Climate change has winners and losers. In tropical forests, woody vines known as lianas are winners. The vines snake up towering trees towards the sky—and their leaves compete with tree leaves for light. Researchers at the Smithsonian Tropical Research Institute’s (STRI) Barro Colorado Island Research Station in Panama discovered the world’s record-breaking liana, and challenge others to find a bigger one.

More than two feet in diameter (635mm) this enormous vine discovered by research assistant, Biancolini Castro on March 9, 2023, belongs to a species Panamanians call “monkey comb” for its large, spiny seed pods. Scientists call it Amphilophium crucigerum.

“We’re challenging biologists everywhere to find a bigger liana,” said Stefan Schnitzer, professor at Marquette University and research associate at the STRI in Panama who leads this research team, “There are big lianas out there, but biologists usually only measure the trees. We’re urging them to measure the lianas, too.”

Lianas are taking over the tropical forests in the Americas, just as the vines in the Grimm’s fairytale—Sleeping Beauty—took over her kingdom.  In fact, trees may be losing out to vines in forests at a global scale. Vines are favored by forest disturbances like logging, road building, agriculture, mining, and other human activities according to a recent study co-authored by STRI staff scientist, S. Joseph Wright. Wright’s research manager, Osvaldo Calderon, has collected and identified leaves that fall into mesh leaf traps on Barro Colorado Island every week for many years. They showed a 50 percent increase in lianas on Barro Colorado between 1986 and 2002.

Schnitzer and his field team, led by Seberino Valdéz, also showed that on Barro Colorado Island, a protected area, natural disturbances like tree falls and lightning strikes create favorable conditions for lianas.

Vines compete with trees and may reduce the amount of carbon dioxide they store, frustrating efforts to slow climate change by conserving and planting tropical forests.

Climate change results in more violent storms and winds, and as people continue to log existing trees, habitat fragmentation and climate change interact, both in Panama, and in the Amazon. As people divide up the forest into smaller and smaller areas, climate change effects are felt more strongly.

“There’s little doubt that such environmental synergisms are on the rise globally. It’s like a one-two punch for already vulnerable tropical forests,” said Schnitzer.

Finding the world’s biggest known liana was the icing on the cake in a study to find out if size matters, and it does. Schnitzer’s group showed that the liana species that can reach large maximum sizes have slower population turnover rates, and the species that never produce large stems have much faster population turnover rates. That is, small statured liana species grow and die faster than large statured liana species, although even large lianas grow and die faster than most tree species.

In the fairy tale, only when Prince Charming kissed princess Aurora did the vines wither away, and the kingdom awake. It is unlikely that a Prince Charming will come to the rescue of tropical forests, but understanding more about lianas will certainly inform their conservation and management.

Some references:

Schnitzer, Stefan, DeFIlippis, David, Aguilar, Antonio, Bernal, Boris, Pérez, Salome, Valdés, Abelino, Valdés, Seberino, Bernal, Fidedigna, Mendoza, Adrián, Castro, Biancolini, Garcia‐Leon, Maria. 2023. Maximum stem diameter predicts liana population demography. Ecology vol 104, DOI: 10.1002/ecy.4163

Coppieters, K., Verbeeck, H., Visser, M., Schnitzer, S., and Meunier, F.: Lianas buffer tropical forest understories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19177, https://doi.org/10.5194/egusphere-egu24-19177, 2024.

Hall, Susan Laurance, William F Laurance, Susan G Letcher, Wenyao Liu, Martin JP Sullivan, S Joseph Wright, Chunming Yuan, Andrew R Marshall. 2023. Global dominance of lianas over trees is driven by forest disturbance, climate and topography. Global Change Biology DOI: 10.1111/gcb.17140

Stefan A Schnitzer, David M. DeFilippis, Marco Visser, Sergio Estrada-Villegas, Rigoberto Rivera-Camaña, Boris Bernal, Salomé Peréz, Abelino Valdéz, Seberino Valdéz, Antonio Aguilar, James W Dalling, Eben N Broadbent, Angelica M Almeyda Zambrano, Stephen P Hubbell, Maria Garcia-Leon. 2021. Local canopy disturbance as an explanation for long-term increases in liana abundance. Ecology Letters. DOI: 10.1111/ele.13881

Wright, S. Joseph, Calderon, Osvaldo, Hernandez, Andres, Paton, Steven, 2004. Are lianas increasing in importance in tropical forests? A 17-year record from Panama. https://doi.org/10.1890/02-0757