Good evening,
First off, thank you for the wealth of responses, a number of them helped
to solidify and clarify ideas on this issue. I had been waiting for all
responses before I replied with a sort of meta-analysis of what came in.
The replies were more numerous and substantial than I had anticipated,
so
thank you again.
Now to clarify. When I mentioned progression, my idea was that an
invasive
species encourages competition, and in some cases extreme and
insurmountable competition. I feel that competition without a doubt is
beneficial, perhaps necessary, for an ecosystem to continue progressing
towards a more complex and stronger state.
The complication arises when an introduced species or a native species
that
becomes dominant are able to outcompete the other species in the
ecosystem
to the point of the only species able to compete is itself. In these
instances, there are various stances to take, some of which I've heard
through responses (again, thank you). From the complete control and
restoration of native (albeit weaker) species, to letting nature run its
course. However, my thought was that ecosystems are cyclical and
self-regulating. And as Wayne Tyson said, we are interrupting and
influencing this. This leads to many more questions. With what I've
learned so far through this posting, exhaustive studies would be needed
to
determine the best course of action for a particular system or species.
Even then, the needed actions to benefit one species might directly
contradict the needs of another. There are multitudes of variables that
need to go into project planning, not the least of which is *us, *and we
cannot foresee the ripple effects of what we'll do.
On the other hand, certain invasive species have led to unforeseen
benefits. I will mention *Tamarix* *spp.* in this instance. But even
with
the detriments and benefits, there is a threshold to each. Likewise,
invasive species seem to provide species-specific detriments (or
benefits).
One can call it a culling of the weak species and the establishment of
stronger (which in my mind is necessary for progression), or unfair
competition, invasive species are not by nature detrimental.
I've rambled far more than I expected to, and not as cohesive as some
might
like. My knowledge and experiences are limited, hence my original
question, but I've a sincere interest in these ideas. Again, I would
welcome any thoughts, ideas, questions, or comments. Thank you all
ECOLOG,
this is a great resource for undergrads, post-docs, and interested
individuals alike. Keep it up.
Have a good night all,
Josh
On Thu, Apr 26, 2012 at 4:44 PM, Wayne Tyson <[email protected]> wrote:
> Ecolog,
>
> I am dismayed that there has been so little response to Huang's
questions.
> Perhaps I am wrong in that assumption and they have been. But it seems
> to
> me that the questions should be addressed and some conclusions
> concluded,
> even if they are two-headed.
>
> I suggest that everyone read the article to which Huang supplied a
> link.
> It is not long, nor is it complicated. I suspect that there may be a
> fundamental flaw in the article's premise, but I will leave that
> judgment
> up to my betters . . .
>
> Coincidentally, Joshua Wilson's original post (Invasion or
> progression?)
> did not define "progression," nor has anyone else, and Wilson has not
> responded to my request for a definition. I think it is essential that
> it
> be defined before his question can be answered. If Josh was just
> joshing
> us, or he is incapacitated, I may have to lower his grade from an A+
> to,
> say, a "C" for mediocrity, due to his unresponsiveness. Are you there,
Josh?
>
> I will await the responses from others on the questions by Huang:
>
> 1. (When) do invasives become native?
>
> 2. Can natives become invasive?
>
> I hope that greater responsiveness will encourage Huang, the chemist,
> to
> continue to take his cross-fertilization attempt seriously and not to
give
> up on ecologists.
>
> WT
>
>
> ----- Original Message ----- From: "ling huang"
> <[email protected]>
> To: <[email protected]>
> Sent: Sunday, April 22, 2012 6:37 PM
> Subject: Re: [ECOLOG-L] Invasion, or progression?
>
>
> Hi
>
> I am a chemist and not an ecologist but I'm very interested in this
thread
> since I enjoy the wetlands area close to Sacramento near the Davis Yolo
> Causeway. I wondered and am interested in this invasive or progression
type
> question. I saw that there was a species called Purple Loosestrife
(Lythrum
> salicaria) that was introduced in the 1800s (?) and is a wetland flower
> that has invaded wetlands. I suppose my question is how far do we go
> back
> to determine if a species is invasive. Is there a time or case when an
> invasive becomes a native? I did see this interesting online article
where
> the question asked was "Can native species become invasive?"
>
> http://ipmsouth.com/2010/11/**23/can-native-species-become-**invasive/<
http://ipmsouth.com/2010/11/23/can-native-species-become-invasive/>
>
> Thanks. Ling
>
> Ling Huang
> Sacramento City College
>
>
> --- On Sun, 4/22/12, Amanda Newsom <[email protected]> wrote:
>
> From: Amanda Newsom <[email protected]>
> Subject: Re: [ECOLOG-L] Invasion, or progression?
> To: [email protected]
> Date: Sunday, April 22, 2012, 3:40 PM
>
> Very intelligent members of the public have asked me this question when
> they approach me in the field and I have some time to chat. It's a
> great
> question, because invasions biology is attacked politically on this
front,
> so it's one to which professionals really must craft a coherent
> response
in
> friendly conversation.
