Soil Characteristics and Vegetation Patterns in the Arid Steppe Rangeland in Southeast Algeria (Biskra)

Abstract

This study aims to characterize soil properties, climate change and to investigate how these parameters influence the distribution of vegetation in the arid rangeland of Biskra (Algeria). Soil samples were collected from three stations in El-Haouch city. Physicochemical soil parameters were analysed in each phytoecological group of rangeland type. Relationships between soil traits were tested to determine spatial variation and their effects on arid rangeland. Furthermore, the influence of pedological factors on the distribution and establishment of vegetation was examined using redundancy analysis (RDA).  The Mann-Kendall and Pettitt trend tests were used to analyse the climate data. The observed climate trends showing significant changes from 1987 to 2019 include a considerable decrease in annual rainfall and an increase in temperature.  RDA showed that soil parameters that best explained the vegetation distribution were EC, pH, organic matter (OM), CaCO3, and soil texture. Atriplex halimus and Suaeda vermiculata in Salty depressions grew under higher soil salinity (EC = 10.2 mS/cm) compared to Retama retam and Thymelaea microphylla, which tolerate moderate soil salinity with low organic matter. Atriplex halimus and Tamarix gallica in Wadi beds grew in soils characterized by high pH values but relatively low in OM. Additionally, low organic matter content, high salinization, and anthropogenic pressures, such as overgrazing and agricultural expansion, further increase the vulnerability of these arid steppe ecosystems to degradation. These findings highlight the need for sustainable land management strategies to mitigate environmental stress and preserve steppe biodiversity.