Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements

• Published in: Rangeland ecology & management 2010-01, Vol.63 (1), p.16-39
• Main Authors: Gilmanov, Tagir G., Aires, L., Barcza, Z., Baron, V. S., Belelli, L., Beringer, J., Billesbach, D., Bonal, D., Bradford, J., Ceschia, E., Cook, D., Corradi, C., Frank, A., Gianelle, D., Gimeno, C., Gruenwald, T., Guo, Haiqiang, Hanan, N., Haszpra, L., Heilman, J., Jacobs, A., Jones, M. B., Johnson, D. A., Kiely, G., Li, Shenggong, Magliulo, V., Moors, E., Nagy, Z., Nasyrov, M., Owensby, C., Pinter, K., Pio, C., Reichstein, M., Sanz, M. J., Scott, R., Soussana, J. F., Stoy, P. C., Svejcar, T., Tuba, Z., Zhou, Guangsheng
• Format: Article
• Language: English
• Subjects: agro-ecosystemen; Agroecosystems; biogeochemical cycles; Carbon; carbon cycle; Carbon dioxide; carbon-dioxide exchange; cell respiration; Climatology; co2 exchange; Colleges & universities; Comparative analysis; crop yield; croplands; crops; Ecosystem management; ecosystem respiration; Ecosystems; eddy covariance; ENVIRONMENTAL SCIENCES; Forest ecosystems; forests; gas exchange; geographical variation; graslanden; Grasses; Grasslands; gross primary production; gross primary productivity; Klimatologie; kooldioxide; koolstofcyclus; Life Sciences; light intensity; light-response function method; measurement; Methods; meting; net CO2 flux partitioning; net ecosystem carbon balance; net ecosystem CO2 exchange; Net ecosystem exchange; netto ecosysteem koolstofbalans; northern great-plains; photosynthesis; Primary productivity; Productivity; radiation use efficiency; range management; rangelands; Research Papers; Respiration; savannas; shrublands; soil; solar radiation; Special Issue: Global Grazinglands and Greenhouse Gas Fluxes: Guest Editors—Emilio A. Laca, Mary-Brooke McEachern, and Montague W. Demment; tallgrass prairie; temperate grassland; Terrestrial ecosystems; tropical forests; water-vapor
• ISSN: 1550-7424; 1551-5028; 1551-5028
• DOI: 10.2111/REM-D-09-00072.1

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 CO2 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 CO2 fluxes in a sagebrush-steppe 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. Grünwald, K. Havránková, 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 11:1424–1439). Maximum values of the quantum yield (α  =  75 mmol · mol−1), photosynthetic capacity (Amax  =  3.4 mg CO2 · m−2 · s−1), gross photosynthesis (Pg,max  =  116 g CO2 · m−2 · d−1), and ecological light-use efficiency (εecol  =  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 CO2. Maximum values of gross primary production (8 600 g CO2 · m−2 · yr−1), total ecosystem respiration (7 900 g CO2 · m−2 · yr−1), and net CO2 exchange (2 400 g CO2 · 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 CO2, with mean net uptake of 700 g CO2 · m−2 · yr−1 for intensive grasslands and 933 g CO2 · m−2 · d−1 for croplands. However, part of these apparent sinks is accumulated in crop