>
> Another point to consider is the evolutionary history of native vs.
> introduced (non-native) species in any particular system. One of the
> reasons non-natives are of concern is that they do not share
> evolutionary
> history with the native community, and this contributes to the
> unpredictable biodiversity loss cited by other comments presented here.
> This can also be discussed in light of the homogenization of life on
> earth, because there are many species favored, facilitated, or directly
> cultivated by humans that are now distributed worldwide. Some of these
> species threaten regional biodiversity (Check out the book Ecological
> Imperialism for a really interesting perspective on colonialism as an
> ecological process via introduction of new dominant species). There's a
> lot coming out now on evolution and invasive species as well that is,
> at
> least in part, reasonably accessible to a general audience or the
academic
> in ecology/evolution who is wanting to step into invasion biology.
>
> Related to this (somewhat tangentially) is that the buildup of
> introduced
> and invasive species in systems like San Francisco Bay has also
> increased
> the number and complexity of biological interactions, both
> introduced-introduced and introduced-native. Increasing professional
> interest in introduced-introduced interactions hasn't yet yielded a
> whole
> lot of generalized hypotheses, but it has opened new windows to how
complex
> this issue is biologically and how best to protect species of interest
> as
> well as local biodiversity.
>
> That was a far longer and more convoluted comment than I originally
> intended! Hopefully, Joshua, some of that is useful perspective. Thanks
> for posing the question to ECOLOG! It can be intimidating to put
something
> like this out there as an undergrad, and I'm glad you took the
initiative.
> It comes up a lot, as you can see, and ECOLOG is a great forum for this
> discussion.
> A.
>
> On Sun, Apr 22, 2012 at 9:19 AM, Ruhl, Nathan <[email protected]>
> wrote:
>
> I posed a very similar question to a group of graduate students and
>> professors during a theoretical ecology seminar a few years ago. The
>> central premise was that humans, by virtue of our
>> innate-desire/ability
to
>> alter our surroundings, have caused a general decline in biodiversity
>> globally. That is,humans are the primary vector for a loss of global
>> biodiversity, not the "non-native"/"invasive" species. The question
>> was,
>> is reduction of biodiversity bad or is it simply evolution in favor of
>> species better adapted to live in a human-altered landscape?
>>
>> After much debate, the consensus was more or less that we don't know
what
>> all the ecological implications of a rapid global reduction in
>> biodiversity
>> will be and, because we have only one habitable planet currently, it
would
>> be a good idea not to break it. Therefore, in the absence of a
>> rigorous
>> ecological understanding that we may never actually achieve, humans
should
>> be taking steps to promote the conservation of biodiversity whenever
>> possible.
>>
>> N Ruhl
>> Ohio University
>> ______________________________**__________
>>
>> On Sun, Apr 22, 2012 at 10:01 AM, Joshua Wilson
>> <[email protected]>**wrote:
>>
>> > Good morning,
>> >
>> > I know that invasive and non-native species have been getting a
>> > great
>> deal
>> > of attention lately, and justly. I understand the basic ecological
>> impacts
>> > and concerns invasive species cause, and the disruption of the
>> > native
>> > system. My main question is:
>> >
>> > Why are invasive species considered a nuisance, instead of
>> > adaptation,
>> > progression, or perhaps ecosystem evolution?
>> >
>> > Yes, human beings have been a main cause of the large majority of
these
>> > invasions. But even so, I feel we are part of the natural system. If
an
>> > invasive species exhibits more plasticity or is more competitive and
>> > adaptive than the present species in an ecosystem, does that
necessarily
>> > imply catastrophic impacts? There are multiple arguments against
this, I
>> > know, many of them strong and verified. I am not an advocate of
invasive
>> > species dominated ecosystems, but am just curious why this change
>> > and
>> shift
>> > is considered so extremely detrimental. I feel that stable and
>> progressive
>> > change and adaptation is the basis of a strong ecological system.
>> >
>> > I would welcome any thoughts on this, or perhaps to start a
discussion.
>> I
>> > am still an undergrad, so my question may seem farfetched and
ridiculous
>> to
>> > some. Even so, just something to ponder on a lovely Sunday morning.
>> >
>> > Have a good day all,
>> >
>> > Josh Wilson
>> >
>>
>>
>>
>> --
>> Gary D. Grossman, PhD
>>
>> Professor of Animal Ecology
>> Warnell School of Forestry & Natural Resources
>> University of Georgia
>> Athens, GA, USA 30602
>>
>> http://grossman.myweb.uga.edu/
>> <http://www.arches.uga.edu/%**7Egrossman
<http://www.arches.uga.edu/%7Egrossman>
>> >
>>
>> Board of Editors - Animal Biodiversity and Conservation
>> Editorial Board - Freshwater Biology
>> Editorial Board - Ecology Freshwater Fish
>>
>>
>
>
> --
> Amanda Newsom
> Graduate Student
> Bodega Marine Laboratory
>
> ``Life shrinks or expands according to one's courage'' -- Anais Nin
>
>
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