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Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements
Auteur(s) : Gilmanov, Tagir G. Aires, Luis Barcza, Zoltán Baron, V. S. Belelli, Luca Beringer, Jason Billesbach, D. Bonal, Damien
Auteurs secondaires : Department of Biology and Microbiology ; South Dakota State University (SDSTATE) University of Aveiro Department Meteorology [Budapest] ; Institute of Geography and Earth Sciences [Budapest] ; Eötvös Loránd University (ELTE) - Eötvös Loránd University (ELTE) Lacombe Research Centre ; Agriculture and Agri-Food [Ottawa] (AAFC) Tuscia University School of Geography and Environmental Scienc ; Monash University [Clayton] Department of Biological Systems Engineering ; University of Nebraska Ecologie des forêts de Guyane (ECOFOG) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) - Institut National de la Recherche Agronomique (INRA) - Université des Antilles et de la Guyane (UAG) - AgroParisTech - Centre National de la Recherche Scientifique (CNRS)

Éditeur(s) : HAL CCSD Society for Range Management
Résumé : Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO(2) exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands, shrublands/savanna, wetlands, and cropland ecosystems worldwide. We analyzed data from 72 global flux-tower sites partitioned into gross photosynthesis and ecosystem respiration with the use of the light-response method (Gilmanov, T. G., D. A. Johnson, and N. Z. Saliendra. 2003. Growing season CO(2) fluxes in a sagebrushsteppe ecosystem in Idaho: Bowen ratio/energy balance measurements and modeling. Basic and Applied Ecology 4:167-183) from the RANGEFLUX and WORLDGRASSAGRIFLUX data sets supplemented by 46 sites from the FLUXNET La Thuile data set partitioned with the use of the temperature-response method (Reichstein, M., E. Falge, D. Baldocchi, D. Papale, R. Valentini, M. Aubinet, P. Berbigier, C. Bernhofer, N. Buchmann, M. Falk, T. Gilmanov, A. Granier, T. Grunwald, K. Havrankova, D. Janous, A. Knohl, T. Laurela, A. Lohila, D. Loustau, G. Matteucci, T. Meyers, F. Miglietta, J.M. Ourcival, D. Perrin, J. Pumpanen, S. Rambal, E. Rotenberg, M. Sanz, J. Tenhunen, G. Seufert, F. Vaccari, T. Vesala, and D. Yakir. 2005. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology 11: 1.424-1439). Maximum values of the quantum yield (alpha = 75 mmol.mol(-1)), photosynthetic capacity (A(max) = 3.4 mg CO(2) . m(-2).s-1), gross photosynthesis (P(g,max) = 1.16 g CO(2) . m(-2).d(-1)), and ecological light-use efficiency (epsilon(ecol) = 59 mmol . mol(-1)) of managed grasslands and high-production croplands exceeded those of most forest ecosystems, indicating the potential of nonforest ecosystems for uptake of atmospheric CO(2). Maximum values of gross primary production (8 600 g CO(2) . m(-2).yr(-1)), total ecosystem respiration (7 900 g CO(2) . m(-2).yr(-1)), and net CO(2) exchange (2 400 g CO(2) . m(-2).yr(-1)) were observed for intensively managed grasslands and high-yield crops, and are comparable to or higher than those for forest ecosystems, excluding some tropical forests. On average, 80% of the nonforest sites were apparent sinks for atmospheric CO(2), with mean net uptake of 700 g CO(2) . m(-2).yr(-1) for intensive grasslands and 933 g CO(2) . m(-2).d(-1) for croplands. However, part of these apparent sinks is accumulated in crops and forage, which are carbon pools that are harvested, transported, and decomposed off site. Therefore, although agricultural fields may be predominantly sinks for atmospheric CO(2), this does not imply that they are necessarily increasing their carbon stock.
ISSN: 1550-7424

hal-01190754
https://hal.archives-ouvertes.fr/hal-01190754
DOI : 10.2111/rem-d-09-00072.1
PRODINRA : 214043

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CO2 balance of boreal, temperate, and tropical forests derived from a global database
Auteur(s) : Luyssaert, S. INGLIMA, I. Jung, M. RICHARDSON, A. D. Reichstein, M. Papale, D. Piao, S. L. SCHULZE, E. -D.
Auteurs secondaires : Department of Biology ; University of Antwerp (UA) Centre Interdisciplinaire de Recherche Ions Lasers (CIRIL) ; Université de Caen Normandie (UNICAEN) ; Normandie Université (NU) - Normandie Université (NU) - Ecole Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN) ; Normandie Université (NU) - Commissariat à l'énergie atomique et aux énergies alternatives (CEA) - Centre National de la Recherche Scientifique (CNRS) Faculty of Information Sciences and Engineering ; University of Canberra Biogeochemical-Model-Data Integration Group ; Max Planck Institute for Biogeochemistry Department of Forest Environment and Resources ; University of Tuscia Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China ; affiliation inconnue Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China ; affiliation inconnue Max-Planck-Institut für Biogeochemie (MPI-BGC)

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