Contribution to the phytoecological study of the biodiversity of the dune cord of El-Mesrane in the Wilaya (Province) of Djelfa in Algeria
The various dune fixation actions began in 1982 in the study area (El Mesrane –Djelfa) at the level of the dune ridge with very interesting results, on the one hand for the control of desertification through the creation of a microclimate that ensures the ecological sustainability of fragile ecosystems. This work was carried out in the two projects (1) and (2) in the study area. The objective of the study is summarized in the floristic and ecological char-acterization of the vegetation subject to fixation and other left without fixa-tion or natural regeneration. These dunes have a poorer floristic diversity than those fixed by Retama Retam webb and Tamarix gallica. A significant diversity of 26 species was encountered on dunes naturally fixed by vegeta-tion.The Shannon-Weiner diversity index for the vegetation of natural fixa-tion was found to be H’= 2.05; however, this index for dunes naturally fixed by Retama retam and Tamarix gallicawas 2,61 and 2,5, respectively. In gen-eral, dicotyledonous plant families such as the Asteraceae, Fabaceae and Poaceae were mostly encountered. Moreover, the distribution of biologic types is mainly characterized by the predominance of Chamephytes and The-rophytes. The degradation of the environment due to the anthropogenic pressure favors the high presence of Therophytes. These findings allowed deducing that the degradation of vegetation is mainly attributed to climatic conditions and overgrazing.