[APWG] Ecosystem Restoration Survey methods and sampling adequacy Re: 33 toe points adequate to sort an area into a category

[Wayne Tyson]

APWG:

Whatever the number of intercepts, anyone performing studies that lack a 
scientific basis will find it difficult to be considered credible by 
ecologists, other biologists, and statisticians. This does not mean any 
anyone is prohibited from doing anything he or she desires, it only means 
that a rather large and influential segment of the scientific community may 
not accept a procedure that doesn't meet scientific standards. Since it's 
relatively easy to meet such standards, I would suggest that subscribers to 
this list and others consider doing so, especially if one intends to spread 
the results around as if they were valid.

WT

PS: I have done "studies" that fell short of scientific standards myself, so 
I'm not being holier than anyone here. I kept such studies pretty much to 
myself and those actually involved in the study, and I certainly did not 
publish them. I had enough trouble as it was being disregarded by academics.

----- Original Message ----- 
From: "Craig Dremann - Redwood City Seed Company" <Craig at astreet.com>
To: <apwg at lists.plantconservation.org>
Sent: Friday, April 20, 2012 8:50 AM
Subject: [APWG] 33 toe points adequate to sort an area into a category


Dear Wayne and All,

Thanks for your email.  I have increased my minimum toe-points, from 30 to
33, so that the results are easily multiplied by 3, to get the percentage
cover of weeds, wildflowers and native grasses in a native understory.

My recommendation of 33 paces as being an adequate number of toe-point
paces to measure a grassland community, is based on going out and doing
those surveys.

Anyone could go out and do a 33 pace and a 50 pace and a 100 pace, and a
500 pace toe-point, and confirm and report back to everyone on this list,
that 33 paces is adequate, and this is the best time of year to do the
toe-points right now.

The purpose of the 33 pace toe-point is to get a rough idea of your
percentage cover of wildflowers, native grasses and weeds, and then put
your results for the site into one of five categories, that I have on the
webpage at http://www.ecoseeds.com/WMA.html as follows:

Poor condition, but with potential for future improvement=0-50% native
grass/wildflower cover, Fair=51-75%,  Good=76-90%, Excellent=91-99%, and
<As Good as it gets>=99.1 to100%.

If everyone can imagine, what I saw when I did my 100 pace toe-point
through Mark Vande Pol's grassland last summer---My first step, no weeds,
solid natives.  My second to 33rd step, no weeds, 100% solid natives.  My
34th to 100th step, no weeds, 100% solid natives.

You get a good idea by the 10th toe-point step, that you are walking
through an area that is going to fall into one of the five categories,
somewhere between Good and <As Good as it Gets>.   By the 33rd step, you
know you are between Excellent and <As Good as it gets> and by going the
100 paces, you can confirm that you have found the Promised Land of <As
Good as it gets>.

 If your percentages fall close to the borderline between two of the
categories, you may want to go further, like sorting out at Mark's if you
are between  <Excellent> or <As Good as it gets>.

However, if your 33rd pace has already sorted your site solidly into one
of the five categories, then you do not have to go further.

Our Weed management Area group is going to have a 33-pace toe point party
in Redwood City in our wildland serpentine grassland park, Stalstaf Park,
in May.

Sincerely,  Craig Dremann (650) 325-7333



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