Trichosurus vulpecula (brushtail possum)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- Habitat List
- Biology and Ecology
- Impact Summary
- Threatened Species
- Risk and Impact Factors
- Prevention and Control
- Links to Websites
- Principal Source
- Distribution Maps
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IdentityTop of page
Preferred Scientific Name
- Trichosurus vulpecula (Kerr, 1792)
Preferred Common Name
- brushtail possum
Other Scientific Names
- Trichosurus fuliginosus Ogilby, 1831
International Common Names
- English: common brushtail possum; possum
Local Common Names
- Germany: Fuchskusu
Summary of InvasivenessTop of page
The brushtail possum (Trichosurus vulpecula) is a solitary, nocturnal, arboreal marsupial introduced from Australia. It damages native forests in New Zealand by selective feeding on foliage and fruits and also preys on bird nests and is a vector for bovine tuberculosis. This species has been nominated as among 100 of the "World's Worst" invaders.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Mammalia
- Order: Marsupalia
- Family: Phalangeridae
- Genus: Trichosurus
- Species: Trichosurus vulpecula
DescriptionTop of page
Trichosurus vulpecula are cat-sized phalanger (2-4kg) with a bushy, prehensile tail, strong claws, a pointed snout, brown eyes and prominent ears, which are naked on the inside. The fur is thick and woolly; either grey or "black". Grey individuals have a grizzled back and sides, with paler (whitish) underparts, a dark snout and chin and a pink nose. The sternal gland stains a streak of brown fur on the chest (most marked in adult males). The tail is thick and cylindrical, turning to black at around mid point, with a naked underside towards the end. "Black" individuals are actually a dark brown, tinged with rufous, paler on the forequarters and underside, with an almost entirely black tail. Adult females have a forward-opening pouch with two mammaries. Adult males have testes in a pendulous scrotum, situated anterior to the penis.
DistributionTop of page
Native range: Australia.
Known introduced range: New Zealand.
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Present, no further details|
|Managed forests, plantations and orchards||Present, no further details|
|Disturbed areas||Present, no further details|
|Urban / peri-urban areas||Present, no further details|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Present, no further details|
|Natural grasslands||Present, no further details|
|Riverbanks||Present, no further details|
|Wetlands||Present, no further details|
|Scrub / shrublands||Present, no further details|
|Coastal areas||Present, no further details|
Biology and EcologyTop of page
In its native Australia, the brushtail possum (Trichosurus vulpecula) feeds mainly on Eucalyptus leaves, but high levels of phenolics, terpenoids and other chemical defences in eucalypt foliage limits the intake of any one species. In New Zealand forests a high proportion of plant species is palatable and brushtail possum diets include a wide variety of foliage and fleshy fruits. The New Zealand plants most favoured by possums tend to be those producing foliage or fruits high in carbohydrate. In addition to their staple diet of foliage and fruits, possums also feed on flowers, the pollen cones of introduced pines, insects, and bird eggs and nestlings.
Sexual: 1 - 2 young per year. Females can breed at one year of age.
Reproduction is highly seasonal with the main breeding season in autumn. A secondary season in spring sometimes occurs when nutrition is good. Gestation is 17-18 days. Single newborn young (c. 0.2g) crawl into the pouch and attach to a teat. Most development occurs within the pouch, where they remain for 120 - 140 days. Young remain with the mother (initially riding on her back) for a further 100 days or more, becoming independent from 240 -270 days old. Females may mature at one year old; males at 15 months or more.
Impact SummaryTop of page
ImpactTop of page
Trichosurus vulpecula have multiple impacts, as a browser of forest vegetation, frugivore, competitor for tree hollows, predator of invertebrates and bird nests, and disease vector. Long term changes in forest structure and composition (including canopy collapse in extreme cases) can result from sustained possum browsing pressure. Some highly palatable and chemically "unprotected" plant species are so preferred by brushtail possums that their selective browsing can result in local plant extinctions. Effects on native wildlife include depletion of fruit crops, competition for tree hollows, and predation by possums on invertebrates and the eggs and nestlings of birds (including threatened species). Possums are vectors of bovine tuberculosis, and consequently pose a significant threat to cattle, deer and dairy industries.
