title: Grassland productivity limited by multiple nutrients.
abstract: Terrestrial ecosystem productivity is widely accepted to be nutrient limited(1). Although nitrogen (N) is deemed a key determinant of aboveground net primary production (ANPP)(2,3), the prevalence of co-limitation by N and phosphorus (P) is increasingly recognized(4-8). However, the extent to which terrestrial productivity is co-limited by nutrients other than N and P has remained unclear. Here, we report results from a standardized factorial nutrient addition experiment, in which we added N, P and potassium (K) combined with a selection of micronutrients (K+μ), alone or in concert, to 42 grassland sites spanning five continents, and monitored ANPP. Nutrient availability limited productivity at 31 of the 42 grassland sites. And pairwise combinations of N, P, and K+μ co-limited ANPP at 29 of the sites. Nitrogen limitation peaked in cool, high latitude sites. Our findings highlight the importance of less studied nutrients, such as K and micronutrients, for grassland productivity, and point to significant variations in the type and degree of nutrient limitation. We suggest that multiple-nutrient constraints must be considered when assessing the ecosystem-scale consequences of nutrient enrichment.
authors.affiliation: USDA-ARS Grassland Soil and Water Research Lab, Temple, Texas 76502, USA.
authors.forename: Philip A
authors.identifier: http://orcid.org/0000-0002-8291-6316
authors.initials: PA
authors.lastname: Fay
authors.affiliation: CSIRO Land and Water Flagship, Private Bag 5, Wembley, Western Australia 6913, Australia.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Prober
authors.affiliation: Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011, USA.|German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, Leipzig D-04103, Germany.|Department of Physiological Diversity, Helmholtz Center for Environmental Research - UFZ, Permoserstr. 15, Leipzig 04318, Germany.|Institute of Biology, Martin Luther University Halle-Wittenberg, Am Kirchtor 1, Halle (Saale) 06108, Germany.
authors.forename: W Stanley
authors.initials: WS
authors.lastname: Harpole
authors.affiliation: School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA.
authors.forename: Johannes M H
authors.initials: JM
authors.lastname: Knops
authors.affiliation: School of Environmental and Forest Sciences, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Bakker
authors.affiliation: Department of Ecology, Evolution, and Behavior, University of MN, St. Paul, Minnesota 55108, USA.
authors.forename: Elizabeth T
authors.identifier: http://orcid.org/0000-0003-2259-5853
authors.initials: ET
authors.lastname: Borer
authors.affiliation: Department of Ecology, Evolution, and Behavior, University of MN, St. Paul, Minnesota 55108, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Lind
authors.affiliation: Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: MacDougall
authors.affiliation: Department of Ecology, Evolution, and Behavior, University of MN, St. Paul, Minnesota 55108, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Seabloom
authors.affiliation: Department of Ecology, Evolution, and Behavior, University of MN, St. Paul, Minnesota 55108, USA.
authors.forename: Peter D
authors.identifier: http://orcid.org/0000-0003-2361-4286
authors.initials: PD
authors.lastname: Wragg
authors.affiliation: Department of Wildland Resources and the Ecology Center, Utah State University, Logan, Utah 84322, USA.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Adler
authors.affiliation: USDA-ARS Rangeland Resources Research Unit, Fort Collins, Colorado 80526, USA.
authors.forename: Dana M
authors.initials: DM
authors.lastname: Blumenthal
authors.affiliation: School of Natural Sciences, Zoology, Trinity Centre for Biodiversity Research, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Yvonne M
authors.identifier: http://orcid.org/0000-0001-7599-3201
authors.initials: YM
authors.lastname: Buckley
authors.affiliation: Research Station of Alpine Meadow and Wetland Ecosystems, Lanzhou University, Lanzhou 730000, China.
authors.forename: Chengjin
authors.initials: C
authors.lastname: Chu
authors.affiliation: Ecology, Behavior &Evolution Section, University of California, La Jolla, San Diego, California 92093, USA.
authors.forename: Elsa E
authors.initials: EE
authors.lastname: Cleland
authors.affiliation: Department of Biology, MSC03-2020, University of New Mexico, Albuquerque, New Mexico 88003, USA.
authors.forename: Scott L
authors.initials: SL
authors.lastname: Collins
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Kendi F
authors.initials: KF
authors.lastname: Davies
authors.affiliation: Research Station of Alpine Meadow and Wetland Ecosystems, Lanzhou University, Lanzhou 730000, China.
authors.forename: Guozhen
authors.initials: G
authors.lastname: Du
authors.affiliation: Department of Plant Biology, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Feng
authors.affiliation: School of Earth, Environment and Biological Sciences, Queensland University of Technology, Brisbane, Queensland 4001, Australia.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Firn
authors.affiliation: Department of Entomology, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Daniel S
authors.identifier: http://orcid.org/0000-0002-3153-4297
authors.initials: DS
authors.lastname: Gruner
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg 3209, South Africa.
authors.forename: Nicole
authors.initials: N
authors.lastname: Hagenah
authors.affiliation: Ecology and Biodiversity Group, Department of Biology, Utrecht University, Padualaan 8, Utrecht, CH 3584, Netherlands.
authors.forename: Yann
authors.initials: Y
authors.lastname: Hautier
authors.affiliation: Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Heckman
authors.affiliation: USDA-ARS Agroecosystem Management Research Unit, Lincoln, Nebraska 68538, USA.
authors.forename: Virginia L
authors.initials: VL
authors.lastname: Jin
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg 3209, South Africa.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Kirkman
authors.affiliation: Department of Forest, Rangeland, and Watershed Stewardship, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Klein
authors.affiliation: Department of Biology, MSC03-2020, University of New Mexico, Albuquerque, New Mexico 88003, USA.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Ladwig
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: McCulley
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Brett A
authors.initials: BA
authors.lastname: Melbourne
authors.affiliation: Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Mitchell
authors.affiliation: School of Biological Sciences, Monash University, Victoria 3800, Australia.
authors.forename: Joslin L
authors.initials: JL
authors.lastname: Moore
authors.affiliation: Department of Botany, La Trobe University, Bundoora 3083, Victoria, Australia.
authors.forename: John W
authors.initials: JW
authors.lastname: Morgan
authors.affiliation: Swiss Federal Institute for Forest, Snow and Landscape Research, Community Ecology, Birmensdorf 8903, Switzerland.
authors.forename: Anita C
authors.initials: AC
authors.lastname: Risch
authors.affiliation: Swiss Federal Institute for Forest, Snow and Landscape Research, Community Ecology, Birmensdorf 8903, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Schütz
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
authors.forename: Carly J
authors.initials: CJ
authors.lastname: Stevens
authors.affiliation: School of Natural Resources, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Wedin
authors.affiliation: Department of Entomology and Nematology, University of California, Davis, California 95616, USA.
authors.forename: Louie H
authors.identifier: http://orcid.org/0000-0002-9237-5357
authors.initials: LH
authors.lastname: Yang