Literaturdatenbank
Literaturdatenbank |
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Wittenberg, R., Kenis, M., Blick, T., Hänggi, A., Gassmann, A., & Weber, E. (2005). An inventory of alien species and their threat to biodiversity and economy in switzerland CABI Bioscience Switzerland Centre report to the Swiss Agency for Environment, Forests and Landscape.
Added by: Sarina Wunderlich (27 Nov 2011 14:28:23 UTC) |
| Resource type: Report/Documentation BibTeX citation key: Wittenberg2005 View all bibliographic details  |
Categories: General Keywords: Emydidae, Emys, Emys orbicularis, Europa = Europe, Habitat = habitat, invasive Arten = invasive species, Schildkröten = turtles + tortoises, Trachemys, Trachemys scripta Creators: Blick, Gassmann, Hänggi, Kenis, Weber, Wittenberg Publisher: CABI Bioscience Switzerland Centre report to the Swiss Agency for Environment, Forests and Landscape |
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| Abstract |
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Mit der zunehmenden Globalisierung nimmt auch der Handel, Verkehr und das Reisen zu und führt zu einer noch nie dagewesenen Homogenisierung der Biodiversität; Organismen werden über die natürlichen Grenzen hinaus transportiert. Einige dieser Neuankömmlinge können sich etablieren, und wiederum einige von diesen werden invasiv und bedrohen die einheimische Vielfalt, richten wirtschaftlichen Schaden an oder schädigen die menschliche Gesundheit. Dieser Bericht über die gebietsfremden Arten der Schweiz listet über 800 etablierte gebietsfremde Arten auf und stellt die 107 Problemarten in Datenblättern vor: fünf Säugetiere, vier Vögel, ein Reptil, drei Amphibien, sieben Fische, vier Weichtiere, 16 Insekten, sechs Krebstiere, drei Spinnen, zwei ‘Würmer’, sieben Pilze, ein Bakterium und 48 Pflanzen. Das erste Kapitel erläutert einige allgemeine Einführungswege, negative Einflüsse und Gegenmassnahmen und gibt Vorschläge für den Umgang mit gebietsfremden Arten. Der Hauptteil besteht aus den Kapiteln zu den einzelnen taxonomischen Gruppen. Die Listen werden begleitet durch einen erläuternden Text, die Datenblätter stellen die Problemarten vor und schliesslich wird eine Auswertung der Situation, der Auswirkungen, der Einführungswege, mögliche Gegensteuerungsmassnahmen und Empfehlungen zu den jeweiligen taxonomischen Gruppen gegeben. Die Datenblätter bieten Information zu Taxonomie, Beschreibung, Ökologie, Herkunft, Einführungswege, Verbreitung, Auswirkungen, Ansätze zur Gegensteuerung und ein Literaturverzeichnis. Reptiles - Reptilia Three snake species have been relocated within Switzerland, from southern locations to colder, northern localities. Two of these relocations were very local. The re-introduction of the European pond terrapin used alien genetic material. The only alien reptile species in Switzerland as a country are aquatic turtles released from aquariums, but they seem not to have established populations yet (Table 2.4). The case of the Italian wall lizard (Podarcis sicula (Rafinesque-Schmaltz)) in Switzerland is rather mysterious (Hofer et al., 2001). It is not known whether the species is native or alien nor is it proven that an established population exists at all. Since specimens were found along the railway tracks in the Ticino, an accidental introduction from Italy seems likely. The dice snake (Natrix tessellata (Laurenti)) is one of the most endangered snakes in Switzerland, because it is at the north-western limit of its range (thus it is naturally rare). It is native to the Ticino, but was released north of the Alps at several lakes (Gruschwitz et al., 1999). Although it is rare in Switzerland, it should not be relocated to the north of the Alps. At the Lac de Genève, where it now occurs together with another rare snake species, the viperine snake (Natrix maura (L.)), it is probably competing with the native species for food and habitat, since the two species have a rather similar biology, one occurring in south-western Europe and the other in south-eastern Europe (Hofer et al., 2001). Small populations of the western whip snake (Coluber viridiflavus (Lacépède)) might have established at the Neuenburgersee and in the Valais, from specimens collected in the Ticino and released in these areas. The impacts of these populations are probably negligible and the populations themselves might not persist. Populations of the Aesculapian snake (Elaphe longissima (Laurenti)) at the Neuenburgersee and Bieler See may have originated in the same way and again have little impact. The latter species does seem to be established (Hofer et al., 2001). The status of the European pond terrapin (Emys orbicularis (L.)) in Switzerland is not yet resolved (Hofer et al., 2001). Some populations might still be native, but there were many re-introductions of the species. In most instances the origin of the specimens released is not known, but releases of non-native material could lead to genetic introgression into possibly surviving native populations. However, this concern remains hypothetical because of the lack of knowledge of the status of extant populations. The North American red-eared slider (Trachemys scripta (Seidel)) (see Fact Sheet) is representative here of a guild of potential IAS - aquatic turtles from several genera. In past years, several countries restricted the importation of this species, because of the potential threat. However, this merely leads to a shift to other species by the aquarium trade. The red-eared slider is still the species most often found in the wild in high numbers and many places, although, because of the direct releases in parks etc., the species is predominantly recorded around agglomerations (Geiger and Waitzmann, 1996). The redeared slider is probably not yet established in the wild in Switzerland, but this might change through adaptation and future releases of specimens from a more northern natural distribution in North America. Reproduction has been repeatedly observed in areas of Europe with a Mediterranean climate. However, even without reproduction, the populations in certain areas of Switzerland are extremely high owing to frequent releases and the longevity of the species. Therefore there is the potential for native biodiversity to be affected, even if reproduction fails. A recent study by Cadi and Joly (2004) found both weight loss and high mortality in the native turtle Emys orbicularis (L.) in mixed groups and argues for applying a precautionary principle. The introduced species also outcompetes the native turtle for preferred basking places (Cadi and Joly, 2003). The red-eared slider is one of the species mentioned in the Recommendations of the Bern Convention, as described above. Since no alien reptile species has established populations in Switzerland, no general pattern can be discussed here, except to note that the situation in neighbouring countries is rather similar. Reptiles depend to a large extent on climate, especially temperature, because they can regulate their body temperature only to a certain degree. Thus, tropical and subtropical species, which are most frequently kept in terrariums, are not of concern, apart from escapes of the occasional crocodilian or dangerous snake. However, this is more a matter of interest for the media than a true threat. A real concern for native biodiversity are species from North America and east Asia (China), mainly turtles, which could become established in the Swiss climate.
Added by: Sarina Wunderlich |