Evaluation de la diversité floristique en palmeraies (Phoenix dactylifera) de la région d'Ouargla (Sahara septentrional algérien) suivant les différents niveaux d'entretien

Evaluation of Floristic Diversity in Palm Groves (Phoenix dactylifera) of Ouargla Region (Northern Algerian Sahara) According to Different Maintenance Levels. The floristic diversity of the ground vegetation of date palm groves of South East of Algeria (Ouargla, Northern Sahara) was evaluated in three palm groves with three maintenance levels: well maintained, moderately maintained and neglected palm groves. The results obtained from systematic sampling of ground vegetation revealed a floristic richness of 27 species belonging to 19 families. The most common species are Cynodon dactylon (32.9%), Phragmites communis (10.4%) and Juncus maritimus (7.7%). Specific richness indicates that the well maintained and moderately maintained palm groves are the richest in species. The Jaccard similarity index shows a great floristic difference between maintenance levels (6% -15%). The Simpson index indicates a very high diversity between maintenance levels (0.2-0.5). The most abundant biological types are thérophytes (41.7%) and hemi cryptophytes (20.1%). The variation of the species composition of the ground vegetation depends on the maintenance of the palm groves