For the management and sustainable use of natural bio-resources it is necessary to quantify and valorize this heritage. In the case of the floristic diversity of Acacia tortilis, the only natural woody stand in Bechar-Algeria, scanty studies have been undertaken. Hence in this study, the general overview of the flora diversity state in the 58 plots of 9 stations was made by the analysis of various indexes: Shannon, Simpson, species evenness, floristic richness, disturbance index, biological and biogeographically spectra. We listed 103 species belonging to 37 families and 85 genus, the important plants belonged to the Asteraceae and Brassicaceae. The most important species are: Pulicaria crispa, Asteriscus graveolens, Launea arborescens, Matricaria pubescens, Moricandia arvensis, Farsetia aegyptiaca, Zilla macroptera. The biological spectrum indicated a dominance of the Chamaephytes and the predominance of the Therophytes; the phytogeographic spectrum showed an important endemism (44%) in which 36% species belong to the SaharoArabian element; The Shannon, Simpson, and Evenness diversity indices, were relatively high, thereby indicating a diversity variation between the stations, witch increased South towards North. It was prominent in Zouzfana, Taghit, and Abadla stations, and the higher values of disturbance Index reflected the greater level of anthropization in these courses. The future accumulation of this regression, many risk loss of the last naturally wall of desertification, biodiversity, national economy and sand advancement. Therefore, it is recommended to apply pastures protection, pastoral charge control, and elaborate an environmental value of this species.

The Argan is a multipurpose tree, endemic of South-west of Morocco and Algeria. It populates the Sahara and gives it a very particular physiognomy which is that of the sparse forest. The argan forest is a patchwork of species occupying distinct environmental niches across the Hamada of the South-west region of Algeria. It covers a region characterized by the aridity of the climate and extreme xericity with geological and pedological diversity that are the source of the broad range of magnificent landscapes (Hamada, wet-lands, escarpments, wadis, Regs, mountains). The association of plants with landscapes, reveals an environmental heterogeneity influencing the richness in species and allowing a dynamic and development of a diversified floristic cover mainly xerophilic and thermophilic. The originality of its flora is as-cribed to the presence of Saharo-sindian elements, Mediterranean and en-demic. This particular diversity is due to its biological characterization, sys-tematic and phytogeographic. Unfortunately, this ecosystem and its poten-tial for biological resources are today highly threatened and face degradation from disturbances and uncontrolled exploitation of the plant environment by anthropogenic activities, that requires the development of a preservation strategy. Our work emphasizes the importance of this genetic heritage and its original ecosystem, where the preservation must be secured through the establishment of a strict protection system of species throughout their natu-ral range.