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Native plants and animals in the Flinders–Olary and Gawler bioregions of northern South Australia have been adversely affected since European settlement. Impacts from high levels of grazing by domestic stock and other introduced grazers such as rabbits, feral goats and (to a lesser extent) donkeys and camels have been long term.
Excessive grazing pressure has prevented native plant communities from regenerating, allowing exotic plants to colonise and establish. In some areas this has led to fragmentation of ecosystems. Combined with predation by foxes and feral cats, these changes have significantly reduced local fauna, with some species such as the bilby, bettong and hare-wallabies now believed to be extinct. The Bounceback program was developed to protect the area from further damage and to help it recover.
The focus of this case study is on the fox control component of the Bounceback recovery program. However, fox control is only one of many conservation and threat-abatement activities happening across a range of land tenures, addressing various goals to restore the plants and animals.
Initially focusing on reducing the threats to yellow-footed rock-wallabies, fox baiting began on two pastoral properties in the Olary Ranges in 1991 and the Flinders Ranges National Park (FRNP) in 1993. The program then expanded to include all of the park and adjacent buffer areas on surrounding pastoral properties. The focus also moved from a single species to a broadscale recovery initiative. In 2000, the program continued its expansion into the Vulkathunha–Gammon Ranges National Park and Gawler Ranges National Park.
The broad aims of the Bounceback program are to:
From these general aims, a series of more specific objectives has been established for different sites. Removal of foxes and other pest animals and plants has been a priority to reduce their adverse impacts, and encourage broadscale recovery of native species in the system.
Foxes are baited using a combination of ground-based and aerial bait delivery from a fixed-wing aircraft across extensive areas, both on- and off-reserve. A lot of the target area is difficult to access, so aerial baiting allows more effective coverage of critical areas for wallaby protection. It also improves the program’s efficiency in terms of time and cost. Dried meat baits containing 1080 poison (monosodium fluoroacetate) are manufactured and used by the project team.
Aerial baiting allows more effective coverage of critical areas for wallaby protection
In the original program, the area was baited twice per year (autumn and spring) at a rate of 8–10 baits/km2. In 1995, after reviewing results from Western Australia programs, this was increased to four times per year, with a target rate of 5 baits/km2. The majority of ground baiting is done via quad bikes, with tracks baited from vehicles.
The success of the program is measured by monitoring ‘process’ and ‘response’ indicators. Process monitoring tracks the operational progress of control activities (eg measuring fox abundance in response to baiting). This determines how effective the control methods are and links cause to effect.
Response monitoring looks at recruitment and survival of indicator species, including threatened native species (eg yellow-footed rock-wallaby, echidna and short-tailed grasswren) and more common species (eg kangaroos and emus). This monitoring assesses the ecological outcomes of the program.
One of Bounceback’s long-term aims is to reintroduce species such as bilbies and bettongs into selected areas, to show how effective the threat abatement programs have been.
Ongoing support and involvement of landholders and the community has been critical and has been one of the reasons the program has succeeded in achieving a coordinated approach to land management.
At present, fox-baiting programs are delivered across multiple landholdings covering an area of about 5500 km2. Spotlight monitoring has shown that fox numbers in the baited areas have been kept lower than 1 fox/100 km — this compares with an average 10 to 20 foxes/100 km in unbaited areas.
Yellow-footed rock-wallaby populations have significantly increased in response to the combination of threat abatement activities such as feral goat control and fox control. The many colonies that were at risk of local extinction are now considered secure (at least in the medium term) where active management is taking place. Population estimates in FRNP controlled areas have increased from fewer than 50 wallabies in 1993 to nearly 1000 animals in 2009. In unmanaged areas, the wallaby numbers have not shown the same population growth and there has even been some extinction of colonies.
Short-tailed grasswren populations have also increased in managed areas in the Flinders Ranges. They are now able to live in areas of lower habitat quality with reduced spinifex (Triodia) cover, largely due to fox control.
There are also signs that malleefowl are recovering within the Gawler Ranges, with increased activity of malleefowl mounds and signs of chicks hatching.
One of the reasons this program has been successful is the partnerships with landholders and the community. These enable a coordinated approach to managing threats and restoring landscapes. A landscape-scale approach has also been fundamental to the program’s success, resulting in effective fox control and preventing reinvasion of foxes into baited areas.
Concerns about non-targets being poisoned by the fox-baiting program, including working dogs on pastoral properties, continue to be an issue for some people. To address this, a comprehensive non-target risk assessment has been done and landholders are kept informed about baiting programs, including target bait areas and bait-exclusion zones.
Partnerships with landholders and the community enable a coordinated approach to managing threats and restoring landscapes
The initial fox baiting was conducted twice a year, but results from Western Australian experiments aimed at optimising baiting regimes for arid environments indicated that this may not be frequent enough. The program was subsequently increased to four baitings per year.
Due to the rugged and inaccessible nature of the terrain, ground-based delivery of fox baits along roads and tracks did not provide as effective bait coverage as aerial delivery. Bait delivery by plane is now used twice each year, in between ground-based baiting programs.
These points demonstrate the importance of taking an adaptive approach to management and modifying program methods as new information emerges or techniques become available.
This case study has demonstrated how a coordinated landscape-scale approach to fox baiting has reduced the impact of predation on native fauna and improved biodiversity in the semi-arid rangelands of South Australia.
Aerial delivery of dried meat baits has been more cost and resource effective than ground baiting and enabled fox control across rugged and inaccessible terrain.
Typical terrain and habitat of the fox baiting target area. Image: Keith Bellchambers
Pestsmart Toolkit for European foxes
Invasive Animals Ltd has taken care to validate the accuracy of the information at the date of publication [November 2011]. This information has been prepared with care but it is provided “as is”, without warranty of any kind, to the extent permitted by law.