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| Titel |
Data-based modelling and environmental sensitivity of vegetation in China |
| VerfasserIn |
H. Wang, I. C. Prentice, J. Ni |
| 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 ; 10, no. 9 ; Nr. 10, no. 9 (2013-09-04), S.5817-5830 |
| Datensatznummer |
250085321
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| Publikation (Nr.) |
 copernicus.org/bg-10-5817-2013.pdf |
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| Zusammenfassung |
| A process-oriented niche specification (PONS) model was constructed to
quantify climatic controls on the distribution of ecosystems, based on the
vegetation map of China. PONS uses general hypotheses about bioclimatic
controls to provide a "bridge" between statistical niche models and more
complex process-based models. Canonical correspondence analysis provided an
overview of relationships between the abundances of 55 plant communities in
0.1° grid cells and associated mean values of 20 predictor variables.
Of these, GDD0 (accumulated degree days above 0 °C),
Cramer–Prentice α (an estimate of the ratio of actual to equilibrium
evapotranspiration) and mGDD5 (mean temperature during the period above
5 °C) showed the greatest predictive power. These three variables
were used to develop generalized linear models for the probability of
occurrence of 16 vegetation classes, aggregated from the original 55 types by
k-means clustering according to bioclimatic similarity. Each class was
hypothesized to possess a unimodal relationship to each bioclimate variable,
independently of the other variables. A simple calibration was used to
generate vegetation maps from the predicted probabilities of the classes.
Modelled and observed vegetation maps showed good to excellent agreement
(κ = 0.745). A sensitivity study examined modelled responses of
vegetation distribution to spatially uniform changes in temperature,
precipitation and [CO2], the latter included via an offset to α
(based on an independent, data-based light use efficiency model for forest
net primary production). Warming shifted the boundaries of most vegetation
classes northward and westward while temperate steppe and desert replaced
alpine tundra and steppe in the southeast of the Tibetan Plateau. Increased
precipitation expanded mesic vegetation at the expense of xeric vegetation.
The effect of [CO2] doubling was roughly equivalent to increasing
precipitation by ~ 30%, favouring woody vegetation types,
particularly in northern China. Agricultural zones in northern China
responded most strongly to warming, but also benefited from increases in
precipitation and [CO2]. These results broadly conform to previously
published findings made with the process-based model BIOME4, but they add
regional detail and realism and extend the earlier results to include
cropping systems. They provide a potential basis for a broad-scale assessment
of global change impacts on natural and managed ecosystems. |
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