Not all fires are equal: study finds threatened marsupials cope with ‘cool’ fires

A research team is currently on the ground reviewing images from camera traps deployed at 130 sites in four national parks in and around the World Heritage-listed Gondwana Rainforests of northern NSW: Nightcap, Tooloom, Koreelah and Gibraltar Range.

The 2019-2020 bushfire season has provided an opportunity to work with NSW National Parks and Wildlife Service, as part of its 10 year Burning Hotspots project, to build on existing knowledge to see how the threatened long-nosed potoroo, red-legged pademelon, black-striped wallaby, Parma wallaby and their predators, respond to large-scale intense wildfires.

“We have data for sites from before the wildfire so we are monitoring in fire-affected areas and areas of unburnt forest to determine the response of threatened marsupials along with predators such as dingoes, foxes and cats,” said lead researcher Darren McHugh, an ecologist and PhD candidate.

“What we have seen so far is a spread of fire intensity across our parks with some areas burnt harder than others. We know areas like Nightcap National Park were affected by the wildfires but it wasn’t catastrophic. However, the Gibraltar Range was hit hard.

“Small scale, patchy ecological burns provide macropods with unburnt refugia that they use as well as small burnt areas. It certainly will be interesting to see how our species have responded to the 2019-2020 wildfires which were very different to the NPWS prescribed burns we monitored.

“Not all fires are equal.”

In contrast to wildfires which usually occur in the warm seasons and are much larger in scale, prescribed (or ecological) burns are generally conducted in the cooler seasons and are small in scale.

The 2019-2020 wildfires burnt through approximately 5.3 million hectares in NSW (including 2.7 million hectares of National Parks) and some were the largest fires to date.

Mr McHugh has been working in the region’s national parks for the past four years, examining the response of threatened small macropods to prescribed burns and introduced pests for his PhD research thesis.

His recent study published in the journal Ecological Management and Restoration examined the response of the threatened species and their predators to prescribed burns in northern NSW, Australia.

“Our previous research has shown that these threatened species are highly dependent on complex understory habitat that conceals them from predators. Recent literature from temperate Australia suggests that prescribed burns conducted in the presence of foxes and cats can have negative consequences for medium-sized mammals and small macropods," Mr McHugh said.

“Our study found that the activity of long-nosed potoroos and red-legged pademelons in the national parks on the NSW North Coast did not change following small scale ecological burns, nor did the activity of dingoes. Although feral cats and foxes were present, they showed negligible activity therefore the threat of predators to our threatened species in the post-fire environment appeared to remain unchanged. We attribute this to sufficient unburnt refugia within our burn sites and also very low densities of foxes.

“What this means for better environmental management is that a balance of burnt and unburnt patches should be maintained within prescribed burn management zones to allow for threatened small macropod habitat refugia.”

Darren McHugh’s research has been supported by the NSW Environmental Trust’s Saving our Species (SoS) Partnership Grant.