I really don't agree with this... harvesting of passenger pigeons,
great auks, and dodos eventually led to thier extinction. I don't
think that habitat destruction was the main cause in these instances.
It is harder to overharvest plants, since usually a generation lies
in the soil as seed. However, I'm sure that there are examples of
local population destruction by collectors, ie. the collection of orchids
from urban parks.
I wouldn't let collectors off the hook just beause they're doing less
damage than the habitat destroyers :-) In fact, one could argue that
habitat is plowed under to help the economy and provide jobs (ie. a
"necessary evil")... collecting isn't nearly so necessary.
Michael Chamberland