Download Pseudocheirus occidentalis, Western Ringtail Possum

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IUCN 2008: T18492A8336432
Pseudocheirus occidentalis, Western Ringtail Possum
Assessment by: Morris, K., Burbidge, A. & Friend, T.
View on www.iucnredlist.org
Citation: Morris, K., Burbidge, A. & Friend, T. 2008. Pseudocheirus occidentalis. The IUCN Red List of
Threatened Species 2008: e.T18492A8336432.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Mammalia
Diprotodontia
Pseudocheiridae
Taxon Name: Pseudocheirus occidentalis (Thomas, 1888)
Common Name(s):
• English:
Western Ringtail Possum, Ngwayir, Western Ringtail
Taxonomic Notes:
Pseudocheirus occidentalis is often considered to be conspecific with P. peregrinus (e.g., Groves 2005). It
is treated as a separate species here following the advice of the IUCN SSC Australian and Melanesian
Non-volant Mammal Specialist Group.
Assessment Information
Red List Category & Criteria:
Vulnerable B1ab(ii,iii,v) ver 3.1
Year Published:
2008
Date Assessed:
June 30, 2008
Justification:
Listed as Vulnerable because its extent of occurrence less than 20,000 km2, it has a severely fragmented
distribution, and there is a continuing decline in the area of occupancy, the extent and quality of its
habitat, and in the number of mature individuals.
Previously Published Red List Assessments
1996 – Vulnerable (VU)
1994 – Vulnerable (V)
1965 – Status inadequately known-survey required or data sought
Geographic Range
Range Description:
The Western Ringtail Possum has a restricted distribution in south-western Western Australia; it is found
along the coast from south of Bunbury to Waychinicup National Park (near Albany) and in suitable
habitat inland, most notably at Perup Nature Reserve and surrounding State forest near Manjimup
(Maxwell et al. 1996; de Tores 2008). It was recently recorded in stands of Peppermint near the Harvey
River and in Jarrah/Marri forest near Collie (north-east of Bunbury); however, the long term persistence
of the species in these areas is not confirmed (de Tores et al. 2004). The Western Ringtail was formerly
more widespread: in the 1970s it was known from Casuarina woodlands in the wheatbelt near Pingelly
(south-east of Perth), and it is thought to have once occurred throughout much of south-western
Western Australia (but not necessarily continuously distributed) (Maxwell et al. 1996; de Tores 2008).
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
1
Country Occurrence:
Native: Australia (Western Australia)
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
2
Distribution Map
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
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Population
Common in suitable habitat (de Tores 2008). The highest densities of this species were recorded in
Peppermint habitat near Busselton area; relatively high densities were found in Jarrah/Marri forest at
Perup (de Tores 2008). However, populations in coastal habitat (the majority of its range) are thought to
be declining due to habitat loss and fragmentation.
Current Population Trend: Decreasing
Habitat and Ecology (see Appendix for additional information)
The Western Ringtail Possum is associated with Peppermint (Agonis flexuosa). Along the coast, it is
found in Peppermint forest and woodland and in Tuart (Eucalyptus gomphocephala) forest, typically
with a Peppermint mid-story. Inland it is found in Jarrah (E. marginata), Wandoo (E. wandoo), and Marri
(Corymbia calophylla) forest (de Tores 2008).
This species is nocturnal and arboreal. It is a folivore; its preferred food is Peppermint foliage, or if that
is unavailable, myrtaceous species. Reproduction occurs year-round. The greatest number of young are
born in late autumn and winter; the least number of young are born in late summer. Litter size ranges
from 1 to 3 young, and is most commonly 1. At approximately 3 months age, the young emerge
permanently from the pouch. Female young generally remain in the home range of their mothers, while
male young disperse from their mother’s range when they are about 7 months old (at weight of 600 700 grams). The individual home range of this species varies in size, with larger sizes occurring in low
density populations. This species has been recorded to live more than six years (de Tores 2008).
There is thought to be some degree of competition and/or habitat partitioning with the Common
Brushtail where the two species co-occur, but the extent and effect of this competition is not clear.
However, there is negligible competition for nesting sites, as the Western Ringtail makes dreys (built of
vegetation), rather than using treeholes as does the Common Brushtail. The dreys are normally found in
the mid- to upper- canopy, but can occur lower to ground (de Tores 2008).
Systems: Terrestrial
Threats (see Appendix for additional information)
Coastal populations of the Western Ringtail Possum are threatened by habitat loss and fragmentation
associated with urban development (de Tores et al. 2004; de Tores 2008). Inland populations are
threatened by habitat modification, and also timber harvesting. Predation by introduced foxes (Vulpes
vulpes) is also a major threat to this species. In areas where fox populations are controlled, predation by
python (Morelia spilota imbricate) and by introduced cats is a major threat. Populations also may be
threatened by increasing fire intensities, and by burning operations associated with logging and clearing
(de Tores et al. 2004; de Tores 2008).
