DELIMITATION DES PEUPLEMENTS DU PISTACHIER DE L’ATLAS (Pistacia atlantica Desf.) DANS LA REGION ORIENTALE DU MAROC PAR LE G.P.S. COMBINE AU S.I.G.

Abstract

The Atlas pistachio (Pistacia atlantica Desf.) is an important ecosystem both at the ecological, biogeographical and economic level. This tree is at the same time protective and productive. In fact, it has many medical, pharmaceutical and economic interests. However, this species continues to decline from year to year because of climatic but mainly anthropogenic actions. The present work is to delimit Atlas pistachio populations in the eastern region of Morocco by using GPS combined to GIS. Thus, four sites were determined and classified according to tree density, namely: Oujda-Taourirt corridor (site 1); Jerada region (site 2); Tafrata plain (site 3); and Ain Beni Mathar-Figuig corridor (site 4). Associated species to Atlas pistachio were also identified, of which Ziziphus lotus was the most abundant in the four sites. Our study shows that Atlas pistachio occupies large areas in the eastern region of Morocco, but in scattered and isolated situation. It was found also grouped in form of islands at marabout places or in protected areas. The Atlas pistachio in eastern Morocco is adapted to different bioclimates from semi-arid and arid to saharian and grows on various soil types. This species is threatened mainly by overgrazing, anthropic pressure as well as severe drought of the eastern region of Morocco.