Choice offixing speciesdunes andtheir effect onvegetation

Abstract

The experimental project of sand dune fixation was launched in 1982 by INRF in El-Mesrane, Djelfa. To fix the dunes and thus limit the advance of sand towards urban areas and agricultural lands and allow the natural vegetation and plantedto reclaim the lead and thus constitute a reserve of fodder for livestock. Several materials have been used for mechanical attachment that allows a temporary stabilization of sand input and departures, as some fixing species were tested for biological fixation with the success rate varies with soil and climatic factors.Our objectiveis to identifythespecies thatfixingsetand effectivelycolonizedthe dunepromotingbiological recovery.The overallpercentageof vegetationincreasesin line with thealtitudinalgradient, it occupies the lowesttopographiesof the dunewheresoil moistureis high andthe windis minimal; topographiesupwindare usually difficult tocolonize; they aredrier and moreexposed to thedominant(SW)wind,againstthetopographydownwindwho are inshelterare coolerand therefore easilycolonized. Eachspecies occupiesfixingthe dunedifferentlyas follows:RetamaretamWebb, grows throughoutthe dunedifferenttopographiesand exhibitions.Tamarix gallicaLcolonizesall topographiesof the dunepeaksexceptat high altitudeswindy. Tamarixaphylla(L.) Karst andEleagnusangustifoliaLcolonize thelower slopesand inter-dune areas.LyciumarabicumBoissrecordeda success rate ofless than 10%, mainly topographicpositionfacing the wind.