Macrobenthic species traits and ecological functioning in an estuary recovering from environmental stress

Reduced freshwater flows and severe drought conditions in the Murray River in the 2000s created multiple stressors along the entire length of the system. The Murray River flows into the Coorong lagoon and Murray Mouth estuary,... [ view full abstract ]

Reduced freshwater flows and severe drought conditions in the Murray River in the 2000s created multiple stressors along the entire length of the system. The Murray River flows into the Coorong lagoon and Murray Mouth estuary, which is connected to the Southern Ocean. In drought years, reduced freshwater flushing into the estuary and lagoon dramatically changed the environmental conditions from estuarine to hypersaline. There were large concerns for the overwintering, migrating birds, and commercially and recreationally important fish in the Coorong during the drought period. In 2010, a flood event occurred followed by continuous freshwater release over the barrages, which provided much needed flushing and potential for ecosystem recovery. Benthic macroinvertebrates were monitored throughout the drought and water release period as they are an important food resource for birds and fish. Biological trait analysis of key macroinvertebrate species, considering aspects of their life history, feeding, sediment mediated interactions and other ecological functions, identified processes through the recovery time. Macroinvertebrate species traits were a useful tool for better understanding of ecosystem functions throughout the recovery period, rather than just standard monitoring of macroinvertebrates. More importantly, the information obtained can inform on resilience and ecosystem functioning of the Coorong under future climate scenarios.