Onychogalea fraenata 

Scope: Global

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Diprotodontia Macropodidae

Scientific Name: Onychogalea fraenata
Species Authority: (Gould, 1841)
Common Name(s):
English Bridled Nailtail Wallaby, Merrin, Bridled Wallaby, Bridled Nail-tailed Wallaby
French Onychogale vridé
Spanish Canguro Rabipelado Oriental

Assessment Information [top]

Red List Category & Criteria: Vulnerable D1+2 ver 3.1
Year Published: 2016
Date Assessed: 2016-03-01
Assessor(s): Burbidge, A.A., Johnson, C.N. & Zichy-Woinarski, J.
Reviewer(s): Hawkins, C.
Contributor(s): Augusteyn, J., Fisher, D., Horsup, A. & Murphy, D.
The species is listed as Vulnerable because of its small total population size (D1) and restricted number of locations (D2). As a result it is prone to the effects of human activities or stochastic effects, such that it could become Critically Endangered or even Extinct within a short time period. However, over the last 10 years there have been no declines in abundance or occupancy of sufficient magnitude to justify listing as Endangered.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The Bridled Nailtail Wallaby was formerly spread over a large area that extended through inland regions of eastern Australia from south western South Australia to as far north as the base of Cape York Peninsula. The species declined catastrophically during the nineteenth and early twentieth centuries, and by 1937 it was thought to be extinct. In 1973 an isolated population was discovered near the town of Dingo in central Queensland, on a property now protected as Taunton National Park (Scientific). Reintroduced populations have been established from source animals at Taunton in three sites: two unfenced populations at Idalia National Park and Avocet National Reserve in central Queensland, and a third population in a fenced reserve at Scotia Sanctuary in New South Wales. The area of occupancy of each of the four subpopulations is 2 km2 (Avocet), 4 km2 (Taunton), 80 km2 (Idalia) and 80 km2 (Scotia) (D. Fisher pers. comm. 2014).
Countries occurrence:
Australia (Queensland)
Additional data:
Estimated area of occupancy (AOO) - km2:166Continuing decline in area of occupancy (AOO):No
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:166-20000
Continuing decline in extent of occurrence (EOO):No
Number of Locations:4Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Although the Bridled Nailtail Wallaby was reported to be a common animal at the time of European settlement (Lundie-Jenkins and Lowry 2005), its decline was rapid. The current total population size at unfenced sites is small. Recent (2011-2012) estimates of population size based on mark-recapture and transect counting are approximately 90-130 individuals at Taunton and 100 individuals at Idalia (J. Augusteyn pers. comm. 2014; A. Horsup pers. comm. 2014, D. Fisher pers. comm. 2014). Estimates using similar methods at Avocet were 30-40 in 2008 (Kinglsey et al. 2012) and 66 in 2012 (A. Horsup pers. comm. 2014, D. Fisher pers. comm. 2014). The area of occupancy at Taunton has declined considerably, from approximately 25 km2 in the late 1908s to 4 km2 currently (Wang and Fisher 2012). In 1985 the population at Taunton was estimated to be approximately 500 (Tierney 1985), and in 1991 was thought to be approximately 1400 (Davidson 1991) though this might have been an overestimate (D. Fisher pers. comm. 2014). The size of the Idalia population has fluctuated considerably. It was established in 1993 from a release of 275 individuals (Lundie-Jenkins and Lowry 2005), increased to approximately 400 individuals by 1999 (Pople et al. 2001), then declined as a result of drought in 2002. In 2008 and 2011 the known minimum population size was 123 and 96 respectively (J. Augusteyn pers. comm. 2014).

