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Universidade de Lisboa (2011)

Vegetation recovery in Portugal following large wildfire episodes

Bastos, Ana Filipa Ferreira

Titre : Vegetation recovery in Portugal following large wildfire episodes

Auteur : Bastos, Ana Filipa Ferreira

Université de soutenance : Universidade de Lisboa

Grade : Mestrado integrado em Engenharia da Energia e do Ambiente 2011

Résumé
As in the Mediterranean ecosystems, fire regimes in Portugal, , have been changing due to land-use modifications and climatic warming. Fire has become an important ecosystems’ disturbance, leading to soil impoverishment and desertification. In the European Mediterranean context, Portugal has registered the highest number of fire occurrences since 1980 and the larger burnt area over the past decade. Thus, an exhaustive study of vegetation recovery after fire events becomes crucial in land management. Two outstanding fire seasons were recorded in Portugal in 2003 and 2005, which coincided with extreme climatic events, a strong heat wave in 2003 and, in 2004/2005, one of the most severe droughts since early 20th century. The aim of the present study is to i) discriminate large burnt scars in Portugal during the 2003, 2004 and 2005 fire seasons, ii) monitor vegetation behaviour throughout the pre and the post fire periods and iii) identify physical and environmental factors driving post-fire recovery. The study makes extensive use of the mono-parametric model developed by Gouveia et al. (2010), based on monthly values of NDVI from 1998 to 2009, at 1km×1km spatial scale, as obtained from the VEGETATION-SPOT5 instrument. The model was previously validated and some corrections introduced. The proposed procedure allows identifying burnt scars, estimating vegetation recovery times for each scar and assessing the influence of fire damage, pre-fire vegetation density, plant traits and terrain characteristics on post-fire vegetation recovery.

Mots clés : NDVI ; Recuperação da vegetação ; Fogo ; Mediterrâneo

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Page publiée le 23 octobre 2013, mise à jour le 22 août 2018