In today’s Academic Minute, Dr. Stephanie Pau of Florida State University explains why tropical forests may already have all the heat the ecosystem can tolerate.
Stephanie Pau is an assistant professor of biogeography at Florida State University where her research investigates the impact of climate change on plant species, communities, and ecosystems. Her work uses a combination of field surveys, remote sensing data, and statistical modeling to study how tropical forests and grasslands are responding to global climate change. She holds a Ph.D. from the University of California Los Angeles.
Dr. Stephanie Pau - Tropical Forests and Climate Change
I study how the growth of tropical forests is impacted by climate change. Tropical forests are incredibly diverse and dynamic, showing rapid and longer-term changes in growth and mortality. At a large spatial scale, the primary limiting factors on plant growth are temperature, rainfall, and light. Tropical forests are generally warm and wet year-round, so their growth and productivity may be most limited by light and cloud cover. On the other hand, tropical forests may be highly sensitive to temperature because they are living closer to their upper temperature tolerance.
Recently I’ve worked with an international team of scientists and we investigated the effects of temperature, rainfall, and cloud cover on flower production at two contrasting sites—a seasonally dry and a wet tropical forest. At both these sites long-term ground observations of flower productivity have been collected and we combined these data with satellite observations of cloud cover over the past several decades because clouds are one of the largest uncertainties in climate change science.
What we found was that whereas clouds have had a variable effect at each site, and primarily on a seasonal timescale, temperature has been the most consistent effect on flower productivity at both sites and across several timescales. There has been a steady long-term increase in flower productivity at the seasonally dry site, where flower production has increased at about 3% each year on average. This long-term increase appears to be tied to temperature and not clouds. Even though temperature increases are projected to be smaller in the tropics than in high latitude regions such as tundra or arctic ecosystems, our work shows that tropical species are sensitive to only small degrees of warming.