#Threatenedspecies of the Week: Petrogale lateralis lateralis (Black-flanked Rock-wallaby)

Black-flanked rock-wallaby. © Phil Lewis & Mike Griffiths / WWF-Aus
Black-flanked rock-wallaby. © Phil Lewis & Mike Griffiths / WWF-Aus

To celebrate the twenty-three wallabies that were moved from the Wheatbelt to Kalbarri National Park this week – to boost the tiny population of the threatened species – this weeks #threatenedspecies is the Petrogale lateralis lateralis (Black-flanked Rock-wallaby).

Petrogale lateralis lateralis (Black-flanked Rock-wallaby) is listed as Vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and listed as ‘Schedule 1 – Fauna that is rare or is likely to become extinct under the Western Australian Wildlife Conservation Act 1950.  

The main known and perceived conservation threats facing the Black-flanked Rock-wallaby are predation by foxes, feral cats and dogs; competition for food and shelter from introduced herbivores; changes to fire regimes since colonisation; habitat destruction from clearing, mining and quarrying; habitat degradation due to weed incursions; small population sizes and population fragmentation; disease; disturbance by tourists; and drought and the effects of climate change.

The Black-flanked Rock-wallaby weighs 2.3-6.5 kg. The head and body length of the Black-flanked Rock-wallaby is 446-570 mm, with a tail length of  320-605 mm. They are dark to pale grey-brown above, paler on the chest and dark brown on the belly. The face is dark with a white or sandy-brown cheek stripe. Dark brown to black dorsal stripe from between the ears to below the shoulders. Coat is thick and woolly particularly around the rump, flanks and base of tail. Tail has a slight brush on the end. Pelage often becomes lighter and browner in summer.

The current distribution of the Black-flanked Rock-wallaby is Barrow Island, Cape Range Calvert Range, Wheatbelt and Salisbury Island. There are also translocated popualatiosn in Kalbarri NP, Cape Le Grand NP, Avon Valley NP and Paruna Sanctuary. The past distribution was Depuch and Barrow Islands, Cape Range, Little Sandy Desert (including Durba Hills, Calvert Range), Wheatbelt to Avon Valley NP, southern coastline, and Salisbury Island.

The Black-flanked Rock-wallaby is a shy and wary animal, feeding at night in open areas of grass close to shelter of rocks. The Black-flanked Rock-wallaby feeds on grasses, herbs, leaves and fruits. Rock-wallabies do not need to drink, and conserve water by sheltering from hot daytime temperatures in caves.

Sexual maturity is reached at 1-2 years. Breeding can be continuous after this time, but varies in response to seasonal rainfall. A feature of their reproduction is embryonic diapause, where the developing embryo becomes dormant until conditions are right for it to continue to develop.

As their common name suggests, rock wallabies show a pronounced preference for rocky habitats, especially those with extensive development of caves, crevices and overhangs that allow the animals to escape extremes of weather and to hide from predators. Outcrops that have large areas of smooth rock surfaces (such as granite inselbergs or steep cliffs) typically do not support rock wallabies. However, small areas of broken outcrop in association with such rock types can support small colonies of rock wallabies.

Information Source: Government of Australia, Department of Environment and Department of Parks and Wildlife Western Australia


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