Climate change linked to more flowery forests: Study

Florida State University researchers have revealed a surprising relationship between surging atmospheric carbon dioxide and flower blooms in remote tropical forests.

Studying the rich tropical forests of Panama's Barro Colorado Island, the researchers found that climbing rates of carbon dioxide have set the stage for a multi-decade increase in overall flower production.

Lead author Geography Stephanie Pau said, "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."

The findings suggest that tropical forests, which have evolved over millennia to flourish in warm, equatorial conditions, might be more sensitive to subtle climatic changes than some ecologists predicted.

"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," Professor Pau added.

The team evaluated a record of plant material collected and archived by researchers on the island for over 28 years.

They then examined a host of climatic drivers -- temperature, rainfall, light and carbon dioxide - that affect the annual flowering activity and flowering duration of the different species present in the forest.

"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," Professor Pau stated.

Plants convert atmospheric carbon dioxide into energy in the form of sugars, which they can use to fuel any number of vital life processes. As more carbon dioxide is released into the atmosphere, plants have an opportunity to produce a bounty of new energy.

The dramatic, long-term rise in flowering indicates that the forests of Barro Colorado Island are allocating those swelling stores of energy toward increased reproductive activity.

"Tropical species may generally be more sensitive than we expected, but not all species are responding the same," Pau said.

"For some species, the 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," she added.

As atmospheric carbon dioxide concentrations keep climbing -- and as the global climate changes accordingly -- temperamental tropical forests may continue to experience new and surprising ecological shifts.

The findings are outlined in a paper published in the journal Global Change Biology.