A recent survey of constructed wetlands in Far North Queensland has shown the vital benefits they can provide to many native Australian avian and aquatic species.
In the 1990s cane farmers were enabled by the Sugar Industry Infrastructure Package to build a series of constructed wetlands on the floodplains of the Tully River.
Surveys of these wetlands carried out under a project supported by the Tropical Water Quality Hub of the Australian Government’s National Environment Science Program shows many fish species utilise these built wetlands, including species that have a diadromous ecology, (requiring access to both freshwater and saltwater to complete lifecycle stages) like barramundi, (Lates calcarifer).
Landholders also benefited by using excavated soil to raise the level of their fields, protecting themselves from crop losses during flood events.
Farmer Garth Pernase, operating near the Johnstone River, said he had experienced multiple benefits from constructing a wetland on his cane property in 2010.
“We’ve seen a lot of native species – both fish and birds – in the wetland since we built it,” he said.
“There’s lots of other side benefits as well – the wetland is aesthetically pleasing, it’s nice to visit and look at.
“I’ve also been able to raise a portion of other growing land above flood level and in that area the wetland’s also been great for drainage, this had been fairly marginal cane land where a lot of crop was being lost to grass.”
A recent publication containing these results on Great Barrier Reef coastal ecosystems outlines that restoring cultural, biodiversity and water quality values is a priority in the Great Barrier Reef catchments, an important action in achieving the government’s targets set in the Reef 2050 Plan.
Coastal wetlands provide critical habitat for aquatic flora and fauna species, as well as cultural and economic value for local communities in Australia. The ability for wetlands to continue providing these ecosystem services in the future is threatened by continued pressures from agriculture, overfishing, hunting, recreational use, water extraction and pollution of water.
The final report of the NESP TWQ Hub project led by Dr Nathan Waltham will be available in December 2020 and inform future wetland construction designs planned over low-lying coastal areas in the Great Barrier Reef catchment.