Vegetation dynamics under variable conditions in the famous sandy steppe of southern Tunisia
During last decades, the natural vegetation cover in southern Tunisia, mainly dominated by dwarf and sparse shrub, was continuously disturbed under various human activities especially on sandy soil (easily eroded). The ecological characteristics (soil structure and texture, vegetation, topography) of sandy steppes, with Rhanterium suaveolens Desf., enhanced their sharp decline. This study aims to investigate the vegetation status of two R. suaveolens steppes (R: protected; r: degraded) under different conditions in five sites belonging to southern Tunisia using the quadrat point method and some ecological indicators. Main results show that vegetation cover is related to climatic conditions. Plant density is mainly affected by rainfall and human activities. The annual and perennial density and cover are high during the rainy season (spring) compared with the dry one (fall). The degraded steppes (r) are mainly dominated by annual plants but the protected steppes (R) contain more perennials. This work can be very useful for the sustainable sandy steppes management under different stress and human disturbances in dry area. It presents a great national and international importance (economic, social, nature conservation) such as job creation and limiting rural exodus.