Habitat diversity enriches waterbird community at Bolivar Wastewater Treatment Plant in South Australia

The wastewater treatment plant at Bolivar in South Australia contains three groups of ponds which provide different managed habitats. Ponds 1, 2 and 3 contain a constant level of water of >1 metre in depth throughout the year, whereas in Ponds 4, 5 and 6 the water level is reduced each year with the result that the ponds become largely dry for several weeks from late summer. The third group of eight ponds, the sludge lagoons, are anaerobic and each year two or three of these ponds gradually dry out. In this study, we compared the abundance of the various species of waterbirds on these three groups of ponds throughout the period from September 2021 until December 2023. We found major differences in abundance of birds between the three groups. Most of the waders, together with Black Swan Cygnus atratus, Hardhead Aythya australis and Eurasian Coot Fulica atra, were largely present on Ponds 4–6, whereas Blue-billed Duck Oxyura australis, dabbling ducks, and three species of cormorants (Phalacrocoracidae) tended to be more abundant on Ponds 1–3, with the sludge lagoons generally having mainly Grey Teal Anas gracilis.