View - ResearchGate

15 Effects of Invasive Non-Native Species
on the Native Biodiversity in the River Rhine
Bruno Baur and Stephanie Schmidlin
15.1 Introduction
Besides habitat degradation, the impacts of non-native invasive species are a
major cause of extinction of native species (Groombridge 1992; Sala et al.
2000; Cox 2004). Invading species may interact with the native biota in a variety
of ways, for example, by competition, predation, parasitism, disease and
hybridization. Some non-native species may enter an ecosystem and remain
at low densities for many years or disappear gradually whereas others might
have a profound impact on the existing community by changing species
abundance, food webs and energy fluxes. Linking invasion patterns with
interspecific processes is often difficult but such information is crucial to predict
the impacts of non-native species on the biodiversity of newly invaded
locations (Moyle and Light 1996; Williamson 1996, 1999).
The Convention on Biodiversity exhorts the contracting parties to “prevent
the introduction, control or eradicate those alien species which threaten
ecosystems, habitats or species” (Glowka et al. 1994). To implement these
directives, detailed knowledge on native biodiversity, and on potential interactions
between invading non-native species and native species is required.
Compared to the attention paid to extinctions in terrestrial habitats, much
less focus has been given to species loss in freshwater ecosystems, and this
despite several studies demonstrating a growing number of extinctions in
freshwater animal species (fishes, molluscs, crayfishes; e.g. Kaufman 1992;
Strayer 1999; Ricciardi and Rasmussen 1999).
This chapter examines the impact of invasive non-native species on the
biodiversity in the river Rhine. The occurrence and spread of non-native
species are relatively well documented in the Rhine (e.g. Tittizer et al. 2000;
Geitler et al. 2002; Rey et al. 2004). Quantitative studies on changes in abundance
of non-native species and on species composition of native communities
complement these reports (e.g. Van den Brink et al. 1990, 1996; Haas et
Ecological Studies,Vol. 193
W. Nentwig (Ed.)
Biological Invasions
© Springer-Verlag Berlin Heidelberg 2007