Survey guidelines for Australia’s threatened non-flying mammals

Carpentarian rock rat

Zyzomys palatalis

States and territories: Northern Territory (may range into Queensland but currently there are no confirmed records [Puckey et al. 2003]).

Regions: Known only from five sandstone gorges and escarpments in one pastoral lease (Wollogorang Station) near the Northern Territory-Queensland border, within 30 km of the original capture site (Puckey et al. 2008).

Habitat: Dry rainforest thickets that fringe escarpments of deep gorges and scree slopes. Plant species characteristic of this habitat include pouteria Pouteria sericea, nutwood Terminalia subacroptera, rosewood T. volucris, common celtis Celtis phillipensis, rock fig Ficus leucotricha, white fig F. virens, the vine Cissus reniformis, gray nickabean Caesalpinia bonduc and the helicopter tree Gyrocarpus americanus (Trainor et al. 2000).

Habit: Ground-dwelling (possibly shelters in rock crevices).

Avg. body weight: 115 g (Puckey et al. 2008).

Activity pattern: Nocturnal.

Diet: Fruits and seeds of fleshy-fruited plants.

Breeding: Females generally give birth to between one and three young per litter and those living into their second year are capable of producing up to four litters, with breeding probably occurring in most months (Trainor 1996).

Description

The Carpentarian rock rat is one of five species of Zyzomys which inhabit rocky regions of Australia. It was first described in 1987 from a single female collected near Banyan Gorge on Wollongorang Station. Today there are only five known localities where the Carpentarian rock rat has been recorded, all within a 35 km radius of the original specimen (Trainor et al. 2000; Puckey et al. 2008). The preferred habitat is monsoon forest occurring on rocky slopes with sandy gorges (Churchill 1996). More recently radio-telemetry studies suggest the species prefers the valley and slope habitats rather than the plateau, with adults preferring slope habitats while juveniles prefer the valley habitat (Puckey et al. 2004). The majority of the species’ diet is made up of rainforest fruits including native figs Ficus species, billygoat plum Terminalia carpentariae, emu apple Owenia vernicosa and river pandanus Pandanus aquaticus (Puckey et al. 2003).

Survey methods

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

• 
  daytime searches for potentially suitable habitat resources such as rock and boulder outcrops, escarpments, gorges and cliffs with associated monsoon rainforest (description of the survey technique and recommended effort is provided in Section 3.1)
  
• 
  daytime searches for signs such as scats or tracks in sandy substrates surrounding rocks or in caves and overhangs (description of the survey technique and recommended effort is provided in Section 3.2)
  
• 
  collection of predator scats, owl casts or remains in predatory bird/mammal nests/dens (description of the survey technique and recommended effort is provided in Section 3.2)
  
• 
  hair sampling device surveys using a mixture of peanut butter, rolled oats and honey or sultanas conducted according to the technique and recommended effort outlined in section 3.3.7
  
• 
  Elliott A trapping surveys conducted according to the technique and recommended effort provided in Section 3.3.9. However, Zyzomys species are particularly susceptible to tail stripping when trapped, and should be handled with care to avoid this occurring
  
• 
  consultation with local people, including leaseholders, station hands, park rangers and field workers and investigating potential Indigenous knowledge of this species’ presence in an area. Consultation is particularly important for this species as it may be present at very low densities for extended periods of time during dry conditions, making it virtually impossible to detect under such conditions
  
• 
  placement of baited camera traps (same as for predator pads) in suitable habitat, which could be conducted in conjunction with hair tubes in remote locations accessed by helicopters (description of the technique is outlined in Section 3.3.6)
  
• 
  searching for the remains of chewed fruit in crevices, under boulders and in overhangs
  
• 
  possibly spotlight surveys conducted according to the technique description and recommended effort provided in Section 3.3.3.
  

Similar species in range

The Carpentarian rock rat is sympatric with the common rock rat Zyzomys argurus. The two species can be distinguished by the smaller size of the common rock rat (average 45 grams) and its naked tail, compared to the furred tail of the Carpentarian rock rat, which is darker on the upper surface of the tail and has longer hair towards the tip (Menkhorst & Knight 2004).

References

Churchill, S.K. 1996. Distribution, habitat and status of the Carpentarian Rock-rat, Zyzomys palatalis. Wildlife Research 23: 77-91.

Menkhorst, P. and Knight, F. 2004. A field Guide to the Mammals of Australia. Second Edition. (Oxford University Press: Melbourne).
Puckey, H., Woinarski, J. and Trainor, C. 2003. "Revised recovery plan for the Carpentarian Rock Rat (Zyzomys palatalis)". Parks and Wildlife Commission of the Northern Territory.
Puckey, H., Lewis, M., Hooper, D. and Mitchell, C. 2004. Home range, movement and habitat utilisation of the Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch. Wildlife Research, 31: 327-337.
Puckey, H., Palmer, C., Woinarski, J.C.Z. and Churchill, S.K. 2008. Carpentarian Rock-rat Zyzomys palatalis. In ‘The Mammals of Australia’ (Eds. S. Van Dyck and R. Strahan) pp. 656-658. (Reed New Holland: Sydney).
Trainor, C. 1996. Carpentarian Rock Rat (Zyzomys palatalis): survey to classify species status. Report to Australian Nature Conservation Agency, Canberra.
Trainor, C., Fisher, A., Woinarski, J. and Churchill, S. 2000. Multiscale patterns of habitat use by the Carpentarian rock-rat (Zyzomys palatis) and the common rock-rat (Z. argurus). Wildlife Research 27: 319-332.