Human-mediated transport beyond biogeographic barriers has led to the introduction and establishment of alien species in new regions worldwide. However, we lack a global picture of established alien species richness for multiple taxonomic groups. Here, we assess global patterns and potential drivers of established alien species richness across eight taxonomic groups (amphibians, ants, birds, freshwater fishes, mammals, vascular plants, reptiles and spiders) for 186 islands and 423 mainland regions. Hotspots of established alien species richness are predominantly island and coastal mainland regions. Regions with greater gross domestic product per capita, human population density, and area have higher established alien richness, with strongest effects emerging for islands. Ants and reptiles, birds and mammals, and vascular plants and spiders form pairs of taxonomic groups with the highest spatial congruence in established alien richness, but drivers explaining richness differ between the taxa in each pair. Across all taxonomic groups, our results highlight the need to prioritize prevention of further alien species introductions to island and coastal mainland regions globally.

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This research benefited from support from the European Commission (COST Action TD1209). The Deutsche Forschungsgemeinschaft supported H.S. (DFG, grant SE 1891/2-1), M.v.K. (KL 1866/9-1) and M.W. (FZT 118), the Austrian Science Foundation supported F.E., B.L. and D.M. (FWF, grant I2086-B16). P.P. and J.P. were supported by the Academy of Sciences of the Czech Republic (no. RVO 67985939), Praemium Academiae award to P.P. and Czech Science Foundation (project no. 14-36079G). C. Capinha was supported by a postdoctoral grant from the Portuguese Foundation for Science and Technology (FCT/MCTES) and POPH/FSE (EC) grant SFRH/BPD/84422/2012. E.G.-B. was supported by the Spanish Ministry of Economy and Competitiveness (projects CGL2013-43822-R and CGL2015-69311-REDT). C.M. was supported by the Volkswagen Foundation through a Freigeist Fellowship.

Author information


  1. Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.

    • Wayne Dawson
  2. Division of Conservation Biology, Vegetation and Landscape Ecology, University Vienna, Rennweg 14, A-1030 Vienna, Austria.

    • Dietmar Moser
    • , Bernd Lenzner
    •  & Franz Essl
  3. Ecology, Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz, D-78457, Germany.

    • Mark van Kleunen
  4. Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China.

    • Mark van Kleunen
  5. Biodiversity, Macroecology & Biogeography, University of Goettingen, Büsgenweg 1, D-37077 Göttingen, Germany.

    • Holger Kreft
    •  & Patrick Weigelt
  6. Institute of Botany, Department of Invasion Ecology, The Czech Academy of Sciences, CZ-25243 Průhonice, Czech Republic.

    • Jan Pergl
    •  & Petr Pyšek
  7. Department of Ecology, Faculty of Science, Charles University, Viničná 7, CZ-12844 Prague, Czech Republic.

    • Petr Pyšek
  8. Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.

    • Petr Pyšek
    •  & Franz Essl
  9. German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany.

    • Marten Winter
  10. Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London Gower Street, London WC1E 6BT, UK.

    • Tim M. Blackburn
    •  & Ellie E. Dyer
  11. Institute of Zoology, Zoological Society of London Regent’s Park, London NW1 4RY, UK.

    • Tim M. Blackburn
  12. School of Biological Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia.

    • Tim M. Blackburn
  13. School of Biological Sciences and Centre for Conservation Science and Technology (CCoST), The University of Adelaide, North Terrace, South Australia 5005, Australia.

    • Phillip Cassey
    • , Sally L. Scrivens
    •  & Pablo García-Díaz
  14. Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Okinawa, 904-0495, Japan.

    • Evan P. Economo
  15. School of Biological Sciences, The University of Hong Kong, Kadoorie Biological Sciences Building, Pok Fu Lam Road, Hong Kong SAR, China.

    • Benoit Guénard
  16. CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Cátedra Infraestruturas de Portugal-Biodiversidade, Universidade do Porto, Campus Agrário de Vairão, P-4485-661 Vairão, Portugal.

    • César Capinha
  17. Zoologisches Forschungsmuseum Alexander Koenig, Adenauerallee 160, D-53113 Bonn, Germany.

    • César Capinha
  18. Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.

    • Hanno Seebens
  19. Landcare Research, PO Box 69040, Lincoln 7640, New Zealand.

    • Pablo García-Díaz
  20. Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, CH-3012 Bern, Switzerland.

    • Wolfgang Nentwig
  21. GRECO, Institute of Aquatic Ecology, University of Girona, 17003 Girona, Catalonia, Spain.

    • Emili García-Berthou
  22. FishBase Information and Research Group, Inc., Khush Hall, International Rice Research Institute, Los Baños, Laguna, Philippines.

    • Christine Casal
  23. Department of Biological Sciences, University of Toronto, 1265 Military Trail, M1C 1A4 Toronto, Ontario, Canada.

    • Nicholas E. Mandrak
  24. United States Geological Survey, Nonindigenous Aquatic Species Program, Wetlands and Aquatic Research Center, 7920 NW 71st Street, 32653 Gainesville, Florida, USA.

    • Pam Fuller
  25. Macroecology and Society, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany.

    • Carsten Meyer


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The GloNAF core team (M.v.K., P.P., W.D., F.E., J.P., M.W., H.K. and P.W.), T.M.B., H.S. and B.L. conceived the idea; W.D. coordinated data collation, and designed and led the analyses and writing with major inputs from F.E., D.M. M.v.K., P.P., H.K., M.W., J.P. and P.W., and further inputs from all other authors. Data were contributed by the GloNAF database for vascular plants, E.P.E. and B.G. for ants, C. Capinha, F.E., H.S. and P.G.-D. for amphibians and reptiles, T.M.B. and E.E.D. for birds, C. Casal, E.G.-B., P.F. and N.E.M. for fishes, P.C. and S.L.S for mammals, and W.N. for spiders. D.M. collected and calculated data on region area and sampling effort. C.M. contributed data on completeness of native species richness inventories.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Wayne Dawson.

Supplementary information

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  1. 1.

    Supplementary Information

    Three Supplementary Figures; six Supplementary Tables