New climate change threat to tropical rainforests

The team studied 15 years of fruiting and flowering records from the Skyrail Rainforest Cableway, a 7.5km path through pristine World Heritage tropical rainforest.

“We found that liana reproductive activity increased with warmer temperatures and dry spells, suggesting a link to climate change.” said Dr Nara Vogado, the lead author of the study.

“Lianas have been found to be better adapted to drier, warmer conditions, and forest disturbance, and have advantages over old-growth trees which are adapted to undisturbed rainforests,” said Dr Vogado.

The researchers also found found that liana reproductive activity increased following El Niño events, and this was made possible through the availability of long-term ecological records.

“The persistence of research efforts across decades by SkyRail staff member Tore Linde has been instrumental in our ability to track the change in lianas,” said Assistance Professor Michael Liddell, a co-author of the study.

“We have already seen that liana abundance is increasing in intact forests in the Amazon, and this study suggests that we might see similar trends here in the Wet Tropics,” said Professor Bill Laurance, a co-author of the study, who has worked in tropical rainforests for more than 40 years.

“Increased activity and abundance of lianas can have serious impacts on tropical forests, as they parasitise and kill trees, and can impede growth of new trees.

“This can have profound impacts on the structure and function of tropical rainforests, which in turn affects the animals that depend on them as well as their ability to capture carbon from the atmosphere,” said Professor Laurance.

“Long-term studies like ours are essential for understanding the impacts of climate change on tropical rainforests and other ecosystems,” said Dr. Vogado.

“By identifying changes in leafing and reproductive activities of different species we can identify potential future changes to the composition and function of ecosystems.”

The researchers said a proliferation of lianas driven by enhanced reproductive effort under climate change could have profound impacts for tropical forests in the Australian Wet Tropics and globally.