born at Mulligans Flat. In 2015 and 2016, we learnt from our mistakes and conducted a soft release (the birds were released into an aviary onsite). Once they knew this was their home released them into the sanctuary. To our knowledge, using this method we have had 100% success. The reintroduction of curlews will be an ongoing program.

New Holland Mouse (Pseudomys novaehollandiae)

Photograph by Tim Bawden

The New Holland Mouse has all but disappeared from the southern and drier inland parts of its distribution. First described in 1842, it was thought to be extinct until 1967. Although it has not been seen in the Canberra region during recent times, it has been commonly recorded in 100+ year old bone deposits formed from the regurgitated remains of owl prey. It eats seeds, insects and other plant material and large populations could have significant ecological impact.

Reasons for introduction
• In the absence of predation by feral animals (predators?) it may persist in less recovered habitat than larger-bodied species.
• A good study species for the role of small species in habitat recovery, and the potential for reintroductions into former habitats that are very different from the habitats of surviving wild populations.

Progress
Reintroduced over summer of 2012/2013, current ANU honours students are studying the survival and behaviour of the species.

Brown Treecreeper (Climacteris picumnus)

The Brown Treecreeper is a small sedentary passerine, which breeds cooperatively in gregarious groups composed of the breeding pair and a number of offspring helpers. This species is one of many woodland birds that are rapidly declining, particularly in fragmented or isolated habitats. The Brown Treecreeper is listed as vulnerable under the NSW Threatened Species Conservation Act 1995 and also under the ACT Nature Conservation Act 1980.

Reasons for Reintroduction
• Establishment of a self-sustaining population of Brown Treecreepers.
• Intensive monitoring of released birds in an experimental framework.
• Extensive habitat restoration of the host environment.
• Enhanced understanding of factors influencing the success of reintroductions.

• Unique test of habitat selection theory through examination of how animals released in unfamiliar environments select habitat.

• Providing a model for future translocations and superior reserve management.

Progress
Forty-three Brown Treecreepers were released into Mulligans Flat and Goorooyarroo reserves, between 16 Nov and 1 Dec 2009. Family groups were released together, with 18 birds having radio transmitters fitted as part of an ANU PhD project. The birds were monitored daily until early February 2010. Two groups, each of three specimens were established in or near the reserve and have continued through into 2011. Further monitoring is required before it can be concluded that the birds have re-established a viable population in the area.

Southern Brown Bandicoot (Isoodon obesulus)

Once widespread, now confined to small populations. Was so numerous in Canberra region, farmers laid snares to catch it. An important ecosystem engineer that turns over soils and moves fungal spores and soil microorganisms. Feeds on fungi, roots and tubers.

Reasons for introduction
• Fundamental role in rejuvenating soils that underpin the entire woodland ecosystem.
• Source population for other reintroductions.

Progress
Pending assessment of reintroduction outcomes for other species.

Rosenburg’s monitor (Varanus rosenbergi)

These reptiles are carnivorous and eat carcasses, small mammals, birds, eggs and other reptiles. Unlike the lace monitors, Rosenburgs spend their time on the ground and are a very cryptic species. Their major threats are predation by dogs, cats and foxes and removal of fallen timber which they use as shelter. Lucky for the monitors, we introduced 2000 tonnes of logs back into the sanctuary after hundred of years of fallen timber removal. Not only does fallen timber provide nutrients to the soil, it also provides shelter to animals like the Rosenburg’s monitor.

Reasons for introduction
• Important role in the food-web
• Source population for other reintroductions.

Progress
Pending assessment of reintroduction outcomes for other species.