[Taxacom] Nothofagus (Chile-New Zealand distributions)

Geoffrey Read gread at actrix.gen.nz
Tue Jul 27 02:43:02 CDT 2010


Hi Ken,

As a marine biologist I'm talking only of today's marine dispersal routes.
You think Chilean logs taking the Thor Heyerdahl route off from up Peru
way would reach the South West of Tasmania?  I think that is highly
improbable. Whereas there is a massive current moving South American
floating material along the southern route ever eastwards across the
Atlantic, then Indian Ocean, then Tasmania and NZ. It is apparently moving
objects along steadily at 35 km per day and more.

South American Nothofagus species of natural driftwood predominated on
Heard Island, mid Indian Ocean (about 73 deg E, 53 deg S) according to
Smith, J. M. B.; Rudall, P. ; Keage, P. L. 1989:  Driftwood on Heard
Island.  Polar Record 25(154): 223-228. So that's come across the Atlantic
and half way across the Indian Ocean.  Not far to Australasia from there. 
The paper also mentions drift bottles released in the Drake Passage  were
recovered in Tasmania, and New Zealand.

But obviously the chances of terrestrial life or coastal marine life
surviving that length of voyage clockwise round the South Pole, either NZ
=> Chile, or the longer Chile => NZ, are very very small. Benthic marine
sessile inverts may not have an advantage as the floating algae which
carry them off will sink long before timber does.

Geoff

>>> On 27/07/2010 at 1:35 p.m., Kenneth Kinman wrote:
>       You are correct.  I shouldn't have used the word "directly", which
> implies a straight line.  The Nothofagus driftwood which went from Chile
> to Tasmania no doubt was swept north of 30 degrees and then west along
> the return current.






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