Floristic composition of the mountainous massif of Tessala (Algerian west): Biodiversity and regressive dynamics of the forest ecosystem

The aim of the present work is to assess the state of the forest ecosystem of the tessala mountain (western algeria) by highlighting the ecological factors that control its dynamics. of the 10 stations sampled,132 species from 44 botanical families and 5 biological types were identified. the dominance of plant formations is based on xeric species: calycotome spinosa link.,chamaerops humilis l. and asparagus acutifolius l.,reflecting a banalization of the floristic communities. the analysis of edaphic and biological data by the afc revealed the main factors controlling the distribution of plant formations in the studied area and identified four clusters of stations according to the stage of degradation. group 1 corresponds to the least degraded stations correlated with phanerophytes and attached to the most advanced edaphic conditions. groups 2,3 and 4 are represented by highly degraded stations,correlated with therophytes and chamephytes. © 2017,university of mohammed premier oujda morocco.