[Taxacom] More Map of Life method
Kidd, David M
d.kidd at imperial.ac.uk
Fri Nov 19 05:10:33 CST 2010
Some thought on John's last message...
I do not advocate a specific methodology, so please don't get hung up on envelopes and averaging. You have a tree and some spatial information. Why not plot a quick envelope geophylogeny to inspect your data just like you use a box or scatter plot before getting into some serious hypothesis testing?
Geophylogenies are simply georeferenced trees that may represent extant biogeographic pattern or alternatively an explicit taxon history. In retrospect, perhaps 'spatial tree' whould been a more neutral term than geophylogeny.
Whichever methodology you prefer, if the result can be represented as a tree linked to spatial data then it can be represented as a geophylogeny. If historical biogeographical analysis are made available as digital representations then different models can be compared in a spatially explicit environment. The meaning attached to the branchs connecting nodes will vary with methodology and scientists interpretation. I personally believe that congruence between models can be used to make reasonable inferences of history , although these will always be contingent on further information. For example, if phylogeographic pattern, coalescent signitures of population expansion and ecological niche models all indicate expansion from a glacial refugia then I believe (for the moment). If the same patterns are found in other taxa, even better! As we go back in time evidence will become more fragmented. I still, however, believe that congruence between current taxon ranges, present environmental correlates and past environmental reconstructions, and fossil ranges provides evidence of past taxon history. Morrene's recent attempt to devise conceptual links between methodologies is, in my opinion, a real step forward towards a modern pleuralistic approach to historical biogeography. Such a multifaceted approach will require the direct comparsion of the results of different methods. Someone in the US should apply for a NESCent working group/catalysis meeting to futher develop these ideas.
I think exploring the connections between panbiogeography and geophylogenies is a worthwhile undertaking. I decided not to include the paragraph on panbiogeography in the paper as I, and others who read drafts, believe it requires a more detailed discussion than there was room to accomodate in this paper. This is probably not the place to start a debate on the merits of panbiogeography versus other historical biogeographic methods; however, it is clearly not liked by many (I suspect often as the result of received wisdom, rather than considered thought). Nevertheless, panbiogeography has a clear image problem, one reason for which is the rejection of phylogenetic in preference to taxonomic hypotheses, which also sidelines time. Other problems arise from a lack of statistical rigour in identifying congrence between tracks, confusing terminology and a general rejection taxon histories which interest many others. I do not raise these issues to stimulate a debate but instead mearly to state the contextual background to discussing panbiogeography.
David M. Kidd
Center for Population Biology
Silwood Park Campus
Imperial College London
0207 594 2470
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