Greetings~
I am working on a predictive model at the Chicago Botanic Garden and am often
trying to decode the way we communicate about this topic. At least three
different paradigms address non-native and non-native invasive plants. As a
general assessment, I have seen, "weedy", a horticultural and/or agricultural
term (IMO), superimposed on "invasive", a ecological term (IMO) and "noxious",
a legal term (in Illinois, anyway) used synonymously, as well.
While I see that invasive can be a subjective term, as scientists, we can
define the term (as this is fast becoming the standard in publications) to
minimize much subjectivitity, and indeed, we have a plethora of literature that
attempts to do this. Some address not only the "invasive" term, but all terms
involved in invasion ecology as well as the process itself. Among others, I
find this 1999 attempt to be one of the most specific.
Based loosely on Parker, IM, D. Simberloff, WM Lonsdale, K. Goodell, M.
Wonham, PM Kareiva, MH Willilamson, B. Von Holle, PB Moyle, JE Byers & L.
Goldwasser. 1999. “Impact: toward a framework for understanding ecological
effects of invaders”. Biological Invasions 1: 3-19.
Invasive Species a species, usually non-native, that has a quantitative and
statistically significant direct or indirect adverse biological impact on
native flora or fauna or abiotic input where impact is based on total area
occupied, abundance and some measure of the impact per individual species
and/or abiotic unit.
Further, Richardson, Pysek, Rejmanek, Barbour, Panetta and West (2000) say
"invasion further requires that introduced plants produce reproductive
offspring in areas distant from sites of introduction (appx scales: > 100m over
< 50 years for taxa spreading by seeds and other propagules; > 6m/3 years for
taxa spreading by roots, rhizomes, stolons or creeping stems)."
And the IUCN definition for "Alien Invasive species" "means an alien species
which becomes established in natural or semi-natural ecosystems or habitat, is
an agent of change, and threatens native biological diversity." (Feb. 2002).
The never-ending discussion....
As a side note, regarding the Daehler and Thompson and Davis papers noted by
Teresa; Rejmanek, M., Richardson, DM, Barbour, MG, Crawley, MJ, Hrusa, GF,
Moyle, PB, Randall, JM, Simberloff, D., and Willilamson, M. in the April 2002
Bulletin of the Ecological Society of America say of the Thompson and Davis
paper, "We believe that the definition of invasive by Davis and Thompson (2001)
would be more hindrance than help to conservation." The commentary by the
above authors is entitled "Biological Invasions: Politics and the Discontinuity
of Ecological Terminology".
KEK
Teresa Woods <[EMAIL PROTECTED]> wrote:
A couple more relevant references on the definition theme:
Daehler, C.C. 2000. Two ways to be an invader, but one is more
suitable for ecology. Bulletin of the Ecological Society of America
82:1101-102.
Davis, M.A. & K. Thompson. 2000. Eight ways to be a colonizer; two
ways to be an invader: a proposed nomenclature scheme for invasive
ecology. Bulletin of the Ecological Society of America 81:226-230.
Teresa
Teresa Woods
Graduate Assistant
Division of Biology
232 Ackert Hall
Kansas State University
Manhattan, KS 66506
785-532-9834
[EMAIL PROTECTED]
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