120 Million Years of Tropical Forest Evolution

Carlos Jaramillo
Smithsonian Tropical Research Institute, Panama

jaramilloc@si.edu

The origin and development of Neotropical biomes are central to our understanding of extant ecosystems and our ability to predict their future.  During the Cretaceous, biomass of tropical rainforests was mostly dominated by gymnosperms and ferns, forest structure was poorly stratified and the canopy was open and dominated by gymnosperms.  Extant tropical rainforests first developed at the onset of the Cenozoic, as a result of the massive extinction of the Cretaceous-Paleocene boundary.  Paleocene rainforests were multistratified, with an angiosperm-dominated canopy that had high photosynthetic potential. Tropical climate has followed global patterns of warmings and coolings during the last 60 My. Rainforest diversity has increased during the warmings while it has decreased during coolings. Several extant biomes, including paramos, cloud forest, savannas, and dry/xerophytic forest, have developed significantly during the late Neogene at the expense of the reduction of the rainforest.  Timing and drivers of these changes are still unknown but they seem to be related to the onset of our modern, cool-state climate since the onset of the Pleistocene, 2.6 Ma ago.

Recent publications:

Jaramillo, C., 2018, Evolution of the Isthmus of Panama: biological, paleoceanographic, and paleoclimatological implications, in Hoorn, C., and Antonelli, A., eds., Mountains, Climate and Biodiversity: Oxford, John Wiley & Sons, p. 323-338.

Jaramillo, C., et al, 2017, Miocene Flooding Events of Western Amazonia: Science Advances, v. 3, p. e1601693.

Jaramillo, C. and Cardenas, A.  2013 Global Warming and Neotropical Rainforests: A historical perspective. Annual Reviews of Earth and Planetary Sciences 41: 741-766.