[APWG] Ecosystem restoration and alien species eradication Re:Performance standards to get weed-free and 100% native

Fri Aug 14 12:55:46 CDT 2009

Hi,

Guess I'm one of the "lurkers."

I've been following this conversation because in 2006, the board of
selectmen in Swanzey, NH, sold the topsoil of 5 conservation acres running
beside a river to a builder. Part of the land had been a gravel pit 30 years
ago; pioneer trees like pine and gray birch were repopulating the land.
Invasive glossy buckthorn and Tartarian honeysuckle were growing along the
river. 

In return for the topsoil, the town received 4 adjacent acres with a
conservation easement; the topsoil was removed from that land too. The land
would be storm mitigation for the builder.

The second part of the contract was the builder would build a dirt road onto
the property with a turnaround and parking lot so that people could put
their canoes or kayaks into the river.

Finally, the builder seeded the gravel with an assortment of plants; most of
what is growing is clover.

Of course, with no topsoil, Japanese knotweed has established on the dry
sunny areas; purple loosestrife is growing in the mitigation area and
culverts.

The Conservation Commission is going to spray Round-up on the knotweed; they
haven't noticed the loosestrife. However, I know enough about knotweed to
know that won't work. 

And that is why I am following the conversation.

Grace Lilly (another amateur)
Swanzey, NH

-----Original Message-----
From: apwg-bounces at lists.plantconservation.org
[mailto:apwg-bounces at lists.plantconservation.org] On Behalf Of Wayne Tyson
Sent: Friday, August 14, 2009 1:46 AM
To: apwg at lists.plantconservation.org
Subject: [APWG] Ecosystem restoration and alien species eradication
Re:Performance standards to get weed-free and 100% native

Craig and all:

It appears that other subscribers aren't interested in this topic, but I 
think we should continue it anyway, in the hopes that a few will get 
interested, or that it will stimulate "lurkers" to think about it. While I'm

greatly looking forward to a possible visit to your project and discussing 
the particulars with you in depth, I suggest that we owe it to the 
subscribers of this list to iron out the issues that each of us has raised 
one at a time. I'll be interested in your ideas about this and those of any 
who care to join in.

Let's again revisit the issue of the importance of well-coordinated 
restoration with eradication programs. You and I agree on this, I believe, 
but perhaps there are others on the list who think that restoration is 
unnecessary or irrelevant.

I hope that all who may not agree will post their ideas on this particular 
subject and that the discussion sticks to this one subject before moving on 
to digressions. I am very interested in where subscribers to this list stand

on this subject. The only way I know to interpret their silence is to 
presume that they agree and see no need for discussion or that they don't 
want to discuss it for other reasons.

WT

----- Original Message ----- 
From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
To: <apwg at lists.plantconservation.org>
Sent: Wednesday, August 12, 2009 12:23 PM
Subject: [APWG] Performance standards to get weed-free and 100% native

Dear Wayne and All,

I want to start my reply, to wax poetically about how nice walking through
a restored, a weed-free North American native ecosystem can be.

It is like visiting the Promised Land, a fairy tale land that people talk
about at annual wildland weed meetings--what would an area look like, that
they have been weeding for years or decades, if it was not only weed free,
but was 100% covered with the original pre-Columbian native ecosystem
understory?

The Shaw property is like a flawless 74-acre diamond, currently set in an
unending ocean of almost a 100% solid exotic understory of over 1,000
species of weeds, going 250 miles to the North, 200 miles to the East and
600 miles to the South, to the Mexican border.

===============

Wayne wrote:
Mowing before seed-set is a reasonably good practice in some contexts, it
may not always be practical (e.g., 2:1 slopes, etc.).

Reply:  99% of lower elevation California is gentle slopes to fairly flat,
so the level to gently sloping wildlands should be converted first, while
there are still viable native seeds in the soil seedbank.

If the native seeds in the soil seed bank are already 35-100 years old, my
big concern is we will not get started in this conversion back to 100%
native cover process, in time to take advantage of the viable native seeds
that are lying dormant underneath the exotics, before they lose their
viability.

The clock is ticking for these native seeds lying dormant in the soil
seedbanks, waiting for us to pay attention to them within our and their
lifetimes, otherwise their lives will be lost forever.

===============

Wayne wrote:  Once a site has been dominated by weeds for a year or two,
not to mention decades or centuries, there is a considerable buildup of
dormant seeds in the soil's seed bank. Mowing can't get those, nor can it
get all of the standing crop.

Reply:  Mowing absolutely must to get the standing crop of weed seeds
before they ripen, for that year, and contrary to popular belief, you do
not have to be concerned about the dormant weed seeds in the soil.

What has been happening over the last decades or hundred years, is that
the percentage cover of the weeds tipped the balance, where the weed
densities were able to use allelopathic chemicals to suppress the
germination of the dormant native seeds in the soil.

See Journal of Chemical Ecology, especially Dr. Liu's 1994 and 1995 papers
on a method to study plant-produced allelopathic chemicals  as an
independent plant suppression system, separate from competition for water,
nutrients, sunlight, etc..

Where the concern should be focused, instead of the weed seed bank, is
managing and resurrecting the native seeds in the soil seedbank, and once
you cross a percentage native cover threshold, the natives will start
permanently suppressing the weeds still viable in the soil.

Those weed seeds will remain alive underneath the natives for a long, long
time, but once you get the right densities or the right local natives in
place, the natives will suppress the weed seeds from every germinating
again, the weed seeds will eventually die in the soil.  Weeds Rest in
Peace.

=================

Wayne wrote:

Then there's the issue of the thatch/chaff, post-mowing regrowth, and
other specifics that raise questions.

Reply:  Thatch is not a problem. Fortunately most of the weeds that cover
California are annuals, but for the perennials that might regrow,  is
where a little brushing of the cut surfaces with Roundup might be
necessary, like Pampas grass, Harding grass, etc.

=================

Wayne wrote:

Not only that, but the vital importance that such treated sites must
self-sustain rather than be continuously treated for eternity.

Reply: That is why for the Performance Standards that I am recommending
for restoration of California perennial native grassland habitats, on my
web page at http://www.ecoseeds.com/standards.html is that you need to
make the conversion from exotic cover, back to at least 95% native cover,
within 90 days or less, with no future maintenance.

If you have to weed after the 90th day, you need to do your small scale
test plots over, until you get the right native cover that stops the weeds
cold.  It is like a poker game, you have to lay down your Royal Flush of
local natives, to beat the local weeds.  You do not want to have to keep
playing hand after hand of weeding-poker to eternity.

The only maintenance that might have to be done after the 90th day, is to
add more local native species to increase the diversity, and to fill in
gaps where native plant understory families have been catastrophically
exterminated, like California and the West.

Sincerely,  Craig Dremann (650) 325-7333

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Any requests, advice or opinions posted to this list reflect ONLY the
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