Key words. Feral-proof fence, native animal reintroductions, feral animal control.
Introduction. Arid Recovery is a conservation research initiative based in the South Australian arid zone and dedicated to the restoration of Australia’s arid lands. Established in 1997, the program is centred around a 123km² fenced reserve but it is continually expanding into the wider region. Feral cats, rabbits and foxes have been eradicated from a total of 60km² and this has provided an area of complete protection into which four species of locally extinct mammals have so far been reintroduced.
Although the fenced reserve provides a core area for animal re-introductions, the long term aim of Arid Recovery is to develop broadscale control techniques for feral animals to facilitate the restoration of the entire arid zone ecosystem including re-introducing herbivores, predators and insectivores to create a natural functioning ecosystem that requires minimal management. Specific goals include to:
- eradicate feral cats, foxes and rabbits and re-establish native species,
- research and monitor the processes of ecological restoration and provide transferable information and techniques for broadscale management of Australia’s arid lands
Arid Recovery is also committed to increasing education and awareness of arid zone issues and has an education program that includes indigenous youth and local schools.
Degradation. At least 27 species of native mammal once inhabited the Roxby Downs region but over 60% have become locally or completely extinct since European settlement. Some bird species such as the Bush Thick-knee and Plains Wanderer have also become locally extinct or endangered.
The main reasons for the decline of the local native fauna and flora are overgrazing by rabbits and domestic stock, and predation from introduced animals like the feral cat and fox. Medium-sized desert mammals have been most affected with many now globally extinct or have disappeared from mainland Australia and survive only on off-shore islands.
Since the inception of grazing in arid rangelands, there have been extensive vegetation changes. Many parts of arid Australia were severely over-grazed by sheep and cattle during the advent of pastoralism in the 19th Century. Overgrazing by domestic stock and rabbits has a significant effect on arid zone vegetation; long-lived arid zone trees and shrubs are prevented from regenerating, and long-lived plant species are being replaced by short-lived annual and weed species. Whilst current pastoral practices are much more conservative there are still many areas degraded by pastoralism.
Our restoration work. A feral-proof fence has been designed and installed to protect a total area of 123km². The fence was built in blocks and to date, 123 square km of arid land has been fenced and control programs implemented for rabbits, cats and foxes (Fig 1.) . Six locally-extinct threatened species were reintroduced: Greater Stick Nest Rat (Leporillus conditor), Burrowing Bettong (Bettongia lesueur), Greater Bilby (Macrotis lagotis), Western Barred Bandicoot (Perameles bougainville), Numbat (Myrmecobius fasciatus) and Woma Python (Aspidites ramsayi). (See results below.)
Monitoring. More than 500 monitoring sites have been established to document the restoration process including annual pitfall trapping, burrow monitoring, seedling counts, photopoints and spoor counts. Recruitment of seedlings is monitored inside and outside the Arid Recovery Reserve to determine the impact of rabbits and domestic stock on the survival of seedlings.
Results of our work.
- Rabbits, cats and foxes have been eradicated from 60 square km pf the Arid Recovery Reserve.
- Four of the mammal species (Greater Stick Nest Rat, Burrowing Bettong, Greater Bilby and Western Barred Bandicoot) were successfully reintroduced. The Numbat and Woma Python reintroductions were unsuccessful,
- The fence design has now been adopted by many projects both within Australia and internationally (e.g. Hawaii, Queensland). Results from 10 years of pitfall trapping show that native rodents have now increased to 10 times inside the Reserve compared to outside areas where cats and foxes are still present.
- Results of the monitoring of plant recruitment to date suggest that survival of Mulga (Acacia aneura) seedlings is much higher where rabbits and grazing pressure by other herbivores has been removed.
Research program. Where published information or advice was not available, Arid Recovery implemented its own research programs to test various on-ground techniques and then adopted the most effective methods. Arid Recovery’s four co-founders are all ecologists and have ensured that all management and monitoring has an adaptive management focus and that overall ecosystem restoration is more important than single species recovery.
The University of Adelaide is a partner organisation and has provided research students, scientific advice and staff management. Research into effective rabbit and cat control methods has now been published for use by other land managers. Research has been conducted into the ecosystem services provided by re-introduced Bilbies including the increased soil carbon levels and water infiltration recorded within their foraging pits.
Long term monitoring sites have provided critical information on both fauna and flora recovery of in situ species and an insight into their threatening processes. More than 40 scientific papers, internal reports and theses and 25 conference presentations have been produced to date and Arid Recovery is committed to effective dissemination of information to landholders not just the scientific community. Publications in National Landcare Magazine and participation in local NRM fora ensure that the scientific information is transformed into easily digestible and practical land management applications.
Further directions. Arid Recovery is now researching ways to move beyond the fenced reserve through improved predator management and increasing the predator-awareness of threatened species. Another current and future direction is preventing overpopulation of reintroduced species within the reserve through the use of one way gates and predators. Arid Recovery has recently partnered with Bush Heritage to form the South Australian Rangelands Alliance (SARA) with both organisations aiming to restore the plants and animals in the arid zone.
Lessons learned. The partnership between industry, government, community and research institutions has been integral to the success of Arid Recovery. Each partner has brought skills, resources and expertise to the program and ensured a balance is achieved in ecological restoration activities.
The winning combination of solid on-ground works and adaptive management based on sound scientific research is the key to Arid Recovery’s success. By ensuring that effective monitoring is regularly conducted and reviewed, Arid Recovery staff are able to implement changes to reserve management effectively and quickly.
Another important lesson learned is that restoration does not happen on its own, it requires long hours of hard work from both staff and volunteers. Arid Recovery is indebted to the hundreds of people who have given up their time to shoot cats, trap rabbits, count birds, measure plants and most importantly erect fencing.
Stakeholders. Arid Recovery is a partnership between BHP Billiton, S.A. Department for Environment, University of Adelaide and the Friends of Arid Recovery. All four partners contribute funding and in kind contributions and have committed to long term support for the program.
Contact. Please contact Arid Recovery for more information on : (08) 8671 2402 or www.aridrecovery.org