[APWG] Native "invaders"?

[Wayne Tyson]

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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