Over the past three years, DPI forest scientists have undertaken a large-scale study on the current status and response of koalas to timber harvesting in the north-east forests of NSW. Koalas are surprisingly difficult to survey due to their low densities and cryptic nature, especially in tall remote forests. Surveys were focused on forests of the hinterland, ranges and tablelands of North East NSW, rather than the coastal strip where urbanisation is the main threat to koala populations.
SongMeters were deployed at nearly 200 sites over 7-14 nights to record male bellows over three breeding seasons (>14,500 hours of recording). The project relied on cutting-edge software developed by the Queensland University of Technology to automate the call detection process from thousands of hours of recordings.
Results showed that, on average, 65 per cent of survey sites (the small zone surrounding each SongMeter) were occupied by at least one koala, which was much higher than expected based on previous surveys using alternative methods. We found that occupancy was influenced by elevation, cover of important browse trees, site productivity and extent of wildfire in the last 10 years. Occupancy was not influenced by timber harvesting intensity, time since harvesting, land tenure, landscape extent of harvesting or old growth forest extent.
Extrapolation of occupancy across modelled habitat indicates that the hinterland forests of north-east NSW support a widespread, though naturally low density koala population that is considerably larger than previously estimated.
A paper detailing the results of this study will be released in the coming months.
Predictive models that map species distributions are a useful management tool for guiding and informing on-ground management of threatened species. Forest scientists at DPI have developed a model for the koala (Phascolarctos cinereus) in North East NSW. The model is used by the Environmental Protection Authority to predict where areas of differing habitat quality for koalas are likely to occur.
The focus was to help guide decisions on timber harvesting in forests by identifying likely koala habitat. Ultimately, this could lead to better on-ground implementation of koala management for public state forests and private forestry areas.