Threats to koalas

Threats to Koalas

The following are some of the biggest threats to the Australian koala population

Loss of Habitat- the Single biggest threat.

Deforestation, urbanisation, bush fires and encroachment have diminished natural habitats for koalas to grow, thrive and reproduce. Removal of habitat is the single biggest threat to the koala population, as well as all other native wildlife in Australia.The vast majority of this loss of vegetation occurs as a result of urban development, agriculture, mining and the expansion of existing infrastructure.

An individual adult male coastal koala occupies up to 100 hectares; an area he occupies for life. Koalas live in a social hierarchy with higher-ranking animals occupying the best locations and lower-ranking koalas occupying lower quality habitats.

Due to habitat loss, the koala is now under threat, making it a sentinel animal for forest-dwelling species in this country. If the koala is wiped out, this will precipitate the demise of other fauna and flora. Australia holds the shameful title of having the greatest number of extinctions of mammals in the world.

Disease

Koalas in the wild face the threat of diseases (like chlamydiosis) that, without diagnosis and proper treatment, will quite often lead to death.
Chlamydia is a major disease threat to our Koala population. It is an obligate, intracellular bacteria that is found in many species of bird and mammals worldwide. Unfortunately, Koalas suffer from both bacterium species Chlamydia pneumonia and Chlamydia pecorum.

Learn More

How does Chlamydia occur in Koalas?

It is likely that many strains of this disease have existed for a very long time within the koala population, acting as natural population regulators. In the early 1800s Europeans settling in Australia brought with them agricultural livestock such as sheep, cattle and pigs. Records from this period reported koalas “curled up at the base of trees, with diseased eyes and looking very sick”. Research using DNA sequencing has shown that some of the current strains of chlamydia are very similar to those found in cattle, sheep and pigs. It is highly likely that these strains of chlamydia “jumped ship” from agricultural animals into koalas – how this transmission occurred is still largely unknown. These “newer” strains are considered to be more virulent exposing koalas to diseases they have not had enough evolutionary time to adapt to and thus the disease had a major impact on wild koala populations even as far back as the 1800s. 

What does it look like in Koalas?

Chlamydia can exhibit as ocular disease (infecting the eyes) or the urogenital form (infecting the reproductive tract and the urinary tract) or koalas can exhibit both at the same time. Some koalas can appear quite healthy with no clinical signs of the disease but can still carry the pathogen (sub-clinical) and may never become unwell during their lifetime.In the ocular (eye) form of this disease the conjunctiva of the eye is normally the first point of noticeable infection. It becomes red and inflamed, the tissue begins to swell and a purulent (pus filled) discharge can often commence. As the disease progresses, it can invade the cornea (the front of the eye itself) and/or the conjunctival tissue creates an inflammatory response where the tissue becomes so swollen and prolific it completely covers the eye and the koala is unable to see. In advanced stages the koala is rendered blind and they usually starve to death as they are unable to locate trees.In an urogenital chlamydia infected koala the wall of the bladder can become so thickened and fibrotic that it becomes ineffective in both holding and expelling urine – the koala becomes incontinent and continually drips urine hence the term “wet bottom” to describe a sick koala. The internal wall of the bladder can also become so inflamed and swollen, the koala continually passes blood and purulent material. This sort of damage is simply not treatable with drugs and is both incredibly painful for the koala and distressing for the human carer to witness.
Interestingly, a much higher expression of this disease occurs in areas of disturbed habitats such as peri urban (beside) and urban environments.
This is also the case in mining areas with reduced vegetation, in areas of high bushfire impact and now in areas suffering from hotter, drier conditions. This higher expression of disease in these areas makes sense as koalas are either forced closer together to compete for resources or further apart and struggle to find food and shelter. Genetic inbreeding occurs in areas of fragmented habitat and areas of poor soil quality. In good healthy forested areas that are undisturbed, the incidence of chlamydial disease is very low. 
It is worth noting here that both the NSW and Qld koala populations are struggling to survive far more than the Victorian and South Australian populations.  

If the koala is admitted to care in the early stages of ocular infection, there is usually an excellent chance of successful treatment.

How we help

When koalas are first admitted into the hospital, they undergo a full health screen examination. This is done under anaesthesia with the koala given a full physical assessment, blood tests are done and a PCR swab (Polymerase chain reaction which detects chlamydia cells) and finally an ultrasound to check the urogenital tract and other internal organs that may be affected by this disease.  Urinary and reproductive tract infection is a much more complex scenario. Whilst the disease chlamydia does not favour either sex and will happily infect both male and female koalas alike, the female koala has “more plumbing” to deal with and therefore more complications can arise. Every time a koala becomes sick, more structural damage is done internally, no matter how well they may appear. Some koalas become infected for the first time and become so diseased, they deteriorate and die in a matter of weeks. Much of how koalas respond to this disease is driven by genetics, soil quality and soil moisture/nutritional status of trees, multiple pressures from disturbance of habitats, climatic conditions and how virulent the actual strain of the disease is in the area they live. If during this assessment the internal structural damage is so advanced, that the future quality of life for the koala is very poor then the kindest thing to do from an animal welfare perspective is to euthanase the koala whilst it is under anaesthesia. At the Koala Hospital (and across the country) relieving animals of severe pain is a major component of what we do.

