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24 General Conclusion, or what Has to be Done now?
Wolfgang Nentwig
Now, after numerous experts have given their detailed and well-founded
statements on various aspects of biological invasions in this book, it is time to
settle back for a moment and to rethink this flood of information. Two points
come immediately to mind:
1. The number of alien and invasive species is still increasing, no change is
yet visible, many habitat modifications are irreversible, and earlier pristine
conditions of nature can no longer be restored.
2. There are many recommendations and conclusions which should be followed
as consequentially as possible – and as soon as possible – to mitigate
the impact of biological invasions. Most of these recommendations can be
attributed to one of the following five categories: scientific research, management,
technical solutions, legislation and administration, and socioeconomy,
including education of the public.
24.1 Need for more Research
Though alien species and biological invasions have become very topical in
recent years, it is astonishing (or, should I say, embarrassing) how limited our
knowledge still is. We lack information on the specific characteristics (traits)
of those species which become invasive, and we do not really know how successful
invaders differ from closely related non-invaders. This makes plausible
prognoses extremely difficult (if these will ever be possible) but it has also to
be stressed that explanation and prediction are two different things. We know
that it is unrealistic to expect to detect single characteristics, or even syndromes,
which fully explain invasiveness. Biological invasions are to a large
extent idiosyncratic, triggered by a huge variety of events and driven by specific
factors. A far more realistic approach, therefore, focuses on a complex
interaction of many factors, including species traits, environmental aspects
and human influence, which need to be more fully unravelled. Today, it is
Ecological Studies,Vol. 193
W. Nentwig (Ed.)
Biological Invasions
© Springer-Verlag Berlin Heidelberg 2007