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                                                                               Mammals from Mediterranean islands  7

                                 Table 3 Mammal extinction (top) and introduction (bottom) due to anthropogenic actions in the last two
                                 centuries on the western Mediterranean islands. The extinction ratio (13 species in 10 islands = 1.33) is
                                 equivalent to the introduction (nine species in seven islands = 1.29). Sicily, the largest and nearest to mainland,
                                 is the most active island (seven extinctions, four introductions) in this process of recent faunal turnover

                                 Species                 Island                            Time

                                   Arvicola terrestris   Sicily                            1950?
                                   Ursus arctos          Corsica                           Around 1700
                                   Lepus corsicanus      Elba                              1920–50
                                   Lepus capensis        Minorca, Ibiza                    Last 100 years
                                   Lutra lutra           Sicily                            1950?
                                   Martes foina          Ibiza                             Last 100 years
                                   Martes martes         Montecristo, Giglio, Pianosa      1920–50
                                   Canis lupus           Sicily                            1920–30
                                   Sus scrofa            Sicily                            1860–80
                                   Cervus elaphus        Sicily, Corsica, Marettimo Favignana  Last 150 years
                                   Dama dama             Sicily, Sardegna, Ibiza           Last 200 years
                                   Caproleus caproleus   Sicily                            Around 1800
                                   Vulpes vulpes         Lampedusa                         Around 1800 (introduction)
                                   Lepus europaeus       Elba, Sicily (tentative)          Around 1960
                                   Hystrix cristata      Elba                              Around 1980
                                   Sciurus vulgaris      Ste Marguerite                    Not known
                                   Sus scrofa            Elba, Sicily, Marettimo           1960–70
                                   Cervus elaphus        Corsica                           Around 1980
                                   Cervus nippon         Porquerolles                      Not known
                                   Dama dama             Elba, Sicily                      1960–70
                                   Ovis orientalis       Marettimo, Capraia, Elba          1960–80
                                   Myocastor coypus      Sicily                            Around 1980

                                 analyses failed to find any significant relationship  show a comparatively high genetic diversity within
                                 between species richness and distance from the  island populations compared to mainland ones
                                 mainland. The continental nature and the presence  (Frankham, 1997; Cheylan  et al., 1998). How-
                                 of some large and distant islands (e.g. Corsica,  ever, we caution against making a generalization
                                 Sardinia, Crete and Cyprus) may explain this.  as no genetic information on other mammal
                                   Three of the most successful invaders are Rattus  species is available.
                                 rattus,  Mus musculus and  Oryctolagus cuniculus,
                                 and all are closely associated with humans. In
                                 this respect, humans can be viewed as direct or
                                 indirect ‘mammal carriers’, sometimes also  pre-  This study is supported by the Institut Français
                                 paring the arena for transported mammals (i.e. by  de la Biodiversité. We thank two referees for
                                 modifying the environment by fire, deforestation,  their helpful comments.
                                 cultivation and hunting of native species). Never-
                                 theless, imported species may have to be highly
                                 adaptive in order to survival in the often harsh  REFERENCES
                                 ecosystems of small islands (Cheylan, 1988).
                                                                          Agnesi, V., Macaluso, T. & Masini, F. (1997)
                                   There are presently insufficient data to test
                                                                            L’ambiente e il clima della Sicilia nell’ultimo
                                 the role of genetics. However, it is  noticeable  milione di  anni.  Prima Sicilia alle Origini della
                                 that two species found on the smallest islands  Società Siciliana (ed. by S. Tusa), Ediprint, Palermo,
                                 (R. rattus and  M. musculus) are those which  Italy, pp. 31–54.
                                 © 2002 Blackwell Science Ltd, Diversity and Distributions, 8, 1–9
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