The current study presents a comprehensive 65-year diachronic analysis of the Atriplexmauritanica-Suaeda fruticosa subassociation in eastern Chott Chergui, Algeria. By resurveying historical plots from 1954 in 2019, the present study quantifies shifts in taxonomic composition, life-form spectra, biogeographic affinities, and diversity metrics (Shannon-Wiener index, Pielou's evenness, Margalef's richness, Jaccard similarity, Cohen's d). Species richness declined by 26.1 %, with therophytes decreasing from 68 % to 51 % and chamaephytes increasing from 19 % to 31 %. A significant decline in Shannon diversity (from 3.97 to 3.70, Welch's t = 3.12, p<0.001) and a Jaccard similarity of only 0.46 confirm substantial floristic turnover. Endemic taxa persisted (100 %), while mesic Mediterranean and pluri-regional elements contracted. The emergence of Saharo-Sahelian Atractylis serratuloides highlights ongoing xerophytization under accelerating aridification. Conservation of this fragile ecosystem demands a combination of livestock exclusion and soil restoration, along with continuous climate monitoring. These efforts should be underpinned by multivariate and trait-based analyses to pinpoint the drivers of change. Beyond documenting a hallmark of Mediterranean desertification, our study delivers a concise, transferable framework for long-term vegetation-change assessments in other climate-sensitive steppes.