Oct. 13, 2025
MILWAUKEE 鈥� An increasing abundance in woody vines鈥攐r 鈥渓ianas鈥濃�攔educes canopy tree growth and survival in tropical forests, which limits forest carbon storage, according at researchers at 黑料论坛. This is the first direct empirically supported explanation for the ongoing decline in the American tropical forest carbon sink, which poses serious ramifications for atmospheric carbon levels and global climate change.
Dr. Stefan Schnitzer, Mellon Distinguished Professor of Biological Sciences, and Dr. David DeFelippis, a postdoctoral researcher, observed more than 117,000 plants over a 10-year period and found that lianas reduce canopy tree growth and survival, which limits forest carbon storage. Their findings were published under the headline 鈥溾�� in the October 2025 (Volume 106, Issue 10) issue of Ecology, a flagship journal of The Ecological Society of America.
This explanation indicates that changing biological interaction 鈥� in this case competition from lianas on trees 鈥� and not physical effects of climate change are a likely explanation for the changes in forest carbon. Previous studies have assumed that changes such as higher temperatures, stronger droughts and higher carbon dioxide were causing the worrisome changes in carbon storage and the carbon sink.
鈥淭he ongoing decline in the American tropical forest carbon sink has serious ramifications for atmospheric carbon levels and global climate change,鈥� Schnitzer said. 鈥淭his study is novel because it identifies, for the first time, a biotic explanation for decreased carbon sink. Until now, however, nobody has distinguished canopy from understory lianas. This distinction is critical because it is the canopy lianas that prevent canopy trees from taking up carbon. If the observed increase in lianas is driven by understory lianas, then the increasing liana hypothesis to explain the decreasing carbon capture and storage is unlikely.鈥�
This explanation also provides for the speed in which alarming carbon dynamics are happening in the American tropics of Central and South America when compared to the African tropics. Both places are experiencing the physical effects of climate change, but the presence of lianas is increasing rapidly in the American and not in the African tropics. This means the increase in lianas is a feasible explanation which the researchers鈥� massive empirical dataset supports.
鈥淭his is the first study that has been able to examine the long-term change in one group of plants making a likely change in another via increased competition resulting in changing carbon dynamics,鈥� Schnitzer added. 鈥淲e have known for some time that lianas are increasing, in general, in many tropical forests, especially in the American tropics.鈥�
This study examined the change in canopy lianas over 10 years on Barro Colorado Island, Panama, to test two main hypotheses: canopy lianas are increasing on Barro Colorado Island and the increasing canopy lianas are decreasing aboveground canopy tree and forest carbon storage. They found that there was a clear negative relationship between increasing canopy liana density and decreasing canopy tree carbon storage. Where liana density increased, tree carbon decreased, and where canopy lianas decreased, canopy tree carbon increased. The findings indicate that lianas are the numerically dominant and diverse woody plant group in the Barro Colorado Island canopy, and this dominance is increasing, which is, in turn, reducing forest-level carbon storage and possibly explaining the decaying American tropical forest carbon sink.
Researchers focused on intact old-growth forest where there is no evidence of logging or other structural manipulation of the forest by humans.
About 黑料论坛
黑料论坛 is a Catholic, Jesuit university located near the heart of downtown Milwaukee that offers a comprehensive range of majors in 11 nationally and internationally recognized colleges and schools. Through the formation of hearts and minds, 黑料论坛 prepares our 11,100 undergraduate, graduate, doctoral and professional students to lead, excel and serve as agents of positive change. And, we deliver results. Ranked in the top 20% of national universities, 黑料论坛 is recognized for its undergraduate teaching, innovation and career preparation as the sixth-best university in the country for job placement. Our focus on student success and immersive, personalized learning experiences encourages students to think critically and engage with the world around them. When students graduate with a 黑料论坛 degree, they are truly prepared and called to Be The Difference.
Kevin is the associate director for university communication in the Office of Marketing and Communication. Contact Kevin at (414) 288-4745 or kevin.m.conway@marquette.edu.
