[Taxacom] Fwd: Woodpeckers, primates, as well as the Wallace Line gauntlet

[John Grehan]

For once I am in agreement with Ken. I think Ken's comments on the means of dispersal for albatrosses, salmon, monarch butterflies etc are right on and make the point very effectively that assuming dispersal as a universal quality for a species (i.e. that is not a contingent ecological quality) as a biographic method does not work in the real world of biogeography. The fact is that such approaches have not been productive in biogeography. 

Bird nesting in particular is biogeographically very informative and often illustrates tectonic uplift as the nesting sites may stay in place even though they may eventually become montane. It's the same processes that put formerly mangrove plants into the tops of mountains. And it was this same process that possibly brought marine life onto land.

Darwin once predicted that when we finally know with confidence the means of disposal of species we will know with confidence the former extent of land. Well he was wrong. 

John Grehan

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
Sent: Sunday, May 29, 2011 9:11 PM
To: taxacom at mailman.nhm.ku.edu
Subject: [Taxacom] Fwd: Woodpeckers, primates,as well as the Wallace Line gauntlet

Hi Michael,
      Although I was mentioned further along in your post, I will only respond to the first paragraph (that is all the time I have tonight).
First, I don't understand why you make an exception for colonial organisms.  Although they cannot disperse very far vegetatively, they
can often disperse large distances through sexual reproduction.        
     As for albatrosses, I agree that they may have extremely large feeding ranges, but reproductive needs (nesting sites, etc.) are very limiting.  It is sort of like salmon compelled to return to their birthplace to spawn.  Whether it is quite as chemically-based as salmon, albatrosses generally return to a home-base to breed.  This reproductive bottle-neck limits dispersal at that crucial part of their life cycle.  
      Monarch butterflies are somewhat limited for a different reason.
Their reproductive range is actually relatively widespread in eastern North America, but it is their particular needs for a limited wintering
ground that keeps them from dispersing further.           
        It only takes one restriction in one particular part of the life cycle to keep dispersal in check.  Think of it as an "evolutionary" weak link.  Albatrosses may be able to range far and wide when not reproducing, but that critical time of reproduction for a species limits them to a very limited breeding range.  Whether this is due to predation of chicks, availability of nesting sites, food sources to feed the chicks, or other factors (or all of the above), it puts limits on the dispersal of the species.  So that is my answer to your questions: "Why?
How?
              ----------Ken       
            
--------------------------------------------------------
Michael Heads wrote:
       Every individual of every plant and animal (except in colonial
organisms) has dispersed to where it is now. The problem lies in integrating that process - normal physical movement - with other processes in phylogeny and geography, especially range expansion and vicariance. The physical movement of individuals may have little or nothing to do with the distribution pattern of their clade. Jim pointed out the paradox in ferns and marine groups with pelagic larvae, and many other authors have discussed the problem. Individual albatrosses fly around the world at the drop of a hat, and yet the clades have very precise, allopatric, locally endemic, breeding ranges. Why? How? 
  


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