One of the best-known general patterns in island biogeography is the species-isolation relationship (SIR), a decrease in the number of native species with increasing island isolation that is linked to lower rates of natural dispersal and colonization on remote oceanic islands. However, during recent centuries, the anthropogenic introduction of alien species has increasingly gained importance and altered the composition and richness of island species pools. We analyzed a large dataset for alien and native plants, ants, reptiles, mammals, and birds on 257 (sub) tropical islands, and showed that, except for birds, the number of naturalized alien species increases with isolation for all taxa, a pattern that is opposite to the negative SIR of native species. We argue that the reversal of the SIR for alien species is driven by an increase in island invasibility due to reduced diversity and increased ecological naiveté of native biota on the more remote islands.

Biodiversity Macroecology and Biogeography University of Goettingen 37077 Goettingen Germany

Centre for Invasion Biology Department of Botany and Zoology Stellenbosch University 7602 Matieland South Africa

Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto 4485 661 Vairão Portugal

Department of Biosciences Durham University DH1 3LE Durham United Kingdom

Department of Ecology Faculty of Science Charles University CZ 128 44 Prague Czech Republic

Division of Conservation Biology Vegetation and Landscape Ecology University of Vienna 1030 Vienna Austria

Division of Conservation Biology Vegetation and Landscape Ecology University of Vienna 1030 Vienna Austria;

Ecology University of Konstanz 78457 Konstanz Germany

Ecosystem Services and Management Program International Institute of Applied Systems Analysis 2361 Laxenburg Austria

German Centre for Integrative Biodiversity Research Halle Jena Leipzig 04103 Leipzig Germany

Institute of Botany Department of Invasion Ecology The Czech Academy of Sciences CZ 252 43 Průhonice Czech Republic

Manaaki Whenua Landcare Research 7640 Lincoln New Zealand

Okinawa Institute of Science and Technology Graduate University Onna 904 0495 Okinawa Japan

School of Biological Sciences and Centre for Conservation Science and Technology The University of Adelaide North Terrace Adelaide SA 5005 Australia

School of Biological Sciences The University of Hong Kong Pok Fu Lam Hong Kong SAR China

Senckenberg Biodiversity and Climate Research Centre 60325 Frankfurt am Main Germany

Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation Taizhou University 318000 Taizhou China

Zoologisches Forschungsmuseum Alexander Koenig Museumsmeile Bonn 53113 Bonn Germany

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Naturalized alien floras still carry the legacy of European colonialism

Effects of land-use change and related pressures on alien and native subsets of island communities

Economic use of plants is key to their naturalization success

Drivers of the relative richness of naturalized and invasive plant species on Earth