As a bushfire continues to burn in one of Australia's most important biospheres, a local botanist worries native plants are not rejuvenating from historic blazes and says more research is required into the impacts of all fires, including prescribed burns.
Sparked by lightning, the latest bushfire has burned through 4,400 hectares in Fitzgerald River National Park on Western Australia's south coast over the past week.
At its peak, the fire reached emergency level and made national headlines on Tuesday after two pilots escaped a Boeing 737 crash while fighting the blaze.
Local botanist Gillian Craig said some species in the park, which is one of just four United Nations Educational, Scientific and Cultural Organisation (UNESCO)-listed biospheres in Australia, have not recovered from previous blazes.
"Sometimes after fire the plants that can only regenerate from seed aren't recovering. They're not coming back after fire," she said.
Hakea plants diminishing
Dr Craig said a patch of "iconic" hakea plants had greatly diminished after bushfires in 1989 and 2003.
"I was up there in the early 80s and took a photo. They were everywhere like lanterns," she said.
"When I went back a couple of years ago they were still there and looking beautiful, but probably only a third as many [as] when I first went up in the 80s."
While there is a general understanding that native bush rejuvenates after fire, Dr Craig says it is possible some plants in the park do not have enough seeds to properly replenish.
"It's unknown what is the cause of that," she said.
"Is it because the plants aren't old enough with a big enough seed bank when the fire comes through, or is it because after the fire there's a drought and the seeds do germinate but don't come back afterwards?"
Unburned bush essential
Dr Craig said more research was "urgently" needed to understand the impact of bushfires, including prescribed burns.
"We just need to monitor what happens after these fires, prescribed burns and wild fires, to see if there's a pattern, and work out how long it takes different species to regenerate," she said.
Much of the park has burnt in recent decades, including during another lightning-sparked fire last year.
Dr Craig said that made it difficult to truly understand the impacts of fire because species were not getting a long enough break between prescribed burns and bushfires.
"We need very long, unburnt vegetation to act as reference areas for other areas in the park," she said.
"It cannot be assumed that fire is good for biodiversity maintenance."
