Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Endangered as Egernia stokesii badia
Listed as Vulnerable as Egernia stokesii aethiops
Recovery Plan Decision Recovery Plan required, included on the Commenced List (1/11/2009).
 
Adopted/Made Recovery Plans Western Spiny-tailed Skink (Egernia stokesii) Recovery Plan (Western Australia Department of Environment and Conservation (WA DEC), 2012b) [Recovery Plan] as Egernia stokesii aethiops.
 
Western Spiny-tailed Skink (Egernia stokesii) Recovery Plan (Western Australia Department of Environment and Conservation (WA DEC), 2012b) [Recovery Plan] as Egernia stokesii badia.
 
Policy Statements and Guidelines Survey guidelines for Australia's threatened reptiles. EPBC Act survey guidelines 6.6 (Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC), 2011m) [Admin Guideline].
 
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Egernia stokesii aethiops.
 
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Egernia stokesii badia.
 
State Listing Status
WA: Listed as Vulnerable (Wildlife Conservation Act 1950 (Western Australia): September 2013) as Egernia stokesii badia
WA: Listed as Vulnerable (Wildlife Conservation Act 1950 (Western Australia): September 2013) as Egernia stokesii aethiops
Non-statutory Listing Status
IUCN: Listed as Endangered (IUCN Red List of Threatened Species: 2011.2)
Scientific name Egernia stokesii badia [64483]
Family Scincidae:Squamata:Reptilia:Chordata:Animalia
Species author  
Infraspecies author Storr, 1978
Reference  
Other names Egernia stokesii aethiops [26192]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific Name: Egernia stokesii badia

Common Name: Western Spiny-tailed Skink

There are three Egernia stokesii subspecies (AFD 2012):

  • E. s. badia, which occurs between Shark Bay and Minnivale in the WA wheatbelt and includes the population on Baudin Island, within Shark Bay, that was previously known as E. s. aethiops (Doughty 2012 pers. comm., cited in AFD 2012)
  • E. s. stokesii, which occurs on the Abrolhos Archipelago, 40 km off the WA town of Geraldton
  • E. s. zellingi, which occurs in central South Australia, west New South Wales and south-west Queensland.

The Western Spiny-tailed Skink is one of the larger subspecies of Egernia stokesii, growing to 194 mm (snout to vent length). Its skin is coloured with heavily keeled scales. It has a short, flattish, distinctively spiny tail (Chapple 2003; Wilson & Swan 2003) which it uses as anchorage within crevices when defending itself (Chapple 2003). There are two forms of Western Spiny-tailed Skink: a reddish brown form, with angular pale blotches arranged in irregular bands and a paler underside, in the northern and central wheatbelt; and a wholly black form in the Murchison region (Ecologia Environment 2010). As with all species in the Egernia genus, its fourth toe is much longer than its third (Wilson & Swan 2003).

The Western Spiny-tailed Skink is known to occur in a broad semi-arid area in south-west WA, between Shark Bay and Minnivale and east to Cue. A survey of the Western Australia Museum specimens indicated a declining collection rate (How et al. undated, 2003) with most records from private property (How et al. 2003). Much of area now known as the wheatbelt has been cleared since the 1960s and suitable microhabitat is now far less abundant (Shea & Smitt cited in Cogger et al. 1993), although an increasing number of skinks are being located in altered habitat under piles of wood, scrap metal or under buildings on private property (Hartley 2008).

Brown form - Wheatbelt area

A wheatbelt survey from south of Wubin to north of Morawa, and east to Koolanooka Spring and Rothsay, was conducted in 1998. Evidence of extant populations was found at Buntine Nature Reserve (NR), Bowgada NR, Perenjori, south of Rothsay, east of Morawa on Yalgoo Road, east of Wubin, near Kalannie, and east of the wheatbelt in the Yalgoo region. Both Buntine NR and the Perenjori area showed evidence of healthy populations (How et al. undated). A survey in 2008 also located the Western Spiny-tailed Skink at Mount Gibson Sanctuary, some 70 km from its nearest known population (AWC 2010).

Surveys for the subspecies in the central wheatbelt have shown a range contraction in the areas of Dowerin, Mount Marshall, Wyalkatchem, Trayning, Kellerberrin, Nungarin and Merredin (How et al. 2003). In 2008, a survey of the northern wheatbelt found just one population in a reserve within the survey area. However, a subsequent community awareness campaign in 2007–08 led to a number of records on private land, often under buildings or debris piles (Hartley 2008a).

