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| Titel |
Meta-analysis of high-latitude nitrogen-addition and warming studies implies ecological mechanisms overlooked by land models |
| VerfasserIn |
N. J. Bouskill, W. J. Riley, J. Y. Tang |
| 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. 23 ; Nr. 11, no. 23 (2014-12-11), S.6969-6983 |
| Datensatznummer |
250117729
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| Publikation (Nr.) |
 copernicus.org/bg-11-6969-2014.pdf |
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| Zusammenfassung |
| Accurate representation of ecosystem processes in land models is crucial for
reducing predictive uncertainty in energy and greenhouse gas feedbacks with
the climate. Here we describe an observational and modeling meta-analysis
approach to benchmark land models, and apply the method to the land model
CLM4.5 with two versions of belowground biogeochemistry. We focused our
analysis on the aboveground and belowground responses to warming and nitrogen
addition in high-latitude ecosystems, and identified absent or poorly
parameterized mechanisms in CLM4.5. While the two model versions predicted
similar soil carbon stock trajectories following both warming and nitrogen
addition, other predicted variables (e.g., belowground respiration) differed
from observations in both magnitude and direction, indicating that CLM4.5 has
inadequate underlying mechanisms for representing high-latitude ecosystems.
On the basis of observational synthesis, we attribute the model–observation
differences to missing representations of microbial dynamics, aboveground and
belowground coupling, and nutrient cycling, and we use the observational
meta-analysis to discuss potential approaches to improving the current
models. However, we also urge caution concerning the selection of data sets
and experiments for meta-analysis. For example, the concentrations of
nitrogen applied in the synthesized field experiments
(average = 72 kg ha−1 yr−1) are many times higher than
projected soil nitrogen concentrations (from nitrogen deposition and release
during mineralization), which precludes a rigorous evaluation of the model
responses to likely nitrogen perturbations. Overall, we demonstrate that
elucidating ecological mechanisms via meta-analysis can identify deficiencies
in ecosystem models and empirical experiments. |
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