Asymmetric responses of primary productivity to precipitation extremes: A synthesis of grassland precipitation manipulation experiments.
Kevin R Wilcox, Zheng Shi, Laureano A Gherardi, Nathan P Lemoine, Sally E Koerner, David L Hoover, Edward Bork, Kerry M Byrne, James Cahill, Scott L Collins, Sarah Evans, Anna K Gilgen, Petr Holub, Lifen Jiang, Alan K Knapp, Daniel LeCain, Junyi Liang, Pablo Garcia-Palacios, Josep Peñuelas, William T Pockman, Melinda D Smith, Shanghua Sun, Shannon R White, Laura Yahdjian, Kai Zhu, Yiqi Luo
Author Information
Kevin R Wilcox: Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA. ORCID
Zheng Shi: Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
Laureano A Gherardi: School of Life Sciences, Arizona State University, Tempe, AZ, USA.
Nathan P Lemoine: Department of Biology & Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA.
Sally E Koerner: Department of Integrative Biology, University of South Florida, Tampa, FL, USA.
David L Hoover: U.S. Department of Agriculture, Agriculture Research Service, Fort Collins, CO, USA.
Edward Bork: Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, AB, Canada.
Kerry M Byrne: Department of Environmental Science and Management, Humboldt State University, Arcata, CA, USA.
James Cahill: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
Scott L Collins: Department of Biology, University of New Mexico, Albuquerque, NM, USA.
Sarah Evans: Department of Integrative Biology, Department of Microbiology and Molecular Genetics and Kellogg Biological Station, Michigan State University, Hickory Corners, MI, USA.
Anna K Gilgen: Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland.
Petr Holub: Global Change Research Institute, Czech Academy of Sciences, Brno, Czech Republic.
Lifen Jiang: Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA. ORCID
Alan K Knapp: Department of Biology & Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA.
Daniel LeCain: U.S. Department of Agriculture, Agriculture Research Service, Fort Collins, CO, USA.
Junyi Liang: Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
Pablo Garcia-Palacios: Área de Biodiversidad y Conservación, Departamento de Biología, Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Móstoles, Spain.
Josep Peñuelas: CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain.
William T Pockman: Department of Biology, University of New Mexico, Albuquerque, NM, USA.
Melinda D Smith: Department of Biology & Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA.
Shanghua Sun: College of Forestry, Northwest A & F University, Yangling, China.
Shannon R White: Environment and Parks, Government of Alberta, Edmonton, AB, Canada.
Laura Yahdjian: Facultad de Agronomía, Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, Buenos Aires, Argentina.
Kai Zhu: Department of BioSciences, Rice University, Houston, TX, USA. ORCID
Yiqi Luo: Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
Climatic changes are altering Earth's hydrological cycle, resulting in altered precipitation amounts, increased interannual variability of precipitation, and more frequent extreme precipitation events. These trends will likely continue into the future, having substantial impacts on net primary productivity (NPP) and associated ecosystem services such as food production and carbon sequestration. Frequently, experimental manipulations of precipitation have linked altered precipitation regimes to changes in NPP. Yet, findings have been diverse and substantial uncertainty still surrounds generalities describing patterns of ecosystem sensitivity to altered precipitation. Additionally, we do not know whether previously observed correlations between NPP and precipitation remain accurate when precipitation changes become extreme. We synthesized results from 83 case studies of experimental precipitation manipulations in grasslands worldwide. We used meta-analytical techniques to search for generalities and asymmetries of aboveground NPP (ANPP) and belowground NPP (BNPP) responses to both the direction and magnitude of precipitation change. Sensitivity (i.e., productivity response standardized by the amount of precipitation change) of BNPP was similar under precipitation additions and reductions, but ANPP was more sensitive to precipitation additions than reductions; this was especially evident in drier ecosystems. Additionally, overall relationships between the magnitude of productivity responses and the magnitude of precipitation change were saturating in form. The saturating form of this relationship was likely driven by ANPP responses to very extreme precipitation increases, although there were limited studies imposing extreme precipitation change, and there was considerable variation among experiments. This highlights the importance of incorporating gradients of manipulations, ranging from extreme drought to extreme precipitation increases into future climate change experiments. Additionally, policy and land management decisions related to global change scenarios should consider how ANPP and BNPP responses may differ, and that ecosystem responses to extreme events might not be predicted from relationships found under moderate environmental changes.