Brown form - Shark Bay, including Baudin Island

Populations in the Shark Bay area are disjunct from the wheatbelt. There are records from Dirk Hartog Island, Denham (How et al. 2003), Baudin Island (AFD 2012), Useless Loop, Callagiddy Station, Woodleigh Station and Peron Peninsula (WA DEC 2012b). Overall, there are few collections in the area (WA DEC 2012b) and during one survey (the Carnarvon Basin Biological Survey in 1995–6) the subspecies was not seen (Maryan pers. comm. in How et al. undated; How et al. 2003).

Black form - Murchison region

In the Murchison region and northern wheatbelt, there is a darker coloured form, which has been recorded at 96 locations (Ecologia Environment 2010). The locations range from small, isolated stands of granite containing suitable habitat to larger, more extensive clusters of rock (Ecologia Environment 2010). It is not known to occur in coastal areas (all known localities are east of the Brand Highway) (WA DEC 2012b).

Between 2006–2009, Ecologia Environment (2010) conducted a vertebrate fauna assessment, as a result of the proposed (EPBC 2010/5500) Oakajee Port and Rail project in an area which extends slightly north of Geraldton and north-east through to Mileura, Western Australia. Surveys of the project area and surrounds have substantially increased the known population of the Western Spiny-tailed Skink (the black form) with the subspecies being discovered at 70 new locations in localised survey and a subsequent regional survey (Ecologia Environment 2009, 2010). To date, either individuals or scats have been found at 96 sites across the Murchison area (Ecologia Environment 2010).

Brown form - Wheatbelt area and Shark Bay

Most records of the brown form Western Spiny-tailed Skink are in York Gum (Eucalyptus loxophleba) woodland (Smith pers. comm. cited in Cogger et al. 1993; How et al. undated) with some records in Gimlet (E. salubris) and Salmon Gum (E. salmonophloia) woodland. Populations persist in woodland patches as small as one hectare and completely surrounded by wheatfields. Sites with the greatest number of individuals contain numerous fallen logs and were subjected to low-intensity grazing by domestic stock (How et al. undated).

Hollow logs are used as refuge sites in woodland habitat (Smith pers. comm. cited in Cogger et al. 1993; How et al. undated). Preferred refuges consist of piles of several, overlapping, hollow logs providing a combination of basking and shelter sites (How et al. undated). An increasing number of skinks are being located in altered habitat under piles of wood, scrap metal or under buildings on private property (Hartley 2008).

On Dirk Hartog Island, the species occurs in the transition zone between the Eucalyptus dominated south and the Acacia dominated interior (Wilson & Knowles 1988). Specimens have been found under limestone slabs in low, open heath and under corrugated sheet iron (Maryan et al. 1984).

Black form - Murchison region

During 2006–09 surveys, all records of the black form of Western Spiny-tailed Skink were on small, isolated stands of granite containing suitable habitat to larger, more extensive clusters of rock (Ecologia Environment 2010). Flat granite domes, with no boulders or crevices, do not support Western Spiny-tailed Skink (Ecologia Environment 2010). This is distinct from the tree hollow habitat of the brown form (How et al. 2003).

A female Western Spiny-tailed Skink was observed near Wubin giving live birth (viviparous) to one young in mid December (Nankivell 1976). Litter sizes of five young (range = 1–8; N = 29) of Egernia stokesii zellingi born between 15 February and 29 March, were reported from Hawker in South Australia (Duffield & Bull 1996). Around one third of E. stokesii offspring may die within their first year, but those that survive have a life span of 'several decades' (Duffield & Bull 1996, 2002 cited in Chapple 2003; How et al. 2003).

Western Spiny-tailed Skinks live in spatially and temporally stable groups of up to 17 individuals. Juveniles may remain in their natal group for up to five years (Duffield & Bull 2002). Gardner and colleagues (2001) found that these groups are comprised of breeding partners, their offspring and, in some cases, highly related adults, providing the first genetic evidence of a family structure in any lizard species. Family groups may also be a component of social organisation in the Western Spiny-tailed Skink (Bull et al. 2000; Main & Bull 1996).

