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Jewelled Southwest Ctenotus (Ctenotus gemmula (Swan Coastal Plain subpopulation))

The Jewelled Southwest Ctenotus is a small skink. The Swan Coastal Plain subpopulation is recorded in Western Australia’s Midwest and Swan regions. Species-specific habitat, ecology and seasonal activity are poorly documented, so works crews should use cautious, skink-appropriate survey and clearing practices. It is listed as DBCA Priority 3 in Western Australia, a DBCA priority category rather than a listing under the Biodiversity Conservation Act 2016. No national listing is given.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 3. This listing covers only Ctenotus gemmula (Swan Coastal Plain subpopulation) (Priority 3).

Seasonal planning

Taxon-specific activity and breeding months are not known. Use the full annual cycle as a general planning window and do not assume that any season is risk-free.

Seasonal evidence: Months of activity, breeding or movement have not been documented for this species.

Planning: Schedule surveys and precautionary checks around site access, approvals and suitable survey conditions; the row below is a planning prompt, not a species-specific activity calendar.

Seasonal categories do not represent confirmed activity, breeding or movement periods for this species.

  • Survey and clearing precautions: General planning window only. Species-specific seasonal activity data are not available; maintain appropriate survey and clearing precautions throughout the year.

Identification: Appearance and size

A few useful diagnostic characters are known, but a complete field description and size range have not been documented.

This is a small member of the Ctenotus labillardieri group. It has a broken white dorsolateral stripe and legs boldly blotched with black.

A body-length or total-length range, and a fuller description of colour and pattern, have not been documented.

Identification: Similar species

C. gemmula is distinguished from C. labillardieri by its broken white dorsolateral stripe and narrower subdigital calli. It is distinguished from C. delli by having eight rather than seven upper labials and boldly black-blotched rather than obscurely dotted legs.

Check the full suite of diagnostic characters before confirming an identification, especially where field views are brief.

Identification: Field signs

Species-specific tracks, scats, burrows, shed skins and other field signs have not been described.

Do not treat an unconfirmed sign or a brief sighting as a confirmed record. Photograph the animal where possible and have identification checked by a suitably experienced herpetologist.

Distribution: Known range

Records indicate a Western Australian distribution. Atlas records are name-matched records and should not be treated as a confirmed map of occupied habitat.

The Reptile Database gives Western Australia as the species’ distribution and South Perth as its type locality. Atlas of Living Australia records show 148 name-matched Western Australian records at 61 distinct 0.1-degree locations, spanning latitude -34.8 to -30.6 and longitude 115.3 to 125. Records outside Western Australia were excluded as likely errors.

Distribution: WA regions

The DBCA list flags the Midwest and Swan regions for this Swan Coastal Plain subpopulation. Regional listing does not establish that the species occurs at a particular development site.

Distribution: Record limitations

Atlas records are occurrence data, not evidence that suitable habitat is continuous between locations. Confirm site-level records and their identification and precision during desktop assessment.

Habitat: Species-specific information

Habitat used specifically by C. gemmula has not been documented. Regional reptile information provides context only, not a species-level habitat description.

The vegetation, soil, landform and habitat features selected by this species have not been documented. Do not assume that a site is unsuitable because it differs from a general description of Swan Coastal Plain environments.

Habitat: Regional context

A review of the northern Swan Coastal Plain describes a varied landscape that includes Quindalup, Spearwood and Bassendean dunes and reports reptiles across a range of habitats. This is broad reptile-community context and does not establish a preference of the jewelled southwest Ctenotus.

Foraging habitat: Diet and feeding

Species-specific diet, foraging behaviour and foraging locations have not been documented.

What this species eats and how it obtains food have not been documented. Do not infer a diet from its family or genus.

Foraging habitat: Site considerations

Because foraging habitat has not been described, assess the whole area that may be affected rather than selecting or excluding habitat based on an assumed feeding site.

Breeding habitat: Known breeding information

Ctenotus gemmula is egg-laying, but further breeding details are not known.

Ctenotus gemmula is oviparous. Breeding months, clutch size, egg-laying locations and nesting conditions have not been documented.

Breeding habitat: Precaution

Do not use an assumed breeding season to rule out risk. Before clearing, check for animals and potential refuges using the site assessment and precautionary procedures described below.

Sheltering habitat: Shelter information

Species-specific shelter sites and sheltering behaviour have not been described.

Whether this species shelters in burrows, beneath cover, in vegetation or in another refuge type is not known. These should not be presented as confirmed species traits.

Sheltering habitat: General skink search

As general practice for skink surveys, inspect suitable ground-level cover and vegetation carefully and look for animals in the places where they are exposed during the survey. This is a search approach for the group, not a known shelter preference of this species.

Threats: Regional pressures

Specific threats to this species have not been established. Regional reptile literature identifies pressures that may affect reptile communities on the northern Swan Coastal Plain.

