just briefly Jerome I would like to connect this to complexity and diversity as essential traits of healthy biotic systems;  the loss of complexity is an entropic process i.e. is irreversible in that the status quo ante can never be restored.  over time a new complex order may evolve to fill the ravaged niche, but the original functioning system cannot be reproduced.  a renewal or renaissance of small town American culture may happen, but the new version will not replicate what was lost.  in some ways this might not be such a terible thing, as some of what was lost was not so wonderful, but there is also the issue of the enormous difficulty of recovering from the stripmined high-entropy state.

loss of complexity (monoculture, reduction of species count per acre) reduces overall biotic productivity and simultaneously reduces resistance and resilience in face of pests, adverse weather, etc.  this seems to be true whether the ecosystem is a reef, a farm, a town, a city, a compute cluster, a power grid, or an economy.  

monoculture equals increasing risk of single point catastrophic failure with poor/costly/slow recovery prospects.

the lesson I derive from this is that Wal*Mart is inherently a bad thing, and so are company towns.

The difference between theory and practise in practise ...