THREATENED SPECIES SCIENTIFIC COMMITTEE Established under the Environment Protection and Biodiversity Conservation Act 1999 The Minister deleted this species from the Vulnerable category effective from 22 Feburary 2019 Listing Advice Mesembriomys macrurus Golden-backed Tree-rat Taxonomy Conventionally accepted as Mesembriomys macrurus (Peters, 1876). No subspecies are recognised. Summary of assessment Conservation status The Golden-backed Tree-rat was listed as Vulnerable effective July 2000. The assessment has determined that the species is no longer eligible for inclusion in any category of the list and is eligible for delisting. Species can be listed as threatened under state and territory legislation. For information on the listing status of this species under relevant state or territory legislation, see http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl Reason for conservation assessment by the Threatened Species Scientific Committee The Golden-backed Tree-rat was listed as Vulnerable under the predecessor to the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act) the Endangered Species Protection Act 1992 and transferred to the EPBC Act in July 2000. This advice follows assessment of new information provided to the Committee to change the listing status of the Golden-backed Tree-rat. Public Consultation Notice of the proposed amendment and a consultation document was made available for public comment for 30 business days between 20 April 2018 and 1 June 2018. Any comments received that were relevant to the survival of the species were considered by the Committee as part of the assessment process. Species information Description The Golden-backed Tree-rat is a large rodent weighing 207−330 g, with a head and body length of 188−245 mm and a tail length of 291−360 mm (McKenzie & Kerle 2008). It is midway in size between two other large semi-arboreal species in northern Australia, the smaller Conilurus penicillatus (Brush-tailed Rabbit-rat) and the larger Mesembriomys gouldii (Black-footed Tree-rat). Its fur is grey above and on the sides, and creamy white below. The feet are white. The basal third of the long tail is grey while the remainder is white; the terminal third has a white brush. A distinctive mid-dorsal stripe of orange-brown fur, which stretches along the back of the crown to the base of the tail, distinguishes it from all other tree-rats (McKenzie & Kerle 2008). Mesembriomys macrurus (Golden-backed Tree-rat) Listing Advice Page 1 of 17 Indigenous names include Koorrawal, Wunggangbarn or Jari (Jaradada et al. 2011) and Jarri Manya (Cheinmora et al. 2017). Distribution The Golden-backed Tree-rat has been recorded from the top end of the Northern Territory (NT), and the Kimberley and Pilbara in Western Australia (WA). It has undergone a substantial historical range contraction and appears to have disappeared from the NT, the Pilbara and the south-west Kimberley (Palmer et al. 2003). Historical In the Northern Territory it has been recorded at three sites: ‘Balanbrinni’ (probably Balbarini) in the upper McArthur in 1901; Nellie Creek (in the upper Mary River) in 1903; and Deaf Adder Gorge in 1969 (Parker 1973). It has not been confirmed anywhere else in the Northern Territory despite many surveys across much of the Top End of the Northern Territory over the last 40 years (Woinarski et al. 2012). A review of Indigenous knowledge across the Top End has suggested that the final phase of its decline in the NT was very recent, with plausible records between the late 2000s and early 2010s (Ziembicki et al. 2013). However, there is a small possibility that it may still exist in the Northern Territory, as surveys have not been extensive or intensive, and the species is difficult to detect as it occurs in thick and complex habitat in remote and difficult to access areas (DENR 2018. pers comm 3 May). In Western Australia, subfossil records from Cape Range show that it once had a Pilbara distribution (Baynes & McDowell 2011), with the type specimen originating from near Roebourne in 1875 (McKenzie & Kerle 2008). However, since 1903 all known records have come from the higher rainfall areas of the north-west Kimberley, and the species has disappeared from the Pilbara (McKenzie & Kerle 2008) and drier parts of the Kimberley (McKenzie 1981a). Current The current distribution of the Golden-backed Tree-rat is restricted to the north-west Kimberley (Start et al. 2012), from near Kalumburu in the north to Yampi Peninsula in the south (e.g. Kitchener et al. 1981), including several Kimberley islands in the Buccaneer Archipelago (DPaW 2012). The species occurs in the Mitchell Plateau, Prince Regent National Park, Artesian Range and Yampi Peninsula. It has also been recorded more recently from a number of locations in pockets of suitable gorge country in the King Leopold Ranges, more than 100 km inland in the central Kimberley (I Radford, unpublished data; Corey & Radford 2017). It has been recorded on 11 islands: Augustus, Carlia, Chambers, Conilurus, Hidden, Jar, Lachlan, an