[Taxacom] Biogeography of Australasia

[Fred Schueler]

Quoting Michael Heads <m.j.heads at gmail.com>:

> Surprisingly, even species with long-lived, planktonic larval stages also
> show very high levels of geographic structuring.
>
> On Tue, Mar 25, 2014 at 7:26 PM, Stephen Thorpe
> <stephen_thorpe at yahoo.co.nz>wrote:
>
>> Yes, marine species with direct development (no larval stage) can show
>> local endemism (the sea to them is like the air to us!)


* maybe we need a causally-based theory of local  
[co-?]adaptation/vicariance. Is there a literature of studies of the  
population biology of introductions in terms of understanding the  
biogeographic dispersalist/vicariance dispute?

I'm inspired to suggest this by the failure of many alien species  
which, despite successful somatic growth, fail to reproduce in an  
alien landscape, most conspicuously widely planted trees (thank you,  
Picea abies). It's part of the standard understanding of invasion  
science that after a tenuous start of several to many generations, an  
introduced species may undergo a bit of selection for some local  
adaptation, and then become invasive.

It seems to me that the preference for vicariance over dispersal as  
explanation for biogeographic patterns assumes that there's a general  
failure of dispersal events by waif individuals. Of course this would  
be hard to study, since the efforts of invasion biologists have  
demonstrated that it's very hard to even implement policy-mandated  
rapid-detection-rapid-response to extirpate new colonies of species  
known to be invasive, let alone study the population biology of new  
populations.

Maybe a part of such a theory would be comparisons of taxa with  
different life histories such as the larval/direct development of  
marine species: the establishment of remote colonies of a taxon is an  
unobservable event, sort of like the Higgs boson, so we need a  
comprehensive theory of all aspects of its causes and consequences.

written speculatively in nearly complete ignorance of any recent  
literature on this subject,

fred.
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