Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs

Philip W. Lambdon 1 2 , Petr Pyšek 3 4 , Corina Başnou 5 , Martin Hejda 3 4 , Margarita Arianoutsou 6 , Franz Essl 7 , Vojtěch Jarošík 3 4 , Jan Pergl 3 , Marten Winter 8 , Paulina Anastasiu 9 , Pavlos Andriopoulos 6 , Ioannis Bazos 6 , Giuseppe Brundu 10 , Laura Celesti-Grapow 11 , Philippe Chassot 12 , Pinelopi Delipetrou 13 , Melanie Josefsson 14 , Salit Kark 15 , Stefan Klotz 8 , Yannis Kokkoris 6 , Ingolf Kühn 8 , Hélia Marchante 16 , Irena Perglová 3 , Joan Pino 5 , Montserrat Vilà 17 , Andreas Zikos 6 , David Roy 1 & Philip E. Hulme 18


  1. Centre for Ecology and Hydrology, Hill of Brathens, Banchory, Aberdeenshire AB31 4BW, Scotland
  2. Kew Herbarium, Royal Botanic Gardens Kew, Richmond, Surrey, TW9 3AB, United Kingdom
  3. Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
  4. Department of Ecology, Faculty of Science, Charles University, Viničná 7, CZ-128 01 Praha 2, Czech Republic
  5. Center for Ecological Research and Forestry Applications, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
  6. University of Athens, Faculty of Biology, Department of Ecology & Systematics, 15784 Athens, Greece
  7. Federal Environment Agency, Department of Nature Conservation, Spittelauer Lände 5, 1090 Vienna, Austria
  8. Helmholtz Centre for Environmental Research – UFZ, Department of Community Ecology, Theodor-Lieser- Str. 4, D-06120 Halle, Germany
  9. University of Bucharest, Faculty of Biology, Department of Botany & Microbiology, Aleea Portocalelor 1-3, 060101 Bucharest, Romania
  10. Department of Botany and Plant Ecology, University of Sassari, Italy
  11. Department of Plant Biology, Sapienza University of Rome, piazzale Aldo Moro 5, I-00185 Rome, Italy
  12. UMR1210 Biologie et Gestion des Adventices, INRA-ENESAD-Université de Bourgogne, 17 rue Sully, BP 86510, 21065 Dijon CEDEX, France
  13. University of Athens, Faculty of Biology, Department of Botany, 15784 Athens, Greece
  14. Swedish Environmental Protection Agency, Uppsala, Sweden
  15. The Biodiversity Research Group, Department of Evolution, Systematics and Ecology, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
  16. Department of Pure and Environmental Sciences, Escola Superior Agrária de Coimbra, Bencanta 3040-316, Coimbra, Portugal
  17. Estación Biológica de Dońana (EBD-CSIC), Avd/María Luisa s/n, Pabellón del Perú, 41013 Sevilla, Spain
  18. National Centre for Advanced Bio-Protection Technologies, PO Box 84, Lincoln University, Canterbury, New Zealand

