Study of the degradation of steppic rangelands in béni mathar and maâtarka communes (northeastern of morocco) [Etude de la dégradation des pâturages steppiques dans les communes de Maâtarka et Béni Mathar (Maroc oriental)]

This study concerns the rangeland system of northeastern of morocco. it aims to identify the changes of pastoral resources through multitemporal analysis of vegetation maps in two contrasting rural communes: béni mathar in the north and maâtarka in the south. the dynamic,observed since the seventies,reflects a disappearance of rangeland sites in a good state. these sites are continually substituted by a cleared areas and others sites dominated by degradation indicator species indicating degradation. this dynamic is accompanied by a decrease in rangeland dry matter production; estimated annually to 2.8 kg per hectare. rainfall data of the study area show very large spatio-temporal variations. the cumulative deviations relative to the average rainfall (rainfall index) reflect a climate change during the seventies,materialized in recent decades by a drying trend from 36 to 39% in beni mathar and maâtarka respectively (almost one dry year in 3 successive years). the climate effect on vegetation dynamics is present in the study area. its intensity seems more amplified in the presence of the most pressing anthropozoïc factors on pastoral resources.