EFFECTS OF THE RELIEF ON THE REGENERATION OF WOODY SPECIES IN BENIN'S SUDANIAN ZONE

The regeneration of woody species is of major interest to ecologists in connection with ecosystem renewal. This study aimed (i) to analyse the regeneration potential of vegetation units in Benin's Sudanian zone, (ii) to document the variations in regeneration potential according to the relief. A total of 615 survey plots 25 m(2) in area were marked out in 13 vegetation units in the Pendjari Biosphere Reserve. An inventory of regeneration was made by counting the number of individuals per species in each plot. We used the log-linear model with a Poisson regression to model regeneration density and the number of regenerating species for four types of relief. The regeneration potential of vegetation units in the Pendjari Biosphere Reserve closely reflects the species composition of the plant cover. The Poisson regression shows that the relief has a significant effect on regeneration density and on the number of regenerating species. Regeneration potential in floodplains and along rivers is significantly lower than in hilly and plateau areas. Compared to plateau areas (index 1), the indices for observed regeneration density along rivers, in floodplains and in hilly areas are 1.01, 0.67 and 2.1 respectively. The number of regenerating species increases from plateau to hilly areas, but drops from plateau areas to flood plains and riversides. Topographic conditions thus influence the establishment of woody species in Sudanian zones.