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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 Copyright: © 2016 International Union for Conservation of Nature and Natural Resources Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale, reposting or other commercial purposes is prohibited without prior written permission from the copyright holder. For further details see Terms of Use. 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. If you see any errors or have any questions or suggestions on what is shown in this document, please provide us with feedback so that we can correct or extend the information provided. 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 1 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 2 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 3 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 4 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 To make use of this information, please check the Terms of Use. 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 5 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 6 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 7 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 8 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™