Extract from ABC News
The red beak orchid is also known as the fire orchid because of how the species often flowers after a blaze. (iNaturalist: Felix Nicholls, Red beak orchid, CC BY-NC 4.0)
Crouched on the sandy soils of an urban bushland in Perth, ecologist Mark Brundrett points out a herd of green elephant ears.
The "ears" are a flush of fleshy little leaves, firmly attached to the ground, belonging to the red beak orchid (Pyrorchis nigricans).
The plant's Greek genus name, Pyrorchis, translates to "fire orchid". Its red and white flowers appear most often after a bushfire when its seeds can spread on the wind to new areas.
But when it goes without fire for a long time, the orchid clones itself — by making several new underground tubers from each leaf annually — with individuals known to spread out some 30 metres wide.
The red beak orchid will often just show its fleshy green leaves above ground and not flower unless there is a fire. (Flickr: Mark Brundrett, Red beak orchid, All rights reserved)
"There's a paradox in this orchid," says Dr Brundrett, an adjunct associate professor with the University of Western Austalia.
"This orchid needs fire to reproduce by seed, but it's harmed by fire when it wants to develop a large healthy colony."
So while fire makes the orchid flower, flames may also reduce the size of the plant or wipe it out completely if it is too intense or frequent.
In this particular patch of Warwick Bushland — a 63 hectare site of mixed jarrah and banksia woodland — the red beak orchids haven't been hit by a fire for three decades.
"If [the plant is] the same individual, it could be thousands of years old," Dr Brundrett says.
That contrasts with more frequently burnt parts of the small bushlands where there are smaller patches of red beak orchids with fewer tubers.
Ecologist Mark Brundrett studies the impacts of fire on WA's flowering plants like orchids. (ABC Science: Peter de Kruijff)
It's just one of the complex relationships between 17 different orchid species and fire that Dr Brundrett is studying in the small bushland.
"Some orchids are very tolerant of fire and some even benefit from it because they flower more," he says.
"But the downside is that there's more orchids that are harmed by fire than benefit from it."
The common bunny orchid (Eriochilus dilatatus subsp. multiflorus) is among 17 species being studied in Warwick Bushland. (ABC Science: Peter de Kruijff)
Orchids are just one of many Australian plant groups and species that have evolved over millions of years to adapt to fires.
But the way that fire moves in the landscape is rapidly changing, so the question is whether strategies used by flowers in the past to survive will work in the future.
The threat from fire
Large bushfires in Australia, and globally, are thought to be getting more intense. Firefighters say they're also running hotter at night than in the past.
In the past six years there have been huge fires which have torn through entire national parks and beyond in one go.
For example, the 2019–20 Black Summer bushfires burnt more than 24 million hectares of land and half the ranges of about 800 different flora species. About 150 of these species had most of their range burn.
Many of these species are resilient to fire and some even rely on it.
Pink flannel flowers spring up quickly after fires to produce seed to be stored in the soil until the next blaze. (iNaturalist: Tom Brennan, Pink flannel flower, CC BY-NC 4.0)
After Black Summer, large drifts of flannel flowers (Actinotus sp) — one of Science Week's top 10 amazing wildflowers — sprang up en masse in the Sydney region.
Pink flannel flowers (A. forsythii), which rely on smoke to trigger growth, are among a group of plants known as fire ephemerals.
They follow the "live fast, die young" motto by trying to grow quickly and generate more seed that is stored in the soil for the next fire event.
The seeds of fire ephemerals are thought to be able to last for decades, if not a century, between fires. That means that sometimes, new species are found after fires in long-unburnt areas.
But scientists are concerned about other flower species that don't get enough time to recover before the next blaze comes through.
The long slender red and yellow flowers of the Christmas Bell ( Blandfordia sp) also appeared after Black Summer in the east.
Vibrant Christmas bell flowers bloom in abundance after bushfire. (ABC Mid North Coast: Emma Siossian)
Studies of B. grandiflora at a site near Port Macquarie, show flowering peaked after the second fire season, regardless of how often fires occur.
But it takes three years for the plant to develop from seed to flower, so fires more often than this may be detrimental to the species.
Royal Botanic Gardens Victoria seed scientist Rebecca Miller says there is a delicate balance in Australian ecosystems.
