By Dr Michael Smith, South-west Regional Ecologist
When cats and foxes were introduced to Australia, the fate of more than 20 mammal species was cast and extinction was inevitable. Feral cats alone are estimated to kill more than six million animals every night across Australia. For many species (mammals, birds and reptiles alike) declines are occurring, leaving the biodiversity of this unique continent worse off.
People value wildlife for many different reasons, but ultimately our wellbeing is reliant on our flora and fauna. Whether it is for health and recreational benefits, aesthetic beauty, provision of resources or cultural and educational significance, we can all derive substantial wellbeing from our natural world.
Conserving and restoring Australia’s native wildlife is important, and the primary objective of Australian Wildlife Conservancy. Enter Mt Gibson. This 132,000-hectare wildlife sanctuary was once a hotspot for small native mammals — believed to be a consequence of its position in a transition zone between two major biomes, the wetter south- west and the more arid north. With the introduction of feral predators, many of the small mammal species disappeared from the area, leaving a comparatively depauperate fauna.
A great conservation success story
As a national leader in translocations, AWC set to work restoring the mammal fauna of Mt Gibson. A large 7,800-hectare safe haven was established, from which all cats and foxes were removed by 2015. Eight mammal species have since been reintroduced into the area: Brush-tailed Bettongs (Woylies, Bettongia penicillata), Greater Bilbies (Macrotis lagotis), Numbats (Myrmecobius fasciatus), Red-tailed Phascogales (Phascogale calura), Western Barred or Shark Bay Bandicoots (Perameles bougainville), Shark Bay Mice (Pseudomys fieldi), Greater Stick-nest Rats (Leporillus conditor) and Banded Hare-wallabies (Lagostrophus fasciatus).
Five years on from the removal of the last cat, and with additional funding from the Northern Agricultural Catchments Council and the National Landcare Program, seven of these species are breeding and spreading across the safe haven (the Shark Bay Mouse is proving more cryptic), even though the project is still in its early days. This is an internationally significant conservation success story and represents the first time that any Australian organisation has restored eight threatened mammals to a single site.
Looking beyond the fence
Two more locally extinct species are set to be reintroduced over the next few years, Chuditch (Western Quoll, Dasyurus geoffroii) and Brushtail Possums (Trichosurus vulpecula). Chuditch are a wide- ranging predator and are therefore better suited to release outside of the fence. Brushtail Possums are better able to withstand predation by cats and foxes than many other species and we plan to release them inside and outside the fenced area.
AWC is preparing a ‘beyond the fence’ strategy that, if successful, will see the re-establishment of Chuditch and Brushtail Possums into the larger sanctuary outside the conservation fence. This is incredibly important work that will eventually allow the species re-established in the safe haven to disperse and persist in the broader sanctuary. A large array of 90 cameras has been established across 20,000 hectares outside of the safe haven and will be used as the initial cat and fox management area.
A second array of 30 cameras has been installed across a 6,000-hectare area, which will be used as an untreated ‘comparison’ site. The cameras provide us with a detailed understanding of the existing native fauna. We are already collecting valuable data on species such as Brush-tailed Bettongs and Malleefowl (Leipoa ocellata). The cameras will allow us to estimate the activity levels of cats, foxes, dogs and other species. After 10 months of initial monitoring in the treatment site, an aerial cat baiting program was conducted in June 2020 (no foxes were detected in the treatment area). Later in 2020, cat and fox activity will be assessed post-baiting. This information will be used to adaptively manage our cat and fox control efforts with a view to releasing radio-collared Chuditch and Brushtail Possums in 2021-22.
This is a major management program that, if successful, will be a huge step towards re-establishing a significant component of Western Australia’s Wheatbelt mammal fauna.
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