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<DIV><FONT face=Arial size=2>APWG:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Another option is to interplant indigenous species
that are known to be capable of suppressing weeds, either as part of a
"one-stroke" (transformational) restoration operation or as a two+ phase
(transitional) one. In both cases I prefer sterile, relatively short-lived
indigenous "pioneer" species so that they won't continue to suppress indigenous
species or reproduce; of course, there are always exceptions, depending upon
circumstances. I have even been known to use certain alien species for
specific functions that I know to be what I call "fast-faders" which do not
persist beyond their period of usefulness. By planting such transitional
suppressors/habitat modifiers in modest populations with space between them
being occupied by other indigenous species, such as slower-growing components or
even other pioneer species, most weedy aliens will find it tough going and
decline. After all, most aliens are not as well-suited to an undisturbed
ecosystem (hence Ewel's criterion of non-invasibility), they will similarly be
not so well suited to a recovering one--to a degree roughly proportional to the
state of recovery. A downward overall trend of alien population
populations and an upward trend of indigenous populations (though populations,
per se is not so important as diversity), is the best indicator of restoration
project status or success. Measures like "cover" can be misleading, and are
related to the site's productive potential and/or transitory or fluctuating
environmental state, not necessarily restoration project success. Cover is the
easiest thing to achieve; a fully functional, reproducing, diversifying,
self-sufficient, permanent biological complex may have a high cover value, but
in sites with limited productive potential or carrying capacity, too high a
cover value can lead to failure, particularly in arid or otherwise limited
sites. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I like Imlay's idea of the straw patches because my
first rule is heterogeneity as opposed to homogeneity, even on sites that appear
to be homogeneous, such as grasslands. Dremann's idea of using indigenous
(Nasella/Stipa, in his case) straw is an intriguing one, but I would steer clear
of the oats, which can have their own "allelopathic" effects. I would, however,
only use methods, straw included, that were both most effective and economical.
If restoration is too expensive, it will never become popular or widely used.
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In general, I am less concerned about "competition"
and more concerned about cooperation and interaction among species and do not
want 100 percent of anything (even though I would very much like for alien
species to be zero percent, I would not insist upon it; reducing them to a minor
component of the species assemblage and with a declining trend-line is good
enough for me. I want to restore the entire web of life that existed prior to
disturbance and/or as complex an association as the site conditions, sometimes
intentionally modified for that purpose, as I can get. For example, I want
"grassland" geophytes as well as the entire suite of grass species that made up
the original undisturbed site, if possible. In grassland sites, as with other
sites, it may take time to reach the levels of complexity and productivity that
existed before the disturbance. In areas where biological soil has been removed,
for example, part of the restoration strategy will have to include or even
emphasize soil-building processes, which can take many years. As the
initial restoration project changes habitat conditions, species which might not
have survived in the beginning can be added as conditions become more
suitable for them. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Of course, if natives can move back in on their
own, so much the better. I have always begun a restoration potential assessment
by considering the zero option--what is likely to happen if nothing is
done--then working into increasing levels of complexity until only a barely
sufficient level of action, resources, time, and money are used. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>As to herbicides, I have never used them, but that
doesn't mean that a very limited and highly directed application might not be
called for. I would never spray any herbicide where any chance of its touching
anything (soil or other vegetation) other than the target plant would be
possible. Selectively killing with herbicide without general spraying is nearly
always preferable to digging and otherwise disturbing the soil. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>WT</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ialm@erols.com href="mailto:ialm@erols.com">Marc Imlay</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=landrest@cox.net
href="mailto:landrest@cox.net">'Wayne Tyson'</A> ; <A
title=apwg@lists.plantconservation.org
href="mailto:apwg@lists.plantconservation.org">apwg@lists.plantconservation.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, November 16, 2012 4:06
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [APWG] Ecosystem dynamics
and 100 percent suppression by strawapplication Allelopathic straw keeping
weeds out & moisturein duringdrought</DIV>
<DIV><BR></DIV><!-- Converted from text/plain format -->
<P><FONT size=2><FONT face=Arial size=3><STRONG>One option is to use the straw
application on the worst, and relatively small, patches of invasives, and
use less harmful traditional treatments around the severely treated spots
so that natives can move back in over a five or ten year
period. </STRONG></FONT></FONT></P>
<DIV><FONT size=2><FONT face=Arial
size=3><STRONG></STRONG></FONT></FONT> </DIV>
<DIV><FONT size=2><FONT face=Arial size=3><STRONG><SPAN
class=703494011-16112012><SPAN class=109371913-03022012><STRONG><FONT
face="Times New Roman">Marc Imlay, PhD,<BR>Conservation biologist, Park Ranger
Office<BR>Non-native Invasive Plant Control coordinator.<BR></FONT></STRONG><A
title=blocked::mailto:ialm@erols.com href="mailto:ialm@erols.com"><FONT
title=blocked::mailto:ialm@erols.com face="Times New Roman"><STRONG
title=blocked::mailto:ialm@erols.com>ialm@erols.com</STRONG></FONT></A><BR><STRONG><FONT
face="Times New Roman">Natural and Historical Resources Division<BR>The
Maryland-National Capital Park and Planning Commission<BR></FONT></STRONG><A
title=blocked::http://www.pgparks.com/ href="http://www.pgparks.com/"><STRONG
title=blocked::http://www.pgparks.com/><FONT
face="Times New Roman">www.pgparks.com</FONT></STRONG></A><BR></SPAN></SPAN></DIV>
<P><BR></STRONG></FONT><BR>-----Original Message-----<BR>From: APWG [<A
href="mailto:apwg-bounces@lists.plantconservation.org">mailto:apwg-bounces@lists.plantconservation.org</A>]
On Behalf Of Wayne Tyson<BR>Sent: Wednesday, November 14, 2012 4:37 PM<BR>To:
apwg@lists.plantconservation.org<BR>Subject: [APWG] Ecosystem dynamics and 100
percent suppression by strawapplication Allelopathic straw keeping weeds out
& moisturein duringdrought<BR><BR>I have never seen 100 percent
suppression of vegetative growth by anything, much less straw. I once
concluded (erroneously) upon seeing a highly disturbed site "full" of the
"worst" possible assemblage of alien weedy species I had ever seen, that it
was "100 percent" devoid of any indigenous species after conducting a very
cursory but pointed point/quadrat survey of the area, I soon discovered how
wrong I was. Down between the weedy species I started finding small stands of
"re-invading" indigenous species, successfully slugging it out with the weeds.
