|Scientific Name:||Bettongia penicillata Gray, 1837|
The taxonomy of Bettongia penicillata is unsettled. The species was once the most widespread of any member of the Potoroidae with records from all mainland States and the Northern Territory (Start et al. 1995). It is possible that the two subspecies represent distant ends of clines that terminated in southeastern Australia (subspecies penicillata), southwestern Australia (subspecies ogilbyi) and northern Queensland (B. tropica, originally described at a subspecies of B. penicillata). Bettongia penicillata penicillata is Extinct. Bettongia penicillata ogilbyi is Critically Endangered.
|Red List Category & Criteria:||Critically Endangered A2ce ver 3.1|
|Assessor(s):||Woinarski, J. & Burbidge, A.A.|
|Reviewer(s):||Johnson, C.N. & Hawkins, C.|
|Contributor(s):||Wayne, A., Morris, K., Groom, C., Copley, P., Dixon, J., Legge, S. & Short, J.|
The Woylie has suffered a >90% reduction in population size over the past 10 years and the decline is continuing.
|Previously published Red List assessments:|
Formerly very widespread, Woylies occupied most of semi-arid and arid Australia, mostly south of the tropics, including the arid and semi-arid zones of Western Australia, the Northern Territory, South Australia, New South Wales and Victoria, and possibly extended north along the east coast into Queensland, the remnant of this population now being accepted as Bettongia tropica. Woylies also occurred on Saint Francis and St Peter Islands, South Australia (Robinson et al. 1996). Burbidge et al. (2009), using modern, historical and subfossil records, found that Woylies (excluding B. tropica) are known to have occurred in 28 of Australia’s 85 bioregions and that they are now extinct in all but two.
By 1970, they remained only in four subpopulations in south-western Australia: Dryandra, Tutanning, Kingston and Perup. Pacioni et al. (2011) used a molecular approach (12 microsatellite loci and mitochondrial DNA) to investigate relationships between these subpopulations.
In 1975, the South Australian National Parks and Wildlife Service began a breeding program for the species at Para Wirra Recreation Park from animals sourced from Perth Zoo with the goal of providing stock to re-establish the species in South Australia. The first experimental releases were onto two small islands, Bird Club Island (8 ha) in 1979 and Venus Bay ‘Island A’ (15 ha) in 1980, followed by three larger islands, St Francis Island (809ha) in 1980, St Peter Island (3493 ha) in 1981 and Wedge Island (947 ha) in 1983 (Delroy et al. 1986, Freegard 2008, Yeatman and Groom 2012). Woylies did not survive on Bird Club Island, probably due to foxes accessing the island. Neither did they survive on St Francis Island (reasons unknown) (Robinson et al. 1996). These translocated Woylie subpopulations are genetically depauperate (Pacioni 2010), having been derived mostly from the small Para Wirra founder group.
There have been numerous reintroductions to parts of the south-west of Western Australia and some to New South Wales, but some have failed in the medium- to long-term (Priddell and Wheeler 2004, Wayne et al. 2011; Yeatman and Groom 2012). Remaining unfenced subpopulations from these reintroductions in Western Australia are Julimar Forest (1995-2011), Avon Valley National Park (2002-2004), Boyagin Nature Reserve (1992), several sites in the northern and central jarrah forest (the current status of some of these is unknown), Batalling Forest (1982), and North Karlgarin Nature Reserve (2005).
