[APWG] Ecosystems Invasions Re: Do ecosystems resistinvasion?Invasion and cropping Re: rate of change

[Wayne Tyson]

LRB and y'all:

Thanks for this anecdote. I'm actually a big fan of anecdotes, but it has been said that they are "the singular of data." I have "walked" areas and felt that I "knew" what was and was not there. Then I have surveyed the same area with various techniques (point-intercept, transect, quadrat, etc.) and found that I really had no real concept of what was and wasn't there. Of course, absence is more difficult to determine than presence ("Absence of evidence is not evidence of absence." --Author unknown)

Cases do not necessarily explain principles; even if there are data, such is not necessarily the case. 

It is not necessarily surprising that a disturbed area is not invaded, and even six years may be insufficient to provide evidence of the absence of any particular species. 

Nonetheless, this might be a case worthy of closer attention. The lack of regeneration of the desired timber species would certainly warrant study. 

The fact that Cornell would be involved in this sort of thing is at first surprising, then maybe not. What so many farmers, tree-farmers (foresters?) fail to understand is the role of ecosystem dynamics and the benefits of other species. An unfortunate number (majority?) of managers continue to entertain a number of myths like "removing competition." It ain't necessarily so . . .

I will insert comments and questions in [[double-brackets thus. WT]]

Certainly, "disturbance" ALONE is not necessarily the SOLE causal factor in cases of invasion--the variables are infinite (at least comparatively speaking). "God" is in the context, and the devil is in the details. 

WT

----- Original Message ----- 
  From: Robert Layton Beyfuss 
  Cc: apwg at lists.plantconservation.org 
  Sent: Monday, March 05, 2012 1:38 PM
  Subject: Re: [APWG] Ecosystems Invasions Re: Do ecosystems resistinvasion?Invasion and cropping Re: rate of change


  I don't think Utah is any more kooky than any other state in this regard. An interesting twist on this same topic is that sometimes even highly disturbed sites seem to resist invasion. A friend of mine at Cornell  is charged with managing a large area of forest (4,000 acres) for timber production, first and foremost.  He hires a tractor driven mist blower to spray herbicide on 50 acre blocks within the forest to suppress understory vegetation, primarily beech tree root sprouts which can and have made it impossible to even walk through some places in the forest.   I was seriously angry at him when he killed off a small population of American ginseng as a result of this "collateral" damage. What made me even more upset however, was my assumption that these 50 acre blocks would quickly be invaded and overrun by the many species of known invasive plants that were already present in adjacent blocks and all along the access roads and trails. These weeds included Japanese barberry, non native honeysuckles, garlic mustard, autumn olive, multiflora rose and a few others.  Last summer he invited me to tour some other blocks within this forest that he had sprayed 2, 4 and 6 years ago. I expected the worst but to my surprise, I really could not tell at a glance which blocks were sprayed 6 years ago versus some that were not sprayed at all. Somehow, certain herbaceous perennials such as Christmas fern and others had returned and there were no more invasive plants present then before the spraying. I still do not understand why. Ironically though, the spraying did not necessarily achieve the result of increasing the presence of the desired timber species from the existing seed bank on the forest floor, or even increasing the growth rate of the overstory trees. Sometimes, as Cubby from WV noted in a previous post regarding stilt grass, it is possible to find out "how" an invasive species gets into an area but it is much, much more daunting to try to explain "Why". Disturbance alone does not seem to fit the bill in all cases. 

   

  From: Ty Harrison [mailto:tyju at xmission.com] 
  Sent: Monday, March 05, 2012 2:49 PM
  To: Wayne Tyson; Robert Layton Beyfuss; Ryan McEwan; John
  Cc: apwg at lists.plantconservation.org
  Subject: Re: [APWG] Ecosystems Invasions Re: Do ecosystems resistinvasion?Invasion and cropping Re: rate of change

   

  APWG:  Regarding Wayne Tyson's astonishment (below),.  

    Wayne et al:  Little do you know! (about the magnitude of helicopter applied herbicide here in Utah).  Read this and weep:  http://www.sltrib.com/news/ci_15185646 .  Massive amounts of glyphosate are being dumped annually on the non-native genotype of Phragmites australis in the public and private marshlands around Great Salt Lake:  http://www.utahwildlifephotos.com/keyword/phragmites/1/470783372_dUyTS#!i=470783372&k=dUyTS

    I know everyone thinks Utah is kooky, but this is an accepted practice, dare I say "best management practice" BMP!!!

    Ty Harrison

     

     

     

     

       



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