Plant communities in the Tamanrasset region, Ahaggar, Algeria

Several vegetation communities present in different wadi types are described from newly sampled regions in the Ahaggar region around Tamanrasset. The wadi types ranged from rocky substrates to more gravelly types through to deep sandy soils. An ordination applying correspondence analysis suggested altitude and soil substrate as the major ecological gradients at work. The results of this analysis enabled the identification of six associations. These are all described in detail focusing on the floristic list, their relation to the phytosociological framework proposed by Quézel (1965) and their ecological characteristics. Among the six associations, two are new : Rhus tripartita-Olea europaea subsp. laperrinei and Acacia raddiana-Salvadora persica communities. The former association is found in rocky wadis while the latter is typical of much larger wadi beds with a compact sandy ground. The four other associations were confirmed and described in regions not sampled before. These are Cassia aschrek-Panicum turgidum community – found generally on sandy-gravelly substrates, Leptadenia pyrotechnica-Chrozophora brocchiana community ranging from sandy-silty, sandy to sandy gravelly ground, the Tamarix aphylla-Farsetia ramosissima community found on wide sandy wadis and the Tamarix gallica-Desmostachya bipinnata typical of wadis where the water is close to the surface. The described plant communities are discussed in a wider geographical context.