[APWG] Native "invaders"?

[Ryan McEwan]

Hi all,

I think Wayne has made a bunch of interesting points, but I also think
he is exaggerating, or pressing the point to far.  "Invasive"  does
have some biological meaning, as does "Exotic".  I encourage anyone to
go back to the original book by Charles Elton. You can get a used copy
inexpensively.  Cases are very clear of species expanding rapidly
through native ecosystems reeking havoc along the way.  Pressing into,
and through, ecosystems that were not radically altered by humans.
Some of these species CLEARLY have a negative effect on biodiversty
and/or radically alter ecosystem function.  Some of these species are
unambiguous in expressing ecological activity that just was not seen
in native species.  They dont play by "the rules."

So it is a matter of whether we care or not.  Let the landscape become
an Amur honeysuckle shrubland, with consequent crashing of floral
biodiversity, or not.  If you want to argue that on an "evolutionary
time scale" invasive species are not real..that over the great sweep
of geological time that invasive species are not even a tiny
hiccup....fine, I wont quibble.  But, to me, that is a senseless place
from which to make decisions about taking action.  The same thing
applies to, for instance, climate change, and in fact, to things like
cancer in humans.  Should humans let those things run their course as
well?

To me, Wayne, and sometimes others, get so wound up in pointing out
marginal cases where, truely, cultural issues are present, and
language seems ambiguous, that they press beyond common sense.  Of
course, organisms will do "what they can, when they can" etc, but this
is completely unhelpful for natural areas management or advancing
science.

Ryan



On Mon, Sep 17, 2012 at 2:06 PM, Wayne Tyson <landrest at cox.net> wrote:
> ALL organisms are "opportunistic." When the requirements for an organisms
> are met, it will flourish; when not, not. "Weeds" and "invasives" are
> CULTURAL terms, not ones which fully define what is really going on.
>
> Life is a squishy, complex process, a confusion of feedback loops in a
> constant "state" of flux. Language always will be inadequate; the challenge
> is to make it reflect reality more than be misleading.
>
> WT
>
> ----- Original Message ----- From: "Addsum-Tony Frates"
> <afrates at addsuminc.com>
> To: "Wayne Tyson" <landrest at cox.net>
> Cc: "John" <jmbarr at academicplanet.com>; <apwg at lists.plantconservation.org>
> Sent: Monday, September 17, 2012 9:37 AM
> Subject: Re: [APWG] Native "invaders"?
>
>
>
>
>
> Regardless of the question of adaptation vs. invasion, the question posed
> is:
>
>
> "Is there a word available to us to describe a biological entity's
> positive response to human-induced disturbance?"
>
>
> A good article to help to frame the topic in general is:
>
> http://www.ias.ac.in/jbiosci/dec2004/461.pdf
>
> The term "opportuntistic" has been offered although it seems to me to
> be generally inadequate (although somewhat helpful).
>
> We then end up chasing our tails when, for example, native  plants
> that are "opportunistic" either in response to disturbances (of all
> kinds) in their natural range, or because they are "out of place"
> (also for various reasons but almost always due to us) are then
> sometimes referred to as "weedy" which then creates all sorts of
> confusion.
>
> So we have to carefully separate the causes of the apparent
> "explosion" of organisms both based on the type of disturbance and
> also by whether it is growing outside of the ecosystem from which is
> naturally evolved - and probably other factors too.
>
>
> Tony Frates
>
>
>
>
>
>
>
> Quoting Wayne Tyson <landrest at cox.net>:
>
>> John,
>>
>> It's adaptation, not "invasion." When the context changes, by human
>> agency or anything else, populations shift accordingly. Organisms and
>> their environment are in a continuous process of change. Doves and
>> rodents, for example, respond to increases in things like food supply
>> (of course, it's more complex than that, but food and water are the big
>> variables that affect most organisms.
>>
>> I have concocted a "Law" of biology: "Organisms do what they can, when
>> they can, where they can."
>>
>> Discuss?
>>
>> WT
>>
>>
>>
>> ----- Original Message ----- From: "John"
>> To: "john
>> Sent: Saturday, September 15, 2012 2:14 PM
>> Subject: [APWG] Native "invaders"?
>>
>>
>>> Is there a word or phrase for those species that might be native,   but
>>> because of their adaptability to humans and human actions,   might be
>>> considered invasive species?
>>>
>>> I am not interested in rehashing the definition of invasive   species,
>>> these are all native pre-human history.  The negative   impact on humans or
>>> the environment is lacking in some cases and   clear in others.  I am
>>> looking for another word or phrase to   indicate those species whose
>>> population growth is directly tied to   human action.
>>>
>>> I know that, in general, armadillo are not considered invasive   species
>>> because they invaded under their own power without an   assist by humans.
>>>
>>> In the Austin area, I can think of several bird species that were native
>>> to the area, but whose populations have exploded because of human's impacts
>>> on the environment.
>>>
>>> They are:
>>> White Winged Doves
>>> Boat-tailed Grackles
>>> Cliff swallows
>>> Blue Jays
>>> Purple Martins (I hesitate to include this popular bird, however......)
>>> Brown headed cowbirds
>>>
>>> The White Winged Doves used to be rare to endangered, then they learned
>>> to nest outside of South Texas thorny scrub and to visit backyard bird
>>> feeders.  They have moved steadily north from south Texas to Dallas over the
>>> past 20 years displacing other dove species.
>>> Boat-tailed Grackles love to congregate in urban areas at night and
>>> forage in the surrounding suburban and rural areas during the day looking
>>> for bugs and grubs stirred up by tractors and lawnmowers.
>>> Cliff Swallows have expanded their range and numbers by using   highway
>>> underpasses.
>>> Blue Jays are one of the most problematic.  They follow the encroachment
>>> of suburban sprawl especially backyard bird feeders,   then eliminate or
>>> displace the less aggressive Scrub Jays.  Blue   Jays are nest robbers, and
>>> one of the predators on our endangered   Golden Cheeked Warbler and Black
>>> Capped Vireos.
>>> Purple Martins nest almost exclusively in human built houses.
>>> Brown headed cow birds have become year round residents because   their
>>> natural affiliation with migratory Bison has been replaced by  perennial
>>> cattle herds in fenced pastures.
>>>
>>> Any thoughts?
>>>
>>> john in Austin
>>>
>>>
>>>
>>>
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>>
>>
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