Environmental Changes on the Southern Sides of Lake Chad (1951-1987) The southern limit of the sahelo-saharian sector with the sahelo-sudanian sector is about 13°N in term of vegetation types, the limit marks the change from thorny scrub to a woody non-throny vegetation in which the Combretaceae are important element of flora. This band of country covering 250-300 km of latitude is commonly known as the Sahel. It is well-suited to livestock production as there is little competition from agriculture except on the southern sides of the Lake. In this space there is many concurrency between pastoral people, agricultural people and fishers. -The vegetation of the lake Chad shores : The sandy approaches have cyperaceae (Cyperus sp., Scirpus sp.) and grasses (Cynodon dactylon, Imperata cylindrica) which develop on the zone between high and low tide. On the banks there are « flooding borders » constitued with Vossia cuspidata, Ludwigia spp. and Cyperus papyrus. This last one can separate from the banks and make floating islands diverting with the winds or running waters. The sandy shallows have a vegetation with Phragmites australis, or by place Typha domingensis. A legume, Aeschynomene elaphroxylon (dessin n°1) is charasteristic of the Lake Chad where it is known as « Ambadj » , it’s very light wood is used as floats. In the low water period with is four meters high, it can make thickets.  dessin n°1 : Aeschynomene elaphroxylon (Guill. et Perr.), Taub. (Papilionaceae) A : branche fleurie, B : étendard, C : ailes, D : carène, E : gynécée, F : fruits, G : moëlle |