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Vasse Pachysaga (Pachysaga strobila)

The Vasse Pachysaga is a large, cumbersome katydid known only from its type specimen, collected near Vasse in Western Australia. Its precise habitat and ecology are poorly known, so works in the South West should take a precautionary approach. DBCA Priority 1 is a priority category, not a listing under the Biodiversity Conservation Act 2016.

Conservation status

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

Seasonal survey planning

Seasonal activity, breeding and movement information for the Vasse Pachysaga is not known. Do not use a seasonal non-detection as evidence of absence.

Seasonal timing for the species is unknown; months shown are a general planning prompt, not evidence of activity.

  • Survey timing: No species-specific seasonal window is known. This is a planning window only; use repeated searches and consider a carefully planned night survey as general katydid practice.

Identification: Appearance and size

Species-specific identification information is limited. Confirm any suspected record with a suitably experienced entomologist.

The Vasse Pachysaga is described as large and cumbersome. It is unusual among its genus because it lacks a hind wing.

No measurements, colour details or further diagnostic features are documented.

Identification: Similar species

Other Pachysaga species have a distinctive red, yellow or grey hind wing, which this species lacks.

No field key or full comparison with other katydids is available. Do not identify a specimen from size or wing appearance alone.

Identification: Field signs

Species-specific calls, tracks, feeding signs, eggs and other field signs have not been documented.

Katydids as a group are generally long-legged, long-antennaed and nocturnal, but these group traits are not sufficient to confirm this species.

Distribution: Known range

The known record is very limited. Do not assume the species is absent because no public coordinates are available.

The species is known only from its type specimen, found near Vasse in Western Australia. Attempts to locate additional specimens have not succeeded.

Patches of natural vegetation near the coast are worth investigating, although there are no further confirmed records.

Distribution: WA regions and status

The DBCA list flags the South West region. The common-name range descriptor is Busselton-Donnybrook.

The species is DBCA Priority 1, described as poorly known and known from few locations, with none on conservation lands. It has no national listing. DBCA Priority 1 is a priority category, not a listing under the Biodiversity Conservation Act 2016.

Habitat: Reported context

The species' precise habitat requirements have not been established.

The species is associated with the Southwest Australia biodiversity hotspot and is reported from near Vasse.

Heath or mixed woodland is described for the Austrosaginae subfamily generally. This is broad context, not a confirmed habitat description for the Vasse Pachysaga.

Habitat: Site assessment

Natural vegetation patches near the coast are worth investigating. Vegetation structure, soil, microclimate and any required habitat features are not specified.

Treat remaining native vegetation near the known area as potentially relevant until site-specific survey provides better evidence.

Foraging habitat: Diet

The species' diet and foraging habitat have not been documented.

No food plants, prey or other diet information is known for the Vasse Pachysaga.

Foraging habitat: Precaution on site

Avoid assuming that a particular plant is a food source. During site checks, record any observed feeding activity and the plant or substrate involved without disturbing the animal.

Breeding habitat: Known information

Breeding biology and breeding habitat are poorly known.

Mating behaviour, egg-laying sites, eggs, nymphs and breeding seasons have not been documented.

Breeding habitat: Precaution on site

Do not assume that a site is free of breeding activity because no eggs or young are found. Minimise disturbance to native vegetation and record any suspected eggs or immature katydids for expert review.

Sheltering habitat: Known information

Species-specific sheltering sites and resting behaviour are not known.

Where this katydid shelters, rests or spends the day has not been identified.

Sheltering habitat: Precaution on site

When checking vegetation or ground cover, work slowly and avoid unnecessary handling or removal of material. Retain inspected habitat in place wherever practicable.

Threats: Reported pressures

Substantial habitat modification around Vasse has been reported, but there is no current site-by-site assessment.

Agricultural activity has devastated the immediate area around Vasse, with little natural vegetation remaining.

Roadside verges are burned each year. These burns promote introduced grasses and plants, including Gladiolus.

Threats: Implications for works

The very limited known record and scarcity of natural vegetation near Vasse make it important to check remaining suitable-looking vegetation carefully.

The species' response to development activities is not established, and the effect of any individual pressure has not been quantified.

Survey methodology: 1. Desktop assessment

The species has proved difficult to relocate, and no validated survey protocol is known. Use repeated, low-impact searches and specialist identification.

Check the proposed works footprint and nearby natural vegetation, including coastal patches and roadside remnants, for records and habitat information. Public WA coordinates are not available.

Consult an experienced katydid taxonomist or entomologist before survey so observations can be assessed appropriately.

Survey methodology: 2. Field search

Search native vegetation methodically and with minimal disturbance. Katydids are generally nocturnal, so include a carefully planned night search where safe and appropriate. This is general practice, not a proven species-specific method.

Record date, time, weather, location, vegetation and search effort. Photograph suspected individuals in place where possible, and avoid collecting unless authorised and necessary for expert identification.

Survey methodology: 3. Interpret results

Several attempts to locate additional specimens have been unsuccessful. A non-detection therefore does not establish absence.

Report survey limitations clearly and seek expert review of any suspected record before using it to guide works.

Vegetation associations: Woodland

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

Heath or mixed woodland is described for the Austrosaginae subfamily generally.

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.

Vegetation associations: Heath

Heath or mixed woodland is described for the Austrosaginae subfamily generally.

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.

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. Plan the footprint

Plan works to avoid unnecessary loss or disturbance of native vegetation, particularly near the known area.

Map native vegetation remnants and roadside verges within and next to the works area. Avoid clearing natural vegetation where the design allows, and minimise the footprint in remaining habitat.

Before habitat disturbance: 2. Survey and brief crews

Arrange a suitably timed, low-impact fauna survey before clearing and provide the field team with the species' limited identification information.

Brief spotter catchers and clearing crews to pause work if a suspected Vasse Pachysaga is found, retain the observation location and contact the project ecologist for assessment.

During habitat disturbance: 1. Stage clearing

Proceed cautiously because the animal may be difficult to detect and its sheltering habits are unknown.

Clear in a controlled sequence with a fauna spotter catcher present, where required by the project or approvals. Keep clearing to the approved footprint and avoid unnecessary disturbance to adjacent vegetation.

During habitat disturbance: 2. Respond to a sighting

Pause work in the immediate work area, avoid handling the animal unless necessary for its safety and authorised, and have the ecologist or a suitably experienced specialist assess it.

Record the location and circumstances, take photographs where practical, and follow project approvals and relevant fauna-handling requirements before work resumes.

After habitat disturbance: 1. Record and report

After works, document outcomes and check that retained vegetation has not been affected beyond the approved footprint.

Document survey effort, sightings, non-detections, any fauna response and the extent of clearing. Submit suspected records for expert confirmation and appropriate reporting.

After habitat disturbance: 2. Check retained habitat

Inspect the work boundary and nearby retained vegetation for unintended damage or disturbance. Address access, storage or other site activities that could affect these remnants.

Rehabilitation actions: 1. Restore disturbed areas

Rehabilitation should support native vegetation, while recognising that species-specific restoration requirements are not known.

Rehabilitate temporarily disturbed areas with suitable local native vegetation and prevent avoidable spread of introduced plants. Rehabilitation is not a substitute for avoiding impacts to existing natural remnants.

Rehabilitation actions: 2. Monitor and adapt

Monitor rehabilitation for establishment of native vegetation and introduced plant growth. Record observations of katydids, but do not assume that the species has recolonised unless confirmed.

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