[APWG] Ecosystem Restoration and Weeds Re: Try and get reveg costs down, plus quicker, better quality

[Wayne Tyson]

APWG and RWG:

This is a very worthwhile discussion, and Dremann raises some interesting 
points. I have, for what they may be worth to participants, [[inserted 
thus]] my comments into Dremann's text below:


----- Original Message ----- 
From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
To: <apwg at lists.plantconservation.org>; <rwg at lists.plantconservation.org>
Sent: Monday, January 23, 2012 2:24 PM
Subject: [APWG] Try and get reveg costs down, plus quicker, better quality


> Dear Wayne and All,
>
> Thanks for your email.
>
> You wrote:  I'm not convinced that 98% or even 100% extirpation of weeds
> is possible, necessary, or even desirable.
>
> Unfortunately, and in California especially, and in other weed-infested
> areas  in North America like the cheatgrass fields of the Great Basin, it
> is best to have a goal of 98% or better native cover in your non-riparian
> projects within six months or less.

[[I agree in principle that it is best to have a goal of having an OPTIMAL 
number and diversity of indigenous species present in ecosystem restoration 
projects within six months or less, but I disagree that "cover" is the best 
measure; on the contrary, I believe that high cover is not only highly 
irrelevant at that stage of development (necessitating damagingly high 
populations and unnecessarily high costs), it can be significantly 
counterproductive. "More" is not only not better, high enough populations of 
even indigenous species at the early stages of ecosystem development can 
cause the system to crash. Species selection at this stage also is highly 
important; the quantity of some species should often be lower than survey 
data might, if not properly interpreted in the context of ecological 
dynamics, indicate. WT]]

>
> This goal is so you do not have to baby-sit a project for a decade, or
> replant it every year or two without any resolution in sight, like the
> project at http://www.ecoseeds.com/road.test.html or
> http://userwebs.batnet.com/rwc-seed//road.test.html

[[Any good restoration project should not require "replanting" (planting can 
be an important element of an ecosystem restoration project, but it is far 
from the only element). While re-treatment might be necessary for any number 
of reasons, I have found that the site disturbance involved in doing so 
commonly does more damage to the developing ecosystem than the "replanting" 
benefits it. WT]]
>
> This is also my conclusion after measuring hundreds of vegetation cover
> transects over long periods of time, and seeing that when even a few
> percentage cover of certain weeds gets into your native ecosystem or your
> native planting, can cause a lot of trouble.

[[I quite agree that a small population of weeds can "cause a lot of 
trouble," but it is easy to interpret an increase in weed populations as 
more troublesome that they sometimes are. When the goal is a dynamically 
stable, self-sufficient, self-renewing ecosystem, the long-term trend is 
more important than short-term, transitory phenomena. Weed populations can, 
for example, rise alarmingly in the second season, persist through the 
third, then go into decline in the fourth, becoming a minor element in the 
fifth. In the meantime, the weeds can actually be performing ecological 
services. WT]]
>
> The strong herbicide-like components that certain weed roots put into the
> soil, can cause the slow-motion collapse of your native ecosystem, and can
> cause local spatial extinction of your native understory.

[[I know that this concept is popular, but the evidence is thin, and there 
are too many variables involved to assign ecosystem decline to weed 
populations, especially with regard to "local spatial extinction" (if I 
understand the term "spatial" as intended by Dremann). I don't doubt that 
patches of weed monocultures can occur, but that is one of the rare 
instances where, when the project design and/or execution has been faulty or 
some other phenomenon causes damage to an otherwise well-designed and 
executed project, some interplanting might be in order--but only after the 
weed stand has demonstrated to be progressive (after the third or fourth 
season, in lower-elevation areas such as coastal California). WT]]
>
> Plus a lot of the weeds are in place in North America, because they are
> able to fill the niche that was once occupied by a native species.

[[While I agree that weeds grow in PLACES "once occupied by a native 
species," they do not "fill" niches more suitable for indigenous species. 
Weeds occupy such PLACES largely and most commonly DISTURBED (niche 
characteristics altered to the extent that the place has been changed into a 
"weed niche." PLACE does not alone constitute niche. The distinction is 
crucial! WT]]
>
> For example, the first weeds that colonized California during the Spanish
> Mission period, like the filaree and wild oats, were California native
> plant mimics, in that they were able to get into our ecosystems because
> their seeds mimicked the native seeds, with their awns.

[[Certainly, some native species have awns, and other characteristics in 
common with non-indigenous species, but this does not make them the same. 
For example (until the man who took over my business in 2000 took them or 
threw them away; he would never answer my inquiries) I once had photographs 
illustrating that oats, for example, were prevented from screwing themselves 
into the compacted soil where Nasella (Stipa) pulchra easily penetrated the 
thin desiccation cracks and created a healthy, Avena-free stand. Avena would 
be favored by a disturbed rather than a compacted soil surface in that case. 
WT]]
>
> Also weeds can get quickly established in native areas and able to spread
> quickly, if they are members of the same genera as the local natives--like
> the weedy European Vulpia grass taking the place of our native Vulpia
> species, or the exotic weedy clovers taking the place of the native
> clovers, or the weedy thistles like Italian and Yellow Star, taking the
> place of the native  members of the sunflower family that used to blanket
> our State each summer.

[[I'm not sure of the difference between the "indigenous" and 
"non-indigenous" Vulpia species, but I will leave that argument to the 
taxonomists and plant geographers--the last I heard was that some 
authorities thought that Vulpia was indigenous to both North America and 
Asia, etc., etc., but I simply don't know. Evidence? But this is only a 
single case of what could be a separate discussion. I don't doubt that there 
are cases where displacement of indigenous species has occurred; nay, I 
think it is quite common. I, too, decry the displacement of indigenous 
flowers and do not deny that exotics have come to dominate many wild areas 
to everyone's detriment. But I don't think they have done it all by 
themselves. Soil disturbances of many kinds, and continued livestock 
grazing, not to mention huge alterations in the vector picture, have all 
combined with the mere presence of weeds and their propagules to effect the 
phenomenon. But I believe that once the disturbances have been removed, and 
niche characteristics that once favored indigenous species more than weeds 
return, that indigenous species can gain the upper hand, as it were. WT]]
>
> So unless you knock the total weed cover back very quickly, as close to
> 100% gone as you can, within 3 months or less,  then you open the door for
> the weeds to reproduce and spread and continue to do their environmental
> damage over time.

[[Until about forty years or so ago, I would have said the same thing. "It 
just stands to reason!" The problem with common sense is that it tends to go 
off half-cocked, and I went off half-cocked on a lot of things for at least 
fifteen years until I finally purged myself of the agronomic and 
horticultural paradigms that I acquired from too much formal education and 
started de-schooling myself--looking at what Nature was actually doing 
instead of believing what the "authorities" claimed was fact. I learned to 
place more faith in Nature (God?), and stopped trying to invoke control 
based on my own biases.  WT]]
>
> I am voting for the Mark Vande Pol standard, which is less than 0.5% weed
> cover, and achieve that within three months or less.  That is my goal in
> my exsitu test plots right now.

[[I'm far more interested in populations and their health than I am in any 
kind of arbitrary standard. However, I must admit that such "standards" have 
much potential as a "full-employment act" for weed-bashers who are not very 
selective. WT]]
>
> Then, over the next three months or less, get 98% or better native cover,
> to hold the ground against future weed invasions or colonizations.

[[Without a healthy ecosystem in place, invasions can be expected to 
continue. WT]]
>
> Sincerely,  Craig Dremann (650) 325-7333
>
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WT