Biogeographic memory

[P.Hovenkamp]

Dear John and all,

I found John Grehan's this posting only when I returned from my holiday -
hence the somewhat late reply.
I find many of your remarks challenging, and some completely off the mark,
to the point of being unnecessarily insulting.
I resent the suggestion that we "censor" Croizat. It suggests that you have
no notion what censorship really implies. Croizat's books weigh down
bookshelves all over the world - and nobody ever got fired for citing him.
I even wonder whether any paper ever was rejected merely for citing
Croizat. That would begin to come closer to real censorship, but is not
something we can be accused of.
That most people (including us) refuse to cite him in every paper dealing
with biogeography is something completely different. On our part, it may
simply be explained by our aim to develop the field of cladistic
biogeography - integrating phylogenetic information into biogeography.
Croizat's view - and yours (going by your book with Craw and Heads) is that
biogeography informs phylogenetic reconstruction. This alone makes the
whole Panbiogeographic attempt irrelevant to our aim, which was to do
biogeography informed by phylogeny.

Some other comments:
At 09:20 AM 8/9/01 -0400, you wrote to Taxacom:
>I was intrigued to read the following recent paper in Journal of Biogeography:
>
>Turner, H., Hovenkamp, P. and P. C. van Welzen. 2001. Biogeography of
>Southeast Asia and the West Pacific. Journal of Biogeography 28: 217-230.
>
>In their abstract the authors declare the biogeography of this region to be
>the result of dispersal from two centers of origin based upon geological
>theory, the centers being Laurasian and Gondwanan. Having asserted

"declare", "asserted" - these are strong words to paraphrase our abstract
in which we state that two patterns "can be expected"

>this to
>be the truth of southeast Asian biogeography they decide to reconstruct the
>biotic history using two large data sets analyzed using cladistic methods.
>The result  - weakly supported general patterns that do not allow general
>conclusions!
>
>So, according to Turner et al, the state of modern biogeography for this
>region is such that we cannot even reach general conclusions (echoes of
>Nelson and Platnick's 1981 "unanswered questions"?). Perhaps their findings
>are not really that surprising since their approach is based on Darwinian
>centers of origin and dispersal using the same kind of geological
>preformationism.
Careful reading of the paper will reveal that in a first analysis we tried
to allow for the existence of two of these origin/dispersal scenario's but
in the end lumped all data together and simply analyzed the whole dataset
together. Our conclusions are primarily based on this last analysis. The
methodology we used (Brooks Parsimony Analysis) is otherwise not
particularly based on origin/dispersal concepts.

>But what is most interesting (or informative  depending on
>one's perspective) is the way the place their findings in the historical
>context of biogeographic history  or should I say do not place their
>findings in historical context. The question of southeast Asian
>biogeography is one which calls for consideration of the major approaches,
>and in this paper there is a resounding silence about the obvious  that
>being the extensive and detailed studies by Croizat (e.g. 1958, 1968). Now
>this might just be considered sour grapes on my part, but I hope that it
>can be seen to be a troubling aspect of the science. If deliberate
>censorship of unwelcome opponents is to be condoned it raises the question
>of whether proper academic standards are applicable to biogeography, and in
>which case can biogeography be received with respect by the greater
>scientific community?

On censorship, see my opening remarks.
On Croizat and Panbiogeography, it is interesting to consider why people
generally ignore Croizat's work.
For my part, I may still be haunted by the ghost of Van Steenis who was
rather dismissive of Croizat after having found that Croizat sometimes
simply had his facts wrong. More importantly, my eyes always glaze over
after having had to read one page by Croizat, never with less than two
disparaging remarks towards unspecified or specified persons. Or towards
the theory of evolution.
Then, eager to learn something about panbiogeography from a more concise
book, I open Craw, Grehan and Heads only to be baffled already by their
statement with regard to the very first distribution maps they show (fig
1-1): "the distributions of these groups are geographically similar" and
"are not distinguishable according to their different means of dispersal"
In fact, one group (freshwater fish) is restricted to areas that have (or
have had in the  recent past) a land connection, the other (butterflies!)
extends to far-out oceanic islands that certainly never were connected to
the mainland area! How is it possible to ignore such differences?
There is a lot to this book that merits discussion. For one thing, I
totally agree with your aim to bring back a sense of locality to
biogeographic analysis, abhorring (as I think you do) biogeographic
analyses where no maps are considered.
But this will have to do for now.



>Censorship of this kind results in a misrepresentation of the state of a
>science. For example, in contrast to their weakly supported findings that
>the constraints of earth history are said to be low and the common patterns
>of biotic history cannot be traced with any confidence we may contrast with
>Croizat's (1968) insights that include the following:
>
>"Analyzed in regard of different nodes of its distribution, whether in the
>Bay of Bengal, the Gulf of Siam, on the approaches of Southern
>Formosa/Luzon, Micronesia, by the islands with the triangle
>Sumatra-Borneo-Java, Ficus yields ready evidence for palaeogeographic and
>tectonic factors tending to make not only possible but fruitful, for
>geologists and bigoeographers alike, a much closer collaboration than
>heretofore possible. It is strongly indicated that 'modern' dispersal had
>its inception around Mid-Jurassic times."

Which I find a singularly unspecific conclusion....

>So one has a choice between unresolved speculation of Turner et al, or the
>documented correlations between tectonics and distribution by Croizat.
>Whatever the 'truth' of Southeast Asia, or anywhere else for that matter, I
>think the state of knowledge will not be served well by the absence of
>historical memory.

Nor by crying "censorship!" when it is simply a matter of not referring to
Croizat.

>Croizat, L. (1968a). The biogeography of the tropical lands and islands of
>Suez-Madagascar: with particular reference to the dispersal and form-making
>of Ficus L., and different other vegetal and animal groups. Atti Istituto
>Botanico Universita Laboratorio Crittogamico. Pavia, Serie 6. 4, 1-400
>
>John Grehan
>Frost Entomological Museum
>Pennsylvania State University
>Department of Entomology
>501 ASI Building
>University Park, PA 16802. USA.
>
>Phone: (814) 863-2865
>Fax: (814) 865-3048
>
>Frost Museum
>http://www.ento.psu.edu/home/Frost/index.html

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