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| Titel |
Can current moisture responses predict soil CO2 efflux under altered precipitation regimes? A synthesis of manipulation experiments |
| VerfasserIn |
S. Vicca, M. Bahn, M. Estiarte, E. E. van Loon, R. Vargas, G. Alberti, P. Ambus, M. A. Arain, C. Beier, L. P. Bentley, W. Borken, N. Buchmann, S. L. Collins, G. de Dato, J. S. Dukes, C. Escolar, P. Fay, G. Guidolotti, P. J. Hanson, A. Kahmen, G. Kröel-Dulay, T. Ladreiter-Knauss, K. S. Larsen, E. Lellei-Kovacs, E. Lebrija-Trejos, F. T. Maestre, S. Marhan, M. Marshall, P. Meir, Y. Miao, J. Muhr, P. A. Niklaus, R. Ogaya, J. Peñuelas, C. Poll, L. E. Rustad, K. Savage, A. Schindlbacher, I. K. Schmidt, A. R. Smith, E. D. Sotta, V. Suseela, A. Tietema, N. van Gestel, O. van Straaten, S. Wan, U. Weber, I. A. Janssens |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 11 ; Nr. 11, no. 11 (2014-06-06), S.2991-3013 |
| Datensatznummer |
250117449
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| Publikation (Nr.) |
 copernicus.org/bg-11-2991-2014.pdf |
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| Zusammenfassung |
| As a key component of the carbon cycle, soil CO2 efflux (SCE) is being
increasingly studied to improve our mechanistic understanding of this
important carbon flux. Predicting ecosystem responses to climate change
often depends on extrapolation of current relationships between ecosystem
processes and their climatic drivers to conditions not yet experienced by
the ecosystem. This raises the question of to what extent these relationships
remain unaltered beyond the current climatic window for which observations
are available to constrain the relationships. Here, we evaluate whether
current responses of SCE to fluctuations in soil temperature and soil water
content can be used to predict SCE under altered rainfall patterns. Of the
58 experiments for which we gathered SCE data, 20 were discarded because
either too few data were available or inconsistencies precluded their
incorporation in the analyses. The 38 remaining experiments were used to
test the hypothesis that a model parameterized with data from the control
plots (using soil temperature and water content as predictor variables)
could adequately predict SCE measured in the manipulated treatment. Only for
7 of these 38 experiments was this hypothesis rejected. Importantly,
these were the experiments with the most reliable data sets, i.e., those
providing high-frequency measurements of SCE. Regression tree analysis
demonstrated that our hypothesis could be rejected only for experiments with
measurement intervals of less than 11 days, and was not rejected for any of
the 24 experiments with larger measurement intervals. This highlights the
importance of high-frequency measurements when studying effects of altered
precipitation on SCE, probably because infrequent measurement schemes have
insufficient capacity to detect shifts in the climate dependencies of SCE.
Hence, the most justified answer to the question of whether current moisture
responses of SCE can be extrapolated to predict SCE under altered
precipitation regimes is "no" – as based on the most reliable data sets
available. We strongly recommend that future experiments focus more strongly
on establishing response functions across a broader range of precipitation
regimes and soil moisture conditions. Such experiments should make accurate
measurements of water availability, should conduct high-frequency SCE
measurements, and should consider both instantaneous responses and the
potential legacy effects of climate extremes. This is important, because
with the novel approach presented here, we demonstrated that, at least for
some ecosystems, current moisture responses could not be extrapolated to
predict SCE under altered rainfall conditions. |
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