Dynamics of ecosystem services in the Oum Zes watershed

Located in the south-east of Tunisia (Governorate of Medenine), the Oum Zessar watershed, covering 350 km², is characterized by an arid Mediterranean climate and an average annual rainfall of 160 to 220 mm.With an agro-pastoral vocation, this site has benefited from major development programs. It is also found that its resources still suffer from the effect of anthropic pressure and climatic hazards.Thus, we proceeded to study the dynamics of ecosystem services according to three types of years: wet (1987 and 1999), normal (1984 and 2011) and dry (2001 and 2009) represented respectively by six maps of land use / land cover based on the processing and interpretation of Landsat TM and ETM + images.This work has allowed, among other things, to understand the total variation of ecosystem services before and after the implementation of the national strategy of Water and Soil Conservation (SWC), the first phase of which was carried out between 1990 and 2001 and the second phase between 2002 and 2011.