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The IUCN Red List of Threatened Species™
ISSN 2307-8235 (online)
IUCN 2008: T136379A22304640
Scope: Global
Language: English
Crocidura trichura, Christmas Island Shrew
Assessment by: Woinarski, J., Burbidge, A.A. & Lumsden, L.
View on www.iucnredlist.org
Citation: Woinarski, J., Burbidge, A.A. & Lumsden, L. 2016. Crocidura trichura. The IUCN Red List of
Threatened Species 2016: e.T136379A22304640. http://dx.doi.org/10.2305/IUCN.UK.20163.RLTS.T136379A22304640.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Mammalia
Eulipotyphla
Soricidae
Taxon Name: Crocidura trichura Dobson in Thomas, 1889
Common Name(s):
• English:
Christmas Island Shrew
Taxonomic Notes:
This taxon has been elevated to full species status by Hutterer (2005). It was originally regarded as "a
local variety" of the southeast Asian Crocidura fuliginosa. Based on morphological characteristics,
Jenkins (1976) described it as a subspecies of C. attenuata. Corbet and Hill (1992) questioned the
validity of it being conspecific with C. attenuata based on morphological characteristics. Ruedi (1995)
studied 11 specimens and concluded that they were different from C. attenuata.
Assessment Information
Red List Category & Criteria:
Critically Endangered () B1ab(iii,v); C2a(ii) ver 3.1
Year Published:
2016
Date Assessed:
July 18, 2015
Justification:
This species is listed as Critically Endangered (Possibly Extinct) given that its extent of occurrence is
approximately 88 km², it is found in one location, and its habitat is suffering continuing declines in
quality given increasing numbers and extent of invasive alien predator and competitor species. The
species has not definitely been seen since 1985, despite surveys, therefore it is now possibly extinct.
Date last seen: 1985
Previously Published Red List Assessments
2008 – Critically Endangered (CR) – http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T136379A4283212.en
Geographic Range
Range Description:
This shrew is endemic to Christmas Island (Australia).
Country Occurrence:
Possibly extinct: Christmas Island
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Distribution Map
Crocidura trichura
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Population
Crocidura trichura was 'extremely common' in 1900 (Andrews 1900) but was already rare in 1909
(Andrews 1909). Since 1909 there have been only four confirmed records: two individuals in 1958, and
two individuals in 1985. Several unconfirmed reports occurred between 1996 and 1998 but a survey
undertaken in 2000 to determine the status of the shrew were not successful in finding any individuals
(Meek 2000), and substantial survey effort since then has failed to record the species (Eldridge et al.
2014, Woinarski et al. 2014).
Current Population Trend: Decreasing
Habitat and Ecology (see Appendix for additional information)
The most recent records are from tall plateau rainforest in deep soils, and terrace rainforest with
shallow soils (Schulz 2002). It is not known whether or not this species can tolerate secondary growth,
but there appear to be no records around human settlements on the island (Schulz 2002). It was
recorded using holes in rocks and roots of trees as shelter, and foraging predominantly on small beetles
(Andrews 1900).
Systems: Terrestrial
Threats (see Appendix for additional information)
The reasons for the reduction of the population on Christmas Island are unknown. Schulz (2002) lists the
following potential threats in the Recovery Plan for this species: disease; the introduced yellow crazy ant
(Anoplolepis gracilipes) which is a dangerous threat for many terrestrial animals on Christmas Island;
habitat loss; habitat alteration (in part through the spread of invasive weeds); predation by both
introduced and natural predators (including cats and black rats); small population size; and mortality
due to road traffic. The most marked population decline occurred between 1900 and 1909, most likely
associated with the same disease (trypanosomisis) that caused the extinction then of Christmas Island's
two endemic rat species.
Conservation Actions (see Appendix for additional information)
There is a Recovery Plan for this species (Schulz 2002), which outlines the following needed actions:
investigate the taxonomic status of the shrew; investigate current status and distribution; develop
wildlife management program for potential habitat outside the Christmas Island National Park; control
abundance and spread of the yellow crazy ant; implement a community awareness programme;
establish a captive breeding population; implement effective management of any remaining wild
populations; identify and describe critical habitat; and identify threatening processes. This Recovery
Plan also outlines the following Management Practices: "No removal of primary plateau rainforest
within Christmas Island National Park; implementation of the Invasive Ants on Christmas Island Action
Plan; ensure tight quarantine controls to prevent accidental introductions of new diseases and exotic
pests; implement feral cat and black rat control programmes within primary plateau and terrace
rainforest; and maintenance of existing habitat quality or primary rainforest through strategies to
minimize spread of exotic weeds following the Weed Management Strategy". However, no individuals
have been reported since the Recovery Plan, despite limited targeted and much general biological
survey.
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Credits
Assessor(s):
Woinarski, J., Burbidge, A.A. & Lumsden, L.
Reviewer(s):
Amori, G.
Contributor(s):
Meek, P., Eldridge, M. & James, D.
