Floristic and phytoecological diversity of Holm Oak Quercus ilex forests in the Belezma Massif Biosphere Reserve, North-East Algeria

The holm oak is a species that forms interesting stands in the Belezma National Park (PNB). Studying it has allowed us to understand it's ecological and phytoecological characteristics. Despite the importance of this species, individual trees remain exposed to multiple threats. Surveys were carried out at the level of the massifs of Kassrou and Om rkhaa which enabled us to carry out the floristic groups of the Holm oak. The study area is characterized by high floristic diversity, with 120 plant species belonging to 106 genera and 34 families, 46 of which are not included in the list of flora of the Belezma National Park. The most dominant families are Asteraceae (32 species; i.e., 27%) and Fabaceae (13 species; i.e., 11%), which are also families that are frequently found in Algeria, particularly in the Mediterranean region. The study of the phytogeographical spectrum shows that the field stations studied are dominated by the Mediterranean element (75%, 58%). Analysis of the biological types revealed the predominance of hemicryptophytes (30.33%). Therophytes were present with a high percentage at the two study sites (21%, 32%); the disturbance indices were respectively 46%, and 50%, showing high anthropogenic pressure. It is important to take the necessary measures for the preservation and conservation of this precious heritage.