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Seasonal variations of the floristic characteristics and chemical composition of Saharan routes in Southern Algeria Volume 20, issue 4, octobre-novembre-décembre 2009

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Authors
Laboratoire Bioressources sahariennes, préservation et valorisation Faculté des sciences Université de Ouargla 30000 Ouargla Algérie, Laboratoire de Biogéochimie des milieux désertiques Faculté des sciences Université de Ouargla 30000 Ouargla Algérie

The Saharan climate is characterized by limited and irregular rainfall, high temperatures and intense brightness, and a high level of evaporation. The result of these extreme desert conditions is that the remaining meagre plant cover develops coping strategies enabling it to exploit to the maximum less favourable weather to proliferate. To better understand the effect of seasonal variations on the behaviour of Saharan floristic and nutritious vegetation we conducted a two-year temporal study of the different camel routes of the septentrional Algerian Sahara. The floristic study showed that ephemeral plants (achebs) appear after the rain and perform their full vegetative cycle before the soil is parched. They thus appear mostly in the spring (73%) and in winter (30%), and are lowest in autumn (12%) and summer (9%). For perennial plants, seasonal variations reflect on their production of biomass. For the chemical composition of species, we registered a net change for the content in MAT and tannins that are higher in the spring due to the effect of the increasing leaves/stem ratio. On the other hand, high temperatures and dry summers generate an increase of compounds and absence of cellulose which will reach their maximum in the following seasons.