Researcher digs deep on wetland weed

A grassy weed is impacting birdlife and wetland habitats at Kakadu National Park, according to a Charles Darwin University PhD graduand.

Research Institute for the Environment and Livelihoods' Dr James Boyden, who will receive his PhD at CDU’s graduation ceremonies on Friday, said his research suggested that more than 30 per cent of the park’s 255 sq km Magela Creek floodplain was at high risk of a para grass invasion.

Dr Boyden said the spread of para grass into wetland areas would likely impact magpie goose habitat by replacing wild rice and other native foods with the less nutritious grass.

“Para grass chokes out native vegetation and creates a blanket of monoculture,” he said.

“It can also impact on traditional fishing and bushfood collection by physically blocking access to certain wetland areas and limiting native food sources.”

Dr Boyden said the weed was a slow invader, but had rapidly increased in some park areas since it was introduced more than 70 years ago.

He said remote sensing satellite technology could assist in weed management by identifying potential hotspots for invasion before the weed became established in an area.

“Positively, para grass is a slow invader. What is concerning is its continued invasion into wetland areas in a localised way.”

Dr Boyden said park rangers were managing the weed in many critical areas of the park, and remote sensing could help to set management priorities and resource allocations.

He made his research observations by classifying wetland habitats and vegetation from ground knowledge, satellite remote sensing and historical maps, accounting for patterns of vegetation change across various wetland habitats over 24 years between 1986 and 2010.

CDU will hold its end-of-year graduation ceremonies on Friday at the Darwin Convention Centre.