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Crocidura trichura 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Eulipotyphla Soricidae

Scientific Name: Crocidura trichura
Species Authority: 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 [top]

Red List Category & Criteria: Critically Endangered (Possibly Extinct) B1ab(iii,v); C2a(ii) ver 3.1
Year Published: 2016
Date Assessed: 2015-07-18
Assessor(s): Woinarski, J., Burbidge, A.A. & Lumsden, L.
Reviewer(s): Amori, G.
Contributor(s): Meek, P., Eldridge, M. & James, D.
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:

Geographic Range [top]

Range Description:This shrew is endemic to Christmas Island (Australia).
Countries occurrence:
Possibly extinct:
Christmas Island
Additional data:
Estimated area of occupancy (AOO) - km2:10-135Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:88
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:1Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

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
Additional data:
Number of mature individuals:0-200Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:1Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:Yes

Habitat and Ecology [top]

Habitat and Ecology: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
Continuing decline in area, extent and/or quality of habitat:Yes
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): 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 [top]

Conservation Actions: 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.

Citation: Woinarski, J., Burbidge, A.A. & Lumsden, L. 2016. Crocidura trichura. The IUCN Red List of Threatened Species 2016: e.T136379A22304640. . Downloaded on 25 February 2017.
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