[LEPS-L:8051] Re: Extinct 'species'/How many years?

[Doug Yanega]

Micheal Gochfeld wrote:

>> Doug concluded:  so the lack of new records is not necessarily
>>convincing evidence of extinction. PROVING that anything, even a large
>>vertebrate, is extinct is (as those in Tasmania can attest) nearly
>>impossible.
>
>That's why in science we don't try to "prove" our hypothesis, rather we
>pose null hypotheses which we try to reject, recognizing that if we reject
>the null hypothesis it provides support for, but does not prove our
>underlying or alternative hypothesis.

BUT (and this was sort of my point) virtually no one who is a non-scientist
policy-maker finds hypotheses to be compelling. They tend to simply offer a
convenient way to dismiss the scientists and their concerns as meaningless
hand-waving, as is all too evident from the refusal to acknowledge the
reality of global warming. In the present topic, the parallel is "You want
this insect to be Listed as endangered? Then PROVE it." Then again, if we
could get all the legitimately threatened invertebrates in the US Listed,
it would virtually shut down the real estate industry, as I'd be surprised
if there's much turf left undeveloped that does not have SOMETHING on the
verge of being wiped out. It's called a "no-win" scenario.

Mike also wrote:

>How many years would one need to monitor these sites
>(late August visits) before accepting that the species is gone.

Here's a pertinent but scary anecdote: Back in the 1890's, Charles
Robertson did a faunistic survey of floral visitors in Carlinville,
Illinois. Among them were some 200 bee species, including one he described
from a single female visiting spicebush, Andrena lauracea. Some 80 years
later, Marlin Rice re-surveyed the bee fauna of Carlinville, Illinois
(whose complexion had changed considerably over that time), and found every
single species on Robertson's original list - including one more specimen
of Andrena lauracea, only the second specimen ever collected.
Given this, obviously even an 80-year gap is meaningless if there are no
serious attempts to rediscover something in the right time and place. Of
course, this would be different if it were a species that was *abundant* at
one point in history. I'd sooner believe the Tasmanian Wolf is still around
than I would believe that there are still Passenger Pigeons or Carolina
Parakeets hidden somewhere.

Peace,


Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California - Riverside, Riverside, CA 92521
phone: (909) 787-4315 (standard disclaimer: opinions are mine, not UCR's)
           http://entmuseum9.ucr.edu/staff/yanega.html
  "There are some enterprises in which a careful disorderliness
        is the true method" - Herman Melville, Moby Dick, Chap. 82



 
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