Stand age and species richness dampen interannual variation of ecosystem-level photosynthetic capacity

Musavi Talie, Migliavacca Mirco, Reichstein Markus, Kattge Jens, Wirth Christian, Black Andrew, Janssens Ivan A., Knohl Alexander, Loustau Denis, Roupsard Olivier, Varlagin Andrej, Rambal Serge, Cescatti Alessandro, Gianelle Damiano, Kondo Hiroaki, Tamrakar Rijan, Mahecha Miguel D.. 2017. Stand age and species richness dampen interannual variation of ecosystem-level photosynthetic capacity. Nature Ecology and Evolution, 1 (2):0048, 6 p.

Quartile : Q4, Sujet : ECOLOGY / Quartile : Q4, Sujet : EVOLUTIONARY BIOLOGY

Résumé : The total uptake of carbon dioxide by ecosystems via photosynthesis (gross primary productivity, GPP) is the largest flux in the global carbon cycle. A key ecosystem functional property determining GPP is the photosynthetic capacity at light saturation (GPPsat), and its interannual variability (IAV) is propagated to the net land–atmosphere exchange of CO2. Given the importance of understanding the IAV in CO2 fluxes for improving the predictability of the global carbon cycle, we have tested a range of alternative hypotheses to identify potential drivers of the magnitude of IAV in GPPsat in forest ecosystems. Our results show that while the IAV in GPPsat within sites is closely related to air temperature and soil water availability fluctuations, the magnitude of IAV in GPPsat is related to stand age and biodiversity (R2= 0.55, P< 0.0001). We find that the IAV of GPPsat is greatly reduced in older and more diverse forests, and is higher in younger forests with few dominant species. Older and more diverse forests seem to dampen the effect of climate variability on the carbon cycle irrespective of forest type. Preserving old forests and their diversity would therefore be beneficial in reducing the effect of climate variability on Earth's forest ecosystems.

Mots-clés Agrovoc : forêt, forêt tropicale, écosystème forestier, cycle du carbone, séquestration du carbone, photosynthèse, composition botanique, biodiversité, compétition végétale, changement climatique, température de l'air, eau du sol, âge, peuplement forestier, réduction des émissions, protection de la forêt

Classification Agris : K01 - Foresterie - Considérations générales
F60 - Physiologie et biochimie végétale
F40 - Écologie végétale
P01 - Conservation de la nature et ressources foncières
P40 - Météorologie et climatologie

Champ stratégique Cirad : Axe 6 (2014-2018) - Sociétés, natures et territoires

Auteurs et affiliations

• Musavi Talie, Max Planck Institut für Biogeochemie (DEU)
• Migliavacca Mirco, Max Planck Institut für Biogeochemie (DEU)
• Reichstein Markus, Max Planck Institut für Biogeochemie (DEU)
• Kattge Jens, Max Planck Institut für Biogeochemie (DEU)
• Wirth Christian, University of Leipzig (DEU)
• Black Andrew, University of British Columbia (CAN)
• Janssens Ivan A., University of Antwerp (BEL)
• Knohl Alexander, Georg-August University of Göttingen (DEU)
• Loustau Denis, INRA (FRA)
• Roupsard Olivier, CIRAD-PERSYST-UMR Eco&Sols (CRI)
• Varlagin Andrej, Russian Academy of Sciences (RUS)
• Rambal Serge, CEFE (FRA)
• Cescatti Alessandro, IES (ITA)
• Gianelle Damiano, FMACH (ITA)
• Kondo Hiroaki, National Institute of Advanced Industrial Science and Technology (JPN)
• Tamrakar Rijan, Georg-August University of Göttingen (DEU)
• Mahecha Miguel D., Max Planck Institut für Biogeochemie (DEU)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/583329/)

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