PDF Appendices


The paper provides the first estimate of the composition and structure of alien plants occurring in the wild in the European continent, based on the results of the DAISIE project (2004–2008), funded by the 6th Framework Programme of the European Union and aimed at “creating an inventory of invasive species that threaten European terrestrial, freshwater and marine environments”. The plant section of the DAISIE database is based on national checklists from 48 European countries/regions and Israel; for many of them the data were compiled during the project and for some countries DAISIE collected the first comprehensive checklists of alien species, based on primary data (e.g., Cyprus, Greece, F. Y. R. O. Macedonia, Slovenia, Ukraine). In total, the database contains records of 5789 alien plant species in Europe (including those native to a part of Europe but alien to another part), of which 2843 are alien to Europe (of extra-European origin). The research focus was on naturalized species; there are in total 3749 naturalized aliens in Europe, of which 1780 are alien to Europe. This represents a marked increase compared to 1568 alien species reported by a previous analysis of data in Flora Europaea (1964–1980). Casual aliens were marginally considered and are represented by 1507 species with European origins and 872 species whose native range falls outside Europe. The highest diversity of alien species is concentrated in industrialized countries with a tradition of good botanical recording or intensive recent research. The highest number of all alien species, regardless of status, is reported from Belgium (1969), the United Kingdom (1779) and Czech Republic (1378). The United Kingdom (857), Germany (450), Belgium (447) and Italy (440) are countries with the most naturalized neophytes. The number of naturalized neophytes in European countries is determined mainly by the interaction of temperature and precipitation; it increases with increasing precipitation but only in climatically warm and moderately warm regions. Of the nowadays naturalized neophytes alien to Europe, 50% arrived after 1899, 25% after 1962 and 10% after 1989. At present, approximately 6.2 new species, that are capable of naturalization, are arriving each year. Most alien species have relatively restricted European distributions; half of all naturalized species occur in four or fewer countries/regions, whereas 70% of non-naturalized species occur in only one region. Alien species are drawn from 213 families, dominated by large global plant families which have a weedy tendency and have undergone major radiations in temperate regions (Asteraceae, Poaceae, Rosaceae, Fabaceae, Brassicaceae). There are 1567 genera, which have alien members in European countries, the commonest being globally-diverse genera comprising mainly urban and agricultural weeds (e.g., Amaranthus, Chenopodium and Solanum) or cultivated for ornamental purposes (Cotoneaster, the genus richest in alien species). Only a few large genera which have successfully invaded (e.g., Oenothera, Oxalis, Panicum, Helianthus) are predominantly of non-European origin. Conyza canadensis, Helianthus tuberosus and Robinia pseudoacacia are most widely distributed alien species. Of all naturalized aliens present in Europe, 64.1% occur in industrial habitats and 58.5% on arable land and in parks and gardens. Grasslands and woodlands are also highly invaded, with 37.4 and 31.5%, respectively, of all naturalized aliens in Europe present in these habitats. Mires, bogs and fens are least invaded; only approximately 10% of aliens in Europe occur there. Intentional introductions to Europe (62.8% of the total number of naturalized aliens) prevail over unintentional (37.2%). Ornamental and horticultural introductions escaped from cultivation account for the highest number of species, 52.2% of the total. Among unintentional introductions, contaminants of seed, mineral materials and other commodities are responsible for 1091 alien species introductions to Europe (76.6% of all species introduced unintentionally) and 363 species are assumed to have arrived as stowaways (directly associated with human transport but arriving independently of commodity). Most aliens in Europe have a native range in the same continent (28.6% of all donor region records are from another part of Europe where the plant is native); in terms of species numbers the contribution of Europe as a region of origin is 53.2%. Considering aliens to Europe separately, 45.8% of species have their native distribution in North and South America, 45.9% in Asia, 20.7% in Africa and 5.3% in Australasia. Based on species composition, European alien flora can be classified into five major groups: (1) north-western, comprising Scandinavia and the UK; (2) west-central, extending from Belgium and the Netherlands to Germany and Switzerland; (3) Baltic, including only the former Soviet Baltic states; (4) east-central, comprizing the remainder of central and eastern Europe; (5) southern, covering the entire Mediterranean region. The clustering patterns cut across some European bioclimatic zones; cultural factors such as regional trade links and traditional local preferences for crop, forestry and ornamental species are also important by influencing the introduced species pool. Finally, the paper evaluates a state of the art in the field of plant invasions in Europe, points to research gaps and outlines avenues of further research towards documenting alien plant invasions in Europe. The data are of varying quality and need to be further assessed with respect to the invasion status and residence time of the species included. This concerns especially the naturalized/casual status; so far, this information is available comprehensively for only 19 countries/regions of the 49 considered. Collating an integrated database on the alien flora


alien plants, biogeographical pattern, donor regions, Europe, habitat affinity, naturalization, neophytes, plant invasions, residence time, temporal trends

How to cite

Lambdon P. W., Pyšek P., Basnou C., Hejda M., Arianoutsou M., Essl F., Jarošík V., Pergl J., Winter M., Anastasiu P., Andriopoulos P., Bazos I., Brundu G., Celesti-Grapow L., Chassot P., Delipetrou P., Josefsson M., Kark S., Klotz S., Kokkoris Y., Kühn I., Marchante H., Perglová I., Pino J., Vila M., Zikos A., Roy D. & Hulme P. E. (2008) Alien flora of Europe: species diversity, temporal trends, geographical patterns and research needs. – Preslia 80: 101149