Western Shield, managed by Western Australia's Department of Environment and Conservation, is a nature conservation program, safeguarding Western Australia's animals and rescuing them from extinction. Set out in 1996, it is the largest and most successful wildlife conservation program ever undertaken in Australia, as of 2009.
Between the 1920s and 1950s scientists synthetically developed a poison called sodium fluoroacetate (commonly called 1080 poison), for use in biological warfare. Subsequently it was found that sodium fluoroacetate grew naturally in many plants of the south-west of Western Australia and many of the native mammalian herbivore fauna of the region had evolved with a natural tolerance to the poison. The plants, in the genus Gastrolobium, are commonly called "poison pea"; farmers often suffer livestock fatalities due to wandering animals that unfortunately wander into and graze the deadly plants.
During the late 1980s a conservation program relating to fox control - Fox Glove - commenced using dried meat baits and sausages laced with 1080 poison. Fox Glove was very effective by allowing native species' populations to increase due to the local eradication of introduced predators, namely foxes and feral cats, although the control of feral cats is much more difficult as the cats favour live prey. Poison coated oats and carrots are occasionally used to control herbivorous invasive species, including rabbit and rats.
Since 1996, when Western Shield was initiated, a Beechcraft Baron flies 55,000 km every three months, to drop the 770,000 1080 poison baits, into most national parks, nature reserves and state forest of the south-west of Western Australia, covering an area greater than half the size of Tasmania.
The baiting, aimed for all introduced predators, but unfortunately primarily targeting only foxes, lead to a huge increase in native species populations in the 1990s. The natural recovery of species, for example, trap success rates for medium-sized mammals (particularly Woylies) in the Jarrah forest of Kingston Block, near Manjimup, revealed a sevenfold increase in native mammals since baiting began in 1993 in the following five years. Complimenting the natural recovery of species has been the conservation induced reintroductions and translocations. Theses involve reintroducing native species into ecosystems where they were previously found but have since become locally extinct, then Western Shield could either reintroduce animals from breeding programs, or directly translocate the animal from high self-sustaining populations elsewhere in the south west. Western Shield has carried out many translocations, both to other DEC managed lands, to the privately owned conservation sanctuaries of the Australian Wildlife Conservancy, or to other state’s conservation lands, or even islands.
Since 1996 over 80 translocations have taken place within Western Australia, with over 20 species (15 mammal species, 3 bird species, and a few reptile species) involved. The translocations have not only occurred in the southwest forests but also the Monte Bello Islands, the Pilbara, Kalbarri, Shark Bay, islands off of Adelaide., outback New South Wales, and the central deserts of Australia.
Species taken off the endangered species list
Western Shield has been so successful that three native mammal species have been taken off the list of Western Australia's list of threatened fauna – through the Wildlife Conservation Act 1950. The species taken off "Schedule 1 – Fauna that is rare or is likely to become extinct" were the Quenda (Isoodon obesulus), the Tammar Wallaby (Macropus eugenii) and the Woylie (Bettongia penicillata). The Woylie was also taken off the list of Australia’s threatened fauna – through the Environment Protection and Biodiversity Conservation Act 1999, it was demoted from the "Endangered" Category and is not even on the list any longer as it is not deemed in ‘danger of extinction’. The Woylie was also taken off the "IUCN Red List of the World’s Threatened Fauna" as "Endangered" and downgraded to "Lower Risk / Conservation Dependent". Western Shield’s success for having the Woylie de-listed as "Endangered" on the state, national, and international levels is a first for any species in the world to be taken off either the state, national, or international level of ‘Threatened Species’ due to successful wildlife conservation efforts.
Recent declines in native species
Unfortunately the success story of Western Shield, is no longer, as the Woylie has been quickly added back to WA’s list of threatened fauna, due to the sharp declines since 2002, with some places having a 95% decrease in that locality near the Upper Warrer in Manjimup, where the original ‘seven fold increase’ occurred. The Woylies population across all of Australia, have declined, especially the DEC managed lands of the South west forests, and even wild populations (thanks to previous translocations) in South Australia, have also mysteriously declined, with the culprit possibly being disease. In fact quite a few other species of the south west forests have also declined, with no definite answers many studies are being undertaken, including through DEC’s ‘Saving our Species’ new initiative. Although early days yet, hopefully conclusions can be made, but even then so, what will be eventuated from knowing the quandary, we will have to see. Possible explanations include, global warming, ground water loses, introduced predators building up a resistance to the baits, a natural population fluctuation or possibly even by natural means, such as nowadays more native predators such as Carpet Pythons and Chudicthes are surviving, only to ultimately endanger other native species. Hopefully the cause will be found, and a suitable solution will be resolved.
Gilbert's Potoroo significant recovery
Western Shield has saved many species from extinction, most timely the Gilbert's Potoroo, after it was ‘lost’ for over 100 years only to be rediscovered in 1994 in Two Peoples Bay Nature Reserve, near Albany, with a population probably less than 30. Western Shield’s Gilbert’s Potoroo subdivision, led by Dr. Tony Friend, now has a self sustaining mainland wild population, a breeding centre ‘back up’ stock with a cross fostering program with Long-nosed Potoroos exemplifying the marsupial birthing sequence and also an island paradise home to breeding animals on Bald Island. Although still below 40 animals, the critically endangered Gilbert’s Potoroo is in safe hands and is well on the road to recovery.
Although Western Shield’s publicised success has diminished, and so too some populations of native species in the latter 2000s, Western Shield is still at the utmost forefront in the conservation of native species, continually studying and refining their methods with the dream of a successful feral cat bait possibly eventuating quite soon. Many exciting frontiers expect to be confronted with the continuation of Western Shield, including the desert regions, further studies and developments, the creation of effective cat bait, biological invasive species control, and the increase in numbers of endangered species, returning WA, to the biodiverse haven it was prior to European settlement.
- "Western Shield". Department of Environment and Conservation. Retrieved 2008-02-17.
- Possingham,Hugh; Jarman, Peter and Allen Kearns. (2004) A review of the Western Shield Program. Conservation science Western Australia, Vol.5, no.2 (Dec. 2004), entire issue.
- Bouncing back Landscope, Spring 1998, p. 28-35,