Why are koalas endangered?
Koalas are not officially endangered, and are currently not in danger of extinction. They are at risk from numerous threats, however.
During the late 1800s, koalas became an export commodity for their fur, mostly for export to the USA. Due to koala numbers dwindling and public outrage, laws were enacted protecting the koala and imports were banned by the USA in the late 1920s. By this stage, the koala had been driven to extinction in South Australia.
New colonies have been introduced in South Australia and Western Australia, and within these protected environments, the koala is thriving. Man is their biggest threat, causing loss of food source and habitat loss. Increasing urbanisation results in more koalas being killed by cars, unsupervised dogs, bushfires and even directly by cruel and irresponsible people. In particular, koalas have a range of home trees, and their territory is often split by roads through new urban developments. As a result, when koalas try to wander from one of their home range trees to another, they are hit by cars. Domestic dogs pose another major threat to koalas in suburban fringes.
The conservation status of koalas varies from region to region in Australia, but in no state are they legislated as "endangered". For example, due to farming and land clearing, native koalas were eradicated from Western Australia and South Australia in the last century, but moves have been made to reestablish new colonies in both states. Currently, koalas are thriving on Kangaroo Island in SA, and in other isolated colonies.
Koalas are still listed as "common" in most parts of Queensland, but there are calls to list them as vulnerable in southeast Queensland, where koala numbers have dropped by about 60% in the last decade.
The NSW Government listed the koala as "rare and vulnerable" in 1992, and following protective measures which have seen koala populations regenerate, this has been changed to "vulnerable". The koala is, however, all but gone from the NSW central coast.
In Victoria, the koala is not on the threatened species list at all, and in some protected and remote regions, there is actually an overpopulation problem. They are considered to be "secure" in Victoria.
Despite urging by conservation groups since around 1992, Australia's federal government has refused to list the koala as vulnerable. Even international conservation groups cannot agree. Meanwhile, the International Union for Conservation of Nature (IUCN) lists the koala as "potentially vulnerable", while the US Endangered Species Act lists the koala as "threatened".
Having said that, however, just because the species is not officially threatened does not mean that they are free from threats to their future existence.
The chief threat to the koala is habitat loss. Koalas inhabit prime land which man has decided is better used for housing developments. Not only do the koalas lose their sources of shelter and food, they are subject to dog attacks and being hit by cars as suburbia extends further outwards. A prime example of this is southeast Queensland, where koala numbers have dropped to 60% less than what they were a decade ago, entirely due to increased development - and where they now face extinction by 2020.
Koalas are territorial, and they live in complex social communities where each member has a certain number of trees within its territory. When access to these trees is cut off by new roads, the koalas will still try to cross the road, and risk being hit. Relocation of koalas is rarely successful because their territorial and social habits are largely misunderstood.
Another significant factor is predation by introduced species such as dogs and foxes.
Koalas are also subject to the disease chlamydia, which affects the koalas' fertility, and eventually leads to their death. Currently, there is no cure for this disease. At the best of times, the koala is a slow breeder, usually producing just one joey a year.
For more information on threats to the koala, see the related link.