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Christmas Island Shrew (Crocidura trichura)

The Christmas Island Shrew is a small mammal endemic to Christmas Island, an Australian territory in the Indian Ocean. Its relevant habitat includes the island’s plateau and terrace rainforests.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Seasonal planning

No species-specific activity or breeding months were found in the published sources used. Use the following as a works-planning prompt, not as seasonal biology.

Seasonal knowledge: Not documented in the sources used.

The month values are a general planning prompt only and do not represent known activity or breeding months for Crocidura trichura.

  • Plan checks before disturbance: General planning window only. Check the work area before disturbance whenever works are scheduled.

Identification: Appearance

This small, long-nosed shrew weighs about 5 to 6 g. It is known for high-pitched calls.

This small, long-nosed shrew weighs about 5 to 6 g. It is known for high-pitched calls.

Identification: Confirming identity

Confirm the identity of any suspected record with a specialist and a photograph or voucher, as required by the relevant permit.

Distribution: Known range

The species occurs on Christmas Island and is endemic to the island.

The species occurs on Christmas Island and is endemic to the island.

Distribution: National mapping

The Commonwealth species distribution model (SNES) maps where the species or its habitat is known, likely or may occur. Use it with local records and site inspection.

Habitat: Habitat

It occupies tall plateau rainforest with deep soil and terrace rainforest with shallow soil. Whether it can live in secondary growth is unknown.

It occupies tall plateau rainforest with deep soil and terrace rainforest with shallow soil. Whether it can live in secondary growth is unknown.

Foraging habitat: Diet

It feeds mainly on small beetles.

It feeds mainly on small beetles.

Breeding habitat: Breeding

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Sheltering habitat: Shelter

It shelters in holes in rocks and among tree roots.

It shelters in holes in rocks and among tree roots.

Threats: Threats

Rainforest clearance for phosphate mining, introduced diseases associated with black rats, and invasive predators have been identified as threats to any surviving shrews. Yellow Crazy Ant population explosions and human ant-control methods may also pose risks.

Rainforest clearance for phosphate mining, introduced diseases associated with black rats, and invasive predators have been identified as threats to any surviving shrews. Yellow Crazy Ant population explosions and human ant-control methods may also pose risks.

Threats: Works risk

Clearing rainforest for development, including mining, can remove habitat used by the shrew. Works that clear plateau or terrace rainforest could therefore affect its habitat.

Survey methodology: 1. Species-specific methods

Use methods consistent with the Commonwealth survey guidelines and engage a specialist with the right permits.

Surveys have used pitfall traps, remote cameras and bat detectors to detect the shrew’s high-pitched calls. Targeted field surveys have also been identified as a way to investigate its distribution and status.

Survey methodology: 2. Commonwealth guidance

For EPBC Act referrals, survey effort and methods should be consistent with the survey guidelines for Australia's threatened mammals, read with the Significant impact guidelines 1.1.

Survey methodology: 3. Limits

A non-detection is not proof of absence. Match survey timing to the species and season, and record effort.

Vegetation associations: Rainforest or vine thicket

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

It occupies tall plateau rainforest with deep soil and terrace rainforest with shallow soil.

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: not specified.

Habitat use: general

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: Rocky, stony or shallow ground

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

It occupies tall plateau rainforest with deep soil and terrace rainforest with shallow soil.

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: not specified.

Habitat use: general

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 disturbance: 1. Desktop and approvals

Confirm whether the project could affect the species before works begin.

Check national mapping, state records and recent surveys for the site. An action likely to have a significant impact on this nationally listed species needs EPBC Act referral, and state permits apply where it is state listed.

Before disturbance: 2. Plan to avoid

Design the footprint, timing and access to avoid known or likely habitat, and brief crews on what to look for and who to call.

During disturbance: 1. Controls

Keep works inside the approved footprint and conditions.

Fence or mark habitat to be retained and keep machinery, stockpiles and spoil out of it.

During disturbance: 2. Stop and report

If the species is found unexpectedly, stop work at that spot and contact the project ecologist and the relevant agency.

After disturbance: 1. Records

Record outcomes.

Record sightings, habitat lost or retained and any injury or death, and report them under the approval conditions.

Rehabilitation: 1. Restore

Restore disturbed habitat where possible.

Reinstate disturbed ground with local species, return logs, rocks and litter, and control weeds and erosion until the site is stable.

Sources