Main Club, 7 March 2025
Our speaker was Lauren Hawkins, a research scientist with the Department of Biodiversity, Conservation and Attractions (DBCA). Lauren’s speciality is ecoacoustics, which is the study of environmental sounds. It involves using these sounds to monitor ecosystem function and health, such as biodiversity, species distribution, fauna behaviour, and ecological change. She has done work in terrestrial ecosystems using microphones to record sounds, and in marine environments using hydrophones.
For example, it is easy to understand that an ecosystem disturbed by human activity may be either extra quiet or extra noisy. There is also bioacoustics, which focuses on a particular species and how that species produces and responds to sounds. For example, mulloway in the Swan River produces choruses that may be audible above water when enough individuals call together.
Sound-recording equipment to monitor ecosystems can be cost-effective, non-invasive, and can be used over a wide area. Even sounds with a pitch outside the range of human hearing, such as that of most bats and some insects (such as cicadas), can be recorded. And the hopping and digging sounds of marsupials likewise. Software and machine learning techniques can then analyse big acoustic data sets. This is a developing field. Graphs of the acoustic spectra over time in a particular area of Jarrah Forest or a Wandoo Forest, for example, can reveal a great deal about the species composition at that locality and the activity of the various species that live there. Such data can be used to find how forest areas differ by using clustering analysis. Working out the reasons for the differences can answer questions about the impacts of environmental or human-made change.
Ecoacoustics can be used in conservation. Applications include the acoustic detection of pest bird species, such as the Department of Primary Industries and Regional Development (DPIRD) starling detection program in Western Australia, the tracking of priority fauna, the detection of habitat degradation, the measurement of the progress of restoration, and Citizen Science projects.
Lauren gave us a multiple-choice “What’s making that sound?” game, which led to some interesting discussions. Many of us know the calls of local birds, but little is known about the sounds of local mammals (except whales). Apparently, Echidnas coo in courtship!
Mike Gregson