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| Titel |
Sensitivity of the south-east African C3/C4 vegetation balance to climatic changes and atmospheric CO2 during last 37 000 years - combining results from model simulations and paleodata |
| VerfasserIn |
Vyacheslav Khon, Yiming Wang, Birgit Schneider, Ralph Schneider |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250082057
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| Zusammenfassung |
| Although both changes in climate (i.e. temperature, precipitation) and atmospheric CO2 are
important factors controlling the fraction of C4 vegetation, little is known for their relative
contribution in shaping the C3/C4 vegetation evolution in the past. A paleorecord based on
stable carbon isotopes (δ13C) of sedimentary leaf wax in the Zambezi catchment has
demonstrated a shift from a C4-dominated vegetation during the last glacial period to more
C3-dominated vegetation in the Holocene. At the large scale, such changes can be linked to
an increase in atmospheric CO2. However, the temporary decoupled evolution of atmospheric
CO2 and C3/C4 ratio, as seen in the paleorecord during the LGM and Heinrich 1
event, suggests that other factors such as precipitation and temperature may have
also played an important role. In the present study we use the BIOME4 vegetation
model to systematically estimate the sensitivity of the relative abundance of C4
vegetation to changes in temperature, precipitation and CO2. Our model results confirm
that atmospheric CO2 is the primary control on the C3/C4 vegetation evolution in
southern tropical Africa. We also find that the sensitivity of the C4 abundance to
precipitation (δC4/δP) increases with both lower CO2 and temperature. Furthermore, the
sensitivity of the C4 plant abundance to temperature (δC4/δT) increases with a
decrease in CO2. Consequently, the relative importance of climatic factors (such as
temperature and precipitation) in controlling C4 vegetation may vary under different
background CO2 concentrations. To better understand the individual factors shaping
the C3/C4 vegetation evolution from the Zambezi catchment area, climate model
simulations (Kiel Climate Model, PMIP models) are used to drive the BIOME4
model. |
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