the question is especially important in small isolated territories. For some islands with impulse-unstable ecosystems invasive species can be the only (!) mechanism of supporting the necessary level of biodiversity. I even published some article with colleagues belonging to Anak Krakatau island in the Sunda Strait. Between invasive species there can be even from Red Book of the area So, in some cases invasion impacts are positive.
Anyway I agree that assessments of long term invasions are the most complicated and consequences (direct or indirect) can appear after years of inactive stage.
I recommend Chapter 19 Socio-Economic Impact and Assessment of Biological Invasions19 Socio-Economic Impact and Assessment of Biological Invasions (by Rosa Binimelis, Wanda Born, Iliana Monterroso, and Beatriz Rodríguez-Labajos) - Ecological Studies,Vol. 193, Biological Invasions, 2007.
As well interesting is deep investigation of the question by James T. Carlton
Deep Invasion Ecology and the Assembly of Communities
in Historical Time in Ecological Studies, Vol. 204 - Biological Invasions
in Marine Ecosystems, 2009 even may be more usefull for you!
i agree that time scale is the crucial point to evaluate invasion processes, and i also agree that invasion is not generally negative.
unoccupied niches and low diversity, as it is the case on isolated islands, would perhaps exibit the potential for introduced alien species to even improve ecosystem functioning and stability and ecosystem services.
however, islands are also sensitive for newcomers and biotic interactions (eg competition, herbivory etc) do not develop towards more or less stable states within short time periods.
in consequence, it is extremely difficult to project how an invaded system will respond to a new species that might even change its behaviour and ecological site preferences in a new setting (eg due to enemy release).
to sum up: time matters, but time scale for a system to adapt to a new species and for a species to adapt do a new environment differ substantially between months and centuries. i do not think that this can be generalized in terms of human time scales.
A large number of non-native species have been introduced to the host countries. However, the poor success of attempts to characterize invasive species and predict . species within these countries since it is not linear
Thank you for your reply dear colleague. Evidentially for a plant species, the transition from the introduced status to the status of a naturalized plant is complex. Very few researchers are interested because the ecological locks of the host territories are complex hierarchical and often difficult to decipher. I think introduced species are ecological disrupters that lead to ecosystem re-organization.
I agree with opinion of this very complex problem about introduction and invasion of plant species ...
For exemple,
Do we need of bush Robinia pseudoacacia L. in the steppe regions of the south Russia and Europe? This Njrd american plants is very like in the steppe. So, I dont know his négative effect in the 20 s
See also
The paradox of alien invasive species: negative and positive effects on ...
Nonetheless, along with negative effects, invasions can also have positive effects on ... 44. 3.2.2. Positive effects of invasive alien plants species on ecosystems.
The most horrible thing is nobody can stop these invasions since so many plant and animal species are being spread by human vector everywhere. Occasionally or intentionally.
A bad example i introduction of Tilapia or Ampullariidae Apple snails to almost any of water-bodies in SE Asia and Papuan region
I see that you are interested mostly in plants on islands. Clearly in the case of oceanic islands around the world most of these have been invaded significantly in the last 50-150 years. There is a large literature on lag-times. I will highlight two:
Kowarik, Ingo. "Time lags in biological invasions with regard to the success and failure of alien species." Time lags in biological invasions with regard to the success and failure of alien species. (1995): 15-38.
Daehler, Curtis C. "Short lag times for invasive tropical plants: evidence from experimental plantings in Hawai'i." PLoS One 4.2 (2009): e4462.
So for woody plants lag times between introduction and significant spread or impacts commonly range around 20-30 years for tropical systems, up to over a hundred for woody plants in temperate areas. It appears though that its largely a perception problem, with even a doubling of the population in a short period of time being largely imperceptible to people without active collection of data.
If anything island invasions are the most problematic because the floras have high levels of endemism, and are subject to destruction and introductions. So I disagree with the above comment that "invasion is not generally negative". Invasive plants generally lead to biodiversity reductions in a patchy way such that you can show diversity reductions at the patch level, but for the world scale few if any invasive plant can be unequivocally proven, and usually browsers and habitat destruction would be implicated too.
The number of extinctions from introduced predators and browsers on islands is huge....
Blackburn, Tim M., et al. "Avian extinction and mammalian introductions on oceanic islands." Science 305.5692 (2004): 1955-1958.
It's important to remember the difference between introduced and invasive - many introduced species do not exhibit negative effects on recipient ecosystems. I must point out that invasive species are termed so because of their negative implications. There is a body of evidence of the impacts of invasive species (e.g. decreased biodiversity, loss of rare species, degraded habitat, reduced ecological resilience, deminished ecosystem services).
However, across large timescales spanning hundreds of years, the outcomes of such invasions are not entirely clear; mainly because we don't live that long! I think it is important to consider that we have an intrinsic responsibility to mediate our ecological impacts, even if an invaded ecosystem might recover over several hundreds of years.
The creation of novel ecosystems as a result of species introductions is one thing; but is a vast monoculture of one invasive species comparable? It is interesting to see the development of this field over time.
Yes, indeed, I agree with Sophie. Even smtms hardly differ the difference exists. But in long term periods as well invasive can be natural. Yes, mankind can prepare perfect conditions for penetration of some kinds of species but it happened that Nature as well. I mean catastrophic events.
Some philosophy: How to classify the movement of human over the Bering bridge and colonization of Southern America that produce invasion of lie from a man for some species of monkey. Is that natural or man-caused? How to differ? And viruses from African species vice-versa... ? I suppose that some species of human disappear due to epidemic influence of some infections! Is that natural? I think so. Nature is protecting itself by all possible ways.
Invasive plants on islands is almost impossible (again let's see the case of Isla choros in Chile). Just in case, is working on the island Chañaral the eradication of rabbits.
CONAF - CHILE is studying options to eradicate invasive plants from these islands