Environmental water has been delivered to wetlands in the Goulburn Broken catchment since 2008. This water is set aside by the Government to assist with the rejuvenation, improvement and maintenance of river, wetland and floodplain systems, and has targeted nine wetlands within the Goulburn Broken catchment. To monitor wetland response to these watering events, acoustic recorders are placed in wetlands usually before the delivery of environmental water to record the change in response at these sites as water moves across the landscape, ponds and eventually draws down.
Moodie Swamp, a 180ha cane-grass freshwater marsh and significant Brolga breeding site, received an environmental water delivery in 2021. For the first time, a 24/7 ‘Solar Bar’™ acoustic recorder was placed on site to record changes in wetland biological activity (biophony) as the site became wet. Recording continued non-stop for 12 months with acoustic files being broken up into 12-hour components. Due to prolonged wet weather, the swamp has not dried out over the past 12 months, so a comparison of wet and dry cycles has not yet occurred.
Preliminary results show a major increase in biological activity during water delivery and ponding. As the swamp water level drew down so did the intensity of biological activity as shown in the spectral analysis. Other factors such as wind and rain also influenced biological activity at the swamp, for example call activity from birds reduced during high wind events.
The use of continuous recording made possible by deployment of the Solar BarTM enables us to gain a better understanding of ecological responses to environmental water delivery and other environmental drivers with minimal human-induced disturbance of the site, and with much less time and effort.