Re lionfish: Actually that's what I had in mind when I said "eating everything in sight." They have been well documented to reduce populations of reef fish, due to predation on juveniles. There are plenty of peer reviewed papers to this effect, even demonstrating phase shifts of coral to algae-dominated systems, due to lionfish eating herbivores.
One example: Mark Albins documented the recruitment of newly settled reef fishes on 20 patch reefs: 10 reefs with lionfish and 10 reefs without. Fish censuses were conducted at one week intervals for five weeks. Recruitment was significantly lower on lionfish reefs than on control reefs at the end of the experiment. On one occasion, a lionfish was observed consuming 20 small wrasses during a 30 minute period. It was not unusual to observe lionfish consuming prey up to 2/3 of its own length. Results of the experiment show that lionfish significantly reduce the net recruitment of coral reef fishes by an estimated 80%. The huge reduction in recruitment is due to predation. > Interesting points. > > At the same time alien/introduced/invasivespecies that truly alter an > environment, out compete others, and in general, lead to ecological mayhem > - I am not aware of any examples outside of, maybe, humans. > > There exists serious economics benefits to many in the realm of 'alien > species battles'. The lionfish, Pterois volitans and, possibly, P. miles, > are a good example. Even quasi-scientific articles continue to villify > them, describing their voracious appetites and ability to out-compete all > native species. Yet stomach anlysis fails to support those contentions. > There is no question that it has successfully established itself, do date > from New Hampshire to Colombia, throughout the Caribbean and it would be a > miracle if it is eradicated. But significant ecological perturbation has > yet to be proven. That does not stop dive shops, REEF, and a plethora of > other organizations from putting together derbies, round-ups, and the like > geared to the illusion that this is the way to eradicate the pest. It > should be noted that all that organize such events charge for it, thus > deriving a benefit from the lionfish. In areas where scuba diving was > waning, > the arrival of the lionfish has been a boost. > > Thus, despite the generally accepted view that eradication is near > impossible, it is turned into a cash cow - cash fish. > > Indeed a fresh assessment of this issue should be welcome as if it is > accepted that the 'Earth' is changing, why is it blieved the biota of the > various localities will remain unchanged. International trade, > globailzation, and like activities are conducive to such introductions and > it would be through such new thinking that the issue would receive a fresh > understanding. > > Esat Atikkan > > > > > --- On Fri, 6/10/11, Judith S. Weis <jw...@andromeda.rutgers.edu> wrote: > > > From: Judith S. Weis <jw...@andromeda.rutgers.edu> > Subject: Re: [ECOLOG-L] EcoTone: Speaking of species and their origins > To: Date: Friday, June 10, 2011, 2:30 PM > > > IMHO, they are attacking a "straw man." I haven't seen many scientists, > managers, policy-makers etc. getting all worked up about non-indigenous > species who integrate well into the environment, get a green card, pay > their taxes etc. The ones that are being attacked and for which they are > spending lots of money are the truly invasive ones that cause ecological > and economic damage - eating up everything in sight, outcompeting native > species for food, space etc. - and generally taking over - affecting the > environment in negative ways. > > > > >> An essay published in the June 8 issue of Nature is causing something of >> a >> stir. Eighteen ecologists who signed the essay, titled "Don't judge >> species on their origins," "argue that conservationists should assess >> organisms based on their impact on the local environment, rather than >> simply whether they're native," as described in a recent Scientific >> American podcast. >> >> In the essay, Mark Davis from Macalester College, St. Paul, Minnesota >> and >> colleagues argue that adherence to the idea of non-natives as "the >> enemy" >> is more a reflection of "prejudice rather than solid science," wrote >> Brandon Keim in a Wired Science article. As the authors wrote, the >> "preoccupation with the native-alien dichotomy" among scientists, land >> managers and policy-makers is prohibitive to dynamic and pragmatic >> conservation and species management in a 21st century planet that is >> forever altered by climate change, land-use changes and other >> anthropogenic influences. As a result of this misguided preoccupation, >> claim the authors, time and resources are unnecessarily spent attempting >> to eradicate introduced species that actually turn out to be a boon to >> the >> environment; the authors cite the non-native tamarisk tree in the >> western >> U.S. as an example of this... >> >> Read more and comment at >> http://www.esa.org/esablog/ecologist-2/speaking-of-species-and-their-origins/ >> >
