1,2,3,4 Adriana Alzate
1,5,6, Roberto Rozzi
7 Julián A. Velasco
8 D. Ross Robertson
9 Alexander Zizka
10 Joseph A. Tobias
11,12 Adrian Hill
11,12 Christine D. Bacon
13 Thijs Janzen
14, 15 Loïc Pellissier
16 Fons van der Plas
10 James Rosindell
1,2,4, Renske E. Onstein

1. German Centre for Integrative Biodiversity Research (iDiv) Halle – Jena – Leipzig, Leipzig, Germany
2. Leipzig University, Leipzig, Germany
3. Aquaculture and Fisheries Group, Wageningen University and Research, Wageningen, The Netherlands
4. Naturalis Biodiversity Center, Leiden, the Netherlands
5. Central Repository of Natural Science Collections (ZNS), Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
6. Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany 
7. Instituto de Ciencias de la Atmósfera y Cambio Climático, Universidad Nacional Autónoma de México, Mexico City, Mexico 
8. Smithsonian Tropical Research Institute, Balboa, Panama
9. Department of Biology, Philipps-University Marburg, Marburg, Germany
10. Department of Life Sciences, Imperial College London, Ascot, United Kingdom
11. Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
12. Gothenburg Global Biodiversity Centre, Gothenburg, Sweden
13. Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
14. Ecosystems & Landscape Evolution, Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, Swiss Federal Institute of Technology, ETH Zurich, Zurich, Switzerland
15. Plant Ecology and Nature Conservation, Wageningen University and Research, Wageningen, The Netherlands 

Abstract

More than 40 thousand species of plants and animals are facing extinction worldwide. Range size is one of the strongest determinants of extinction risk, but the causes underlying the wide variation in natural range sizes remain poorly understood. Here, we investigate how species’ age is related to present-day range size for over 26,000 species of mammals, birds, reptiles, amphibians, reef fishes, and plants. We show that, on average, older species have larger ranges across all groups except for marine mammals, but the strength of the age-range size relationship depends on taxonomic scale. Furthermore, while our results confirm the well-established pattern of smaller range sizes for species restricted to islands (compared to mainland) or with limited dispersal abilities (compared to good dispersers), we show that the correlation between species age and range size is stronger in these groups, suggesting that island dynamics and dispersal ability modulate this relationship. Our study reveals that species with small ranges, and thus increased extinction risk, tend to be restricted to islands, are poor dispersers, or have recently evolved.