The diet of the Western Spiny-tailed Skink is not known, but the species (Egernia stokesii) is known to be omnivorous, with juveniles feeding mainly on insects, and adults largely consuming plant material (Duffield & Bull 1998).

The Survey guidelines for Australia's threatened reptiles (DEWHA 2011m) includes survey design principles when planning a reptile survey and includes recommendations for survey methods for the Western Spiny-tailed Skink and its habitat (DEWHA 2011m).

The Western Spiny-tailed Skink has a distinctive behaviour of depositing faecal droppings outside of refuges in a pile or cluster (How et al. 2003).

Whilst the distribution of the Western Spiny-tailed Skink occurs mainly in the wheatbelt, the remaining habitat patches are threatened by clearing for agriculture, grazing and crop production (Cogger et al. 1993). The long-term survival of populations in grazed areas may be threatened as the presence of livestock may disrupt the dispersal of young between log piles (How et al. undated).

The following activities could result in a significant impact on the Western Spiny-tailed Skink (WA DEC 2012b):

  • the introduction of vertebrate predators, including rats (Rattus spp.), onto islands where the subspecies occurs.
  • the removal of available refugia, or the destruction or degradation of habitat or potential habitat.
  • the decrease in the connectivity of woodland remnants.
  • the removal of timber from woodland habitats.
  • increased grazing, compaction or salinity within identified or potential habitat.
  • prescribed fire or arson in woodland remnants.

The Western Spiny-tailed Skink (Egernia stokesii) Recovery Plan (WA DEC 2012b) identifies the following recovery actions:

  • Determine the essential habitat requirements of mainland WA populations.
  • Clarify the species' distribution, conservation status and population trends.
  • Identify threatening processes and techniques to mitigate their impact.
  • Manage known populations in remnant woodland areas.
  • Protect habitat and create new habitat, where required, for populations to persist.
  • Prevent the introduction of exotic, vertebrate predators and rats (Rattus spp.) onto islands occupied by the species.
  • Prevent illegal collection.
  • Engage landholders and local communities to promote awareness of the existence of the species and its conservation requirements.
  • Encourage landholders to remove or minimise the impact of stock and introduced herbivores on habitat, especially remnant woodlands.
  • Develop and implement conservation agreements with landholders and mining companies to retain habitat and link remnant woodland patches.
  • Manage the ongoing recovery process to ensure that actions are delivered and monitored effectively.
  • Develop a strategy to translocate at-risk populations to suitable sites when the need arises.

Nine Western Spiny-tailed Skinks were removed from private property in an "emergency translocation". They were relocated to a nearby nature reserve containing suitable woodland habitat. This was the first translocation of its kind for the subspecies and staff from the Western Australian Department of Environment and Conservation will monitor the progress of the translocated skinks (Hartly 2008). The Western Australian Department of Environment and Conservation has begun a community education program to encourage landholders to notify them of any populations found on their property.

Management documents relevant to the Western Spiny-tailed Skink are at the start of the profile.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation The Action Plan for Australian Reptiles (Cogger, H.G., E.E. Cameron, R.A. Sadlier & P. Eggler, 1993) [Cwlth Action Plan].
Agriculture and Aquaculture:Livestock Farming and Grazing:Grazing pressures and associated habitat changes Assessment of the central wheatbelt populations of the endangered skink Egernia stokesii badia (How, R.A., J. Dell & K. Aplin, undated) [Report].
Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat modification, destruction and alteration due to changes in land use patterns Egernia stokesii aethiops in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006hx) [Internet].
Climate Change and Severe Weather:Sea level rise:Inundation associated with climate change Inundation study (Environmental Resources Information Network, 2007) [Database].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) Egernia stokesii aethiops in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006hx) [Internet].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Predation, competition, habitat degradation and/or spread of pathogens by introduced species Egernia stokesii aethiops in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006hx) [Internet].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:unspecified Egernia stokesii aethiops in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006hx) [Internet].
Uncategorised:Uncategorised:threats not specified Egernia stokesii badiain Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006iv) [Internet].

Australian Faunal Directory (AFD) (2012). Australian Faunal Directory. [Online]. Available from: http://www.environment.gov.au/biodiversity/abrs/online-resources/fauna/afd/home.

