<html dir="ltr"><head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style></style>
<meta name="GENERATOR" content="MSHTML 8.00.6001.18928">
<style title="owaParaStyle"><!--P {
MARGIN-TOP: 0px; MARGIN-BOTTOM: 0px
}
--></style>
</head>
<body bgcolor="#ffffff" ocsi="x">
<div dir="ltr"><font color="#000000" size="2" face="Tahoma">These definitions make perfect sense to me, simple but to the point.
</font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div style="DIRECTION: ltr" id="divRpF836962">
<hr tabindex="-1">
<font size="2" face="Tahoma"><b>From:</b> apwg-bounces@lists.plantconservation.org [apwg-bounces@lists.plantconservation.org] On Behalf Of Wayne Tyson [landrest@cox.net]<br>
<b>Sent:</b> Friday, July 30, 2010 5:35 PM<br>
<b>To:</b> apwg@lists.plantconservation.org<br>
<b>Subject:</b> [APWG] Plants Alien Definition<br>
</font><br>
</div>
<div></div>
<div>
<div><font size="2" face="Arial">APWG: </font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Definitions, to be useful in moving a discussion forward as opposed to spinning its wheels in polarizing dialectics, must be understood equally well and agreed upon by all participants. While it would seem unnecessary to engage
in such a discussion with respect to "alien" and "invasive," I find that different posts seem to define these key terms differently. Therefore, I will propose some definitions (particularly as they relate to plants, but they should hold true for any organism).
I ask that responses be confined to corrections to the definitions in the form of alternative definitions to keep the discussion from wandering off into the intellectual weeds. Separate footnote discussions about the reasoning that supports the definitions
will be welcome, of course, but I respectfully request that we keep it simple and stick to the subject. It is not my intention to preserve these definitions, nor to start arguments; my hope is that definitions will evolve that will serve to communicate these
concepts clearly. If no unanimity can be found or resolved, clarity in communication can still be served by using modifiers to define the kind of "alien" or "invasive" is intended. Anyone can define anything any way one wants, but only one person may understand
that definition in the same way as the originator. </font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">1. <em>Alien</em> (plant or other organism). An organism that did not evolve with other organisms in a given habitat.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">2. <em>Invasive</em> (plant or other organism). An organism that exploits niches that meet its requirements for life.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">Relevant comments:</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">1. All plants and animals reconcile their requirements for life with environments that meet them. Invasions may occur, but the invading organisms must "find" or create environments that are suitable for their requirements in
order to establish and maintain populations that are able to reproduce. </font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">2. Environmental change is the rule, and there are no exceptions. Change may be very fast or very slow, but nothing stays the same.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">3. Organisms "track" changes within their sphere of influence/capacity.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">4. Analogously, human cultures acquire places to live in which they exclude others (aliens). In that process, other species exploit the effects of human cultural differences. Some species of rats, for example, have become almost
entirely dependent upon human cultures for their existence and would be restricted to non-cultivated or undeveloped habitats and might not survive, at least in large populations, outside the boundaries of human cultures. Certain plants have become highly dependent
upon human cultures for their existence ("crops" and "weeds"), and may have evolved as a result, perhaps to such an extent that they could not otherwise exist (or could be highly restricted to certain habitats) in its absence.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">I look forward to alternative definitions and supportive reasoning and discussion.
</font></div>
<div><font size="2" face="Arial"></font> </div>
<div><font size="2" face="Arial">WT</font></div>
</div>
</body>
</html>