International Research Fellowship Program: Diversification of Amazonian Tree Lineages

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0402061FineThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Paul Fine to work with Dr. Asuncion Cano at the Universidad Nacional Mayor de San Marcos in Lima, Peru. This project will receive support from a University of Michigan Society of Fellows fellowship in addition to this award.The project is entitled "The diversification of Amazonian tree lineages: the role of environmental variation versus geographic distance." The goal of the project is to examine evolutionary relationships between sister populations of habitat endemic trees to reveal the ultimate causes of speciation in the genus Protium (Burseraceae), a common group of Amazonian trees which includes numerous edaphic (soil) specialists. Most evolutionary biologists believe that allopatric speciation (species formation by means of spatial isolation) is the dominant mechanism of diversification. The alternative hypothesis, that species diverge by means of parapatric speciation (species formation due to local adaptation to environmental variation in the absence of spatial isolation) is theoretically sound, has been supported by recent empirical studies, but remains untested in Amazonian trees.This is the first direct evaluation of parapatric speciation in Amazonian forests. First, the relative importance of edaphic heterogeneity and geographic distance are being evaluated in the structuring of populations of four common Amazonian tree species that have subspecific or varietal specialists on both white sand and clay soils. Next, the traits required for edaphic specialization are being measured, and the presence of gene flow between neighboring populations of white sand and clay populations quantified to see whether these species exhibit morphological divergence in the two soil types, even in the face of gene flow between populations. Unraveling the genealogy of each of these closely related taxa offers the opportunity to study the integration of micro and macro-evolutionary processes - how populations within a species become subdivided due to environmental variation and geographic distance, and the ultimate causes of speciation in this group. Director Cano is providing valuable experience in the National Herbarium, which houses many important collections from the Neotropics. One of this project's broader impacts is to pilot an extension of new databasing technology at the National Herbarium in Peru. This project represents a unique opportunity to build the foundation for future specimen-based research integrating phylogeny, biogeography, and ecological studies of tropical plants in Peru for students and faculty all over the world. In sum, this project contributes to a greater understanding of the processes that lead to diversification in Amazonian trees and is stimulating collaborations between scientists and students in Peru, Brazil, and the United States.