1. Plant species composition and diversity are interactively driven by various environmental variables; including climate and land-use. 2. In the drylands of Ghana, the relative importance of these drivers for plant species composition and diversity are still poorly understood and this affects the identification and implementation of appropriate management strategies. 3. Using a combined gradient approach, the study sought to investigate the predictors of species richness and diversity of both the tree and the herbaceous layers in the drylands of Ghana. The study area comprises a steep climatic gradient from the forest-savanna transition to the sudan savanna of Ghana in combination with local gradients of land-use and soil conditions. 4. We used species richness and the Shannon-Wiener Index as response variables. Linear mixed-effect models and model selection were used to test the relationships between multiple environmental variables and the response variables. 5. We found clear differences in species composition between land-use types across the climatic gradient for both the tree and herbaceous layers. We also found differential responses of the herbaceous and tree layers to environmental drivers. Grazing pressure was the most important predictor of both response variables. Climatic aridity and fire were only directly important for herbaceous vegetation but not the tree layer although their indirect effects on the tree layer cannot be discounted. For soil properties, organic matter was important for both vegetation layers. Magnesium and base saturation were only important for the tree layer, while sodium, organic matter and pH were important for the herbaceous layer. 6. Synthesis: The marked differences in species composition for various land-uses along the climatic gradient imply that climate change will indeed affect vegetation. The observed importance of grazing for all response variables implies that land-use could override climate effects and that appropriate land management strategies could mitigate potential negative effects of climate change.