This Determination should be read in conjunction with the 2015 Determination relating to the Barrier Range Dragon.
NSW Scientific Committee - final determination
The Scientific Committee found that:
1.Ctenophorus decresii (Duméril and Bibron 1837), the Tawny Crevice-dragon is an agamid lizard. Males typically have a grey to grey-brown body, often with a series of cream, yellow or orange spots on the sides of the neck (Cogger 2000). Females are less colourful and have a brown to grey-brown body. Individuals reach approximately 220mm in total length.
2. The Tawny Crevice-dragon is distributed from Kangaroo Island, through the Mt Lofty Ranges and Flinders Ranges in south-eastern South Australia, and into north-western New South Wales (NSW). In NSW, the species is known from only three locations: Mutawintji National Park; a 1975 Australian Museum record from Koonenberry Mountain (70km north of Mutawintji); and Swan (1990) reported a specimen from west of Broken Hill.
3. The Tawny Crevice-dragon is highly specialised in its habitat requirements, being restricted to rock outcrops in ranges and gorges. The species is absent from apparently suitable habitat in other parts of its range in NSW. As such, its distribution is highly restricted and fragmented, and NSW populations may be genetically distinct from those in South Australia.
4. The Tawny Crevice-dragon is potentially threatened via disruption of habitat by introduced herbivores. Grazing of vegetation on and adjacent to rock outcrops by feral goats and rabbits, particularly during periods of drought, alters the environment surrounding Tawny Crevice-dragon habitat and may impede the movement of individuals between patches.
5. The Tawny Crevice-dragon is potentially threatened with predation by introduced predators, particularly the Feral Cat, Felis catus, but also the Red Fox, Vulpes vulpes. Predation by both the Feral Cat and the Red Fox are listed as Key Threatening Processes under the Act.
6. Small, isolated populations of Tawny Crevice-dragon may be competitively excluded by other reptile species. Circumstantial evidence indicates that Tawny Crevice-dragon occurrence in rock outcrops is inversely correlated to the occurrence of the Gidgee Skink, Egernia stokesii (G. Swan, pers. comm.).
In view of the above the Scientific Committee is of the opinion that the Tawny Crevice-dragon, Ctenophorus decresii (Duméril and Bibron 1837) is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival or evolutionary development cease to operate.
Proposed Gazettal date: 20/12/02
Exhibition period: 20/12/02 - 07/02/03
References
Cogger, H.G. (2000). 'Reptiles and Amphibians of Australia.' 6th edition (Reed Books: Chatswood.)
Swan, G. (1990). 'A Field Guide to the Snakes and Lizards of New South Wales.' (Three Sisters Productions: Winmalee.)