What does treatment involve?

As a specialist folivore, koalas have evolved to cope with the toxic compounds found in eucalypt leaf by a number of mechanisms. Koalas have what is dubbed a “super liver” which is designed to break down and metabolise these toxins and eliminate them from the body. The koala also has a large gut system plus a two-metre caecum filled with a suite of micro-organisms (microbiome) all designed to break down the leaf allowing uptake of nutrients.  This makes treatment difficult as antibiotics that are capable of killing the chlamydia in koalas also have the potential to kill off the important microbiome and as a result can kill the koala. There is a fine line between successful treatment and causing harm to the koala.  Other medications such as non-steroidal anti-inflammatory drugs are metabolised and eliminated by the “super liver” before they are able to do the job they are designed to do.  If the koala does not have disease that is too far advanced to be treated, then the koala will commence a 4-6 week treatment plan. At the end of the treatment plan, the koala is held for a further two weeks and “left alone”, then the koala is given a full health screen under anaesthesia again and if everything has been deemed “successful”, the koala is eartagged, microchipped and released back to its capture point. As the prevalence and severity of the disease is deeply related to Koala habitat, prevention is just as important as treatment. There needs to be far better management strategies and tighter more robust legislation put in place by both the Federal and State governments to ensure their protection well into the future. There needs to be large amounts of quality undisturbed forested environments free of humans set aside where koalas can live undisturbed to breed and remain healthy.

Injury and Attack

As a result of diminishing habitats, koalas face the frequent threat of injury or death from motor vehicles, as well as dog attacks.
Adult Koalas occupy a large home range in which they stay for their entire lives. The loss of parts of their habitat due to construction of roads, highways, shopping centres, housing estates and other human infrastructure have major implications for wild koala populations. Roads built within the koalas home range become obstacles over which Koalas must cross for the koala to find food, shelter and mates. This creates a great risk for the Koala to be hit be a moving vehicle as often they are hard to spot for the majority of motorists.

How to prevent dog attacks

  • Choose a breed that is less likely to attack wildlife
    Plant trees in the front of a yard (not near powerlines) in preference to backyards.
  • If koala trees are in a backyard – try to fence off where the tree or trees are to keep dogs away. Erect timber runners from the tree to the fence to allow the koala to not have to go down to the ground.
  • Koalas often walk along the tops of fences to get from A to B. It is not unusual for a bigger dog to pull the koala off the fence and attack it. Try to house your dog in a fenced area that koalas will not visit.
  • If possible lock dogs up at night.
  • Always have your dog on lead when out on public land.
  • Keep the Koala Hospital or other wildlife agency’s 24 hour emergency number handy and call immediately if your dog attacks a koala no matter what the time.
  • Where possible wrap the koala up in a big blanket to keep warm while waiting for responders.
  • Do not be fearful you will get “into trouble” – wildlife personnel simply wish to take the koala in for treatment.

Download our Guide to learn how you can assist your local koala population.Download Guide

Download Guide

Here's how you can help!

Adopt

Adoption is a meaningful and symbolic way to contribute to the conservation of koalas. Adoption allows you to directly fund koala rescue, management of sick and injured koalas and the rehabilitation of koalas and their habitat. Learn about the koalas available for adoption to find who you connect with here!
Adopt

Donate

Making a donation contributes directly to the funding of conservation efforts of wild koalas and their habitats, providing care to sick and injured koalas and supporting research and education efforts. Donating is an easy and effective way to directly help our Koala population, a little goes a long way.
Donate

Visit

Come see us in action to find out what we’re all about! Drop into the Koala Hospital during our opening hours (8:30am to 4pm every day) to get a first-hand look at our facility, including our Koalaseum, care clinic, and shop. You can learn about our rescue and rehabilitation efforts and check out our facility visit our exhibit koalas.
Visit

Become a Volunteer

We are always on the search for new, passionate volunteers ready to help make a substantial difference in koala safety. Find out more on how you can help our koalas today.
Volunteer

Plant a Tree

The major threat to koalas are loss of habitat. A $20 donation will enable us to plant one food tree. Your donation will help nourish koalas in the future, and reduce Australia’s carbon footprint!
LET'S PLANT!

Report a Sighting

If you catch sight of a koala, complete our reporting form and include any observations to help us monitor koalas. If you observe an injury or signs of illness, call our rescue hotline.
Report Sighting