Well, several responses have answered in the affirmative so far as natives becoming invasive, with examples. Raccoons and Eastern Red Cedar come to mind as examples mentioned so far. I won't comment further here on my thoughts about them. So far as "When do invasives become native?": What about when people who never knew them as exotics are the oldest people looking. That would make Russian Thistle and both species of Tamarisk now native in the western U.S. But, there are control programs for Tamarisk. So far as I know, only farmers and ranchers make any effort to control Russian thistle (tumbleweed).
Another example of exotic to native so far as function is concerned might be common carp in North America. Which brings to mind that a fair number of exotic fishes have been planted in locales where they have become an accepted (and even welcomed) part of the local fish fauna. Some of them are "sports fishes." Among these are several trouts from North America transplanted to other parts of North America, Europe, Africa, S. America; Several centrarchids from eastern North America transplanted to western North America, Africa, S. America; Brown trout from Europe to North America; striped bass from the Atlantic seaboard of North America to interior river systems in North America. If the introduction is on purpose for a supposed benefit, does it still count as invasive when it becomes widely established? David McNeely ---- 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/ > > 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> > > > > 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 -- David McNeely
