DYNAMIQUE SPATIO-TEMPORELLE DU COUVERT VÉGÉTAL EN ZONE SEMI-ARIDE

Abstract

The vegetation of Algeria, in particular of the semi-arid regions, has undergone profound modifications during its history. The Boutaleb forest massif, located in a semi-arid zone (province of Setif); presents an important floristic potential, which is threatened by the persistence of several factors of anthropic origin, causing a regression of the vegetation. This requires vegetation monitoring to support sustainable forest management of these environments, which is now possible thanks to satellite imagery. The objective of this article, is to study the spatio-temporal dynamics of the vegetation cover of the said forest, between 2010 and 2021; based on remote sensing and the GIS tool. The methodological approach of the work is based on the use of Landsat satellite image data of two types: TM and OLI for two dates 2010 and 2021 (period of 11 years), and the calculation of the NDVI vegetation index, to identify changes in vegetation cover between the two dates chosen. The processing of satellite images showed a very significant spatio-temporal variation in the vegetation cover, indeed the analysis of the vegetation index (NDVI) and the production of the vegetation change map showed a decline and a significant degradation of the vegetation cover of the study area, between 2010 and 2021, of more than 21%. This regressive dynamic of the plant cover is justified by the intervention of several factors due, mainly to anthropogenic action (fires, overgrazing, etc.). The use of spatial remote sensing, makes it possible to highlight the degradation of the plant cover, and therefore to analyze the risk factors (natural and/or anthropogenic), and the future scenarios for the degradation of this ecosystem