"With climate change, there's a shift in terms of the frequency and intensity and probably extent and scale of fires," she says.
"Which is problematic when you're working with threatened species that might have really restricted distributions and narrow ranges."
Royal Botanic Gardens Victoria seed scientist Rebecca Miller. (Supplied: David Roberts)
When fires take out big areas in one go, they can wipe out seed stock in the soil and put pressure on flora species that might only occur in a few areas.
"Things adapted to fire, whether they're regenerating from seed or whether they're re-sprouting from lignotubers or other storage structures within the plant, need time to regrow or grow to a reproductive stage,"Dr Miller said.
Unlike the red beak orchid and the Christmas bell which have lignotubers, some Australian flowering plants, such as alpine ash and many banksia species such as the mountain banksia (Banksia canei), have no fallback strategy for fire.
Much of the distribution of the mountain banksia (Banksia canei) in Victoria was affected by the 2019–2020 bushfires. (iNaturalist: Donald Hobern CC BY 4.0)
These plants, known as obligate seeders, rely on fire and can only regenerate from seed.
"So that if the frequency is too high, then they may not have reached that point and there may not be those seeds there to support regeneration after the next fire."
Off the back of the Black Summer, scientists analysed the threat of changing fire regimes to native species for the federal government.
A bushfire wiped out Grampians National Park last year. (Supplied: Upper Beaconsfield CFA Fire Brigade )
Threatened species commissioner Fiona Fraser says climate-induced changes to fire intensity and frequency was one of the most pervasive threats to native animals and plants.
"In the period from September 2020 to February 2026, 80 bushfire affected plants have been listed as threatened under the Environment Protection and Biodiversity Conservation Act, and 39 have been uplisted — changed to a higher category of extinction risk," Dr Fraser says.
"The Australian government is investing $800 million in the recovery of threatened species and ecological communities.
"This includes action to manage fire regimes and help build species resilience."
Seed collecting is no easy affair
Dr Miller's team tries to collect seeds, many from rare or threatened Victorian species, which can be used to grow new populations or supplement existing ones after fire.
While seed from some species may last hundreds of years in storage, Dr Miller says others lose viability after 10 to 15 years.
"We need to up our research into that area to understand the frequency or how quickly we need to use our collections and the frequency with which we may need to recollect," she says.
"We've got collections from over 1,500 species now."
Seed collecting takes members of the RBGV team to far-flung parts of Victoria like this trip to harvest from a stringybark tea-tree (Gaudium jingera). (Supplied: RBGV/Jacqueline Felstead)
Collecting itself can be tricky.
"Often they're in remote and quite inaccessible areas, they produce seed erratically, the timing of that seed production might be unpredictable and vary from year to year," Dr Miller says.
"So the resourcing for collection is problematic because it does take multiple visits for many of these species."
Fruits of a dune fan-flower (Scaevola calendulacea) collected by the RBGV. (Supplied: RBGV/Andre Messina)
Dr Miller says inevitably, and unfortunately, there is picking and choosing when it comes to how the team prioritises species for collecting.
But there are a lot of significant successes.
One of the current programs at the RBGV, funded by the Victorian government, targets conservation for 24 species, including the rare rosella spider orchid.
"For eight of them, we're about to translocate populations and establish new populations, essentially, in the world for those," Dr Miller says.
"So that's come from seed collecting and germination trials, genetic research into the populations, extensive surveys of the populations, and identifying pollinators so that we know that we're establishing populations in areas where the pollinators exist."
What else can be done?
More baseline research is essential to preserve flower species.
Dr Brundrett says monitoring is necessary for adaptive approaches to managing threats like fire.
"But we need that for everything, we need it for the birds and the animals and the native plants," he said.
He also says we need to know more about other climate factors for species like orchids, like rainfall.
A hare orchid (Leporella fimbriata) growing in a long unburnt area of Warwick Bushland. (ABC Science: Peter de Kruijff)
"The growing seasons [in south west WA] are shortening from both ends," Dr Brundrett says.
"I think we should be setting up what I call orchid climate observatories where anyone can just observe orchids in a particular area and … what that tells you is basically what's happening."
And he has one other suggestion.
"Ironically, possibly the way to protect them [orchids] is to do some small fuel reduction burns around them."
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