I like what you've asked.  Why do we see our 'altering' of the natural environment as intrinsically destructive?  Some questions that come to mind- I dont know how important they are-: "What would a local diet without 'imported food species' have looked like?"  "Is it wrong to 'import' food to a region where it doesn't normally grow?"  "What is the merit of returning to an 'indigenous diet', and is this even possible, considering the loss of TEKW and indigenous species?"  "What constitutes 'indigenous' species, considering many species were 'imported' by wind, birds, and sometimes even the indigenous people themselves from other regions?"    

I will comment and work on the exec summary you've started, on Monday afternoon.  Tuesday and Wednesday will have to be a lot of wiki-checking and e-mailing back and forth to get this precis looking presentable.  -MD