Flore et communautés végétales des inselbergs du Sud-Est du Togo

The study characterizes the phytoecologic units of granito-gneissic inselbergs in south-eastern Togo. The vegetation has been described by the stigmatiste phytosociological approach of BRAUN-BLANQUET. On each inselberg, floristic samples (plots of 100 to 500 m2) were carried out along a transect joigning the peneplain to the summit. Each sample plot is also characterized by ecological descriptors. The collected data were coded in several matrices, according to the formats of the softwares, for the statistical processing. The Detendred Correspondence Analysis (DCA), the ascending hierarchical clustering (Classification Ascendante Hiérarchique ‒ CAH) and the Twinspan were applied to the samples in order to identify the phytosociological units and their ecological characteristics. Floristic inventories have identified 291 species belonging to 223 genera and 79 families mostly represented by Fabaceae (38.0 %), Poaceae (30.4 %) and Rubiaceae (26.6 %). The phanerophytes and therophytes are the most abundant biological types. The Guineo-Congolese species (18.1 %) and the Sudano-Guinean species (18.1 %) are the dominant phytogeographical types. The species such as Afrotrilepis pilosa and Cyanotis lanata represent the endemic angiosperms; but the study also revealed the presence of an endemic gymnosperm (Encephalartos barteri). Six plants groupings having aspects of dry forest, savannas and lawns were identified. The distribution of the plants grouping depends on soil depth, in relation with the position on the inselbergs.