New tool highlights impacts of natural disasters on waterways

A NEW biodiversity mapping tool is providing critical data on how rivers and estuaries across the region are impacted after natural disasters.

Southern Cross University lead investigator Dr Maarten De Brauwer said the data paints an important picture of the species living in and around NSW coastal tributaries.

“The data revealed the location of 68 invasive pest species in various rivers, including aquatic weeds, algae and even cane toads further south than previously thought,” he said.

“This data can show what is actually happening to our biodiversity in estuaries following disasters like floods and bushfires.

“It can inform management agencies, biosecurity responses and help the ranger network manage these complex and dynamic systems after major disasters to support species recovery.”

The major study of NSW estuaries is funded through the Riparian Stabilisation Package of the NSW Estuary Asset Protection Program.

The map covers tributaries along a 1000-kilometre stretch of coastline and uses environmental DNA.

It can detect everything from algae blooms in lakes to critically endangered species in the ocean, using a technique known as eDNA metabarcoding.

It samples many species at once by extracting DNA from water or sediment.

Dr De Brauwer’s team recently returned to sample sites following Tropical Cyclone Alfred and the March rain events to compare data.

“While the collection method is simple, the technology is incredibly sensitive and some results required some sleuthing,” he said.

“For example, we found water buffalo DNA in the Richmond River — very far from where you’d expect it.

“When we went looking, we found a horse trainer using four water buffaloes named Bob, Ben, Bill and Bruce to train horses, which explained it.”

Dr De Brauwer said Indigenous ranger groups had been important partners in the project, helping to collect samples and contributing local knowledge.

The Riparian Stabilisation Package is jointly funded by the federal and state governments under the Disaster Recovery Funding Arrangements.

Southern Cross University operates the program under its Catchments, Coasts and Communities Research Impact Cluster.