How do climate and land use affect structural attributes, diversity and carbon sequestration at both vegetation and species levels in West African savanna ecosystems?

Research on land use impacts on woody diversity and carbon stocks in West African savannas has primarily focused on the vegetation level. However, a combined analysis at both vegetation and species levels offers a more nuanced understanding of carbon loss patterns and provides stronger guidance for management and conservation of threatened species. This study evaluated the effect of climate and land use change on woody structure, diversity and carbon stocks in two climate zone (Sudanian and Sudano-Sahelian) and four land use types reflecting a land use conversion gradient. Aboveground carbon stocks were calculated from dendrometric data using a generalized pantropical allometric equation. Carbon dynamics were analyzed along the conversion gradient (near natural vegetation → recent cropland → cropland remaining cropland → fallow), with near natural vegetation as the baseline. Analysis of variance revealed significant effects of both climate and land use types on woody diversity and carbon stocks (P < 0.05), with interactive effects observed only for diversity. The highest aboveground carbon losses occurred during conversion from near natural vegetation to recent croplands in both the Sudano-Sahelian (reduced by 69.8%) and the Sudanian zones (reduced by 84%). Species level analyses further showed that carbon-rich species such as Anogeissus leiocarpa were largely removed during recent cropland establishment, while socio-economically important species such as Vitellaria paradoxa, Parkia biglobosa, Tamarindus indica, and Lannea macrocarpa were retained. To limit carbon losses, the integration of nitrogen-fixing tree species such as Faidherbia albida could simultaneously enhance agricultural productivity, reduce deforestation pressure, and strengthen carbon storage in savanna ecosystems, thereby contributing to conservation goals at the landscape level.