|Range Map:||Click here to open the map viewer and explore range.|
Accounts by early settlers (e.g. Facey 1981) and Aboriginal people (e.g. Burbidge et al. 1988) demonstrate that Woylies were once abundant. In arid Australia Woylies declined after European settlement and survived the establishment of the feral Cat, but disappeared soon after the establishment of the Red Fox (Burbidge et al. 1988). Abundance in the four remnant Western Australian wheatbelt subpopulations has varied, with Sampson (1971) at Tutanning and Christensen (1980) at Perup finding numbers to be relatively high during the 1960s and 1970s. However, numbers fluctuated, e.g. Kinnear et al. (2002) found Woylies to be rare at Tutanning in 1984. Trap success rates at Tutanning increased from c. 2% in 1984 to c. 28% in 1992 following the implementation of fox control (Wayne et al. 2010). Following the introduction of widespread fox control under ‘Western Shield’ in 1996, Woylie numbers rapidly increased at all four of the original locations and translocations were conducted to several sites in the northern jarrah forest and wheatbelt in Western Australia, a total of 46 translocations in all, and to sites in eastern Australia (Wayne et al. 2008).
From about 2000, there was a significant decline in all free-ranging Woylie populations, natural and reintroduced (Groom 2010). At a species level Woylies were found to have declined by c. 90% from a peak of c. 250 000 individuals in 1999 to 33 000 in 2010. The largest subpopulation, at Upper Warren, declined by 95% from an estimated peak of 215 000 in 1999 (Wayne et al. 2011). A major research program coordinated by the Western Australian Department of Parks and Wildlife investigated the reasons for the decline including predation (Wayne et al. 2011; 2013; N. Marlow and P. de Tores pers. comm.) and disease (e.g. Botero et al. 2013), with several further papers yet to be published.
Forty-one Woylies were translocated to the Perup Sanctuary mainland island in October-December 2010. In November 2012, 161 independent Woylie individuals were captured but due to trap saturation (80 traps x 4 nights) an accurate estimate could not be achieved. The number is probably around 200 (A. Wayne pers. comm.).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Woylies originally inhabited a wide range of country. In the western deserts, Aboriginal people reported that they occupied sand plains and dunes with spinifex (Triodia spp.) hummock grassland. The remnant subpopulations in south-western Australia inhabit woodlands and adjacent heaths with a dense understorey of shrubs, particularly Gastrolobium spp., which contain monofluoroacetic acid, the compound present as sodium monofluoroacetate in the vertebrate pesticide ‘1080’. Diet is largely underground fungi, although it includes tubers, bulbs and seeds. Woylies can store seed in their cheek pouches for later caching and are a major distributor of fungal spores and seeds (Murphy et al. 2005). Their digging also has a positive impact on the non-wetting property of soils (Garkaklis et al. 1998).
They are solitary animals but nest sharing (usually mother and young at heel) has been recorded (Sampson 1971, Christensen and Leftwich 1980, Start et al. 1995). They occupy home ranges, the size of which varies between habitats, sites and according to Woylie density. Small home ranges (less than 6 ha) are generally observed at high density occurrences (Nelson 1989 in Nelson et al. 1992; Hide 2006). Males tend to have larger home ranges than females (Sampson 1971, Leftwich 1983), although this is not always so when Woylies are at higher densities (Yeatman 2010).
|Generation Length (years):||4|
|Movement patterns:||Not a Migrant|
|Major Threat(s):||The major reason for past decline has been predation by Red Foxes and feral cats, exacerbated in the deserts by changed fire regimes. The recent crash in numbers is thought to be primarily due to feral cats, although exotic disease may be involved. Inappropriate fire regimes may exacerbate fox and cat predation.|
Hall et al. (1991) was the first edition of the Woylie Recovery Plan and guided work between 1991 and 1993. Nelson et al. (1992) guided work in South Australia. Start et al. (1995) was the second edition of Woylie Recovery Plan for the period 1994-2003, written with the expectation that the species could be removed from the threatened species list within a short period of time. Woylies were removed from the Commonwealth and Western Australian threatened species lists in 1996 following an assessment of status (Start et al. 1998). However, from about 2000, Woylies have suffered a significant ongoing decline and they became again the subject of conservation research and management. Woylie conservation was then guided by an interim recovery plan (Freegard 2008). A revised national recovery plan was finalised in 2012 (Yeatman and Groom 2012). This recovery plan, guided by a national Recovery Team, has seven recovery actions:
· Verify the causes of the decline and suppression of recovery and implement remedial action to address these.
