John V. Calhoun
bretcal at gte.net
Mon Sep 29 17:51:24 EDT 1997
Dr. James Adams wrote:
I can think of reasons for such introductions,
> such as a species having historically occurred in an area where it
> has since been extirpated by humans. We would then be
> *reestablishing* populations that *should* exist. Do others agree?
I indeed agree. The reintroduction of the Schaus' Swallowtail onto
mainland Florida is a good example. HOWEVER, there is some speculation
that old records from the mainland do not indicate that resident
populations existed. Rather, they may have been strays from populations
on the Keys where the hostplants are native. The hostplant, torchwood,
may not be native to the mainland--again human intervention makes such
conclusions nearly impossible. More food for thought...
> One last point, however, that should be made is that such
> introductions are *going to occur*, even if totally regulated and no
> one purposely moves species around.
Definately. I suspect that some of the unusual records in Florida are
the result of such "helpful" movements. Papilio androgeus was possibly
accidentally introduced into South Florida during the mid-1970's. It
hasn't been seen in the region for some time so it appears that this
introduction did not take. Another likely introduction is South
American Electrostrymon sangala (the single Florida record was
incorrectly believed to represent E. endymion). Did it fly here on its
own--doubtful; like so many other insect species intercepted each year
by Customs at Miami and Tampa, it probably arrived as an incidental
result of human activities. However, PURPOSELY and irresponsibly
importing/moving extralimital species is another story...
> The modern age of human transportation has, by its very nature,
> muddied the picture of natural ranges/movements of an incredible
> number of species (including humans). I would hate to be an
> archaeologist of another species hundreds of thousands of years from
> now trying to put together clear pictures of natural ranges of
> species. Lets hope our informational resources last a long time!!
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