Survey guidelines for Australia’s threatened non-flying mammals

Golden bandicoot (Barrow Island)

Isoodon auratus barrowensis

States and territories: Western Australia.

Regions: Barrow Island, Middle Island and Augustus Island off Western Australia (DEWHA 2008).

Habitat: Hummock grass and limestone caves.

Habit: Ground-dwelling.

Avg. body weight: 310 g (McKenzie et al. 2008).

Activity pattern: Nocturnal.

Diet: Omnivore: insects and tubers.

Breeding: Breeding occurs throughout the year, usually after rain (McKenzie et al. 2008).

Description

The golden bandicoot had a former distribution that covered much of mainland Australia (McKenzie et al. 2008). Today, the species range is greatly restricted, with three subspecies occurring as follows:

• 
  I. a. auratus on Marchinbar Island (Northern Territory), the northern Kimberley (mainland Western Australia) and Augustus Island (Western Australia)
  
• 
  I. a. barrowensis on Barrow Island and Middle Island off the Pilbara coast (Western Australia) (Woinarski 2001), and
  
• 
  I. a. arnhemensis, previously recorded in Arnhem Land (McKenzie et al. 2008), but which has not been recorded from definite observations on the Northern Territory mainland in recent years despite large-scale biodiversity surveys (Woinarski 2001).
  

The taxonomy of these subspecies is currently under review and relationships between this species and the southern brown bandicoot I. obesulus are being explored (Pope et al. 2001).

The Barrow Island golden bandicoot is a relatively small subspecies of the Isoodon auratus complex, confined to Barrow Island and Middle Island off the Pilbara coast in Western Australia (McKenzie et al. 2008). On those islands the species is relatively abundant (McKenzie et al. 2008). Golden bandicoots on Barrow Island have a similar diet to the ones on Marchinbar Island, feeding on ants, termites, turtle eggs, small reptiles and the common rock rat Zyzomys argurus (McKenzie et al. 2008).

Survey methods

On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the golden bandicoot in areas up to 5 hectares in size:

• 
  daytime searches for potentially suitable habitat resources, such heath and open woodland habitats on sandy or sandstone substrates (description of the survey technique and recommended effort is outlined in Section 3.1)
  
• 
  daytime searches for signs of activity, including tracks, scats, nests and conical foraging holes (description of the survey technique and recommended effort is outlined in Section 3.2)
  
• 
  collection of predator scats, owl casts or remains, targeting predatory bird/mammal nests/dens (description of the survey technique and recommended effort is outlined in Section 3.2)
  

• 
  soil plot surveys conducted according to the description of the technique and the recommended effort provided in Section 3.3.2
  

• 
  spotlight surveys conducted according to the description of the technique and the recommended effort provided in Section 3.3.3
  
• 
  baited camera traps using universal bait (description of the survey technique and recommended effort is outlined in section 3.3.6).
  

Southgate and colleagues (1996) reported that female bandicoots rejected pouch young after handling. Given that established non-invasive techniques like camera trapping are available, these options should be fully explored before using more invasive techniques. If animals are to be caught, high-sugar bait (containing honey or golden syrup) should be used in traps (see Southgate et al. 1996).

Hair sampling device surveys are not recommended because Southgate and colleagues (1996) did not successfully detect the golden bandicoot on Marchinbar Island with this technique. The geographic distribution of this species and its subspecies is still not well known and this should be considered when undertaking field surveys.

Similar species in range

The golden bandicoot on Barrow Island and Middle Island does not overlap in distribution with other bandicoot species.

References

DEWHA 2008. Approved Conservation Advice for Isoodon auratus barrowensis (Golden Bandicoot - Barrow Island). A statement for the purposes of approved conservation advice (s266B of the Environment Protection and Biodiversity Conservation Act 1999), approved the Minister / Delegate of the Minister on: 26/3/2008. Commonwealth Department of the Environment, Water, Heritage and the Arts.

McKenzie, N.L., Morris, K.D. and Dickman, C.R. 2008. Golden Bandicoot, Isoodon auratus. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan) pp. 178-180 (Reed New Holland: Sydney).
Southgate, R., Palmer, C., Adams, M., Masters, P., Triggs, B. and Woinarski, J. 1996. Population and habitat characteristics of the Golden Bandicoot (Isoodon auratus) on Marchinbar Island, Northern Territory. Wildlife Research 23: 647-664.

Golden-backed tree rat

Mesembriomys macrurus

States and territories: Western Australia and possibly Northern Territory.

Regions: Currently confined to the North Kimberley region and islands in the Buccaneer Arch group where the average annual rainfall is above 600 mm (Palmer et al. 2003; McKenzie & Kerle 2008). Its current status in the Top End of the Northern Territory is poorly understood with unconfirmed sightings and possible hair samples from the Wessel Islands and Indigenous knowledge indicating the persistence of at least one population on the Arnhem Land plateau (Woinarski & Palmer 2006). The species formerly occurred in Western Australia as far south as Cape Range near Exmouth, including the Pilbara coastline and in the Top End of the Northern Territory; including Deaf Adder Creek in western Arnhem Land (Parker 1973; Watts & Aslin 1981).

