Island biogeography has traditionally focused primarily on abiotic drivers of colonization, extinction and speciation. However, establishment on islands could also be limited by biotic drivers, such as the absence of symbionts. Most plants, for example, form symbioses with mycorrhizal fungi, whose limited dispersal to islands could act as a colonization filter for plants. We tested this hypothesis using global-scale analyses of ~1.4 million plant occurrences, including ~200,000 plant species across ~1,100 regions. We find evidence for a mycorrhizal filter (that is, the filtering out of mycorrhizal plants on islands), with mycorrhizal associations less common among native island plants than native mainland plants. Furthermore, the proportion of native mycorrhizal plants in island floras decreased with isolation, possibly as a consequence of a decline in symbiont establishment. We also show that mycorrhizal plants contribute disproportionately to the classic latitudinal gradient of plant species diversity, with the proportion of mycorrhizal plants being highest near the equator and decreasing towards the poles. Anthropogenic pressure and land use alter these plant biogeographical patterns. Naturalized floras show a greater proportion of mycorrhizal plant species on islands than in mainland regions, as expected from the anthropogenic co-introduction of plants with their symbionts to islands and anthropogenic disturbance of symbionts in mainland regions. We identify the mycorrhizal association as an overlooked driver of global plant biogeographical patterns with implications for contemporary island biogeography and our understanding of plant invasions.

Centre of Biodiversity and Sustainable Land Use University of Goettingen Göttingen Germany

Departamento de Ciencias de la Vida Universidad de las Fuerzas Armadas ESPE Sangolquí Ecuador

Department of Biodiversity Macroecology and Biogeography University of Goettingen Göttingen Germany

Department of Biology University of Konstanz Konstanz Germany

Department of Biosciences University of Durham Durham UK

Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA

Department of Ecology Faculty of Science Charles University Prague Czech Republic

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

German Centre for Integrative Biodiversity Research Halle Jena Leipzig Leipzig Germany

Institute of Botany Department of Invasion Ecology Czech Academy of Sciences Průhonice Czech Republic

Kansas Biological Survey University of Kansas Lawrence KS USA

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

Citace poskytuje Crossref.org

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