Threatened SpeciesTop of page
|Threatened Species||Conservation Status||Where Threatened||Mechanism||References||Notes|
|Eudyptes pachyrhynchus (Fiordland crested penguin)||VU (IUCN red list: Vulnerable); USA ESA listing as threatened species||New Zealand||Predation||US Fish and Wildlife Service, 2010|
Risk and Impact FactorsTop of page Impact outcomes
- Ecosystem change/ habitat alteration
- Negatively impacts animal health
- Threat to/ loss of native species
- Pest and disease transmission
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Preventative measures: Harbouring and releasing brushtail possums (Trichosurus vulpecula) in New Zealand was made illegal in the 1940s (Cowan, 2005)
Cultural: Bounties were offered for possums in New Zealand between 1951 and 1962. In this 11 year period about 8.2 million bounties were paid but the bounty system probably encouraged the illegal spread and release of possums (Cowan, 2005).
Physical: Possums are trapped for fur throughout New Zealand but pelts from the South Island are worth more. In periods of high fur prices trappers may have a significant impact on possum populations but this control is limited to accessible areas (Cowan, 2005; Marks, 2006). Possums were eradicated from Rangitoto and Motutapu islands using a combination of methods including aerial 1080 drops (estimated to kill 93% of the population), trapping using leg hold traps and ground based shooting with dogs. Helicopters fitted with forward looking infra-red cameras were used to identify areas of possum activity at night. The eradication of possums from both islands (joined by a small causeway) took 6 years (Mowbray, 2002). Possums have been removed from a number of areas surrounded by predator proof fences (e.g. Karori Sanctuary in Wellington) although the fences need constant monitoring for breaches that would allow possums and other introduced mammals back into the fenced area.
Chemical: Possum control in New Zealand using poison is coordinated by three main groups: the Animal Health Board (to minimise the Tb risk to domestic stock); the Department of Conservation (to protect forests and native wildlife); and the Regional Councils (for Tb control and conservation reasons). 1080 in carrots or cereal baits is spread using helicopters to treat large areas. Smaller areas are generally treated using ground based poisoning utilising toxins such as 1080, cyanide (in paste or capsule form), cholecalciferol, and various anticoagulants. Ground based poison control is often backed up with physical methods such as trapping and shooting (Cowan, 2005).
Biological: Two methods of biological control are being investigated: immunological interference with fertility and disabling the normal hormonal control of reproduction (Cowan, 2005). Tompkins and Ramsey (2007) investigated different methods of distributing fertility control vaccines through bait stations and concluded that the delivery method would not affect success of fertility control operations. Instead, the success depends on vaccine characteristics, namely: “its expense relative to existing tools, its longevity in the field, and its efficacy at reducing female breeding success”.
Integrated management: Possum control using poisons (particularly aerial drops) frequently controls rodent species and in turn predators such as mustelids and feral cats through secondary poisoning.
BibliographyTop of page
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Bomford, M., 2003. Risk Assessment for the Import and Keeping of Exotic Vertebrates in Australia. Bureau of Rural Sciences, Canberra. http://www.feral.org.au/feral_documents/PC12803.pdf
Boudouresque, C. F., Meinesz, A. and Gravez, V. 1994. First International Workshop on Caulerpa taxifolia, Nice, France, 17-18 janvier 1994. GIS Posidonie, Marseille, France. 392pp.
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Boudouresque, C. F., Meinesz, A., Ribera, M. A. and Ballesteros, E. 1995. Spread of the green alga Caulerpa taxifolia (Caulerpales, Chlorophyta) in the Mediterranean: possible consequences of a major ecological event. Scientia Marina 59 (supl.1): 21-29.
Brown and Sherley., 2002. The eradication of possums from Kapiti Island, New Zealand. In Turning the tide: the eradication of invasive species: 46-52. Veitch, C.R. and Clout, M.N.(eds). IUCN SSC Invasive Species Specialist Group. IUCN. Gland. Switzerland and Cambridge. UK.
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Coquillard, P., Thibaut, T., Hill, D. R. C., Gueugnot, J., Mazel, C. and Coquillard, Y. 2000. Simulation of the mollusc Ascoglossa Elysia subornata population dynamics: application to the potential biocontrol of Caulerpa taxifolia growth in the Mediterranean Sea. Ecological Modelling 135: 1-16.
Cowan, P. E. 1990. The Brushtail Possum. The Handbook of New Zealand Mammals. King, C. M. (ed.) Oxford University Press.
Cowan, P.E. 2005. Brushtail possum. In. C.M. King (Ed.) Handbook of New Zealand Mammals, Second Edition, pp56-80. Oxford University Press, Melbourne.