Australian Wildlife Conservancy (2010). Wildlife Matters Summer Edition 2009/10. [Online]. Available from: http://www.australianwildlife.org/images/file/WMSummer0910.pdf.

Bull, C.M., C.L. Griffin, E.J. Lanham & G.R. Johnston (2000). Recognition of pheremones from group members in a gregarious lizard, Egernia stokesii. Journal of Herpetology. 34(1):92-99.

Chapple, D.G. (2003). Ecology, Life-History, and Behavior in the Australian Scincid Genus Egernia, with Comments on the Evolution of Complex Sociality in Lizards. Herptological Monographs. 17:145-180.

Cogger, H.G., E.E. Cameron, R.A. Sadlier & P. Eggler (1993). The Action Plan for Australian Reptiles. [Online]. Canberra, ACT: Australian Nature Conservation Agency. Available from: http://www.environment.gov.au/biodiversity/threatened/action/reptiles/index.html.

Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC) (2011m). Survey guidelines for Australia's threatened reptiles. EPBC Act survey guidelines 6.6 . [Online]. Canberra, ACT: DSEWPaC. Available from: http://www.environment.gov.au/epbc/publications/threatened-reptiles.html.

Duffield, G.A. & C.M. Bull (1996). Characterstics of the litter of the gidgee skink, Egernia stokesii. Wildlife Research. 23:337-342.

Duffield, G.A. & C.M. Bull (1998). Seasonal and ontogenetic changes in the diet of the Australian skink Egernia stokesii. Herpetologica. 54 (3):414-419.

Ecologia Environment (2009). OP Rail Proposal Tereestrial Fuana Assessment. Unpublished report for Oakajee Port and Rail Pty Ltd.

Ecologia Environment (2010). Oakajee Port and Rail Pty Ltd Egernia stokesii badia Summary of Results. Prepared for Oakajee Port and Rail Pty Ltd and submitted as part of EPBC 2010/5500.

Gardner, M.G., C.M. Bull, S.J.B. Cooper & G.A. Duffield (2001). Genetic evidence for a family structure in stable social aggregations of the Australian lizard Egernia stokesii. Molecular Ecology. 10(1):175-183.

Hartley, R. (2008). Rare skink gets communities talking. WATSNU. 14/2. [Online]. Species and Communities Branch, Western Australian Department of Environment and Conservation. Available from: http://www.dec.wa.gov.au/index2.php?option=com_docman&task=doc_view&gid=3224&Itemid=1.

Hartley, R. (2008a). Rare Skink Could Be In Your Backyard. Bush Notes Spring. [Online]. Northern Agricultural Catchment Councils (NACC). Available from: http://www.nacc.com.au/NACCWebSite/files/eb/eb56ea2f-bbad-4f2b-a1a4-dcb541e97f95.pdf.

How, R.A., J. Dell & D.J. Robinson (2003). The Western Spiny-tailed Skink, Egernia stokesii badia: Declining distribution in a habitat specialist. The Western Australian Naturalist. 24(2):138-146.

How, R.A., J. Dell & K. Aplin (undated). Assessment of the central wheatbelt populations of the endangered skink Egernia stokesii badia. Western Australian Museum. Unpublished.

Main, A.R & C.M. Bull (1996). Mother-offspring recognition in the Australian lizards, Tiliqua rugosa and Egernia stokesii. Animal Behaviour. 52:193-200.

Maryan, B., D. Robinson & R. Browne-Cooper (1984). New records of reptiles on Dirk Hartog Island, Western Australia. Western Australian Naturalist. 16(1):8-10.

Nankivell, R. (1976). Breeding of the larger spiny-tailed skink, Egernia stokesii. Western Australian Naturalist. 13:146-147.

Western Australia Department of Environment and Conservation (WA DEC) (2012b). Western Spiny-tailed Skink (Egernia stokesii) Recovery Plan. [Online]. Department of Environment and Conservation, Perth, WA. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/e-stokesii.html.

Wilson, S. & G. Swan (2003). A Complete Guide to Reptiles of Australia. Page(s) 480. Sydney: Reed New Holland.

Wilson, S.K. & D.G. Knowles (1988). Australia's Reptiles: A Photographic Reference to the Terrestrial Reptiles of Australia. Australia: Collins Publishers.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Egernia stokesii badia in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Wed, 16 Apr 2014 16:45:47 +1000.