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| Titel |
Impacts of climate change on water balance, vegetation productivity and soil erosion in southern Portugal |
| VerfasserIn |
João Pedro Nunes, Julia Seixas, Jan Jacob Keizer |
| 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 |
250058063
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| Zusammenfassung |
| The impacts of a warmer and drier climate on water balance, vegetation productivity and soil
erosion in southern Portugal, caused by global climate change, were evaluated using the
SWAT ecohydrological model and the MEFIDIS event-based erosion model. The
study focused on a humid region, occupied by vineyards, croplands and commercial
pine/eucalyptus forests; and a semi-arid region, occupied by croplands and cork oak stands.
SWAT was applied at the regional scale for several meso-scale watersheds, and MEFIDIS
was applied to one catchment in each region. The scenario (PROMES regional climate
model using the A2 CO2 emissions scenario) points to higher temperature, lower
rainfall (esp. in the dry season) and higher rainfall intensity during rain days; the
scenario was used to create synthetic storms based on present-day measured rainfall
events.
The results indicate that a decrease in rainfall would result mostly in a decrease in water
yield (surface and subsurface runoff) and groundwater recharge, leaving effective
evapotranspiration and wet season soil moisture close to present-day levels. The negative
impacts of climate change (especially the increased length and severity of the summer dry
season) could be counteracted by a shift in vegetation growth towards the wet season (thanks
to less cold-season temperature stress days), combined with the positive impact of higher
CO2 concentrations; this would result in modest productivity increases for most vegetation
types.
As for soil erosion, the simulation results indicate that the increase in vegetation cover is
sufficient, in many cases, to decrease or counterbalance the impacts of increased storm
intensity on soil erosion at all spatial scales, leading to lower erosion in the dry catchment and
a modest increase in the humid catchment. Catchment sediment yield is noticeably more
sensitive to the climate change scenarios than within-watershed soil erosion, mostly due
to the impacts of changes to connectivity; and, within the watershed, impacts on
soil erosion vary with landcover type, with croplands suffering the most negative
impacts. |
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