Mountain rescue

“These plants, which rely on the cool tropical mountaintops more than 1000 metres above sea level, are losing their habitat,” said Professor Darren Crayn, Director of the Australian Tropical Herbarium at James Cook University in Cairns.

“Until now, the remote and rugged nature of these sites has helped shelter them from the usual human impacts,” Professor Crayn said.

“Climate modelling now predicts drastic habitat loss from the highlands within as little as 15 years, with droughts being longer, hotter, drier and more frequent.

“Lowland species might be able to migrate to favourable niches elsewhere, but these mountaintop species may already be at their limits. They can’t go up as the climate warms. They’re running out of space and they’re running out of time.”

The five-year project, led by Professor Crayn, is funded by a $500,000 grant from the Ian Potter Foundation and $50,000 from the Wet Tropics Management Authority (WTMA).

The species to be rescued range from tiny orchids to huge trees and include Australia’s only native rhododendrons.

“These mountaintop ecosystems are unique, not just nationally but globally,” WTMA Principal Scientist Dr Sandra Abell said.

“Many of the species, both plants and animals, are found nowhere else on Earth, which is one of the reasons the Wet Tropics were inscribed on the World Heritage register in 1988.

“The best conservation outcome is to protect species in their original habitat,” Dr Abell said. “But the modelling tells us we’re unlikely to have that option, so this is Plan B: act now to secure the most diverse ‘captive’ collection we can.”

Scientists and Western Yalanji Traditional Owners and rangers will first meet to exchange knowledge on contemporary and traditional science related to climate change and mountaintop plants at Mt Lewis, near Mossman in the Wet Tropics World Heritage Area.

“These plants and these landscapes are part of Western Yalanji country,” said Western Yalanji Traditional Owner Johnny Murison. “We’re glad to be working with scientists to help preserve them. To know country from a western science point of view adds a fascinating depth to our traditional knowledge.”

With permission and involvement of Western Yalanji Elders and rangers, the team will gather plant material from Mt Lewis for propagation at the Australian National Botanic Gardens and the Royal Botanic Gardens Cranbourne.

Plants from Mt Lewis will then be distributed to subtropical and cool-climate botanic gardens in Queensland, New South Wales and Victoria, where they will be grown in conservation collections and used in research and education.

“The aim is to secure the most severely threatened tropical mountaintop species in well managed, living collections with micro-climates as close as possible to their original habitat,” Professor Crayn said.

Once the plants are safe in cultivation, experimental work will assess the physical limitations of these species. “This information will be used to improve models of how wild communities will react to climate change, as well as assessing their ability to acclimate,” JCU plant physiologist Dr Alex Cheesman said.

“The research will inform management of living collections and will also help scientists predict what will happen to the species diversity of the Australian wet tropics in the coming decades.”

The rescue mission is guided by an earlier program of on-ground surveys funded by the Ian Potter Foundation and the Australian Rhododendron Society’s Victorian branch.

Thanks to more botanists spending more time on these peaks and plateaus in and above the clouds, these surveys saw new species discovered and others identified in new locations. Some plants last seen many decades ago were found anew.

“The surveys gave us much better data to feed into the models, but the predicted outcome remains pretty awful,” Professor Crayn said. “The revised models predict severe to catastrophic impacts on almost all of the approximately 70 plant species that are restricted to mountaintop habitat in Australia’s Wet Tropics.”

Rather than the usual species-by-species approach to conservation, this joint effort aims to conserve many species from a unique biome.

Dr Lydia Guja, Seed Biologist, Australian National Botanic Gardens, said the job of ensuring the survival of these tropical seeds and plants remained a challenge.

“There hasn’t been a lot of research on how to keep the seeds of these species alive in conservation,” Dr Guja said. “Due to their origins high in the mountains, the seeds may not survive the processes of drying and freezing that are typically used in seed banking. We’ll be working with scientists from the Royal Botanic Gardens Sydney’s PlantBank to develop new conservation techniques.

“Once we’ve found ways to conserve these seeds, we’ll look at germination requirements to better understand what impact climate change might have on their germination. If we can understand the capacity of these seeds and plants to germinate and grow under a broad range of conditions we will know what we need to do to grow back-up plants in new sites across botanic gardens for future generations.”

Artist Donna Davis will creatively document the rescue mission, visiting the mountaintops as well as the propagation facilities and the botanic gardens where the plants will be grown in conservation collections.

“Seeing these rare plants in their spectacular home above the clouds will provide inspiration and data to create a body of work that explores their plight with reference to the complex issues of climate change and species displacement,” she said.

The rescue mission is a collaboration between the Australian Tropical Herbarium, the Australian National Botanic Gardens, Western Yalanji Traditional Owners, the Wet Tropics Management Authority, the Royal Botanic Gardens Sydney, the Royal Botanic Gardens Victoria, the Dandenong Ranges Botanic Garden, the Brisbane Botanic Gardens and the Cairns Botanic Gardens.