|Scientific Name:||Bettongia gaimardi (Desmarest, 1822)|
Kangurus gaimardi Desmarest, 1822
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Burbidge, A.A., Woinarski, J. & Johnson, C.N.|
|Contributor(s):||Johnson, C.N., Johnson, K., Menkhorst, P. & Pauza, M.|
The Eastern Bettong is currently quite widespread and locally abundant in Tasmania, but with a fragmented distribution. It does not meet the criteria for a classification of Vulnerable, but its extent of occurrence is close to the threshold at which it would be considered Vulnerable under criterion B1 if there was also evidence for continuing decline in occurrence, occupancy, habitat quality or abundance. It is therefore possible that increases in predation or declines in habitat quality in the near future could move the species into the Vulnerable category. These changes are possible, given that (i) the feral Cat is widespread in the habitat of the Eastern Bettong, and studies on a closely related species, the Woylie (Marlow et al. 2015) show that increases in the cat population could have major impacts, and (ii) intensification of agriculture in parts of eastern Tasmania could result in increased fragmentation and declines in quality of habitat. Similarly, if the Red Fox were to become established in Tasmania this could be expected to have a major impact on the Eastern Bettong, given the evidence that Red Fox predation caused the extinction of the Eastern Bettong from mainland Australia (Short 1998; Johnson 2006).
|Previously published Red List assessments:|
|Range Description:||The Eastern Bettong formerly occurred throughout much of mainland south-eastern Australia from south-eastern Queensland to south-eastern South Australia, but is now extinct on mainland Australia. It remains widespread in eastern Tasmania from sea level up to 1000 m, however its distribution there is fragmented by land clearing, especially in the midlands of Tasmania. It occurs naturally on Bruny Island (367 km2; Driessen et al. 2010) and was introduced to Maria Island (104 km2) in 1971. Rounsevell et al. (1991) recorded it in 33% of 10 km x 10 km grids in Tasmania, all in the eastern half of the State. In 2011 some Tasmanian Bettongs were brought from Tasmania to establish a captive-breeding colony in Tidbinbilla Nature Reserve, Australian Capital Territory. In May 2012, animals were translocated from this colony to Mulligans Flat Woodland Sanctuary, ACT, a fenced mainland island of c. 400 ha of Yellow Box Eucalyptus melliodora – Blakely’s Red Gum E. blakelyi grassy woodland. This enclosed population has flourished, and it is hoped that it will be possible to use it as a source of animals to be released into nearby unfenced areas subject to control of introduced predators (A. Manning pers. comm. 2015).|
Native:Australia (New South Wales - Regionally Extinct, Queensland - Regionally Extinct, South Australia - Regionally Extinct, Tasmania, Victoria - Regionally Extinct)
|Range Map:||Click here to open the map viewer and explore range.|
In Tasmania, this species is moderately common in suitable habitat but has been affected by past clearing of dry sclerophyll forest and woodland, especially in the midlands of Tasmania. Little of its habitat is protected within reserves and the highest densities occur on private land (DPIPWE 2012). It is sensitive to fragmentation of its habitat. Mammal spotlighting surveys carried out by the Department of Primary Industries, Parks, Water and Environment across Tasmania only detect low numbers of bettongs which have fluctuated widely over the past decade. Recent surveys using camera trapping show that in the midlands bettongs occur only in forest patches larger than approximately 50 ha (R. Gardiner pers. comm. 2015). Abundance has been observed to fluctuate widely within areas of stable habitat, for reasons that are not understood (K. Proft pers. comm. 2015). On the other hand, Tasmanian bettongs sometimes occur at high abundance in plantation forests (M. Pauza pers. comm. 2012). One documented case shows a local population decline in response to increased activity of feral cats (Fancourt 2014), but more extensive surveys have not provided evidence for a general recent impact of cats on abundance (R. Gardiner and R. Hamer pers. comm. 2015).
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
Mainland animals apparently inhabited open forest with a grassy understorey (Seebeck 1995). In Tasmania, the species occurs in eucalypt and casuarina forests and woodlands with grassy or heath ground cover. During the daytime the animals take refuge in nests built under a fallen limb or among short bushes or tussocks, and sited in a shallow depression dug by the animal. The nests are spherical structures with a side entrance. They are well camouflaged and constructed using nesting material collected by the animal, and transported in bundles held in the prehensile tail. The outer wall of the nest is built with coarse grass and twigs, and the resting chamber is given an inner lining of softer grasses or fibres stripped from the bark of stringybark trees. The diet is mainly hypogeal fungi but also includes seeds, tubers and bulbs (Johnson 1994). Home range is 65-135 ha and an individual can travel up to 1.5 km between its nest and feeding areas (Rose and Rose 1998; Rose and Johnson 2008).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||3|
|Movement patterns:||Not a Migrant|
The Eastern Bettong is potentially threatened by predation from the Red Fox (Vulpes vulpes) and feral Cat (Felis catus). Historically, the Red Fox has not occurred in Tasmania, but if it were to become established in Tasmania this could be expected to have a major impact on the Eastern Bettong, given the evidence that predation by the Red Fox caused the species' extinction from mainland Australia (Short 1998; Johnson 2006). There is evidence of a recent incursion of the Red Fox, possibly as a result of a deliberate introduction (Sarre et al. 2013). This triggered an eradication program (http://dpipwe.tas.gov.au/invasive-species/current-programs/fox-eradication-program). There have been no definite records of foxes in Tasmania since 2011 (http://dpipwe.tas.gov.au/invasive-species/current-programs/fox-eradication-program/fox-evidence-update). Analysis of the pattern of fox records through time suggests the population may now be extinct (Caley et al. 2015). The Red Fox remains a potential threat to the Tasmanian Bettong.
Eastern Bettongs are threatened by predation by feral domestic Cats (Fancourt 2014). There is some evidence that the abundance or activity of feral Cats has increased in Tasmania following the decline of the Tasmanian Devil (Sarcophilus harrisii) (Hollings et al. 2013), but the magnitude of this change is still unclear. Recent surveys show that Eastern Bettongs remain abundant in areas where feral cats are present, provided that habitat patches are sufficiently large (R. Gardiner pers. comm. 2015). A very similar species, the Woylie or Brush-tailed Bettong Bettongia penicillata, has recently suffered major declines in south western Western Australia as a result of predation by feral Cats (Marlow et al. 2015). In that case, predation by feral Cats increased following suppression of Red Fox populations by poison baiting, which probably allowed population growth in feral Cats. If the abundance or activity of feral Cats were to increase in a similar way in Tasmania, it is possible that mortality of Eastern Bettongs would increase substantially and populations could decline. It is also possible that feral Cats threaten Eastern Bettongs by transmitting the disease toxoplasmosis, but the evidence from Western Australia suggests that direct predation is likely to be more significant (Marlow et al. 2015).
The sensitivity of the Eastern Bettong to fragmentation of its dry forest and woodland habitat also suggests that further loss of habitat extent could lead to localized extinctions. Possibly, threats from fragmentation (and associated loss of habitat quality) and predation could interact, such that exposure of Eastern Bettongs to feral Cats is higher where habitat has been reduced or degraded, and cats also increase in abundance as a result of disturbances associated with habitat fragmentation. This suggests that even quite small changes in habitat or Cat abundance could be amplified to produce significant population declines.
This species is listed on Appendix I of CITES. It is present in some protected areas. Recommended conservation actions are:
|Citation:||Burbidge, A.A., Woinarski, J. & Johnson, C.N. 2016. Bettongia gaimardi. The IUCN Red List of Threatened Species 2016: e.T2783A21960911.Downloaded on 16 October 2017.|
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