The population in the Australian Wildlife Conservancy's Scotia Sanctuary, where a fence excludes non-native predators, is the largest, consisting of approximately 2000 free-ranging animals, with a further 1500 in a captive breeding program (S. Legge pers. comm. 2014). The free-ranging animals are included in the overall population estimate as they are considered to be a viable and self-sustaining population established for more than five years. The Scotia population was established from 12 animals translocated in 1998, followed by further releases of 162 individuals in 2004-05.
Current Population Trend:Stable
Additional data:
Number of mature individuals:800-1100
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:In the past, this species inhabited a wide range of vegetation types, generally characterized as dry woodlands, thickets and grassland. In its current limited distribution it shows a preference for transitional vegetation between dense Acacia scrub and eucalyptus open woodlands with grassy understory, and between pasture and young regrowth of Brigalow Acacia harpophylla (Evans 1992). It forages solitarily, mostly under tree cover, unless its food is scarce in dry times when it ventures further into open areas (Fisher 2000). It feeds at night, and shelters during the day in scrapes in dense thickets or in hollow logs (Fisher 2000). Young that have left the pouch but are still suckling remain hidden under low shrubs, in dense grass or in logs for most of the day and night. Dense ground cover is therefore essential for survival of juveniles (Fisher and Goldizen 2001).

Bridled Nailtail Wallabies feed on a high diversity of plants (> 60 species) and show strong selection for plant species and plant parts of high nutritional quality and low fibre content. They feed on forbs, grasses and browse, in proportions that vary according to availability in different seasons. Forbs are generally selected for, and grasses selected against, especially during dry seasons when the diet also includes woody browse species (Evans and Jarman 1998).They can breed at any time of year, and in good conditions females may raise up to three young in a year (Lundie-Jenkins and Lowry 2005).
Generation Length (years):2.6

Threats [top]

Major Threat(s): The species is threatened by introduced predators, the Red Fox and feral Cat especially; Dingoes or wild Dogs may also threaten small surviving population in unfenced sites. The impact of foxes is attested by the fact that the last surviving wild population (at Taunton) occupied a site at which foxes were absent. Populations introduced into a large fenced reserve at Scotia from which foxes and cats are excluded increased rapidly to high numbers, but subpopulations released outside those fences collapsed in the presence of low densities of foxes (S. Legge pers. comm. 2014). Modelling of the Taunton population demonstrated that predation of juveniles by feral Cats was sufficient to cause decline (Fisher et al. 2000). Wild Dogs also appear to be a significant cause of mortality in that population (J. Augusteyn pers. comm. 2014). Other threats include destruction of habitat, which probably contributed to historical declines, and degradation of habitat through invasion of introduced plants, especially Buffel Grass Cenchrus ciliaris. Drought is a cause of stochastic variation in population size, which could be critical for the three populations that have populations numbering in the hundreds or less.

Conservation Actions [top]

Conservation Actions: The Bridled Nailtail Wallaby is listed a threatened species under Australian law. It is currently known only from protected areas. A recovery plan has been developed (Lundie-Jenkins and Lowry 2005). It is listed on CITES Appendix I.

Recommendations from the recovery plan (Lundie-Jenkins and Lowry 2005), include: managing existing Bridled Nailtail Wallaby populations to maintain or increase current population levels; translocation of Bridled Nailtail Wallabies to areas of suitable habitat, and monitoring existing and future translocated populations; maintaining captive breeding and sanctuary populations; community extension and education. Most of these actions have been implemented, resulting in stabilization of populations or reduction in rate of population decline at some sites.

The locations of all three wild unfenced populations are managed for predators, fire and weeds, and there is management of predators and fire at the one free-ranging fenced population. Research on the impacts of Buffel Grass on wallaby habitat and its control is underway. Captive populations are maintained to provide animals for reintroduction and research; these are at the University of Queensland (Gatton); Kial, a private wildlife care facility; and the Western Plains Zoo in New South Wales.

Citation: Burbidge, A.A., Johnson, C.N. & Zichy-Woinarski, J. 2016. Onychogalea fraenata. The IUCN Red List of Threatened Species 2016: e.T15330A21958130. . Downloaded on 30 July 2016.
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