title: Increasing aridity reduces soil microbial diversity and abundance in global drylands.
abstract: Soil bacteria and fungi play key roles in the functioning of terrestrial ecosystems, yet our understanding of their responses to climate change lags significantly behind that of other organisms. This gap in our understanding is particularly true for drylands, which occupy ∼41% of Earth´s surface, because no global, systematic assessments of the joint diversity of soil bacteria and fungi have been conducted in these environments to date. Here we present results from a study conducted across 80 dryland sites from all continents, except Antarctica, to assess how changes in aridity affect the composition, abundance, and diversity of soil bacteria and fungi. The diversity and abundance of soil bacteria and fungi was reduced as aridity increased. These results were largely driven by the negative impacts of aridity on soil organic carbon content, which positively affected the abundance and diversity of both bacteria and fungi. Aridity promoted shifts in the composition of soil bacteria, with increases in the relative abundance of Chloroflexi and α-Proteobacteria and decreases in Acidobacteria and Verrucomicrobia. Contrary to what has been reported by previous continental and global-scale studies, soil pH was not a major driver of bacterial diversity, and fungal communities were dominated by Ascomycota. Our results fill a critical gap in our understanding of soil microbial communities in terrestrial ecosystems. They suggest that changes in aridity, such as those predicted by climate-change models, may reduce microbial abundance and diversity, a response that will likely impact the provision of key ecosystem services by global drylands.
authors.affiliation: Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Móstoles, Spain; fernando.maestre@urjc.es.
authors.forename: Fernando T
authors.identifier: 0000-0002-7434-4856
authors.initials: FT
authors.lastname: Maestre
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Penrith, 2751, NSW, Australia;
authors.forename: Manuel
authors.initials: M
authors.lastname: Delgado-Baquerizo
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Penrith, 2751, NSW, Australia;
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Jeffries
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia;
authors.forename: David J
authors.initials: DJ
authors.lastname: Eldridge
authors.affiliation: Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Móstoles, Spain;
authors.forename: Victoria
authors.initials: V
authors.lastname: Ochoa
authors.affiliation: Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, 28933 Móstoles, Spain;
authors.forename: Beatriz
authors.initials: B
authors.lastname: Gozalo
authors.affiliation: Departamento de Ingeniería Forestal, Escuela Técnica Superior de Ingeniería Agronómica y de Montes, Universidad de Córdoba, Campus de Rabanales, C.P. 14071, Córdoba, Spain;
authors.forename: José Luis
authors.initials: JL
authors.lastname: Quero
authors.affiliation: Departamento de Ingeniería y Morfología del Terreno, Escuela Técnica Superior de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, 28040 Madrid, Spain;
authors.forename: Miguel
authors.initials: M
authors.lastname: García-Gómez
authors.affiliation: Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, 41013 Sevilla, Spain;
authors.forename: Antonio
authors.initials: A
authors.lastname: Gallardo
authors.affiliation: Chair of Ecology and Biogeography, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland;
authors.forename: Werner
authors.initials: W
authors.lastname: Ulrich
authors.affiliation: School of Forestry, Northern Arizona University, Flagstaff, AZ 86011;
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Bowker
authors.affiliation: Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, San Luis Potosí, SLP, México;
authors.forename: Tulio
authors.initials: T
authors.lastname: Arredondo
authors.affiliation: Departamento de Biología, Facultad de Ciencias, Universidad de La Serena, Benavente 980, Casilla 554, La Serena, Chile;
authors.forename: Claudia
authors.initials: C
authors.lastname: Barraza-Zepeda
authors.affiliation: Nacional de Tecnología Agropecuaria, Estación Experimental San Carlos de Bariloche, San Carlos de Bariloche, Río Negro, Argentina;
authors.forename: Donaldo
authors.initials: D
authors.lastname: Bran
authors.affiliation: Instituto de Edafología, Facultad de Agronomía, Universidad Central de Venezuela, Campus UCV-Maracay, ZP 2101, Estado Aragua, Venezuela;
authors.forename: Adriana
authors.initials: A
authors.lastname: Florentino
authors.affiliation: Instituto de Suelos, Centro de Investigación en Recursos Naturales, Instituto Nacional de Tecnología Agropecuaria, Nicolas Repetto y de los Reseros Sin Número, 1686 Hurlingham, Buenos Aires, Argentina;
authors.forename: Juan
authors.initials: J
authors.lastname: Gaitán
authors.affiliation: Departamento de Biología, Facultad de Ciencias, Universidad de La Serena, Benavente 980, Casilla 554, La Serena, Chile; Centro de Estudios Avanzados en Zonas Áridas (CEAZA), La Serena, Chile; Instituto de Ecología y Biodiversidad, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653, Ñuñoa, Santiago, Chile;
authors.forename: Julio R
authors.initials: JR
authors.lastname: Gutiérrez
authors.affiliation: Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, San Luis Potosí, SLP, México;
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Huber-Sannwald
authors.affiliation: Department of Range and Watershed Management, Ferdowsi University of Mashhad, Mashhad, 91775-1363, Iran;
authors.forename: Mohammad
authors.initials: M
authors.lastname: Jankju
authors.affiliation: Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011;
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Mau
authors.affiliation: Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH 43210;
authors.forename: Maria
authors.initials: M
authors.lastname: Miriti
authors.affiliation: Department of Range and Watershed Management, Ferdowsi University of Mashhad, Mashhad, 91775-1363, Iran;
authors.forename: Kamal
authors.initials: K
authors.lastname: Naseri
authors.affiliation: Instituto de Edafología, Facultad de Agronomía, Universidad Central de Venezuela, Campus UCV-Maracay, ZP 2101, Estado Aragua, Venezuela;
authors.forename: Abelardo
authors.initials: A
authors.lastname: Ospina
authors.affiliation: Dead Sea and Arava Science Center, Yotvata 88840, Israel;
authors.forename: Ilan
authors.initials: I
authors.lastname: Stavi
authors.affiliation: Institute of Grassland Science, Key Laboratory for Vegetation Ecology, Northeast Normal University, Changchun, Jilin 130024, China;
authors.forename: Deli
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH 43210;
authors.forename: Natasha N
authors.initials: NN
authors.lastname: Woods
authors.affiliation: Institute of Grassland Science, Key Laboratory for Vegetation Ecology, Northeast Normal University, Changchun, Jilin 130024, China;
authors.forename: Xia
authors.initials: X
authors.lastname: Yuan
authors.affiliation: Department of Natural Resources, Agriculture Research Organization, Ministry of Agriculture, Gilat Research Center, Mobile Post Negev 85280, Israel;
authors.forename: Eli
authors.initials: E
authors.lastname: Zaady
authors.affiliation: Hawkesbury Institute for the Environment, Western Sydney University, Penrith, 2751, NSW, Australia; Global Centre for Land-Based Innovation, Western Sydney University, Penrith, 2751, NSW, Australia.
authors.forename: Brajesh K
authors.initials: BK
authors.lastname: Singh
mesh_terms: D057231:Climate Change; D017753:Ecosystem; D006863:Hydrogen-Ion Concentration; D012988:Soil Microbiology
keywords: arid; bacteria; climate change; fungi; semiarid