While most scientists are reporting the negative aftermaths of climate change – melting glaciers, increasing water levels, more frequent coral bleaching, etc. – a new study by Florida State University has observed a cunningly unexpected response of tropical forest to increasing atmospheric carbon dioxide levels and changing climate: higher flower production.
“It’s really remarkable. Over the past several decades, we’ve seen temperatures warming and carbon dioxide increasing, and our study found that this tropical forest has responded to that increase by producing more flowers,” explains Stephanie Pau, lead author and an assistant professor in geography.
Carbon Dioxide Is the Main Driver
The study, which was published in the journal Global Change Biology, focused on the tropical forests of Panama’s Barro Colorado Island. The researchers have collected and archived plant material on the island for 28 years. From this record, it was analyzed how would four climatic drivers – namely, temperature, rainfall, light, and carbon dioxide – affect the annual flowering activities and duration of various species that can be found within the island.
“What we were able to do in this paper is ask why flower activity has been increasing over the long term. We found that atmospheric carbon dioxide clearly seems to have had the largest effect on the increase in flowers,” Pau explains.
Atmospheric carbon dioxide is converted by plants into energy in the form of sugar. This energy is what fuels their vital biological processes. Therefore, when there is more carbon dioxide present in the atmosphere, plants can produce more energy. Ultimately, as evidenced by Barro Colorado forests, this abundance of stored energy results in increased reproductive activity.
Tropical Species Are More Sensitive to Climate Change than Expected
The study’s findings suggest that tropical forests can be more sensitive to even a slight change in climate than what was projected by some ecologists. Pau said, “Tropical forests have evolved in generally stable climates. So while they may not be warming as much as some higher-latitude ecosystems, these tropical species appear to be much more sensitive than we might have expected.”
“These tropical species have evolved in warm regions, so there may be an expectation that climate change won’t affect them. But what we’ve shown is that they are in fact extremely sensitive to even small changes in their climate,” Pau adds.
Not all species exhibited continuously increasing flowering activities with increasing carbon dioxide levels, though. Other species, such as certain canopy trees and lianas, have recently exhibited more stabilized flowering activities.
“Tropical species may generally be more sensitive than we expected, but not all species are responding the same. For some species, responses to increasing carbon dioxide seem to have reached a ceiling. These are the kinds of trends that we can only identify with long-term records like the one used in our research.”