Some non-indigenous species don't cause problems in their new environment - but they are not called "invasive." This term is for those that "cause trouble" one way or another. A couple of months ago we were snorkeling in the Turks and Caicos islands, which are less developed than many other places, so we thought the reefs etc. would be in reasonable shape. We saw more lionfish than any other kind of fish. They seem to have eaten up everything else, since the native species don't recognize them as predators. Depressing...
> 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 >
