This project followed about fifteen years of failures "using" native plants;
that is, learning what not to do and how not to do it. The project depended
heavily upon shredding existing vegetation with special equipment modified
from an Austrailian shale-breaking machine, producing a very "stringy"
product rather than "chips." The ecosystem type was Southern California
Mediterranean (8-10 inches average annual rainfall), and the plant
communities were "coastal sage scrub" (aka "soft chaparral") and coastal
chaparral associations along with some coastal prairie associations, and,
importantly if not critically, cryptobiotic soil-crust associations. I no
longer have the data (the ecologist who took over my business did not return
it after he ran out on his contract), but some of the species included
Heteromeles arbutifolia, Rhus integrifolia, Malosma laurina, coast manzanita
(forgot genus and species--Xylococcus ?), Artemisia californica, Nasella
lepida, Nasella pulchra, Dichondra occidentalis, Eriogonum fasciculatum,
Lotus scoparius (common indigenous colonizers), liverworts, true mosses,
lichens, club-mosses, various blue green algae (now ? ). The exotic plant
seeded (Trifolium fragiferum) was used primarily to assuage engineer-fears
about erosion, but this project demonstrated how useful non-progressive
erosion can be (although there was very little soil loss). Some "native"
(but not necessarily indigenous) plant were also used, including
Eschscholtzia californica, "owl's clover" (? ?), a hemiparasite that helped
to reduce exotic grasses and forbs like Bromus sp. and Brassica sp.) Most of
the species arose from propagules contained in and on the
biologically-active surface soil mixed with the shredded vegetation (which
also contained propagules). I later learned how to use relatively sterile
subsoil and build soil organic material quickly, largely through the use of
"exotic" annuals that were not persistent.
As you know, habitat characteristics are importantly modified by the biota,
but the substrate was largely Torrey sandstone and stadium clongomerate or
Linda Vista formation. The site consisted of roadside right-of-way 1 1/2: 1
cuts and fills. The applied salvaged material was intentionally mixed,
including stones, roots, stumps, and other natural detritus. This material
was sheep-footed and track-walked into the prepared subgrade. The objective
was to produce a rough surface.
Please provide the text that led you to believe that I said that "indigenous
flora and fauna not evolving under such disturbance regimes as those that
support colonization by invasives". I don't think evolution figures into
what I said at all--not that it's not an important consideration; certainly
selection processes are operating. Neither did I say that there were no
"indigenous habitats that support flora and fauna that are dependent on
disturbance to maintain themselves." Please do elaborate as necessary to
clarify, and specifically state whether or not you misquoted me, including
reference to our specific remarks and how your interpretation and mine are
either inaccurate, misleading, or accurate and why.
WT
----- Original Message -----
From: "Kirkland, Melissa J NWP" <[email protected]>
To: <[email protected]>
Sent: Thursday, July 28, 2011 3:17 PM
Subject: Re: [ECOLOG-L] Ecology Colonization Re: [ECOLOG-L] New paper about
"invasive species" debate (UNCLASSIFIED)
Classification: UNCLASSIFIED
Caveats: NONE
Wayne,
This is an intriguing narrative. Can you provide more specifics? I'd
like
to know which species you used for restoration? What were the habitat
characteristics of the restoration site, and what native plant association
was present that you have observed to be so resistant to invasion in this
case?
As to your statement about indigenous flora and fauna not evolving under
such
disturbance regimes as those that support colonization by invasives, there
are indigenous habitats that support flora and fauna that are dependent on
disturbance to maintain themselves. If you would like further
information, I
would be happy to elaborate.
Melissa
-----Original Message-----
From: Ecological Society of America: grants, jobs, news
[mailto:[email protected]] On Behalf Of Wayne Tyson
Sent: Monday, July 18, 2011 1:08 PM
To: [email protected]
Subject: [ECOLOG-L] Ecology Colonization Re: [ECOLOG-L] New paper about
"invasive species" debate
All:
3.9 decades ago, I did a different sort of "restoration" project in which
I
"used" "invasive" (I prefer "colonizing") species. In the following ten
years
of observation (could find no ecologists to independently and critically
study and quantify; hence no scientific publication was ever
done) I noticed that as the indigenous species developed, the alien
species
almost entirely disappeared or became a minor element, apparently
dependent
upon disturbance for their persistence. In this particular context, no
"eradication" was done, and in the ensuing 2.1 decades of practice I have
found that eradication efforts often caused more problems than they
solved;
that a healthy indigenous ecosystem could almost always suppress
colonizing
species. Further, it has been my observation that most "invasiveness" is
primarily dependent upon disturbance (e.g., grazing and trampling by
domestic
livestock and other perturbations under which the indigenous flora and
fauna
did not evolve).
Over the period 1972-2000 other projects exhibited similar
characteristics.
WT
----- Original Message -----
From: "Annette Olson" <[email protected]>
To: <[email protected]>
Sent: Monday, July 18, 2011 11:29 AM
Subject: Re: [ECOLOG-L] New paper about "invasive species" debate
Two decades ago, the late Walter Westman wrote thoughtfully on the
subject
of positive and negative effects of invaders. He suggested a phased
strategy
in which eradication of invasive plants would be balanced with
restoration
of native vegetation to minimize both ecological and aesthetic impacts.
Westman, W.E. 1990. Park management of exotic plant species: problems and
issues. Conservation Biology 4 (3): 254-256.
Westman, W.E. 1990. Managing for biodiversity: unresolved science and
policy
questions. BioScience 40 (1): 29.
Annette Olson
Seattle, Washington
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