More than half of Tasmania's largest wetland system in kanamaluka / the Tamar River has vanished since European settlement, new research from the University of Tasmania has revealed.
The study, published in Springer Nature Estuaries and Coasts and presented at the Tamar Forum on 23 October, shows that 1,157 hectares of wetlands in the Tamar estuary have been lost since colonisation - a 52 per cent decline from 2,231 hectares to just 1,074 today. The pattern mirrors a national story, with some of Australia's urban estuaries losing more than 70 per cent of their wetlands over the same period.
The Tamar wetlands once formed a natural buffer between land and sea. During Tasmania's 2016 floods, which caused almost $180 million in damage, many of the hardest-hit areas were once wetlands that had absorbed floodwaters and filtered sediment before development claimed them.
The study, commissioned by the Tamar Estuary and Esk Rivers (TEER) Program , was undertaken by a team of researchers from the School of Geography, Planning, and Spatial Sciences, led by Joshua Briggs and wetland ecologist Dr Vishnu Prahalad.
"Every hectare lost represents countless native species that no longer have habitat, natural flood protection that has been removed, and carbon storage capacity that has been compromised," said Dr Prahalad.
To chart how the estuary has changed, researchers turned to sketches, early survey maps, and environmental records, comparing them with Tasmania's first aerial photographs from the 1940s. The result is what Dr Prahalad describes as a "time machine" of the landscape before European interference.
"The scale of loss is staggering," he said.
Once home to Tasmania's largest tidal wetlands, the Tamar estuary supported vast populations of fish, waterbirds and migratory species travelling from as far away as Siberia and Alaska. The study, published in Estuaries and Coasts, provides the first detailed record of how this ecosystem has changed since colonisation.
Working with nature
"Wetlands are like the kidneys of our waterways," Dr Prahalad said. "They filter pollutants, store floodwaters and provide habitat."
The research also highlights solutions. In California's Napa Valley, authorities opted to restore wetlands rather than build flood barriers, gaining both natural flood protection and thriving tourism and recreation spaces.
"This research provides a scientific foundation to identify where restoration could be targeted and where protection could be strengthened to support river health," Dr Prahalad said.
Next steps for the Tamar
A trial wetland restoration project is now underway on the North Esk River. If successful, it could serve as a model for similar work across the Tamar and other catchments.
"Launceston has a unique opportunity to lead in wetland restoration and become the wetland capital of Australia," Dr Prahalad said. "We now have a clear picture of where the wetlands used to be. The question is whether there is enough community and political support to bring them back."
The study was published in Springer NatureEstuaries and Coasts and can be read here .
