The impact of elephant browsing on the vegetation in Waza National Park, Cameroon

Summary The Acacia seyal zone and the woodland zone of Waza National Park were sampled by means of line transects to assess damage to trees caused by elephants. In the Acacia seyal zone a total of 1503 trees was examined of which 65% were undamaged, 15% less than three-quarters browsed, and 20% were seriously damaged. Of all trees browsed and trees seriously damaged the majority (50% and 31%, respectively) came from the mature class. It is concluded that elephant damage to Acacia trees is not yet serious but if the trends continue (a doubling of the number of trees killed in 15 years), elephant might have considerable effects on Acacia dynamics and structure. In the woodland zone a total of 1431 trees was examined of which 55% were undamaged, 36% were less than three-quarters damaged and 9% were seriously damaged. Of all trees browsed and trees seriously damaged the majority (66% and 74%, respectively) came from the mature class. The woodland zone of Waza is under far less browsing pressure than that of Kalamaloue National Park, a dry season habitat for some of the Waza elephants. In both parks Acacia seyal, Piliostigma reticulatum, Combretum spp. and Balanites aegyptiaca were sought out as preferred foods. The study concludes with a recommendation for continued monitoring of the vegetation in Waza and Kalamaloue parks so that proper management can be taken to conserve it. It stresses the importance of the hydrological restoration of the Waza–Logone floodplain. Resume Les effets du broutage par les elephants dans la zone aAcacia seyal et la partie arbustive du Parc National de Waza ont eteevalues par echantillonnage sur des transects arm d'evaluer les degâts causes aux arbres. Dans la zone aAcacia seyal un total de 1503 arbres furent examines dont 65%etaient indemnes, 15% endommages a moins de trois-quarts et 20% serieusement endommages. Parmi les arbres broutes et les arbres serieusement endommages la majorite (50% et 31% respectivement) appartenait a la classe des adultes. Il est conclu que les degâts causes par les elephants ne sont pas encore graves mais que si la tendance se poursuit (doublement en 15 ans des arbre serieusement endommages), les elephants pourraient avoir des effets considerables sur la dynamique et la structure des Acacia. Dans la partie arbustive un total de 1431 arbres furent examines dont 55%etaient indemnes, 36% endommages a moins de trois-quarts et 9% serieusement endommages. Parmi les arbres broutes et les arbres serieusement endommages la majorite (66% et 74% respectivement) appartenait a la classe des adultes. La partie arbustive de Waza subit une pression bien moins importante que celle du Parc National de Kalamaloue, un habitat de saison seche pour les elephants de Waza. Dans les deux parcs, Acacia seyal, Piliostigma reticulatum, Combreturn spp., and Balanites aegyptiaca sont les nourritures preferees. Cette recherche se termine en recommendant de poursuivre les observations sur la vegetation des parcs de Waza et Kalamaloue de facon a entreprendre une gestion correcte pour la proteger. Elle insiste sur l'importance de la restauration du systeme hydrologique de la plaine d'inondation de Waza–Lagone.