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

Mon Mar 5 18:04:16 CST 2012

Regarding Robert's insightful question about "how" vs. "why" of species invasion, let me briefly address the exotic Phragmites australis invasion going on in the Great Salt Lake marshes and apparently everywhere else.  And this may be relevant to catastrophic forest blow-downs or fires being discussed.  Twentyfive years ago, due to a freakish two years of super-normal precipitation the Great Salt Lake rose to historic high flood levels, inundating and "destroying" most of the surrounding fresh water marshlands (mostly diked waterfowl refuges such as the famous Bear River National Wildlife Refuge).  In the intervening years the water levels gradually dropped, exposing much of the shoreline muds for air-borne Phragmites germination and colonization.  Where the exotic genotype came and how it got here is still not known.  But now, monotypic circular clones often a hundred feet in diameter dot the marshlands where the native cattails and bullrushes once provided wildlife habitat.  This is what scares the be-geebers out of the "sportsmen" and justifies helicopter application of RoundUp.  However like in Robert's forest story, the native marshland species rapidly reestablish themselves, but a few unkilled rhizomes of the bad actors are still there lurking.  I really don't know whether to be hopeful or not. Regards,  Ty Harrison

----- Original Message ----- 
  From: Robert Layton Beyfuss 
  Cc: apwg at lists.plantconservation.org 
  Sent: Monday, March 05, 2012 2:38 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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