[en] Background
Though savannas dominate the terrestrial tropics, harvest a substantial species diversity and are considered as a major resource for developing countries, there is however little information available on their floristics and biogeography, specifically in Africa.
Aim
In this study we aimed to identify large-scale variation in woody species composition across tropical African savannas and dry forests, and determined the underlying environmental and historical factors.
Methods
We report multivariate analysis of more than 200 samples describing the woody species composition of savanna vegetation across Africa. The samples extend from 18° N to 26° S and from 17° W to 48° E including 30 countries. The data were collated from published books and papers, the authors’ personal data and a few websites.
Main results
Correspondence analysis showed a clear differentiation in woody species composition in the north and west (Sudanian Region) from those in the east and south (Zambezian Region). The floristic transition between the two groups was in north eastern Africa (Uganda, Kenya, Ethiopia and Somalia) where the barrier of the equatorial forest zone does not intervene. Within each group, there was a strong floristic gradient related to annual rainfall.
Conclusion
We examined the relationship between environment (climate, altitude, geology, soils) and the floristic groups to highlight possible determining influences. We propose a pan-African classification that might assist in the development of management and conservation policies.
