[APWG] Invaders

[Matt Heard]

Dear All,

I don't want to open up a can of worms here, but I think that there are
still some important points to make about this NY Times article.

First off, while I can't speak for the authors, I'd argue that the reason
that they wrote the article in the first place was to discuss the concept of
ecological saturation.  By pointing out that plants can be continually added
without extinctions occurring, Sax and Gaines point out that our traditional
perspective, in which we view communities as groups of tightly co-evolved
organisms that exist at some optimal level of diversity, may not be correct.
 What may be most important to what makes it in a community is what can
disperse there (via humans or not).  That is why in the original PNAS
article they compare plants to birds, which tend to show a different trend.
 On islands where birds are introduced, we tend to see equivalent declines
in native richness.

So what's important to take from this...Well I'd say that 2 things are
important.  First off, you have to take what newspapers report with a grain
of salt.  In this case, they went with the flashy finding that we don't see
that many extinctions occurring in plants when in reality we see different
trends in other groups.  And second, I think that we need to understand that
there is a difference between exotics and invasives.  When they state that
there are approximately 2000 exotic plants in NZ, not all of them are
invasive and wreaking havoc.  We have to be careful to call all change bad,
when many of these species aren't causing any problems.  While I know
everyone doesn't agree with me on this, I think this is an important point
to make because characterizing all exotics as problematic can lead to
overspending of conservation/management budgets, which are often low and
crucial for dealing with actual problems.

Feel free to bash any of this as you all see fit.

Matt
-- 
********************************************************
Matt Heard
PhD Student
Brown University
Ecology and Evolutionary Biology
80 Waterman St. Box G-W
Providence, RI 02912
heard.m at gmail.com
heard.m.googlepages.com
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