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| Titel |
Drought impacts on vegetation in the pre- and post-fire events over Iberian Peninsula |
| VerfasserIn |
C. M. Gouveia, A. Bastos, R. M. Trigo, C. C. Dacamara |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 12, no. 10 ; Nr. 12, no. 10 (2012-10-19), S.3123-3137 |
| Datensatznummer |
250011147
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| Publikation (Nr.) |
 copernicus.org/nhess-12-3123-2012.pdf |
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| Zusammenfassung |
The present work aims to study the combined effect of drought and large
wildfires in the Iberian Peninsula relying on remotely sensed data of
vegetation dynamics and leaf moisture content, in particular monthly NDVI,
NDWI and NDDI time series from 1999–2009, derived from VEGETATION dataset.
The impact of the exceptional 2004/2005 drought on vegetation was assessed
for vegetation recovering from the extraordinary fire season of 2003 and on
the conditions that contributed to the onsetting of the fire season of 2005.
Drought severity was estimated by the cumulative negative effect on
photosynthetic activity (NDVI) and vegetation dryness (NDDI), with about
2/3 of Iberian Peninsula presenting vegetative stress and low water
availability conditions, in spring and early summer of 2005. Furthermore,
NDDI has shown to be very useful to assess drought, since it combines
information on vegetation and water conditions. Moreover, we show that
besides looking at the inter-annual variability of NDVI and NDDI, it is
useful to evaluate intra-annual changes (δNDVI and δNDDI), as
indicators of change in vegetation greenness, allowing a detailed picture of
the ability of the different land-cover types to resist to short-term dry
conditions.
In order to assess drought impact on post-fire regeneration, recovery times
were evaluated by a mono-parametric model based on NDVI data and values
corresponding to drought months were set to no value. Drought has shown to
delay recovery times for several months in all the selected scars from 2003.
The analysis of vegetation dynamics and fire selectivity in 2005 suggests
that fires tended to occur in pixels presenting lower vegetative and water
stress conditions during spring and early summer months. Additionally,
pre-fire vegetation dynamics, in particular vegetation density
and water availability during spring and early summer, has shown to influence
significantly the levels of fire damage. These results stress the role of
fuel availability in fire occurrence and impact on the Iberian Peninsula. |
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