[APWG] Native "invaders"?

Addsum-Tony Frates afrates at addsuminc.com
Mon Sep 17 11:37:17 CDT 2012



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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