VOICES FOR THE EARTH: Counting koalas
For years there has been widespread concern about koala population decline in NSW. The black summer bushfires have made this a much more urgent concern - a matter recognised by the Legislative Council committee inquiring into koala populations and habitat in NSW.
The committee's report (Koala populations and habitat in NSW ) was released on June 30. In referring to the scale of koala loss during the fires, it stated that "without urgent government intervention to protect habitat and address all other threats, the koala will become extinct in New South Wales before 2050."
It also referred to the current estimate of 36,000 koalas in NSW as being outdated and unreliable.
Estimating koala numbers has always been difficult because they camouflage well and are difficult to locate.
A group of researchers associated with the University of Newcastle who have been experimenting with heat-detecting drones to locate koalas think that they may have a more efficient and cost-effective solution.
In an article in The Conversation (July 7) these researchers described their testing of this new technique in Port Stephens in the winter of 2019 in an area where the koala population was widely dispersed.
They stated that by searching forests on foot at night with spotlights they found on average about one koala every seven hours. When they used a thermal drone at night in these same forests, they found an average of one koala every two hours.
The search was conducted using a drone with both a thermal and a colour camera flown back and forth so that no spots were missed. When they saw a large infrared blob in the tree canopy, they paused the drone to capture GPS data and detailed images.
The next day, using the drone again, they were able to verify these night time detections and obtain very high-resolution colour images as well as thermal images.
The researchers believe this technique could be used to assess koala numbers in fire-burnt areas in coming months. And there are many other possibilities for its use in locating other threatened species in isolated refuges or difficult terrain in Australia and elsewhere.