Neophytes in Austria: Habitat preferences and ecological effects

Alien species are acknowledged as a major threat to the conservation of global biodiversity (e.g. Sala et al. 2000; McNeely et al. 2001; Cronk & Fuller 2001; Sukopp 2002; Cox 2004). While detailed case studies of alien species are necessary to understand the invasion processes, inventories of alien species have proven to be useful, especially for deriving empirical hypotheses that can be tested by experimental methods and for describing invasion patterns at various scales, from global to local (Kuhn & Klotz 2003; Pysek et al. 2003). Human activities such as agriculture, aquaculture, forestry, transportation, recreation and building activities promote the intentional and accidental spread of species across their natural boundaries. Trade and passenger traffic have increased enormously during the past centuries and especially during the last decades; this has accelerated the introduction of alien species (Jager 1988; Kowarik 2003). To face the conservational and economic problems caused by alien species, international cooperation is needed. Therefore, the Convention of Biological