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| Titel |
Impact of climate manipulation on carbon fluxes of a Mediterranean shrubland in Sardinia |
| VerfasserIn |
Gabriele Guidolotti, Dario Liberati, Giovambattista de Dato, Paolo De Angelis |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051443
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| Zusammenfassung |
| Arid and semiarid woody shrublands make up approximately 35% of the global
terrestrial surface area, 24% of the global organic carbon and 16% of the global
aboveground biomass. Despite their potential impact on the global carbon balance, these
ecosystems and their responses to climate change are still poorly studied. With
the aim of investigating the potential effect of global environmental changes on
ecosystem function, we manipulated the microclimate in a Mediterranean shrubland
in the Island of Sardinia in Italy to increase soil and air night-time temperatures
and to reduce water input from precipitation. Temperature and water are the main
drivers for many biological and chemical processes, and could strongly affect the
principal C fluxes such as NEE (Net Ecosystem Exchange), TER (Total Ecosystem
respiration) and SR (Soil CO2 efflux). The experimental site consists of nine plots
(about 25 m2) with an automatic roof that covers the vegetation during the night
(Warming treatment, 3 plots) or during rainfall events (Drought treatment, 3 plots),
the remaining 3 plots are used as control. A canopy-chamber was developed and
tested to measure NEE and TER in the three treatments. Soil CO2 efflux was also
measured in each of the 9 plots, using a commercial Li-Cor 8100 soil chamber. All
measurements were carried out during the year 2010, after nine years of manipulative
experiment.
All the C fluxes examined showed a strong seasonality, with the highest rates during the
spring, when the high soil water content and the mild temperatures supported both the
photosynthetic and respiratory activity, and the lowest rates during the hot dry non-vegetative
summer season. The warming and drought treatments did not affect significantly the C fluxes
at any sampling date. The variability between plots was also high, as a consequence of the
high heterogeneity in plant composition. In this Mediterranean shrubland, already adapted to
extremely high temperatures and prolonged drought conditions, the increase of temperature
and the reduced water availability will unlikely affect ecosystem C fluxes. In the long term,
changes in plant composition could play a major role to determine the responses
of this community to climate changes, and their role on the biosphere C-balance. |
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