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Kwongan Heath Shield-backed Trapdoor Spider (Idiosoma kwongan)

The Kwongan heath shield-backed trapdoor spider, Idiosoma kwongan, is a Western Australian member of the shield-backed trapdoor spider group. Records are from a small area of Western Australia, but its habitat and biology remain poorly known. It is DBCA Priority 1 fauna, a priority category for fauna that is poorly known and known from few locations, with none on conservation lands.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 1.

Seasonal planning

Seasonal activity, breeding and survey periods for I. kwongan have not been documented. Plan surveys and disturbance controls year-round unless site-specific evidence supports a different approach.

Species-specific timing: Not recorded.

Planning approach: Treat potential burrow habitat as relevant throughout the year.

Seasonal timing is not known for this species.

  • Survey and clearance planning: Planning window only. No species-specific seasonal activity or breeding period is documented; survey and apply precautionary controls year-round.

Identification: Appearance and size

Field identification information for I. kwongan is limited. Treat suspected burrow signs as requiring careful assessment rather than assuming they belong to this species.

Idiosoma species have a hardened, shield-like area on the abdomen. The genus is described as having enlarged, hardened abdominal structures associated with defensive shielding.

A species-specific description of I. kwongan’s appearance and size has not been recorded.

Identification: Similar species

Other Idiosoma species occur in Western Australia. Field characters distinguishing I. kwongan from them have not been documented.

Do not identify a spider to species from a burrow or general shield-backed appearance alone. Seek expert identification where a record may affect works.

Identification: Field signs

A scientific paper recommends surveys for burrow presence or absence across the shield-backed trapdoor spider group, but does not give a confirmed description of I. kwongan burrows.

Record the position and condition of any suspected burrow, and avoid disturbing it until an appropriately qualified ecologist has assessed it.

Distribution: Known range

Records indicate a restricted known distribution in Western Australia, although the species remains poorly known.

Atlas of Living Australia records show eight Western Australian records at six distinct 0.1-degree locations. The reported coordinate bounds are latitude -30.1 to -29.4 and longitude 115 to 115.3.

These records describe the mapped occurrences, not necessarily the full range or current occupancy. No named collection localities are available.

Distribution: WA regions and status

The DBCA list flags the Midwest and Wheatbelt regions for this species. The records do not establish how it is distributed within either region.

It is DBCA Priority 1 fauna, described as poorly known and known from few locations, with none on conservation lands. No national listing is given.

Habitat: Available habitat information

The species’ precise habitat requirements and the vegetation conditions needed to support it have not been established.

A project assessment concerning I. kwongan refers to Kwongan heath habitat in the surrounding area, but does not give a species-specific habitat description or confirm which parts are occupied.

The common name also refers to Kwongan heath, but does not provide a complete habitat account.

Habitat: Site assessment

Before works, map native vegetation and undisturbed ground across the development area, including areas resembling the Kwongan heath described in the project assessment.

Do not assume that apparently similar vegetation is occupied or unoccupied without survey evidence.

Foraging habitat: Diet and foraging

Species-specific feeding habitat and diet have not been documented.

No prey, feeding period or species-specific foraging behaviour has been reported for I. kwongan.

General information about prey taken by other Idiosoma species should not be used to describe this species’ diet.

Foraging habitat: Precaution for works

Retain undisturbed native ground and vegetation around suspected burrows while their status is assessed. No particular foraging zone or buffer distance has been identified for this species.

Include the location of any suspected burrow and the surrounding proposed work area in site planning, rather than assuming the spider uses only the burrow entrance.

Breeding habitat: Known information

Breeding habitat and timing for I. kwongan are poorly known.

A 2026 taxonomic paper reports the first female specimens of I. kwongan. It does not report breeding observations or describe nests, eggs or young.

Do not apply breeding dates or behaviour reported for other Idiosoma species to this species.

Breeding habitat: Precaution

Treat a suspected occupied burrow as potentially important throughout the year because species-specific breeding periods are unknown.

Avoid excavation or other direct disturbance until an ecologist has assessed the site and agreed on an appropriate response.

Sheltering habitat: Burrow information

Burrows are relevant to survey planning for shield-backed trapdoor spiders generally, but the form and dimensions of I. kwongan burrows have not been documented.

A revision of the shield-backed trapdoor spider group recommends surveying for burrow presence or absence. It does not provide species-specific burrow measurements or entrance characteristics for I. kwongan.

Use this genus-level information to guide cautious searches, not as a confirmed description of this species’ shelter.

Sheltering habitat: Ground disturbance

Avoid driving over, grading, compacting or excavating around suspected burrows before they have been assessed.

Mark suspected burrows discreetly and communicate their locations to the clearing supervisor and fauna spotter catcher.

