title: Intransitive competition is widespread in plant communities and maintains their species richness.
abstract: Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity-richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in > 65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation.
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Santiago
authors.initials: S
authors.lastname: Soliveres
authors.affiliation: Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Calle Tulipán S/N, 28933, Móstoles, Spain.
authors.forename: Fernando T
authors.initials: FT
authors.lastname: Maestre
authors.affiliation: Chair of Ecology and Biogeography Nicolaus Copernicus University in Toruń Lwowska1, 87-100, Toruń, Poland.
authors.forename: Werner
authors.initials: W
authors.lastname: Ulrich
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Manning
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Steffen
authors.initials: S
authors.lastname: Boch
authors.affiliation: School of Forestry, Northern Arizona University, 200 East Pine Knoll Drive, 86011, Flagstaff, AZ, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Bowker
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Prati
authors.affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, 2751, New South Wales, Australia.
authors.forename: Manuel
authors.initials: M
authors.lastname: Delgado-Baquerizo
authors.affiliation: Departamento de Ingeniería Forestal, Escuela Técnica Superior de Ingeniería Agronómica y de Montes, Universidad de Córdoba, Edificio Leonardo da Vinci, 1ª planta. Campus de Rabanales, Ctra N-IV km 396. C.P, 14071, Córdoba, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Quero
authors.affiliation: Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Schöning
authors.affiliation: Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera kilómetro 1, 41013, Sevilla, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gallardo
authors.affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management, School of Life Sciences Weihenstephan, Technische Universität München, Hans-Carl-von-Carlowitz-Platz 2, Freising, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weisser
authors.affiliation: Institut für Biochemie und Biologie, Universität Potsdam, Maulbeerallee 1, 14469, Potsdamm, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Müller
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Socher
authors.affiliation: Departamento de Ingeniería y Morfología del Terreno, Escuela Técnica Superior de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, Calle Profesor Aranguren S/N, 28040, Madrid, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: García-Gómez
authors.affiliation: Área de Biodiversidad y Conservación, Departamento de Biología y Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Calle Tulipán S/N, 28933, Móstoles, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Ochoa
authors.affiliation: Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany.
authors.forename: Ernst-Detlef
authors.initials: ED
authors.lastname: Schulze
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, 3013, Bern, Switzerland.
authors.forename: Eric
authors.initials: E
authors.lastname: Allan
mesh_terms: D000383:Agriculture; D044822:Biodiversity; D057231:Climate Change; D005858:Germany; D065948:Grassland; D008954:Models, Biological; D010944:Plants / Q000145:classification*
keywords: Aridity; biodiversity; coexistence; drylands; land use; mesic grasslands; rock-paper-scissors game