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Authors: Tim Doherty (ECU)
The domestic cat (Felis catus) was introduced to Australia by Europeans and now inhabits all of mainland Australia, Tasmania and a number of offshore islands. Feral cats are opportunistic, generalist carnivores and their potential impacts include: predation, competition and disease transmission.
The recent Action Plan named feral cats as the number one threat to endangered mammals and Federal Environment Minister, Greg Hunt, has called for the ‘eradicat[ion] of all significant populations of feral cats’ within a decade.
Cats prey on at least 400 native and introduced vertebrates in Australia, including 123 birds, 157 reptiles, 58 marsupials, 27 rodents and 21 frogs. Cats have played a key role in the extinction of at least 22 mammals, and are a current threat to several threatened mammal and bird species. Most evidence for the population-level impacts of feral cats has been gleaned from historical patterns of decline and extinction, or from the failure of reintroduction attempts for threatened mammal species. The small amount of experimental work that has been done confirms that cats can suppress and exterminate small mammal populations.
The impacts of competition and disease transmission are less clear. Overlap in resource use between cats and native predators suggests competition may exist, although this has not been confirmed experimentally. Cats carry the parasite Toxoplasma gondii, which can cause death for many marsupials. High prevalence of Toxoplasma antibodies has been recorded in some marsupial populations, although it is not known how infection might alter their behaviour or susceptibility to predation.
Further research into the non-lethal impacts of cats is necessary, as well as a better understanding of the relationship between cats, other predators and their prey.
More on this Hot Topic:
– Link to peer-reviewed article via Austral Ecology –
If you have recently published an update on this topic, please contact the HT author for your research to be considered for addition to the evidence review.
Supporting Research
Title
Aims
Bettiol S. S., Obendorf D. L., Nowarkowski M. & Goldsmid, J. M. (2000) Pathology of experimental toxoplasmosis in eastern barred bandicoots in Tasmania. J. Wildl. Dis. 36, 141–144.
An experimental investigation to study the course of the disease and formation of antibodies following oral inoculation with a known number of viable T. gondii oocysts.
Burbidge A. A. (1999) Conservation values and management of Australian islands for non-volant mammal conservation. Australian Mammalogy. 21, 67–74.
Data on Australian landbridge islands were analysed to seek relationships between the extinction of mammals on islands and a number of variables related to the islands, the native mammal species that occur on them and the presence or absence of exotic mammalian predators.
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To provide a comparative pathology of toxoplasmosis in Australian marsupials.
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Reestablish populations of the burrow bettong and golden bandicoot at Gibson Desert Nature Reserve
Department of the Environment Water Heritage and the Arts (2008) Threat abatement plan for predation by feral cats. DEWHA, Canberra.
To establish a national framework to guide and coordinate Australia's response to the impacts of feral cats on biodiversity.
Doherty T.S., Davis R.A., van Etten E.J.B., Algar D., Collier N., Dickman C.R., Edwards G., Masters P., Palmer R. & Robinson S. (2015) A continental-scale analysis of feral cat diet in Australia. Journal of Biogeography, doi:10.1111/jbi.12469
To analyse the diet of the feral cat across its geographical range in Australia and on Australian territorial islands, seeking to identify biogeographical patterns in dietary composition and diversity and to use the results to consider how feral cats may best be managed.
Eymann J., Herbert C. A., Cooper D. W. & Dubey J. P. (2006) Serologic survey for Toxoplasma gondii and Neospora caninum in the common brushtail possum (Trichosurus vulpecula) from urban Sydney, Australia. J. Parasitol. 92, 267–272.
To investigate seroprevalence of T. gondii and N. caninum in urban brushtail possums and to analyze any association between seroprevalence and sex, age, body condition, and geographic location.
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To establish the prevalence of T. gondii among free-ranging (feral and stray) cat populations across Tasmania
Fancourt B. A., Nicol S. C., Hawkins C. E., Jones M. E. & Johnson C. N. (2014) Beyond the disease: Is Toxoplasma gondii infection causing population declines in the eastern quoll (Dasyurus viverrinus)? International Journal for Parasitology: Parasites and Wildlife. 3, 102–112.
