Survey guidelines for Australia’s threatened non-flying mammals

Black-flanked rock wallaby

Petrogale lateralis lateralis

States and territories: Western Australia.

Regions: North-west Cape, Barrow Island, Salisbury Island, Calvert Ranges in the Little Sandy Desert and remnant and reintroduced populations in the wheatbelt (south-west Western Australia) (Eldridge & Pearson 2008).

Habitat: Rock boulders, escarpments and cliff-lines.

Habit: Ground-dwelling.

Avg. body weight: 4500 g (males) and 3500 g (females) (Eldridge & Pearson 2008).

Activity pattern: Nocturnal/partly diurnal.

Diet: Herbivore: grasses, shrubs and forbs.

Breeding: Unknown.

Description

Taxonomy within Petrogale has been investigated over the past decade through a number of morphological, chromosomal and molecular genetic studies (see Eldridge et al. 2001; Campeau-Peloquin et al. 2001 for summaries). It is believed that this genus has undergone recent and rapid radiation (Eldridge & Close 1997). These survey guidelines follow the taxonomy used in Eldridge and Pearson (2008), which recognises:

• 
  P. l. lateralis;
  
• 
  P. l. hacketti;
  
• 
  P. l. pearsoni;
  
• 
  the West Kimberley race; and
  
• 
  the MacDonnell Ranges race.
  

Like all rock wallabies, the black-flanked rock wallaby inhabits areas associated with boulder outcrops and escarpments, and shelters in caves, on rock ledges and among boulders during the day. Shelter sites form an essential part of a rock wallaby’s home range, but animals forage away from their shelter sites during the night (usually at only a short distance, but for many species the distance is unknown). All rock wallabies are herbivores that feed on grasses, forbs and shrubs (Eldridge & Pearson 2008).

Survey methods

On the basis of previous surveys, the following survey techniques are recommended to detect the presence of the black-flanked rock wallaby in areas up to 5 hectares in size:

• 
  daytime searches for potentially suitable habitat resources, such as shelter sites (caves, rock boulders and rock ledges) in suitable boulder pile, escarpment and cliff-line habitats (description of the survey technique and recommended effort is outlined in Section 3.3.11)
  
• 
  daytime searches for signs of activity, including tracks, scats and rock shelters worn smooth from resting (description of the survey technique and recommended effort is outlined in Section 3.3.11). However, where the black-flanked rock wallaby occurs in sympatry with Rothschild's rock wallaby, Petrogale rothschildi (Hamersley range region of Western Australia), scats may need to be collected and analysed using either genetic techniques to distinguish between species. Scats should be collected from across the entire area from searches conducted during the day. For example, the technique used by Alacs and colleagues (2003) for analysis of quokka scats was collection of fresh pellets (less than one day old) which were then frozen at –20 degrees celsius until DNA extraction. However, further advice should be sought from an expert regarding the collection process, prior to the commencement of any field work
  

• 
  possibly the collection of predator scats, owl casts or remains, targeting predatory bird and mammal nests and dens (description of the survey technique and recommended effort is outlined in Section 3.2.3)
  

• 
  use of baited camera traps (description of the survey technique and recommended effort is outlined in Section 3.3.6)
  
• 
  observations for rock wallabies basking during the day, or becoming active at dusk, using binoculars from a location on the ground beneath suitable habitat or possibly from a helicopter according to a suggested survey technique and effort provided in Section 3.3.11 (heeding caution to minimise disturbance to animals to ensure wallabies do not fall).
  

The taxonomy of P. lateralis, like some other rock wallaby species, is not completely resolved. However, the known distribution of P. lateralis (see Eldridge & Pearson 2008) does not overlap with other species, with the exception of a possible overlap between P. l. lateralis and P. rothschildi in the Hamersley Range region of Western Australia. As all P. lateralis subspecies are listed on the EPBC Act (1999), surveys designed to detect the presence of P. lateralis from a subject site need not conduct cage trapping surveys. Survey effort instead should focus on detecting signs in suitable habitat. Should confirmation of the species identity be required, then cage trapping surveys (conducted according to the description and recommended survey effort provided in Section 3.3.10 and 3.3.11) or genetic analysis of hair or tissue samples may need to be considered. These survey techniques can only be conducted with appropriate permission and licensing from relevant state or territory government organisations.

Similar species in range

The known distribution of P. lateralis (see Eldridge & Pearson 2008) does not overlap with other species, with the exception of possible overlap between P. l. lateralis and P. rothschildi in the Hamersley Range region of Western Australia. Petrogale rothschildi is distinguished from P. l. lateralis by its shorter and uniformly brown ears, absence of a side-stripe and occasional purple colouration around the shoulders (Pearson & Eldridge 2008).

References

Campeau-Peloquin, A., Kirsch, J.A.W., Eldridge, M.D.B. and Lapointe, F. 2001. Phylogeny of the rock-wallabies, Petrogale (Marsupialia: Macropodidae), based on DNA/DNA hybridisation. Australian Journal of Zoology 49: 463-486.

Eldridge, M.D.B. and Pearson. D.J. 2008. Black-footed Rock wallaby Petrogale lateralis. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan) pp. 376-380 (Reed New Holland: Sydney).
Eldridge, M.D.B. and Close, R.L. 1997. Chromosome and evolution in rock-wallabies Petrogale (Marsupialia: Macropodidae). Australian Mammalogy 19: 123-135.
Eldridge, M.D.B., Wilson, A.C.C., Metcalfe, C.J., Dollin, A.E., Bell, J.N., Johnson, P.M., Johnston, P.G. and Close, R.L. 2001. Taxonomy of rock-wallabies, Petrogale (Marsupialia: Macropodidae). III. Molecular data confirms the species status of the purple-necked rock wallaby (Petrogale purpureicollis Le Souef). Australian Journal of Zoology 49: 323-343.
Pearson, D.J. and Eldridge, M.D.B. 2008. Rothschild's Rock wallaby. Petrogale rothschildi. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan) pp. 389-390 (Reed New Holland: Sydney).