Rare and unique flora and fauna in Western Australia's Stirling Range may never fully recover from a massive series of fires which devastated the national park, which is considered one of the world's most important biodiversity hotspots.

Key points: More than 40,000 hectares of land have been burned in bushfires in WA's Stirling Range National Park

More than 40,000 hectares of land have been burned in bushfires in WA's Stirling Range National Park The park is home to more than 1,500 species of flora, at least 87 of which are found nowhere else in the world

The park is home to more than 1,500 species of flora, at least 87 of which are found nowhere else in the world Conservationists say the landscape will take centuries to recover and needs long intervals between fires before they can produce viable seeds

Sparked by lightning, intense fires tore through more than 40,000 hectares of land in the park, about 400 kilometres south-east of Perth, between Boxing Day and the New Year.

The series of fires left almost half the rugged park scorched.

With efforts from over 200 fire crew across the week, the fire was brought to advice level without any lives or property damaged.

But there are now concerns for the park's unique flora and fauna, which has faced multiple large-scale fires in the past two decades.

Biodiversity hotspot

The south-west of Western Australia is recognised internationally as a biodiversity hotspot, largely thanks to the Stirling Range.

The National Park has more than 1,500 species of flora packed within its boundaries — more than the entire British Isles.

This joey was rescued and treated for burns, after it was lost during the Stirling Ranges bushfires 2019. ( Supplied: Ryan Pollock )

At least 87 of those species are found nowhere else in the world — including rare mainland quokkas.

Chief executive of Gondwana Link, a private conservation enterprise, Keith Bradby described the park as "one of the most precious jewels of the region" but said frequent fires in the park had put species under a lot of stress.

He said the landscape would never fully recover.

"It will be changed for decades, if not centuries," he said.

"If [there is] fire too frequently you'll be taking out plant species before they have a chance to set seed again.

"You will be favouring a few plant species, you'll totally change the flora and vegetation and you'll totally change the whole feeding pattern of wildlife — the whole food chain alters."

A photo of Bluff Knoll before the fires. Landcare experts say the biodiversity will never be the same. ( Supplied )

Mr Bradby said he was most concerned for the Montaigne thickets and the quokka population.

"It's one of the few mainland populations of quokkas left, and they were in that part of the park," he said.

"Whether they're going to rebound I can't tell.

"And the Montaigne thickets are already damaged because of dieback.

"Whether they're on a downhill trajectory or whether we've terminated it — we don't know."

Assessing the damage

Greg Mair from Parks and Wildlife Service and Wayne Green from Department of Fire and Emergency Services in front of the peak of Bluff Knoll. ( ABC News: Gianfranco Di Giovanni )

The Department of Biodiversity and Conservation (DBCA) will now begin to assess the damage at the national park.

Yesterday, Parks and Wildlife Officers started inspecting the damage on Bluff Knoll, the park's highest peak at 1,090 metres.

DBCA south coast regional manager Greg Mair said they will not know the full extent of the damage until spring, when species start to regrow.

"We haven't had the opportunity to asses apart from an aerial survey," he said.

"But we do know that among the very rare and interesting species that are in the Stirling Range National Park, a number of them have been burnt, 14 are critically endangered and there are two threatened ecological communities."

Mr Mair said similar scale fire had burned in the park in 1991, 2000 and 2018.

"The key to this is the interval between fires," he said.

"Some of these species require really long intervals before they can produce viable seed and if you have too frequent a fire that starts to reduce the seeding capacity and the reproductive capacity of the plant."

The Stirling Range National Park will remain closed indefinitely, including the popular Bluff Knoll hike, as DBCA assess damage to infrastructure and walk trails to make sure it is safe to enter.