title: Plant ecology. Worldwide evidence of a unimodal relationship between productivity and plant species richness.
abstract: The search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it. Here, by using data from coordinated surveys conducted throughout grasslands worldwide and comprising a wide range of site productivities, we provide evidence in support of the HBM pattern at both global and regional extents. The relationships described here provide a foundation for further research into the local, landscape, and historical factors that maintain biodiversity.
authors.affiliation: Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, BC, Canada. lfraser@tru.ca.
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authors.initials: LH
authors.lastname: Fraser
authors.affiliation: Department of Biology, University of British Columbia, Okanagan campus, Kelowna, BC, Canada.
authors.forename: Jason
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authors.affiliation: Department of Disturbance Ecology, BayCEER, Uni- versity of Bayreuth, Bayreuth, Germany.
authors.forename: Anke
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authors.lastname: Jentsch
authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel-Aviv, Israel.
authors.forename: Marcelo
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authors.lastname: Sternberg
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
authors.forename: Martin
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authors.affiliation: Faculty of Natural Resources College of Agriculture and Natural Resources, University of Tehran, Iran.
authors.forename: Diana
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authors.affiliation: MTA Centre for Ecological Research, Institute of Ecology and Botany, Vácrátót, Hungary, and School of Plant Biology, University of Western Australia, Crawley, Australia.
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authors.lastname: Bartha
authors.affiliation: Department of Biogeography, BayCEER, University of Bayreuth, Bayreuth, Germany.
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authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Bennett
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Kansas, Manhattan, KS 66047, USA.
authors.forename: Alex
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authors.affiliation: Department of Biology, National University of Mongolia, Ulaanbaatar, Mongolia.
authors.forename: Bazartseren
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authors.affiliation: Department of Botany, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Ilsi I
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authors.affiliation: Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada.
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authors.affiliation: Applied Behavioural Ecology and Ecosystem Research Unit, University of South Africa, Johannesberg, South Africa.
authors.forename: Leslie
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authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (IMBIV-CONICET) and Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, España.
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authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
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authors.affiliation: Department of Agricultural, Food and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada.
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authors.forename: Giandiego
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authors.affiliation: School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy.
authors.forename: Stefano
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authors.affiliation: Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel-Aviv, Israel.
authors.forename: Ofer
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authors.affiliation: School of Natural Sciences, Trinity College Dublin, Dublin, Ireland.
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authors.lastname: Csergo
authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (IMBIV-CONICET) and Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, España.
authors.forename: Sandra
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authors.lastname: Díaz
authors.affiliation: Instituto Multidisciplinario de Biología Vegetal (IMBIV-CONICET) and Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, España.
authors.forename: Lucas
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authors.affiliation: Department of Biology, University of British Columbia, Okanagan campus, Kelowna, BC, Canada.
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authors.forename: Jason D
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authors.lastname: Fridley
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Kansas, Manhattan, KS 66047, USA.
authors.forename: Bryan
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authors.affiliation: Department of Biology, University of Akron, Akron, OH 44325, USA.
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authors.lastname: Garris
authors.affiliation: Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA.
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authors.initials: JR
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authors.affiliation: Department of Biology, University of Western Ontario, London, ON, Canada.
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authors.affiliation: Department of Botany, Corvinus University of Budapest, Budapest, Hungary.
authors.forename: Maria
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authors.affiliation: Department of Natural Resources, Islamic Azad University, Nour Branch, Iran.
authors.forename: Mohammad Hassan
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authors.affiliation: Department of Biology, University of British Columbia, Okanagan campus, Kelowna, BC, Canada.
authors.forename: John
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authors.lastname: Klironomos
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
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authors.affiliation: Department of Botany, University of Otago, Dunedin, New Zealand.
authors.forename: Rachael
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authors.affiliation: International Centre for Tibetan Plateau Ecosystem Management, Lanzhou University, Lanzhou, China.
authors.forename: Ruijun
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authors.affiliation: Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013, Bern, Switzerland.
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authors.affiliation: Department of Biology, University of Akron, Akron, OH 44325, USA.
authors.forename: Randall
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authors.affiliation: Department of Ecology and Evolutionary Biology, University of Kansas, Manhattan, KS 66047, USA.
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authors.affiliation: Department of Ecology and Evolutionary Biology, University of Kansas, Manhattan, KS 66047, USA.
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authors.affiliation: Department of Ecology and Evolutionary Biology, University of Kansas, Manhattan, KS 66047, USA.
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authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
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authors.forename: Szilárd
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authors.forename: Radnaakhand
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authors.forename: Sainbileg
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authors.affiliation: Department of Plant Science, University of Pretoria, Pretoria, South Africa.
authors.forename: Margaretha
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authors.affiliation: Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy.
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mesh_terms: D044822:Biodiversity; D018533:Biomass; D065948:Grassland; D063245:Plant Development; D013312:Stress, Physiological