Threats: Conservation context

The species is poorly known, and a complete species-specific threat assessment has not been recorded.

The DBCA Priority 1 category identifies I. kwongan as poorly known and known from few locations, with none on conservation lands.

A 2018 assessment in a scientific paper considered the species data deficient for conservation assessment. A 2026 paper reports new records and a range extension, but does not quantify the species’ population or conservation status.

Threats: Development risks

A project assessment identifies clearing of native vegetation and possible fauna injury or mortality from vehicles and machinery as terrestrial fauna risks. It also notes indirect risks such as weeds, dieback, spills and altered fire regimes. These are project-level risks, not a confirmed species-specific threat assessment for I. kwongan.

The project assessment specifies a research program to improve knowledge of I. kwongan, reflecting the information gaps for this species.

Survey methodology: 1. Desktop assessment

Plan surveys around the limited species-specific information and the recommendation to check for burrow presence or absence across the shield-backed trapdoor spider group.

Review current DBCA information, available occurrence records, previous survey reports and proposed clearing boundaries. Atlas of Living Australia records give a broad occurrence envelope, not precise site localities.

Map native vegetation and undisturbed ground that may be relevant, including Kwongan heath where present. Do not infer occupancy from vegetation type alone.

Survey methodology: 2. Field search

Search suitable undisturbed ground carefully for possible burrow signs. A scientific review of the group recommends rigorous surveys for burrow presence or absence.

Record search effort, survey conditions, mapped signs and areas not searched. Do not excavate suspected burrows as a routine survey method.

Survey methodology: 3. Identification and records

Photograph and map suspected signs where this can be done without disturbance. Seek specialist review when species identity is uncertain.

A scientific review recommends developing non-lethal and non-destructive methods for obtaining genetic material from wild animals. Any sampling should follow relevant approvals and specialist advice.

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

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

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

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. Confirm information

Plan works on the basis that the species is poorly known and that the available mapped records do not rule out its presence at a site.

Check current DBCA priority fauna information and consult a suitably experienced ecologist before finalising clearing limits.

Review existing records, site vegetation, previous survey coverage and planned access routes. Document uncertainty where surveys or identification are incomplete.

Before habitat disturbance: 2. Survey and mark

Arrange a pre-disturbance survey that includes careful searches for potential burrows in areas proposed for clearing or ground disturbance.

Map and clearly communicate any suspected burrows and agreed exclusion areas to supervisors, machinery operators and fauna spotter catchers.

Before habitat disturbance: 3. Brief the crew

Brief workers on the possibility of ground-dwelling trapdoor spiders, the locations of flagged signs and the requirement to stop work if an unexpected burrow or spider is found.

Agree in advance who will assess finds and how work will be paused, recorded and restarted.

During habitat disturbance: 1. Work to limits

Use careful, staged work practices and respond promptly to suspected burrows or spiders encountered during clearing.

Keep machinery and vehicle movements within approved work areas and away from flagged suspected burrows and exclusion areas.

Use the agreed clearing sequence and avoid unnecessary ground disturbance or compaction outside the authorised footprint.

During habitat disturbance: 2. Stop and assess

If a suspected burrow or spider is encountered, stop work in the immediate area and prevent further disturbance while a qualified person assesses it.

Do not excavate, plug, collect or relocate the animal unless an ecologist has determined the appropriate action under applicable approvals and procedures.

During habitat disturbance: 3. Record and report

Record the find location, date, work activity, photographs where safe, and any action taken. Notify the environmental lead and follow the project reporting process.

Resume work only after the site has been assessed and the agreed controls are in place.

After habitat disturbance: 1. Check the site

After works, retain a clear record of findings and check that agreed protection measures remain effective.

Inspect flagged areas and work boundaries for evidence of accidental encroachment or damage to suspected burrows.

Report any injury, mortality, newly found signs or damage promptly through the project environmental process.

After habitat disturbance: 2. Update records

Compile survey effort, locations of suspected signs, identification outcomes, incidents and management actions in the project fauna record.

Share verified records with the relevant environmental and fauna specialists and submit them to the appropriate authority or database where required.

Rehabilitation actions: 1. Restore disturbed ground

Species-specific rehabilitation methods and success criteria for I. kwongan have not been established.

Rehabilitate disturbed areas in line with project approvals and the site rehabilitation plan, while avoiding further disturbance to retained native vegetation and any flagged burrows.

The project assessment describes progressive rehabilitation as a project control, but does not establish a species-specific method or outcome for I. kwongan.

Rehabilitation actions: 2. Monitor and adapt

Record rehabilitation actions and inspect for erosion, weeds or other issues that could compromise the agreed site outcomes.

Do not treat revegetation as proof that habitat for I. kwongan has been restored. Species-specific habitat requirements and rehabilitation criteria have not been recorded.

Sources