Raven and Axelrod "biogeography"

[John Grehan]

In an earlier posting a list member asked about how I would
comment on the biogeographic classification used by Raven
and Axelrod (1974). As I received that email at home and
cannot recall that person's name.

However, I took at look at their paper and believe the best
way to address their approach is for that person to give
a specific example of their substantiation of a biogeographic
region that I can then repsond to.

Their paper is interesting historically for the absense of
any biogeographic maps (but the historical geology is
mapped!). This absence reflects, in my opinion, a historical
and current prejudice against geography by many biologists.

Much of the paper is speculative and assertive rather than
analytical. I will comment here on their description of
Fagaceae. They say that it is primarily "Laurasian". By that
I presume they mean that most of the taxa occur on areas that
are included within the boundaries of a geographic area
defined in geology as Laurasia. Whether this is sufficient
to constitute a "biogeographic" area is something I doubt
and they have not substantiated to my knowledge.

They also assert that Nothofagus reached the southern
Hemisphere from the North. There is no biogeographic
analysis presented in support of this assertion.

They "explain" the absence of Fagaceae from the high mountains
of north-central Africa as the expansion of dry climate. They
do not consider the possiblity that the Fagaceae were never there
in the first place.

John Grehan