Dear Ling, WT, and Ecolog, I think the term invasive implies that whatever is now dominating a system came from some ambiguously demarcated "outside" due to human intervention. The term is largely framed by our conception of history, and so we are inconsistent about where we draw this line for outside. From my experience, most biologists use the term invasive in reference to a dominant organism which is from outside an area it could not have dispersed into without human assistance. For example, most do not consider species to be invasive when disturbance regimes or other processes have been altered by humans from past conditions (this "past" can be equally ambiguous in discussions) and allow for their dominance of local areas where they could have dispersed into but probably didn't occur. I believe it is for this reason I have never heard a biologist say a raccoon is invasive in North America abefore this discussion. There may be examples which contradict this definition that I have been using though, and I would appreciate the correction and also would very much so appreciate if anyone has a citation for a better definition in use if I am off on this.
So, to get around to addressing Ling and WT's questions, if we are consistent with the underlying ideas of what is outside and what is inside are used in our definition, native implies "inside" and invasive implies "outside", both to some predetermined space, and so I would say that the answers to Ling's questions are: 1. (when) can an invasive become native? no (or, never) 2. can an invasive become native? no. I think the words are actually logically exclusive of the other no matter where we draw the line, it is where we draw that line that is contentious, and essentially we would have to switch our conception (whatever that may be) for an invasive to become native. Best, Ryan Unks On Sat, Apr 28, 2012 at 11:44 AM, Eric North <xcs...@hotmail.com> wrote: > I cant help but find irony in that in one breath (read: keystroke) we > cannot agree on a definition of an "invasive species" "invasion" or the > like, or, seemingly, even if there is such a thing as invasive species when > put into the context of evolutionary time. At the same time, there is the > opinion at least being discussed here, that there are species that are so > successful as to be "eradicable". > > eric > > Eric North > All Things Wild Consulting > P.O. Box 254 > Cable, WI 54821 > 928.607.3098 > > > > > Date: Fri, 27 Apr 2012 22:03:25 -0700 > > From: landr...@cox.net > > Subject: Re: [ECOLOG-L] Plants Invasive natives? Re: [ECOLOG-L] > Invasion, or progression? > > To: ECOLOG-L@LISTSERV.UMD.EDU > > > > Ecolog and Joshua: > > > > Being cocksure about anything is a bad habit for anybody to cultivate, is > > damnfoolish for ecologists, and verboten for scientists. Egocentrism and > > science do not mix, but lo, the plethora of contradictions of this > statement > > that exist in the really, really unreal world of civilization. Had we > been > > possessed of better angels, we might have rejected the mess of culture > > (cultivation--enslavement of plants and animals) at the outset and would > > still be residing in Eden, laughing and loving and standing in awe of > this > > awesome Earth and Universe, calling our place in it, and seeing it as, > good. > > > > We might be extinct. Maybe we are, in ecological terms. For the most > part we > > have become wholly dependent upon the products of culture--and these > pixels > > are proof of that, at least in this instance? Irony anyone? > > > > With respect to plants (more irony, at least in ambiguity), I am > astonished, > > nay, blown away, that the concept of "natives" "invading" a place where > they > > evolved, exists at all. I must be missing something, but I'll be damned > if I > > can guess what it is. > > > > WT > > > > > > ----- Original Message ----- > > From: "Joshua Wilson" <joshua.m.wils...@gmail.com> > > To: <ECOLOG-L@LISTSERV.UMD.EDU> > > Sent: Thursday, April 26, 2012 6:11 PM > > Subject: Re: [ECOLOG-L] Plants Invasive natives? Re: [ECOLOG-L] > Invasion, or > > progression? > > > > > > > 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 <landr...@cox.net> 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" < > ling.hu...@prodigy.net> > > >> To: <ECOLOG-L@LISTSERV.UMD.EDU> > > >> 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 <ajnew...@ucdavis.edu> wrote: > > >> > > >> From: Amanda Newsom <ajnew...@ucdavis.edu> > > >> Subject: Re: [ECOLOG-L] Invasion, or progression? > > >> To: ECOLOG-L@LISTSERV.UMD.EDU > > >> 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 <nr343...@ohio.edu> > 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 > > >>> <joshua.m.wils...@gmail.com>**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 > > >> > > >> > > >> ----- > > >> No virus found in this message. > > >> Checked by AVG - www.avg.com > > >> Version: 10.0.1424 / Virus Database: 2411/4952 - Release Date: > 04/22/12 > > >> > > > > > > > > > ----- > > > No virus found in this message. > > > Checked by AVG - www.avg.com > > > Version: 10.0.1424 / Virus Database: 2411/4960 - Release Date: 04/26/12 > > > > >
