How about if we consider that invaders have become native when all efforts to eradicate them are futile?
Martin M. Meiss 2012/4/26 David Duffy <ddu...@hawaii.edu> > "I feel that competition without a doubt is beneficial, perhaps necessary, > for an ecosystem to continue progressing towards a more complex and > stronger state." > > "However, my thought was that ecosystems are cyclical and self-regulating." > > "native (albeit weaker) species" > > I am not sure there is much evidence that ecosystems progress towards a > "more complex and stronger state", even if we do not ask whether if > competition is "beneficial" or even a dominant force. Nor is there > evidence, with a few exceptions, that ecosystems are cyclical, much less > self regulating and then only if you carefully pick your scale. One might > argue that much of ecological theory has been a repeat of the > Gleason-Clements debate, an argument between those who seem life dominated > by random events and those who see homeostasis and orthogenesis, perhaps > with a pinch of Nietzchian "der Wille zur Macht" thrown in. This colors > current discussions of invasive species, probably far more than any > confusion over what "invasive" means. > > David Duffy > > > On Thu, Apr 26, 2012 at 3:11 PM, Joshua Wilson > <joshua.m.wils...@gmail.com>wrote: > > > 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 > > > > > > > > > -- > > Pacific Cooperative Studies Unit > Botany > University of Hawaii > 3190 Maile Way > Honolulu Hawaii 96822 USA > 1-808-956-8218 >
