Traffic in plants and plant seeds

[Kenelm Philip]

	Paul Cherubini asked:

> Am I correct in concluding that given the choice between planting
> eucalyptus or allowing the monarch habitat to wither away,  you all
> would vote for the latter?

	My posting on this subject was addressed to the _general_ case of
freely introducing exotic species--clearly not a good idea for those who
want to preserve biodiversity. In an earlier posting on this topic, I
remarked:

"Despite the cases where introduced organisms have been useful, the
overall picture is pretty dismal."

So I am willing to entertain the idea that some importations may be OK.
I was also under the (mis?) apprehension that the eucalyptus on the
California coast was aleady there, in which case the question is moot.
Obviously a few more aren't going to affect the overall situation--that
species has been in the state for some time now, I thought.

	It was also my understanding (not being a Monarch expert, I may
be wrong here) that the key factor making these coastal spots into Monarch
overwintering spots was the cool foggy climate. In fact, some of the
butterflies get trapped along the way in gullies at the foot of various
desert ranges, owing to local conditions of humidity. This means that almost
_any_ tree that will flourish in that climate will do--the Monarchs do not
need a specific tree. So, if the native trees are dying out, the problem
is what to replace them with. If this were in the past, I would recommend
looking for a native tree, if any can make it at these sites. Barring that,
one would look for a non-aggressive exotic tree. However, I gather (from
a talk by Paul Ehrlich) that very little of California's native flora is
now intact--in which case the damage has already been done, and bringing
in more eucalyptus may be insignificant.

	I have no quarrel in principle with bringing in a non-aggressive
exotic to save a native species. Either way you run a risk of damage--but
I would make sure that other avenues are well-explored first, and that
the import will be benign, as far as is known. The trouble is that ap-
parently harmless things have a habit of displaying unwanted behavior
down the road. These are _not_ simple problems...and the long-term record
of damage from both accidental and deliberate imports should  make anyone
pause for some careful thought.

	It's also clear that the actual decision should be made by well-
informed people at the site, rather than people thousands of miles away.
:-)

							Ken Philip
fnkwp at uaf.edu

P.S. My congratulations to Paul for inventing a new misspelling of my name!