Habitat: In the Kimberley the species occurs in a variety of habitats, including rainforest, eucalypt-dominated woodlands, lateritic uplands with Livistonia palms, blacksoil plains with Pandanus trees, sandstone screes, mangrove swamps and coastal beaches adjoining the above habitats (McKenzie & Kerle 2008). The last specimen collected in the Northern Territory (1969) came from Pandanus along a watercourse in sandstone habitat in Deaf Adder Creek. It has also been recorded in hollow trees of Eucalyptus scrubs in the Roebuck Bay area of the south-western Kimberley’s (Dahl 1897).

Habit: Mostly arboreal.

Avg. body weight: 267 g (McKenzie & Kerle 2008).

Activity pattern: Nocturnal, possibly crepuscular.

Diet: Omnivorous, eating flowers, fruits, insects, plant shoots, grasses and leaves (McKenzie & Kerle 2008). Its diet in formerly occupied drier habitats is unknown, although it was recorded raiding dwellings for rice and flour in the Broome region (McKenzie & Kerle 2008).

Breeding: Litters of one to three, possibly breeds throughout the year (Menkhorst & Knight 2004).

Description

The golden-backed tree rat is a large rodent that has a distinctive long, slightly brush-tipped tail and a broad chestnut-gold stripe along the back. The species’ former range encompassed much of the Pilbara and Kimberley regions of Western Australia and the northern part of the Northern Territory. The range has contracted, with the species now presumed locally extinct in the Pilbara and restricted to the higher rainfall areas of the northern Kimberleys, including five offshore islands in the Buccaneer Arch group (McKenzie & Kerle 2008). The species’ status in the Northern Territory currently remains unclear, with no positive sightings recorded since 1969, although the species has been detected in hair samples collected from the Wessel Islands in 1993 (Woinarski 2000).

No single process has been identified as contributing to the decline of the species’ range, although introduced predators and changed fire regimes resulting in broad-scale habitat alteration are likely to have been significant (Woinarski 2002).

Survey methods

There is currently not enough information available to formulate general survey methods required to detect the golden-backed tree rat. The survey methods suggested here conform to the Northern Territory DIPE (2005) standard biodiversity survey methods (see Appendix). The following survey techniques are recommended to detect the presence of the golden-backed tree rat in areas up to 5 hectares in size:

• 
  daytime searches for potential habitat resources, such as Pandanus trees (habitat preferences are described in Section 3.2.9)
  
• 
  daytime searches for signs of activity, such as nests in trees, particularly in Pandanus, scratches on tree trunks or scats (description of the survey technique and recommended effort is outlined in Section 3.2)
  
• 
  stagwatching surveys at potential nest sites (description of the survey technique and recommended effort is outlined in Section 3.3.4)
  
• 
  spotlight surveys conducted according to Section 3.3.3 along transects, tracks or roads (additional surveys from a vehicle may also be made)
  
• 
  combined arboreal and ground-based Elliott B and cage trapping surveys (divide the effort recommended for both surveys in half and carry them out simultaneously) across the subject site according to a stratified design as described in Section 3.3.9
  
• 
  camera traps (including untimed systems) may be a useful technique using bait stations of peanut butter and rolled oats (M Schulz pers. obs.).
  

Similar species in range

The golden-backed tree rat is sympatric with the closely related black-footed tree rat, Mesembriomys gouldii. The latter species is larger, with a black tail and black feet. In contrast, the golden-backed tree rat has pink feet, a white tail, and a distinct golden-chestnut dorsal stripe that distinguishes it from all other tree rats.

References

Dahl, K. 1897. Biological notes on north-Australian mammalia. Zoologist 1: 189 – 216.

Davis, 2009. Personal communication regarding the Golden-back Tree Rat.
McKenzie, N.L. and J.A. Kerle 2008. Golden-backed tree rat Mesembriomys macrurus. In The Mammals of Australia, Third Edition ‘(Eds. Van Dyck, S. and R. Strahan) pp. 593-595 (Reed New Holland: Sydney).
Menkhorst, P. and Knight, F 2004. A Field Guide to the Mammals of Australia. Second Edition. (Oxford University Press: Melbourne, Australia).
NT DIPE 2005. Guidelines for the Biodiversity Component of Environmental Impact Assessment. Prepared by the Biodiversity Conservation Division, for the Northern Territory Department of Infrastructure Planning & Environment.
Palmer, C., Taylor, R. and Burbidge, A. 2003. Recovery plan for the Golden Bandicoot Isoodon auratus and Golden-backed tree rat Mesembriomys macrurus 2004-2009. Northern Territory Department of Infrastructure Planning and Environment, Darwin.
Parker, S.A. 1973. An annotated checklist of the native land mammals of the Northern Territory. Records of the South Australian Museum 16: No. 11.
Watts, C.H.S. and Aslin, H.J. 1981. The Rodents of Australia. (Angus & Robertson: Sydney).
Woinarski, J.C.Z. 2000. The conservation status of rodents in the monsoonal tropics of the Northern Territory. Wildlife Research 27: 421-435.
Woinarski, J.C.Z. 2002. "Golden-backed Tree Rat Mesembriomys macrurus". Threatened species information sheet, Northern Territory Department of Infrastructure, Planning and Environment.
Woinarski, J. and Palmer, C. 2006. Golden-backed tree rat Mesembriomys macrurus. Threatened species of the Northern Territory. Parks and Wildlife Commission, Darwin.