Sunday, November 02, 2008

Attempting to Begin Restoration Effort Assessments

During this recent growing season, I've tried to keep track of the species that I've identified growing throughout our entire 10 acres, keeping separate lists for the area east of the draw, west of the draw and for the back 5 acres. It's not a terribly scientific undertaking, in that I haven't done transects or any other statistical sampling method, but I have done my best to identify what I've seen.

[One disclaimer here: I'm identifying plants based primarily on wildflower guides (of which I have 6 that I use). That means that I may be misidentifying unusual species as more common ones. Then there's the issue that if the plant isn't blooming or seeding out, I'm probably missing it altogether. Sedges, especially, have been tough for me. I know I have several species of sedge scattered throughout the yard, but I have no guide that makes me feel at all confident about identifying even one of them.]

Recently I started reading a classic on prairie restoration, The Tallgrass Restoration Handbook. The authors in this book caution that there are few good remnants of tallgrass prairie left, therefore most restorations will begin with land that has been compromised in one way or another. So one of the first topics they cover is how to begin assessing what you are starting with, as a basis for deciding how to proceed with the restoration and for figuring out whether your restoration attempts are moving you in the direction that you want to be moving.

One of the assessment tools they talk about is called the coefficient of conservatism (C or CoC, depending on the source). This is a number from 0 to 10 that is assigned to native plant species based on, in essence, their weediness and desireability within a high quality prairie. A rating of 0 is a widely distributed, weedy species in no need of conservation; a rating of 10 is a rare (possibly endangered) species found only in high quality prairies.

Last spring, Brad Guhr (of Dyck Arboretum) kindly forwarded a list of the coefficients of conservatism for plants species found in Kansas. Last night I used this list to figure out the mean CoC for each of the 3 areas on which I've have been compiling lists. My statistical methodology, for anyone who should happen to care, was simply to look up the coefficient of conservatism for each of the species that I had listed, count the total number of species on the list for that area, then divide the former by the latter.

Using this method, the area east of the draw has a mean CoC of 2.21; the area west of the draw has a mean CoC of 2.31; and the back 5 acres (the area we burned this spring) has a mean CoC of 2.64. That puts all 3 zones firmly in the "Who the heck knows what to do with this plot" category. Seriously. Although, of course, they phrased it a little more elegantly in the book.

So far, the worst plant I've found on this site is Johnson grass (Sorghum halepense). Based on their coefficient of conservatism, the best plants I've found are spring ladies' tresses (Spiranthes vernalis, CoC 8), narrow-leaved milkweed (Asclepias stenophylla, CoC 7), white prairie clover (Dalea candida, CoC 7), and leadplant (Amorpha canescens, CoC 7).

Plus as I started reading this book, I found one big positive for our site that I had never considered before: the soil is basically intact. It has never been plowed, nor has it been subject to massive erosion or reshaping. Given that plus, I'm determined not to use the "Roundup the whole darn mess, plow it up, and start fresh with seed that you buy or collect" method of prairie re-establishment.

So for starters our negatives are
1) overgrazing,
2) introduction of exotics,
3) lack of burning for years,
4) overgrowth of shrubs, young trees, and weedy species, and
5) small site size.

As I read, I feel like I've been on the right track. So far I've been keeping grazing off (at least for now), burning, using Roundup selectively, and overseeding with desireable species. Especially in the area we burned, I know that quite a few species showed up this year that I didn't see last year.

It's reassuring to know that my instincts have been reasonably good so far. Now if I can just keep threading my way through this continuing maze....

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