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.
A new koala tracking project is underway in north-east forests of NSW on the mid north-coast.
The project will use GPS collars on koalas to track their movements throughout the forest which will enable DPI researchers to look at the effectiveness of koala protections in State forests and relative use of young regenerating eucalypts after harvesting compared to mature forest.
The first Koala collared in the project has been tracked over the past two months and is beginning to provide better information on what tree species and sizes offer important browse as well as other aspects of habitat use like use of ridges vs gullies.
The DPI Forest Science research is partnered with the Port Macquarie Koala Hospital and Forestry Corporation.
The findings of the research will be considered by the Natural Resources Commission who is independently commissioning and overseeing other research projects investigating how koalas respond to regeneration harvesting on state forests as part of the NSW Koala Strategy.