Floristic Composition and Soil Properties of Wadi Araba, a Typical Arid Ecosystem in the Northeastern Desert of Egypt

Wadi Araba, situated in the northern sector of Egypt's Eastern Desert, represents a typical hyper-arid wadi ecosystem where geomorphology, soil heterogeneity, and extreme climatic conditions all interact to shape vegetation structure. This study set out to: (1) document floristic composition and the life-form spectrum of the wadi; (2) characterize spatial variation in key soil properties; and (3) analyze soil–vegetation relationships with the goal of identifying the main edaphic controls influencing plant distribution. A total of 27 stands were surveyed and 96 wild plant species from 30 families were recorded. The flora is dominated by Saharo-Sindian elements (40.63%), followed by mixed Saharo-Sindian/Sudano-Zambezian and Irano-Turanian categories, in relation to the location of the wadi at the crossroads of major phytogeographic regions. Lifeform analysis indicates a predominance of therophytes (37.5%) and chamaephytes (32.3%), consistent with adaptations to unpredictable rainfall, high evapotranspiration, and prolonged drought typical in arid landscapes. Perennials make up 61.47% of the species while annuals make up 36.45% and biennials only 2.08%. The soil analysis showed a preponderance of sandy textures with a mean of 89.57%, low organic carbon, and slightly alkaline pH values ranging from 7.85 to 8.49. Electrical conductivity varied widely across the area, suggesting local salt accumulations, while soluble ions and SAR values indicated variable salinity and sodicity at different sites. Vegetation is strongly constrained by these edaphic gradients, with xerophytic and halophytic species favored in locally saline or poorly drained microhabitats and more diverse assemblages on coarse, better-drained terraces.