Ecological Study of Two Grasses: Cenchrus ciliaris and Digitaria commutate Endangered Autochthonous of the Dry Zone of Tunisia

摘要

The Saharian ecosystems present an important intensity of rising sensitization to: Erosion, and desertification whose impacts are irreversible. On the one hand, the weakness of the yield and the poverty of soil lead to a limited biodiversity. In addition to these difficulties, hydra is the main cause of the rarification of certain pastoral species such as Cenchrus ciliaris and Digitaria commutata. The ecological study underlines a distribution of these species which are very dependent on water resources in the dry regions of Tunisia. The bioclimatic (temperature, pluviometry) variations lead to modifications to these species from one area to another which are translated through several parameters. Concerning the number of bundles, the difference is important. The national park of Bouhedma records the highest number, compared with Bni khdach, Jerba, Khanguit aicha and Matmata respectively. The variation inter-site of study also is considerable by the study of the morphological parameters (height, number and length of leaves by bundle, number of ear) whose bundles of the national park Bouhedma occupy the first class.