Interactions among nutrients govern the global grassland biomass–precipitation relationship
Abstract
Ecosystems are experiencing changing global patterns of mean annual precipitation (MAP) and enrichment with multiple nutrients that potentially colimit plant biomass production. In grasslands, mean aboveground plant biomass is closely related to MAP, but how this relationship changes after enrichment with multiple nutrients remains unclear. We hypothesized the global biomass–MAP relationship becomes steeper with an increasing number of added nutrients, with increases in steepness corresponding to the form of interaction among added nutrients and with increased mediation by changes in plant community diversity. We measured aboveground plant biomass production and species diversity in 71 grasslands on six continents representing the global span of grassland MAP, diversity, management, and soils. We fertilized all sites with nitrogen, phosphorus, and potassium with micronutrients in all combinations to identify which nutrients limited biomass at each site. As hypothesized, fertilizing with one, two, or three nutrients progressively steepened the global biomass–MAP relationship. The magnitude of the increase in steepness corresponded to whether sites were not limited by nitrogen or phosphorus, were limited by either one, or were colimited by both in additive, or synergistic forms. Unexpectedly, we found only weak evidence for mediation of biomass–MAP relationships by plant community diversity because relationships of species richness, evenness, and beta diversity to MAP and to biomass were weak or opposing. Site-level properties including baseline biomass production, soils, and management explained little variation in biomass–MAP relationships. These findings reveal multiple nutrient colimitation as a defining feature of the global grassland biomass–MAP relationship.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (51)
Philip A. Fay
United States Department of Agriculture, Agricultural Research Service, Grassland, Soil, and Water Lab
Laureano A. Gherardi
Department of Environmental Sciences, Policy, and Management, University of California
Laura Yahdjian
Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura-Consejo Nacional de Investigaciones Científicas y Técnicas, Cátedra de Ecología, Facultad de Agronomía, Universidad de Buenos Aires
Peter B. Adler
Department of Wildland Resources and the Ecology Center, Utah State University
Jonathan D. Bakker
School of Environmental and Forest Sciences, University of Washington
Siddharth Bharath
Department of Ecology, Evolution, and Behavior, University of Minnesota
Elizabeth T. Borer
Department of Ecology, Evolution, and Behavior, University of Minnesota
W. Stanley Harpole
German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig
Erika Hersch-Green
Department of Biological Sciences, Michigan Technological University
Travis E. Huxman
Department of Ecology and Evolutionary Biology, University of California
Andrew S. MacDougall
Department of Integrative Biology, University of Guelph
Anita C. Risch
Swiss Federal Institute for Forest, Snow and Landscape Research WSL
Eric W. Seabloom
Department of Ecology, Evolution, and Behavior, University of Minnesota
Sumanta Bagchi
Centre for Ecological Sciences, Indian Institute of Science
Isabel C. Barrio
Faculty of Environmental and Forest Sciences, Agricultural University of Iceland
Lori Biederman
Department of Ecology, Evolution, and Organismal Biology, Iowa State University
Yvonne M. Buckley
Co-Centre for Climate + Biodiversity + Water, School of Natural Sciences, Trinity College Dublin
Miguel N. Bugalho
Center for Applied Ecology “Prof. Baeta Neves”-Research Network in Biodiversity and Evolutionary Biology, School of Agriculture, University of Lisbon
Maria C. Caldeira
Forest Research Centre, Associate Laboratory TERRA, School of Agriculture, University of Lisbon
Jane A. Catford
Department of Geography, King’s College London
Qingqing Chen
Elsa E. Cleland
Ecology, Behavior & Evolution Department, University of California San Diego
Scott L. Collins
Pedro Daleo
Instituto de Investigaciones Marinas y Costeras, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata-Consejo Nacional de Investigaciones Científicas y Técnicas
Christopher R. Dickman
Desert Ecology Research Group, School of Life and Environmental Sciences, The University of Sydney
Ian Donohue
Zoology, School of Natural Sciences, Trinity College Dublin
Mary E. DuPre
MPG Ranch
Nico Eisenhauer
Anu Eskelinen
Nicole Hagenah
Yann Hautier
Robert W. Heckman
Department of Biology, University of North Carolina
Ingibjörg S. Jónsdóttir
Johannes M. H. Knops
Department of Health and Environmental Sciences, Xi’an Jiaotong-Liverpool University
Ramesh Laungani
Department of Environmental Science and Policy, Marist College
Jason P. Martina
Department of Biology, Texas State University
Rebecca L. McCulley
Department of Plant and Soil Sciences, University of Kentucky
John W. Morgan
Department of Environment and Genetics, La Trobe University
Harry Olde Venterink
Department of Biology-Wildness, Biodiversity, and Ecosystems Under Change, Vrije Universiteit Brussel
Pablo L. Peri
Sally A. Power
Hawkesbury Institute for the Environment, Western Sydney University
Xavier Raynaud
Sorbonne Université, Université de Paris- Cité, Université Paris-Est Créteil, Institut de Recherche pour le Développement, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Institut d'Ecologie et des Sciences de l'Envrionnement de Paris
Zhengwei Ren
College of Ecology, Lanzhou University
Christiane Roscher
German Centre for Integrative Biodiversity Research, Halle-Jena-Leipzig
Melinda D. Smith
Marie Spohn
Department of Soil and Environment, Swedish University of Agricultural Sciences
Carly J. Stevens
Lancaster Environment Centre, Lancaster University
Michelle J. Tedder
Centre for Functional Biodiversity, School of Life Sciences, University of KwaZulu-Natal
Risto Virtanen
Glenda M. Wardle
School of Life and Environmental Sciences, ARC Training Centre in Data Analytics for Resources and Environments, The University of Sydney
George R. Wheeler
Department of Biological Sciences, Michigan Technological University