Elevated CO2 does not increase eucalypt forest productivity on a low-phosphorus soil

Autor: Andrew N. Gherlenda, Peter B. Reich, Kristine Y. Crous, David S. Ellsworth, Teresa E. Gimeno, Catriona A. Macdonald, John E. Drake, Mark G. Tjoelker, Julia Cooke, Jeff R. Powell, Ian C. Anderson, Belinda E. Medlyn
Přispěvatelé: Hawkesbury Institute for the Environment [Richmond] (HIE), Western Sydney University (UWS), School of Environment, Earth and Ecosystem Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), Interactions Sol Plante Atmosphère (ISPA), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro), Department of Forest Resources, University of Minnesota [Twin Cities], University of Minnesota System-University of Minnesota System, Western Sydney University, Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Interactions Sol Plante Atmosphère (UMR ISPA), University of Minnesota [Twin Cities] (UMN)
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Nature Climate Change
Nature Climate Change, Nature Publishing Group, 2017, 7 (4), pp.279-282. ⟨10.1038/nclimate3235⟩
ISSN: 1758-6798
1758-678X
DOI: 10.1038/nclimate3235⟩
Popis: Experimental evidence from a mature, phosphorous-limited, eucalypt forest finds that aboveground productivity was not significantly stimulated by elevated CO2. Findings suggest that this effect may be limited across much of the tropics. Rising atmospheric CO2 stimulates photosynthesis and productivity of forests, offsetting CO2 emissions1,2. Elevated CO2 experiments in temperate planted forests yielded ∼23% increases in productivity3 over the initial years. Whether similar CO2 stimulation occurs in mature evergreen broadleaved forests on low-phosphorus (P) soils is unknown, largely due to lack of experimental evidence4. This knowledge gap creates major uncertainties in future climate projections5,6 as a large part of the tropics is P-limited. Here, we increased atmospheric CO2 concentration in a mature broadleaved evergreen eucalypt forest for three years, in the first large-scale experiment on a P-limited site. We show that tree growth and other aboveground productivity components did not significantly increase in response to elevated CO2 in three years, despite a sustained 19% increase in leaf photosynthesis. Moreover, tree growth in ambient CO2 was strongly P-limited and increased by ∼35% with added phosphorus. The findings suggest that P availability may potentially constrain CO2-enhanced productivity in P-limited forests; hence, future atmospheric CO2 trajectories may be higher than predicted by some models. As a result, coupled climate–carbon models should incorporate both nitrogen and phosphorus limitations to vegetation productivity7 in estimating future carbon sinks.
Databáze: OpenAIRE
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