[APWG] ecological services of weeds?

[Wayne Tyson]

Dear Megan:

The "ecological services of weeds" issue comes up now and then, and it commonly begins and ends with confusion, or worse, presumptions about "facts" that lead to "conclusions" that are rarely, if ever, the whole story. So it is a challenge to answer your question responsibly. 

One can cherry-pick cases like one you cite with respect to many "weed" species and come up with "answers" that spotlight a "fact" that is as impressive as it is misleading. 

"Ecology" is about the whole story, not just part of it, so the fact that the Southwest willow flycatcher, for example, "uses" tamarisk, does not necessarily mean that the bird is better off as a result of the tamarisk than it was before its original habitat was displaced by the tamarisk. If, say, a group of humans lost their homes, they would gravitate to the best alternative they could find, even if it was nothing but a bunch of drain pipes or improvised lean-to shelters. 

So the flycatchers may appear to be receiving "ecological services" from tamarisk to us, but the "ecological question" is not whether they have adapted to an altered habitat, but what that means in comparison to the alternative of the habitat under which it evolved and prospered. And it says nothing about how countless other species have been affected by the change. 

Some indigenous species have "prospered" because of shifts toward alien "weeds." The mourning dove, for example, has "enjoyed" a population explosion because of alien plant introductions, including "crops" and "weeds." But this says nothing about  the tradeoffs, the sacrifices that other species have had to make to produce the population boom in dove populations. 

While "weeds" do perform "ecological" functions as a matter of "fact," whether or not one can truthfully term them "services" may be another matter. 

WT

PS: I would be interesting to know where you're going with this. 
  ----- Original Message ----- 
  From: Bowes, Megan 
  To: 'APWG at lists.plantconservation.org' 
  Sent: Monday, April 26, 2010 2:14 PM
  Subject: [APWG] ecological services of weeds?


  I'd like to inquire if anyone out there has experience with the "ecological services of weeds".  The Southwest willow flycatcher and tamarisk is a classic example.  We'd like to hear from researchers and land managers alike, and would especially like any information about examples with other taxonomic groups (herps, mammals, etc.).  Thanks for any help with this.

   

  Megan Bowes

  City of Boulder

  Open Space and Mountain Parks Department

  66 South Cherryvale Road,  Boulder, Colorado  80303

  720.564.2084 (voice) 720.564.2072 (fax)

  bowesm at bouldercolorado.gov

   



------------------------------------------------------------------------------



  _______________________________________________
  PCA's Alien Plant Working Group mailing list
  APWG at lists.plantconservation.org
  http://lists.plantconservation.org/mailman/listinfo/apwg_lists.plantconservation.org

  Disclaimer
  Any requests, advice or opinions posted to this list reflect ONLY the opinion of the individual posting the message.


------------------------------------------------------------------------------



  No virus found in this incoming message.
  Checked by AVG - www.avg.com 
  Version: 8.5.437 / Virus Database: 271.1.1/2836 - Release Date: 04/26/10 06:31:00
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.plantconservation.org/pipermail/apwg_lists.plantconservation.org/attachments/20100427/87f8a6d3/attachment.html>