· Minimise predation by introduced foxes and cats at priority sites.
· Maintain or improve the health, genetic diversity, relative value and viability of wild populations.
· Maintain genetic diversity of the insurance captive populations at least at 2012 levels.
· Maintain captive population sizes sufficient to act as source populations for future translocations.
· Undertake targeted translocations as re-introductions (and as introductions where necessary) to achieve an enhanced conservation status for the species.
· Inform and educate the community about, and involve the community in, recovery actions.
It is too soon to evaluate progress.
There has been considerable research and management of Woylies in the south-west of Western Australia over a long period of time. Recently, with a serious decline of unknown causes under way, the Western Australian Department of Environment and Conservation initiated a major research program to investigate Woylie decline and that of other ‘critical weight range’ (Burbidge and McKenzie 1989) mammals. The ‘Mesopredator release’ project and ‘Woylie conservation research project’ involved the Invasive Animals Cooperative Research Centre, DEC staff, and people from Murdoch University, Perth Zoo, Australian Wildlife Conservancy, South Australian Department of Environment and Heritage, Australian Wildlife Health Network, Wildlife Disease Association (Australasia), University of Adelaide, Data Analysis Australia, UWA and a number of other professionals and organisations. The major hypotheses examined were that the declines were due to fox predation, cat predation (possibly partly due to mesopredator release), epizootic disease, and/or changes to food resources. Twenty-four university student research projects have also been associated with this research.
The results (Wayne et al. 2011, in press; N. Marlow, P. de Tores and K. Morris et al., pers. comm.) indicated that:
· feral cat predation is currently the most significant cause of Woylie mortality and effective operational cat control for the south-west of Western Australia is urgently required
· the current fox baiting regime is approximately >90% effective in removing foxes from baited reserves despite a high non-target uptake of fox baits by Common Brushtail Possums Trichosurus vulpecula and birds (Australian Ravens Corvus coronoides and Grey Currawongs Strepera versicolor)
· there may be a mesopredator release of feral Cats in the presence of effective fox control in at least some circumstances but mathematical quantification of this phenomenon has not yet been completed
· the Woylie subpopulations in the Upper Warren at least, provide evidence that potentially pathogenic parasites may be associated with the declines and that it is possible disease is making Woylies more vulnerable to predation.
Introductions of Woylies to Katarapko Island on the River Murray floodplain (South Australia) (Katarapko Community Action Group 2001) and to Flinders Ranges National Park (South Australia) (Bellchambers 2000, 2001) both failed due to predation, primarily by introduced Red Foxes and feral Cats.
The Red Fox is controlled via aerial and ground baiting in >30 000 km2 of conservation lands in the south-west of Western Australia. There is ongoing, long-term research aimed at developing operational feral Cat control technology. Conservation lands in the south-west of Western Australia with Woylie subpopulations and the Perup Sanctuary are managed by the Western Australian Department of Environment and Conservation. The South Australian Department of Environment and Natural Resources manages islands in South Australia with Woylie subpopulations. The Australian Wildlife Conservancy manages Karakamia, Yookamurra and Scotia Sanctuaries, plus Mt Gibson Sanctuary (where Woylies will be reintroduced in 2014). Wadderin Sanctuary (430 ha) is managed by a local community group with assistance from Wildlife Research and Management Ltd and the Shire of Narambeen.Captive colonies are housed at Monarto Zoological Park, Hall Gap Zoo, Perth Zoo, Cleland Wildlife Park, Adelaide Zoo, Alice Springs Desert Park (Ford and Hogg 2012) and some zoos in the USA and Europe.
|Citation:||Woinarski, J. & Burbidge, A.A. 2016. Bettongia penicillata. The IUCN Red List of Threatened Species 2016: e.T2785A21961347.Downloaded on 24 September 2018.|
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