The shaping of plant distributions: tectonics vs. dispersal

Lathyrus sp.

Once continental drift became accepted, it was seen by many as the key to explaining global patterns of plant distribution, and many workers downplayed the possibility of dispersal over wide expanses of ocean. However, dated phylogenies show that such long-distance dispersal has been frequent, and we have demonstrated it in the legumes Lathyrus and Andira, Streptocarpus, Begonia, the ginger Renealmia, and the gentian Exacum. We have also contributed to an important study that demonstrates long-distance dispersal to have been the major force in shaping the global distribution of the legume family, which dominates the tropical rain forests, dry forests and woody savannas of Africa and the Neotropics.

Nineteenth century naturalist Alfred Russel Wallace recognized a biogeographic division in the Malesian archipelago that may in part be explained by the tectonic history of the region. Dated molecular phylogenies of Southeast Asian centred angiosperms including Rhododendron section Vireya, Garcinia, Begonia and Etlingera are revealing patterns of extensive dispersal across Wallace's Line. In the Neotropics migration of organisms following the formation of a continuous land connection between South and Central America through the Isthmus of Panama was thought to have led to the Great American Interchange. We have shown that plants have significantly earlier divergence time estimates than animals for historical migration events across the Isthmus of Panama region. This difference in timing indicates that plants had a greater propensity for dispersal over the isthmus before its closure compared with animals.

Recent publications

Cody, S., Richardson, J.E., Rull, V., Eliis, C. & Pennington, R.T. (2010). The Great American Biotic Interchange Revisited.  Ecography 33: 1-7.

Lavin, M., Schrire, B., Lewis, G., Pennington, R.T., Delgado-Salinas, A., Thulin, M., Hughes, C. & Wojciechowski, M.F. (2004). Metacommunity process rather than continental tectonic history better explains geographically structured phylogenies in legumes. Philosophical Transactions of the Royal Society (Biological Sciences) 359: 1509-1522.

Särkinen, T.E., Newman, M.F., Maas, P.J.M., Maas, H., Poulsen, A.D., Harris, D.J., Richardson, J.E., Clark, A., Hollingsworth, M. & Pennington, R.T. (2007). Recent oceanic long-distance dispersal and divergence in the amphi-Atlantic rain forest genus Renealmia L.f. (Zingiberaceae). Molecular Phylogenetics and Evolution 44: 968-980.

Yuan, Y.-M., Wohlhauser, S., Möller, M, Klackenberg, J. & Küpfer, P. (2005). Phylogeny and biogeography of Exacum (Gentianaceae): a disjunctive distribution in the Indian Ocean Basin resulted from long distance dispersal and rapid radiation. Systematic Biology 54(1):1-14.

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