Ulrich, W., Nicolaus Copernicus University Toruń, Toruń, Poland
Soliveres, S., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain, Institute of Plant Sciences, University of Bern, Bern, Switzerland
Maestre, F.T., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
Gotelli, N.J., Department of Biology, University of Vermont, Burlington, United States
Quero, J.L., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain, Departamento de Ingeniería Forestal, Escuela Técnica Superior de Ingeniería Agronómica y de Montes, Universidad de Córdoba, Córdoba, Spain
Delgado-Baquerizo, M., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain, Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Sevilla, Spain
Bowker, M.A., School of Forestry, Northern Arizona University, Flagstaff, United States
Eldridge, D.J., School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
Ochoa, V., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
Gozalo, B., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
Valencia, E., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
Berdugo, M., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
Escolar, C., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
García-Gómez, M., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain, Departamento de Ingeniería y Morfología del Terreno, Universidad Politécnica de Madrid, Madrid, Spain
Escudero, A., Departamento de Biología y Geología, Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Spain
Prina, A., Facultad de Agronomía, Universidad Nacional de La Pampa, La Pampa, Argentina
Alfonso, G., Facultad de Agronomía, Universidad Nacional de La Pampa, La Pampa, Argentina
Arredondo, T., Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, San Luis Potosí, Mexico
Bran, D., Instituto Nacional de Tecnología Agropecuaria, Estación Experimental San Carlos de Bariloche, Bariloche, Argentina
Cabrera, O., Instituto de Ecología, Universidad Técnica Particular de Loja, Loja, Ecuador
Cea, A.P., Departamento de Biología, Universidad de La Serena, La Serena, Chile
Chaieb, M., UR Plant Biodiversity and Ecosystems in Arid Environments, Faculty of Sciences, University of Sfax, Sfax, Turkey
Contreras, J., Departamento de Suelos, Universidad Centroccidental Lizandro Alvarado, Barquisimeto, Estado Lara, Venezuela
Derak, M., Direction Regionale des Eaux et Forets et de la Lutte Contre la Désertification du Rif, Tétouan, Morocco
Espinosa, C.I., Instituto de Ecología, Universidad Técnica Particular de Loja, Loja, Ecuador
Florentino, A., Instituto de Edafología, Facultad de Agronomía, Universidad Central de Venezuela, Estado Aragua, Venezuela
Gaitán, J., Instituto Nacional de Tecnología Agropecuaria, Estación Experimental San Carlos de Bariloche, Bariloche, Argentina
Muro, V.G., IANIGLA, CCT Mendoza, Mendoza, Argentina
Ghiloufi, W., UR Plant Biodiversity and Ecosystems in Arid Environments, Faculty of Sciences, University of Sfax, Sfax, Turkey
Gómez-González, S., Departamento de Ciencias Básicas, Laboratorio de Genómica y Biodiversidad, Universidad del Bío-Bío, Chillán, Chile, Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile
Gutiérrez, J.R., Departamento de Biología, Universidad de La Serena, La Serena, Chile, Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile, Instituto de Ecología y Biodiversidad, Santiago, Chile
Hernández, R.M., Laboratorio de Biogeoquímica, Centro de Agroecología Tropical, Universidad Experimental Simón Rodríguez, Caracas, Venezuela
Huber-Sannwald, E., Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, San Luis Potosí, Mexico
Jankju, M., Department of Range and Watershed Management, Ferdowsi University of Mashhad, Mashhad, Iran
Mau, R.L., Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, United States
Hughes, F.M., Departamento de Biologia, Universidade Federal de Minas Gerais, Minas Gerais, Brazil
Miriti, M., Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, United States
Monerris, J., Département des Sciences Biologiques, Université du Québec à Montréal Pavillon des sciences biologiques, Montréal, Canada
Muchane, M., Zoology Department of the National Museums of Kenya, Nairobi, Kenya
Naseri, K., Department of Range and Watershed Management, Ferdowsi University of Mashhad, Mashhad, Iran
Pucheta, E., Departamento de Biología, Facultad de Ciencias Exactas Físicas y Naturales, Universidad Nacional de San Juan, San Juan, Argentina
Ramírez-Collantes, D.A., Production Systems and the Environment Sub-Program, International Potato Center, Lima, Peru
Raveh, E., Department of Natural Resources and Citriculture, Agriculture Research Organization, Gilat Research Center, M.P. Negev 85280, Israel
Romão, R.L., Departamento de Ciencias Biológicas, Universidade Estadual de Feira de Santana, Feira de Santana, Brazil
Torres-Díaz, C., Departamento de Ciencias Básicas, Laboratorio de Genómica y Biodiversidad, Universidad del Bío-Bío, Chillán, Chile, Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile
Val, J., School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
Veiga, J.P., Departamento de Ecología Evolutiva, Museo Nacional de CCNN, Madrid, Spain
Wang, D., Institute of Grassland Science, Key Laboratory for Vegetation Ecology, Northeast Normal University, Changchun, Chile
Yuan, X., Institute of Grassland Science, Key Laboratory for Vegetation Ecology, Northeast Normal University, Changchun, Chile
Zaady, E., Department of Natural Resources and Citriculture, Agriculture Research Organization, Gilat Research Center, M.P. Negev 85280, Israel

Aim: Geographical, climatic and soil factors are major drivers of plant beta diversity, but their importance for dryland plant communities is poorly known. The aim of this study was to: (1) characterize patterns of beta diversity in global drylands; (2) detect common environmental drivers of beta diversity; and (3) test for thresholds in environmental conditions driving potential shifts in plant species composition. Location: Global. Methods: Beta diversity was quantified in 224 dryland plant communities from 22 geographical regions on all continents except Antarctica using four complementary measures: the percentage of singletons (species occurring at only one site); Whittaker's beta diversity, β(W); a directional beta diversity metric based on the correlation in species occurrences among spatially contiguous sites, β(R2); and a multivariate abundance-based metric, β(MV). We used linear modelling to quantify the relationships between these metrics of beta diversity and geographical, climatic and soil variables. Results: Soil fertility and variability in temperature and rainfall, and to a lesser extent latitude, were the most important environmental predictors of beta diversity. Metrics related to species identity [percentage of singletons and β(W)] were most sensitive to soil fertility, whereas those metrics related to environmental gradients and abundance [(β(R2) and β(MV)] were more associated with climate variability. Interactions among soil variables, climatic factors and plant cover were not important determinants of beta diversity. Sites receiving less than 178 mm of annual rainfall differed sharply in species composition from more mesic sites (> 200 mm). Main conclusions: Soil fertility and variability in temperature and rainfall are the most important environmental predictors of variation in plant beta diversity in global drylands. Our results suggest that those sites annually receiving c. 178 mm of rainfall will be especially sensitive to future climate changes. These findings may help to define appropriate conservation strategies for mitigating effects of climate change on dryland vegetation. © 2014 John Wiley & Sons Ltd.