* Clearing of eucalyptus forests for agriculture, housing, and other development destroys koala habitat.
* Fragmentation of eucalyptus forests by roads, railways, and other infrastructure makes it difficult for koalas to move between feeding and breeding grounds.
* Loss of tree hollows, which koalas use for shelter and nesting, is a major problem in many areas.
Climate change
* Climate change is causing the koala's habitat to become hotter and drier, which makes it more difficult for them to find food and water.
* More frequent and severe droughts are also causing koalas to lose their habitat.
* Rising sea levels are threatening koala populations in coastal areas.
Disease
* Koalas are susceptible to a number of diseases, including chlamydia, which is a sexually transmitted infection that can cause blindness, infertility, and death.
* Other diseases that affect koalas include the koala retrovirus (KoRV), which is a type of cancer, and the Australian lungworm, which is a parasitic worm that can cause respiratory problems.
Predation
* Koalas are preyed upon by a number of predators, including dingoes, wild dogs, and feral cats.
* Predation is a major cause of death for koalas, especially juveniles.
Human activity
* Koalas are often killed by cars, as they are slow-moving animals that are not always able to avoid traffic.
* Koalas are also sometimes shot or poisoned by humans, either intentionally or accidentally.
* Koalas can be affected by pesticides, herbicides, and other chemicals that are used in agriculture and forestry.