Like many other creatures fighting for their existence, Koalas have been listed as “threatened”. According to the Australian Federal Environment and Biodiversity Protection Act, animals are considered “threatened” once their population has declined by approximately ~80%.

 

Data was collected from wildlife hospitals in South East Queensland (SEQLD) from January  1997 to December 2013 in order to investigate and evaluate the severe decline of Koala populations in the outback of eastern Australia. With over 42,257 data entries gathered in the 20,250 koalas monitored over the study period, a total of 11 aetiologies have since been identified, with chlamydiosis, motor vehicle trauma, and wasting being the most common. 

 

There seems to be no obvious prevalence of sex-based differences in the aetiologies, but it has been noted that older koalas seem to be more at risk than younger koalas.

 

The occurrence of Chlamydia-like signs has maintained above 30% across all years of the database. Chlamydia spp. can influence population dynamics, affecting koalas by increasing mortality from wasting and blindness and decreasing population recruitment through impairment of reproduction. Chlamydiosis frequently co-occurs with other aetiologies, especially wasting. However, immunodepression seems to only play an important role at a population level; when other extrinsic factors induce physiological stress, urbanization and habitat fragmentation are present.

 

Motor vehicle trauma is decreasing, but current admissions include more emaciated koalas compared to the mid-1990s. More than 25% of the original koala habitat range has been cleared, forcing them to cross major travelling routes and come into contact with cars. Though this occurrence is decreasing, older koalas are less likely to survive the injuries sustained.

 

Studies like the one presented here serve to protect vulnerable creatures like the koala. The successful preservation of a viable habitat, educating local and federal governments and introducing new management policies, and successful rehabilitation of animals in care facilities approaches the on-going problem for these animals and proposes positive outcomes.