Parasitic, tree-strangling vines are running rampant due to climate change: experts

The climate crisis may lead to more lianas — parasitic vines common in tropical areas around the world — along some of Australia’s iconic northern rainforests, scientists have found.

These vines are a crucial part of many rainforest ecosystems, but they can also stifle tree growth as they wrap around the forest and compete against trees for light.

If these rainforests saw a significant increase in vine abundance, it could alter the fundamental nature of the ecosystem — including their ability to store planet-warming carbon, the authors of a new paper say.

“When you have a forest that’s got a lot of vines, it typically has smaller trees, and fewer surviving trees, and it will store considerably less carbon,” Bill Laurance, an ecologist at James Cook University in Australia and one of the study authors told the Australian Associated Press.

The new study looked at vine reproduction at a rainforest in Queensland, Australia, over a fifteen-year period, with attention paid to how the climate crisis might be affecting reproduction. Results were published this month in Frontiers in Forests and Global Change.

In general, both fruiting and flowering activity in lianas increased over time — two reproductive activities that could mean more growth, the study found. Higher levels of fruiting and flowering were connected to higher temperatures, and higher levels of flowering were connected to less rain.

This part of Australia is expected to get hotter and drier at times of the year as the climate crisis continues, the study notes. The study also found more reproductive activity after El Niño events — which the authors note cause hot, dry conditions in Australia.

Las year, another study found that lianas in a Panamanian rainforest increased when there were more “disturbances” — like when storms knock down a swath of forest or a tree dies, leaving a gap.

Lianas are often more well-adapted to colonising recently disturbed areas, the new study notes. If the climate crisis were to spur more forest disturbances through things like cyclones, heatwaves or droughts, that could lead to more liana growth.

Tropical rainforests like those in Australia are important to both global biodiversity and the planet’s climate, harbouring millions of different species and storing tons and tons of carbon in soil and plants that would otherwise be warming the atmosphere.

But if liana growth were to increase with the climate crisis, the forests could suffer as more trees die. For one, you might end up with fewer resources for some local wildlife that depend on trees, the study notes.

In addition, liana-heavy ecosystems are not as efficient at long-term carbon storage as tree-heavy ecosystems, so more lianas could mean less carbon sequestered away in these forests.