The arid and semi-arid regions of the extreme west of Algeria represent in the current state, a transitional environment between the steppes and matorrals.The current vegetation cover, largely constituted by steppe species, allows us to understand what must have been the progressive evolution of plant structures and architectures; at least until the Trara; according to climatic modifications, then most often and in a regressive way; according to a human impact more and more present. This study on the dynamics is based on the phyto-ecological approach by comparison at the scale of the ecological station..The method of Transects is used to know the effect of the modifications of the environment (exposure, slope, ground...) on the distribution of the vegetation in other words to determine to understand the dynamics The results obtained are likely to provide us with valuable information as well on the evolution as on the situation of the degraded zones.Indeed, steppe and presteppe vegetation occupy important surfaces, but also in a more limited way almost everywhere in the region.The pre-steppe vegetation with xeric determinism has remained essentially confined to the altitudes, such as Pistacia, Pinus ,Olea etc., with an extremely low development and where the grassy and therophytic cover clearly dominates. Despite the intensity of anthropogenic degradation, the irreversibility stage is not yet achieved; since the advent of a rainy period leads to a more or less rapid recovery of the vegetation.

Dynamics, Phyto-ecology, Arid/semi-arid, Matorral, Presteppe formation, Therophytization, Maghnia. ( Oranie- Algeria).

environmental engineering

Presentation: poster