Amidst the remote and rugged mountains that trace Australia’s eastern coastline lies one of the ecological wonders of the world: A patchwork of temperate rainforests that trace their roots to the ancient supercontinent of Gondwana.
The Gondwanan rainforests are a living time capsule; home to ancient conifers that sauropods likely grazed on during the Jurassic Period and flowering plants that offer a window into Earth’s botanical evolution during the Cretaceous. This primeval landscape hosts an astounding array of animals, too, including rare, endemic frogs and marsupials, and songbirds whose dawn choruses are an acoustic window into deep time.
The Gondwanan forests have survived a continental breakup and a planetary mass extinction event. Now, they’re being tested by humanity.
More than 80 percent of the Gondwana Rainforest World Heritage Area lies within New South Wales, the eastern Australian state that’s been hardest hit by this year’s devastating bushfires. Of it, some 54 percent—a little over 400,000 acres of land—has burned in recent months, in some cases quite severely, the New South Wales environmental department quietly reported last week. The Gondwana world heritage sites in Queensland haven’t fared much better: a little under half of their area has been affected by the fires, said Scott Buchanan, executive director of Queensland’s Wet Tropics Management Authority, which oversees tropical rainforests further north.
“These are the sort of things we just don’t expect,” Buchanan said.
Some of the most severe burning occurred within fire-adapted eucalyptus stands, said Mark Graham, an ecologist with the Nature Conservation Council of New South Wales. But with Australia coming off its hottest and driest year on record, many areas of permanently wet rainforest dried out and caught fire too.
“We’re in historically unprecedented conditions,” Graham said. “And what that means is that areas of rainforest that are rarely if ever able to be burned have been burning extensively.”
Indeed, across all of New South Wales, including the Gondwana world heritage sites and elsewhere, fires have impacted over 700,000 acres of rainforest, or 35 percent of the state’s total rainforest land, according to the environment department.
Scientists won’t be able to fully assess the damage until after the flames are completely doused. While rain over the past week brought relief across much of eastern Australia, there are still some fires burning, and fire season isn’t over. But preliminary data released by the New South Wales Rural Fire Service suggests that parts of the Gondwana rainforest world heritage complex, including Oxley Wild Rivers National Park, and Gibraltar Range National Park experienced significant and widespread damage.
Graham has personally documented damage in the Gondwana rainforests of the Mount Hyland Nature Reserve and New England National Park, the latter of which has a border just a few miles from his house. Fires in New England National Park, he said, tore through one of the remaining strongholds of Antarctic beech, dropping charred leaves of the ancient temperate rainforest tree onto his front yard.
Further north, there’s been devastation within Nightcap National Park, including severe burning within the world’s last remaining stand of nightcap oak, a relic tree from the early evolution of flowering plants that has survived tens of millions of years. Unlike the Gondwana-era Wollemi pine trees, which made it through the fires thanks to a widely publicized rescue effort, the fate of the nightcap oak has attracted little notice.
These forests contain more than ancient trees: They’re hubs of plant and animal biodiversity carried through from Gondwana. And it’s likely that diversity has taken a serious hit.
On Monday, Australia’s environment and energy department released an initial list of threatened plants and animals across the country whose habitat has been affected by the bushfires. The list, which covers 327 species, includes over a dozen animals native to the Gondwanan rainforests. Up to half of the habitat of the endangered giant barred frog—which dwells within the nightcap oak grove, among other places—has been impacted by fire. Ditto for the brush-tailed rock-wallaby and the long-nosed potoroo, two vulnerable marsupials. The endangered rufous scrub-bird and Hastings river mouse, meanwhile, might have lost up to 80 percent of their habitat.
Graham warned that there could be species that weren’t previously considered threatened but are now at risk. The Gondwana forests were designated world heritage sites, in part, because they support an astounding diversity of ancient songbird lineages. While many of these species were previously regarded as secure, some strongholds “have burnt out so extensively [they] may now actually be much less secure,” he said.
Part of the reason rainforest fires are so unnerving for ecologists is because these are ecosystems where plants and animals typically escape the flames. “For wildlife management, these are places normally seen as a refuge,” said Buchanan of Queensland’s Wet Tropics Management Authority. “The wildlife will run out of the drier forest into the rainforest.”
A key concern for Buchanan and others is that this rainy refuge will become more flammable as climate change pushes many parts of Australia into a hotter, drier state. Just as rising temperatures are forcing some tropical rainforest species, like the white lemuroid ringtail possum, to migrate uphill, ever-encroaching flames could shrink the safe havens available for plants and animals that are already highly restricted.
"Given what humanity is doing to the global climate, we may well be facing an ongoing degradation and reduction of these Gondwana reserves"
Scientists are also concerned about the ability of these ancient rainforests to regenerate in the wake of fires they’re not adapted to handle. As Graham put it, the Gondwana rainforests are already “islands in the sky,” peppering mountaintops and surrounded by flammable eucalyptus forests. If fire seasons continue to worsen, Buchanan said, the eucalyptus trees could gain a competitive advantage and start permanently edging out their neighbors.
“The real issue is, even places that have retained core areas [of untouched rainforest], the margins have been impacted, and the areas that buffered them from fire have taken such a massive hit that these core Gondwanan areas may continue to be eroded through fire and drought,” Graham said.
There are Gondwanan rainforests that, mercifully, seem to have escaped the flames. These include the core of Washpool National Park, the largest rainforest wilderness area in New South Wales, and several parks to the northeast near the Queensland border. These areas need to be protected at all costs, Graham said, as they represent refuge from which the severely burned areas might, perhaps, be repopulated.
At the same time, there may only be so much people can do to preserve and restore these forests if climate change continues to worsen.
“Given what humanity is doing to the global climate, we may well be facing an ongoing degradation and reduction of these Gondwana reserves,” Graham said.