Response of Stipa lagascae R. and Sch. to Protection under Arid Condition of Southern Tunisia

The study was carried out at two sites (Menzel Habib and national park of Sidi Toui) of southern Tunisia which provided an aridity gradient to evaluate the effect of long term protection on the regeneration of Stipa lagascae R. and Sch., a high range value bunchgrass. In both sites total plant cover as well as density of S. lagascae and Rhanterium suaveolens, the key species of the arid sandy steppe were determined inside and outside protected areas. Results showed considerable and positive effects of protection on the parameters scored. S. lagascae which was very rare in the freely grazed areas is more abundant in the protected areas than Rhanterium suaveolens, a chamephytic species. This is an indication that grasses such as Stipa are more competitive than chamaephytes for soil water and nutrients when not grazed. When degradation is still reversible, the application of restoration techniques may permit high regeneration of S. lagascae.