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| Titel |
Drought-associated changes in climate and their relevance for ecosystem experiments and models |
| VerfasserIn |
H. J. Boeck, H. Verbeeck |
| 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 ; 8, no. 5 ; Nr. 8, no. 5 (2011-05-13), S.1121-1130 |
| Datensatznummer |
250005810
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| Publikation (Nr.) |
 copernicus.org/bg-8-1121-2011.pdf |
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| Zusammenfassung |
| Drought periods can have important impacts on plant productivity and
ecosystem functioning, but climatic conditions other than the lack of
precipitation during droughts have never been quantified and have therefore
not been considered explicitly in both experimental and modeling studies.
Here, we identify which climatic characteristics deviate from normal during
droughts and how these deviations could affect plant responses. Analysis of
609 years of daily data from nine Western European meteorological stations
reveals that droughts in the studied region are consistently associated with
more sunshine (+45 %), increased mean (+1.6 °C) and maximum
(+2.8 °C) air temperatures and vapour pressure deficits that were 51 % higher
than under normal conditions. These deviations from normal increase
significantly as droughts progress. Using the process-model ORCHIDEE, we
simulated droughts consistent with the results of the dataset analysis and
compared water and carbon exchange of three different vegetation types
during such natural droughts and droughts in which only the precipitation
was affected. The comparison revealed contrasting responses: carbon loss was
higher under natural drought in grasslands, while increased carbon uptake
was found especially in decidious forests. This difference was attributed to
better access to water reserves in forest ecosystems which prevented drought
stress. This demonstrates that the warmer and sunnier conditions naturally
associated with droughts can either improve growth or aggravate
drought-related stress, depending on water reserves. As the impacts of
including or excluding climatic parameters that correlate with drought are
substantial, we propose that both experimental and modeling efforts should
take into account other environmental factors than merely precipitation. |
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