Introduction to the List of Alien Taxa

The list of alien taxa presented in this book is an extraction from the European Alien Species Database developed within the course of the DAISIE project. The overall number of alien species registered in the DAISIE database by February 2007 is 10,771. The alien species list represents a broad taxonomic spectrum of terrestrial and aquatic free living and parasitic organisms. In total, there are 46 phyla, 101 classes, 334 orders, 1,267 families and 4,492 genera recorded in the database. The phyla of Magnoliophytina, Arthropoda and Chordata contain the highest numbers of the alien species: 61%, 23% and 6%, accordingly (Fig. 10.1). Most of the phyla (28) contain less than 10 recorded species; and there are 10 phyla represented by only one recorded alien species.

The list as it is printed in this book includes only taxonomic information on recorded alien species, subspecies and hybrids. The DAISIE database (www. europe-aliens.org), however, contains documented introduction records of the alien taxa for 71 terrestrial and nine marine regions of Europe, the Levantine Basin and the North African coast of the Mediterranean Sea. These regions mostly match political borders of countries as they are known today. However it needs to be mentioned that where data were available at a finer political or biogeographic level these are also presented e.g., the administrative regions of the United Kingdom (Wales, Scotland, England, northern Ireland) or islands like Corsica, Sicily, Crete, Greenland or Svalbard. The total number of species-region records is 45,211, including 41,347 records for terrestrial regions and 3,864 for aquatic regions (Table 10.1).