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<font size=3><b><i><u>Bob, one problem with your C4 thesis is that we
have C4 native species too. They behave in ecosystems as if they
were a part of the natural evolution of that system, which of course they
were. I have not seen evidence that the native warm-season grasses,
for instance, have begun to to be invasive problems in response to
elevated CO2.<br><br>
</u></i></b>At 04:10 PM 2/4/2008, Bob Beyfuss wrote:<br>
<blockquote type=cite class=cite cite="">Hi Bill <br>
Thanks for posting. These issues are worthy of discussion.
<br><br>
As long as there is international contact between nations there will be
introductions of pests, diseases and plants that affect native plants and
animals and alter currently existing ecosystems regardless of how
diligent we try to be to avoid them and I am not saying we should not be
diligent in this regard. There is nothing wrong in trying to
preserve the ecosystems and the plants that we currently enjoy. I guess I
question some of the means we are using. Our annual flu outbreaks,
which kill many people, are a good example of an annual unwanted and
unintended "invasive" pathogen introduction. We could probably
save many lives each year by simply not letting anyone into or out of
this country. It is naive to think that we can isolate ourselves or
our current ecosystems to become completely immune to the potential
biological threats from the rest of the world given the fact that we are
a global society. <br><br>
The question is "What do we do about this situation?"<br><br>
It seems that one of the politically correct approaches in the case of
plants is to label them with value laden, emotional terms like
"alien, exotic, invaders" and kill them using whatever methods
we want without really knowing the long term consequences of our actions
or bothering to investigate what the long term consequences of the
"invasions" may be. It is much easier to justify killing things
once they have been sufficiently demonized by rhetoric such as this.
"Wars" are difficult to support without mustering appropriate
propaganda. <br>
<br>
Certain plants labelled as invasive are what are known as C4 plants
because they utilize carbon dioxide differently and much more efficiently
than C3 plants. This certainly gives them an edge in this globally
changed climate with double the Co2. Couple this with human disturbance
as pointed out by Craig in the original post on Yellow Star Thistle that
started this dialogue and you start to see the root of the problem.
<br>
Craig wrote, <br>
"The article states that "It pushes out native plants",
but we have measured just the opposite interaction between the YST and
natives.YST only grows well, wherever the native understory has been
completely removed, like it has in 99% of lower elevation
California. Wherever you have a good density of native plant
understory, the YST is never any problem"<br><br>
So is YST the problem or is it the removal of the native
understory? </font></blockquote><br>
<b><i><u>ST is now the problem because it reduces drastically the
biodiversity of an ecosystem. Getting native species back into the
site is the answer to the ecosystem biodiversity problem. It
appears that at least part of the answer to getting native species back
in is controlling the YST (or saltcedar or cogongrass).<br><br>
What is your take on the value of biodiversity in natural
ecosystems? We're not talking about food production ecosystems
here.<br><br>
</u></i></b>Bill Stringer<br><br>
<br><br>
<blockquote type=cite class=cite cite=""><font size=3>Even a few degrees
warmer temperatures has profound effects on any plant species ability to
survive. Does anyone not think that the proliferation of Zone 6 plants
(USDA hardiness Zones) in Zone 5 is not related to climate change? The
link between climate change (higher Co2 and temperatures) and success of
invasive plants is really pretty obvious to most people who understand a
little about how plants grow. <br><br>
Chestnut blight disease reduced the % of American chestnuts in my local
forest here by 99% and at one time more than 50% of all the trees growing
here locally were American chestnut according to historical
records. The chestnuts were replaced by mostly Sugar maple trees
over the past 90 years or so. Is is fair to say that sugar maple
"destroyed" the previous chestnut dominated ecosystem? If you
can say that "destroy" means the same thing as
"alter" or "change" then that is indeed true. Was
this a good or bad thing? Well, I guess that depends on whether you favor
eating chestnuts or using maple syrup. These are human distinctions, the
forest remains as a forest. It will still be a forest even if it becomes
dominated by<i><u> Ailanthus altissima. </u></i>The sugar maple dominated
ecosystem may very well be replaced by an Ailanthus dominated ecosystem
but unless it all gets bulldozed, it will remain as a forest ecosystem.
