Extinction vs accuracy

[John Shuey]

I can only go so long with chiming in on this conversation.  Without looking up anything, here is my take (from the perspective
of a conservation practitioner).  Also note that my grammar sucks in general, so that I may have missed some obvious points
below.
 
Extinction - a noun, describes a process that works at several levels - levels which therefore should always be specified when
using the term.
 
Extinct - an adjective, describes the status of an entity, such as a population, species, or group of species.
 
Extirpated, an adjective, similarly describes the status of an entity.  As I know the term, it is always applied to species in
the context of a definable geographic area. I have never seen this term used to describe single population sites.
 
So here's how they relate in my mind:
 
  -    At its most fundamental level, EXTINCTION is a population level process - populations are
       always at risk of extinction.  But in a functioning ecological landscape, new populations
       are generally founded at the same rate that populations become extinct, so the net effect is
       a wash (this would be a stable regional metapopulation).  In today's human dominated
       landscape, population level extinction often outpaces the founding of new populations.
 
  -    As localized population extinctions accumulate, a species may become EXTIRPATED
       from a defined geographic region.  For example, Mitchell's satyr was known historically
       from a single population in Ohio,  The extinction of that that butterfly from Streetsboro Fen
       resulted in the extirpation of Mitchell's satyr from Ohio. Karner blues were known
       from several populations in Ohio, all of which were extinct by the late 1980's  resulting in the
       extirpation of Karner blues from Ohio (note that it has been re-introduced to Ohio,
       which doesn't negate the fact of past  population-level extinction nor of past regional
       extirpation).
 
   -   As population-level extinctions further accumulate, a species may become EXTINCT - no living
       individuals survive.  A single population-level extinction resulted in the extinction of a species,
       the Dodo.  Hundreds, of not thousands of populations of the Wabash Riffelshell Mussel
       became extinct, ultimately resulting in the extinction of that species.
 
  -    As groups of species become extinct, the term is often applied to even larger taxonomic
       groupings.  For example, millions of populations became extinct, resulting in the extinction
        of hundreds of species, and now all dinosaurs are extinct (except maybe those pesky birds).
 
If these terms are used properly, (especially relative to the subject of the discussion), they can be very accurate terms with
little or no ambiguity.
 
 --
 
John Shuey
 
 
 
 
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