[APWG] Ecosystem Restoration Mathematics and performance Re: Mathematical Constants for annual, biennial weeds and natives

[Wayne Tyson]

I hope Dremman will go into more detail on his theory and its testing.

I have dabbled in this stuff a bit, but variables and the GIGO factor kept 
the predictability somewhere between low and dangerously misleading. The 
last thing we want to do in restoration is to lead ourselves down the garden 
path of pseudo-mathematics, eh?

When I retired, SERCAL was kind enough to let me spout off at their annual 
meeting, and I published a summary of remarks in Ecology and Society 
http://www.ecologyandsociety.org/vol5/iss2/art5/

I have submitted an "idea" to the Smithsonian Institution's Encyclopedia of 
Life group to gather and store in easily retrievable and "manipulatable" 
form, data on the range of requirements and tolerance limits for organisms. 
You can go to their website and submit any relevant idea. I hope Dremman 
will do so.

WT

PS: I developed a program for calculating the relative amounts of seed 
required for effective ecosystem restoration back in the 90's, but it relied 
more on feedback from actual projects that complex mathematical formulae, 
but it at least minimized one of the major errors in seeding ecosystem 
restoration sites--too much seed and an imbalance of species. This was 
necessity borne of error, from projects that, while I considered them 
"failures," did produce results that pleased others, they did not meet my 
own objectives. Many of my own mistakes in the early part of my practice 
were caused by TOO MUCH "success," but at the expense of the kind of 
diversity that the project was designed for. A very critical aspect of 
ecosystem restoration project performance is how plants (and, to some 
degree, animals, but that is a factor best left alone--but factored into the 
design) developed in relationship to each other. It is counterintuitive, I 
know (much of ecosystem restoration design tends to be counterintuitive, 
especially for designers that work from agronomic or horticultural 
paradigms), but if one must err when it comes to the amount of seed, it is 
best to err on the low side than the high side. And sometimes, this seems 
absurdly low to agronomists and horticulturalists. One must, however, factor 
in the best survivorship curves, growth rates, etc. to arrive at the best 
possible volume of seed. With some seeds, a quarter-pound per acre has 
proven to be 'way too much, and the result was suppression of many of the 
other species, resulting in lowered diversity, resilience, and overall 
performance at, ironically, much higher cost. There's a lot more to this, 
but I'll stop here. Bottom line: Guesswork is ok, based on a lot of 
experience (I screwed up a lot for fifteen years before I started to get it 
right), but it has to be good guesswork. Mathematical formulae are just 
fine, but unless they are close to perfect, the highly variable nature of 
Nature will confound them.

----- Original Message ----- 
From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
To: <apwg at lists.plantconservation.org>
Cc: <craig at astret.com>; <craig at ecoseeds.com>
Sent: Saturday, September 22, 2012 8:33 AM
Subject: [APWG] Mathematical Constants for annual, biennial weeds and 
natives


> Mathematical Constants for annual, biennial weeds and natives
>
> For those of us going out in 2013 to manage annual and biennial weeds,
> there is a concept that might be useful--Mathematical Constants.
>
> By measuring the interactions between the annual or biennial weeds, and
> local native perennial plants, you can assign a number from 1 to 100 for
> each species of weed and native plant.  Plants with a rating of <one> are
> the weakest weeds, and those with the mathematical constant of 100, are
> the most difficult to manage.
>
> Then, like a poker game, you use the local native species that has a
> higher mathematical constant number, to permanently replace the weed that
> has a lower number than the preferred native.
>
> For example, Yellow star thistle only rates a 5 on the 1-100 scale, which
> means that there are a whole lot of native plants that could be planted to
> permanently replace that weed.  This concept is especially useful to rate
> the invasiveness of weeds, that appear to be spreading rapidly, like
> Yellow Star thistle, or cheatgrass.
>
> When you measure their interaction of the weeds vs the local natives, you
> may find that weeds like cheatgrass are only default weeds, only growing
> where the native cover is absent, and that by planting back any amount of
> native cover, can permanently cure those weed problems.
>
> The most valuable use of Mathematical Constants, is to be able to
> determine the proper percentage of each species, for example for
> replanting after a construction project.  The amount of cover that each
> species takes up in ecosystem, produces a mathematical constant.   It is
> like making a list of ingredients and amounts of each ingredient, when you
> are baking a cake.
>
> A cup of native perennial grasses with a cup of native sunflower family
> members, and three tablespoons of native bean family members, etc.
>
> And each species is linked together, like a web.  If you decrease the
> percentage cover of  one species, then other species percent cover will
> have to increase, but you need to know what those links are, that keep the
> ecosystem holding together as one piece of cloth.
>
> And a most interesting and elegant thing, is that those links can be
> written as mathematical equations, and then you can use those equations to
> write a computer program to predict the ultimate cover of each species,
> when you change the percent cover of a single species.   I uncovered the
> potential of those mathematical equations almost 20 years ago, while
> working on native grasslands here in Central California.
>
> Most ecological restoration projects required by government agencies, like
> replanting pipeline right of ways after construction, or replanting gas
> well pads, or mine tailings, or new highway construction road sides,
> require the contractors to plants natives, and the project specs tell you
> to sow X, Y, Z species at so many pounds to the acre.
>
> However, those seed mixed have not been developed using the Mathematical
> Constant concept, and they are usually never pre-tested in small scale
> test plots to see if they will actually work.
>
> When you use native plants for restoration, it assumes that you want to
> permanently replace the weeds in the area with plants that are locally
> native.  Over the last 40 years of watching both restoration and weed
> projects, there is rarely any small scale test plots planted prior to the
> big project, to see if the natives you want to use will really work.
>
> And for the weed projects, planning is almost never done to choose the
> local natives you want to grow in the place of the weeds, because we get
> so focused on the weeds, instead of looking at and restoring the whole
> native ecosystem that we are working in.
>
> I hope that this concept of Mathematical Constants for weeds and native
> plants, is useful, and whenever you start a restoration or weeding
> project, look for and keep in mind that these interactions exist, and that
> they may be used to your benefit, to produce a much better result.
>
> Sincerely,  Craig Dremann (650) 325-7333
>
>
>
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