This species is now known as Strophurus elderi (Stirling & Zietz, 1893) [NSW Government Gazette No. 113, 25 November 2011, Pages 6715-6716].
NSW Scientific Committee - final determination
The Scientific Committee found that:
1. The Jewelled Gecko is a dark brown to velvety grey or black lizard that reaches an approximate total length of 65-75mm. The species takes its name from the numerous scattered white spots that cover the body (Cogger 2000). Individuals are able to exude a viscous fluid from the dorsal surface of the tail that is repellent to the lizard-eating predator, Burton's Legless Lizard, Lialis burtonis (Wilson and Knowles 1988).
2. The Jewelled Gecko is distributed through the arid regions of north-western Australia, through central Australia to southern Australia. In NSW records of the species are largely confined to the south-west of the state in two broad areas with 20 records between Mildura and Menindee, including four records from Tarawi Nature Reserve, and 21 records between Menindee and Robinvale, with five records from Mallee Cliffs National Park. All but two of these were recorded after the 1970s. In addition, an individual was recorded in 1982 from Yathong Nature Reserve in the state's central-west. No additional records have been reported from this location.
3. The Jewelled Gecko is restricted to spinifex, Triodia species, habitat on red soils, usually in association with mallee woodlands (Sadlier et al. 1996). The species is entirely dependent on spinifex clumps for shelter and foraging sites and is found within relatively large, mature clumps in areas that are not frequently burnt.
4. Degradation and loss of Jewelled Gecko habitat occurs in association with land use. Grazing by introduced herbivores within mallee-spinifex habitat affects the density and structure of spinifex. Cattle, goats and sheep graze spinifex seed heads, and in the process trample the clumps (Maher et al. 1995). Grazing also affects the density of adjacent shrubs and ground cover, which offer shelter for individual geckos moving between spinifex clumps. Disturbance through trampling by stock also degrades the soil structure and facilitates weed invasion.
5. Alteration of natural fire regimes, in association with landuse, directly affects Jewelled Gecko habitat. Pastoralists utilise fire to reduce the density of spinifex and promote the growth of vegetation that is more palatable to stock (Maher et al. 1995). However, such practices may be non-patchy and too frequent, reducing the amount of habitat and affecting the ability of individuals to recolonise burnt areas (Masters 1996).
6. The diets of both the Feral Cat, Felis catus, and European Red Fox, Vulpes vulpes, include a significant proportion of reptilian prey (Sadlier et al. 1996). The degree of threat to the Jewelled Gecko from predation by these introduced species is unknown; this impact in concert with threats to the habitat of the Jewelled Gecko may potentially be significant.
7. The fragmented distribution of the Jewelled Gecko increases the likelihood of local populations becoming extinct as a result of stochastic events. Although the species has recently been recorded from within National Parks and Wildlife Service estate, this may not ensure the species' long-term survival in NSW.
8. In view of the above points, the Scientific Committee is of the opinion that the Jewelled Gecko Diplodactylus elderi Stirling and Zietz 1893 is likely to become endangered in New South Wales unless the circumstances and factors threatening its survival or evolutionary development cease to operate.
Associate Professor Paul Adam
Chairperson
Scientific Committee
Proposed Gazettal date: 25/06/04
Exhibition period: 25/06/04 - 06/08/04
References
Cogger HG (2000) 'Reptiles and amphibians of Australia.' (Reed Books: Chatswood).
Maher M, Norris D, Ridge T, Robinson M (1995) 'The Ledknapper Spinifex: its people, plants and animals.' (Land Information Centre: Bathurst).
Masters P (1996) The effects of fire-driven succession on reptiles in spinifex grasslands at Uluru National Park, Northern Territory. Wildlife Research 23, 39-48.
Sadlier RA, Pressey RL, Whish GL (1996) 'Reptiles and amphibians of particular conservation concern in the Western Division of New South Wales: distributions, habitats and conservation status.' NSW National Parks and Wildlife Service, Occasional Paper 21, Hurstville.
Wilson SK, Knowles DG (1988) 'Australia's reptiles: a photographic reference to the terrestrial reptiles of Australia.' (Collins Publishers: Sydney).