Context: Riparian forests along watercourses of Burkina Faso are fragmented by anthropogenic pressure and
climate change. These riparian vegetations are composed by gallery forests, ripicole forests and ripicole cords. This study assessed effects of protection status (i.e. PA - protected area vs. communal area - CA) on vegetation composition and diversity of Mouhoun river in two contrasted climatic zones (Sudanian and Sahelo-Sudanian) in Burkina Faso.
Methods: Rectangular plots (500 m²) with varying width and length, and covering the whole riparian forests cross section were used following perpendicular transects across the riverbed. A total of 231 plots were inventoried. Alpha diversity indices (Shannon, Pielou and Simpson), beta diversity index (Sorensen) and fidelity index (Phi) were calculated and statistical analysis (non-parametric Kruskal-Wallis) were performed to better describe riparian vegetation in each site.
Results: A total of 265 plant species, including 177 ligneous and 88 herbaceous, were recorded in the Mouhoun River riparian forests along the two sites. These species are distributed among 125 genera and 59 families. Species richness only had distinctive variation between protected area (PA) and communal area (CA) in the two climatic zones. Alpha diversity indices were highest in the Sudanian zone. The beta diversity showed more dissimilarity between climatic zones than between protected and communal areas. Moreover, the Fidelity index showed great difference in species composition in the two climatic zones with highest diagnostic species in the Sudanian PA.
Conclusion and perspectives: This study highlighted the effectiveness of protection on riparian species richness by finding highest species richness in PA, and a distinctive variation on floristic composition in PA and CA of the two climatic zones. It also showed the great pressure on riparian ecosystems by the non-effect of protection on diversity indices. We need to monitor the effect of protection status on riparian forest plant communities in order to assess their evolution.

Riparian Forest, protected areas, climatic zone, diversity indices