<br>
<br>
Pathogens such as chestnut blight and pests like the hemlock Wooly
adelgid that usually kill their hosts present an evolutionary dead end to
themselves. We are already seeing American chestnut seedlings growing
back in some areas as well as some resistance to the hemlock wooly
adelgid. If a completely blight resistant strain of chestnut is
discovered should we clear cut all the sugar maple trees and plant back
the chestnuts in the name of restoration ecology? <br><br>
Western hemlock has evolved resistance to the "invasive"
adelgid pest on the west coast because the pest has been there for a long
time. In the 1980's NY State spent huge sums of money trying to first
quarantine and eradicate an imported pathogen called Scleroderris canker.
I still have filing cabinets full of bulletins on how to eradicate this
disease which turned out not to be a serious problem after all. How many
millions and millions of dollars have been spent trying to eradicate
gypsy moths? <br><br>
In retrospect, most will agree that these and many other specific
attempts to kill off the bad guys have resulted in huge wastes of money
and resources. I contend that 50 years from now most of our current war
on invasives will be similarly judged.<br><br>
<br><br>
<i> <br><br>
</i> At 01:09 PM 2/4/2008, Bill Stringer wrote:<br>
<blockquote type=cite class=cite cite="">At 11:41 AM 2/1/2008, Bob
Beyfuss wrote:<br>
<blockquote type=cite class=cite cite="">This is the best article I have
ever seen cited on this list serve. People <br>
need to wake up the the fact that virtually every ecosystem on this
planet <br>
is now dramatically different than it was even 50 years ago due to human
<br>
activity on a global scale. </blockquote><br>
<blockquote type=cite class=cite cite="">Efforts to "restore"
ecosystems that have been <br>
altered by irreversible global changes, such as doubling the carbon
dioxide <br>
levels in the atmosphere and rising temperatures, are a huge waste of
money <br>
and resources. Invasive plants are just one of the many symptoms of these
<br>
changes - </blockquote><br>
<blockquote type=cite class=cite cite=""><i>Invasive plants are clearly a
symptom of our willingness to import exotic organisms. <br>
I'm not so sure of the link between invasive plants and global climate
changes.</i> </blockquote><br>
<i>There's anthropogenic greenhouse gas increases, and then there's
introduction of<br>
<a href="http://www.cogongrass.org/">cogongrass</a> ,
<a href="http://www.nps.gov/ALIEN/fact/tama1.htm">saltcedar</a> , and
numerous other examples. These are different problems, <br>
and should not be lumped together under "huge waste of money and
resources" . </i><br><br>
<br>
<blockquote type=cite class=cite cite="">yet we declare "war"
on alien, exotic, species that "menace" us as <br>
though killing off these plants will somehow solve the
problem.</blockquote><br>
<i>Which problem, Bob, the Great Greenhouse, or Exotic invasive plants
that are <br>
documented to be destroying native ecosystems, and throwing the
bio-geo-chemistry <br>
out of whack.<br><br>
<br>
Tell that to American chesnut, and hemlocks.<br><br>
</i>Thanx<br><br>
Bill Stringer<br><br>
<br>
<blockquote type=cite class=cite cite="">At 10:06 AM 2/1/2008, Olivia
Kwong wrote:<br>
>
<a href="http://www.sciencedaily.com/releases/2008/01/080131101747.htm" eudora="autourl">
http://www.sciencedaily.com/releases/2008/01/080131101747.htm</a><br>
><br>
>Conservation Strategies Must Shift With Global Environmental
Change,<br>
>Ecologists Urge<br>
><br>
>ScienceDaily (Jan. 31, 2008) . Traditional ecosystems in which
communities<br>
>of plants and animals have co-evolved and are interdependent are<br>
>increasingly rare, due to human-induced ecosystem changes. As a
result,<br>
>historical assessments of ecosystem health are often inaccurate.<br>
>Scientists are now suggesting that efforts should focus less on
restoring<br>
>ecosystems to their original state and more on sustaining new,
healthy<br>
>ecosystems that are resilient to further environmental change.
Accepting<br>
>some permanent changes may increase health of ecosystems.<br>
><br>
>See the link above for the full article text.<br>
><br>
><br>
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opinion of the individual posting the message.</blockquote><br>
Bill Stringer<br>
Editor, Journal of the SC Native Plant Society<br>
PO Box 491<br>
Norris, SC 29667<br><br>
864 656 3527<br><br>
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