Science et changements planétaires / Sécheresse


Phytogeography of the Zakouma National Park (South-Eastern Chad) Volume 20, issue 3, juillet-août-septembre 2009


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Cirad Département ES, UR AGIRs, TA C-22/E, Campus International de Baillarguet, 34398. Montpellier cedex 5, France, 10, Rue de Florette 30250 Villevieille France, Projet Curess BP 552, N’Djamena, Tchad

Several vegetation inventory campaigns were carried out between 2004 and 2006 in the woody communities of the Zakouma National Park in South-East Chad. The data obtained, coupled with SPOT 5 images and the pedological map of the park, made it possible to carry out the typology of this Sudano-Sahelian vegetation. Four vegetation types including 11 vegetation units were highlighted. They are Combretaceae savannas, with six well differentiated units, and Acacia seyal savannas with three units, which occupy respectively 67% and 26% of the surface of the park. A third formation is represented by grassy savannas which cover 7% of the protected area. The fourth formation corresponds to the Riverine forests. One of the characteristics of the Park of Zakouma is related to grassy savannas, marshy in the rainy season, which play a paramount role in the functioning of this ecosystem by ensuring the availability of water and the timelessness of the pastures for the fauna during the dry season. The main goal of this vegetation map lies in the comprehension of the states of succession of this vegetation under the combined effect of the browsing pressure of elephants, whose population is increasing regularly, and the recurring episodes of dryness.