Increased forest productivity leads to a demographic advantage for lianas over trees

What is it about?

Lianas are a group of climbing woody vines that include many well-known members such as poison ivy, wild grape, and Virginia creeper. In tropical climates, lianas are especially common and diverse and many species are increasing in abundance at a remarkable rate. Increasing lianas is a concerning trend since lianas negatively effect the carbon uptake and storage capacity of forests and disrupt forest succession and function. However, the mechanisms driving liana proliferation remain unclear. Understanding the process of increasing lianas is hampered by the challenges of predicting ecosystem-level outcomes from individual plants' physiological responses, especially when reciprocal interactions between plants are at play. Our study presents a theoretical framework informed by comprehensive physiological and demographic observations collected in Panamanian tropical forests, which unites plant physiology, demography, and epidemiology. The resulting analysis suggests that climate change factors that promote forest productivity, such as the rising atmospheric concentration of CO2, provide a competitive advantage to lianas and contribute to the observed global increase.

Featured Image

Photo by Anastasia Vishnevetskaya on Unsplash

Photo by Anastasia Vishnevetskaya on Unsplash

Why is it important?

Our model reveals the environmental drivers that support liana proliferation, how liana proliferation may impact forest structure, and whether these changes are transient or permanent. The study also demonstrates that liana proliferation may still manifest at the ecosystem level even when lianas and trees show a similar physiological performance increase (i.e., growth) in their response to environmental change. This finding underscores the need for caution when extrapolating plant-level responses without a proper framework that couples physiology and demography, especially when studying interacting growth forms that differ in life-history and allocation strategies.