In late 2008 a pilot study of koalas was undertaken in a new residential development of South East Queensland (SEQ). The development, named Coomera Waters, is located in the rapidly expanding northern Gold Coast suburb of Coomera – an area that is also home to a substantial koala population.

 The pilot study was coordinated by Dr Robbie Wilson, Dr William Ellis and Dr Sean FitzGibbon and formed the basis of a short research project for Master of Science student Ms Maren Dammann.

Despite the iconic status of koalas and their listing as Vulnerable wildlife in SEQ, very little is known about how they utilise urban landscapes, where there are many threats to their survival (e.g. dogs, cars, habitat loss). Koalas seem to be relatively resilient animals that can inhabit noisy, heavily disturbed environments provided there are sufficient food/shelter resources and threats to their survival are not too high. But empirical evidence of how to ensure their survival is sadly lacking and desperately required.

The Coomera Waters development was designed with consideration for the natural environment and wildlife inhabiting it. The estate has retained numerous patches of bushland of varying sizes, some of which are linked through vegetated corridors. Habitat surveys revealed the presence of a high density koala population spread across several bush patches in Coomera Waters. But there is very little empirical data that examines how koalas utilise such patches or the extent to which they move between such patches (which requires them to traverse the relatively hostile urban matrix that surrounds each ‘island’ patch).

The pilot study provided a preliminary examination of koala movement in the urban landscape of Coomera Waters. The movements of six koalas were examined in detail through the use of latest-technology GPS collars, which log their position every two hours (Figure 1).

After 3 – 4 months the six koalas were recaptured and the collars removed so that the logged movement data could be downloaded. The data were then plotted on an aerial image of the residential estate to examine the extent of their movements (Figure 2; each colour represents a different koala). The plotted data revealed several interesting aspects of the behavioural ecology of the collared koalas.

All of the koalas were found to occupy very small home ranges (0.4 – 2ha). Two of the male koalas (yellow & purple) had closely overlapping home ranges and both koalas were recorded to move through residential properties to access bushland on the other side of these housing blocks (see ^1. in Figure 2). One of these male koalas (purple) and a female (green) were regularly recorded crossing suburban streets, suggesting their home range was distributed in bushland on either side of these streets and that they were able to avoid collisions with vehicles during the study (see ^2. in Figure 2).

Two of the collared koalas (orange and green) were found to utilise a thin vegetated corridor that connects two larger bushland areas, suggesting that the characteristics of the corridor are suitable to facilitate koala dispersal (see ^3. in Figure 2). Another female (blue) was regularly recorded utilising trees that were retained in the backyard of residential properties adjacent to the bushland where majority of its home range occurred. The sixth animal (female; pink) was never recorded to leave the small isolated patch it was first captured in but it used the entire patch.

It is possible that this female was isolated in this patch when urban development of the area was commenced. Alternatively, the requirements of this female may be being met in this small patch, as male koalas may seek her out for breeding purposes and so she may have no need to move from the patch.

As this short summary suggests, the pilot study of koalas at Coomera Waters has raised more questions than it has answered. While it revealed interesting aspects of the species behavioural ecology, further research is required to determine the longer-term movement patterns of the resident koalas, and to examine the breeding patterns, genetic flow and survivorship of koalas in this urbanised landscape.

In addition, it is important to determine those features of patches that facilitate the survival of koalas in urban landscapes. For example, is there a minimum patch size requirement to ensure the survival of koalas, or is it more important that threats within the urban matrix between patches are low (e.g. few large dogs, or low traffic speeds/flows). This information is crucial to ensure the effective conservation and management of the rapidly declining koala populations across SEQ.

Additional funding is being sought to conduct a more detailed examination of the reproductive biology, genetic composition and behavioural ecology of koalas at the Coomera Waters estate and other urban areas of SEQ.