A review of the Gnangara study area identifies habitat fragmentation or loss from urban development, declining groundwater, inappropriate fire regimes or wildfires, and Phytophthora infection as potential pressures on the regional reptile community. These are not confirmed taxon-specific impacts.

Threats: Status and uncertainty

The DBCA Threatened and Priority Fauna List describes the species as poorly known, known from several locations and not under imminent threat. No national listing is given.

Survey methodology: 1. Desktop assessment

Species-specific detectability and validated survey methods have not been documented. Use a cautious, documented approach and avoid interpreting non-detection as absence.

Review current DBCA information, available site records and atlas records, noting the date, spatial precision and identification confidence of each record. Check whether proposed works overlap the Swan Coastal Plain subpopulation’s mapped area and the flagged Midwest or Swan regions.

Survey methodology: 2. Habitat inspection

Walk the proposed disturbance footprint and adjacent areas before works. Record landform, vegetation, ground cover, disturbances and any potential animal refuges without assuming that a particular habitat feature is required by this species.

As general skink survey practice, search suitable ground-level cover and vegetation carefully. Minimise disturbance while inspecting and replace any moved cover in its original position.

Survey methodology: 3. Survey records

Record survey date, time, conditions, method, effort, observer, location and GPS accuracy, including areas not searched. Photograph diagnostic features when safe and permitted.

If no animals are found, report the result as non-detection under the survey conditions, not proof of absence. Seek expert identification for uncertain sightings.

Vegetation associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific vegetation association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Ecosystem associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific ecosystem association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Soil and substrate associations: Sandy soils or sand

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

A review of the northern Swan Coastal Plain describes a varied landscape that includes Quindalup, Spearwood and Bassendean dunes and reports reptiles across a range of habitats.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: WA.

Habitat use: general

Attribution gap: No sentence-level reference is attached to the original profile block. Review the profile bibliography; this candidate is not source-verified.

Water and wetland associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific water association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before habitat disturbance: 1. Plan and brief

Plan works on the basis that suitable habitat may be occupied, because species-specific habitat and seasonal use are not established.

Check approvals, current DBCA advice and known records before work starts. Brief the clearing crew and fauna spotter catcher on the identification limits, stop-work process and requirement to report suspected animals.

Before habitat disturbance: 2. Inspect and mark

Have a suitably experienced person inspect the footprint and accessible adjacent habitat before disturbance. Clearly mark the approved work area and any areas set aside for further assessment or avoidance.

Before habitat disturbance: 3. Prepare equipment

Set up a clear communication and incident-reporting process. Keep suitable, secure fauna containers and relevant permits or authorisations available if capture and relocation may be required.

During habitat disturbance: 1. Stage the work

Proceed cautiously, with a spotter catcher able to pause works if an animal or suspected refuge is encountered.

Keep clearing within the marked footprint and progress in manageable stages. Avoid unnecessary disturbance of retained vegetation and ground cover.

During habitat disturbance: 2. Watch and pause

Maintain active observation of the work area. Stop work if a possible Ctenotus gemmula is seen or an animal is exposed, injured or at immediate risk; allow the spotter catcher to assess the situation before work resumes.

During habitat disturbance: 3. Handle only as authorised

Do not allow untrained crew members to capture or handle wildlife. Any capture, temporary holding or relocation must be carried out by an appropriately authorised and competent person using approved procedures.

After habitat disturbance: 1. Inspect the work area

Close out the work with a check of the affected area and clear records of any animal encounters or changes to the work footprint.

After disturbance, check the work area and its edges for animals that may have been exposed or displaced. If an animal is found, pause nearby activity and follow the authorised fauna response.

After habitat disturbance: 2. Record and report

Document observations, non-detections, captures, injuries, relocations and any unexpected habitat features. Include coordinates and their accuracy, photographs where available, actions taken and the names of responsible personnel.

After habitat disturbance: 3. Review controls

Report incidents through the project’s approval and fauna-management processes. Review whether clearing limits, supervision or survey effort need to change before further work.

Rehabilitation actions: 1. Retain suitable areas

Habitat requirements for this species have not been described, so rehabilitation should avoid unverified species-specific assumptions.

Protect vegetation and ground cover outside the approved footprint. Avoid unnecessary changes to adjoining areas while the species’ site-level requirements remain uncertain.

Rehabilitation actions: 2. Restore disturbed ground

Rehabilitate temporary work areas in accordance with project approvals and the site’s restoration plan. Use locally appropriate methods and materials specified for the site rather than assuming a particular vegetation or substrate is required by this skink.

Rehabilitation actions: 3. Monitor outcomes

Record rehabilitation actions and any subsequent fauna observations. Treat later non-detection cautiously, as species-specific monitoring methods and detectability information are not available.

Sources