Biogeographic memory

[P.Hovenkamp]

At 09:00 AM 8/24/01 -0400, John R. Grehan wrote:
>For those interested I have responded so the points most recently raised by
>Hovenkamp with some additional comments on the different findings of
>panbiogeography and cladistic methods for the South East Asia region.
(...)


>>Do you mean it was accepted after the reference was omitted - or were
>>there more points that needed revision?
>
>I know of a case with a prominent journal where the editor declared that
>there would be no papers published in his journal that cited Croizat and
>turned down publication of a paper on that basis. Soon after the editor
>passed away, and the next editor allowed the paper to be published. This
>kind of censorship is very real and has had a very real influence on the
>dissemination of panbiogeography.
Granted. But still not something that Turner et al can be accused of...

>>All of Croizat's discussions are totally without reference to the value of
>>resolved schemes of relationships.
>
>I believe this is questionable, but it may depend on whether Croizat's
>comments on these issues met the criteria in mind.
>Croizat (1968) for example, notes the outstanding value of Corner's
>checklist on Ficus in that it provided such a detailed taxonomic
>arrangement that is was possible to associate progressively narrower
>affinities etc. Throughout Croizat's works there is a consistent use of the
>major systematic/taxonomic monographs of the time, thus emphasizing the
>need for the best available phylogenetic information. Perhaps at would make
>an interesting historical document to specifically address how Croizat
>used, commented on, and applied systematic studies and what the long-term
>implications have been.
I may have been hasty, basing my comments only on Croizat 1962 (Space,
Time, Form: The Biological Synthesis), and possibly (excusably?) even
overlooking some statements in those 822 pages.
The point remains that Craw, Grehan and Heads are quite adamant that
biogeographic analysis is not to be informed by phylogenetic analysis based
on other characters.

>>Likewise, in your book you are stressing that biogeographic analysis is
>>prior to the establishment of a natural classification.
>
>A natural classification being a combination of form and spatial
>relationships.
>
>
>>I quote again (p. 6): "their distributions are not distinguishable
>>according to their different means of dispersal".
>>A simple test: put the two maps before a reasonably well-informed audience
>>- ask them to indicate which of the two is more likely to be a group of
>>butterfly, which of freshwater fish.
>
>And I would repeat that they are not distinguishable by means of dispersal.
>There is no objective criterion for deciding which is which based on means
>of dispersal.

This raises the question how different two distribution patterns must be to
be distinguishable by such different means of dispersal. Given the choice
between a butterfly and a freshwater group, would one be safe in venturing
that a pattern ranging from New Guinea to Samoa is more likely to be the
butterfly and a pattern restricted to Borneo more likely the fish? I do not
ask for certainty - simply for a rational reason to make a choice.


>I believe the points raised by Hovenkamp show that Croizat's works are in
>deed relevant to all aspects of biogeography
That was certainly not my intention...

>and while we may disagree on
>the use of "censorship" to describe citation or the lack of it, the absence
>of citation in this case is telling. For example, a colleague of mine noted
>how the opening sentence of the abstract says the biogeography of Southeast
>Asia and the West Pacific is "complicated" by the bordering of two
>paleocontinents. In contrast Croziat's analyses suggests the biogeography
>is not complicated in this respect.

Then it must be other respects that make Croizat's analyses appear so
complicated ;-)

>Then the final sentence is even more
>telling: "We have not been able to trace common patterns." This is where
>historical citation or lack of may become critically important. If Turner
>et al are not able to trace common patterns by their methodology where does
>this leave Southeast Asia Biogeography? Is this the status quo? Is this an
>advance? The absence of citation of Croizat's work may lead to a very
>different impression than what might otherwise be made if his works were
>cited and discussed as Croizat's methodology did lead to the discovery of
>common patterns. That being the case one might discuss the relative merits
>of a method that does trace common patterns in the region and a later
>method that does not.

Quite a lot of systematic analyses pertaining to the region have been
performed since Croizat (1968). It might be a good idea if someone would
integrate these in a panbiogeographical framework. Preferably in less than
400 pages...

P. Hovenkamp
Nationaal Herbarium Nederland - Leiden
PO Box 9514
2300 RA  Leiden
The Netherlands
hovenkamp at nhn.leidenuniv.nl
http://nhncml.leidenuniv.nl/rhb