Aim of the study:
The north-east of Algeria, which comprises an arid Saharan region with a sparse plant ecosystem, was the subject of a phytoecological analysis aimed at inventorying its plant species as well as identifying the factors impacting this random floral succession.

Material and methods:
Four oasis sites in the southern region of El Oued were sampled. Species richness, life forms, chorology, plant cover rate, spatial distribution and similarity were analyzed. The disturbance index of the plant cover was calculated. An evaluation of the effect of soil salinity and pH on halophytic plants was conducted. This study, carried out from 2019 to 2023, involved 80 surveys, and the statistical analysis applied the Xlstat V16 tools.

Results and conclusions:
45 species were identified, divided into 37 genera and 19 families. Poaceae were the most widespread, followed by Asteraceae and Fabaceae. Among life forms, therophytes and chamephytes were dominant. Chorologically, Saharo-Sindian species were the most represented, followed by endemic southern Mediterranean and Saharan species. The disturbance index revealed significant degradation of herbaceous species, particularly those associated with the original flora. Numerical analysis, on the one hand, indicated the progressive loss of certain species, probably due to anthropogenic activities such as overgrazing by wandering camel herds, as well as to climate change, and on the other hand, it demonstrated the existence of distinct groups of plant samples, reflecting the impact of environmental factors, where species richness is influenced by signs of degradation due to human activities.