Conservation Actions (see Appendix for additional information)
Many of the known inland Western Ringtail Possum populations in the inland Perup area occur in
national forest, and are outside areas marked for logging. Some of these populations are the subject of a
research project quantifying threats to the species (de Tores et al. 2004). The species is listed as
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
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Vulnerable by Australian government.
The Western Ringtail species has been the subject of translocation programs in an attempt to mitigate
the effects of habitat loss (de Tores et al. 2004; de Tores 2008). In a recent review, de Tores et al. (2004)
noted that success of translocated populations has not been demonstrated at any of the release sites,
and that the primary release site (Leschenault Peninsula Conservation Park) has suffered a population
decline. This review also found that effective monitoring of the response of the species to fox control
programs is lacking outside of a few select translocations sites.
Recommended conservation measures include: implementation a monitoring program at sites selected
to represent the range of habitats used by the Western Ringtail in order to assess possum population
changes and responses to fox control and the impacts of other management practices; establishment of
a effective monitoring program at translocation sites; identification of sites of high conservation value to
the Western Ringtail; conservation of Western Ringtails in public lands managed by the Department of
Environment and Conservation (Western Australia); minimizing impacts of land developments;
education and liaison with towns with or near to Western Ringtail populations (de Tores et al. 2004).
Credits
Assessor(s):
Morris, K., Burbidge, A. & Friend, T.
Reviewer(s):
Lamoreux, J. & Hilton-Taylor, C. (Global Mammal Assessment Team)
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
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Bibliography
de Tores, P. J. 2008. Western Ringtail Possum, Pseudocheirus occidentalis. In: S. Van Dyck and R. Strahan
(eds), The mammals of Australia. Third Edition, pp. 253-255. Reed New Holland, Sydney, Australia.
de Tores, P. J., Hayward, M. W. and Rosier, S. M. 2004. The western ringtail possum, Pseudocheirus
occidentalis, and the quokka, Setonix brachyurus. Case studies: Western Shield Review, February 2003.
Conservation Science Western Australia 5: 235-258.
Groves, C. P. 2005. Order Diprotodontia. In: D. E. Wilson and D. M. Reeder (eds), Mammal Species of the
World, pp. 43-70. The Johns Hopkins University Press, Baltimore, Maryland, USA.
Maxwell, S., Burbidge, A. A. and Morris, K. 1996. The 1996 Action Plan for Australian Marsupials and
Monotremes. Australasian Marsupial and Monotreme Specialist Group, IUCN Species Survival
Commission, Gland, Switzerland.
Citation
Morris, K., Burbidge, A. & Friend, T. 2008. Pseudocheirus occidentalis. The IUCN Red List of Threatened
Species 2008: e.T18492A8336432. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.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: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
6
Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat
Season
Suitability
Major
Importance?
1. Forest -> 1.5. Forest - Subtropical/Tropical Dry
-
Suitable
-
3. Shrubland -> 3.8. Shrubland - Mediterranean-type Shrubby Vegetation
-
Suitable
-
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
-
-
-
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
-
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
-
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
-
Stresses:
2. Species Stresses -> 2.1. Species mortality
5. Biological resource use -> 5.3. Logging & wood
harvesting -> 5.3.5. Motivation
Unknown/Unrecorded
7. Natural system modifications -> 7.1. Fire & fire
suppression -> 7.1.3. Trend Unknown/Unrecorded
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.2.
Named species (Felis catus)
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.2.
Named species (Vulpes vulpes)
8. Invasive & other problematic species & genes ->
8.1. Invasive non-native/alien species -> 8.1.2.
Named species (Morelia spilota ssp. imbricata)
-
-
-
-
-
-
-
-
-
-
Conservation Actions in Place
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions in Place
In-Place Land/Water Protection and Management
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.en
7
Conservation Actions in Place
Conservation sites identified: Yes, over entire range
In-Place Species Management
Successfully reintroduced or introduced beningly: 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
4. Education & awareness -> 4.3. Awareness & communications
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
3. Monitoring -> 3.1. Population trends
Additional Data Fields
Population
Population severely fragmented: Yes
© The IUCN Red List of Threatened Species: Pseudocheirus occidentalis – published in 2008.
http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T18492A8336432.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: BirdLife International; Botanic Gardens Conservation International; Conservation
International; Microsoft; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas
A&M University; Wildscreen; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™