Where these stands occurred, the invasives were clearly suppressed or entirely
absent.<BR><BR>If Dremann cannot or will not cite the specific mechanisms of
action relevant to the particular project he cites, I must continue to suspend
belief until he supplies more evidence. I find his direction to a website
insufficient to support his claims; moreover it is patronizing. I am well
aware of the suppressive action of "shade," "robbing water," and "robbing
nutrients," but am aware of no chemical action which has been demonstrated to
be any percent effective in suppressing any weed growth, much less 100
percent. I stand ready to be corrected and educated, based upon evidence and
directly relevant scientific/scholarly/disciplined research. "Many" does not
reveal what mechanisms of action are responsible for the claimed 100 percent
suppression of the species Dremann mentions.<BR><BR>I do agree with Dremann
that "straw," including that of standing or prostrate alien species, can be
protective of surface evaporation as well as contribute to water infiltration
and other beneficial effects. However, the presence of any straw can have
adverse effects upon emerging vegetation as well. For example Robinson (????)
studied this effect upon Stipa (Nasella) pulchra (dissertation at the
University of Oklahoma, if my memory serves me correctly), and found that
Stipa seedling survival was very low under such conditions. This, combined
with our own observations, led us to develop the technique of planting very
small seedlings in small colonies into the weed-infested areas. The colonies
expanded, albeit slowly, in our experimental plots. We were never able to
finish the large-scale project. We developed a unique planting method that was
very cheap (as were the small seedlings), and, in terms of actual long-lasting
results much more effective than mass-sowing, using far less seed, thus
minimizing the depredation of wild stand seed stocks by over-collecting. As
this work was never properly completed, we never published on it; however, we
did mark the plots with buried iron markers that could probably be located
with a metal detector today, some 32 years later, should anyone be interested
in a follow-up.<BR><BR>WT<BR><BR>----- Original Message -----<BR>From: "Craig
Dremann - Redwood City Seed Company" <Craig@astreet.com><BR>To:
<apwg@lists.plantconservation.org><BR>Cc:
<craig@street.com><BR>Sent: Tuesday, November 13, 2012 1:10
PM<BR>Subject: [APWG] Allelopathic straw keeping weeds out & moisture in
duringdrought<BR><BR><BR>> Dear Wayne and All,<BR>><BR>> Thanks for
your email. I will comment below your email:<BR>><BR>> Wayne--The
grass-straw mulch is an interesting idea, and I certainly<BR>> don't doubt
that such a practice might have some utility in<BR>> suppressing weeds, but
I am concerned about suppression of indigenous<BR>> species as
well.<BR>><BR>> Craig--Native grass and wild oats straw are being used
on a site that<BR>> has been 100% devoid of any natives for the last
12 years of<BR>> monitoring, and you can see a painting of the site at <A
href="http://www.ecoseeds.com/art3.html">http://www.ecoseeds.com/art3.html</A>.<BR>>
Since the straw is 100% effective against annual weed grasses like<BR>>
cereal rye, Medusahead or cheatgrass, plus annual thistles like<BR>>
Italian and Yellow Star, I do not recommend straw to be used in areas<BR>>
where native seeds might still be in the soil seedbank.<BR>><BR>> I
wonder just which "allelopathogens" are responsible for the observed<BR>>
effects? What is their mechanism of action?<BR>><BR>> There are
many Journal of Chemical Ecology articles an<BR>> allelochemicals,
that you can access through <A
href="http://scholar.google.com">http://scholar.google.com</A><BR>> and Dr.
Liu and his team have been important authors since the early<BR>> 1990s
studying the allelochemicals involved. His work was the first<BR>> to
sort out the allelochemical effects from the other plant<BR>> suppression
effects, like roots robbing water, or stealing nutrients,<BR>> or shading
of one plant by another, etc.<BR>><BR>> Since most of the USA is in
severe drought mode again, that you can<BR>> see at <A
href="http://droughtmonitor.unl.edu/">http://droughtmonitor.unl.edu/</A> the
straw mulch is keeping the<BR>> soil surface moisture in place for much
longer, perhaps twice as much<BR>> moisture today--while we have a dry 40%
relative humidity, barometer<BR>> reading 30.20 inches (no rain for a
while), and no dewfall at<BR>> night--than in areas that do not have
any mulch.<BR>><BR>> Sincerely, Craig Dremann (650)
325-7333<BR>><BR>><BR>><BR>><BR>><BR>>
_______________________________________________<BR>> PCA's Alien Plant
Working Group mailing list<BR>> APWG@lists.plantconservation.org<BR>> <A
href="http://lists.plantconservation.org/mailman/listinfo/apwg_lists.plantco">http://lists.plantconservation.org/mailman/listinfo/apwg_lists.plantco</A><BR>>
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