Investigate the role of Toxoplasma gondii infection in the decline of eastern quolls in Tasmania
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Measure the impact of feral cats on the survival and population growth rates of a small-mammal species
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Reestablish populations of the rufous hare-wallaby (RHW) in the wild in the Tanami Desert
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To assess whether the density of feral cats is linked to the seroprevalence of T. gondii infection in Tasmanian wildlife, and to determine whether an increasing feral cat population may correspond to an increased level of risk to naive native marsupials of contracting acute toxoplasmosis.
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Document patterns and causes of decline and extinction in Australian mammals
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Investigate the response of reptiles and non-critical weight range mammals to the complete removal of rabbits, cats and foxes.
Moseby K. E., Read J. L., Paton D. C., Copley P., Hill B. M. & Crisp H. A. (2011) Predation determines the outcome of 10 reintroduction attempts in arid South Australia. Biological Conservation. 144, 2863–2872.
This study outlines the success or failure of each reintroduction at the Arid Recovery reserve and investigates factors affecting reintroduction outcomes.
Obendorf D. L., Statham P. & Driessen M. (1996) Detection of agglutinating antibodies to Toxoplasma gondii in sera from free-ranging eastern barred bandicoots (Perameles gunnii). J. Wildl. Dis. 32, 623–626.
To assess the prevalence of T. gondii infection in two eastern barred bandicoot populations in Tasmania.
Pan S., Thompson R. C. A., Grigg M. E., Sundar N., Smith A. & Lymbery A. J. (2012) Western Australian Marsupials Are Multiply Infected with Genetically Diverse Strains of Toxoplasma gondii (ed I. Igarashi). PLoS ONE. 7, e45147.
To use direct sequencing of tissue samples to determine the frequency of multiple infections and to examine the genetic diversity of the parasite (Toxoplasma gondii).
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Develop and test procedures for testing for T. gondii infection in macropods.
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To test whether it was possible to re-establish a self-sustaining population of brush-tailed bettongs NSW.
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Describe the pathological findings of acute, experimentally-induced toxoplasmosis in previously unexposed wallabies and compare these with the lesions in animals that survived challenge to become chronically infected with Toxoplasma.
Risbey D. A., Calver M. C., Short J., Bradley J. S. & Wright I. W. (2000) The impact of cats and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field experiment. Wildlife Research. 27, 223–235.
To test the response of small native mammals and reptiles and two species of introduced mammals to different levels of cat and fox activity.
Robinson S. A. & Copson G. R. (2014) Eradication of cats (Felis catus) from subantarctic Macquarie Island. Ecological Management & Restoration. 15, 34–40.
Summarise the execution and success of cat eradication at Macquarie Island. Recovery of breeding seabirds is reported.
Salo P., Korpimaki E., Banks P. B., Nordstrom M. & Dickman C. R. (2007) Alien predators are more dangerous than native predators to prey populations. Proceedings of the Royal Society B: Biological Sciences. 274, 1237–1243.
Performed a worldwide search of available field experiments in which the population densities of vertebrate (mammalian and avian) predators had been manipulated, and conducted a meta-analysis on the responses of their vertebrate prey.
Smith A. P. & Quin D. G. (1996) Patterns and causes of extinction and decline in Australian Conilurine Rodents. Biological Conservation. 77, 243–267.
Identify patterns in the decline and extinction of conilurine rodents.
Woinarski J. C. Z., Burbidge A. A. & Harrison P. (2014) The action plan for Australian mammals 2012. CSIRO Publishing, Melbourne.
Assess the conservation status of all Australian mammals.
Marlow N J, Thomas N D, Williams A A E, Macmahon B, Lawson J, Hitchen Y, Angus J & Berry O (2015) Cats (Felis catus) are more abundant and are the dominant predator of woylies (Bettongia penicillata) after sustained fox (Vulpes vulpes) control. Australian Journal of Zoology. doi:10.1071/ZO14024
To determine the role of cat predation in woylie population declines.
Woinarski, J.C.Z., Burbidge, A.A., Harrison, P.L., 2015. Ongoing unraveling of a continental fauna: Decline and extinction of Australian mammals since European settlement. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1417301112
Examine conservation status of Australian mammals