After the ash: ‘It will take decades to grow back’

As ecologist Dave Maynard walked across the ash laden soil of the The Main Ridge Track within Tathra Wildlife Reserve on Sunday, a lone eastern yellow robin sat resting on a blackened tree branch.

“I was walking through thinking there’s nothing there, there was no sound, there was nothing moving. It was weird,” the principal ecologist with NGH Environmental said.

“It would be hard to know the mortality levels, but it would have to be high.”

The fast moving fire consumed over 1000 hectares of bush on March 18, as strong west-north-westerly winds blew for over five hours, spreading fire from trunk to trunk, leaving behind a sea of scorched brown leaves.

Mr Maynard said it would take fauna “many, many years” to recover from what he described as a “high intensity, midstorey fire”, with recovery time heavily dependent on climate and rainfall levels.

The March 18 fire moved quickly towards Tathra. Picture: Google Earth

The March 18 fire moved quickly towards Tathra. Picture: Google Earth

“If we get some decent rain, then watch it go, because there is a really fertile ash bed,” he said.

“We need rain to trigger the event and then more to sustain the growth of the plants, although too much rain may cause erosion.”

With predictions of less rain and more extreme weather events, the future is uncertain, he said.

What is certain is plants will grow back in differing stages, he said, as sprouts begin to appear on eucalyptus trees, shoots from the roots of large acacias, and Banksia seeds become stimulated by the fire.

“It is really important in Australia, because if you have an area that hasn’t had a fire in a long time, it helps the growth,” he said.

“A lot of the old Banksias are dead, it will take decades to grow back, and they are a very important foraging plant for animals.”

Picture: Dave Maynard

Picture: Dave Maynard

The fire would have destroyed the homes and food sources of many animals, he said.

“Because it was a high intensity fire, there will be hollow-dependent fauna like possums that wouldn’t have survived,” he said.

Mr Maynard said birds would have dispersed “very early”, and kangaroos were seen “bounding” through town, as many species sought safety in the direction of Bournda National Park.

The health of some populations may be at risk of dropping due to the increased competition for resources such as food, he said.

“One species impacted greatly will be the glossy black cockatoo, which feeds exclusively on the black sheoaks, and is very particular about what it eats,” Mr Maynard said.

“Their feed trees will be gone, putting pressure on the surrounding areas which will now have a larger population.

Regrowth will occur in stages, says local ecologist Dave Maynard. Picture: Dave Maynard

Regrowth will occur in stages, says local ecologist Dave Maynard. Picture: Dave Maynard

“Although they are lucky there is lots of bush around.”

Slower moving animals, including reptiles and marsupials like bandicoots, would have been hit hard by the fire, he said.

“It’s hard to know the mortality levels, but it would be high, and eggs may have been left behind,” Mr Maynard said.

There is also a flip side to fire, with large tree limbs falling to the ground “important” for creating livable hollows for future generations of arboreal, or tree-living, mammals.

During his walk through the burnt landscape, Mr Maynard said one animal appeared to be thriving, despite the destruction around them – ants.

Leaves were left scorched by the fast moving fire. Picture: Dave Maynard

Leaves were left scorched by the fast moving fire. Picture: Dave Maynard

“If you take a look there’s heaps of new ant mounds around,” he said.

“Because the fire was hot and moving fast, the ground wasn’t heating up as much as it could have, which means ground dwelling larvae like cicadas may have survived.

“Insects are very dependent on plants for their life cycle.”

Mr Maynard said a second fire in quick succession may see the area’s “seed bank” depleted if new seedlings do not reach maturity.

“Future fire frequency and intensity will be important for that community,” he said.

“Now it’s a matter of just sitting back and waiting.”

Mr Maynard encouraged people to become citizen scientists, and upload photographs of animals they see in the fire zone to websites such as the CSIRO’s biodiversity database, The Atlas of Living Australia.

“It will be interesting to see what comes back,” Mr Maynard said.

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