Planned Bushfires Can Reduce Weeds With Only Limited Impacts On Threatened Marsupial Species Provided


They are kept small enough to leave places for the animals to find refuge from predators, new research has found.

Scientists from the Southern Cross University used remote cameras to track the response to prescribed burns in parts of the Gondwana World Heritage Area in northern NSW. Of particular interest was how the endangered black-striped wallaby and the vulnerable-listed long-nosed potoroo and red-legged pademelon would respond.

The study, published recently in the Ecological Management and Restoration journal, examined wildlife in two sites in the Richmond Range and Tooloom national parks before and after controlled burns.

The work is part of a 10-year Burning Hotspots program with the National Parks and Wildlife Service and the Environmental Trust to cut the coverage of lantana weed and improve habitat for threatened macropods.

Darren McHugh, the lead author of the paper, said researchers had hypothesised predator activity would increase once the lantana cover was reduced.

However, “dingo activity within both burn blocks was very low and activity of foxes and cats was negligible,” the research found.

“It was a null result – it’s good in a way,” Mr McHugh, a PhD student and biology tutor at the Southern Cross University, said. “The small-scale fires didn’t appear to change the [marsupials’] behaviour.”

The fires have to be kept patchy not least because the home ranges of the potoroo and pademelon are less than 6 hectares, while the wallabies range up to 91 hectares, the paper said.

Environment Minister Matt Kean said that while the study suggests cool, small-scale prescribed burns don’t reduce the numbers of macropods “not all fires are equal”.

Last season’s huge bushfires burnt more than 2600 hectares of wet sclerophyll and emergent forest in the Richmond River World Heritage Area, the worst seen in that part of NSW since 1968.

“These fires were much larger and more intense than the prescribed burns that have been studied to date,” Mr Kean said, adding the governments had responded by adding 90 monitor sites to examine the impacts.

One scientist not involved in the study also cautioned against extending the findings from prescribed burns to wildfires. Similarly, while remote cameras can provide useful data, the results were too short term to reveal longer term trends and don’t provide insights into the abundance of the studied species.

Another researcher, Phil Zylstra, an adjunct associate professor at Curtin University, noted the paper contained qualified conclusions.

“After burning at a very small scale, they said that their burn may not have caused damage to the threatened species,” Professor Zylstra said. “Then, without waiting to see whether lantana would now increase as expected due to their burn, they said that more burning should really be looked into.”

Mr McHugh said lantana was “a tangent” to the research.

Bushfires, “The historic absence of disturbance such as fire (frequency) may allow lantana to persist and invade,” he said. “Even if frequent fire doesn’t completely eliminate lantana, it may suppress it enough to allow grasses and pioneer native species to develop and persist.”

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