[Taxacom] Nothofagus (Chile-New Zealand distributions)

Lyn.Craven at csiro.au Lyn.Craven at csiro.au
Mon Jul 26 23:31:24 CDT 2010


 

Austral biogeography is fascinating, all the more so because one or two swallows do not make a Spring.    The present distributions both of Don's Diptera and of Nothofagus may require explanation requiring a more or less entire Gondwana.    But the distributions of, for example, Fuchsia, Taraxacum and other daisies, and it would seem the ratites in the light of recent publications, are indicative of a post break-up dispersal.    

The distribution of soil symbionts adds spice.  What is known about the symbionts of Nothofagus?     Do they occur widely and outside the present range of Nothofagus (i.e. which came first, the mycorhiza or Nothofagus)?    Does Nothofagus only associate with a limited number of species/genera of symbiont, or is it more catholic in its requirements?

Regards,     Lyn



-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Don.Colless at csiro.au
Sent: Tuesday, 27 July 2010 1:02 PM
To: kennethkinman at webtv.net; taxacom at mailman.nhm.ku.edu
Cc: taxacom at mailman.nhm.ku.edu
Subject: [ExternalEmail] Re: [Taxacom] Nothofagus (Chile-New Zealand distributions)

There are many taxa (mainly genera) of the "Lower" (i.e. ancient) Diptera that occur in SE Australia, New Zealand (some), and Chile-Patagonia - and not in the northern hemisphere. Trans-ocean dispersal seems extremely improbable, when compared with Gondwanan vicariance. Lars Brundin even made a detailed cladistic analysis of a single subfamily of Chironomidae and demonstrated extremely convincing patterns.   
 
Donald H. Colless
CSIRO Div of Entomology
GPO Box 1700
Canberra 2601
don.colless at csiro.au
tuz li munz est miens envirun

________________________________________
From: taxacom-bounces at mailman.nhm.ku.edu [taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman [kennethkinman at webtv.net]
Sent: 27 July 2010 00:33
To: taxacom at mailman.nhm.ku.edu
Subject: [Taxacom] Nothofagus (Chile-New Zealand distributions)

 Dear All,
        Question:  If a large Nothofagus tree (with ripening fruit attached), or an island-like clump of a number of such trees, floated in fast-moving currents from Chile to New Zealand, would some of the ectomycorrhizae in their roots survive the journey?  If so, such dispersal of whole trees would preserve the symbiosis. The fruits release their seeds and the fungus (or its spores) is also there to continue the symbiosis in New Zealand.  Nothofagus driftwood is known to have floated from South America to Tasmania, so the shorter trip to New Zealand would presumably be an even less rare event.
             --------Ken

----------------------------------------------
buyck at mnhn.fr wrote:
Dear taxacom-botanists,
There is one element missing in the discussion of Nothofagus and it seems very essential to me : Nothofagus is an obligatory symbiotic tree with specific terrestrial, ectomycorrhizal fungi. Seed dispersal over long distances may have happened and even germination, but subsequent development of the plant is very unlikely without the specific fungal symbionts being present. You can not discuss the dispersal of a symbiosis and completely ignore the evolutionary history of (one or more
of) the implicated partner(s). One publication that briefly discusses this element is Pirozynski KA. 1983. Pacific Mycogeography: an appraisal. Australian. Journal of Botany Supplementary Series 10:
137-159
bart


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