unnamed island in Scott Strait, Uwins, Wollaston and Buckle Head (Burbidge & Abbott 2017; Legge et al. 2018; A Burbidge 2018. pers comm 1 August). Prince Regent National Park (including part of Bachsten Creek) is managed by the WA Department of Biodiversity, Conservation and Attractions. The remaining land on which the species occurs is largely managed by Indigenous peoples: • Mitchell River National Park and Lawley River National Park − native title areas managed by the Wunambal Gaambera Aboriginal Corporation (WGAC); • Uunguu Indigenous Protected Area (IPA), Mitchell Plateau – on the national reserve system, managed by WGAC; • Wilinggin IPA, including part of Bachsten Creek (e.g. Bachsten Camp) – managed by the Wilinggin Aboriginal Corporation (WAC); • Dambimangari IPA − on the national reserve system, managed by the Dambimangari Aboriginal Corporation (DAC); • Kimberley Islands – part of the IPAs or native title management by Mayala, Dambimangari and Uunguu; Mesembriomys macrurus (Golden-backed Tree-rat) Listing Advice Page 2 of 17 • Charnley River station, including part of the Artesian Range (Charnley-Artesian Range Wildlife Sanctuary) – a pastoral lease managed by the Australian Wildlife Conservancy (AWC), with native title interests (WAC); • Yampi Sound Training Area – Australian Government Defence Land and Aboriginal Reserve. The AWC has an agreement with the Department of Defence and a partnership with DAC to manage the land. (T Vigilante 2018. pers comm 24 April & 3 August; AWC 2018. pers comm 31 May; K Mitchell 2018. pers comm 3 August). Cultural significance The tails of the Golden-backed Tree-rat were traditionally used to make special necklaces by the Indigenous people of Wunambal Gaambera Country in the north-west Kimberley (Karadada et al. 2011, p. 98). Relevant biology/ecology In its current range the Golden-backed Tree-rat occurs in a variety of highland and lowland habitats, including rainforest and riparian areas (on volcanic, lateritic, sandstone and floodplain surfaces), eucalypt-dominated woodlands and savannas (particularly with fruiting trees and shrubs), Livistona palm woodlands, and rugged sandstone plateaux and screes (Woinarski et al. 2014; AWC 2018. pers comm 31 May). Other geological associations include rolling quartzite hills, granite hills, and lowland plains adjacent to hills and escarpments (AWC 2018. pers comm 31 May). In savannas it is more abundant in high rainfall rocky areas (Radford et al. 2014). The species is largely nocturnal, but individuals have been seen foraging shortly before dusk and soon after sunrise (Woinarski et al. 2014; Hohnen et al. 2015). In thick vegetation and near vertical rock faces, it is mainly arboreal (on trees or rocks) but spends time on the ground. The species can quickly move long distances, often through dense grass, scampering along with its tail held high. In sparser vegetation and rocky areas, it spends most of its time on the ground (Woinarski et al. 2014). The Indigenous Kwini people of the far-north Kimberley observed that it “[ran] around trees and hunt[ed] on the ground” (Cheinmora et al. 2017, p. 170). It has been observed denning in tree hollows, in rock scree, and on cliffs, or occasionally in loose woven nests under the spiky crown of pandanus (McKenzie & Kerle 2008; Hohnen et al. 2015). The species utilises the edge of rainforest patches for foraging, feeding in both the rainforest and adjacent eucalypt woodland (Woinarski et al. 2014). The home ranges of animals in the Artesian Range are on average 6.3 ha, varying between 0.24 and 30.44 ha (Hohnen et al. 2015). Individuals are known to travel over 1 km from their refuge into open savanna to forage at night (Hohnen et al. 2015). Flowers, fruits and termites have been recorded as the main dry- season foods, but grasses, ants and beetles are occasionally eaten (Morton 1991). Pregnant females and juveniles have been recorded in August, October and November, suggesting a mid- to late- dry season breeding period. The litter size is usually two, but one and three have been recorded (McKenzie & Kerle 2008). Longevity in captivity is 7 years (Weigl 1971, in AnAge 2012). Generation time is here assumed to be around 3 years. In the wet-dry tropics, climatic variability (particularly rainfall), through its influence on food supply, may strongly influence demographic changes in populations and give rise to opportunistic breeding in some species (Bolton et al. 1982, Kerle & Burgman 1984, Friend 1987a). Populations of the Black-footed Tree-rat in the wet-dry tropics of the Northern Territory markedly increased in size following a high rainfall event in 1981, and declined following lack of rain in 1983 (Taylor & Tullock 1985; Friend 1987b). However, in an analysis of data from eight mammal surveys from 1994 to 2011, Radford et al. (2014) found no evidence of order of magnitude changes in the abundance of mammal species (including the Golden-backed Tree- rat) in tropical savannas of the Kimberley due to annual changes in rainfall.