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Bibliography
Andrews, C.W. 1900. A Monograph of Christmas Island (Indian Ocean). British Museum of Natural
History, London, UK.
Andrews, C.W. 1909. On the fauna of Christmas Island. Proceedings of Zoological Society, London 1909:
101-103.
Corbet, G.B. and Hill, J.E. 1992. Mammals of the Indo-Malayan Region: a Systematic Review. Oxford
University Press, Oxford, UK.
Eldridge, M.D.B., Meek, P.D., and Johnson, R.N. 2014. Taxonomic uncertainty and the loss of biodiversity
on Christmas Island, Indian Ocean. Conservation Biology 28: 572-579.
Hutterer, R. 2005. Order Soricomorpha. In: D.E. Wilson and D.M. Reeder (eds), Mammal Species of the
World, pp. 220-311. Johns Hopkins University Press, Baltimore, Maryland, USA.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org.
(Accessed: 07 December 2016).
Jenkins, P.D. 1976. Variation in Eurasian shrews of the genus Crocidura (Insectivora: Sodicidae). Bulletin
of the British Museum of Natural History 30: 271-309.
Meek, P. 2000. The decline and current status of the Christmas Island shrew Crocidura attenuata
trichura on Christmas Island, Indian Ocean. Australian Mammalogy 22: 43-49.
Ruedi, M. 1995. Taxonomic revision of shrews of the genus Crocidura from the Sunda Shelf and Sulawesi
with description of two new species (Mammalia: Soricidae). Zoological Journal of the Linnean Society
115: 211-265.
Schulz, M. 2002. Recovery Plan for the Christmas Island Shrew Crocidura attenuata trichura 2002 - 2007.
Environment Australia, Canberra, Australia.
Woinarski, J.C.Z., Burbidge, A.A. and Harrison, P.L. 2014. The Action Plan for Australian Mammals 2012.
CSIRO Publishing, Collingwood.
Citation
Woinarski, J., Burbidge, A.A. & Lumsden, L. 2016. Crocidura trichura. The IUCN Red List of Threatened
Species 2016: e.T136379A22304640. http://dx.doi.org/10.2305/IUCN.UK.20163.RLTS.T136379A22304640.en
Disclaimer
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External Resources
For Images and External Links to Additional Information, please see the Red List website.
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat
Season
Suitability
Major
Importance?
1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
-
Suitable
Yes
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat
Timing
Scope
Severity
Impact Score
1. Residential & commercial development -> 1.1.
Housing & urban areas
Ongoing
Minority (50%)
Negligible declines
Low impact: 4
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Minority (50%)
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Minority (50%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Majority (5090%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Whole (>90%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Whole (>90%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
-
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Agriculture & aquaculture -> 2.1. Annual &
perennial non-timber crops -> 2.1.2. Small-holder
farming
4. Transportation & service corridors -> 4.1. Roads &
railroads
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species
(Anoplolepis gracilipes)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Felis catus)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Rattus
rattus)
8. Invasive and other problematic species, genes &
diseases -> 8.2. Problematic native species/diseases
-> 8.2.1. Unspecified species
Negligible declines
Negligible declines
Unknown
Unknown
Unknown
-
Low impact: 4
Low impact: 4
Unknown
Unknown
Unknown
-
Conservation Actions in Place
(http://www.iucnredlist.org/technical-documents/classification-schemes)
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Conservation Actions in Place
In-Place Research, Monitoring and Planning
Action Recovery plan: Yes
Systematic monitoring scheme: No
In-Place Land/Water Protection and Management
Conservation sites identified: No
Occur in at least one PA: Yes
Percentage of population protected by PAs (0-100): 61-70
Area based regional management plan: Yes
Invasive species control or prevention: Yes
Conservation Actions Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions Needed
2. Land/water management -> 2.1. Site/area management
2. Land/water management -> 2.2. Invasive/problematic species control
3. Species management -> 3.2. Species recovery
3. Species management -> 3.4. Ex-situ conservation -> 3.4.1. Captive breeding/artificial propagation
4. Education & awareness -> 4.3. Awareness & communications
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
3. Monitoring -> 3.1. Population trends
Additional Data Fields
Distribution
Estimated area of occupancy (AOO) (km²): 10-135
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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Distribution
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) (km²): 88
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 1
Continuing decline in number of locations: No
Extreme fluctuations in the number of locations: No
Population
Number of mature individuals: 0-200
Continuing decline of mature individuals: Yes
Extreme fluctuations: No
Population severely fragmented: No
No. of subpopulations: 1
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No
All individuals in one subpopulation: Yes
Habitats and Ecology
Continuing decline in area, extent and/or quality of habitat: Yes
Movement patterns: Not a Migrant
© The IUCN Red List of Threatened Species: Crocidura trichura – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T136379A22304640.en
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The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership.
The IUCN Red List Partners are: Arizona State University; BirdLife International; Botanic Gardens
Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew;
Sapienza University of Rome; Texas A&M University; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™