Securing the future of endangered species in WA

Opportunity

Australia has the highest level of mammal extinction in the world. Since non-native species were introduced to Australia, more than a hundred native species of flora and fauna have been officially declared extinct [1].

Research has pointed to a number of factors, including changes in fire regimes, competition with introduced species, disease, extreme weather and introduced predators, with foxes and feral cats especially detrimental for mammal reintroduction programs [2, 3]. Feral animal eradication is generally recognised as impractical in Australia as they tend to repopulate after targeted baiting and culling [4]. Haven areas, such as islands or fenced zones free of introduced predators are therefore essential to avoiding the extinction in the near-to-medium term of at-risk native species [5].

AWC identified fenced feral-free zones as an important measure to combat native species extinction.

Approach

In 2001, AWC acquired a 131,812-hectare property at Mount Gibson around Lake Moore, previously a sheep station. Straddling the border between the Wheatbelt and the Mid-West regions, AWC turned the property into a wildlife sanctuary. After several years of working to protect native wildlife, AWC embarked on an ambitious project to build a 43-kilometre feral-proof fence around a 7,838-hectare area, completely eradicating all feral predators inside. As the largest feral-predator free area on mainland Australia, the focus of the site was to reintroduce regionally extinct mammals with the goal to establish wild, self-sustaining populations of at least 10 species.

As well as providing a safe environment for native species, the project aimed to build and share conservation-related knowledge. This was achieved through the construction of a dedicated field research station and a unique public education program facilitated through a campground and nocturnal walks.

Impacts and outcomes

AWC’s Mt Gibson Endangered Wildlife Restoration Project delivers vital conservation outcomes for Australia’s critically endangered species.

As of September 2021, eight regionally extinct mammal species have been reintroduced into the fenced area; the Brush-tailed Bettong (Woylies, Bettongia penicillata), Greater Stick-nest Rat (Leporillus conditor), Numbat (Myrmecobius fasciatus), Greater Bilby (Macrotis lagotis), Red-tailed Phascogale (Phascogale calura), Western Barred or Shark Bay Bandicoots (Perameles bougainville), Banded Hare-wallabies (Lagostrophus fasciatus) and Gould’s Mouse (Pseudomys fieldi).

Currently, AWC is reintroducing Brushtail Possums (regionally extinct since the early twentieth century), building on years of predator control and research. The final reintroduction of the project, the Western Quoll (Chuditch, Dasyurus geoffroii), is planned for mid-2023.

The population of reintroduced species is growing well, and the project is having an impact beyond the Mt Gibson sanctuary.

To support reintroductions, AWC undertakes ongoing biodiversity surveys, scientific research, land management and public education programs.

What worked

Feral proof areas have been a successful strategy

Seven of the eight reintroduced species have been successfully identified as having increased in population size and/or expanded their range post-release, reflecting strong growth in population size and density. The exceptional success of this conservation project is internationally significant and represents the first time an Australian organisation has restored eight threatened mammals to a single site.

What didn't work

Trialling species monitoring techniques

The project has included various learnings in terms of post-release species monitoring techniques. For example, red-tailed phascogales have previously been difficult to monitor at Mt Gibson using lured camera traps. Other accepted survey methods such as ‘Elliot traps’ on ground are not suitable at Mt Gibson as they also attract larger species such as woylies and shark bay bandicoots. To overcome this, AWC trialled cameras in trees to monitor wired open/baited ‘Elliot traps’ at eight sites inside the fenced area. This strategy was successful and provides critical information for future use.

REFERENCES 

1. Department of Agriculture, W.a.t.E. Threatened species & ecological communities. 2021 [cited 2021 8 August]; Available from: http://www.environment.gov.au/biodiversity/threatened.
   
   
2. Burrows, N., et al., Controlling introduced predators in the Gibson Desert of Western Australia. Journal of Arid Environments, 2003. 55(4): p. 691-713.
   
   
3. Subroy, V., A.A. Rogers, and M.E. Kragt, To bait or not to bait: a discrete choice experiment on public preferences for native wildlife and conservation management in Western Australia. Ecological Economics, 2018. 147: p. 114-122.
   
   
4. Burrows, N.D., Feral animals in the semi-arid and arid regions of Australia: origins, impacts and control, in On the Ecology of Australia’s Arid Zone. 2018, Springer. p. 331-373.
   
   
5. Legge, S., et al., Havens for threatened Australian mammals: the contributions of fenced areas and offshore islands to the protection of mammal species susceptible to introduced predators. Wildlife Research, 2018. 45(7): p. 627-644.