Heterogeneite spatiale d'une foret tropicale humide de Sumatra: Effet de la topographie sur la structure floristique

Abstract

Tropical rain forests are characterized by a complex and spatially heterogeneous structure. It is essential to analyze the factors of this heterogeneity in order to set up sustainable management policies in these environments. We have studied the influence of topography on floristic structure, considering 3 ha of forest with contrasted relief. Correspondence analysis has shown that topography acts through drainage, leading to different specific compositions on ridge, slope and valley. It operates also in relation to forest dynamics, favoring pioneer species on steep slopes. In addition, this influence decreases as topographic heterogeneity is reduced: other factors related to forest internal characteristics then govern floristic structure. Moreover, this study brings new data concerning floristic composition and ecology of forests in this area, as well as topographical preferences of many species. Topography appears to be a key factor regarding the structure and the dynamics of tropical rain forests on contrasted relief, and should be considered in modeling.