The domestic cat (
Felis catus) was first introduced into Australia in 1806 and by 1820 there were already significant numbers of feral cats surrounding Sydney, by 1890 90% of Australia had a feral population (Abbott, 2008). Cats are small carnivorous mammals that feed on small vertebrate and invertebrate animals. The introduction of cats to Australia had a profound effect on the small native wildlife. In the early part of the 20th century large populations of cats were released into gold mining sites in Western Australia, and as a form of population control for the rabbit and native rat (Dickman, 1996). This attempt at bio control caused for the populations of feral cats to increase tenfold and further affect the dwindling numbers of native birds and mammals within these areas.
Distribution of Feral Cats in Australia. Source: Feral.org.au, Assessed on the 13th of April 2014.
A major case study on the effect of feral cats on a species is the decline of the eastern barred bandicoot (Perameles gunnii) in Victoria, this population first started to decline in 1840 following settlement by Europeans who cleared land for grazing and introduced carnivorous species like the cat. By 1982 there was only a population of 1750 and as little as 150 by 1990. Scientists’’ believe that the introduction of feral cat species into the home range of the barred bandicoot increasing the mortality rate of the juveniles of the species thus causing the collapse of the population as a whole (Dickman, 1996).
Feral Cat in the Northern Territory. Source: Tim Doherty ECU. Assessed on the 13th of April 2014.
Feral cats within Australia have no known natural predator except for the Wedge-tailed eagle and the dingo, without these two species managing the population numbers, feral cats are the apex predators. Cats have become one of the greatest threats for native wildlife survival in Australia and are now one of the worst invasive species to be introduced to this country.
References:
- Abbott, I. (2008). Origin and spread of the cat, Felis catis on mainland Australia. Conservation Science Western Australia Journal. Vol. 7, 1 – 17.
- Dickman, C. (1996). Overview of the Impacts of Feral Cats on Australian Native Fauna. Australian Nature Conservation Agency – Institute of Wildlife Research. Pg, 1 – 97.
Very interesting and a good close-to-home example. I was wondering, have been any successful eradication programmes for feral cats? I’ve also been wondering about the rumours that cats are increasing in size due to low predation and a high abundance of food. Can you comment on this? Fascinating post.
ReplyDeleteI feel sorry for all the small wildlife (birds, lizards, frogs, melomys) around big towns/cities where people also let their pet cat roam at night and contribute to native animal deaths. Do you think that domestic cats are also a significant contributor to the predation of wildlife? Or is preventative measures (collar bells) effective enough and the feral population is the main concern?
ReplyDeleteUnfortunately house cats are still a big contributor to the deaths of native species. Many do not have bells that help to warn their prey, but also many owners leave their cats out all day and night. Allowing them to have a greater range of prey. In my own experiences many cats have overcome the sound of their bells, by walking and stalking in such a way that eliminates the sound of their bell - allowing them to creep up on their unaware prey.
DeleteVery interesting. I was wondering the same as Tasmin, are there any programs in place to help manage the feral cat population?
ReplyDeleteI'm conflicted about cats. I love them, hate what they do to our wildlife. Some months ago I saw a domestic cat attempting to kill a skink in my driveway - I shooed it away but never knew if the skink survived or not. This is probably one of the saddest videos I have ever seen: http://www.youtube.com/watch?v=1SIVirQ8Iyw
ReplyDeleteI strongly believe that if people want to keep a cat in this country, it should be indoors or in a cat run.