How do climate warming and species richness affect CO2 fluxes in experimental grasslands?
Article first published online: 7 JUN 2007
Volume 175, Issue 3, pages 512–522, August 2007
How to Cite
De Boeck, H. J., Lemmens, C. M. H. M., Vicca, S., Van den Berge, J., Van Dongen, S., Janssens, I. A., Ceulemans, R. and Nijs, I. (2007), How do climate warming and species richness affect CO2 fluxes in experimental grasslands?. New Phytologist, 175: 512–522. doi: 10.1111/j.1469-8137.2007.02122.x
- Issue published online: 7 JUN 2007
- Article first published online: 7 JUN 2007
- Received: 15 February 2007 Accepted: 12 April 2007
- carbon balance;
- climate warming;
- CO2 fluxes;
- global change;
- grassland species;
- species richness
- • This paper presents the results of 2 yr of CO2 flux measurements on grassland communities of varying species richness, exposed to either the current or a warmer climate.
- • We grew experimental plant communities containing one, three or nine grassland species in 12 sunlit, climate-controlled chambers. Half of these chambers were exposed to ambient air temperatures, while the other half were warmed by 3°C. Equal amounts of water were added to heated and unheated communities, implying drier soils if warming increased evapotranspiration. Three main CO2 fluxes (gross photosynthesis, above-ground and below-ground respiration) were measured multiple times per year and reconstructed hourly or half-hourly by relating them to their most important environmental driver.
- • While CO2 outputs through respiration were largely unchanged under warming, CO2 inputs through photosynthesis were lowered, especially in summer, when heat and drought stress were higher. Above-ground CO2 fluxes were significantly increased in multispecies communities, as more complementary resource use stimulated productivity. Finally, effects of warming appeared to be smallest in monocultures.
- • This study shows that in a future warmer climate the CO2 sink capacity of temperate grasslands could decline, and that such adverse effects are not likely to be mitigated by efforts to maintain or increase species richness.