Colonization of microclimates

Gene Spears spears at bobcat.lmc.edu
Thu Jun 11 09:32:27 EST 1992


In article <1992Jun10.224704.13682 at dsd.es.com> rthomson at mesa.dsd.es.com (Rich Thomson) writes:

>>While each little habitat "island" may have a limited number of 
>>species (and classic island biogeographic theory suggests that the number of 
>>species in each "island" is at equilibrium, and your efforts would only 
>>temporarily increase diversity), the different "islands" may have different 
>>assemblages of species.

>Where can I study about this "classic island biogeographic theory"?
>If we're talking the kind of island in the ocean, how is that relevant
>to a place like the middle of a continent?

	The best source for the classic theory is a short book by 
MacArthur & Wilson called (appropriately enough) "The Theory of Island 
Biogeography".  The reading is a bit heavy in spots, but the overall ideas 
are reasonably straightforward.  Basically, the idea is that the number of 
species found on an island depends on the rate of immigration and 
extinction, creating a dynamic equilibrium.  Even though the particular 
species found on an island will change over time, the number of species 
should remain relatively constant.  Variables like island area and distance 
from the mainland also effect the equilibrium number by affecting 
immigration and extinction rates.  More recent research shows that things 
are probably a bit more complicated than the equilibrium model 
predicts.
	A lot of research has been done to suggest that isolated 
patches of habitat (like the fumaroles you described) can be considered as 
islands, even though they're surrounded by dry land.

>>      The system that you describe would be an ideal one for ecological 
>>studies of extinction and colonization.  Better to leave it alone for some 
>>future research.

>Better get there before the cows get at it, then.  This area also
>includes the following "goodies": plenty of monocrop farming right
>next door, the free world's largest Beryllium mine, various mining
>prospects, garbage dumps, and a cinders mine (for garden lava rock).
>This may give you a different idea of what this place looks like (my
>first description only described the aspects relevant to my query);
>this is definately *not* a pristine, untouched environment.

Jeeze, apparently not.  I liked the first description of the site much 
better.  Well, scratch that summer vacation to Utah.....

>My basic point is: man's current effect on this area doesn't seem
>positive, so how can an individual act in such a way as to counteract
>the negative effects of man's other endeavors?  I'm thinking something
>similar to the man who planted acorns in Southern France after WW II,
>reforesting an entire locale by himself by patient, persistent
>planting of acorns.

Something that is frequently done here in the southern Appalachians are 
"rescue" attempts when a highway is being constructed or expanded.  People 
go through the surveyed areas and dig up flame azaleas, trilliums, orchids 
and other plants in the road right-of-way.  Most of these wind-up in people'
s backyards, but some are transplanted back in adjacent woodlands.
	Much of the vegetative restoration work at local strip-mines has had 
little success because seedlings perished in the harsh, unvegetated soil 
in which they were planted.  They concluded that a good mulch layer was the 
simplest, least expensive way to increase successful reclamation.

>Would Johnny Appleseed need an environmental impact statement today?

>                                               -- Rich
>-- 
>       Repeal the personal income tax; vote Libertarian in 1992.
>Disclaimer: I speak for myself, except as noted; Copyright 1992 Rich Thomson
>UUCP: ...!uunet!dsd.es.com!rthomson                    Rich Thomson
>Internet: rthomson at dsd.es.com  IRC: _Rich_             PEXt Programmer

G. Spears
spears at andy.lmc.edu



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