Plant-Insect Diversity, Paleobiology, and Paleobiogeography From Early Eocene Neotropical Forests

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The early Eocene hyperthermals were intervals of rapid and extreme warming that occurred ~56-52 million years ago. The hyperthermals recorded the highest global temperatures in the last 66 million years, and their fossil record provides a snapshot of life in a greenhouse world. Most studies of life during these warming intervals have focused on geographical regions between the tropics and poles. Very little is known about ancient tropical forests during the early Eocene. In this project, the early Eocene plant fossil record of northern Colombia are being intensively sampled. These collections will provide a unique and previously undescribed record of Central and South American plants from which their evolution and function can be evaluated in relation to past environmental change. With such records, our understanding of the limits and long-term responses of tropical rainforests to warming will advance. This project will foster the scientific training of undergraduate students in state-of-the-art lab techniques. The investigators will continue to increase paleontological awareness in local and rural communities in Colombia through training of public school teachers. This project will use the paleobotanical and sedimentary record from northern Colombia to test for biotic responses of Neotropical forests to early Eocene warming events. The research area includes three previously undescribed plant fossil localities that span the Paleocene-Eocene boundary and complement previously described Late Paleocene floras in Colombia. Considering that the plant fossil record provides a natural experiment in which to observe the long-term response of tropical rainforests to temperature increases, this project is focussing on 4 questions: 1) Did the early Eocene hyperthermals lead to a diversification or a collapse of tropical biomes in northern South America? 2) Did plant evaporative cooling change during these rapid increases in temperature? 3) How did forest composition and plant-insect interactions change during the early Eocene? 4) Were the early Eocene forests in northern South America similar in biogeographic composition to extant forests in the same region? By involving undergraduates in examining these research questions, this project will advance discovery and understanding while promoting teaching, training, and learning.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.