What a great starting point thecommentator!
There's actually a huge amount of information freely available on the web to share which really does back up your point.
Pretty much any land mass which has been isolated from the rest of the world - e.g. australia, will have developed its own range of specialised flora
and fauna adapted to that particular environment.
It's commonly known that whenever you introduce man to any ecologically 'closed' environment, such as the Galapagos, or Australia (pretty much any
island), that non-indigenous predator animals have tended to follow and have disrupted the ecosystem.
In this respect, native animals have adapted in the presence of the area's own specialised predator population, but have little defence against
The introduction of non-native species to australia began mainly in the 1800s as the western world began to settle there.
With the arrival of European settlers, cats diffused inland and were spread from multiple coastal introductions in the period 1824-86 (Abbott, 2002).
By the 1850’s colonies of feral cats were established in the wild (Biodiversity Group Environment Australia, 1999). Considerable numbers of cats
were deliberately released in semi-arid and arid regions in the 1880’s as part of a misguided rabbit control program (Read and Bowen, 2001) and by
1890 nearly all the continent had been colonized by cats (Abbott, 2002). The rapid dispersal of cats throughout Australia was helped by the fact that
they have few natural predators or fatal diseases in the continent.
- source The impact of domestic cat (Felis catus) on wildlife welfare and conservation: Inbal Brickner
Now there's a few standout points that make cats fearsome predators in the Australian environment.
The below is a summary of some of the freely available research on the web - this issue has been studied for years and is not solely an Australian
issue. This is a summary of key points.
Cats Are Not a Natural Part of Many Ecosystems.
The domestic cat, Felis catus, is a descendant of the European and African wild cats.
Domesticated in Egypt more than 4,000 years ago, cats may be the most widespread predator in the world. In the U.S. , cats were not abundant until the
late 1800s when they were brought to help control burgeoning rodent populations associated with agriculture. Some people view cat predation of rodents
as beneficial, but native small mammals are important to maintaining biologically diverse ecosystems.
Owned cats have huge advantages over native predators.
They receive protection from disease, predation, competition, and starvation—factors
which control native predators such as owls, bobcats, and foxes. Cats with dependable food sources are not as vulnerable to changes in prey
populations. Unlike many native predators, cats are not strictly territorial. As a result, cats can exist at much higher densities and may out-
compete native predators for food. Unaltered cats are also prolific breeders. In warmer climates, a female cat can have 3 litters per year, with 4 to
6 kittens per litter.
Cats Transmit Disease to Wildlife
Unvaccinated cats can transmit diseases, such as rabies, to other cats, native wildlife and humans. Cats are the domestic animal most frequently
reported to be rabid to the Centers for Disease Control and Prevention. Cats are also suspected of spreading fatal feline diseases to native wild
Extensive studies of the feeding habits of free-roaming domestic cats have been conducted over the last 55 years in Europe, North America, Australia,
Africa, and on many islands. These studies show that the number and types of animals killed by cats varies greatly, depending on the individual cats,
the time of year, and availability of prey. Roughly 60% to 70% of the wildlife cats kill are small mammals; 20% to 30% are birds; and up to 10 are
amphibians, reptiles, and insects. However, birds can be up to 100% of a cat’s prey on some islands.
Australia is not the only place where this is a problem, a survey of the behaviour of domestic cats found that some free-roaming domestic cats kill
more than 100 animals each year. One well-fed cat that roamed a wildlife experiment station was recorded to have killed more than 1,600 animals
(mostly small mammals) over 18 months. Rural cats take more prey than suburban or urban cats. Birds that nest or feed on the ground are the most
susceptible to cat predation, as are nestlings and fledglings of many other bird species.
Cats on Islands:
Because some island bird populations evolved in the absence of mammalian predators, they have no defense mechanisms against them. When cats are
introduced or abandoned on an island, elimination of entire bird populations can result.
Cats in Habitat Islands:
Cats can have significant impacts on local wildlife populations, especially in habitat “islands” such as suburban
and urban parks, wildlife refuges, and other areas surrounded by human development.
Continued in next post
edit on 20-2-2012 by selfharmonise because: (no reason given)