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Guerriero, A., Meinesz, A., d'Ambrosio, M. and Pietra, F. 1992. Isolation of toxic and potentially toxic sesqui- and monoterpens from the tropical green seaweed Caulerpa taxifolia which has invaded the region of Cap Martin and Monaco. Helvetica Chimica Acta.
Hay, C. H. 1990. The dispersal of sporophytes of Undaria pinnatifida by coastal shipping in new Zealand, and implications for further dispersal of Undaria in France. British Phycological Journal 25: 301-313.
IUCN/SSC Invasive Species Specialist Group (ISSG)., 2010. A Compilation of Information Sources for Conservation Managers Involved in the Prevention, Eradication, Management and Control of the Spread of Invasive Alien Species that are a Threat to Native biodiversity and Natural Ecosystems.
Lemée, R., Pesando, D., Issanchou, C. and Amade, P. 1997. Microalgae: a model to investigate the ecotoxicity of the green alga Caulerpa taxifolia from the Mediterranean Sea. Marine Environmental Research 44: 13-25.
Lovegrove, T. G., C. H. Zeiler, B. S. Greene, B. W. Green, R. Gaastra, and A. D. MacArthur., 2002. Alien plant and animal control and aspects of ecological restoration in a small 'mainland island': Wenderholm Regional Park, New Zealand. In Turning the tide: the eradication of invasive species: 155-163. Veitch, C.R. and Clout, M.N.(eds). IUCN SSC Invasive Species Specialist Group. IUCN. Gland. Switzerland and Cambridge. UK.
Marks, Kathy., December 2006. Alien invasion: How the possum became public enemy No 1 in The Independent: Nature http://www.independent.co.uk/environment/nature/alien-invasion-how-the-possum-became-public-enemy-no-1-429933.html
Meinesz A., Cottalorda J. M., Chiaverni D., Cassar N and De Vaugelas J. (1998) Suivi de l'invasion de l'algue tropicale de l'algue tropicale Caulerpa taxifolia en Mediterranée: situation au 31 décembre 1997. Lab. Environnement Marin Litoral, Université de Nice-Sophia Antipolis publications: 1-238.
Meinesz, A. and Hesse, B. 1991. Introduction et invasion de l'algue tropicale Caulerpa taxifolia en Méditerranée nord-occidentale. Oceanologia Acta 14(4): 415-426.
Montague, T. L. 2000. The brushtail possum: Biology, impact and management of an introduced marsupial. Manaaki Whenua Press, New Zealand.
Mowbray, 2002. Eradication of introduced Australian marsupials (brushtail possum and brush tailed rock wallaby) from Rangitoto and Motutapu Islands, New Zealand. In Turning the tide: the eradication of invasive species: 226-232. Veitch, C.R. and Clout, M.N.(eds). IUCN SSC Invasive Species Specialist Group. IUCN. Gland. Switzerland and Cambridge. UK.
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Perez, R., Lee, J. Y. and Juge, C. 1981. Observations sur la biologie de l'algue japonaise Undaria pinnatifida (harvey) Suringar introduite accidentellement dans l'étang de Thau. Science et Peche 325: 12pp.
Ribera, M. A., Ballesteros, E., Boudouresque, C. F., Gómez, A. and Gravez, V. 1996. Second International Workhop on Caulerpa taxifolia. Barcelona, Spain, 15-17 December 1994. Publicacions Universitat de Barcelona: 1-457.
Tasman District Council (TDC) 2001. Tasman-Nelson Regional Pest Management Strategy http://www.tdc.govt.nz/pdfs/Regional-Pest-Mmgt-Strategy.pdf
Tompkins, D.M. and Ramset, D. 2007. Optimising bait-station delivery of fertility control agents to brushtail possum populations. Wildlife Research 34: 67-76.
ReferencesTop of page
US Fish and Wildlife Service, 2010. In: Endangered and Threatened Wildlife and Plants; Determination of Threatened Status for Five Penguin Species. 75(148) US Fish and Wildlife Service, 45497-45527. http://www.gpo.gov/fdsys/pkg/FR-2010-08-03/pdf/2010-18884.pdf
ContributorsTop of page
- Reviewed by: Dr. Mick Clout, University of Auckland, New Zealand.
- Last Modified: Thursday, May 31, 2007
Distribution MapsTop of page
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