Defining units for savanna management in Sudano-sahelian areas

Management-oriented identification of vegetation types is needed in Mali for production savannas devoted to fuel-wood and charcoal production. This study seeks to determine which factor can be used to identify management units in relation to vegetation characteristics. Three production savannas, covering 1404 ha, were inventoried in the Zan Coulibaly district near Bamako. Structural variables on each inventoried plot, e.g. basal area or tree density, were measured to characterize the vegetation. Site variables such as soil depth and toposequence phase (plain, hillside or plateau) were determined to characterize the environment and anthropic pressure. Multivariate analyses were used to define vegetation units from structural variables, and to relate these to site variables. Five vegetation units were identified. A significant relationship was detected between these units and site variables. Significant differences were found in terms of structural variables between toposequence phases and between the three savannas. The results were consistent with a gradient from plain to plateau with decreasing logging intensity and decreasing soil depth. The vegetation in each toposequence phase was made up of a mosaic of vegetation units. In conclusion, toposequence phases can be used as the basis for stratifying production savannas in management units. (c) 2006 Elsevier B.V. All fights reserved.