Hello Chris and all:
Several; haven't bothered to count, but most of my experience is in
Mediterranean ecosystems, primarily in Southern California, but some in
Greece and France (to a much lesser degree).
I may be having a little trouble understanding your point, but to clarify,
"colonizing species" means any colonization of a site not previously
occupied by a particular species, and it goes on all the time, in little
increments or large leaps, depending upon the mechanism of transport and the
suitability of the site for a particular species. One can call this
"invasion" too, if one likes.
I believe a close reading of my post will reveal that I would agree that
different species (ecotypes, even) "behave" differently in different
contexts, but beyond this, I'm not sure what you mean about "invasive plant
ecology." Such a reading also will reveal that I intentionally used
weasel-words, which I thought were an efficient and sufficient way of
communicating that I was not "promoting" any particular uniform rule.
I do not disagree that "eradication" can be theoretically useful, and in
some subset of the theory actually useful. However, I believe that it is
often the case that, unless one is operating on an unlimited budget that
money and other resources often can be better allocated, sometimes for the
very reason Chris cites, "it is virtually impossible to eradicate some
species." I, too, have often used the word "management" to avoid trapping
myself with "eradication." I have tried very hard to avoid using bullshit,
either figuratively or actually, but that's not always possible. I also
found "management" of restoration projects to be very, very difficult to
manage, and almost impossible to damnfoolproof. That goes octuple for
irrigation and fertilization--in most cases.
By "used" (I believe I did put "used" in quotes) I meant that I was reckless
about reintroducing propagules of all species that were present in the area,
including some alien colonizers, but in the case mentioned I did introduce
propagules of a particular new alien plant for a particular purpose, which I
had observed to be a "fast-fader" (non-persistent) in similar situations.
That's the way it turned out. The indigenous ecosystem simply was
better-adapted through evolution than the "invaders." That is, the invaders
dominated once they had time to reproduce and conditions ideal for their
germination, growth, and reproduction, but over time, with "patience," the
natives edged the aliens out--mostly.
The aliens did provide some benefits for the indigenous ecosystem, though
given my preference I would have used indigenous colonizing species (there
were some of these). The weedy annuals grew very quickly after the first
year (some mysterious allelopathic effect and perhaps a paucity of
propagules minimized their populations), dominated the cover the first and
second years, began declining the third year, and by the fourth and fifth
year were present in insignificant amounts.
That is, in this case (and several other later cases) the alien and
indigenous colonizing species did seem to validate some of the points made
in the Davis, et al paper.
Davis and others are well aware that the dogmas are out to bite them; they
are trying to objectively assess a multi-pronged phenomenon as honestly and
briefly as possible. I have yet to see a single biter actually cite text
from the paper and resolve the facts, errors, merits, and deficiencies
specifically therein. In the absence of something along those lines, I see
mostly indignant huffing and straw-armies.
WT
----- Original Message -----
From: "Chris Traft" <[email protected]>
To: <[email protected]>
Sent: Monday, July 18, 2011 9:14 PM
Subject: Re: [ECOLOG-L] New paper about "invasive species" debate
Hello Wayne,
What ecosystems have you witnessed "colonization" ecology in? Invasive
plant
ecology is different in different ecosystems, though disturbed landscapes,
landscapes highly managed by humans, or those close to human development
generally tend to be popular with most invasive species in most regions.
Also it depends on how well established the invasive plants are. I'll bet
promoting a healthy, native ecosystem and preventing further disturbance
may
prevent exotic species from establishing in a particular area. However, if
they are already well established and mature, or have completely taken
over,
you may need to employ some eradication (I prefer "management", as it is
virtually impossible to eradicate some species) methods. Also, what do you
mean, by "used?" Did you plant them, or harvest them for a particular use?
~Chris
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