Diversity, stand structure and ecosystem services of Ouagadougou regional urban forest, Burkina Faso

Urban forests are key natural solutions for biodiversity conservation in West Africa. However, increasing urban population negatively affects the ecological and social attributes of urban forests. This study assessed the woody diversity, stand structure, ecosystem services, and management of the Ouagadougou Regional Urban Forest in Burkina Faso. Forest inventory data were collected in 40 plots of 1000 m2, following a stratified sampling design based on the three vegetation types in the forest. Ecosystem services and forest management were assessed through semi-structured interviews with 120 informants. Data were analyzed using diversity attributes, structural attributes and ethnobotanical indicators. The findings showed a γ-diversity of 55 woody species from 44 genera and 20 families, distributed in tree savannas, shrub savannas and shrub steppes. Diversity attributes such as species richness, Shannon’s index, Pielou’s index, Simpson’s index as well as structural attributes i.e. stem DBH, tree height, basal area, tree density indicated significant variations between the three vegetation types (p-value < 0.05). The distribution of diameter and height classes revealed unstable populations associated with poor regeneration potential and recruitment problems. Ecosystem services included provisioning (77.5%), regulating (29.17), cultural (21.67%), and supporting (7.27%) services. However, the surrounding populations recognized the severe degradation of the forest due to agriculture, wood cutting, waste depositing, and settlements installation. This study showed that the regional urban forest contributes to biodiversity conservation and livelihood supports, but undergoes degradation, resulting in declining population dynamics and poor regeneration potential. As a provider of many ecosystem services, the regional urban forest must benefit from more restrictive policies and legislation on the management of urban green spaces. These policies must be strengthened in order to reduce the effects of urbanization on the forest.