permaculture

[Rain Tenaqiya <raincascadia@yahoo.com>]

While I sympathize with much of what Toby is saying, I feel like I need to 
remind everyone that disturbance is an essential part of wild ecosystems.  
Humuns are not the only source of disturbances, and most ecosystems have some 
cataclysmic disturbance at least every few hundred years.  When an invasive 
exotic species is introduced into a relatively undisturbed ecosystem, it may 
not displace many individuals of native species at first.  But once there is 
a disturbance, whatever its source, the invasive exotic may outcompete or 
overeat the natives in the new succession.  Ecosystems are chaotic systems 
which are sensitive to initial conditions.  When an exotic species is 
introduced, the initial conditions change which means the 'climax' ecosystem 
may be radically different from the one before.  Examples I've witnessed:
 
1.  Undisturbed California coastal scrub next to a line of blue gum 
eucalyptus trees slumps, opening the soil to colonization by eucalpytus 
seeds, ultimately resulting in a forest ecosystem.
 
2.  Relatively pure native California bunchgrass meadow disturbed by vehicle 
tracks and swale building recolonized by exotic annuals.
 
Everything gardens and invasive exotic species are no exception.  Introducing 
them even to relatively undisturbed ecosystems can radically change those 
ecosystems, especially when we consider the timescales over which 
evolutionary change occurs.  In order to allow for the free 
self-determination of other species, and to conserve biodiversity, we should 
be careful about moving plants from one ecosystem to another.  This does not 
mean supporting Monsanto's drive to co-opt ecological concerns in order to 
maximize its sales of Roundup by demonizing exotic plants.  (If we want to do 
this, we can start by poisoning all the people of exotic ancestry that stole 
the Americas and Australia from the 'natives.')
 
Rain


                
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