title: Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area.
abstract: Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees-1year-1) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future.
authors.affiliation: Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.
authors.forename: Sarah
authors.identifier: 0000-0001-9104-7936
authors.initials: S
authors.lastname: Greenwood
authors.affiliation: Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.|Forest Ecology and Restoration Group, Life Sciences Department, Universidad de Alcalá, Science Building, Alcalá de Henares, 28805, Madrid, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Ruiz-Benito
authors.affiliation: CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.|Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Martínez-Vilalta
authors.affiliation: CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.|Universidad Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain.
authors.forename: Francisco
authors.identifier: 0000-0002-9836-4069
authors.initials: F
authors.lastname: Lloret
authors.affiliation: Laboratorio Ecotono, INIBIOMA, CONICET-Universidad Nacional del Comahue, Bariloche, Río Negro, Argentina.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kitzberger
authors.affiliation: U.S. Geological Survey, Fort Collins Science Center, New Mexico Landscapes Field Station, Los Alamos, New Mexico, 87544, USA.
authors.forename: Craig D
authors.initials: CD
authors.lastname: Allen
authors.affiliation: Queensland Herbarium, Environmental Protection Agency, Mt Coot-tha Road, Toowong, Qld, 4066, Australia.|School of Biological Sciences, University of Queensland, St Lucia, Qld, 4072, Australia.
authors.forename: Rod
authors.initials: R
authors.lastname: Fensham
authors.affiliation: Environmental Research Institute and School of Science, University of Waikato, Hamilton, New Zealand.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Laughlin
authors.affiliation: Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany.|German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Deutscher Platz 5e, 04103, Leipzig, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kattge
authors.affiliation: Max Planck Institute for Biogeochemistry, Hans-Knöll-Straße 10, 07745, Jena, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Bönisch
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA.
authors.forename: Nathan J B
authors.initials: NJ
authors.lastname: Kraft
authors.affiliation: Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA, Scotland.|CREAF Cerdanyola del Vallès, Barcelona, 08193, Spain.
authors.forename: Alistair S
authors.initials: AS
authors.lastname: Jump
mesh_terms: D055864:Droughts; D017753:Ecosystem; D008136:Longevity; D018515:Plant Leaves / Q000502:physiology; D014197:Trees / Q000502:physiology*; D014934:Wood / Q000502:physiology
keywords: Climate change; die-off; forest dynamics; functional traits