Climate variability over the past 12,500 years has shaped vegetation dynamics differently across West African savannas and forests

This study examines how climate variability from the Younger Dryas to the present shaped vegetation dynamics across West African savannas and forests using pollen-based compositional and functional analyses. Fossil pollen assemblages were grouped into ecological domains and harmonised with TRY trait records, retaining key traits including specific leaf area, leaf area, wood density and seed mass. Functional dispersion (FDis), squared chord distance (SCD), and principal coordinate analysis (PCoA) were used to assess regional and temporal patterns. Sahelian and Sudanian savannas were compositionally distinct but only weakly differentiated functionally, indicating broad overlap in occupied trait space. FDis increased significantly through time in the Sahel but showed no comparable trend in Sudan. Forest assemblages exhibited greater functional dispersion and compositional turnover than savannas. PCA, NMDS and PERMANOVA confirmed significant biome-scale compositional differentiation ( R ² = 0.1309, p = 0.001) and additional regional structuring. Trait patterns indicated more conservative ecological strategies in savannas, with higher wood density and lower specific leaf area, whereas forests were more functionally variable. Among environmental predictors, age, South Atlantic SST, δ ¹³ C and δ ¹⁸ O best explained variation in Sahelian FDis. Overall, Holocene vegetation change was biome-specific, regionally uneven, and marked by stronger compositional than functional differentiation within the savanna domain.