Researchers are using statistical and phylogenetic methods to help understand the biogeography of palms.
25 Sep 2012
Washingtonia filifera, a member of the fan-leaved palm tribe Trachycarpeae, occurs in North America where the group is believed to have originated (Image: Bill Baker).
Two scientific papers co-authored by Kew researchers on palm biogeography have been published recently.
Determinants of palm distribution
The first paper, published in Global Ecology and Biogeography, resulted from collaboration with Aarhus University. The research exploited Kew’s World Checklist of Palms and the geographical distribution information that it contains to explore the current and historical determinants of palm distribution and diversity patterns.
Using macroecological statistical methods, the authors found that palm species richness patterns are significantly affected by historical factors, whereas the distributional limits of the family are primarily determined by current climate. Quaternary climate change was shown to have a significant influence on diversity patterns, along with other pre-Quaternary factors, which may have included extinction in Africa or the long-term climatic stability of the Asian and American tropics.
Origins of fan-leaved palms
The second paper, published in Systematic Biology with collaborators from Colorado State University, centred on the fan-leaved palm tribe Trachycarpeae. Using six DNA regions, the authors built a large phylogeny of the tribe, resolving relationships that were poorly understood previously.
Using molecular dating methods and maximum likelihood ancestral area reconstruction methods, they inferred that the group originated in the North/Central Americas, undergoing its earliest diversification of extant lineages around 38 million years ago. Geological events such as Bering and the North Atlantic land bridge formation and the evolution of the Caribbean and South-East Asian archipelagos were interpreted as important in the evolutionary history of the tribe, which has undergone a series of separate radiations that link to Miocene dispersal events.
Item from Dr Bill Baker (Head of Palm Research, RBG Kew)
Kew Scientist, issue 41
Bacon, C.D., Baker, W.J. & Simmons, M.P. (2012) Miocene Dispersal Drives Island Radiations in the Palm Tribe Trachycarpeae (Arecaceae). Systematic Biology 61: 426-442.
Kissling, W.D., Baker, W.J., Balslev, H., Barfod, A., Borchsenius, F., Dransfield, J., Govaerts, R. & Svenning, J.C. (2012) Quaternary and pre-Quaternary historical legacies in the global distribution of a major tropical plant lineage. Global Ecology and Biogeography 21: 909-921.
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