Hi, Conchlers. A few days ago I pointed out that collectors CAN threaten the
existence of species, usually in cases where the species' population has
already been lowered for other reasons. Unfortunately, when everyone knows
that a species has become rare, the pressure to collect it, either for
profit or simply to fill that gap in the collection, can actually increase.
Here's an example from the butterfly world:

"A third activity [after the big two, habitat destruction and pollution]
capable of harming butterfly populations is the continued killing of rare
and local butterfly species by some immoral collectors. A particularly
tragic case is Mitchell's Satyr [Neonympha mitchellii]. In the northeast
[USA] this butterfly was limited to a few fens in northern New Jersey, but
this butterfly has now been extirpated by relentless collection pressure.
One major colony was wiped out almost singlehandedly in the late 1970's by
an individual who returned to the fen daily during successive seasons and
each day killed every Mitchell's Satyr he saw. Even when collection pressure
doesn't result outright in the demise of a rare colonial butterfly, each
individual killed results in the depletion of the gene pool, and this loss
of genetic diversity becomes more important as the colony becomes smaller.
Each individual killed might have been the individual that contained a
mutation that would have allowed the colony to survive the inevitable
drought or epidemic that it will face.

"...Toward the end, even chain-link fences, guard dogs, and a security man
could not keep the poachers out."

(Jeffrey Glassberg, 1999, Butterflies through binoculars; The East: New
York, Oxford University Press, x + 246 pp. Quoted from pp. 30, 32, 137. Page
31 lists 27 butterfly species from eastern North America whose populations
have declined severely in the past 25 years, mostly from habitat destruction
and pollution.)

Although Glassberg was discussing the local destruction (extirpation) of a
species rather than its extinction everywhere, be assured that such
extirpations can very seriously lower the overall species diversity of an
area -- for instance, Britain, whose butterfly diversity has plummeted since
the beginning of the Industrial Revolution, for all sorts of reasons.

And you can define "extinction" as being simply the last extirpation of
many. It is remarkable that a single person can have the power of life and
death over an entire species. Surely every collector should be aware of
this, and collect wisely and moderately. People who collect species that are
on the verge of dying out should be treated as if they had shot one of the
last Whooping Cranes, and for the same reasons.

Bird fanciers have not collected specimens of birds or eggs for about a
hundred years, yet birdwatching is very popular. Some butterfly fanciers now
collect photographs of living butterflies rather than actual specimens. The
result has been a great increase in the appreciation of birds and
butterflies as living organisms with interesting behavior. Probably this
will happen eventually with mollusks as well, though I must agree with
Augustine when he prayed to God to stanch his raging passions: "Please, but
not yet."

Andrew K. Rindsberg
Geological Survey of Alabama